1,747

^[1]

1,537

^[2]

89

109

Accrued investment income

1,844

994

867

Premium Receivable, Allowance for Credit Loss

44

Insurance and reinsurance balances receivable, net of valuation allowance - $44 and $44

10,480

10,357

Reinsurance Recoverable, Allowance for Credit Loss

314

316

Reinsurance recoverable on losses and loss expenses, net of valuation allowance - $314 and $316

^[3]

15,592

15,181

Reinsurance recoverable on policy benefits

206

197

Deferred policy acquisition costs

5,402

5,242

263

306

Prepaid reinsurance premiums

15,400

15,296

Other intangible assets

5,811

6,063

2,769

2,647

Investments in partially-owned insurance companies

2,813

1,332

8,822

7,581

190,774

176,943

Liabilities

67,811

62,690

17,652

16,771

Insurance and reinsurance balances payable

5,713

5,373

6,708

6,184

Securities lending payable

1,844

994

Accounts payable, accrued expenses, and other liabilities

14,052

12,214

Deferred Income Tax Liabilities

892

804

1,405

1,416

0

1,299

14,948

13,559

308

Commitments and contingencies (refer to Note 10)

131,333

121,612

Shareholders' equity

Common Shares (CHF 24.15 par value; 477,605,264 and 479,783,864 shares issued; 450,732,625 and 451,971,567 shares outstanding)

11,064

11,121

Common Shares in treasury (26,872,639 and 27,812,297 shares)

(3,644)

(3,754)

Additional Paid in Capital

9,815

11,203

Retained earnings

39,337

36,142

Accumulated other comprehensive income (AOCI)

2,869

619

59,441

55,331

Debt Securities, Available-for-sale, Allowance for Credit Loss

190,774

176,943

20

0

Fixed maturities available for sale, at amortized cost

85,188

82,580

Debt Securities, Held-to-maturity, Allowance for Credit Loss

44

0

Debt Securities, Held-to-maturity, Fair Value

$ 12,510

$ 13,005

Common Shares, shares issued | shares

477,605,264

479,783,864

Common Shares, shares outstanding | shares

450,732,625

451,971,567

Treasury Stock, Shares | shares

26,872,639

27,812,297

[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.
[3]	Net of valuation allowance for uncollectible reinsurance.

Consolidated Statements Of Operations and Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues
Net premiums written	$ 33,820	$ 32,275	$ 30,579
Increase in unearned premiums	(703)	(985)	(515)
Net premiums earned	33,117	31,290	30,064
Net investment income	3,375	3,426	3,305
Realized Investment Gains (Losses)	(498)	(530)	(652)
Net realized gains (losses):
Other-than-temporary impairment (OTTI) losses gross		(90)	(52)
Portion of OTTI losses recognized in other comprehensive income (OCI)	0	32	3
Net OTTI losses recognized in income		(58)	(49)
Net realized, Gain (Loss), Excluding Other-than-temporary Impairment Loss	(498)	(472)	(603)
Total revenues	35,994	34,186	32,717
Expenses
Losses and loss expenses	21,710	18,730	18,067
Policy benefits	784	740	590
Policy Acquisition Costs	6,547	6,153	5,912
Administrative expenses	2,979	3,030	2,886
Interest expense	516	552	641
Other (income) expense	(994)	(596)	(434)
Amortization of Purchased Intangibles	290	305	339
Chubb integration expenses	0	23	59
Total expenses	31,832	28,937	28,060
Income before income tax	4,162	5,249	4,657
Income tax expense (includes benefit of $(36), nil, and $(41) on unrealized gains and losses reclassified from AOCI)	629	795	695
Net income	3,533	4,454	3,962
Other comprehensive income (loss)
Unrealized appreciation (depreciation)	2,311	3,704	(2,298)
Reclassification adjustment for net realized (gains) losses included in net income	281	31	302
Other comprehensive income (loss) after reclassification for net realized gains included in net income	2,592	3,735	(1,996)
Change in:
Cumulative foreign currency translation adjustment	306	13	(802)
Postretirement benefit liability adjustment	(232)	(76)	(321)
Other comprehensive income (loss), before income tax	2,666	3,672	(3,119)
Income tax (expense) benefit related to OCI items	(416)	(605)	399
Other comprehensive income (loss)	2,250	3,067	(2,720)
Comprehensive income	$ 5,783	$ 7,521	$ 1,242
Earnings per share
Basic earnings per share	$ 7.82	$ 9.77	$ 8.55
Diluted earnings per share	$ 7.79	$ 9.71	$ 8.49

Consolidated Statements of Operations and Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income tax expense (benefit)	$ 36	$ 0	$ 41
Reclassification out of Accumulated Other Comprehensive Income [Member] \| AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Net realized gains (losses)	(281)	(31)	(302)
Income tax expense (benefit)	$ (36)	$ 0	$ (41)

Consolidated Statements Of Shareholders' Equity - USD ($) $ in Millions	Total	Common Shares	Common Shares in Treasury	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment [Member]	Retained Earnings Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]	AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member] Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Cumulative Translation Adjustment	Cumulative Translation Adjustment Cumulative Effect, Period of Adoption, Adjustment [Member]	Cumulative Translation Adjustment Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Accumulated Defined Benefit Plans Adjustment [Member]	Accumulated Defined Benefit Plans Adjustment [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Defined Benefit Plans Adjustment [Member] Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Accumulated Other Comprehensive Income
Balance – beginning of year at Dec. 31, 2017		$ 11,121	$ (1,944)	$ 13,978	$ 27,474	$ 264	$ 27,738	$ 1,450	$ (296)	$ 1,154	$ (1,187)	$ (22)	$ (1,209)	$ 280	$ 47	$ 327
Treasury Stock, Retired, Cost Method, Amount		0	0		0
Common Shares repurchased	$ (1,021)		(1,021)
Net shares redeemed under employee share-based compensation plans			347	(313)
Stock Issued During Period, Value, Stock Options Exercised				(49)
Share-based compensation expense				285
FundingDividendsDeclaredToRetainedEarnings				(1,344)
Net income	3,962				3,962
Funding Dividends Declared From Additional Paid In Capital					1,344
Dividends declared on Common Shares					(1,344)
Change in year, before reclassification from AOCI, net of income tax (expense) benefit of $(426), $(647), and $338								(1,960)
Amounts reclassified from AOCI, net of income tax (expense) of $(36), nil, and $(41)								261
Change in year, net of income tax (expense) benefit of $(462), $(647), and $297								(1,699)
Change in year, net of income tax (expense) benefit of $(4), $24, and $35											(767)
Change in year, net of income tax benefit of $50, $18, and $67														(254)
Balance – Ending of year at Dec. 31, 2018	50,312	11,121	(2,618)	12,557	31,700	(12)	31,688	(545)	0	(545)	(1,976)		(1,976)	73	0	73	$ (2,448)
Treasury Stock, Retired, Cost Method, Amount		0	0		0
Common Shares repurchased	(1,531)		(1,531)
Net shares redeemed under employee share-based compensation plans			395	(178)
Stock Issued During Period, Value, Stock Options Exercised				(82)
Share-based compensation expense				266
FundingDividendsDeclaredToRetainedEarnings				(1,360)
Net income	4,454				4,454
Funding Dividends Declared From Additional Paid In Capital					1,360
Dividends declared on Common Shares					(1,360)
Change in year, before reclassification from AOCI, net of income tax (expense) benefit of $(426), $(647), and $338								3,057
Amounts reclassified from AOCI, net of income tax (expense) of $(36), nil, and $(41)								31
Change in year, net of income tax (expense) benefit of $(462), $(647), and $297								3,088
Change in year, net of income tax (expense) benefit of $(4), $24, and $35											37
Change in year, net of income tax benefit of $50, $18, and $67														(58)
Balance – Ending of year at Dec. 31, 2019	55,331	11,121	(3,754)	11,203	36,142	$ (72)	$ 36,070	2,543	$ 0	$ 2,543	(1,939)		$ (1,939)	15	$ 0	$ 15	619
Treasury Stock, Retired, Cost Method, Amount		(57)	323		(266)
Common Shares repurchased	(516)		(516)
Net shares redeemed under employee share-based compensation plans			303	(195)
Stock Issued During Period, Value, Stock Options Exercised				(50)
Share-based compensation expense				255
FundingDividendsDeclaredToRetainedEarnings				(1,398)
Net income	3,533				3,533
Funding Dividends Declared From Additional Paid In Capital					1,398
Dividends declared on Common Shares					(1,398)
Change in year, before reclassification from AOCI, net of income tax (expense) benefit of $(426), $(647), and $338								1,885
Amounts reclassified from AOCI, net of income tax (expense) of $(36), nil, and $(41)								245
Change in year, net of income tax (expense) benefit of $(462), $(647), and $297								2,130
Change in year, net of income tax (expense) benefit of $(4), $24, and $35											302
Change in year, net of income tax benefit of $50, $18, and $67														(182)
Balance – Ending of year at Dec. 31, 2020	$ 59,441	$ 11,064	$ (3,644)	$ 9,815	$ 39,337			$ 4,673			$ (1,637)			$ (167)			$ 2,869

Statement of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax	$ (426)	$ (647)	$ 338
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	(36)	0	(41)
Net unrealized appreciation on investments, Change in year, income tax (expense) benefit	(462)	(647)	297
Cumulative translation adjustment, Change in year, income tax(expense) benefit	(4)	24	35
Pension liability adjustment, Change in year, income tax (expense) benefit	$ 50	$ 18	$ 67

Consolidated Statements Of Cash Flows - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Cash flows from operating activities

Adjustments to reconcile net income to net cash flows from operating activities

$ 3,533

$ 4,454

$ 3,962

Net Realized Gains Losses

498

530

652

Amortization of premiums/discounts on fixed maturities

367

395

592

Amortization of purchased intangibles

290

305

339

Deferred income taxes

(333)

(97)

16

4,664

(257)

570

846

1,051

654

Insurance and reinsurance balances payable

236

215

235

535

(302)

722

Accounts payable, accrued expenses, and other liabilities

(98)

(207)

375

Income taxes payable

46

(7)

161

Insurance and reinsurance balances receivable

(114)

(270)

(981)

Reinsurance recoverable

(336)

838

(1,165)

Deferred policy acquisition costs

(89)

(344)

(301)

(260)

38

(351)

Cash flows from investing activities

9,785

6,342

5,480

Purchases of fixed maturities available for sale

(26,298)

(25,846)

(24,700)

Purchases of to be announced mortgage-backed securities

0

(35)

(202)

(229)

(456)

Sales of fixed maturities available for sale

(6,419)

(531)

(207)

11,377

13,110

14,001

Sales of to be announced mortgage-backed securities

0

6

29

Maturities and redemptions of fixed maturities available for sale

3,880

611

315

12,450

9,039

7,352

Maturities and redemptions of fixed maturities held to maturity

995

946

1,124

(81)

(1,117)

516

(113)

(703)

16

(1,924)

(1,315)

(1,337)

Acquisition of subsidiaries (net of cash acquired of nil, $45, and nil)

907

1,390

980

0

(29)

0

Payment, including deposit, for Huatai Group Interest

(1,623)

(580)

Net Cash Provided by (Used in) Investing Activities

(470)

(657)

(533)

(7,521)

(5,905)

(2,935)

Cash flows from financing activities

(1,388)

(1,354)

(1,337)

(523)

(1,530)

(1,044)

Proceeds from issuance of repurchase agreements

988

2,828

2,171

2,354

2,817

2,029

Repayment of repurchase agreements

(1,301)

(510)

(2,001)

(2,354)

(2,817)

(2,019)

145

204

115

470

514

453

(386)

(303)

(358)

Net cash flows (used for) from financing activities

(87)

0

(2,082)

(151)

(1,991)

Effect of foreign currency rate changes on cash and restricted cash

8

20

(65)

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect

190

306

489

1,646

^[1],[2]

1,340

^[2],[3]

851

^[3]

Cash Acquired from Acquisition

^[2]

1,836

1,646

^[1]

1,340

^[3]

Supplemental cash flow information

Taxes paid

902

912

503

Interest paid

524

512

621

0

45

0

CHINA | Huatai Group [Member]

Cash flows from investing activities

Payment, including deposit, for Huatai Group Interest

$ (1,623)

$ (580)

$ 0

[1]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[3]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018 and 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Summary of significant accounting policies

12 Months Ended

Dec. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Summary of significant accounting policies

a) Basis of presentation

Chubb Limited is a holding company incorporated in Zurich, Switzerland. Chubb Limited, through its subsidiaries, provides a broad range of insurance and reinsurance products to insureds worldwide. Our results are reported through the following business segments: North America Commercial P&C Insurance, North America Personal P&C Insurance, North America Agricultural Insurance, Overseas General Insurance, Global Reinsurance, and Life Insurance. Refer to Note 15 for additional information.

The accompanying Consolidated Financial Statements, which include the accounts of Chubb Limited and its subsidiaries (collectively, Chubb, we, us, or our), have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and, in the opinion of management, reflect all adjustments necessary for a fair statement of the results and financial position for such periods. All significant intercompany accounts and transactions, including internal reinsurance transactions, have been eliminated.

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Amounts included in the Consolidated Financial Statements reflect our best estimates and assumptions; actual amounts could differ materially from these estimates. Chubb's principal estimates include:

•unpaid loss and loss expense reserves, including long-tail asbestos and environmental (A&E) reserves and non-A&E casualty exposures;

•future policy benefits reserves;

•amortization of deferred policy acquisition costs and value of business acquired (VOBA);

•reinsurance recoverable, including a valuation allowance for uncollectible reinsurance;

•the assessment of risk transfer for certain structured insurance and reinsurance contracts;

•the valuation of the investment portfolio and assessment of valuation allowance for expected credit losses;

•the valuation of deferred income taxes;

•the valuation of derivative instruments related to guaranteed living benefits (GLB);

•the valuation and amortization of purchased intangibles; and

•the assessment of goodwill for impairment.

b) Premiums

Premiums are generally recorded as written upon inception of the policy. For multi-year policies for which premiums written are payable in annual installments, only the current annual premium is included as written at policy inception due to the ability of the insured/reinsured to commute or cancel coverage within the policy term. The remaining annual premiums are recorded as written at each successive anniversary date within the multi-year term.

For property and casualty (P&C) insurance and reinsurance products, premiums written are primarily earned on a pro-rata basis over the policy terms to which they relate. Unearned premiums represent the portion of premiums written applicable to the unexpired portion of the policies in force. For retrospectively-rated policies, written premiums are adjusted to reflect expected ultimate premiums consistent with changes to incurred losses, or other measures of exposure as stated in the policy, and earned over the policy coverage period.

Mandatory reinstatement premiums assessed on reinsurance policies are earned in the period of the loss event that gave rise to the reinstatement premiums. All remaining unearned premiums are recognized over the remaining coverage period.

Premiums from long-duration contracts such as certain traditional term life, whole life, endowment, and long-duration personal accident and health (A&H) policies are generally recognized as revenue when due from policyholders. Traditional life policies

include those contracts with fixed and guaranteed premiums and benefits. Benefits and expenses are matched with income to result in the recognition of profit over the life of the contracts.

Retroactive loss portfolio transfer (LPT) contracts in which the insured loss events occurred prior to contract inception are evaluated to determine whether they meet criteria for reinsurance accounting. If reinsurance accounting is appropriate, written premiums are fully earned and corresponding losses and loss expenses recognized at contract inception. These contracts can cause significant variances in gross premiums written, net premiums written, net premiums earned, and net incurred losses in the years in which they are written. Reinsurance contracts sold not meeting the criteria for reinsurance accounting are recorded using the deposit method as described below in Note 1 k).

Reinsurance premiums assumed are based on information provided by ceding companies supplemented by our own estimates of premium when we have not received ceding company reports. Estimates are reviewed and adjustments are recorded in the period in which they are determined. Premiums are earned over the coverage terms of the related reinsurance contracts and range from one to three years.

c) Deferred policy acquisition costs and value of business acquired

Policy acquisition costs consist of commissions (direct and ceded), premium taxes, and certain underwriting costs related directly to the successful acquisition of new or renewal insurance contracts. A VOBA intangible asset is established upon the acquisition of blocks of long-duration contracts in a business combination and represents the present value of estimated net cash flows for the contracts in force at the acquisition date. Acquisition costs and VOBA, collectively policy acquisition costs, are deferred and amortized. Amortization is recorded in Policy acquisition costs in the Consolidated statements of operations. Policy acquisition costs on P&C contracts are generally amortized ratably over the period in which premiums are earned. Policy acquisition costs on traditional long-duration contracts are amortized over the estimated life of the contracts, generally in proportion to premium revenue recognized based upon the same assumptions used in estimating the liability for future policy benefits. For non-traditional long-duration contracts, we amortize policy acquisition costs over the expected life of the contracts in proportion to expected gross profits. The effect of changes in estimates of expected gross profits is reflected in the period the estimates are revised. Policy acquisition costs are reviewed to determine if they are recoverable from future income, including investment income. Unrecoverable policy acquisition costs are expensed in the period identified.

Advertising costs are expensed as incurred except for direct-response campaigns that qualify for cost deferral, principally related to long-duration A&H business produced by the Overseas General Insurance segment, which are deferred and recognized as a component of Policy acquisition costs. For individual direct-response marketing campaigns that we can demonstrate have specifically resulted in incremental sales to customers and such sales have probable future economic benefits, incremental costs directly related to the marketing campaigns are capitalized as Deferred policy acquisition costs. Deferred policy acquisition costs, including deferred marketing costs, are reviewed regularly for recoverability from future income, including investment income, and amortized in proportion to premium revenue recognized, primarily over a ten-year period, the expected economic future benefit period based upon the same assumptions used in estimating the liability for future policy benefits. The expected future benefit period is evaluated periodically based on historical results and adjusted prospectively. The amount of deferred marketing costs reported in Deferred policy acquisition costs in the Consolidated balance sheets was $226 million and $246 million at December 31, 2020 and 2019, respectively. Amortization expense for deferred marketing costs was $99 million, $109 million, and $114 million for the years ended December 31, 2020, 2019, and 2018, respectively.

d) Reinsurance

Chubb assumes and cedes reinsurance with other insurance companies to provide greater diversification of business and minimize the net loss potential arising from large risks. Ceded reinsurance contracts do not relieve Chubb of its primary obligation to policyholders.

For both ceded and assumed reinsurance, risk transfer requirements must be met in order to account for a contract as reinsurance, principally resulting in the recognition of cash flows under the contract as premiums and losses. To meet risk transfer requirements, a reinsurance contract must include insurance risk, consisting of both underwriting and timing risk, and a reasonable possibility of a significant loss for the assuming entity. To assess risk transfer for certain contracts, Chubb generally develops expected discounted cash flow analyses at contract inception. Deposit accounting is used for contracts that do not meet risk transfer requirements. Deposit accounting requires that consideration received or paid be recorded in the balance sheet as opposed to recording premiums written or losses incurred in the statement of operations. Non-refundable fees on deposit contracts are earned based on the terms of the contract described below in Note 1 k).

Reinsurance recoverable includes balances due from reinsurance companies for paid and unpaid losses and loss expenses and future policy benefits that will be recovered from reinsurers, based on contracts in force. The method for determining the reinsurance recoverable on unpaid losses and loss expenses incurred but not reported (IBNR) involves actuarial estimates consistent with those used to establish the associated liability for unpaid losses and loss expenses as well as a determination of Chubb's ability to cede unpaid losses and loss expenses under the terms of the reinsurance agreement.

Reinsurance recoverable is presented net of a valuation allowance for uncollectible reinsurance determined based upon a review of the financial condition of reinsurers and other factors. The valuation allowance for uncollectible reinsurance is based on an estimate of the reinsurance recoverable balance that will ultimately be unrecoverable due to reinsurer insolvency, a contractual dispute, or any other reason. The valuation of this allowance includes several judgments including certain aspects of the allocation of reinsurance recoverable on IBNR claims by reinsurer and a default analysis to estimate uncollectible reinsurance. The primary components of the default analysis are reinsurance recoverable balances by reinsurer, net of collateral, and default factors used to determine the portion of a reinsurer's balance deemed uncollectible. The definition of collateral for this purpose requires some judgment and is generally limited to assets held in a Chubb-only beneficiary trust, letters of credit, and liabilities held with the same legal entity for which Chubb believes there is a contractual right of offset. The determination of the default factor is principally based on the financial strength rating of the reinsurer. Default factors require considerable judgment and are determined using the current financial strength rating, or rating equivalent, of each reinsurer as well as other key considerations and assumptions. Changes in the valuation allowance for uncollectible reinsurance recoverables are recorded in Losses and loss expenses in the Consolidated statements of operations. Our methodology to calculate the valuation allowance was consistent with the new expected credit loss guidance adopted on January 1, 2020. Therefore, there was no change to the valuation allowance upon adoption. The more significant considerations include, but are not necessarily limited to, the following:

•For reinsurers that maintain a financial strength rating from a major rating agency, and for which recoverable balances are considered representative of the larger population (i.e., default probabilities are consistent with similarly rated reinsurers and payment durations conform to averages), the financial rating is based on a published source and the default factor is based on published default statistics of a major rating agency applicable to the reinsurer's particular rating class. When a recoverable is expected to be paid in a brief period of time by a highly rated reinsurer, such as certain property catastrophe claims, a default factor may not be applied;

•For balances recoverable from reinsurers that are both unrated by a major rating agency and for which management is unable to determine a credible rating equivalent based on a parent, affiliate, or peer company, we determine a rating equivalent based on an analysis of the reinsurer that considers an assessment of the creditworthiness of the particular entity, industry benchmarks, or other factors as considered appropriate. We then apply the applicable default factor for that rating class. For balances recoverable from unrated reinsurers for which the ceded reserve is below a certain threshold, we generally apply a default factor of 34 percent, consistent with published statistics of a major rating agency;

•For balances recoverable from reinsurers that are either insolvent or under regulatory supervision, we establish a default factor and resulting valuation allowance for uncollectible reinsurance based on reinsurer-specific facts and circumstances. Upon initial notification of an insolvency, we generally recognize an expense for a substantial portion of all balances outstanding, net of collateral, through a combination of write-offs of recoverable balances and increases to the valuation allowance for uncollectible reinsurance. When regulatory action is taken on a reinsurer, we generally recognize a default factor by estimating an expected recovery on all balances outstanding, net of collateral. When sufficient credible information becomes available, we adjust the valuation allowance for uncollectible reinsurance by establishing a default factor pursuant to information received; and

•For other recoverables, management determines the valuation allowance for uncollectible reinsurance based on the specific facts and circumstances.

The methods used to determine the reinsurance recoverable balance and related valuation allowance for uncollectible reinsurance are regularly reviewed and updated, and any resulting adjustments are reflected in earnings in the period identified.

The methods used to determine the valuation allowance for uncollectible high deductible recoverable amounts and valuation allowance for insurance and reinsurance balances receivable are similar to the processes used to determine the valuation allowance for uncollectible reinsurance recoverable. For information on high deductible policies, refer to section h) Unpaid losses and loss expenses, below.

Prepaid reinsurance premiums represent the portion of premiums ceded to reinsurers applicable to the unexpired coverage terms of the reinsurance contracts in-force.

The value of reinsurance business assumed is the deferred gain or loss related to loss portfolio transfers assumed and is calculated as the difference between the estimated ultimate value of the liabilities assumed under retroactive reinsurance contracts over consideration received. The gain or loss is amortized and recorded to Losses and loss expenses based on the payment pattern of the losses assumed. The unamortized value is reviewed regularly to determine if it is recoverable based upon the terms of the contract, estimated losses and loss expenses, and anticipated investment income. Unrecoverable amounts are expensed in the period identified. The value of reinsurance business assumed at December 31, 2020 and 2019 were immaterial.

e) Investments

Fixed maturities, equity securities, and short-term investments

Fixed maturities are classified as either available for sale or held to maturity.

•Available for sale (AFS) portfolio is reported at fair value, net of a valuation allowance for credit losses, with changes in fair value recorded as a separate component of AOCI in Shareholders' equity.

•Held to maturity (HTM) portfolio includes securities for which we have the ability and intent to hold to maturity or redemption and is reported at amortized cost, net of a valuation allowance for credit losses.

Equity securities are reported at fair value with changes in fair value recorded in net realized gains (losses) on the Consolidated statement of operations.

Short-term investments comprise securities due to mature within one year of the date of purchase and are recorded at fair value which typically approximates cost.

Interest, dividend income, and amortization of fixed maturity market premiums and discounts, related to these securities are recorded in Net investment income, net of investment management and custody fees, in the Consolidated statement of operations.

In addition, net investment income includes the amortization of the fair value adjustment related to the acquired invested assets of The Chubb Corporation (Chubb Corp). An adjustment of $1,652 million related to the fair value of Chubb Corp’s fixed maturities securities was recorded (fair value adjustment) at the date of acquisition. At December 31, 2020, the remaining balance of this fair value adjustment was $213 million which is expected to amortize over the next two years; however, the estimate could vary materially based on current market conditions, bond calls, and the duration of the acquired investment portfolio. In addition, sales of these acquired fixed maturities would also reduce the fair value adjustment balance. For mortgage-backed securities and any other holdings for which there is a prepayment risk, prepayment assumptions are evaluated and revised as necessary. Any adjustments required due to the resultant change in effective yields and maturities are recognized prospectively. Prepayment fees or call premiums that are only payable when a security is called prior to its maturity are earned when received and reflected in Net investment income.

Valuation allowance for fixed income securities

Management evaluates current expected credit losses (CECL) for all HTM securities each quarter. U.S. treasury and agency securities and U.S. government agency mortgage-backed securities are assumed to have no risk of non-payment and therefore are excluded from the CECL evaluation. The remaining HTM securities are evaluated for potential credit loss on a collective pool basis. We elected to pool HTM securities by 1) external credit rating and 2) time to maturity (duration). These characteristics are the most representative of similar risk characteristics within our portfolio. Chubb pools HTM securities and calculates an expected credit loss for each pool using Moody’s corporate bond default average, corporate bond recovery rate, and an economic cycle multiplier. The multiplier is based on the leading economic index and will adjust the average default frequency for a forward-looking economic outlook. Management monitors the credit quality of HTM securities through the review of external credit ratings on a quarterly basis.

Management evaluates expected credit losses (ECL) for AFS securities when fair value is below amortized cost. AFS securities are evaluated for potential credit loss on an individual security level but the evaluation may use assumptions consistent with expectations of credit losses for a group of similar securities. If management has the intent to sell or will be required to sell the security before recovery, the entire impairment loss will be recorded through income to net realized gains and losses. If management does not have the intent to sell or will not be required to sell the security before recovery, an allowance for credit losses is established and is recorded through income to net realized gains and losses, and the non-credit loss portion is recorded through other comprehensive income.

Examples of criteria that are collectively evaluated to determine if a credit loss has occurred include the following:

•The extent to which the fair value is less than amortized cost;

•Adverse conditions related to the security, industry, or geographic area;

•Downgrades in the security's credit rating by a rating agency; and

•Failure of the issuer to make scheduled principal or interest payments

AFS securities that meet any one of the criteria included above will be subject to a discounted cash flow analysis by comparing the present value of expected future cash flows with the amortized cost basis. Projected cash flows are driven primarily by assumptions regarding probability of default and the timing and amount of recoveries associated with defaults. Chubb developed the projected cash flows using market data, issuer-specific information, and credit ratings. In combination with contractual cash flows and the use of historical default and recovery data by Moody's Investors Service (Moody's) rating category we generate expected cash flows using the average cumulative issuer-weighted global default rates by letter rating.

If the present value of expected future cash flows is less than the amortized cost, a credit loss exists and an allowance for credit losses will be recognized. If the present value of expected future cash flows is equal to or greater than the amortized cost basis, management will conclude an expected credit loss does not exist.

Management reviews credit losses and the valuation allowance for expected credit losses each quarter. When all or a portion of a fixed maturity security is identified to be uncollectible and written off, the valuation allowance for expected credit losses is reduced by the same amount. In general, a security is considered uncollectible no later than when all efforts to collect contractual cash flows have been exhausted. Below are considerations for when a security may be deemed uncollectible:

•We have sufficient information to determine that the issuer of the security is insolvent;

•We receive notice that the issuer of the security has filed for bankruptcy, and the collectability is expected to be adversely impacted by the bankruptcy;

•The issuer of a security has violated multiple debt covenants;

•Amounts have been past due for a specified period of time with no response from the issuer;

•A significant deterioration in the value of the collateral has occurred;

•We have received correspondence from the issuer of the security indicating that it doesn’t intend to pay the contractual principal and interest.

We elected to not measure an allowance for accrued investment income as uncollectible balances are written off in a timely manner, typically 30 to 45 days after uncollected balances are due.

Prior to January 1, 2020, fixed income securities were evaluated individually for other-than-temporary impairment (OTTI) and a realized loss was recognized once certain criteria were met.

Other investments

Other investments principally comprise investment funds, limited partnerships, partially-owned investment companies, life insurance policies, policy loans, and non-qualified separate account assets.

Investment funds and limited partnerships

Investment funds, limited partnerships, and all other investments over which Chubb cannot exercise significant influence are accounted for as follows. Generally, we own less than three percent of the investee’s shares.

•Income and expenses from these funds are reported within Net investment income.

•These funds are carried at net asset value, which approximates fair value with changes in fair value recorded in net realized gains (losses) on the Consolidated statement of operations. Refer to Note 4 for a further discussion on net asset value.

•As a result of the timing of the receipt of valuation data from the investment managers, these investments are generally reported on a three-month lag.

•Sales of these investments are reported within Net realized gains (losses).

Partially-owned investment companies

Partially-owned investment companies where our ownership interest is in excess of three percent are accounted for under the equity method because Chubb exerts significant influence. These investments apply investment company accounting to determine operating results, and Chubb retains the investment company accounting in applying the equity method.

•This means that investment income, realized gains or losses, and unrealized gains or losses are included in the portion of equity earnings reflected in Other (income) expense.

•As a result of the timing of the receipt of valuation data from the investment managers, these investments are generally reported on a three-month lag.

Other

•Policy loans are carried at outstanding balance and interest income is reflected in Net investment income.

•Life insurance policies are carried at policy cash surrender value and income is reflected in Other (income) expense.

•Non-qualified separate account assets are supported by assets that do not qualify for separate accounting reporting under GAAP. The underlying securities are recorded on a trade date basis and carried at fair value. Unrealized gains and losses on non-qualified separate account assets are reflected in Other (income) expense.

Investments in partially-owned insurance companies

Investments in partially-owned insurance companies primarily represent direct investments in which Chubb has significant influence and as such, meet the requirements for equity accounting. Generally, we own twenty percent or more of the investee’s shares. We report our share of the net income or loss of the partially-owned insurance companies in Other (income) expense.

Derivative instruments

Chubb recognizes all derivatives at fair value in the Consolidated balance sheets in either Accounts payable, accrued expenses, and other liabilities or Other assets. Changes in fair value are included in Net realized gains (losses) in the Consolidated statements of operations. We did not designate any derivatives as accounting hedges. We participate in derivative instruments in two principal ways:

(i) To sell protection to customers as an insurance or reinsurance contract that meets the definition of a derivative for accounting purposes. This category principally comprised our GLB contracts; and

(ii) To mitigate financial risks and manage certain investment portfolio risks and exposures, including assets and liabilities held in foreign currencies. We use derivative instruments including futures, options, swaps, and foreign currency forward contracts. Refer to Note 10 for additional information.

Securities lending program

Chubb participates in a securities lending program operated by a third-party banking institution whereby certain assets are loaned to qualified borrowers and from which we earn an incremental return which is recorded within Net investment income in the Consolidated statement of operations.

Borrowers provide collateral, in the form of either cash or approved securities, at a minimum of 102 percent of the fair value of the loaned securities. Each security loan is deemed to be an overnight transaction. Cash collateral is invested in a collateral pool which is managed by the banking institution. The collateral pool is subject to written investment guidelines with key objectives which include the safeguard of principal and adequate liquidity to meet anticipated redemptions. The fair value of the loaned securities is monitored on a daily basis, with additional collateral obtained or refunded as the fair value of the loaned securities changes. The collateral is held by the third-party banking institution, and the collateral can only be accessed in the event that the institution borrowing the securities is in default under the lending agreement. As a result of these restrictions, we consider our securities lending activities to be non-cash investing and financing activities. An indemnification agreement with the lending agent protects us in the event a borrower becomes insolvent or fails to return any of the securities on loan.

The fair value of the securities on loan is included in fixed maturities and equity securities in the Consolidated balance sheets. The securities lending collateral is reported as a separate line in the Consolidated balance sheets with a related liability reflecting our obligation to return the collateral plus interest.

Repurchase agreements

Similar to securities lending arrangements, securities sold under repurchase agreements, whereby Chubb sells securities and repurchases them at a future date for a predetermined price, are accounted for as collateralized investments and borrowings and are recorded at the contractual repurchase amounts plus accrued interest. Assets to be repurchased are the same or substantially the same as the assets transferred, and the transferor, through right of substitution, maintains the right and ability to redeem the collateral on short notice. The fair value of the underlying securities is included in fixed maturities and equity securities. In contrast to securities lending programs, the use of cash received is not restricted. We report the obligation to return the cash as Repurchase agreements in the Consolidated balance sheets and record the fees under these repurchase agreements within Interest expense on the Consolidated statement of operations.

Refer to Note 4 for a discussion on the determination of fair value for Chubb's various investment securities.

f) Cash

We have agreements with a third-party bank provider which implemented two international multi-currency notional cash pooling programs. In each program, participating Chubb entities establish deposit accounts in different currencies with the bank provider and each day the credit or debit balances in every account are notionally translated into a single currency (U.S. dollars) and then notionally pooled. The bank extends overdraft credit to any participating Chubb entity as needed, provided that the overall notionally-pooled balance of all accounts in each pool at the end of each day is at least zero. Actual cash balances are not physically converted and are not commingled between legal entities. Any overdraft balances incurred under this program by a Chubb entity would be guaranteed by Chubb Limited (up to $300 million in the aggregate). Our syndicated letter of credit facility allows for same day drawings to fund a net pool overdraft should participating Chubb entities overdraw contributed funds from the pool.

Restricted cash

Restricted cash in the Consolidated balance sheets represents amounts held for the benefit of third parties and is legally or contractually restricted as to withdrawal or usage. Amounts include deposits with U.S. and non-U.S. regulatory authorities, trust funds set up for the benefit of ceding companies, and amounts pledged as collateral to meet financing arrangements.

The following table provides a reconciliation of cash and restricted cash reported within the Consolidated balance sheets that total to the amounts shown in the Consolidated statements of cash flows:


	December 31
(in millions of U.S. dollars)	2020		2019		2018
Cash	$	1,747	$	1,537	$	1,247
Restricted cash	89		109		93
Total cash and restricted cash shown in the Consolidated statements of cash flows	$	1,836	$	1,646	$	1,340

g) Goodwill and Other intangible assets

Goodwill represents the excess of the cost of acquisitions over the fair value of net assets acquired and is not amortized. Goodwill is assigned at acquisition to the applicable reporting unit of the acquired entities giving rise to the goodwill. Goodwill impairment tests are performed annually or more frequently if circumstances indicate a possible impairment. For goodwill impairment testing, we use a qualitative assessment to determine whether it is more likely than not (i.e., more than a 50 percent probability) that the fair value of a reporting unit is greater than its carrying amount. If our assessment indicates less than a 50 percent probability that fair value exceeds carrying value, we quantitatively estimate a reporting unit's fair value. Goodwill recorded in connection with investments in partially-owned insurance companies is recorded in Investments in partially-owned insurance companies and is also measured for impairment annually.

Indefinite lived intangible assets are not subject to amortization. Finite lived intangible assets are amortized over their useful lives, generally with an average original useful life of 25 years. Intangible assets are regularly reviewed for indicators of impairment. Impairment is recognized if the carrying amount is not recoverable from its undiscounted cash flows and is measured as the difference between the carrying amount and fair value.

h) Unpaid losses and loss expenses

A liability is established for the estimated unpaid losses and loss expenses under the terms of, and with respect to, Chubb's policies and agreements. Similar to premiums that are recognized as revenues over the coverage period of the policy, a liability for unpaid losses and loss expenses is recognized as expense when insured events occur over the coverage period of the policy.

This liability includes a provision for both reported claims (case reserves) and incurred but not reported claims (IBNR reserves). IBNR reserve estimates are generally calculated by first projecting the ultimate cost of all losses that have occurred (expected losses), and then subtracting paid losses, case reserves, and loss expenses. The methods of determining such estimates and establishing the resulting liability are reviewed regularly and any adjustments are reflected in income in the period in which they become known. Future developments may result in losses and loss expenses materially greater or less than recorded amounts.

Except for net unpaid loss and loss expense reserves of $26 million, net of discount, held at December 31, 2020, representing certain structured settlements for which the timing and amount of future claim payments are reliably determinable and $42 million, net of discount, of certain reserves for unsettled claims, Chubb does not discount its P&C loss reserves. This compares with reserves of $31 million for certain structured settlements and $43 million of certain reserves for unsettled claims at December 31, 2019. Structured settlements represent contracts purchased from life insurance companies primarily to settle workers' compensation claims, where payments to the claimant by the life insurance company are expected to be made in the form of an annuity. Chubb retains the liability to the claimant in the event that the life insurance company fails to pay. At December 31, 2020, the liability due to claimants was $548 million, net of discount, and reinsurance recoverables due from the life insurance companies was $522 million, net of discount. For structured settlement contracts where payments are guaranteed regardless of claimant life expectancy, the amounts recoverable from the life insurance companies at December 31, 2020 are included in Other assets in the Consolidated balance sheets, as they do not meet the requirements for reinsurance accounting.

Included in Unpaid losses and loss expenses are liabilities for asbestos and environmental (A&E) claims and expenses. These unpaid losses and loss expenses are principally related to claims arising from remediation costs associated with hazardous waste sites and bodily-injury claims related to asbestos products and environmental hazards. The estimation of these liabilities is particularly sensitive to changes in the legal environment including specific settlements that may be used as precedents to settle future claims. However, Chubb does not anticipate future changes in laws and regulations in setting its A&E reserve levels.

Also included in Unpaid losses and loss expenses is the fair value adjustment of $110 million and $145 million at December 31, 2020 and 2019, respectively, related to Chubb Corp’s historical unpaid losses and loss expenses. The estimated fair value consists of the present value of the expected net unpaid loss and loss adjustment expense payments adjusted for an estimated risk margin. The estimated cash flows are discounted at a risk free rate. The estimated risk margin varies based on the inherent risks associated with each type of reserve. The fair value is amortized through Amortization of purchased intangibles on the consolidated statements of operations through the year 2032, based on the estimated payout patterns of unpaid loss and loss expenses at the acquisition date.

Our loss reserves are presented net of contractual deductible recoverable amounts due from policyholders. Under the terms of certain high deductible policies which we offer, such as workers’ compensation and general liability, our customers are responsible to reimburse us for an agreed-upon dollar amount per claim. In nearly all cases we are required under such policies to pay covered claims first, and then seek reimbursement for amounts within the applicable deductible from our customers. We generally seek to mitigate this risk through collateral agreements.

Prior period development arises from changes to loss estimates recognized in the current year that relate to loss reserves first reported in previous calendar years and excludes the effect of losses from the development of earned premiums from previous accident years.

For purposes of analysis and disclosure, management views prior period development to be changes in the nominal value of loss estimates from period to period, net of premium and profit commission adjustments on loss sensitive contracts. Prior period development generally excludes changes in loss estimates that do not arise from the emergence of claims, such as those related to uncollectible reinsurance, interest, unallocated loss adjustment expenses, or foreign currency. Accordingly, specific items excluded from prior period development include the following: gains/losses related to foreign currency remeasurement; losses recognized from the early termination or commutation of reinsurance agreements that principally relate to the time value of money; changes in the value of reinsurance business assumed reflected in losses incurred but principally related to the time value of money; and losses that arise from changes in estimates of earned premiums from prior accident years. Except for foreign currency remeasurement, which is included in Net realized gains (losses), these items are included in current year losses.

i) Future policy benefits

The valuation of long-duration contract reserves requires management to make estimates and assumptions regarding expenses, mortality, persistency, and investment yields. Estimates are primarily based on historical experience and include a margin for

adverse deviation. Interest rates used in calculating reserves range from less than 1.0 percent to 9.0 percent at December 31, 2020 compared to less than 1.0 percent to 11.0 percent at December 31, 2019. Actual results could differ materially from these estimates. Management monitors actual experience and where circumstances warrant, will revise assumptions and the related reserve estimates. Revisions are recorded in the period they are determined.

Certain of our long-duration contracts are supported by assets that do not qualify for separate account reporting under GAAP. These assets are classified as non-qualified separate account assets and reported in Other investments and the offsetting liabilities are reported in Future policy benefits in the Consolidated balance sheets. Changes in the fair value of separate account assets that do not qualify for separate account reporting under GAAP are reported in Other income (expense) and the offsetting movements in the liabilities are included in Policy benefits in the Consolidated statements of operations.

j) Assumed reinsurance programs involving minimum benefit guarantees under variable annuity contracts

Chubb reinsures various death and living benefit guarantees associated with variable annuities issued primarily in the United States. We generally receive a monthly premium during the accumulation phase of the covered annuities (in-force) based on a percentage of either the underlying accumulated account values or the underlying accumulated guaranteed values. Depending on an annuitant's age, the accumulation phase can last many years. To limit our exposure under these programs, all reinsurance treaties include annual or aggregate claim limits and many include an aggregate deductible.

The guarantees which are payable on death, referred to as guaranteed minimum death benefits (GMDB), principally cover shortfalls between accumulated account value at the time of an annuitant's death and either i) an annuitant's total deposits; ii) an annuitant's total deposits plus a minimum annual return; or iii) the highest accumulated account value attained at any policy anniversary date. In addition, a death benefit may be based on a formula specified in the variable annuity contract that uses a percentage of the growth of the underlying contract value. Liabilities for GMDBs are based on cumulative assessments or premiums to date multiplied by a benefit ratio that is determined by estimating the present value of benefit payments and related adjustment expenses divided by the present value of cumulative assessment or expected premiums during the contract period.

Under reinsurance programs covering GLBs, we assume the risk of guaranteed minimum income benefits (GMIB) associated with variable annuity contracts. The GMIB risk is triggered if, at the time the contract holder elects to convert the accumulated account value to a periodic payment stream (annuitize), the accumulated account value is not sufficient to provide a guaranteed minimum level of monthly income. Our GLB reinsurance products meet the definition of a derivative for accounting purposes and are carried at fair value with changes in fair value recognized in Realized gains (losses) in the Consolidated statement of operations. Refer to Note 10 a) for additional information.

k) Deposit assets and liabilities

Deposit assets arise from ceded reinsurance contracts purchased that do not transfer significant underwriting or timing risk. Deposit liabilities include reinsurance deposit liabilities and contract holder deposit funds. The reinsurance deposit liabilities arise from contracts sold for which there is not a significant transfer of risk. Contract holder deposit funds represent a liability for investment contracts sold that do not meet the definition of an insurance contract, and certain of these contracts are sold with a guaranteed rate of return. Under deposit accounting, consideration received or paid is recorded as a deposit asset or liability in the balance sheet as opposed to recording premiums and losses in the statement of operations.

Interest income on deposit assets, representing the consideration received or to be received in excess of cash payments related to the deposit contract, is earned based on an effective yield calculation. The calculation of the effective yield is based on the amount and timing of actual cash flows at the balance sheet date and the estimated amount and timing of future cash flows. The effective yield is recalculated periodically to reflect revised estimates of cash flows. When a change in the actual or estimated cash flows occurs, the resulting change to the carrying amount of the deposit asset is reported as income or expense. Deposit assets of $107 million and $93 million at December 31, 2020 and 2019, respectively, are reflected in Other assets in the Consolidated balance sheets and the accretion of deposit assets related to interest pursuant to the effective yield calculation is reflected in Net investment income in the Consolidated statements of operations.

Deposit liabilities include reinsurance deposit liabilities of $86 million and $88 million and contract holder deposit funds of $2.2 billion and $2.0 billion at December 31, 2020 and 2019, respectively. Deposit liabilities are reflected in Accounts payable, accrued expenses, and other liabilities in the Consolidated balance sheets. At contract inception, the deposit liability equals net cash received. An accretion rate is established based on actuarial estimates whereby the deposit liability is increased to the estimated amount payable over the contract term. The deposit accretion rate is the rate of return required to fund expected future payment obligations. We periodically reassess the estimated ultimate liability and related expected rate of

return. Changes to the deposit liability are generally reflected through Interest expense to reflect the cumulative effect of the period the contract has been in force, and by an adjustment to the future accretion rate of the liability over the remaining estimated contract term.

The liability for contract holder deposit funds equals accumulated policy account values, which consist of the deposit payments plus credited interest less withdrawals and amounts assessed through the end of the period.

l) Property and Equipment

Property and equipment used in operations are capitalized and carried at cost less accumulated depreciation and are reported within Other assets in the Consolidated balance sheets. At December 31, 2020, property and equipment totaled $2.0 billion, consisting principally of capitalized software costs of $1.3 billion incurred to develop or obtain computer software for internal use and company-owned facilities of $260 million. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets. For capitalized software, the estimated useful life is generally three to five years, but can be as long as 15 years and for company-owned facilities the estimated useful life is 40 years. At December 31, 2019, property and equipment totaled $1.9 billion.

m) Foreign currency remeasurement and translation

The functional currency for each of our foreign operations is generally the currency of the local operating environment. Transactions in currencies other than a foreign operation's functional currency are remeasured into the functional currency, and the resulting foreign exchange gains and losses are reflected in Net realized gains (losses) in the Consolidated statements of operations. Functional currency assets and liabilities are translated into the reporting currency, U.S. dollars, using period end exchange rates and the related translation adjustments are recorded as a separate component of AOCI in Shareholders' equity. Functional statement of operations amounts expressed in functional currencies are translated using average exchange rates.

n) Administrative expenses

Administrative expenses generally include all operating costs other than policy acquisition costs. The North America Commercial P&C Insurance segment manages and uses an in-house third-party claims administrator, ESIS Inc. (ESIS). ESIS performs claims management and risk control services for domestic and international organizations that self-insure P&C exposures as well as internal P&C exposures. The net operating income of ESIS is included within Administrative expenses in the Consolidated statements of operations and were $18 million, $47 million, and $49 million for the years ended December 31, 2020, 2019, and 2018, respectively.

o) Income taxes

Income taxes have been recorded related to those operations subject to income tax. Deferred tax assets and liabilities result from temporary differences between the amounts recorded in the Consolidated Financial Statements and the tax basis of our assets and liabilities. The effect on deferred tax assets and liabilities of a change in tax law or rates is recognized in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if it is more likely than not that all, or some portion, of the benefits related to these deferred tax assets will not be realized. The valuation allowance assessment considers tax planning strategies, where appropriate.

We recognize uncertain tax positions that are determined to be more likely than not of being sustained upon examination. Recognized income tax positions are measured at the largest amount that has a greater than 50 percent likelihood of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs.

p) Earnings per share

Basic earnings per share is calculated using the weighted-average shares outstanding, including participating securities with non-forfeitable rights to dividends such as unvested restricted stock. All potentially dilutive securities, including stock options are excluded from the basic earnings per share calculation. In calculating diluted earnings per share, the weighted-average shares outstanding is increased to include all potentially dilutive securities. Basic and diluted earnings per share are calculated by dividing net income by the applicable weighted-average number of shares outstanding during the year.

q) Share-based compensation

Chubb measures and records compensation cost for all share-based payment awards at grant-date fair value. Compensation costs are recognized for vesting of share-based payment awards with only service conditions on a straight-line basis over the requisite service period for each separately vesting portion of the award as if the award were, in substance, multiple awards. For retirement-eligible participants, compensation costs for certain share-based payment awards are recognized immediately at the date of grant. Refer to Note 12 for additional information.

r) Chubb integration expenses

Direct costs related to the Chubb Corp acquisition were expensed as incurred. Chubb integration expenses were nil, $23 million, and $59 million for the years ended December 31, 2020, 2019 and 2018, respectively, and include all internal and external costs directly related to the integration activities of the Chubb Corp acquisition. These expenses principally consisted of personnel-related expenses, consulting fees, and rebranding.

s) New accounting pronouncements

Adopted in 2020

Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments

Effective January 1, 2020, we adopted, on a modified retrospective basis, new guidance on the accounting for credit losses of financial instruments that are measured at amortized cost, including held to maturity securities, and reinsurance recoverables, by applying an approach based on the current expected credit losses (CECL). The estimate of expected credit losses considers historical information, current information, as well as reasonable and supportable forecasts, including estimates of prepayments. In addition, the guidance also replaced the current available for sale (AFS) security other-than-temporary impairment model by requiring an estimate of the expected credit loss (ECL) only when the fair value is below the amortized cost of the asset. The length of time the fair value of an AFS security has been below its amortized cost no longer impacts the determination of whether a potential credit loss exists. The AFS security model also requires the use of a valuation allowance as compared to the previous practice of writing down the asset.

In 2020, we recognized a cumulative effect adjustment and decreased beginning retained earnings by $79 million pre-tax, or $72 million after-tax, principally related to the valuation allowance for credit losses. We also adopted the required disclosures within Note 3 Investments and Note 5 Reinsurance. Results for reporting periods prior to January 1, 2020 are presented in accordance with the previous guidance.

Adopted in 2021

Income Taxes - Simplifying the Accounting for Income Taxes

Effective January 1, 2021, we adopted guidance which is intended to simplify the accounting for income taxes by removing several exceptions contained in existing guidance and amending other guidance. The adoption of the new guidance did not have a material effect on our results of operations or financial condition.

Accounting guidance not yet adopted

Effects of Reference Rate Reform on Financial Reporting

In March 2020, the FASB issued guidance which provides optional expedients and exceptions for applying GAAP to investments, derivatives, or other transactions that reference the London Interbank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of reference rate reform. Along with the optional expedients, the amendments include a general principle that permits an entity to consider contract modifications due to reference reform to be an event that does not require contract re-measurement at the modification date or reassessment of a previous accounting determination. Additionally, a company may make a one-time election to sell, transfer, or both sell and transfer debt securities classified as held to maturity that reference a rate affected by reference rate reform and that were classified as held to maturity before January 1, 2020. This standard may be elected over time through December 31, 2022 as reference rate reform activities occur. Our exposure to LIBOR is limited and, accordingly, we do not expect reference rate reform to have a material impact on our Consolidated Financial Statements.

Targeted Improvements to the Accounting for Long-Duration Contracts

In August 2018, the FASB issued guidance to improve the existing recognition, measurement, presentation, and disclosure requirements for long-duration contracts issued by an insurance entity. The amendments in this update require more frequent updating of assumptions and a standardized discount rate for the future policy benefit liability, a requirement to use the fair value measurement model for policies with market risk benefits, simplified amortization of deferred acquisition costs, and enhanced disclosures. This standard will be effective in the first quarter of 2023 with early adoption permitted. We are currently assessing the effect of adopting this guidance on our financial condition and results of operations. We will be better able to quantify the effect of adopting this standard as we progress in our implementation process and draw nearer to the date of adoption.

Acquisitions (Notes)	12 Months Ended
Acquisitions (Notes)	Dec. 31, 2020
Acquisitions [Abstract]
Mergers, Acquisitions and Dispositions Disclosures [Text Block]	Acquisitions Huatai Group Chubb maintains a direct investment in Huatai Insurance Group Co., Ltd. (Huatai Group). Huatai Group is the parent company of, and owns 100 percent of, Huatai Property & Casualty Insurance Co., Ltd. (Huatai P&C), approximately 80 percent of Huatai Life Insurance Co., Ltd. (Huatai Life), and approximately 82 percent of Huatai Asset Management Co., Ltd. (collectively, Huatai). Huatai Group's insurance operations have more than 600 branches and 11 million customers in China. In 2019, Chubb entered into agreements to acquire an additional 22.4 percent ownership in Huatai Group through two separate purchases, a 15.3 percent ownership interest for approximately $1.1 billion and a 7.1 percent ownership interest for approximately $493 million. On July 13, 2020, we completed the 15.3 percent purchase. The purchase of the additional 7.1 percent ownership interest is contingent upon important conditions. In connection with these purchase agreements, we paid $1.6 billion, including a collateralized deposit for the 7.1 percent tranche, in 2020. These transactions are recorded within investing activities on the Consolidated statement of cash flows. Separately, in November 2020, we completed the purchase of an incremental 0.9 percent ownership interest in Huatai Group for approximately $65 million. As of December 31, 2020, Chubb's aggregate ownership interest in Huatai Group was approximately 47.1 percent. Chubb applies the equity method of accounting to its investment in Huatai Group by recording its share of net income or loss in Other (income) expense in the Consolidated statements of operations. Refer to Note 14 for additional information. The Consolidated statements of operations include the equity income from the additional ownership interests as of each respective closing date. Upon completion of the 7.1 percent purchase, which will result in majority ownership of Huatai Group, Chubb is expected to obtain control of Huatai. At that time, Chubb is expected to apply consolidation accounting and discontinue the application of the equity method of accounting. Prior year acquisition Banchile Seguros de Vida On December 30, 2019, we acquired Banchile Seguros de Vida, an insurance company providing both life and property and casualty coverages in Chile, for $74 million in cash. The results of this acquisition are included in the Overseas General Insurance and Life Insurance segments as appropriate, determined by the type of policy written.

Investments

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

a) Fixed maturities

Effective January 1, 2020, we adopted new accounting guidance that requires a valuation allowance for credit losses to be established for fixed maturity securities classified as held to maturity (HTM) or available for sale (AFS).


December 31, 2020	Amortized Cost		Valuation Allowance		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	2,471	$	—	$	199	$	—	$	2,670
Non-U.S.	24,594		(6)		1,808		(42)		26,354
Corporate and asset-backed securities	34,095		(14)		2,322		(72)		36,331
Mortgage-backed securities	17,456		—		1,022		(8)		18,470
Municipal	6,572		—		304		(2)		6,874
	$	85,188	$	(20)	$	5,655	$	(124)	$	90,699
	Amortized Cost		Valuation Allowance		Net Carrying Value		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
Held to maturity
U.S. Treasury / Agency	$	1,392	$	—	$	1,392	$	60	$	—	$	1,452
Non-U.S.	1,295		(7)		1,288		118		(1)		1,405
Corporate and asset-backed securities	2,185		(35)		2,150		288		—		2,438
Mortgage-backed securities	2,000		(1)		1,999		148		(1)		2,146
Municipal	4,825		(1)		4,824		245		—		5,069
	$	11,697	$	(44)	$	11,653	$	859	$	(2)	$	12,510


December 31, 2019	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value		OTTI Recognized in AOCI
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	3,188	$	96	$	(1)	$	3,283	$	—
Non-U.S.	22,670		1,099		(62)		23,707		(25)
Corporate and asset-backed securities	30,689		1,180		(78)		31,791		(5)
Mortgage-backed securities	18,712		494		(14)		19,192		—
Municipal	7,321		205		(11)		7,515		—
	$	82,580	$	3,074	$	(166)	$	85,488	$	(30)
Held to maturity
U.S. Treasury / Agency	$	1,318	$	29	$	—	$	1,347	$	—
Non-U.S.	1,423		62		—		1,485		—
Corporate and asset-backed securities	2,349		121		(2)		2,468		—
Mortgage-backed securities	2,331		65		—		2,396		—
Municipal	5,160		150		(1)		5,309		—
	$	12,581	$	427	$	(3)	$	13,005	$	—

The following table presents the amortized cost of our HTM securities according to S&P rating:


December 31, 2020
(in millions of U.S. dollars)	Amortized cost		% of Total
AAA	$	2,511	22	%
AA	6,193		53	%
A	2,138		18	%
BBB	826		7	%
BB	28		—	%
Other	1		—	%
Total	$	11,697	100	%

The following table presents fixed maturities by contractual maturity:


	December 31				December 31
			2020				2019
(in millions of U.S. dollars)	Net Carrying Value		Fair Value		Amortized Cost		Fair Value
Available for sale
Due in 1 year or less	$	4,760	$	4,760	$	3,951	$	3,973
Due after 1 year through 5 years	26,227		26,227		27,142		27,720
Due after 5 years through 10 years	27,232		27,232		23,901		24,874
Due after 10 years	14,010		14,010		8,874		9,729
	72,229		72,229		63,868		66,296
Mortgage-backed securities	18,470		18,470		18,712		19,192
	$	90,699	$	90,699	$	82,580	$	85,488
Held to maturity
Due in 1 year or less	$	1,231	$	1,240	$	478	$	479
Due after 1 year through 5 years	3,592		3,760		3,869		3,940
Due after 5 years through 10 years	3,029		3,228		3,756		3,883
Due after 10 years	1,802		2,136		2,147		2,307
	9,654		10,364		10,250		10,609
Mortgage-backed securities	1,999		2,146		2,331		2,396
	$	11,653	$	12,510	$	12,581	$	13,005

Expected maturities could differ from contractual maturities because borrowers may have the right to call or prepay obligations, with or without call or prepayment penalties.

b) Gross unrealized loss

Fixed maturities in an unrealized loss position at December 31, 2020, comprised both investment grade and below investment grade securities for which fair value declined primarily due to widening credit spreads since the date of purchase.

The following table presents, for AFS fixed maturities in an unrealized loss position (including securities on loan) that are not deemed to have credit losses, the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position:


	0 – 12 Months				Over 12 Months				Total
December 31, 2020	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)

Non-U.S.	$	1,628	$	(35)	$	114	$	(5)	$	1,742	$	(40)
Corporate and asset-backed securities	2,212		(33)		593		(14)		2,805		(47)
Mortgage-backed securities	875		(6)		35		(2)		910		(8)
Municipal	40		(1)		16		(1)		56		(2)
Total AFS fixed maturities	$	4,755	$	(75)	$	758	$	(22)	$	5,513	$	(97)

The following table presents, for all securities in an unrealized loss position (including securities on loan), the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position:


	0 – 12 Months				Over 12 Months				Total
December 31, 2019	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)
U.S. Treasury / Agency	$	234	$	(1)	$	339	$	—	$	573	$	(1)
Non-U.S.	1,846		(34)		802		(28)		2,648		(62)
Corporate and asset-backed securities	2,121		(40)		988		(40)		3,109		(80)
Mortgage-backed securities	1,174		(6)		932		(8)		2,106		(14)
Municipal	188		—		276		(12)		464		(12)
Total fixed maturities	$	5,563	$	(81)	$	3,337	$	(88)	$	8,900	$	(169)

c) Net realized gains (losses)

The following table presents a roll-forward of pre-tax credit losses related to fixed maturities for which a portion of OTTI was recognized in OCI:


	Year Ended December 31
(in millions of U.S. dollars)	2019		2018
Balance of credit losses related to securities still held – beginning of year	$	34	$	22
Additions where no OTTI was previously recorded	33		20
Additions where an OTTI was previously recorded	4		5
Reductions for securities sold during the period	(41)		(13)
Balance of credit losses related to securities still held – end of year	$	30	$	34

The following table presents the components of Net realized gains (losses) and the change in net unrealized appreciation (depreciation) of investments:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Fixed maturities:
OTTI on fixed maturities, gross	$	—	$	(90)	$	(52)
OTTI on fixed maturities recognized in OCI (pre-tax)	—		32		3
OTTI on fixed maturities, net	—		(58)		(49)
Gross realized gains excluding OTTI	244		203		334
Gross realized losses excluding OTTI	(366)		(176)		(587)
Recovery of expected credit losses	11		—		—
Impairment (1)	(170)		—		—
Total fixed maturities	(281)		(31)		(302)
Equity securities	586		104		(59)

Other investments	(32)		(20)		(5)
Foreign exchange gains (losses)	(483)		7		131
Investment and embedded derivative instruments	81		(435)		(75)
Fair value adjustments on insurance derivative	(202)		(4)		(248)
S&P futures	(108)		(138)		(4)
Other derivative instruments	1		(8)		(3)
Other	(60)		(5)		(87)
Net realized gains (losses) (pre-tax)	$	(498)	$	(530)	$	(652)

Change in net unrealized appreciation (depreciation) on investments (pre-tax):
Fixed maturities available for sale	$	2,628	$	3,769	$	(1,958)
Fixed maturities held to maturity	(24)		(31)		(38)

Other	(12)		(3)		—
Income tax (expense) benefit	(462)		(647)		297
Change in net unrealized appreciation (depreciation) on investments (after-tax)	$	2,130	$	3,088	$	(1,699)

(1)Relates to certain securities we intended to sell and securities written to market entering default.

Realized gains and losses from Equity securities and Other investments from the table above include sales of securities and unrealized gains and losses from fair value changes as follows:


	Year Ended December 31, 2020						Year Ended December 31, 2019						Year Ended December 31, 2018
(in millions of U.S. dollars)	Equity Securities		Other Investments		Total		Equity Securities		Other Investments		Total		Equity Securities		Other Investments		Total
Net gains (losses) recognized during the period	$	586	$	(32)	$	554	$	104	$	(20)	$	84	$	(59)	$	(5)	$	(64)
Less: Net gains (losses) recognized from sales of securities	455		—		455		58		(5)		53		70		121		191
Unrealized gains (losses) recognized for securities still held at reporting date	$	131	$	(32)	$	99	$	46	$	(15)	$	31	$	(129)	$	(126)	$	(255)

The following table presents a roll-forward of valuation allowance for expected credit losses on fixed maturities:


	Year Ended
	December 31
(in millions of U.S. dollars)	2020
Available for sale
Valuation allowance for expected credit losses - beginning of period	$	—
Impact of adoption of new accounting guidance	25
Provision for expected credit loss	188
Initial allowance for purchased securities with credit deterioration	5
Write-offs charged against the expected credit loss	(5)
Recovery of expected credit loss	(193)
Valuation allowance for expected credit losses - end of period	$	20
Held to maturity
Valuation allowance for expected credit losses - beginning of period	$	—
Impact of adoption of new accounting guidance	44
Provision for expected credit loss	9


Recovery of expected credit loss	(9)
Valuation allowance for expected credit losses - end of period	$	44

Purchased Credit Deterioration (PCD) Securities

During the year ended December 31, 2020, we purchased $108 million of securities with credit deterioration, categorized as available for sale, and assessed an allowance for expected credit losses of $5 million at acquisition. These PCD securities had a par value at acquisition of $144 million.

d) Other investments


	December 31
(in millions of U.S. dollars)	2020		2019
Alternative investments:
Partially-owned investment companies	$	5,969	$	4,142
Limited partnerships	547		508
Investment funds	254		271
Alternative investments	6,770		4,921
Life insurance policies	438		377
Policy loans	233		247
Non-qualified separate account assets (1)	316		283
Other	188		234
Total	$	7,945	$	6,062

(1)Non-qualified separate account assets are comprised of mutual funds, supported by assets that do not qualify for separate account reporting under GAAP.

Alternative investments

Alternative investments include partially-owned investment companies, investment funds, and limited partnerships measured at fair value using net asset value (NAV) as a practical expedient. The following table presents, by investment category, the expected liquidation period, fair value, and maximum future funding commitments of alternative investments:


		December 31				December 31
		2020				2019
(in millions of U.S. dollars)	Expected Liquidation Period of Underlying Assets	Fair Value		Maximum Future Funding Commitments		Fair Value		Maximum Future Funding Commitments
Financial	2 to 10 Years	$	673	$	237	$	611	$	329
Real Assets	2 to 11 Years	805		598		712		422
Distressed	2 to 8 Years	358		970		263		80
Private Credit	3 to 8 Years	88		270		104		272
Traditional	2 to 14 Years	4,519		1,125		2,844		2,160
Vintage	1 to 2 Years	73		—		116		—
Investment funds	Not Applicable	254		—		271		—
		$	6,770	$	3,200	$	4,921	$	3,263

Included in all categories in the above table, except for Investment funds, are investments for which Chubb will never have the contractual option to redeem but receives distributions based on the liquidation of the underlying assets. Further, for all categories except for Investment funds, Chubb does not have the ability to sell or transfer the investments without the consent from the general partner of individual funds.


Investment Category						Consists of investments in private equity funds:
Financial						targeting financial services companies, such as financial institutions and insurance services worldwide
Real Assets						targeting investments related to hard physical assets, such as real estate, infrastructure and natural resources
Distressed						targeting distressed corporate debt/credit and equity opportunities in the U.S.
Private Credit						targeting privately originated corporate debt investments, including senior secured loans and subordinated bonds
Traditional						employing traditional private equity investment strategies such as buyout and growth equity globally
Vintage						funds where the initial fund term has expired

Included in partially-owned investment companies and limited partnerships are 130 individual limited partnerships covering a broad range of investment strategies including large cap buyouts, specialist buyouts, growth capital, distressed, mezzanine, real estate, and co-investments. The underlying portfolio consists of various public and private debt and equity securities of publicly traded and privately held companies and real estate assets. The underlying investments across various partnerships, geographies, industries, asset types, and investment strategies provide risk diversification within the limited partnership portfolio and the overall investment portfolio.

Investment funds employ various investment strategies such as long/short equity and arbitrage/distressed. Included in this category are investments for which Chubb has the option to redeem at agreed upon value as described in each investment fund’s subscription agreement. Depending on the terms of the various subscription agreements, investment fund investments may be redeemed monthly, quarterly, semi-annually, or annually. If Chubb wishes to redeem an investment fund investment, it must first determine if the investment fund is still in a lock-up period (a time when Chubb cannot redeem its investment so that the investment fund manager has time to build the portfolio). If the investment fund is no longer in its lock-up period, Chubb must then notify the investment fund manager of its intention to redeem by the notification date prescribed by the subscription agreement. Subsequent to notification, the investment fund can redeem Chubb’s investment within several months of the notification. Notice periods for redemption of the investment funds are up to 270 days. Chubb can redeem its investment funds without consent from the investment fund managers.

e) Investments in partially-owned insurance companies

The following table presents Investments in partially-owned insurance companies:


	December 31, 2020						December 31, 2019
(in millions of U.S. dollars, except for percentages)	Carrying Value		Goodwill		Direct Ownership Percentage		Carrying Value		Goodwill		Direct Ownership Percentage		Domicile
Huatai Group	$	2,461	$	1,313	47	%	$	1,053	$	460	31	%	China
Huatai Life Insurance Company	201		69		20	%	147		64		20	%	China
Freisenbruch-Meyer	10		3		40	%	10		3		40	%	Bermuda
Chubb Arabia Cooperative Insurance Company	23		—		30	%	20		—		30	%	Saudi Arabia
Russian Reinsurance Company	4		—		23	%	2		—		23	%	Russia
ABR Reinsurance Ltd.	114		—		16	%	100		—		12	%	Bermuda

Total	$	2,813	$	1,385			$	1,332	$	527

Chubb’s aggregate direct and indirect ownership in Huatai Life is approximately 57.5 percent, comprising 20 percent direct and 37.5 percent indirect ownership interest.

The table above excludes the 7.1 percent of additional ownership commitment in Huatai Group that is contingent upon important conditions. Refer to Note 2 for additional information.

f) Net investment income


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Fixed maturities (1)	$	3,321	$	3,385	$	3,128
Short-term investments	48		84		90
Other interest income	19		25		118
Equity securities	81		26		33
Other investments	82		78		104
Gross investment income (1)	3,551		3,598		3,473
Investment expenses	(176)		(172)		(168)
Net investment income (1)	$	3,375	$	3,426	$	3,305
(1) Includes amortization expense related to fair value adjustment of acquired invested assets related to the Chubb Corp acquisition	$	(116)	$	(161)	$	(248)

g) Restricted assets

Chubb is required to maintain assets on deposit with various regulatory authorities to support its insurance and reinsurance operations. These requirements are generally promulgated in the statutory regulations of the individual jurisdictions. The assets on deposit are available to settle insurance and reinsurance liabilities. Chubb is also required to restrict assets pledged under repurchase agreements, which represent Chubb's agreement to sell securities and repurchase them at a future date for a predetermined price. We use trust funds in certain large reinsurance transactions where the trust funds are set up for the benefit of the ceding companies and generally take the place of letter of credit (LOC) requirements. We have investments in segregated portfolios primarily to provide collateral or guarantees for LOC and derivative transactions. Included in restricted assets are investments, primarily fixed maturities, totaling $19.6 billion and $21.0 billion, and cash of $89 million and $109 million, at December 31, 2020 and 2019, respectively.

The following table presents the components of restricted assets:


	December 31		December 31
(in millions of U.S. dollars)	2020		2019
Trust funds	$	12,305	$	14,004
Deposits with U.S. regulatory authorities	2,438		2,466
Deposits with non-U.S. regulatory authorities	2,905		2,709
Assets pledged under repurchase agreements	1,462		1,464
Other pledged assets	584		490
Total	$	19,694	$	21,133

Fair value measurements

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Fair value measurements

a) Fair value hierarchy

Fair value of financial assets and financial liabilities is estimated based on the framework established in the fair value accounting guidance. The guidance defines fair value as the price to sell an asset or transfer a liability (an exit price) in an orderly transaction between market participants and establishes a three-level valuation hierarchy based on the reliability of the inputs. The fair value hierarchy gives the highest priority to quoted prices in active markets and the lowest priority to unobservable data.

The three levels of the hierarchy are as follows:

•Level 1 – Unadjusted quoted prices for identical assets or liabilities in active markets;

•Level 2 – Includes, among other items, inputs other than quoted prices that are observable for the asset or liability such as

interest rates and yield curves, quoted prices for similar assets and liabilities in active markets, and quoted prices for identical or similar assets and liabilities in markets that are not active; and

•Level 3 – Inputs that are unobservable and reflect management’s judgments about assumptions that market participants

would use in pricing an asset or liability.

We categorize financial instruments within the valuation hierarchy at the balance sheet date based upon the lowest level of inputs that are significant to the fair value measurement.

We use pricing services to obtain fair value measurements for the majority of our investment securities. Based on management’s understanding of the methodologies used, these pricing services only produce an estimate of fair value if there is observable market information that would allow them to make a fair value estimate. Based on our understanding of the market inputs used by the pricing services, all applicable investments have been valued in accordance with GAAP. We do not adjust prices obtained from pricing services. The following is a description of the valuation techniques and inputs used to determine fair values for financial instruments carried at fair value, as well as the general classification of such financial instruments pursuant to the valuation hierarchy.

Fixed maturities

We use pricing services to estimate fair value measurements for the majority of our fixed maturities. The pricing services use market quotations for fixed maturities that have quoted prices in active markets; such securities are classified within Level 1. For fixed maturities other than U.S. Treasury securities that generally do not trade on a daily basis, the pricing services prepare estimates of fair value measurements using their pricing applications or pricing models, which include available relevant market information, benchmark curves, benchmarking of like securities, sector groupings, and matrix pricing. Additional valuation factors that can be taken into account are nominal spreads, dollar basis, and liquidity adjustments. The pricing services evaluate each asset class based on relevant market and credit information, perceived market movements, and sector news. The market inputs used in the pricing evaluation, listed in the approximate order of priority include: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, reference data, and industry and economic events. The extent of the use of each input is dependent on the asset class and the market conditions. Given the asset class, the priority of the use of inputs may change, or some market inputs may not be relevant. Additionally, fixed maturities valuation is more subjective when markets are less liquid due to the lack of market based inputs (i.e., stale pricing) and may require the use of models to be priced. The lack of market based inputs may increase the potential that an investment's estimated fair value is not reflective of the price at which an actual transaction would occur. The overwhelming majority of fixed maturities are classified within Level 2 because the most significant inputs used in the pricing techniques are observable. For a

small number of fixed maturities, we obtain a single broker quote (typically from a market maker). Due to the disclaimers on the quotes that indicate that the price is indicative only, we include these fair value estimates in Level 3.

Equity securities

Equity securities with active markets are classified within Level 1 as fair values are based on quoted market prices. For equity securities in markets which are less active, fair values are based on market valuations and are classified within Level 2. Equity securities for which pricing is unobservable are classified within Level 3.

Short-term investments

Short-term investments, which comprise securities due to mature within one year of the date of purchase that are traded in active markets, are classified within Level 1 as fair values are based on quoted market prices. Securities such as commercial paper and discount notes are classified within Level 2 because these securities are typically not actively traded due to their approaching maturity, and as such, their cost approximates fair value. Short-term investments for which pricing is unobservable are classified within Level 3.

Other investments

Fair values for the majority of Other investments including investments in partially-owned investment companies, investment funds, and limited partnerships are based on their respective net asset values or equivalent (NAV) and are excluded from the fair value hierarchy table below. Certain of our long-duration contracts are supported by assets that do not qualify for separate account reporting under GAAP. These assets comprise mutual funds, classified within Level 1 in the valuation hierarchy on the same basis as other equity securities traded in active markets. Other investments also include equity securities, classified within Level 1 and fixed maturities, classified within Level 2, held in rabbi trusts maintained by Chubb for deferred compensation plans and supplemental retirement plans and are classified within the valuation hierarchy on the same basis as other equity securities and fixed maturities. Other investments for which pricing is unobservable are classified within Level 3.

Securities lending collateral

The underlying assets included in Securities lending collateral in the Consolidated balance sheets are fixed maturities which are classified in the valuation hierarchy on the same basis as other fixed maturities. Excluded from the valuation hierarchy is the corresponding liability related to Chubb’s obligation to return the collateral plus interest as it is reported at contract value and not fair value in the Consolidated balance sheets.

Investment derivative instruments

Actively traded investment derivative instruments, including futures, options, and forward contracts are classified within Level 1 as fair values are based on quoted market prices. The fair value of cross-currency swaps and interest rate swaps is based on market valuations and is classified within Level 2. Investment derivative instruments are recorded in either Other assets or Accounts payable, accrued expenses, and other liabilities in the Consolidated balance sheets.

Other derivative instruments

We maintain positions in exchange-traded equity futures contracts designed to limit exposure to a severe equity market decline, which would cause an increase in expected claims and, therefore, an increase in future policy benefit reserves for our guaranteed minimum death benefits (GMDB) and an increase in the fair value liability for our guaranteed living benefits (GLB) reinsurance business. Our positions in exchange-traded equity futures contracts are classified within Level 1. The fair value of the majority of the remaining positions in other derivative instruments is based on significant observable inputs including equity security and interest rate indices. Accordingly, these are classified within Level 2. Other derivative instruments based on unobservable inputs are classified within Level 3. Other derivative instruments are recorded in either Other assets or Accounts payable, accrued expenses, and other liabilities in the Consolidated balance sheets.

Separate account assets

Separate account assets represent segregated funds where investment risks are borne by the customers, except to the extent of certain guarantees made by Chubb. Separate account assets comprise mutual funds classified within Level 1 in the valuation hierarchy on the same basis as other equity securities traded in active markets. Separate account assets also include fixed maturities classified within Level 2 because the most significant inputs used in the pricing techniques are observable. Excluded from the valuation hierarchy are the corresponding liabilities as they are reported at contract value and not fair value in the Consolidated balance sheets. Separate account assets are recorded in Other assets in the Consolidated balance sheets.

Guaranteed living benefits

The GLB arises from life reinsurance programs covering living benefit guarantees whereby we assume the risk of guaranteed minimum income benefits (GMIB) associated with variable annuity contracts. GLB’s are recorded in Accounts payable, accrued expenses, and other liabilities in the Consolidated balance sheets. Prior to 2020, a portion of the GLB liability that represented expected losses allocated to premiums received was recorded as incurred losses within Future policy benefits, with changes in these estimates recorded in Future policy benefits. We reclassified $441 million, $409 million, and $346 million of GLB liability as of December 31, 2019, 2018, and 2017, respectively, to Accounts payable, accrued expenses, and other liabilities in the Consolidated balance sheets to conform with the new presentation. For GLB reinsurance, Chubb estimates fair value using an internal valuation model which includes current market information and estimates of policyholder behavior. All of the treaties contain claim limits, which are factored into the valuation model. The fair value depends on a number of factors, including interest rates, equity markets, credit risk, current account value, market volatility, expected annuitization rates and other policyholder behavior, and changes in policyholder mortality. Because of the significant use of unobservable inputs including policyholder behavior, GLB reinsurance is classified within Level 3.

Financial instruments measured at fair value on a recurring basis, by valuation hierarchy


December 31, 2020	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)
Assets:
Fixed maturities available for sale
U.S. Treasury / Agency	$	2,148	$	522	$	—	$	2,670
Non-U.S.	—		25,808		546		26,354
Corporate and asset-backed securities	—		34,758		1,573		36,331
Mortgage-backed securities	—		18,410		60		18,470
Municipal	—		6,874		—		6,874
	2,148		86,372		2,179		90,699
Equity securities	3,954		—		73		4,027
Short-term investments	2,866		1,474		5		4,345
Other investments (1)	434		438		10		882
Securities lending collateral	—		1,844		—		1,844
Investment derivative instruments	35		—		—		35

Separate account assets	4,264		124		—		4,388
Total assets measured at fair value (1)	$	13,701	$	90,252	$	2,267	$	106,220
Liabilities:
Investment derivative instruments	$	52	$	—	$	—	$	52
Other derivative instruments	17		—		—		17
GLB (2)	—		—		1,089		1,089
Total liabilities measured at fair value	$	69	$	—	$	1,089	$	1,158

(1)Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $6,770 million, policy loans of $233 million and other investments of $60 million at December 31, 2020 measured using NAV as a practical expedient.

(2)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.


December 31, 2019	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)
Assets:
Fixed maturities available for sale
U.S. Treasury / Agency	$	2,664	$	619	$	—	$	3,283
Non-U.S.	—		23,258		449		23,707
Corporate and asset-backed securities	—		30,340		1,451		31,791
Mortgage-backed securities	—		19,132		60		19,192
Municipal	—		7,515		—		7,515
	2,664		80,864		1,960		85,488
Equity securities	728		15		69		812
Short-term investments	2,803		1,482		6		4,291
Other investments (1)	412		377		10		799
Securities lending collateral	—		994		—		994
Investment derivative instruments	24		—		—		24
Other derivative instruments	2		—		—		2
Separate account assets	3,437		136		—		3,573
Total assets measured at fair value (1)	$	10,070	$	83,868	$	2,045	$	95,983
Liabilities:
Investment derivative instruments	$	93	$	—	$	—	$	93
Other derivative instruments	13		—		—		13

GLB (2)	—		—		897		897
Total liabilities measured at fair value	$	106	$	—	$	897	$	1,003

(1)Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,921 million and other investments of $95 million at December 31, 2019 measured using NAV as a practical expedient.

(2)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

Level 3 financial instruments

The following table presents the significant unobservable inputs used in the Level 3 liability valuations. Excluded from the table below are inputs used to determine the fair value of Level 3 assets which are based on single broker quotes and contain no quantitative unobservable inputs developed by management. The majority of our fixed maturities classified as Level 3 used external pricing when markets are less liquid due to the lack of market inputs (i.e., stale pricing, broker quotes).


(in millions of U.S. dollars, except for percentages)	Fair Value at December 31 2020		Valuation Technique	Significant Unobservable Inputs	Ranges	Weighted Average (1)
GLB (1)	$	1,089	Actuarial model	Lapse rate	3% - 34%	4.7	%
				Annuitization rate	0% - 100%	3.6	%

(1)The weighted average lapse and annuitization rates are determined by weighting each treaty's rates by the GLB contracts fair value.

The most significant policyholder behavior assumptions include lapse rates and the GMIB annuitization rates. Assumptions regarding lapse rates and GMIB annuitization rates differ by treaty, but the underlying methodologies to determine rates applied to each treaty are comparable.

A lapse rate is the percentage of in-force policies surrendered in a given calendar year. All else equal, as lapse rates increase, ultimate claim payments will decrease. In general, the base lapse function assumes low lapse rates during the surrender charge period of the GMIB contract, followed by a “spike” lapse rate in the year immediately following the surrender charge period, and then reverting to an ultimate lapse rate, typically over a 2-year period. This base rate is adjusted downward for policies with more valuable guarantees (policies with guaranteed values far in excess of their account values). Partial withdrawals and the impact of older policyholders with tax-qualified contracts (due to required minimum distributions) are also reflected in our modeling.

The GMIB annuitization rate is the percentage of policies for which the policyholder will elect to annuitize using the guaranteed benefit provided under the GMIB. All else equal, as GMIB annuitization rates increase, ultimate claim payments will increase, subject to treaty claim limits. All GMIB reinsurance treaties include claim limits to protect Chubb in the event that actual annuitization behavior is significantly higher than expected. In general, Chubb assumes that GMIB annuitization rates will be higher for policies with more valuable guarantees (policies with guaranteed values far in excess of their account values). Chubb also assumes that GMIB annuitization rates increase as policyholders get older. In addition, we also assume that GMIB annuitization rates are higher in the first year immediately following the waiting period (the first year the policies are eligible to annuitize using the GMIB) in comparison to all subsequent years. We do not yet have fully credible annuitization experience for all clients.

The effect of changes in key market factors on assumed lapse and annuitization rates reflect emerging trends using data available from cedants. For treaties with limited experience, rates are established in line with data received from other ceding companies adjusted, as appropriate, with industry estimates. The model and related assumptions are regularly re-evaluated by management and enhanced, as appropriate, based upon additional experience obtained related to policyholder behavior and availability of updated information such as market conditions, market participant assumptions, and demographics of in-force annuities. In the fourth quarter of 2020, we completed a review of policyholder behavior related to annuitizations, partial withdrawals, lapses, and mortality for our variable annuity reinsurance business. As a result, we refined our policyholder behavior assumptions (mainly those relating to annuitizations and partial withdrawals), which had an insignificant impact on net income. During the year ended December 31, 2020, we also made routine model refinements to the internal valuation model which had an insignificant impact on net income.

The following tables present a reconciliation of the beginning and ending balances of financial instruments measured at fair value using significant unobservable inputs (Level 3):


											Assets		Liabilities
	Available-for-Sale Debt Securities						Equity securities		Short-term investments		Other investments		GLB (1)
Year Ended December 31, 2020	Non-U.S.		Corporate and asset-backed securities		MBS
(in millions of U.S. dollars)
Balance, beginning of year	$	449	$	1,451	$	60	$	69	$	6	$	10	$	897
Transfers into Level 3	—		134		—		—		—		—		—
Transfers out of Level 3	(16)		(73)		(1)		(3)		—		—		—
Change in Net Unrealized Gains/Losses in OCI	19		(8)		—		—		—		—		—
Net Realized Gains/Losses	(1)		(30)		—		1		(1)		—		202
Purchases	274		708		2		23		14		—		—
Sales	(122)		(186)		—		(17)		(2)		—		—
Settlements	(57)		(423)		(1)		—		(12)		—		—
Other	—		—		—		—		—		—		(10)
Balance, end of year	$	546	$	1,573	$	60	$	73	$	5	$	10	$	1,089
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—	$	(5)	$	—	$	4	$	—	$	—	$	202
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date	$	16	$	(6)	$	—	$	—	$	—	$	—	$	—

(1)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.


	Assets												Liabilities
	Available-for-Sale Debt Securities						Equity securities		Short-term investments		Other investments		GLB (1)
Year Ended December 31, 2019	Non-U.S.		Corporate and asset-backed securities		MBS
(in millions of U.S. dollars)
Balance, beginning of year	$	345	$	1,299	$	61	$	57	$	1	$	11	$	861
Transfers into Level 3	11		23		—		—		—		—		—
Transfers out of Level 3	(24)		(38)		(16)		—		—		—		—
Change in Net Unrealized Gains/Losses in OCI	13		(2)		—		1		—		—		—
Net Realized Gains/Losses	(1)		(4)		—		(2)		—		—		4
Purchases	228		577		19		34		6		—		—
Sales	(70)		(125)		(1)		(21)		—		—		—
Settlements	(53)		(279)		(3)		—		(1)		(1)		—
Other	—		—		—		—		—		—		32
Balance, end of year	$	449	$	1,451	$	60	$	69	$	6	$	10	$	897
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—	$	(2)	$	—	$	(3)	$	—	$	—	$	4
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date	$	7	$	(8)	$	—	$	—	$	—	$	—	$	—

(1)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.


	Assets												Liabilities
	Available-for-Sale Debt Securities								Short-term investments				Other derivative instruments		GLB (1)
Year Ended December 31, 2018	Non-U.S.		Corporate and asset-backed securities		MBS		Equity securities				Other investments
(in millions of U.S. dollars)
Balance, beginning of year	$	93	$	1,037	$	78	$	44	$	—	$	263	$	2	$	550
Transfers into Level 3	13		24		1		—		5		—		—		—
Transfers out of Level 3	(2)		(31)		(3)		—		—		(252)		—		—
Change in Net Unrealized Gains/Losses in OCI	(12)		(4)		—		(2)		—		(2)		—		—
Net Realized Gains/Losses	(3)		(5)		—		6		—		1		(2)		248
Purchases	334		672		5		37		9		50		—		—
Sales	(69)		(164)		—		(28)		—		—		—		—
Settlements	(9)		(230)		(20)		—		(13)		(49)		—		—
Other	—		—		—		—		—		—		—		63
Balance, end of year	$	345	$	1,299	$	61	$	57	$	1	$	11	$	—	$	861
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	(1)	$	(7)	$	—	$	(1)	$	—	$	1	$	—	$	248

(1)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

b) Financial instruments disclosed, but not measured, at fair value

Chubb uses various financial instruments in the normal course of its business. Our insurance contracts are excluded from fair value of financial instruments accounting guidance, and therefore, are not included in the amounts discussed below.

The carrying values of cash, other assets, other liabilities, and other financial instruments not included below approximated their fair values.

Investments in partially-owned insurance companies

Fair values for investments in partially-owned insurance companies are based on Chubb’s share of the net assets based on the financial statements provided by those companies and are excluded from the valuation hierarchy tables below.

Short- and long-term debt, repurchase agreements, and trust preferred securities

Where practical, fair values for short-term debt, long-term debt, repurchase agreements, and trust preferred securities are estimated using discounted cash flow calculations based principally on observable inputs including incremental borrowing rates, which reflect Chubb’s credit rating, for similar types of borrowings with maturities consistent with those remaining for the debt being valued.

The following tables present fair value, by valuation hierarchy, and carrying value of the financial instruments not measured at fair value:


December 31, 2020	Fair Value								Net Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities held to maturity
U.S. Treasury / Agency	$	1,395	$	57	$	—	$	1,452	$	1,392
Non-U.S.	—		1,405		—		1,405		1,288
Corporate and asset-backed securities	—		2,438		—		2,438		2,150
Mortgage-backed securities	—		2,146		—		2,146		1,999
Municipal	—		5,069		—		5,069		4,824
Total assets	$	1,395	$	11,115	$	—	$	12,510	$	11,653
Liabilities:
Repurchase agreements	$	—	$	1,405	$	—	$	1,405	$	1,405
Short-term debt	—		—		—		—		—
Long-term debt	—		17,487		—		17,487		14,948
Trust preferred securities	—		473		—		473		308
Total liabilities	$	—	$	19,365	$	—	$	19,365	$	16,661


December 31, 2019	Fair Value								Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities held to maturity
U.S. Treasury / Agency	$	1,292	$	55	$	—	$	1,347	$	1,318
Non-U.S.	—		1,485		—		1,485		1,423
Corporate and asset-backed securities	—		2,436		32		2,468		2,349
Mortgage-backed securities	—		2,396		—		2,396		2,331
Municipal	—		5,309		—		5,309		5,160
Total assets	$	1,292	$	11,681	$	32	$	13,005	$	12,581
Liabilities:
Repurchase agreements	$	—	$	1,416	$	—	$	1,416	$	1,416
Short-term debt	—		1,307		—		1,307		1,299
Long-term debt	—		15,048		—		15,048		13,559
Trust preferred securities	—		467		—		467		308
Total liabilities	$	—	$	18,238	$	—	$	18,238	$	16,582

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

Goodwill and Intangible Assets Disclosure [Abstract]

Reinsurance

12 Months Ended

Dec. 31, 2020

Reinsurance Disclosures [Abstract]

Reinsurance

a) Consolidated reinsurance

Chubb purchases reinsurance to manage various exposures including catastrophe risks. Although reinsurance agreements contractually obligate Chubb's reinsurers to reimburse it for the agreed-upon portion of its gross paid losses, they do not discharge Chubb's primary liability. The amounts for net premiums written and net premiums earned in the Consolidated statements of operations are net of reinsurance. The following table presents direct, assumed, and ceded premiums:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Premiums written
Direct	$	37,749	$	36,848	$	34,782
Assumed	3,512		3,276		3,186
Ceded	(7,441)		(7,849)		(7,389)
Net	$	33,820	$	32,275	$	30,579
Premiums earned
Direct	$	37,037	$	35,876	$	34,108
Assumed	3,323		3,107		3,175
Ceded	(7,243)		(7,693)		(7,219)
Net	$	33,117	$	31,290	$	30,064

Ceded losses and loss expenses incurred were $5.0 billion, $4.9 billion, and $5.6 billion for the years ended December 31, 2020, 2019, and 2018, respectively.

b) Reinsurance recoverable on ceded reinsurance


	December 31, 2020				December 31, 2019
(in millions of U.S. dollars)	Net Reinsurance Recoverable (1)		Valuation allowance		Net Reinsurance Recoverable (1)		Valuation allowance
Reinsurance recoverable on unpaid losses and loss expenses	$	14,647	$	257	$	14,181	$	240
Reinsurance recoverable on paid losses and loss expenses	945		57		1,000		76
Reinsurance recoverable on losses and loss expenses	$	15,592	$	314	$	15,181	$	316
Reinsurance recoverable on policy benefits	$	206	$	5	$	197	$	4

(1) Net of valuation allowance for uncollectible reinsurance.

The increase in reinsurance recoverable on losses and loss expenses in 2020 was primarily due to catastrophe losses, partially offset by crop activity and prior period development.

We evaluate the financial condition of our reinsurers and potential reinsurers on a regular basis and also monitor concentrations of credit risk with reinsurers. The valuation allowance for uncollectible reinsurance is required principally due to the potential failure of reinsurers to indemnify Chubb, primarily because of disputes under reinsurance contracts and insolvencies. We have established a valuation allowance for amounts estimated to be uncollectible on both unpaid and paid losses as well as future policy benefits. Refer to Note 1 d) for a discussion of the valuation allowance methodology.

The following table presents a roll-forward of valuation allowance for uncollectible reinsurance related to Reinsurance recoverable on loss and loss expenses:


(in millions of U.S. dollars)	Year Ended December 31, 2020
Valuation allowance for uncollectible reinsurance - beginning of period	$	316
Provision for uncollectible reinsurance	21
Write-offs charged against the valuation allowance	(25)
Foreign exchange revaluation	2
Valuation allowance for uncollectible reinsurance - end of period	$	314

The following tables present a listing, at December 31, 2020, of the categories of Chubb's reinsurers:


December 31, 2020	Gross Reinsurance Recoverable on Loss and Loss Expenses		Valuation allowance for Uncollectible Reinsurance		% of Gross Reinsurance Recoverable
(in millions of U.S. dollars, except for percentages)
Categories
Largest reinsurers	$	7,267	$	88	1.2	%
Other reinsurers rated A- or better	4,901		58		1.2	%
Other reinsurers rated lower than A- or not rated	466		64		13.7	%
Pools	366		14		3.8	%
Structured settlements	521		11		2.1	%
Captives	2,107		11		0.5	%
Other	278		68		24.5	%
Total	$	15,906	$	314	2.0	%


Largest Reinsurers
ABR Reinsurance Capital Holdings	HDI Group (Hannover Re)	Munich Re Group	Swiss Re Group
Berkshire Hathaway Insurance Group	Lloyd's of London	Partner Re Group


Categories of Chubb's reinsurers						Comprises:
Largest reinsurers						• All groups of reinsurers or captives where the gross recoverable exceeds one percent of Chubb's total shareholders' equity.
Other reinsurers rated A- or better						• All reinsurers rated A- or better that were not included in the largest reinsurer category.
Other reinsurers rated lower than A- or not rated						• All reinsurers rated lower than A- or not rated that were not included in the largest reinsurer category.
Pools						• Related to Chubb's voluntary pool participation and Chubb's mandatory pool participation required by law in certain states.
Structured settlements						• Annuities purchased from life insurance companies to settle claims. Since we retain ultimate liability in the event that the life company fails to pay, we reflect the amounts as both a liability and a recoverable/receivable for GAAP purposes.
Captives						• Companies established and owned by our insurance clients to assume a significant portion of their direct insurance risk from Chubb; structured to allow clients to self-insure a portion of their reinsurance risk. It generally is our policy to obtain collateral equal to expected losses. Where appropriate, exceptions are granted but only with review and approval at a senior officer level. Excludes captives included in the largest reinsurer category.
Other						• Amounts recoverable that are in dispute or are from companies that are in supervision, rehabilitation, or liquidation.

The valuation allowance for uncollectible reinsurance is principally based on an analysis of the credit quality of the reinsurer and collateral balances. We establish the valuation allowance for uncollectible reinsurance for the Other category based on a case-by-case analysis of individual situations including the merits of the underlying matter, credit and collateral analysis, and consideration.

Intangible Assets

12 Months Ended

Dec. 31, 2020

Intangible Assets Disclosure [Text Block]

Goodwill and Other intangible assets

Goodwill

The following table presents a roll-forward of Goodwill by segment:


(in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Chubb Consolidated
Balance at December 31, 2018	$	6,946	$	2,230	$	134	$	4,770	$	371	$	820	$	15,271
Foreign exchange revaluation and other	9		4		—		15		—		(3)		25
Balance at December 31, 2019	$	6,955	$	2,234	$	134	$	4,785	$	371	$	817	$	15,296
Acquisition of Banchile Seguros de Vida	—		—		—		16		—		28		44
Foreign exchange revaluation and other	17		6		—		35		—		2		60
Balance at December 31, 2020	$	6,972	$	2,240	$	134	$	4,836	$	371	$	847	$	15,400

Other intangible assets

Other intangible assets at December 31, 2020 and 2019 were $5,811 million and $6,063 million, respectively, principally acquired from the Chubb Corp acquisition. Other intangible assets in 2020 and 2019 comprised $2,846 million and $3,114 million, respectively, that are subject to amortization, principally agency distribution relationships and renewal rights, and $2,965 million and $2,949 million, respectively, that are not subject to amortization, principally trademarks. Amortization expense related to purchased intangibles was $290 million, $305 million, and $339 million for the years ended December 31, 2020, 2019, and 2018, principally related to agency distribution relationships and renewal rights.

The following table presents, as of December 31, 2020, the expected estimated pre-tax amortization expense (benefit) of purchased intangibles, at current foreign currency exchange rates, for the next five years:


	Associated with the Chubb Corp Acquisition
For the Years Ending December 31 (in millions of U.S. dollars)	Agency distribution relationships and renewal rights		Fair value adjustment on Unpaid losses and loss expense (1)		Total		Other intangible assets		Total Amortization of purchased intangibles
2021	$	217	$	(20)	$	197	$	89	$	286
2022	197		(14)		183		101		284
2023	178		(7)		171		96		267
2024	160		(6)		154		90		244
2025	145		(6)		139		89		228
Total	$	897	$	(53)	$	844	$	465	$	1,309

(1)In connection with the Chubb Corp acquisition, we recorded an increase to Unpaid losses and loss expenses acquired to adjust the carrying value of Chubb Corp's historical Unpaid losses and loss expenses to fair value as of the acquisition date. This fair value adjustment amortizes through Amortization of purchased intangibles on the Consolidated statements of operations through the year 2032. The balance of the fair value adjustment on Unpaid losses and loss expense was $110 million and $145 million at December 31, 2020 and 2019, respectively. Refer to Note 1(h) for additional information.

VOBA

The following table presents a roll-forward of VOBA:


(in millions of U.S. dollars)	2020		2019		2018
Balance, beginning of year	$	306	$	295	$	326
Amortization of VOBA (1)	(27)		(24)		(25)
Foreign exchange revaluation and other	(16)		35		(6)
Balance, end of year	$	263	$	306	$	295

(1)Recognized in Policy acquisition costs in the Consolidated statements of operations.

The following table presents, as of December 31, 2020, the expected estimated pre-tax amortization expense related to VOBA for the next five years at current foreign exchange rates:


For the Years Ending December 31	VOBA
(in millions of U.S. dollars)
2021	$	22
2022	21
2023	19
2024	17
2025	16
Total	$	95

Unpaid losses and loss expenses

12 Months Ended

Dec. 31, 2020

Liability for Claims and Claims Adjustment Expense [Abstract]

Unpaid Losses and Loss Expenses

Unpaid losses and loss expenses

Chubb establishes reserves for the estimated unpaid ultimate liability for losses and loss expenses under the terms of its policies and agreements. Reserves include estimates for both claims that have been reported and for IBNR claims, and include estimates of expenses associated with processing and settling these claims. Reserves are recorded in Unpaid losses and loss expenses in the consolidated balance sheets. While we believe that our reserves for unpaid losses and loss expenses at December 31, 2020 are adequate, new information or trends may lead to future developments in incurred loss and loss expenses significantly greater or less than the reserves provided. Any such revisions could result in future changes in estimates of losses or reinsurance recoverable and would be reflected in our results of operations in the period in which the estimates are changed.

The following table presents a reconciliation of beginning and ending Unpaid losses and loss expenses:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Gross unpaid losses and loss expenses, beginning of year	$	62,690	$	62,960	$	63,179
Reinsurance recoverable on unpaid losses (1)	(14,181)		(14,689)		(14,014)
Net unpaid losses and loss expenses, beginning of year	48,509		48,271		49,165


Net losses and loss expenses incurred in respect of losses occurring in:
Current year	22,124		19,575		19,048
Prior years (2)	(414)		(845)		(981)
Total	21,710		18,730		18,067
Net losses and loss expenses paid in respect of losses occurring in:
Current year	7,782		7,894		7,544
Prior years	9,652		10,579		10,796
Total	17,434		18,473		18,340
Foreign currency revaluation and other	379		(19)		(621)
Net unpaid losses and loss expenses, end of year	53,164		48,509		48,271
Reinsurance recoverable on unpaid losses (1)	14,647		14,181		14,689
Gross unpaid losses and loss expenses, end of year	$	67,811	$	62,690	$	62,960

(1) Net of valuation allowance for uncollectible reinsurance.

(2) Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments and earned premiums totaling $19 million, $53 million, and $85 million for 2020, 2019, and 2018, respectively.

The increase in gross and net unpaid losses and loss expense in 2020 was driven by catastrophe losses incurred, principally from the COVID-19 pandemic. The increase in net unpaid losses and loss expense in 2019 reflected an increase in underlying reserves, offset by favorable prior period development and payments related to catastrophic events.

The loss development tables under section c) below, present Chubb’s historical incurred and paid claims development by broad product line through December 31, 2020, net of reinsurance, as well as the cumulative number of reported claims, IBNR balances, and other supplementary information.

The following table presents a reconciliation of the loss development tables to the liability for unpaid losses and loss expenses in the consolidated balance sheet:


Reconciliation of Reserve Balances to Liability for Unpaid Loss and Loss Expenses
(in millions of U.S. dollars)	December 31, 2020
Presented in the loss development tables:
North America Commercial P&C Insurance — Workers' Compensation	$	9,600
North America Commercial P&C Insurance — Liability	17,441
North America Commercial P&C Insurance — Other Casualty	2,124
North America Commercial P&C Insurance — Non-Casualty	2,491
North America Personal P&C Insurance	3,025
Overseas General Insurance — Casualty	6,832
Overseas General Insurance — Non-Casualty	2,725
Global Reinsurance — Casualty	1,200
Global Reinsurance — Non-Casualty	312
Excluded from the loss development tables:
Other	4,742
Net unpaid loss and allocated loss adjustment expense	50,492
Ceded unpaid loss and allocated loss adjustment expense:
North America Commercial P&C Insurance — Workers' Compensation	$	1,461
North America Commercial P&C Insurance — Liability	5,743
North America Commercial P&C Insurance — Other Casualty	564
North America Commercial P&C Insurance — Non-Casualty	1,380
North America Personal P&C Insurance	141
Overseas General Insurance — Casualty	2,426
Overseas General Insurance — Non-Casualty	1,686
Global Reinsurance — Casualty	29
Global Reinsurance — Non-Casualty	104
Other	1,153
Ceded unpaid loss and allocated loss adjustment expense	14,687
Unpaid loss and loss expense on other than short-duration contracts (1)	1,109
Unpaid unallocated loss adjustment expenses	1,523
Unpaid losses and loss expenses	$	67,811

(1) Primarily includes the claims reserve of our International A&H business and Life Insurance segment reserves.

Business excluded from the loss development tables

“Other” shown in the reconciliation table comprises businesses excluded from the loss development tables:

•North America Agricultural Insurance segment business, which is short-tailed with the majority of the liabilities expected to be resolved in the ensuing twelve months;

•Corporate, which includes run-off liabilities such as asbestos and environmental and other mass tort exposures and which impact accident years older than those shown in the loss development tables below;

•Life Insurance segment business, which is generally written using long-duration contracts; and

•Certain subsets of our business due to data limitations or unsuitability to the loss development table presentation, including:

◦We underwrite loss portfolio transfers at various times; by convention, all premium and losses associated with these transactions are recorded to the policy period of the transaction, even though the accident dates of the claims covered may be a decade or more in the past. We also underwrite certain high attachment, high limit, multiple-line and excess of aggregate coverages for large commercial clients. Changes in incurred loss and cash flow patterns are volatile and sufficiently different from those of typical insureds. This category includes the loss portfolio transfer of Fireman’s Fund personal lines run-off liabilities and Alternative Risk Solutions business within the North America Commercial P&C Insurance segment;

◦2015 and prior paid history on a subset of previously acquired international businesses, within the Overseas General Insurance segment, due to limitations on the data prior to the acquisition;

◦Reinsurance recoverable bad debt; and

◦Purchase accounting adjustments related to unpaid losses and loss expenses for Chubb Corp.

a) Description of Reserving Methodologies

Our recorded reserves represent management's best estimate of the provision for unpaid claims as of the balance sheet date. The process of establishing loss and loss expense reserves can be complex and is subject to considerable uncertainty as it requires the use of estimates and judgments based on circumstances underlying the insured loss at the date of accrual. The reserves for our various product lines each require different qualitative and quantitative assumptions and judgments to be made. Management's best estimate is developed after collaboration with actuarial, underwriting, claims, legal, and finance departments and culminates with the input of reserve committees. Each business unit reserve committee includes the participation of the relevant parties from actuarial, finance, claims, and unit senior management and has the responsibility for finalizing, recommending and approving the estimate to be used as management's best estimate. Reserves are further reviewed by Chubb's Chief Actuary and senior management. The objective of such a process is to determine a single estimate that we believe represents a better estimate than any other and which is viewed by management to be the best estimate of ultimate loss settlements.

This estimate is based on a combination of exposure and experience-based actuarial methods (described below) and other considerations such as claims reviews, reinsurance recovery assumptions and/or input from other knowledgeable parties such as underwriting. Exposure-based methods are most commonly used on relatively immature origin years (i.e., the year in which the losses were incurred — “accident year” or “report year”), while experience-based methods provide a view based on the projection of loss experience that has emerged as of the valuation date. Greater reliance is placed upon experience-based methods as the pool of emerging loss experience grows and where it is deemed sufficiently credible and reliable as the basis for the estimate. In comparing the held reserve for any given origin year to the actuarial projections, judgment is required as to the credibility, uncertainty and inherent limitations of applying actuarial techniques to historical data to project future loss experience. Examples of factors that impact such judgments include, but are not limited to, the following:

•nature and complexity of underlying coverage provided and net limits of exposure provided;

•segmentation of data to provide sufficient homogeneity and credibility for loss projection methods;

•extent of credible internal historical loss data and reliance upon industry information as required;

•historical variability of actual loss emergence compared with expected loss emergence;

•reported and projected loss trends;

•extent of emerged loss experience relative to the remaining expected period of loss emergence;

•rate monitor information for new and renewal business;

•changes in claims handling practice;

•inflation;

•the legal environment;

•facts and circumstances of large claims;

•terms and conditions of the contracts sold to our insured parties;

•impact of applicable reinsurance recoveries; and

•nature and extent of underlying assumptions.

We have actuarial staff within each of our business units who analyze loss reserves (including loss expenses) and regularly project estimates of ultimate losses and the corresponding indications of the required IBNR reserve. Our reserving approach is a comprehensive ground-up process using data at a detailed level that reflects the specific types and coverages of the diverse products written by our various operations. The data presented in this disclosure was prepared on a more aggregated basis and with a focus on changes in incurred loss estimates over time as well as associated cash flows. We note that data prepared on this basis may not demonstrate the full spectrum of characteristics that are evident in the more detailed level studied internally.

We perform an actuarial reserve review for each product line at least once a year. For most product lines, one or more standard actuarial reserving methods may be used to determine estimates of ultimate losses and loss expenses, and from these estimates, a single actuarial central estimate is selected. The actuarial central estimate is an input to the reserve committee process described above. For the few product lines that do not lend themselves to standard actuarial reserving methods, appropriate techniques are applied to produce the actuarial central estimates. For example, run-off asbestos and environmental liability estimates are better suited to the application of account-specific exposure-based analyses to best evaluate their associated aggregate reserve levels.

b) Standard actuarial reserving methods

The judgments involved in projecting the ultimate losses include the use and interpretation of various standard actuarial reserving methods that place reliance on the extrapolation of actual historical data, loss development patterns, industry data, and other benchmarks as appropriate.

Standard actuarial reserving methods include, but are not limited to, expected loss ratio, paid and reported loss development, and Bornhuetter-Ferguson methods. A general description of these methods is provided below. In addition to these standard methods, depending upon the product line characteristics and available data, we may use other recognized actuarial methods and approaches. Implicit in the standard actuarial methods that we generally utilize is the need for two fundamental assumptions: first, the pattern by which losses are expected to emerge over time for each origin year, and second the expected loss ratio for each origin year.

The expected loss ratio for any particular origin year is selected after consideration of a number of factors, including historical loss ratios adjusted for rate changes, premium and loss trends, industry benchmarks, the results of policy level loss modeling at the time of underwriting, and/or other more subjective considerations for the product line (e.g., terms and conditions) and external environment as noted above. The expected loss ratio for a given origin year is initially established at the start of the origin year as part of the planning process. This analysis is performed in conjunction with underwriters and management. The expected loss ratio method arrives at an ultimate loss estimate by multiplying the expected ultimate loss ratio by the corresponding premium base. This method is most commonly used as the basis for the actuarial central estimate for immature origin periods on product lines where the actual paid or reported loss experience is not yet deemed sufficiently credible to serve as the principal basis for the selection of ultimate losses. The expected loss ratio for a given origin year may be modified over time if the underlying assumptions differ from the original assumptions (e.g., the assessment of prior year loss ratios, loss trend, rate changes, actual claims, or other information).

Our selected paid and reported development patterns provide a benchmark against which the actual emerging loss experience can be monitored. Where possible, development patterns are selected based on historical loss emergence by origin year. For product lines where the historical data is viewed to have low statistical credibility, the selected development patterns also reflect relevant industry benchmarks and/or experience from similar product lines written elsewhere within Chubb. This most commonly occurs for relatively new product lines that have limited historical data or for high severity/low frequency portfolios where our historical experience exhibits considerable volatility and/or lacks credibility. The paid and reported loss development methods convert the selected loss emergence pattern to a set of multiplicative factors which are then applied to actual paid or reported losses to arrive at an estimate of ultimate losses for each period. Due to their multiplicative nature, the paid and reported loss development methods will leverage differences between actual and expected loss emergence. These methods tend to be utilized for more mature origin periods and for those portfolios where the loss emergence has been relatively consistent over time.

The Bornhuetter-Ferguson method is a combination of the expected loss ratio method and the loss development method, where the loss development method is given more weight as the origin year matures. This approach allows a logical transition between the expected loss ratio method which is generally utilized at earlier maturities and the loss development methods which are typically utilized at later maturities. We usually apply this method using reported loss data although paid data may also be used.

Short-tail business

Short-tail business generally describes product lines for which losses are typically known and paid shortly after the loss occurs. This would include, for example, most property, personal accident, and automobile physical damage policies that we write. Due to the short reporting and development pattern for these product lines, the uncertainty associated with our estimate of ultimate losses for any particular accident period diminishes relatively quickly as actual loss experience emerges. We typically assign credibility to methods that incorporate actual loss emergence, such as the paid and reported loss development and Bornhuetter-Ferguson methods, sooner than would be the case for long-tail lines at a similar stage of development for a given origin year. The reserving process for short-tail losses arising from catastrophic events typically involves an assessment by the claims department, in conjunction with underwriters and actuaries, of our exposure and estimated losses immediately following an event and then subsequent revisions of the estimated losses as our insureds provide updated actual loss information.

Long-tail business

Long-tail business describes lines of business for which specific losses may not be known/reported for some period and for which claims can take significant time to settle/close. This includes most casualty lines such as general liability, D&O, and workers' compensation. There are various factors contributing to the uncertainty and volatility of long-tail business. Among these are:

•The nature and complexity of underlying coverage provided and net limits of exposure provided;

•Our historical loss data and experience is sometimes too immature and lacking in credibility to rely upon for reserving purposes. Where this is the case, in our reserve analysis we may utilize industry loss ratios or industry benchmark development patterns that we believe reflect the nature and coverage of the underwritten business and its future development, where available. For such product lines, actual loss experience may differ from industry loss statistics as well as loss experience for previous underwriting years;

•The difficulty in estimating loss trends, claims inflation (e.g., medical and judicial) and underlying economic conditions;

•The need for professional judgment to estimate loss development patterns beyond that represented by historical data using supplemental internal or industry data, extrapolation, or a blend of both;

•The need to address shifts in business mix or volume over time when applying historical paid and reported loss development patterns from older origin years to more recent origin years. For example, changes over time in the processes and procedures for establishing case reserves can distort reported loss development patterns or changes in ceded reinsurance structures by origin year can alter the development of paid and reported losses;

•Loss reserve analyses typically require loss or other data be grouped by common characteristics in some manner. If data from two combined lines of business exhibit different characteristics, such as loss payment patterns, the credibility of the reserve estimate could be affected. Additionally, since casualty lines of business can have significant intricacies in the terms and conditions afforded to the insured, there is an inherent risk as to the homogeneity of the underlying data used in performing reserve analyses; and

•The applicability of the price change data used to estimate ultimate loss ratios for most recent origin years.

As described above, various factors are considered when determining appropriate data, assumptions, and methods used to establish the loss reserve estimates for long-tail product lines. These factors may also vary by origin year for given product lines. The derivation of loss development patterns from data and the selection of a tail factor to project ultimate losses from actual loss emergence require considerable judgment, particularly with respect to the extent to which historical loss experience is relied upon to support changes in key reserving assumptions.

c) Loss Development Tables

The tables were designed to present business with similar risk characteristics which exhibit like development patterns and generally similar trends, in order to provide insight into the nature, amount, timing and uncertainty of cash flows related to our claims liabilities.

Each table follows a similar format and reflects the following:

•The incurred loss triangle includes both reported case reserves and IBNR liabilities.

•Both the incurred and paid loss triangles include allocated loss adjustment expense (i.e., defense and investigative costs particular to individual claims) but exclude unallocated loss adjustment expense (i.e., the costs associated with internal claims staff and third-party administrators).

•The amounts in both triangles for the years ended December 31, 2011 to December 31, 2019 and average historical claim duration as of December 31, 2020, are presented as supplementary information.

•All data presented in the triangles is net of reinsurance recoverables.

•The IBNR reserves shown to the right of each incurred loss development exhibit reflect the net IBNR recorded as of December 31, 2020.

•The tables are presented retrospectively with respect to acquisitions where these are material and doing so is practicable. Most notably, the Chubb Corp acquisition is presented retrospectively. The unaudited consolidated data is presented solely for informational purposes and is not necessarily indicative of the consolidated data that might have been observed had the transactions been completed prior to the date indicated.

Historical dollar amounts are presented in this footnote on a constant-dollar basis, which is achieved by assuming constant foreign exchange rates for all periods in the loss triangles, translating prior period amounts using the same local currency exchange rates as the current year end. The impact of this conversion is to show the change between periods exclusive of the effect of fluctuations in exchange rates, which would otherwise distort the change in incurred loss and cash flow patterns shown. The change in incurred loss shown will differ from other GAAP disclosures of incurred prior period reserve development amounts, which include the effect of fluctuations in exchanges rates.

We provided guidance above on key assumptions that should be considered when reviewing this disclosure and information relating to how loss reserve estimates are developed. We believe the information provided in the “Loss Development Tables” section of the disclosure is of limited use for independent analysis or application of standard actuarial estimations.

Cumulative Number of Reported Claims

Reported claim counts, on a cumulative basis, are provided to the far right of each incurred loss development table. In our North America segments, we generally consider a reported claim to be one claim per coverage per claimant. For our North America segments, we refined our claim count methodology in 2020 for our U.S. operations. For workers' compensation, we moved from including losses below the deductible in our reported claims to excluding them. This reduction in reported claims aligns claim counts to the portion of the claims to which Chubb has incurred losses, which we view as a more meaningful presentation. For non-casualty, personal and liability, we aligned our claim count methodology to reflect a reported claim per claimant, per coverage basis, and including all reported claims with either an indemnity or expense transaction. These changes resulted in fewer reported claims in non-casualty and additional reported claims in personal and liability. In our Overseas General Insurance segment, we generally consider a reported claim to be on a per occurrence basis. Global Reinsurance segment’s portfolio comprises a mix of proportional and non-proportional treaties. The proportional treaties are reported on a bulk basis and do not lend themselves to meaningful claim count data. As such, we do not provide claim count information for our Global Reinsurance segment.

We exclude claims closed without payment. Claims are counted on a direct basis without consideration of ceded reinsurance. Use of the presented claim counts in analysis of company experience has significant limitations, including:

•Claims for certain events and/or product lines, such as portions of our A&H business, are not reported on an individual basis, but rather in bulk and thus not available for inclusion in this disclosure.

•Each segment typically has a mixture of primary and excess experience which has shifted over time.

•Captive business, especially in Workers' Compensation and Liability, largely represents fronted business where our net exposure to loss is minimal; however, since the claim count is based on direct claims, there is a mismatch between direct claims and net loss dollars, the extent of which varies by accident year.

Reported claim counts include open claims which have case reserves but exclude claims that have been incurred but not reported. As such the reported claims are not consistent with the incurred losses in the triangle, which include incurred but not reported losses. One can calculate reported losses by subtracting incurred but not reported losses from incurred losses in the triangle. Reported claim counts are also inconsistent with losses in the paid loss triangle, since reported counts would include claims with case reserves but no payments to date.

North America Commercial P&C Insurance — Workers' Compensation — Long-tail

This product line has a substantial geographic spread and a broad mix across industries. Types of coverage include risk management business predominantly with high deductible policies, loss sensitive business (i.e., retrospectively-rated policies), business fronted for captives, as well as excess and primary guaranteed cost coverages.

The triangle below shows all loss and allocated expense development for the workers' compensation product line. In our prior period development disclosure, we exclude any loss development where there is a directly related premium adjustment. For workers' compensation, changes in the exposure base due to payroll audits will drive changes in ultimate losses. In addition, we record involuntary pool assumptions (premiums and losses) on a lagged basis. Both of these items will influence the development in the triangle, particularly the first prior accident year, and are included in the reconciliation table presented on page F-58.


North America Commercial P&C Insurance — Workers' Compensation — Long-tail (continued)
Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,037	$	1,030		$	1,046	$	1,049	$	1,053	$	1,022	$	1,012	$	1,009	$	988	$	973	$	208	45
2012			1,050			1,011		1,030		1,040		1,011		989		986		977		953		234		44
2013						1,109		1,108		1,122		1,127		1,086		1,073		1,037		1,014		280		43
2014								1,207		1,201		1,217		1,215		1,163		1,100		1,073		347		45
2015										1,282		1,259		1,276		1,279		1,217		1,154		419		50
2016												1,367		1,361		1,383		1,378		1,269		530		51
2017														1,413		1,380		1,399		1,393		723		50
2018																1,359		1,361		1,379		709		51
2019																		1,391		1,384		767		47
2020																				1,367		1,086		24
Total																				$	11,959


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	119	$	294		$	411	$	484	$	533	$	567	$	595	$	616	$	640	$	654
2012			111			271		365		436		486		532		574		592		612
2013						107		286		422		506		553		587		616		633
2014								113		295		410		484		532		566		599
2015										116		301		418		501		564		606
2016												122		326		452		529		584
2017														120		313		437		516
2018																130		329		451
2019																		143		341
2020																				111
Total																				$	5,107


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	2,748
Accident years 2011 - 2020 from tables above	6,852
All Accident years	$	9,600


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(94)
Accident years 2011 - 2020 from tables above	(256)
All Accident years	$	(350)



Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	10	%	16	%	10	%	7	%	5	%	4	%	3	%	2	%	2	%	1	%

North America Commercial P&C Insurance — Liability — Long-tail

This line consists of primary and excess liability exposures, including medical liability and professional lines, including directors and officers (D&O) liability, errors and omissions (E&O) liability, employment practices liability (EPL), fidelity bonds, and fiduciary liability.

The primary and excess liability business represents the largest part of these exposures. The former includes both monoline and commercial package liability. The latter includes a substantial proportion of commercial umbrella, excess and high excess business, where loss activity can produce significant volatility in the loss triangles at later ages within an accident year (and sometimes across years) due to the size of the limits afforded and the complex nature of the underlying losses.

This line includes management and professional liability products provided to a wide variety of clients, from national accounts to small firms along with private and not-for-profit organizations, distributed through brokers, agents, wholesalers and MGAs. Many of these coverages, particularly D&O and E&O, are typically written on a claims-made form. While most of the coverages are underwritten on a primary basis, there are significant amounts of excess exposure with large policy limits.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	3,500	$	3,586		$	3,630	$	3,665	$	3,593	$	3,498	$	3,384	$	3,316	$	3,193	$	3,143	$	226	25
2012			3,552			3,628		3,613		3,565		3,524		3,426		3,331		3,235		3,235		353		25
2013						3,547		3,542		3,543		3,533		3,430		3,216		3,122		2,964		317		25
2014								3,535		3,586		3,674		3,717		3,656		3,470		3,346		572		25
2015										3,560		3,709		3,819		3,976		3,943		3,736		855		27
2016												3,534		3,595		3,692		3,805		3,799		962		27
2017														3,322		3,499		3,581		3,631		1,475		27
2018																3,375		3,494		3,696		1,737		28
2019																		3,452		3,628		2,381		28
2020																				4,098		3,695		24
Total																				$	35,276



Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	160	$	652		$	1,209	$	1,805	$	2,214	$	2,477	$	2,659	$	2,741	$	2,827	$	2,863
2012			166			656		1,172		1,680		2,092		2,326		2,502		2,619		2,688
2013						130		548		1,192		1,597		2,007		2,232		2,374		2,465
2014								164		679		1,250		1,804		2,202		2,442		2,584
2015										138		605		1,206		1,856		2,291		2,533
2016												171		663		1,336		1,975		2,334
2017														161		617		1,162		1,701
2018																190		754		1,303
2019																		176		671
2020																				152
Total																				$	19,294


North America Commercial P&C Insurance — Liability — Long-tail (continued)
Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	1,459
Accident years 2011 - 2020 from tables above	15,982
All Accident years	$	17,441


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(176)
Accident years 2011 - 2020 from tables above	(117)
All Accident years	$	(293)


Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	5	%	14	%	17	%	16	%	12	%	7	%	5	%	3	%	2	%	1	%

North America Commercial P&C Insurance — Other Casualty — Long-tail

This product line consists of the remaining commercial casualty coverages such as automobile liability and aviation. There is also a small portion of commercial multi-peril (CMP) business in accident years 2014 and prior. The paid and reported data are impacted by some catastrophe loss activity primarily on the CMP exposures just noted.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	581	$	590		$	581	$	549	$	533	$	525	$	517	$	511	$	513	$	503	$	13	16
2012			634			606		577		561		520		519		509		507		505		2		16
2013						527		531		523		516		469		462		462		458		21		18
2014								595		583		581		597		555		539		539		25		17
2015										487		470		502		515		458		455		35		15
2016												504		502		527		524		481		61		16
2017														532		566		577		616		118		17
2018																536		564		575		198		17
2019																		606		637		284		16
2020																				646		517		9
Total																				$	5,415


North America Commercial P&C Insurance — Other-Casualty — Long-tail (continued)
Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	86	$	235		$	341	$	400	$	437	$	461	$	466	$	480	$	486	$	486
2012			69			223		320		387		435		470		487		493		502
2013						69		197		271		348		385		411		419		426
2014								80		220		318		391		455		474		501
2015										47		137		215		305		371		395
2016												52		146		246		323		374
2017														66		175		313		381
2018																74		169		270
2019																		70		190
2020																				53
Total																				$	3,578


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	287
Accident years 2011 - 2020 from tables above	1,837
All Accident years	$	2,124


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	23
Accident years 2011 - 2020 from tables above	19
All Accident years	$	42



Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	12	%	23	%	19	%	14	%	10	%	5	%	3	%	2	%	1	%	—	%

North America Commercial P&C Insurance — Non-Casualty — Short-tail

This product line represents first party commercial product lines that are short-tailed in nature, such as property, inland marine, ocean marine, surety and A&H. There is a wide diversity of products, primary and excess coverages, and policy sizes. During this ten-year period, this product line was also impacted by natural catastrophes mainly in the 2012, 2017, and 2018 accident years.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,960	$	1,934		$	1,877	$	1,856	$	1,835	$	1,840	$	1,835	$	1,835	$	1,835	$	1,833	$	4	416
2012			2,033			1,916		1,883		1,864		1,859		1,847		1,844		1,850		1,844		(8)		426
2013						1,434		1,424		1,337		1,360		1,340		1,340		1,338		1,344		7		455
2014								1,643		1,661		1,579		1,559		1,549		1,550		1,558		10		483
2015										1,736		1,745		1,650		1,638		1,605		1,589		(1)		545
2016												1,911		1,890		1,799		1,782		1,818		32		650
2017														2,704		2,608		2,505		2,522		51		763
2018																2,053		2,240		2,175		71		901
2019																		2,052		2,037		166		1,036
2020																				3,150		1,061		927
Total																				$	19,870


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	939	$	1,574		$	1,718	$	1,777	$	1,787	$	1,811	$	1,816	$	1,821	$	1,825	$	1,830
2012			715			1,577		1,698		1,767		1,795		1,822		1,816		1,842		1,844
2013						651		1,138		1,238		1,285		1,311		1,324		1,333		1,335
2014								820		1,374		1,484		1,506		1,532		1,546		1,554
2015										727		1,343		1,488		1,556		1,572		1,574
2016												846		1,504		1,656		1,733		1,761
2017														979		2,087		2,303		2,394
2018																1,027		1,825		2,018
2019																		1,030		1,677
2020																				1,396
Total																				$	17,383


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	4
Accident years 2011 - 2020 from tables above	2,487
All Accident years	$	2,491


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	2
Accident years 2011 - 2020 from tables above	(37)
All Accident years	$	(35)


North America Commercial P&C Insurance — Non-Casualty — Short-tail (continued)
Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	46	%	38	%	8	%	3	%	1	%	1	%	—	%	1	%	—	%	—	%

North America Personal P&C Insurance — Short-tail

Chubb provides personal lines coverages for high-net-worth individuals and families in North America including homeowners, automobile, valuable articles (including fine art), umbrella liability, and recreational marine insurance offered through independent regional agents and brokers. A portfolio acquired from Fireman’s Fund is presented on a prospective basis beginning in May of accident year 2015. Reserves associated with prior accident periods were acquired through a loss portfolio transfer, which does not allow for a retrospective presentation. During this ten-year period, this segment was also impacted by natural catastrophes, mainly in 2012, 2017 and 2018 accident years.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	2,208	$	2,210		$	2,185	$	2,173	$	2,164	$	2,161	$	2,160	$	2,158	$	2,159	$	2,157	$	7	179
2012			2,185			2,183		2,183		2,191		2,186		2,186		2,189		2,194		2,190		18		188
2013						1,860		1,888		1,897		1,900		1,924		1,937		1,945		1,948		26		132
2014								2,205		2,206		2,192		2,146		2,160		2,147		2,141		14		144
2015										2,494		2,550		2,561		2,544		2,563		2,570		21		148
2016												2,440		2,535		2,545		2,482		2,471		45		154
2017														3,035		3,069		3,002		2,998		96		163
2018																3,010		3,037		3,103		244		169
2019																		2,957		2,993		329		155
2020																				2,931		1,119		100
Total																				$	25,502


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,360	$	1,835		$	1,972	$	2,052	$	2,105	$	2,129	$	2,139	$	2,146	$	2,148	$	2,149
2012			1,177			1,806		1,957		2,063		2,117		2,149		2,164		2,163		2,165
2013						1,043		1,504		1,688		1,787		1,843		1,885		1,895		1,917
2014								1,310		1,765		1,926		2,035		2,080		2,106		2,116
2015										1,499		2,084		2,271		2,392		2,478		2,508
2016												1,453		2,052		2,211		2,314		2,370
2017														1,698		2,520		2,668		2,799
2018																1,926		2,549		2,706
2019																		1,668		2,437
2020																				1,334
Total																				$	22,501


North America Personal P&C Insurance — Short-tail (continued)
Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	24
Accident years 2011 - 2020 from tables above	3,001
All Accident years	$	3,025


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(1)
Accident years 2011 - 2020 from tables above	85
All Accident years	$	84


Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	57	%	24	%	7	%	5	%	3	%	1	%	1	%	—	%	—	%	—	%

Overseas General Insurance — Casualty — Long-tail

This product line is comprised of D&O liability, E&O liability, financial institutions (including crime/fidelity coverages), and non-U.S. general liability as well as aviation and political risk. Exposures are located around the world, including Europe, Latin America, and Asia. Approximately 45 percent of Chubb Overseas General business is generated by European accounts, exclusive of Lloyd's market. There is some U.S. exposure in Casualty from multinational accounts and in financial lines for Lloyd's market. The financial lines coverages are typically written on a claims-made form, while general liability coverages are typically on an occurrence basis and comprised of a mix of primary and excess businesses.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,255	$	1,262		$	1,254	$	1,244	$	1,158	$	1,090	$	1,079	$	1,027	$	1,023	$	1,025	$	31	37
2012			1,290			1,261		1,326		1,346		1,343		1,337		1,315		1,304		1,272		87		38
2013						1,281		1,279		1,276		1,322		1,276		1,242		1,182		1,148		86		39
2014								1,279		1,352		1,362		1,378		1,293		1,206		1,165		151		39
2015										1,196		1,296		1,328		1,351		1,326		1,265		199		41
2016												1,232		1,337		1,407		1,437		1,425		341		43
2017														1,227		1,332		1,381		1,433		384		43
2018																1,330		1,383		1,447		671		43
2019																		1,409		1,480		809		40
2020																				1,810		1,493		28
Total																				$	13,470


Overseas General Insurance — Casualty — Long-tail (continued)
Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	86	$	243		$	393	$	528	$	631	$	713	$	789	$	842	$	876	$	901
2012			75			252		441		597		713		857		929		973		1,040
2013						85		267		428		579		725		829		899		952
2014								111		293		473		608		725		811		876
2015										86		287		497		679		802		884
2016												127		324		534		687		815
2017														98		323		535		702
2018																112		334		503
2019																		126		341
2020																				110
Total																				$	7,124


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	486
Accident years 2011 - 2020 from tables above	6,346
All Accident years	$	6,832


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(59)
Accident years 2011 - 2020 from tables above	9
All Accident years	$	(50)



Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	8	%	15	%	15	%	12	%	10	%	8	%	6	%	4	%	4	%	3	%

Overseas General Insurance — Non-Casualty — Short-tail

This product line is comprised of commercial fire, marine (predominantly cargo), surety, personal automobile (in Latin America, Asia Pacific and Japan), personal cell phones, personal residential (including high net worth), energy and construction. In general, these lines have relatively stable payment and reporting patterns although they are impacted by natural catastrophes mainly in the 2011, 2017, and 2018 accident years. Latin America and Europe each make up about 30 percent of the Chubb Overseas General non-casualty book.


Overseas General Insurance — Non-Casualty — Short-tail (continued)
Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,908	$	1,995		$	1,938	$	1,898	$	1,879	$	1,867	$	1,859	$	1,849	$	1,844	$	1,843	$	6	543
2012			1,712			1,702		1,661		1,605		1,599		1,590		1,575		1,570		1,562		13		555
2013						1,787		1,780		1,714		1,665		1,660		1,633		1,620		1,610		19		573
2014								1,863		1,932		1,875		1,864		1,828		1,817		1,810		7		548
2015										1,963		2,083		2,062		2,030		2,011		2,003		24		571
2016												2,070		2,071		2,058		2,036		2,040		22		581
2017														2,222		2,264		2,245		2,225		18		589
2018																2,186		2,276		2,237		48		624
2019																		2,208		2,228		94		640
2020																				2,571		804		518
Total																				$	20,129


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	765	$	1,486		$	1,694	$	1,750	$	1,780	$	1,795	$	1,804	$	1,808	$	1,807	$	1,806
2012			679			1,237		1,425		1,485		1,508		1,518		1,530		1,532		1,532
2013						696		1,284		1,480		1,512		1,549		1,567		1,575		1,578
2014								758		1,438		1,651		1,715		1,746		1,759		1,774
2015										857		1,560		1,793		1,875		1,897		1,927
2016												1,013		1,679		1,881		1,954		1,981
2017														1,051		1,848		2,029		2,106
2018																1,006		1,753		1,962
2019																		1,050		1,747
2020																				1,085
Total																				$	17,498


(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	94
Accident years 2011 - 2020 from tables above	2,631
All Accident years	$	2,725


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(8)
Accident years 2011 - 2020 from tables above	(69)
All Accident years	$	(77)


Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	45	%	35	%	11	%	3	%	2	%	1	%	1	%	—	%	—	%	—	%

Global Reinsurance

Chubb analyzes its Global Reinsurance business on a treaty year basis rather than on an accident year basis. Treaty year data was converted to an accident year basis for the purposes of this disclosure. Mix shifts are an important consideration in these product line groupings. As proportional business and excess of loss business have different earning and loss reporting and payment patterns, this change in mix will affect the cash flow patterns across the accident years. In addition, the shift from excess to proportional business over time will make the cash flow patterns of older and more recent years difficult to compare. In general, the proportional business will pay out more quickly than the excess of loss business, as such, using older years development patterns may overstate the ultimate loss estimates in more recent years.

Global Reinsurance — Casualty — Long-tail

This product line includes proportional and excess coverages in general, automobile liability, professional liability, medical malpractice and workers' compensation, with exposures located around the world. In general, reinsurance exhibits less stable development patterns than primary business. In particular, general casualty reinsurance and excess coverages are long-tailed and can be very volatile.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	408	$	415		$	430	$	433	$	428	$	418	$	415	$	409	$	402	$	389	$	15
2012			387			384		392		395		379		373		372		374		379		11
2013						321		327		330		331		332		324		317		311		13
2014								334		335		340		343		345		348		331		16
2015										285		290		300		301		309		306		22
2016												224		228		236		236		245		27
2017														215		217		221		218		28
2018																246		249		256		48
2019																		239		248		90
2020																				247		153
Total																				$	2,930


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	70	$	146		$	195	$	236	$	267	$	292	$	312	$	325	$	332	$	338
2012			78			168		223		262		293		309		324		336		342
2013						65		143		186		222		242		260		269		272
2014								92		185		218		249		265		277		287
2015										90		159		192		217		233		250
2016												58		113		143		159		175
2017														47		100		122		140
2018																42		96		126
2019																		40		90
2020																				41
Total																				$	2,061


Global Reinsurance — Casualty — Long-tail (continued)
Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	331
Accident years 2011 - 2020 from tables above	869
All Accident years	$	1,200


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(10)
Accident years 2011 - 2020 from tables above	(12)
All Accident years	$	(22)


Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	21	%	23	%	12	%	10	%	7	%	5	%	4	%	3	%	2	%	2	%

Global Reinsurance — Non-Casualty — Short-tail

This product line includes property, property catastrophe, marine, credit/surety, A&H and energy. This product line is impacted by natural catastrophes, particularly in the 2011, 2017 and 2018 accident years. Of the non-catastrophe book, the mixture of business varies by year with approximately 77 percent of loss on proportional treaties in treaty year 2011 and after. This percentage has increased over time with the proportion being approximately 59 percent for treaty years 2011 to 2012 growing to an average of 82 percent for treaty years 2013 to 2020, with the remainder being written on an excess of loss basis.


Global Reinsurance — Non-Casualty — Short-tail (continued)
Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	277	$	279		$	276	$	266	$	267	$	268	$	267	$	268	$	267	$	269	$	1
2012			233			211		202		192		191		188		186		186		184		1
2013						162		160		148		143		144		141		141		140		—
2014								167		182		183		186		184		183		182		3
2015										147		155		162		162		155		161		4
2016												184		189		192		194		190		5
2017														397		424		454		451		10
2018																288		300		303		(8)
2019																		143		141		29
2020																				212		110
Total																				$	2,233


Global Reinsurance — Non-Casualty — Short-tail (continued)
Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	87	$	179		$	210	$	236	$	254	$	259	$	262	$	263	$	264	$	265
2012			45			130		157		167		173		178		180		181		180
2013						46		103		121		131		134		137		137		139
2014								66		131		154		165		171		173		175
2015										56		104		133		143		147		153
2016												57		133		161		172		178
2017														191		322		402		415
2018																94		258		277
2019																		35		86
2020																				63
Total																				$	1,931


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	10
Accident years 2011 - 2020 from tables above	302
All Accident years	$	312


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	—
Accident years 2011 - 2020 from tables above	(2)
All Accident years	$	(2)



Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	33	%	38	%	14	%	6	%	4	%	2	%	1	%	1	%	—	%	—	%

Prior Period Development — Supplementary Information

The following table presents a reconciliation of the loss development triangles above to prior period development:


	Components of PPD
Year Ended December 31, 2020 (in millions of U.S. dollars) (favorable)/unfavorable	2011 - 2019 accident years (implied PPD per loss triangles)		Accident years prior to 2011		Other (1)			PPD on loss reserves		RIPs, Expense adjustments, and earned premiums			Total
North America Commercial P&C Insurance
Long-tail	$	(354)	$	(247)	$	(102)		$	(703)	$	31		$	(672)
Short-tail	(37)		2		5			(30)		—			(30)
	(391)		(245)		(97)		(2)	(733)		31		(3)	(702)
North America Personal P&C Insurance (Short-tail)	85		(1)		(3)			81		(18)			63
Overseas General Insurance
Long-tail	9		(59)		1			(49)		—			(49)
Short-tail	(69)		(8)		(24)			(101)		—			(101)
	(60)		(67)		(23)		(4)	(150)		—			(150)
Global Reinsurance
Long-tail	(12)		(10)		(1)			(23)		(2)			(25)
Short-tail	(2)		—		(1)			(3)		(1)			(4)
	(14)		(10)		(2)			(26)		(3)			(29)
Subtotal	$	(380)	$	(323)	$	(125)		$	(828)	$	10		$	(818)
North America Agricultural Insurance (Short-tail)								$	(19)	$	9		$	(10)
Corporate (Long-tail)								433		—			433
Consolidated PPD								$	(414)	$	19		$	(395)

(1) Other includes the impact of foreign exchange.

(2) Includes favorable development of $80 million related to our Alternative Risk Solutions business (U.S. and Bermuda) and an adjustment to exclude $15 million in unfavorable development in the workers' compensation line, associated with an increase in exposure for which additional premiums were collected; the remaining difference relates to a number of other items, none of which are individually material.

(3) Includes premium returns associated with our Alternative Risk Solutions business, which is excluded from the triangles.

(4) Includes favorable development of $22 million related to International A&H business; the remaining difference relates to a number of other items, none of which are individually material.

Prior Period Development

Prior period development (PPD) arises from changes to loss estimates recognized in the current year that relate to loss events that occurred in previous calendar years and excludes the effect of losses from the development of earned premium from previous accident years. Long-tail lines include lines such as workers' compensation, general liability, and professional liability; while short-tail lines include lines such as most property lines, energy, personal accident, and agriculture. The following table summarizes (favorable) and adverse PPD by segment:


Years Ended December 31 (in millions of U.S. dollars, except for percentages)	Long-tail		Short-tail		Total		% of beginning net unpaid reserves (1)
2020
North America Commercial P&C Insurance	$	(672)	$	(30)	$	(702)	1.4	%
North America Personal P&C Insurance	—		63		63		0.1	%
North America Agricultural Insurance	—		(10)		(10)		—	%
Overseas General Insurance	(49)		(101)		(150)		0.3	%
Global Reinsurance	(25)		(4)		(29)		0.1	%
Corporate	433		—		433		0.9	%
Total	$	(313)	$	(82)	$	(395)	0.8	%
2019
North America Commercial P&C Insurance	$	(668)	$	19	$	(649)	1.3	%
North America Personal P&C Insurance	—		(95)		(95)		0.2	%
North America Agricultural Insurance	—		(80)		(80)		0.2	%
Overseas General Insurance	(68)		(24)		(92)		0.2	%
Global Reinsurance	(59)		30		(29)		0.1	%
Corporate	153		—		153		0.3	%
Total	$	(642)	$	(150)	$	(792)	1.6	%
2018
North America Commercial P&C Insurance	$	(395)	$	(215)	$	(610)	1.2	%
North America Personal P&C Insurance	—		41		41		0.1	%
North America Agricultural Insurance	—		(110)		(110)		0.2	%
Overseas General Insurance	(67)		(145)		(212)		0.4	%
Global Reinsurance	(69)		19		(50)		0.1	%
Corporate	45		—		45		0.1	%
Total	$	(486)	$	(410)	$	(896)	1.8	%

(1) Calculated based on the beginning of period consolidated net unpaid losses and loss expenses.

Significant prior period movements by segment, principally driven by reserve reviews completed during each respective period, are discussed in more detail below. The remaining net development for long-tail lines and short-tail business for each segment and Corporate comprises numerous favorable and adverse movements across a number of lines and accident years, none of which is significant individually or in the aggregate.

North America Commercial P&C Insurance

2020

North America Commercial P&C Insurance experienced net favorable PPD of $702 million, which was the net result of several underlying favorable and adverse movements, and was driven by the following principal changes:

•Net favorable development of $672 million in long-tail business, primarily from:

•Net favorable development of $363 million in workers’ compensation lines. The majority of the favorable development related to accident years 2016 and prior, driven by lower than expected loss emergence and related updates to loss development factors. In addition, we experienced favorable development of $62 million related to our annual assessment of multi-claimant events, including industrial accidents, in the 2019 accident year. Consistent with prior

years, we reviewed these potential exposures after the close of the accident year to allow for late reporting or identification of significant losses. This favorable development in accident year 2019 was partially offset by some higher than expected activity from other claims;

•Net favorable development of $231 million in management liability portfolios, favorably impacting accident years 2015 and prior where paid and reported loss activity was lower than expected, partially offset by adverse development in the 2016 through 2019 accident years, mainly due to higher than expected claim severity in our Directors and Officers (D&O) portfolios;

•Net favorable development of $83 million in commercial excess and umbrella portfolios, mainly in accident years 2014 and prior, driven by lower paid and reported loss activity relative to prior expectations as well as an increase in weighting towards experience-based methods, partially offset by adverse development in more recent accident years, due to higher than expected loss activity;

•Net favorable development of $67 million in professional liability (errors & omissions and cyber risk), driven by accident years 2016 and prior, which experienced lower than expected loss emergence;

•Net favorable development of $43 million in voluntary environmental lines, in accident years 2016 and prior, due to lower than expected loss emergence and a related update to loss development factors;

•Net favorable development of $41 million on large multi-line prospective deals in the 2016 and prior accident years, due to lower than expected reported loss activity. These structured deals typically cover large clients for multiple product lines and with varying loss limitations; this development is net of premium returns of $26 million tied to the loss performance of the particular deals;

•Net favorable development of $40 million in foreign casualty businesses, mainly in accident year 2016, due to lower than expected reported loss activity, partially offset by adverse development on a large loss in accident year 2017;

•Net adverse development of $48 million in general liability coverages, driven by higher than expected reported loss activity in accident years 2017 through 2019, partially offset by favorable development in older accident years;

•Net adverse development of $64 million in medical liability businesses, mainly impacting accident years 2016 through 2019, primarily due to higher than expected reported loss emergence and associated changes to loss development factors and loss expectations; and

•Net adverse development of $77 million in commercial automobile liability, mainly in high deductible and excess portfolios, driven by adverse paid and reported loss emergence and related updates to loss development factors, mainly in accident years 2015 through 2019.

•Net favorable development of $30 million in short-tail business primarily from:

•Net favorable development of $37 million, in accident & health, mainly in accident years 2018 and 2019, driven by lower than expected paid loss emergence;

•Net favorable development of $31 million in surety businesses, driven by accident year 2018, where loss emergence was lower than expected; and

•Net adverse development of $21 million in our marine portfolios, mainly impacting the 2019 accident year, driven by higher than expected non-catastrophe loss development.

2019

North America Commercial P&C Insurance experienced net favorable PPD of $649 million, which was the net result of several underlying favorable and adverse movements, and was driven by the following principal changes:

•Net favorable development of $668 million in long-tail business, primarily from:

•Net favorable development of $303 million in workers’ compensation lines. This included favorable development of $61 million related to our annual assessment of multi-claimant events including industrial accidents, in the 2018 accident year. Consistent with prior years, we reviewed these potential exposures after the close of the accident year to allow for late reporting or identification of significant losses. This development in accident year 2018 was partially

offset by some higher than expected activity from other claims and from involuntary pools. The remaining overall favorable development was mainly in accident years 2015 and prior, generally driven by lower than expected loss experience and related updates to loss development factors;

•Net favorable development of $217 million in management liability portfolios, favorably impacting accident years 2015 and prior where paid and reported loss activity was lower than expected, partially offset by adverse development in the 2016 through 2018 accident years, mostly as a result of higher severity claim costs compared to prior expectations in certain lines or coverages, particularly in our Directors and Officers (D&O) portfolios;

•Net favorable development of $60 million in professional liability (errors & omissions and cyber), mainly in the 2015 and prior accident years where case activity was less than expected, partially offset by adverse development in the 2016 accident year, which was driven by several large adverse claim developments;

•Net favorable development of $41 million in commercial excess and umbrella portfolios, mainly in accident years 2013 and prior driven by lower paid and reported loss activity relative to prior expectations as well as an increase in weighting towards experience-based methods, partly offset by modestly adverse development in more recent accident years, mainly in 2017 and 2018, due to higher than expected large loss activity;

•Net favorable development of $39 million in foreign casualty business, impacting accident years 2015 and prior, driven by reported loss activity that was generally lower than expected;

•Net favorable development of $36 million on large multi-line prospective deals in the 2015 and prior accident years, due to lower than expected reported loss activity. These structured deals typically cover large clients for multiple product lines and with varying loss limitations; this development is net of premium returns of $34 million tied to the loss performance of the particular deals;

•Net favorable development of $24 million in medical and life sciences businesses, mainly impacting accident years 2015 and prior, primarily due to favorable reported experience and an increase in weighting towards experience-based methods;

•Favorable development of $23 million in political risk and trade credit portfolios, mainly impacting the 2015 accident year, primarily due to favorable reported experience and an increase in weighting towards experience-based methods;

•Net adverse development of $26 million mainly in products and general liability portfolios, including adverse movements within construction, partly offset by commercial-multi peril (CMP) liability, with older accident years generally experiencing favorable run-off, while more recent accident years developing adversely; and

•Net adverse development of $38 million in automobile liability, driven by adverse paid and reported loss experience mainly in accident years 2014 through 2018.

•Net adverse development of $19 million in short-tail business, primarily from:

•Net adverse development, excluding catastrophes, of $108 million in property and marine portfolios with adverse development of $152 million across our retail, wholesale, and program distribution channels in accident year 2018, primarily due to a higher than expected severity of non-catastrophe claims, partly offset by favorable development of $44 million in 2017 and prior accident years on non-catastrophe claims;

•Net favorable catastrophe development in property and marine portfolios of $36 million. There was $41 million of favorable development on the 2017 and 2018 natural catastrophes, mostly in 2017, partly offset by some adverse development on older catastrophe events; and

•Favorable development of $49 million in surety businesses, mainly in accident year 2017, driven by lower than expected reported loss activity.

2018

North America Commercial P&C Insurance experienced net favorable PPD of $610 million, representing 1.2 percent of the beginning consolidated net unpaid losses and loss expense reserves.

North America Personal P&C Insurance

2020

North America Personal P&C Insurance incurred net adverse PPD of $63 million, which was the net result of several underlying favorable and adverse movements, and was driven by the following principal changes:

•Net adverse development of $84 million in the homeowners product line, including valuables, mainly in accident years 2017 through 2019 due to higher than expected non-catastrophe loss emergence and adverse development arising from natural catastrophes in accident years 2017 and 2018; and

•Net favorable development of $22 million in the personal excess line, driven by favorable development mainly in the 2017 accident year, partially offset by adverse development in accident year 2019.

2019

North America Personal P&C Insurance incurred net favorable PPD of $95 million, which was the net result of several underlying favorable and adverse movements, and was driven by the following principal changes:

•Net favorable claim development of $132 million on the 2017 and 2018 natural catastrophes for all lines;

•Net favorable development of $26 million in our personal excess lines primarily impacting the 2016 accident year, due to lower than expected loss emergence and an increase in weighting towards experience-based methods, partly offset by adverse emergence in accident year 2015; and

•Net adverse development of $82 million in our homeowners lines, including valuables, arising from non-catastrophe loss emergence, mainly in the 2018 accident year.

2018

North America Personal P&C Insurance incurred net adverse PPD of $41 million, representing 0.1 percent of the beginning consolidated net unpaid losses and loss expense reserves.

North America Agricultural Insurance

North America Agricultural Insurance experienced net favorable PPD of $10 million, $80 million, and $110 million in 2020, 2019, and 2018, respectively. Actual claim development mainly relates to our Multiple Peril Crop Insurance business and was favorable due to better than expected crop yield results in certain states at the prior year-end period (i.e., 2020 results based on crop yield results at year-end 2019).

Overseas General Insurance

2020

Overseas General Insurance experienced net favorable PPD of $150 million which was the net result of several underlying favorable and adverse movements, and was driven by the following principal changes:

•Net favorable development of $49 million in long-tail business, primarily from:

•Net favorable development of $94 million in casualty lines, including favorable development of $143 million in accident years 2016 and prior, due to lower than expected loss emergence across primary and excess lines in Continental Europe, U.K., and Asia Pacific, partially offset by adverse development of $49 million in accident years 2017 through 2019, primarily due to adverse large loss experience in U.K. and Asia Pacific;

•Net favorable development of $22 million in political risk, driven by lower than expected loss emergence in accident years 2018 and 2019; and

•Net adverse development of $80 million in financial lines, with favorable development of $61 million in accident years 2015 and prior, primarily from favorable case-specific settlements within Continental Europe and Asia Pacific financial institutions, which was more than offset by adverse development of $141 million in accident years 2016 through 2019, primarily due to adverse large loss experience in D&O portfolios in the U.K. and Asia Pacific.

•Net favorable development of $101 million in short-tail business, primarily from:

•Net favorable development of $69 million in marine, driven by favorable loss emergence and claim-specific loss settlements across all regions in accident years 2012 through 2019; and

•Net favorable development of $21 million in A&H, driven by favorable development across Continental Europe, U.K. and Latin America primarily in accident years 2018 and 2019.

2019

Overseas General Insurance experienced net favorable PPD of $92 million, which was the net result of several underlying favorable and adverse movements, and was driven by the following principal changes:

•Net favorable development of $68 million in long-tail business, primarily from:

•Net favorable development of $101 million in casualty lines, including favorable development of $123 million in accident years 2015 and prior, due to lower than expected loss emergence mainly across primary lines in Continental Europe, U.K., and Asia Pacific, partially offset by adverse development of $22 million in accident years 2016 through 2018, primarily due to adverse attritional and large loss experience in Continental Europe; and

•Net adverse development of $52 million in financial lines, including adverse development of $127 million in accident years 2016 through 2018, primarily due to adverse large loss experience in D&O in the U.K. and Asia Pacific, offset by favorable development of $75 million in accident years 2015 and prior, due to lower than expected loss emergence across most regions in D&O and Professional Indemnity.

•Net favorable of $24 million in short-tail business, primarily from:

•Net favorable development of $45 million in A&H, driven by favorable development across Continental Europe, Latin America and Asia Pacific primarily in accident years 2017 and 2018;

•Net favorable development of $36 million in marine, driven by favorable loss emergence and claim-specific loss settlements across most regions and several accident years, including favorable liability emergence and litigation settlements in accident years 2016 and prior;

•Net adverse development of $23 million in construction, driven by adverse large loss experience in accident year 2018 for U.K. and Asia Pacific; and

•Net adverse development of $27 million in Surety, driven by adverse large loss experience across Continental Europe and Latin America in accident years 2017 and 2018.

2018

Overseas General Insurance experienced net favorable PPD of $212 million, representing 0.4 percent of the beginning consolidated net unpaid losses and loss expense reserves.

Global Reinsurance

2020

Global Reinsurance experienced net favorable PPD of $29 million, which was the net result of several underlying favorable and adverse movements, none of which is significant individually or in the aggregate.

2019

Global Reinsurance experienced net favorable PPD of $29 million, which was the net result of several underlying favorable and adverse movements, and was driven by the following principal changes:

•Net favorable development of $59 million in long-tail business, primarily in our auto, casualty, professional liability, medical malpractice, and workers’ compensation lines primarily from treaty years 2013 and prior principally due to lower than expected loss emergence; and

•Net adverse development of $30 million in short-tail business, which included $44 million of adverse development on 2017 and 2018 natural catastrophe events.

2018

Global Reinsurance experienced net favorable PPD of $50 million, representing 0.1 percent of the beginning consolidated net unpaid losses and loss expense reserves.

Corporate

2020

Corporate incurred adverse development of $433 million in long-tail lines, driven by the following principal changes:

•Adverse development of $254 million for U.S. child molestation claims, predominantly reviver statute-related;

•Adverse development of $106 million associated with asbestos and environmental liabilities, generally attributable to certain case specific incurred activity and higher than expected indemnity, expenses and defense costs on a limited number of accounts;

•Adverse development of $38 million on unallocated loss adjustment expenses due to run-off operating expenses paid and incurred in 2020 and $27 million from an increase in the provision for uncollectible reinsurance.

2019

Corporate incurred adverse development of $153 million in long-tail lines, driven by the following principal changes:

•Adverse development of $116 million driven principally by adverse development in asbestos and environmental liabilities due to the emergence of a limited number of excess accounts and somewhat greater than expected defense and indemnity costs (generally impacting larger modeled accounts); and

•Adverse development of $37 million on unallocated loss adjustment expenses due to run-off operating expenses paid and incurred in 2019.

2018

Corporate incurred adverse PPD of $45 million, representing 0.1 percent of the beginning consolidated net unpaid losses and loss expense reserves.

Asbestos and environmental (A&E)

Chubb's exposure to A&E claims principally arises out of liabilities acquired when it purchased Westchester Specialty in 1998, CIGNA's P&C business in 1999, and Chubb Corp in 2016. The following table presents a roll-forward of consolidated A&E loss reserves including allocated loss expense reserves for A&E exposures, and the valuation allowance for uncollectible paid and unpaid reinsurance recoverables:


	Asbestos				Environmental				Total
(in millions of U.S. dollars)	Gross		Net		Gross		Net		Gross		Net
Balance at December 31, 2017	$	1,621	$	1,051	$	607	$	476	$	2,228	$	1,527
Incurred activity	136		75		101		(97)		237		(22)		(1)
Paid activity	(265)		(162)		(83)		104		(348)		(58)
Balance at December 31, 2018	1,492		964		625		483		2,117		1,447
Incurred activity	129		70		46		28		175		98		(1)
Paid activity	(162)		(118)		(142)		(101)		(304)		(219)
Balance at December 31, 2019	1,459		916		529		410		1,988		1,326
Incurred activity	150		90		79		41		229		131		(1)
Paid activity	(258)		(133)		(91)		(72)		(349)		(205)
Balance at December 31, 2020	$	1,351	$	873	$	517	$	379	$	1,868	$	1,252

(1) Excludes unallocated loss expenses and the net activity reflects third-party reinsurance other than the aggregate excess of loss reinsurance provided by National Indemnity Company (NICO) to Westchester Specialty (see Westchester Specialty section below).

The A&E net loss reserves including allocated loss expense reserves and valuation allowance for uncollectible reinsurance at December 31, 2020 and 2019 shown in the table above is comprised of:


	December 31
(in millions of U.S. dollars)	2020		2019
Brandywine operations	$	736	$	754
Westchester Specialty	103		117
Chubb Corp	333		381
Other, mainly Overseas General Insurance	80		74
Total	$	1,252	$	1,326

Brandywine Run-off entities – The Restructuring Plan and uncertainties relating to Chubb's ultimate Brandywine exposure

In 1996, the Pennsylvania Insurance Commissioner approved a plan to restructure INA Financial Corporation and its subsidiaries (the Restructuring) which included the division of Insurance Company of North America (INA) into two separate corporations:

(1) An active insurance company that retained the INA name and continued to write P&C business; and

(2) An inactive run-off company, now called Century Indemnity Company (Century).

As a result of the division, predominantly all A&E and certain other liabilities of INA were ascribed to Century and extinguished, as a matter of Pennsylvania law, as liabilities of INA.

As part of the Restructuring, most A&E liabilities of various U.S. affiliates of INA were reinsured to Century. Century and certain other run-off companies having A&E and other liabilities were contributed to Brandywine Holdings.

The U.S.-based Chubb INA companies assumed two contractual obligations in respect of the Brandywine operations in connection with the Restructuring: a surplus maintenance obligation in the form of the excess of loss (XOL) agreement and a dividend retention fund obligation.

XOL Agreement

In 1996, in connection with the Restructuring, a Chubb INA insurance subsidiary provided reinsurance coverage to Century in the amount of $800 million under an Aggregate Excess of Loss Reinsurance Agreement (XOL Agreement), triggerable if the statutory capital and surplus of Century falls below $25 million or if Century lacks liquid assets with which to pay claims as they become due.

Dividend Retention Fund

INA Financial Corporation established and funded a dividend retention fund (the Dividend Retention Fund) consisting of $50 million plus investment earnings. The full balance of the Dividend Retention Fund was contributed to Century as of December 31, 2002. Under the Restructuring Order, while any obligation to maintain the Dividend Retention Fund is in effect, to the extent dividends are paid by INA Holdings Corporation to its parent, INA Financial Corporation, and to the extent INA Financial Corporation then pays such dividends to INA Corporation, a portion of those dividends must be withheld to replenish the principal of the Dividend Retention Fund to $50 million. During 2020, 2019, 2018, 2011 and 2010, $250 million, $90 million, $50 million, $35 million and $15 million, respectively, were withheld from such dividends and deposited into the Dividend Retention Fund as a result of dividends paid up to the INA Corporation. Pursuant to a 2011 amendment to the Restructuring Order, capital contributions from the Dividend Retention Fund to Century are not required until the XOL Agreement has less than $200 million of capacity remaining on an incurred basis for statutory reporting purposes. The amount of the required capital contribution shall be the lesser of the amount necessary to restore the XOL Agreement remaining capacity to $200 million or the Dividend Retention Fund balance. In 2020 and 2019, capital contributions of $302 million and $64 million were made, respectively, from the Dividend Retention Fund to Century. The Dividend Retention Fund may not be terminated without prior written approval from the Pennsylvania Insurance Commissioner.

Effective December 31, 2004, Chubb INA contributed $100 million to Century in exchange for a surplus note. After giving effect to the contribution and issuance of the surplus note, the statutory surplus of Century at December 31, 2020 was $25 million and $573 million in statutory-basis losses have been ceded to the XOL Agreement on an inception-to-date basis. Century reports the amount ceded under the XOL Agreement in accordance with statutory accounting principles, which differ from GAAP

by, among other things, allowing Century to discount its liabilities, including certain asbestos related and environmental pollution liabilities and Century's reinsurance payable to active companies. For GAAP reporting purposes, intercompany reinsurance recoverables related to the XOL are eliminated upon consolidation.

While Chubb believes it has no legal obligation to fund Century losses above the XOL limit of coverage, Chubb's consolidated results would nevertheless continue to include any losses above the limit of coverage for so long as the Brandywine companies remain consolidated subsidiaries of Chubb.

Certain active Chubb companies are primarily liable for asbestos, environmental, and other exposures that they have reinsured to Century. Accordingly, if Century were to become insolvent and placed into rehabilitation or liquidation, some or all of the recoverables due to these active Chubb companies from Century could become uncollectible. At December 31, 2020 and 2019, the aggregate reinsurance recoverables owed by Century to certain active Chubb companies were approximately $1.6 billion and $1.5 billion, respectively, on an undiscounted basis. Chubb believes the active company intercompany reinsurance recoverables, which relate to direct liabilities payable over many years, are not impaired. At December 31, 2020 and 2019, Century's carried gross reserves (including reserves assumed from the active Chubb companies) were $2.1 billion and $1.8 billion, respectively. Should Century's loss reserves experience adverse development in the future and should Century be placed into rehabilitation or liquidation, the reinsurance recoverables due from Century to certain active Chubb companies would be payable only after the payment in full of certain expenses and liabilities, including administrative expenses and direct policy liabilities. Thus, the intercompany reinsurance recoverables would be at risk to the extent of the shortage of assets remaining to pay these recoverables.

Westchester Specialty – impact of NICO contracts on Chubb’s run-off entities

As part of the Westchester Specialty acquisition in 1998, NICO provided a 75 percent pro-rata share of $1.0 billion of reinsurance protection on losses and loss adjustment expenses incurred on or before December 31, 1996, in excess of a retention of $721 million. At December 31, 2020, the remaining unused incurred limit under the Westchester NICO agreement was $372 million.

Taxation

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Taxation

Under Swiss law through December 31, 2020, a resident company is subject to income tax at the federal, cantonal, and communal levels that is levied on net worldwide income. Income attributable to permanent establishments or real estate located abroad is excluded from the Swiss tax base. Furthermore, participation relief (i.e., tax relief) is granted to Chubb Limited at the federal, cantonal, and communal level for qualifying dividend income and capital gains related to the sale of qualifying participations (i.e., subsidiaries). Chubb Limited is subject to an annual cantonal and communal capital tax on the taxable equity of Chubb Limited in Switzerland.

Chubb has two Swiss operating subsidiaries, an insurance company, Chubb Insurance (Switzerland) Limited and a reinsurance company, Chubb Reinsurance (Switzerland) Limited. Both are subject to federal, cantonal, and communal income tax and to annual cantonal and communal capital tax.

Under current Bermuda law, Chubb Limited and its Bermuda subsidiaries are not required to pay any taxes on income or capital gains. If a Bermuda law were enacted that would impose taxes on income or capital gains, Chubb Limited and the Bermuda subsidiaries have received an undertaking from the Minister of Finance in Bermuda that would exempt such companies from Bermudian taxation until March 2035.

Income from Chubb's operations at Lloyd's is subject to United Kingdom (U.K.) corporation income taxes. Lloyd's is required to pay U.S. income tax on U.S. connected income written by Lloyd's syndicates. Lloyd's has a closing agreement with the Internal Revenue Service (IRS) whereby the amount of tax due on this business is calculated by Lloyd's and remitted directly to the IRS. These amounts are then charged to the accounts of Chubb's Corporate Members in proportion to their participation in the relevant syndicates. Chubb's Corporate Members are subject to this arrangement but, as U.K. domiciled companies, will receive U.K. corporation tax credits for any U.S. income tax incurred up to the value of the equivalent U.K. corporation income tax charge on this income.

Chubb Group Holdings and its respective subsidiaries are subject to income taxes imposed by U.S. authorities and file a consolidated U.S. Federal income tax return. Should Chubb Group Holdings pay a dividend to Chubb Limited, withholding taxes

would apply. Currently, however, no withholding taxes are accrued with respect to such un-remitted earnings as management has no intention of remitting these earnings. Similarly, no taxes have been provided on the un-remitted earnings of certain foreign subsidiaries (Hong Kong and Korea life insurance companies) as management has no intention of remitting these earnings. The cumulative amount that would be subject to withholding tax, if distributed, as well as the determination of the associated tax liability are not practicable to compute; however, such amount would be material.

Certain international operations of Chubb are also subject to income taxes imposed by the jurisdictions in which they operate.

Chubb's domestic operations are in Switzerland, the jurisdiction where we are legally organized, incorporated, and registered. As a result of Swiss tax reform legislation effective in 2020, the Swiss tax rate increased from 7.83 percent in years 2018 and 2019 to 21.2 percent in 2020.

The following table presents pre-tax income and the related provision for income taxes:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Pre-tax income:
Switzerland	$	350	$	440	$	950
Outside Switzerland	3,812		4,809		3,707
Total pre-tax income	$	4,162	$	5,249	$	4,657
Provision for income taxes
Current tax expense:
Switzerland	$	52	$	29	$	89
Outside Switzerland	876		879		563
Total current tax expense	928		908		652
Deferred tax expense (benefit):
Switzerland	2		11		3
Outside Switzerland	(301)		(124)		40
Total deferred tax expense (benefit)	(299)		(113)		43
Provision for income taxes	$	629	$	795	$	695

The most significant jurisdictions contributing to the overall taxation of Chubb are calculated using the following rates in 2020: Switzerland 21.2 percent, U.S. 21.0 percent, U.K. 19.0 percent, and Bermuda 0.0 percent.

The following table presents a reconciliation of the difference between the provision for income taxes and the expected tax provision at the Swiss statutory income tax rate:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Expected tax provision at Swiss statutory tax rate	$	880	$	411	$	365
Permanent differences:
Taxes on earnings subject to rate other than Swiss statutory rate	(337)		376		372
Tax-exempt interest and dividends received deduction, net of proration	(41)		(49)		(75)
Net withholding taxes	67		40		33
Share-based compensation	(10)		(12)		(19)
Impact of 2017 Tax Act	—		—		(25)
Other	70		29		44
Provision for income taxes	$	629	$	795	$	695

The following table presents the components of net deferred tax assets and liabilities:


	December 31		December 31
(in millions of U.S. dollars)	2020		2019
Deferred tax assets:
Loss reserve discount	$	884	$	826
Unearned premiums reserve	496		519
Foreign tax credits	222		247
Provision for uncollectible balances	46		37
Loss carry-forwards	123		143
Debt related amounts	69		74
Compensation related amounts	281		261
Cumulative translation adjustments	120		33
Investments	75		—
Lease liability	121		140

Total deferred tax assets	2,437		2,280
Deferred tax liabilities:
Deferred policy acquisition costs	522		588
Other intangible assets, including VOBA	1,425		1,468
Un-remitted foreign earnings	77		73
Investments	—		40
Unrealized appreciation on investments	957		470
Depreciation	123		157
Lease right-of-use asset	111		129
Other, net	31		45
Total deferred tax liabilities	3,246		2,970
Valuation allowance	83		114
Net deferred tax liabilities	$	(892)	$	(804)

The valuation allowance of $83 million and $114 million at December 31, 2020 and 2019, respectively, reflects management's assessment, based on available information, that it is more likely than not that a portion of the deferred tax assets will not be realized due to the inability of certain non-U.S. subsidiaries to generate sufficient taxable income. Adjustments to the valuation allowance are made when there is a change in management's assessment of the amount of deferred tax assets that are realizable.

At December 31, 2020, Chubb has net operating loss carry-forwards of $407 million which, if unused, will expire starting in 2021, and a foreign tax credit carry-forward in the amount of $222 million which, if unused, will expire starting in 2026.

The following table presents a reconciliation of the beginning and ending amount of gross unrecognized tax benefits:


	December 31		December 31
(in millions of U.S. dollars)	2020		2019
Balance, beginning of year	$	47	$	14
Additions based on tax positions related to the current year	5		12
Additions based on tax positions related to prior years	24		23


Reductions for the lapse of the applicable statutes of limitations	—		(2)
Balance, end of year	$	76	$	47

At December 31, 2020 and 2019, the gross unrecognized tax benefits of $76 million and $47 million, respectively, can be reduced by $31 million and $19 million, respectively, associated with foreign tax credits. The net amounts of $45 million and $28 million at December 31, 2020 and 2019, respectively, if recognized, would favorably affect the effective tax rate. We

made a settlement of a liability in January 2021 for $23 million, including interest. It is reasonably possible that over the next twelve months, that the amount of unrecognized tax benefits may change further resulting from the re-evaluation of unrecognized tax benefits arising from examinations by taxing authorities and the lapses of statutes of limitations.

Chubb recognizes accruals for interest and penalties, if any, related to unrecognized tax benefits in income tax expense in the Consolidated statements of operations. Tax-related interest expense and penalties reported in the Consolidated statements of operations were $8 million at December 31, 2020, $5 million at December 31, 2019, and were immaterial for 2018. Liabilities for tax-related interest and penalties in our Consolidated balance sheets were $16 million and $8 million at December 31, 2020 and 2019, respectively.

In March 2017, the IRS commenced its field examination of Chubb Group Holdings’ U.S. Federal income tax returns for 2014 and 2015. The Chubb Group Holdings examination for 2014 and 2015 tax years is still ongoing with no material adjustments proposed to date. In July 2020, the IRS commenced its field examination of Chubb Group Holdings' U.S. Federal income tax returns for 2016, 2017 and 2018. As a multinational company, we also have examinations under way in several foreign jurisdictions. With few exceptions, Chubb is no longer subject to income tax examinations for years prior to 2010.

The following table summarizes tax years open for examination by major income tax jurisdiction:


At December 31, 2020
Australia	2014	-	2020
Canada	2012	-	2020
France	2018	-	2020
Germany	2015	-	2020
Italy	2010	-	2020
Mexico	2014	-	2020
Spain	2012	-	2020
Switzerland	2016	-	2020
United Kingdom	2015	-	2020
United States	2014	-	2020

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

Commitments and Contingencies Disclosure [Abstract]

Debt

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Debt


	December 31		December 31
(in millions of U.S. dollars)	2020		2019		Early Redemption Option
Repurchase agreements (weighted average interest rate of 0.3% in 2020 and 2.2% in 2019)	$	1,405	$	1,416	None
Short-term debt
Chubb INA:
$1,300 million 2.3% due November 2020	$	—	$	1,298	Make-whole premium plus 15 bps
Other short-term debt 2.75% due September 2020	—		1		None
Total short-term debt	$	—	$	1,299
Long-term debt
Chubb INA:
$1,000 million 2.875% senior notes due November 2022	$	998	$	997	Make-whole premium plus 20 bps
$475 million 2.7% senior notes due March 2023	474		473		Make-whole premium plus 10 bps
$700 million 3.35% senior notes due May 2024	698		697		Make-whole premium plus 15 bps
€700 million 0.3% senior notes due December 2024	841		776		Make-whole premium plus 15 bps
$800 million 3.15% senior notes due March 2025	797		796		Make-whole premium plus 15 bps
$1,500 million 3.35% senior notes due May 2026	1,493		1,492		Make-whole premium plus 20 bps
€575 million 0.875% senior notes due June 2027	691		635		Make-whole premium plus 20 bps
€900 million 1.55% senior notes due March 2028	1,079		993		Make-whole premium plus 15 bps
$100 million 8.875% debentures due August 2029	100		100		None
€700 million 0.875% senior notes due December 2029	840		775		Make-whole premium plus 20 bps
$1,000 million 1.375% senior notes due September 2030	991		—		Make-whole premium plus 15 bps
€575 million 1.4% senior notes due June 2031	687		633		Make-whole premium plus 25 bps
$200 million 6.8% debentures due November 2031	242		246		Make-whole premium plus 25 bps
$300 million 6.7% senior notes due May 2036	298		297		Make-whole premium plus 20 bps
$800 million 6.0% senior notes due May 2037	945		953		Make-whole premium plus 20 bps
€900 million 2.5% senior notes due March 2038	1,077		992		Make-whole premium plus 25 bps
$600 million 6.5% senior notes due May 2038	743		751		Make-whole premium plus 30 bps
$475 million 4.15% senior notes due March 2043	470		470		Make-whole premium plus 15 bps
$1,500 million 4.35% senior notes due November 2045	1,484		1,483		Make-whole premium plus 25 bps
Total long-term debt	$	14,948	$	13,559
Trust preferred securities
Chubb INA capital securities due April 2030	$	308	$	308	Redemption prices(1)

(1)Redemption prices are equal to accrued and unpaid interest to the redemption date plus the greater of (i) 100 percent of the principal amount thereof, or (ii) sum of present value of scheduled payments of principal and interest on the capital securities from the redemption date to April 1, 2030.

a) Repurchase agreements

Chubb has executed repurchase agreements with certain counterparties under which Chubb agreed to sell securities and repurchase them at a future date for a predetermined price.

b) Short-term debt

Short-term debt comprises the current maturities of our long-term debt instruments described below. These short-term debt instruments were reclassified from long-term debt and are reflected in the table above. Chubb INA Holdings Inc.'s (Chubb INA) $1,300 million of 2.3 percent senior notes due November 2020 was paid upon maturity.

c) Long-term debt

The $100 million of 8.875 percent debentures due August 2029 do not have an early redemption option. The remaining Chubb INA senior notes and debentures, including the $1,000 million of 1.375 percent senior notes issued September 2020, and capital securities are redeemable at any time at Chubb INA's option subject to the provisions described in the table above. A "make-whole" premium is the present value of the remaining principal and interest discounted at the applicable U.S. Treasury rate. These debt securities are also redeemable at par plus accrued and unpaid interest in the event of certain changes in tax law.

The senior notes and debentures do not have the benefit of any sinking fund and are guaranteed on a senior basis by Chubb Limited and they rank equally with all of Chubb's other senior obligations. They also contain customary limitations on lien provisions as well as customary events of default provisions which, if breached, could result in the accelerated maturity of such senior debt.

d) Trust preferred securities

In March 2000, ACE Capital Trust II, a Delaware statutory business trust, publicly issued $300 million of 9.7 percent Capital Securities (the Capital Securities) due to mature in April 2030. At the same time, Chubb INA purchased $9.2 million of common securities of ACE Capital Trust II. The sole assets of ACE Capital Trust II consist of $309 million principal amount of 9.7 percent Junior Subordinated Deferrable Interest Debentures (the Subordinated Debentures) issued by Chubb INA due to mature in April 2030.

Distributions on the Capital Securities are payable semi-annually and may be deferred for up to ten consecutive semi-annual periods (but no later than April 1, 2030). Any deferred payments would accrue interest compounded semi-annually if Chubb INA defers interest on the Subordinated Debentures. Interest on the Subordinated Debentures is payable semi-annually. Chubb INA may defer such interest payments (but no later than April 1, 2030), with such deferred payments accruing interest compounded semi-annually. The Capital Securities and the ACE Capital Trust II Common Securities will be redeemed upon repayment of the Subordinated Debentures.

Chubb Limited has guaranteed, on a subordinated basis, Chubb INA's obligations under the Subordinated Debentures, and distributions and other payments due on the Capital Securities. These guarantees, when taken together with Chubb's obligations under expense agreements entered into with ACE Capital Trust II, provide a full and unconditional guarantee of amounts due on the Capital Securities.

Commitments, contingencies, and guarantees

12 Months Ended

Dec. 31, 2020

Commitments, contingencies, and guarantees

a) Derivative instruments

Foreign currency management

As a global company, Chubb entities transact business in multiple currencies. Our policy is to generally match assets, liabilities, and required capital for each individual jurisdiction in local currency, which would include the use of derivatives discussed below. We do not hedge our net asset non-U.S. dollar capital positions; however, we do consider economic hedging for planned cross border transactions.

Derivative instruments employed

Chubb maintains positions in derivative instruments such as futures, options, swaps, and foreign currency forward contracts for which the primary purposes are to manage duration and foreign currency exposure, yield enhancement, or to obtain an exposure to a particular financial market. Chubb also maintains positions in convertible securities that contain embedded derivatives. Investment derivative instruments are recorded in either Other assets (OA) or Accounts payable, accrued expenses, and other liabilities (AP), convertible bonds are recorded in Fixed maturities available for sale (FM AFS), and convertible equity securities are recorded in Equity securities (ES) in the Consolidated balance sheets. These are the most numerous and frequent derivative transactions. In addition, Chubb purchases to be announced mortgage-backed securities (TBAs) as part of its investing activities.

Under reinsurance programs covering GLBs, Chubb assumes the risk of GLBs, principally GMIB, associated with variable annuity contracts. The GMIB risk is triggered if, at the time the contract holder elects to convert the accumulated account value to a periodic payment stream (annuitize), the accumulated account value is not sufficient to provide a guaranteed minimum level of monthly income. The GLB reinsurance product meets the definition of a derivative instrument and is classified within AP. Chubb also generally maintains positions in exchange-traded equity futures contracts on equity market indices to limit equity exposure in the GMDB and GLB book of business. All derivative instruments are carried at fair value with changes in fair value recorded in Net realized gains (losses) in the Consolidated statements of operations. None of the derivative instruments are designated as hedges for accounting purposes. The following table presents the balance sheet locations, fair values of derivative instruments in an asset or (liability) position, and notional values/payment provisions of our derivative instruments:


		December 31, 2020							December 31, 2019
	Consolidated Balance Sheet Location	Fair Value				Notional Value/ Payment Provision			Fair Value					Notional Value/ Payment Provision
		Derivative Asset		Derivative (Liability)				Derivative Asset			Derivative (Liability)
(in millions of U.S. dollars)
Investment and embedded derivative instruments:
Foreign currency forward contracts	OA / (AP)	$	22	$	(49)	$	2,807		$	11		$	(78)	$	2,579



Options/Futures contracts on notes, bonds, and equities	OA / (AP)	13		(3)		1,749			13			(15)		1,615

Convertible securities (1)	FM AFS / ES	9		—		11			4			—		5

		$	44	$	(52)	$	4,567		$	28		$	(93)	$	4,199
Other derivative instruments:
Futures contracts on equities (2)	OA / (AP)	$	—	$	(17)	$	709		$	—		$	(13)	$	613


Other	OA / (AP)	—		—		16			2			—		63
		$	—	$	(17)	$	725		$	2		$	(13)	$	676
GLB (3)	(AP)	$	—	$	(1,089)	$	1,658		$	—		$	(897)	$	1,510

(1)Includes fair value of embedded derivatives.

(2)Related to GMDB and GLB book of business.

(3)Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.

At December 31, 2020 and 2019, net derivative liabilities of $30 million and $75 million, respectively, included in the table above were subject to a master netting agreement. The remaining derivatives included in the table above were not subject to a master netting agreement.

b) Derivative instrument objectives

(i) Foreign currency exposure management

A foreign currency forward contract (forward) is an agreement between participants to exchange specific currencies at a future date. Chubb uses forwards to minimize the effect of fluctuating foreign currencies as discussed above.

(ii) Duration management and market exposure

Futures

Futures contracts give the holder the right and obligation to participate in market movements, determined by the index or underlying security on which the futures contract is based. Settlement is made daily in cash by an amount equal to the change in value of the futures contract times a multiplier that scales the size of the contract. Exchange-traded futures contracts on money market instruments, notes and bonds are used in fixed maturity portfolios to more efficiently manage duration, as substitutes for ownership of the money market instruments, bonds and notes without significantly increasing the risk in the portfolio. Investments in futures contracts may be made only to the extent that there are assets under management not otherwise committed.

Exchange-traded equity futures contracts are used to limit exposure to a severe equity market decline, which would cause an increase in expected claims and therefore, an increase in future policy benefit reserves for GMDB and an increase in the fair value liability for GLB reinsurance business.

Options

An option contract conveys to the holder the right, but not the obligation, to purchase or sell a specified amount or value of an underlying security at a fixed price. Option contracts are used in our investment portfolio as protection against unexpected shifts in interest rates, which would affect the duration of the fixed maturity portfolio. By using options in the portfolio, the overall interest rate sensitivity of the portfolio can be reduced. Option contracts may also be used as an alternative to futures contracts in the synthetic strategy as described above.

The price of an option is influenced by the underlying security, expected volatility, time to expiration, and supply and demand.

The credit risk associated with the above derivative financial instruments relates to the potential for non-performance by counterparties. Although non-performance is not anticipated, in order to minimize the risk of loss, management monitors the creditworthiness of its counterparties and obtains collateral. The performance of exchange-traded instruments is guaranteed by the exchange on which they trade. For non-exchange-traded instruments, the counterparties are principally banks which must meet certain criteria according to our investment guidelines.

Interest rate swaps

An interest rate swap is a contract between two counterparties in which interest payments are made based on a notional principal amount, which itself is never paid or received. Under the terms of an interest rate swap, one counterparty makes interest payments based on a fixed interest rate and the other counterparty’s payments are based on a floating rate. Interest rate swap contracts are used occasionally in our investment portfolio as protection against unexpected shifts in interest rates, which would affect the fair value of the fixed maturity portfolio. By using interest rate swaps in the portfolio, the overall duration or interest rate sensitivity of the portfolio can be impacted.

Cross-currency swaps

Cross-currency swaps are agreements under which two counterparties exchange interest payments and principal denominated in different currencies at a future date. We use cross-currency swaps to reduce the foreign currency and interest rate risk by converting cash flows back into local currency. We invest in foreign currency denominated investments to improve credit diversification and also to obtain better duration matching to our liabilities that is limited in the local currency market.

Other

Included within Other are derivatives intended to reduce potential losses which may arise from certain exposures in our insurance business. The economic benefit provided by these derivatives is similar to purchased reinsurance. For example, Chubb may enter into crop derivative contracts to protect underwriting results in the event of a significant decline in commodity prices.

(iii) Convertible security investments

A convertible security is a debt instrument or preferred stock that can be converted into a predetermined amount of the issuer’s equity. The convertible option is an embedded derivative within the host instruments which are classified in the investment portfolio as either available for sale or as an equity security. Chubb purchases convertible securities for their total return and not specifically for the conversion feature.

(iv) TBA

By acquiring TBAs, we make a commitment to purchase a future issuance of mortgage-backed securities. For the period between purchase of the TBAs and issuance of the underlying security, we account for our position as a derivative in the Consolidated Financial Statements. Chubb purchases TBAs both for their total return and for the flexibility they provide related to our mortgage-backed security strategy.

(v) GLB

Under the GLB program, as the assuming entity, Chubb is obligated to provide coverage until the expiration or maturity of the underlying deferred annuity contracts or the expiry of the reinsurance treaty. The GLB is accounted for as a derivative and is recorded at fair value. Fair value represents management’s estimate of an exit price and thus, includes a risk margin. We may recognize a realized loss for other changes in fair value due to adverse changes in the capital markets (e.g., declining interest rates and/or declining U.S. and/or international equity markets) and changes in actual or estimated future policyholder behavior (e.g., increased annuitization or decreased lapse rates) although we expect the business to be profitable.

To mitigate adverse changes in the capital markets, we maintain positions in exchange-traded equity futures contracts, as noted under section "(ii) Futures" above. These futures increase in fair value when the S&P 500 index decreases (and decrease in fair

value when the S&P 500 index increases). The net impact of gains or losses related to changes in fair value of the GLB liability and the exchange-traded equity futures are included in Net realized gains (losses).

c) Securities lending and secured borrowings

Chubb participates in a securities lending program operated by a third-party banking institution whereby certain assets are loaned to qualified borrowers and from which we earn an incremental return. The securities lending collateral can only be drawn down by Chubb in the event that the institution borrowing the securities is in default under the lending agreement. An indemnification agreement with the lending agent protects us in the event a borrower becomes insolvent or fails to return any of the securities on loan. The collateral is recorded in Securities lending collateral and the liability is recorded in Securities lending payable in the Consolidated balance sheets. The following table presents the carrying value of collateral held under securities lending agreements by investment category and remaining contractual maturity of the underlying agreements:


	Remaining contractual maturity
	December 31, 2020		December 31, 2019
(in millions of U.S. dollars)	Overnight and Continuous
Collateral held under securities lending agreements:
Cash	$	551	$	346
U.S. Treasury / Agency	148		6
Non-U.S.	1,032		595
Corporate and asset-backed securities	30		5
Mortgage-backed securities	4		18

Equity securities	79		24

	$	1,844	$	994
Gross amount of recognized liability for securities lending payable	$	1,844	$	994

At December 31, 2020 and 2019, our repurchase agreement obligations of $1,405 million and $1,416 million, respectively, were fully collateralized. In contrast to securities lending programs, the use of cash received is not restricted for the repurchase obligations. The fair value of the underlying securities sold remains in Fixed maturities available for sale, and the repurchase agreement obligation is recorded in Repurchase agreements in the Consolidated balance sheets.

The following table presents the carrying value of collateral pledged under repurchase agreements by investment category and remaining contractual maturity of the underlying agreements:


	Remaining contractual maturity
	December 31, 2020									December 31, 2019
	30-90 Days		Greater than 90 Days					Up to 30 Days		30-90 Days		Greater than 90 Days		Total
(in millions of U.S. dollars)					Total
Collateral pledged under repurchase agreements:
Cash	$	—	$	4		$	4	$	2	$	—	$	—	$	2
U.S. Treasury / Agency	—		106			106		107		—		—		107


Mortgage-backed securities	481		871			1,352		399		476		480		1,355


	$	481	$	981		$	1,462	$	508	$	476	$	480	$	1,464
Gross amount of recognized liabilities for repurchase agreements						$	1,405							$	1,416
Difference (1)						$	57							$	48

(1)Per the repurchase agreements, the amount of collateral posted is required to exceed the amount of gross liability.

Potential risks exist in our secured borrowing transactions due to market conditions and counterparty exposure. With collateral that we pledge, there is a risk that the collateral may not be returned at the expiration of the agreement. If the counterparty fails to return the collateral, Chubb will have free use of the borrowed funds until our collateral is returned. In addition, we may encounter the risk that Chubb may not be able to renew outstanding borrowings with a new term or with an existing counterparty due to market conditions including a decrease in demand as well as more restrictive terms from banks due to

increased regulatory and capital constraints. Should this condition occur, Chubb may seek alternative borrowing sources or reduce borrowings. Additionally, increased margins and collateral requirements due to market conditions would increase our restricted assets as we are required to provide additional collateral to support the transaction.

The following table presents net realized gains (losses) related to derivative instrument activity in the Consolidated statements of operations:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Investment and embedded derivative instruments:
Foreign currency forward contracts	$	65	$	(79)	$	3
Interest rate swaps	—		(270)		(115)
All other futures contracts, options, and equities	16		(88)		39
Convertible securities (1)	—		2		(2)
Total investment and embedded derivative instruments	$	81	$	(435)	$	(75)
GLB and other derivative instruments:
GLB	$	(202)	$	(4)	$	(248)
Futures contracts on equities (2)	(108)		(138)		(4)

Other	1		(8)		(3)
Total GLB and other derivative instruments	$	(309)	$	(150)	$	(255)
	$	(228)	$	(585)	$	(330)

(1)Includes embedded derivatives.

(2)Related to GMDB and GLB book of business.

d) Concentrations of credit risk

Our investment portfolio is managed following prudent standards of diversification. Specific provisions limit the allowable holdings of a single issue and issuer. We believe that there are no significant concentrations of credit risk associated with our investments. Our three largest corporate exposures by issuer at December 31, 2020, were Wells Fargo & Co., Bank of America Corp, and JP Morgan Chase & Co. Our largest exposure by industry at December 31, 2020 was financial services.

We market our insurance and reinsurance worldwide primarily through insurance and reinsurance brokers. We assume a degree of credit risk associated with brokers with whom we transact business. For the years ended December 31, 2020, 2019 and 2018, approximately 12 percent, 12 percent, and 10 percent, respectively, of our gross premiums written was generated from or placed by Marsh & McLennan Companies, Inc. This entity is a large, well-established company, and there are no indications that it is financially troubled at December 31, 2020. No other broker or one insured accounted for more than 10 percent of our gross premiums written for these years.

e) Fixed maturities

At December 31, 2020, we have commitments to purchase fixed income securities of $605 million over the next several years.

f) Other investments

At December 31, 2020, included in Other investments in the Consolidated balance sheet are investments in limited partnerships and partially-owned investment companies with a carrying value of $6.5 billion. In connection with these investments, we have commitments that may require funding of up to $3.2 billion over the next several years. At December 31, 2019, these investments had a carrying value of $4.7 billion with a commitment that may require funding of up to $3.3 billion.

g) Letters of credit

We have access to capital markets and to credit facilities with letter of credit capacity of $4.0 billion with a sub-limit of $1.9 billion for revolving credit. Our existing credit facilities have remaining terms expiring through October 2022. At December 31, 2020, our LOC usage was $1.7 billion.

h) Legal proceedings

Our insurance subsidiaries are subject to claims litigation involving disputed interpretations of policy coverages and, in some jurisdictions, direct actions by allegedly-injured persons seeking damages from policyholders. These lawsuits, involving claims on policies issued by our subsidiaries which are typical to the insurance industry in general and in the normal course of

business, are considered in our loss and loss expense reserves. In addition to claims litigation, we are subject to lawsuits and regulatory actions in the normal course of business that do not arise from or directly relate to claims on insurance policies. This category of business litigation typically involves, among other things, allegations of underwriting errors or misconduct, employment claims, regulatory activity, or disputes arising from our business ventures. In the opinion of management, our ultimate liability for these matters could be, but we believe is not likely to be, material to our consolidated financial condition and results of operations.

i) Lease commitments

At December 31, 2020 and 2019, the right-of-use asset was $473 million and $551 million, respectively, recorded within Other assets on the Consolidated balance sheets, and the lease liability was $517 million and $603 million, respectively, which was recorded within Accounts payable, accrued expenses, and other liabilities on the Consolidated balance sheets. These leases consist principally of real estate operating leases that are amortized on a straight-line basis over the term of the lease, which expire at various dates. As of December 31, 2020, the weighted average remaining lease term and weighted average discount rate for the operating leases was 4.9 years and 2.6 percent, respectively. Rent expense was $152 million, $171 million, and $169 million for the years ended December 31, 2020, 2019, and 2018, respectively.

Future minimum lease payments under the operating leases are expected to be as follows:


For the years ending December 31
(in millions of U.S. dollars)
Undiscounted cash flows:
2021	$	150
2022	123
2023	96
2024	68
2025	38
Thereafter	75
Total undiscounted lease payments	$	550
Less: Present value adjustment	33
Net lease liabilities reported as of December 31, 2020	$	517

Shareholders' equity note

12 Months Ended

Dec. 31, 2020

Stockholders' Equity Note [Abstract]

Shareholders' equity

Shareholders’ equity

a) Common Shares

All of Chubb’s Common Shares are authorized under Swiss corporate law. Though the par value of Common Shares is stated in Swiss francs, Chubb continues to use U.S. dollars as its reporting currency for preparing the Consolidated Financial Statements. Under Swiss corporate law, we are generally prohibited from issuing Common Shares below their par value. If there were a need to raise common equity at a time when the trading price of Chubb's Common Shares is below par value, we would need in advance to obtain shareholder approval to decrease the par value of the Common Shares.

Dividend approval

At our May 2019 and 2018 annual general meetings, our shareholders approved annual dividends for the following year of up to $3.00 per share and $2.92 per share, respectively, which were paid in four quarterly installments of $0.75 per share and $0.73 per share, respectively, at dates determined by the Board of Directors (Board) after the annual general meeting by way of a distribution from capital contribution reserves, transferred to free reserves for payment.

At our May 2020 annual general meeting, our shareholders approved an annual dividend for the following year of up to $3.12 per share, expected to be paid in four quarterly installments of $0.78 per share after the annual general meeting by way of distribution from capital contribution reserves, transferred to free reserves for payment. The Board will determine the record and payment dates at which the annual dividend may be paid until the date of the 2021 annual general meeting, and is authorized to abstain from distributing a dividend at its discretion. The first three quarterly installments each of $0.78 per share, have been distributed by the Board as expected.

Dividend distributions

Under Swiss corporate law, dividends must be stated in Swiss francs though dividend payments are made by Chubb in U.S. dollars. We issue dividends without subjecting them to withholding tax by way of distributions from capital contribution reserves and payment out of free reserves.

The following table presents dividend distributions per Common Share in Swiss francs (CHF) and U.S. dollars (USD):


	Year Ended December 31
		2020			2019			2018
	CHF	USD		CHF	USD		CHF	USD
Total dividend distributions per common share	2.89	$	3.09	2.94	$	2.98	2.84	$	2.90

b) Shares issued, outstanding, authorized, and conditional


	Year Ended December 31
	2020	2019	2018
Common Shares authorized and issued, beginning of year	479,783,864	479,783,864	479,783,864
Cancellation of treasury shares	(2,178,600)	—	—
Common Shares authorized and issued, end of year	477,605,264	479,783,864	479,783,864
Common Shares in treasury, beginning of year (at cost)	(27,812,297)	(20,580,486)	(15,950,685)
Net shares issued under employee share-based compensation plans	2,345,208	3,210,427	3,089,234
Shares repurchased	(3,584,150)	(10,442,238)	(7,719,035)
Cancellation of treasury shares	2,178,600	—	—
Common Shares in treasury, end of year (at cost)	(26,872,639)	(27,812,297)	(20,580,486)
Common Shares outstanding, end of year	450,732,625	451,971,567	459,203,378

Increases in Common Shares in treasury are due to open market repurchases of Common Shares and the surrender of Common Shares to satisfy tax withholding obligations in connection with the vesting of restricted stock and the forfeiture of unvested restricted stock. Decreases in Common Shares in treasury are principally due to grants of restricted stock, exercises of stock options, purchases under the Employee Stock Purchase Plan (ESPP), and share cancellations. At our May 2020 annual general meeting, our shareholders approved the cancellation of 2,178,600 shares purchased under our share repurchase program during the period beginning September 23, 2019 and ending December 31, 2019. The capital reduction by cancellation of shares was subject to publication requirements and a two-month waiting period in accordance with Swiss law and became effective August 3, 2020.

Authorized share capital for general purposes under Swiss law

In accordance with Swiss law, the Board has shareholder-approved authority as set forth in the Articles of Association to increase Chubb's share capital from time to time until May 20, 2022, by the issuance for general purposes of up to 200,000,000 fully paid up Common Shares, with a par value equal to the par value of Chubb's Common Shares as set forth in the Articles of Association at the time of any such issuance. Any such increases would be subject to Swiss rules and procedure.

Conditional share capital for bonds and similar debt instruments

Chubb's share capital may be increased through the issuance of a maximum of 33,000,000 fully paid up Common Shares (with a par value of CHF 24.15 as of December 31, 2020) through the exercise of conversion and/or option or warrant rights granted in connection with bonds, notes, or similar instruments, issued or to be issued by Chubb, including convertible debt instruments.

Conditional share capital for employee benefit plans

Chubb's share capital may be increased through the issuance of a maximum of 25,410,929 fully paid up Common Shares (with a par value of CHF 24.15 as of December 31, 2020) in connection with the exercise of option rights granted to any employee of Chubb, director or other person providing services to Chubb.

c) Chubb Limited securities repurchases

From time to time, we repurchase shares as part of our capital management program and to partially offset potential dilution from the exercise of stock options and the granting of restricted stock under share-based compensation plans. The Board has authorized share repurchase programs as follows:

•$1.0 billion of Chubb Common Shares from January 1, 2018 through December 31, 2018

•$1.5 billion of Chubb Common Shares from December 1, 2018 through December 31, 2019

•$1.5 billion of Chubb Common Shares from November 21, 2019 through December 31, 2020

•$1.5 billion of Chubb Common Shares from November 19, 2020 through December 31, 2021

Subsequently, in February 2021, the Board approved an increase to the November 2020 share repurchase program of $1.0 billion to a total of $2.5 billion, effective through December 31, 2021.

Share repurchases may be in the open market, in privately negotiated transactions, block trades, accelerated repurchases and through option or other forward transactions.

The following table presents repurchases of Chubb's Common Shares conducted in a series of open market transactions under the Board authorizations:


	Year Ended December 31						January 1, 2021 through
(in millions of U.S. dollars, except share data)	2020		2019		2018		February 24, 2021
Number of shares repurchased	3,584,150		10,442,238		7,719,035		1,971,000
Cost of shares repurchased (1)	$	516	$	1,531	$	1,021	$	327

(1)On April 22, 2020, we suspended share repurchases, given the economic environment and to preserve capital for both risk and opportunity. Subsequently, we announced and then resumed share repurchases on October 29, 2020.

d) General restrictions

The holders of the Common Shares are entitled to receive dividends as approved by the shareholders. Holders of Common Shares are allowed one vote per share provided that, if the controlled shares of any shareholder constitute ten percent or more of the outstanding Common Shares of Chubb, only a fraction of the vote will be allowed so as not to exceed ten percent in aggregate. Entry of acquirers of Common Shares as shareholders with voting rights in the share register may be refused if it would confer voting rights with respect to ten percent or more of the registered share capital recorded in the commercial register.

Share-based compensation

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Share-based compensation

Chubb has share-based compensation plans which currently provide the Board the ability to grant awards of stock options, restricted stock, and restricted stock units to its employees and members of the Board.

In May 2016, our shareholders approved the Chubb Limited 2016 Long-Term Incentive Plan (the 2016 LTIP), which replaced both the ACE Limited 2004 LTIP (the 2004 LTIP) and The Chubb Corporation Long-Term Incentive Plan (2014). The 2016 LTIP is substantially similar to the 2004 LTIP in its operation and the types of awards that may be granted. Under the 2016 LTIP, Common Shares of Chubb were authorized to be issued pursuant to awards made as stock options, stock appreciation rights, performance shares, performance units, restricted stock, and restricted stock units.

Chubb principally issues restricted stock grants and stock options on a graded vesting schedule, with equal percentages of the award subject to vesting over a number of years (typically three or four). Chubb recognizes compensation cost for vesting of restricted stock and stock option grants with only service conditions on a straight-line basis over the requisite service period for each separately vesting portion of the award as if the award were, in-substance, multiple awards. We incorporate an estimate of future forfeitures in determining compensation cost for both grants of restricted stock and stock options.

In addition, Chubb grants performance-based restricted stock to certain executives that vest based on certain performance criteria as compared to a defined group of peer companies. Performance-based stock awards comprise target awards and premium awards that cliff vest at the end of a 3-year performance period based on both our tangible book value (shareholders' equity less goodwill and intangible assets, net of tax) per share growth and P&C combined ratio compared to our peer group. Premium awards are subject to an additional vesting provision based on total shareholder return (TSR) compared to our peer

group. Shares representing target awards and premium awards are issued when the awards are approved and are subject to forfeiture if applicable performance criteria are not met at the end of the 3-year performance period. Prior to January 2017, performance-based restricted stock awards had a 4-year vesting period with the potential to vest as to a portion each year, and excluded the P&C combined ratio and TSR additional vesting criteria.

Under the 2016 LTIP, 19,500,000 Common Shares are authorized to be issued. This is in addition to any shares that have not been delivered pursuant to the 2004 LTIP and remain available for grant pursuant to the 2004 LTIP and includes any shares covered by awards granted under the 2004 LTIP that have forfeited, expired or canceled after the effective date of the 2016 LTIP. At December 31, 2020, a total of 7,576,239 shares remain available for future issuance under the 2016 LTIP, which includes shares canceled or forfeited from the 2004 LTIP, in addition to common shares that were previously registered and authorized to be issued.

Under the Employee Stock Purchase Plan (ESPP), 6,500,000 shares are authorized to be issued. At December 31, 2020, a total of 1,402,017 shares remain available for issuance under the ESPP.

Chubb generally issues Common Shares for the exercise of stock options, restricted stock, and purchases under the ESPP from Common Shares in treasury.

The following table presents pre-tax and after-tax share-based compensation expense:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Stock options and shares issued under ESPP:
Pre-tax	$	45	$	42	$	50
After-tax (1)	$	38	$	39	$	40
Restricted stock:
Pre-tax	$	210	$	224	$	235
After-tax (1)	$	164	$	180	$	178

(1)The windfall tax benefit recorded to Income tax expense in the Consolidated statement of operations was $10 million, $12 million, and $19 million for the years ended December 31, 2020, 2019, and 2018, respectively.

Unrecognized compensation expense related to the unvested portion of Chubb's employee share-based awards of restricted stock, restricted stock units, and stock options was $199 million at December 31, 2020 and is expected to be recognized over a weighted-average period of approximately 1 year.

Stock options

Both incentive and non-qualified stock options are principally granted at an option price per share equal to the grant date fair value of Chubb's Common Shares. Stock options are generally granted with a 3-year vesting period and a 10-year term. Stock options vest in equal annual installments over the respective vesting period, which is also the requisite service period.

Chubb's 2020 share-based compensation expense includes a portion of the cost related to the 2017 through 2020 stock option grants. Stock option fair value was estimated on the grant date using the Black-Scholes option-pricing model that uses the weighted-average assumptions noted below:


	Year Ended December 31
	2020		2019		2018
Dividend yield	2.1	%	2.2	%	2.0	%
Expected volatility	18.0	%	16.0	%	23.2	%
Risk-free interest rate	1.2	%	2.6	%	2.7	%
Expected life	5.7 years		5.7 years		5.7 years

The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant. The expected life (estimated period of time from grant to exercise date) is estimated using the historical exercise behavior of employees. For years 2020 and 2019, expected volatility is calculated as a blend of (a) historical volatility based on daily closing prices over a period equal to

the expected life assumption and (b) implied volatility derived from Chubb's publicly traded options. For year 2018, expected volatility was calculated as a blend of (a) historical volatility based on daily closing prices over a period equal to the expected life assumption, (b) long-term historical volatility based on daily closing prices over the period from Chubb's initial public trading date through the most recent quarter, and (c) implied volatility derived from Chubb's publicly traded options.

The following table presents a roll-forward of Chubb's stock options:


(Intrinsic Value in millions of U.S. dollars)	Number of Options	Weighted-Average Exercise Price		Weighted-Average Fair Value		Total Intrinsic Value
Options outstanding, December 31, 2017	10,433,316	$	99.20
Granted	1,842,690	$	143.07	$	29.71
Exercised	(1,065,384)	$	73.57			$	71
Forfeited and expired	(202,900)	$	133.92
Options outstanding, December 31, 2018	11,007,722	$	108.25
Granted	2,073,940	$	133.90	$	18.76
Exercised	(1,944,604)	$	84.13			$	122
Forfeited and expired	(251,801)	$	136.87
Options outstanding, December 31, 2019	10,885,257	$	116.79
Granted	1,958,279	$	150.10	$	19.89
Exercised	(1,158,633)	$	86.90			$	76
Forfeited and expired	(206,720)	$	138.77
Options outstanding, December 31, 2020	11,478,183	$	125.09			$	331
Options exercisable, December 31, 2020	7,792,343	$	116.35			$	293

The weighted-average remaining contractual term was 6.0 years for stock options outstanding and 4.8 years for stock options exercisable at December 31, 2020. Cash received from the exercise of stock options for the year ended December 31, 2020 was $100 million.

Restricted stock and restricted stock units

Grants of restricted stock and restricted stock units awarded under both the 2004 LTIP and 2016 LTIP typically have a 4-year vesting period, subject to vesting as to one-quarter of the award each anniversary of grant. Restricted stock and restricted stock units are granted at market close price on the day of grant. Each restricted stock unit represents our obligation to deliver to the holder one Common Share upon vesting.

Chubb also grants restricted stock awards to non-management directors which vest at the following year's annual general meeting.

Chubb's 2020 share-based compensation expense includes a portion of the cost related to the restricted stock granted in the years 2016 through 2020.

The following table presents a roll-forward of our restricted stock awards. Included in the roll-forward below are 27,679 restricted stock awards, 19,019 restricted stock awards, and 20,784 restricted stock awards that were granted to non-management directors during the years ended December 31, 2020, 2019, and 2018, respectively:


	Service-based Restricted Stock Awards and Restricted Stock Units			Performance-based Restricted Stock Awards and Restricted Stock Units
	Number of Shares	Weighted-Average Grant-Date Fair Value		Number of Shares	Weighted-Average Grant-Date Fair Value
Unvested restricted stock, December 31, 2017	4,709,442	$	121.16	975,497	$	118.28
Granted	1,326,979	$	142.76	180,065	$	143.07
Vested	(2,545,090)	$	114.83	(244,332)	$	103.03
Forfeited	(196,482)	$	131.06	—	$	—
Unvested restricted stock, December 31, 2018	3,294,849	$	134.17	911,230	$	127.27
Granted	1,492,900	$	134.38	212,059	$	133.90
Vested	(1,292,864)	$	129.18	(196,640)	$	115.62
Forfeited	(200,875)	$	135.98	(50,437)	$	132.36
Unvested restricted stock, December 31, 2019	3,294,010	$	136.20	876,212	$	131.16
Granted	1,425,667	$	148.56	186,291	$	151.14
Vested	(1,304,308)	$	134.02	(490,185)	$	125.66
Forfeited	(152,074)	$	140.72	—	$	—
Unvested restricted stock, December 31, 2020	3,263,295	$	142.32	572,318	$	142.38

Prior to 2009, legacy ACE granted restricted stock units with a 1-year vesting period to non-management directors. Delivery of Common Shares on account of these restricted stock units to non-management directors is deferred until after the date of the non-management directors' termination from the Board. Legacy Chubb Corp historically allowed directors and certain key employees of Chubb Corp and its subsidiaries to defer a portion of their compensation earned with respect to services performed in the form of deferred stock units. In addition, legacy Chubb Corp provided supplemental retirement benefits for certain employees through its Defined Contribution Excess Benefit Plan in the form of deferred shares of stock. The minimum vesting period under these legacy Chubb Corp deferred plans was 1-year and the maximum was 3-years. Employees and directors had the option to elect to receive their awards at a future specified date or upon their termination of service with Chubb. At December 31, 2020, there were 166,624 deferred restricted stock units.

ESPP

The ESPP gives participating employees the right to purchase Common Shares through payroll deductions during consecutive subscription periods at a purchase price of 85 percent of the fair value of a Common Share on the exercise date (Purchase Price). Annual purchases by participants are limited to the number of whole shares that can be purchased by an amount equal to ten percent of the participant's compensation or $25,000, whichever is less. The ESPP has two six-month subscription periods each year, the first of which runs between January 1 and June 30 and the second of which runs between July 1 and December 31. The amounts collected from participants during a subscription period are used on the exercise date to purchase full shares of Common Shares. An exercise date is generally the last trading day of a subscription period. The number of shares purchased is equal to the total amount, at the exercise date, collected from the participants through payroll deductions for that subscription period, divided by the Purchase Price, rounded down to the next full share. Participants may withdraw from an offering before the exercise date and obtain a refund of amounts withheld through payroll deductions. Pursuant to the provisions of the ESPP, during the years ended December 31, 2020, 2019, and 2018, employees paid $45 million, $41 million, and $37 million to purchase 383,751 shares, 321,800 shares, and 347,116 shares, respectively.

Postretirement benefits

12 Months Ended

Dec. 31, 2020

Retirement Benefits [Abstract]

Postretirement benefits

Chubb provides postretirement benefits to eligible employees and their dependents through various defined contribution plans sponsored by Chubb. In addition, for certain employees, Chubb sponsors other postretirement benefit plans, and prior to 2020, Chubb sponsored defined benefit pension plans.

Defined contribution plans (including 401(k))

Under these plans, employees' contributions may be supplemented by Chubb matching contributions based on the level of employee contribution. These contributions are invested at the election of each employee in one or more of several investment portfolios offered by a third-party investment advisor. Expenses for these plans totaled $211 million, $171 million, and $171 million for the years ended December 31, 2020, 2019, and 2018, respectively.

Defined benefit pension plans

We maintain non-contributory defined benefit pension plans that cover certain employees located in the U.S., U.K., Canada, and various other statutorily required countries. We account for pension benefits using the accrual method. Benefits under these plans are based on employees' years of service and compensation during final years of service. All underlying plans are subject to periodic actuarial valuations by qualified actuarial firms using actuarial models to calculate the expense and liability for each plan. We use December 31 as the measurement date for our defined benefit pension plans.

Under the Chubb Corp plans, prior to 2001, benefits were generally based on an employee’s years of service and average compensation during the last five years of employment. Effective January 1, 2001, the formula for providing pension benefits was changed from the final average pay formula to a cash balance formula. Under the cash balance formula, a notional account is established for each employee, which is credited semi-annually with an amount equal to a percentage of eligible compensation based on age and years of service plus interest based on the account balance. Chubb Corp employees hired prior to 2001 will generally be eligible to receive vested benefits based on the higher of the final average pay or cash balance formulas.

Other postretirement benefit plans

Our assumption of Chubb Corp's other postretirement benefit plans, principally healthcare and life insurance, covers retired employees, their beneficiaries, and covered dependents. Healthcare coverage is contributory. Retiree contributions vary based upon the retiree’s age, type of coverage, and years of service requirements. Life insurance coverage is non-contributory. Chubb funds a portion of the healthcare benefits obligation where such funding can be accomplished on a tax-effective basis. Benefits are paid as covered expenses are incurred.

Amendments to U.S. qualified and excess pension plans and U.S. retiree healthcare plan

On October 31, 2016, we harmonized and amended several of our U.S. retirement programs to create a unified retirement savings program. In 2020, we transitioned from a traditional defined benefit pension program that had been in effect for certain employees to a defined contribution program. Additionally, after 2025, we plan to eliminate a subsidized U.S. retiree healthcare and life insurance plan that had been in place for certain employees. Both amendments required a remeasurement of the plan assets and benefit obligations with updated assumptions, including discount rates and the expected return on assets. The amendment of the retiree healthcare plan resulted in a reduction in the obligation of $383 million, of which $410 million will be amortized as a reduction to expense through 2021 as it relates to benefits already accrued. For the years ended December 31, 2020, 2019, and 2018, $79 million, $79 million, and $80 million, respectively, were amortized as a reduction to expense. At December 31, 2020, the remaining curtailment benefit balance was $26 million which will be amortized as a reduction to expense through June 2021.

Obligations and funded status

The funded status of the pension and other postretirement benefit plans as well as the amounts recognized in Accumulated other comprehensive income at December 31, 2020 and 2019 was as follows:


	Pension Benefit Plans								Other Postretirement Benefit Plans
	2020				2019				2020		2019
	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
Benefit obligation, beginning of year	$	3,569	$	1,042	$	3,092	$	942	$	103	$	113

Service cost	—		4		49		11		1		—
Interest cost	99		22		118		27		2		4
Actuarial loss (gain)	441		135		443		124		1		3
Benefits paid	(127)		(31)		(121)		(39)		(20)		(17)

Curtailments	—		(2)		—		(4)		—		—
Settlements	(15)		—		(12)		(61)		—		—
Foreign currency revaluation and other	—		29		—		42		(1)		—
Benefit obligation, end of year	$	3,967	$	1,199	$	3,569	$	1,042	$	86	$	103
Plan assets at fair value, beginning of year	$	3,301	$	1,141	$	2,784	$	1,008	$	152	$	143

Actual return on plan assets	563		126		636		169		6		9
Employer contributions	17		19		14		16		1		—
Benefits paid	(127)		(31)		(121)		(39)		(39)		—
Settlements	(15)		—		(12)		(61)		—		—
Foreign currency revaluation and other	—		29		—		48		—		—
Plan assets at fair value, end of year	$	3,739	$	1,284	$	3,301	$	1,141	$	120	$	152
Funded status at end of year	$	(228)	$	85	$	(268)	$	99	$	34	$	49
Amounts recognized in Accumulated other comprehensive income, not yet recognized in net periodic cost (benefit):
Net actuarial loss (gain)	$	78	$	163	$	(21)	$	110	$	(5)	$	(3)
Prior service cost (benefit)	—		9		—		10		(31)		(114)
Total	$	78	$	172	$	(21)	$	120	$	(36)	$	(117)

For the U.S. pension plans, the $441 million and $443 million actuarial loss experienced in 2020 and 2019, respectively, was principally driven by the decrease in the discount rate from the respective prior year.

The accumulated benefit obligation for the pension benefit plans was $5.1 billion and $4.6 billion at December 31, 2020 and 2019, respectively. The accumulated benefit obligation is the present value of pension benefits earned as of the measurement date based on employee service and compensation prior to that date. It differs from the pension (projected) benefit obligation in the table above in that the accumulated benefit obligation includes no assumptions regarding future compensation levels.

The net components of the funded status of the pension and other postretirement benefit plans are included in Accounts payable, accrued expenses, and other liabilities in the Consolidated balance sheets.

Chubb’s funding policy is to contribute amounts that meet regulatory requirements plus additional amounts determined based on actuarial valuations, market conditions and other factors. All benefit plans satisfy minimum funding requirements of the Employee Retirement Income Security Act of 1974 (ERISA).

The following table provides information on pension plans where the benefit obligation is in excess of plan assets at December 31, 2020 and 2019:


	2020				2019
	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
Plans with projected benefit obligation in excess of plan assets:
Projected benefit obligation	$	3,967	$	629	$	3,569	$	236
Fair value of plan assets	3,739		568		3,301		175
Net funded status	$	(228)	$	(61)	$	(268)	$	(61)
Plans with accumulated benefit obligation in excess of plan assets:
Accumulated benefit obligation	$	3,967	$	593	$	3,569	$	173
Fair value of plan assets	$	3,739	$	565	$	3,301	$	140

For other postretirement benefit plans with an accumulated benefit obligation in excess of plan assets, the accumulated benefit obligation was $23 million and $25 million at December 31, 2020 and 2019, respectively. These plans have no plan assets.

At December 31, 2020, we estimate that we will contribute $20 million to the pension plans and $1 million to the other postretirement benefits plan in 2021. The estimate is subject to change due to contribution decisions that are affected by various factors including our liquidity, market performance and management discretion.

At December 31, 2020, our estimated expected future benefit payments are as follows:


	Pension Benefit Plans				Other Postretirement Benefit Plans
For the years ending December 31	U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
2021	$	159	$	30	$	19
2022	166		28		20
2023	171		30		16
2024	175		32		12
2025	180		32		7
2026-2030	947		185		5

The weighted-average assumptions used to determine the projected benefit obligation were as follows:


	Pension Benefit Plans
	U.S. Plans		Non-U.S. Plans		Other Postretirement Benefit Plans

December 31, 2020
Discount rate	2.32	%	1.80	%	1.36	%
Rate of compensation increase (1)	N/A		3.24	%	N/A
Interest crediting rate	4.10	%
December 31, 2019
Discount rate	3.20	%	2.39	%	2.70	%
Rate of compensation increase (1)	N/A		3.26	%	N/A
Interest crediting rate	4.10	%

(1) For the U.S. Pension Plans, benefit accruals were frozen as of December 31, 2019.

The projected benefit cash flows were discounted using the corresponding spot rates derived from a yield curve, which resulted in a single discount rate that would produce the same liability at the respective measurement dates. The same process was applied to service cost cash flows to determine the discount rate associated with the service cost. In general, the discount rates for the non-U.S. plans were developed using a similar methodology by using country-specific yield curves.

The components of net pension and other postretirement benefit costs reflected in Net income and other changes in plan assets and benefit obligations recognized in other comprehensive income were as follows:


	Pension Benefit Plans												Other Postretirement Benefit Plans
	U.S. Plans						Non-U.S. Plans
Year Ended December 31	2020		2019		2018		2020		2019		2018		2020		2019		2018
(in millions of U.S. dollars)
Costs reflected in Net income:
Service cost	$	—	$	49	$	57	$	4	$	11	$	12	$	1	$	—	$	1
Non-service cost:
Interest cost	99		118		105		22		27		27		2		4		3
Expected return on plan assets	(224)		(189)		(212)		(41)		(45)		(50)		(5)		(4)		(5)
Amortization of net actuarial loss	—		—		—		2		3		1		—		—		—
Amortization of prior service cost	—		—		—		—		—		—		(83)		(84)		(85)
Curtailments	—		—		—		(1)		(1)		—		—		—		(2)
Settlements	3		2		2		—		1		3		—		—		—
Total non-service benefit	(122)		(69)		(105)		(18)		(15)		(19)		(86)		(84)		(89)
Net periodic benefit	$	(122)	$	(20)	$	(48)	$	(14)	$	(4)	$	(7)	$	(85)	$	(84)	$	(88)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net actuarial loss (gain)	$	102	$	(4)	$	214	$	56	$	6	$	34	$	(2)	$	(2)	$	(11)
Prior service cost (benefit)	—		—		—		—		1		3		—		—		—
Amortization of net actuarial loss	—		—		—		(2)		(3)		(1)		—		—		(1)
Amortization of prior service cost	—		—		—		(1)		—		—		83		84		85
Curtailments	—		—		—		(1)		(3)		—		—		—		3
Settlements	(3)		(2)		(2)		—		(1)		(3)		—		—		—
Total decrease (increase) in other comprehensive income	$	99	$	(6)	$	212	$	52	$	—	$	33	$	81	$	82	$	76

The line items in which the service and non-service cost components of net periodic (benefit) cost are included in the Consolidated statements of operations were as follows:


	Pension Benefit Plans						Other Postretirement Benefit Plans
Year Ended December 31	2020		2019		2018		2020		2019		2018
(in millions of U.S. dollars)
Service cost:
Losses and loss expenses	$	—	$	6	$	7	$	—	$	—	$	—
Administrative expenses	4		54		62		1		—		1
Total service cost	4		60		69		1		—		1
Non-service cost:
Losses and loss expenses	(12)		(7)		(10)		(9)		(8)		(9)
Administrative expenses	(128)		(77)		(114)		(77)		(76)		(80)
Total non-service benefit	(140)		(84)		(124)		(86)		(84)		(89)
Net periodic benefit	$	(136)	$	(24)	$	(55)	$	(85)	$	(84)	$	(88)

The weighted-average assumptions used to determine the net periodic pension and other postretirement benefit costs were as follows:


	Pension Benefit Plans
	U.S. Plans		Non-U.S. Plans		Other Postretirement Benefit Plans
Year Ended December 31
2020
Discount rate in effect for determining service cost	N/A		6.04	%	3.00	%
Discount rate in effect for determining interest cost	2.85	%	2.24	%	2.64	%
Rate of compensation increase	N/A		3.26	%	N/A
Expected long-term rate of return on plan assets	7.00	%	3.83	%	3.00	%
Interest crediting rate	4.10	%	N/A		N/A
2019
Discount rate in effect for determining service cost	4.23	%	4.48	%	4.04	%
Discount rate in effect for determining interest cost	3.94	%	2.88	%	3.69	%
Rate of compensation increase	4.00	%	3.37	%	N/A
Expected long-term rate of return on plan assets	7.00	%	4.40	%	3.00	%
Interest crediting rate	4.10	%	N/A		N/A
2018
Discount rate in effect for determining service cost	3.62	%	3.97	%	2.84	%
Discount rate in effect for determining interest cost	3.27	%	2.55	%	2.62	%
Rate of compensation increase	4.00	%	3.46	%	N/A
Expected long-term rate of return on plan assets	7.00	%	4.32	%	2.59	%
Interest crediting rate	4.10	%	N/A		N/A

The weighted-average healthcare cost trend rate assumptions used to measure the expected cost of healthcare benefits were as follows:


	U.S. Plans						Non-U.S. Plans
	2020		2019		2018		2020		2019		2018
Healthcare cost trend rate	5.96	%	6.32	%	6.68	%	5.04	%	5.24	%	6.29	%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50	%	4.50	%	4.50	%	4.00	%	4.00	%	4.50	%
Year that the rate reaches the ultimate trend rate	2038		2038		2038		2040		2040		2029

Plan Assets

The long term objective of the pension plan is to provide sufficient funding to cover expected benefit obligations, while assuming a prudent level of portfolio risk. The assets of the pension plan are invested, either directly or through pooled funds, in a diversified portfolio of predominately equity securities and fixed maturities. We seek to obtain a rate of return that over time equals or exceeds the returns of the broad markets in which the plan assets are invested. The target allocation of U.S. plan assets is 55 percent to 65 percent invested in equity securities (including certain other investments measured using NAV), with the remainder primarily invested in fixed maturities. The target allocation of non-U.S. plans varies by country, but the plan assets are principally invested in fixed maturities. We rebalance our pension assets to the target allocation as market conditions permit. We determined the expected long term rate of return assumption for each asset class based on an analysis of the historical returns and the expectations for future returns. The expected long term rate of return for the portfolio is a weighted aggregation of the expected returns for each asset class.

In order to minimize risk, the Plan maintains a listing of permissible and prohibited investments. In addition, the Plan has certain concentration limits and investment quality requirements imposed on permissible investments options. Investment risk is measured and monitored on an ongoing basis.

The following tables present the fair values of the pension plan assets, by valuation hierarchy. For additional information on how we classify these assets within the valuation hierarchy, refer to Note 4 to the Consolidated Financial Statements.


December 31, 2020	Pension Benefit Plans
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
U.S. Plans:
Short-term investments	$	59	$	—	$	—	$	59
U.S. Treasury / Agency	250		186		—		436
Non-U.S. and corporate bonds	—		793		—		793
Municipal	—		2		—		2
Equity securities	1,818		—		—		1,818
Total U.S. Plan assets (1)	$	2,127	$	981	$	—	$	3,108
Non-U.S. Plans:
Short-term investments	$	5	$	—	$	—	$	5
Non-U.S. and corporate bonds	—		609		—		609
Equity securities	127		388		—		515
Total Non-U.S. Plan assets (1)	$	132	$	997	$	—	$	1,129

(1)Excluded from the table above are $543 million and $147 million of other investments related to the U.S. Plans and Non-U.S. Plans, respectively, limited partnerships of $74 million and $8 million in U.S. Plans and Non-U.S. Plans, respectively, measured using NAV as a practical expedient, and $14 million in cash related to the U.S. Plans.


December 31, 2019	Pension Benefit Plans
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
U.S. Plans:
Short-term investments	$	18	$	37	$	—	$	55
U.S. Treasury / Agency	466		134		—		600
Non-U.S. and corporate bonds	—		749		—		749
Municipal	—		2		—		2
Equity securities	1,467		—		—		1,467
Total U.S. Plan assets (1)	$	1,951	$	922	$	—	$	2,873
Non-U.S. Plans:
Short-term investments	$	2	$	—	$	—	$	2
Non-U.S. and corporate bonds	—		598		—		598
Equity securities	112		318		—		430
Total Non-U.S. Plan assets (1)	$	114	$	916	$	—	$	1,030

(1)Excluded from the table above are $428 million and $107 million of other investments related to the U.S. Plans and Non-U.S. Plans, respectively, and limited partnerships of $4 million in Non-U.S. Plans, measured using NAV as a practical expedient.

The other postretirement benefit plan had $120 million and $152 million of other investments measured using NAV as a practical expedient at December 31, 2020 and 2019, respectively.

The entire disclosure for retirement benefits.

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Other Income and Expenses [Abstract]

Other (income) expense

12 Months Ended

Dec. 31, 2020

Other (income) expense

Other income and expense


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Equity in net income of partially-owned entities (1)	$	1,019	$	617	$	514
Gains (losses) from fair value changes in separate account assets (2)	58		44		(38)
Federal excise and capital taxes	(22)		(23)		(12)
Other	(61)		(42)		(30)
Total	$	994	$	596	$	434

(1) Equity in net income of partially-owned entities includes $167 million, $74 million, and $43 million attributable to our investments in Huatai (Huatai Group, Huatai P&C, and Huatai Life) for the years ended December 31, 2020, 2019, and 2018, respectively.

(2) Related to gains (losses) from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP.

Other income and expense includes equity in net income of partially-owned entities, which includes our share of net income or loss, both underlying operating income and mark-to-market movement, related to partially-owned investment companies (private equity) and partially-owned insurance companies. Also included in Other income and expense are gains (losses) from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP. The offsetting movement in the separate account liabilities is included in Policy benefits in the Consolidated statements of operations. Certain federal excise and capital taxes incurred as a result of capital management initiatives are included in Other income and expense as these are considered capital transactions and are excluded from underwriting results.

Segment information

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Segment information

Chubb operates through six business segments: North America Commercial P&C Insurance, North America Personal P&C Insurance, North America Agricultural Insurance, Overseas General Insurance, Global Reinsurance, and Life Insurance. These segments distribute their products through various forms of brokers, agencies, and direct marketing programs. All business segments have established relationships with reinsurance intermediaries.

•The North America Commercial P&C Insurance segment provides both commercial and consumer P&C products and services. This segment includes the business written by Chubb divisions that provide property and casualty (P&C) insurance and services to large, middle market and small commercial businesses in the U.S., Canada, and Bermuda. This segment includes our retail divisions: Major Accounts, Commercial Insurance, including Small Commercial Insurance; and our

wholesale and specialty divisions: Westchester and Chubb Bermuda. These divisions write a variety of coverages, including property, casualty, workers’ compensation, package policies, risk management, financial lines, marine, construction, environmental, medical risk, cyber risk, surety, and excess casualty; as well as group accident and health (A&H) insurance.

•The North America Personal P&C Insurance segment includes the business written by Chubb Personal Risk Services division, which includes high net worth personal lines business, with operations in the U.S. and Canada. This segment provides affluent and high net worth individuals and families with homeowners, automobile and collector cars, valuable articles (including fine arts), personal and excess liability, travel insurance, and recreational marine insurance and services.

•The North America Agricultural Insurance segment includes the business written by Rain and Hail Insurance Service, Inc. in the U.S. and Canada, which provides comprehensive multiple peril crop insurance (MPCI) and crop-hail insurance, and Chubb Agribusiness, which offers farm and ranch property as well as specialty P&C coverages, including commercial agriculture products.

•The Overseas General Insurance segment includes the business written by two Chubb divisions that provides both commercial and consumer P&C insurance and services in the 51 countries and territories outside of North America where the company operates. Chubb International provides commercial P&C, A&H and traditional and specialty personal lines for large corporations, middle markets and small customers through retail brokers, agents and other channels locally around the world. Chubb Global Markets (CGM) provides commercial P&C excess and surplus lines and A&H through wholesale brokers in the London market and through Lloyd’s. These divisions write a variety of coverages, including traditional commercial P&C, specialty categories such as financial lines, marine, energy, aviation, political risk and construction, as well as group A&H and traditional and specialty personal lines.

•The Global Reinsurance segment includes the reinsurance business written by Chubb Tempest Re, comprising Chubb Tempest Re Bermuda, Chubb Tempest Re USA, Chubb Tempest Re International, and Chubb Tempest Re Canada. Chubb Tempest Re provides a broad range of traditional and specialty reinsurance coverages to a diverse array of primary P&C companies, including small, mid-sized, and multinational ceding companies.

•The Life Insurance segment includes international life operations written by Chubb Life and Chubb Tempest Life Re, and the North American supplemental A&H and life business of Combined Insurance.

Corporate primarily includes the results of all run-off asbestos and environmental (A&E) exposures, run-off Brandywine business, Westchester specialty operations for 1996 and prior years, and certain other non-A&E run-off exposures. In addition, Corporate includes the results of our non-insurance companies including Chubb Limited, Chubb Group Management and Holdings Ltd., and Chubb INA Holdings Inc. Our exposure to A&E claims principally arises out of liabilities acquired when we purchased Westchester Specialty in 1998, CIGNA’s P&C business in 1999, and The Chubb Corporation (Chubb Corp) in 2016.

In addition, revenue and expenses managed at the corporate level, including realized gains and losses, interest expense, the non-operating income of our partially-owned entities, Chubb integration expenses and income taxes are reported within Corporate. In addition, the amortization expense of purchased intangibles, amortization of the fair value adjustment on acquired invested assets and assumed long-term debt as part of the Chubb Corp acquisition are considered Corporate costs as these are incurred by the overall company. The Chief Executive Officer does not manage segment results or allocate resources to segments when considering these costs and they are therefore excluded from our definition of segment income (loss).

Management uses underwriting income (loss) as the basis for segment performance. Chubb calculates underwriting income (loss) by subtracting Losses and loss expenses, Policy benefits, Policy acquisition costs, and Administrative expenses from Net premiums earned. Segment income (loss) includes underwriting income (loss), net investment income (loss), and other operating income and expense items such as each segment's share of the operating income (loss) related to partially-owned insurance companies and miscellaneous income and expense items for which the segments are held accountable. Our main measure of segment performance is Segment income (loss), which also includes amortization of purchased intangibles acquired by the segment. We determined that this definition of segment income (loss) is appropriate and aligns with how the business is managed. We continue to evaluate our segments as our business continues to evolve and may further refine our segments and segment income (loss) measures. To calculate Segment income (loss), include Net investment income (loss), Other (income) expense, and Amortization expense of purchased intangibles. Certain items are presented in a different manner for segment reporting purposes than in the Consolidated Financial Statements. These items are reconciled to the consolidated presentation in the Segment measure reclass column below and include:

•Losses and loss expenses include realized gains and losses on crop derivatives. These derivatives were purchased to provide economic benefit, in a manner similar to reinsurance protection, in the event that a significant decline in commodity pricing impacts underwriting results. We view gains and losses on these derivatives as part of the results of our underwriting operations, and therefore, realized gains (losses) from these derivatives are reclassified to losses and loss expenses.

•Policy benefits include gains and losses from fair value changes in separate account assets, as well as the offsetting movement in separate account liabilities. The gains and losses from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP have been reclassified from Other (income) expense. We view gains and losses from fair value changes in both separate account assets and liabilities as part of the results of our underwriting operations, and therefore these gains and losses are reclassified to policy benefits.

•Net investment income includes investment income reclassified from Other (income) expense related to partially-owned investment companies (private equity partnerships) where our ownership interest is in excess of three percent. We view investment income from these equity-method private equity partnerships as net investment income.

The following tables present the Statement of Operations by segment:


For the Year Ended December 31, 2020 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated
Net premiums written	$	14,474	$	4,920	$	1,846	$	9,335	$	731	$	2,514	$	—	$	—	$	33,820
Net premiums earned	13,964		4,866		1,822		9,285		698		2,482		—		—		33,117
Losses and loss expenses	10,129		3,187		1,544		5,255		435		724		435		1		21,710
Policy benefits	—		—		—		—		—		726		—		58		784
Policy acquisition costs	1,942		974		123		2,568		174		766		—		—		6,547
Administrative expenses	1,006		270		9		1,034		37		320		303		—		2,979
Underwriting income (loss)	887		435		146		428		52		(54)		(738)		(59)		1,097
Net investment income (loss)	2,061		260		30		534		307		385		(87)		(115)		3,375
Other (income) expense	23		5		1		13		2		(74)		(791)		(173)		(994)
Amortization expense of purchased intangibles	—		11		27		45		—		4		203		—		290
Segment income (loss)	$	2,925	$	679	$	148	$	904	$	357	$	401	$	(237)	$	(1)	$	5,176
Net realized gains (losses)													(499)		1		(498)
Interest expense													516		—		516
Income tax expense													629		—		629
Net income (loss)													$	(1,881)	$	—	$	3,533


For the Year Ended December 31, 2019 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated
Net premiums written	$	13,375	$	4,787	$	1,810	$	9,262	$	649	$	2,392	$	—	$	—	$	32,275
Net premiums earned	12,922		4,694		1,795		8,882		654		2,343		—		—		31,290
Losses and loss expenses	8,206		3,043		1,616		4,606		352		757		158		(8)		18,730
Policy benefits	—		—		—		—		—		696		—		44		740
Policy acquisition costs	1,831		948		84		2,501		169		620		—		—		6,153
Administrative expenses	1,028		286		6		1,033		35		323		319		—		3,030
Underwriting income (loss)	1,857		417		89		742		98		(53)		(477)		(36)		2,637
Net investment income (loss)	2,109		258		30		588		279		373		(125)		(86)		3,426
Other (income) expense	24		3		1		12		1		(48)		(459)		(130)		(596)
Amortization expense of purchased intangibles	—		12		28		45		—		2		218		—		305
Segment income (loss)	$	3,942	$	660	$	90	$	1,273	$	376	$	366	$	(361)	$	8	$	6,354
Net realized gains (losses) including OTTI													(522)		(8)		(530)
Interest expense													552		—		552
Chubb integration expenses													23		—		23
Income tax expense													795		—		795
Net income (loss)													$	(2,253)	$	—	$	4,454


For the Year Ended December 31, 2018 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated
Net premiums written	$	12,485	$	4,674	$	1,577	$	8,902	$	671	$	2,270	$	—	$	—	$	30,579
Net premiums earned	12,402		4,593		1,569		8,612		670		2,218		—		—		30,064
Losses and loss expenses	8,000		3,229		1,114		4,429		479		766		53		(3)		18,067
Policy benefits	—		—		—		—		—		628		—		(38)		590
Policy acquisition costs	1,829		939		79		2,346		162		557		—		—		5,912
Administrative expenses	966		269		(9)		1,014		41		310		295		—		2,886
Underwriting income (loss)	1,607		156		385		823		(12)		(43)		(348)		41		2,609
Net investment income (loss)	2,061		236		28		622		289		341		(209)		(63)		3,305
Other (income) expense	3		1		2		3		—		(12)		(406)		(25)		(434)
Amortization expense of purchased intangibles	—		13		28		41		—		2		255		—		339
Segment income (loss)	$	3,665	$	378	$	383	$	1,401	$	277	$	308	$	(406)	$	3	$	6,009
Net realized gains (losses) including OTTI													(649)		(3)		(652)
Interest expense													641		—		641
Chubb integration expenses													59		—		59
Income tax expense													695		—		695
Net income (loss)													$	(2,450)	$	—	$	3,962

Underwriting assets are reviewed in total by management for purposes of decision-making. Other than Unpaid losses and loss expenses, Future policy benefits, Reinsurance recoverables, Goodwill and Other intangible assets, Chubb does not allocate assets to its segments.

The following table presents net premiums earned for each segment by line of business:



	For the Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
North America Commercial P&C Insurance
Property & other short-tail lines	$	2,423	$	1,987	$	1,861
Casualty & all other	10,812		10,136		9,773
A&H	729		799		768
Total North America Commercial P&C Insurance	13,964		12,922		12,402
North America Personal P&C Insurance
Personal automobile	822		829		803
Personal homeowners	3,327		3,183		3,127
Personal other	717		682		663
Total North America Personal P&C Insurance	4,866		4,694		4,593
North America Agricultural Insurance	1,822		1,795		1,569
Overseas General Insurance
Property & other short-tail lines	2,468		2,244		2,134
Casualty & all other	2,738		2,494		2,429
Personal lines	1,981		1,896		1,784
A&H	2,098		2,248		2,265
Total Overseas General Insurance	9,285		8,882		8,612
Global Reinsurance
Property	104		131		123
Property catastrophe	173		142		170
Casualty & all other	421		381		377
Total Global Reinsurance	698		654		670
Life Insurance
Life	1,317		1,101		1,022
A&H	1,165		1,242		1,196
Total Life Insurance	2,482		2,343		2,218
Total net premiums earned	$	33,117	$	31,290	$	30,064

The following table presents net premiums earned by geographic region. Allocations have been made on the basis of location of risk:


	North America		Europe (1)		Asia Pacific / Far East		Latin America
2020	70	%	11	%	12	%	7	%
2019	70	%	11	%	12	%	7	%
2018	70	%	11	%	12	%	7	%

(1) Europe includes Eurasia and Africa regions.

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

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Related party transactions

Earnings per share

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Earnings per share


	Year Ended December 31
(in millions of U.S. dollars, except share and per share data)	2020		2019		2018
Numerator:
Net income	$	3,533	$	4,454	$	3,962
Denominator:
Denominator for basic earnings per share:
Weighted-average shares outstanding	451,602,820		455,910,463		463,629,203
Denominator for diluted earnings per share:
Share-based compensation plans	1,838,692		3,004,200		3,173,145
Weighted-average shares outstanding and assumed conversions	453,441,512		458,914,663		466,802,348
Basic earnings per share	$	7.82	$	9.77	$	8.55
Diluted earnings per share	$	7.79	$	9.71	$	8.49
Potential anti-dilutive share conversions	6,811,966		2,410,337		3,543,188

Excluded from weighted-average shares outstanding and assumed conversions is the impact of securities that would have been anti-dilutive during the respective years.

Related party transaction

12 Months Ended

Dec. 31, 2020

Starr Indemnity & Liability Company and its affiliates (collectively, Starr)

We have a number of agency and reinsurance agreements with Starr, the Chairman of which is related to a member of our senior management team. The Board has reviewed and approved our arrangements with Starr. We have agency, claims services and underwriting services agreements with various Starr subsidiaries. Under the agency agreement, we secure the ability to sell our insurance policies through Starr as one of our non-exclusive agents for writing policies, contracts, binders, or agreements of insurance or reinsurance. Under the claims services agreements, Starr adjusts the claims under policies and arranges for third party treaty and facultative agreements covering such policies. Under the underwriting services agreements, Starr underwrites insurance policies on our behalf and we agree to reinsure such policies to Starr under quota share reinsurance agreements.

The agency agreement also contains a profit-sharing arrangement based on loss ratios, triggered if Starr underwrites a minimum of $20 million of annual program business net premiums written on our behalf. No profit share commission has been payable yet under this arrangement. Transactions generated under Starr agreements were as follows:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Consolidated statement of operations
Gross premiums written	$	507	$	394	$	411
Ceded premiums written	$	253	$	207	$	188
Commissions paid	$	97	$	77	$	84
Commissions received	$	59	$	46	$	42
Losses and loss expenses	$	170	$	185	$	188
Consolidated balance sheets
Reinsurance recoverable on losses and loss expenses	$	432	$	440
Ceded reinsurance premium payable	$	80	$	56

ABR Re

We own 15.6 percent of the common equity of ABR Reinsurance Capital Holdings Ltd. and warrants to acquire 0.5 percent of additional equity. ABR Reinsurance Capital Holdings Ltd., is the parent company of ABR Reinsurance Ltd. (ABR Re), an independent reinsurance company. Through long-term arrangements, Chubb will be the sole source of reinsurance risks ceded to ABR Re, and BlackRock, Inc. will be ABR Re’s exclusive investment management service provider. As an investor, Chubb is expected to benefit from underwriting profit generated by ABR Re’s reinsuring a wide range of Chubb’s primary insurance business and the income and capital appreciation BlackRock, Inc. seeks to deliver through its investment management services. In addition, Chubb has entered into an arrangement with BlackRock, Inc. under which both Chubb and BlackRock, Inc. will be entitled to an equal share of the aggregate amount of certain fees, including underwriting and investment management performance related fees, in connection with their respective reinsurance and investment management arrangements with ABR Re.

ABR Re is a variable interest entity; however, Chubb is not the primary beneficiary and does not consolidate ABR Re because Chubb does not have the power to control and direct ABR Re’s most significant activities, including investing and underwriting. Our minority ownership interest is accounted for under the equity method of accounting. Chubb cedes premiums to ABR Re and recognizes the associated commissions.

Transactions generated under ABR Re agreements were as follows:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Consolidated statement of operations
Ceded premiums written	$	350	$	321	$	329
Commissions received	$	100	$	92	$	96

Consolidated balance sheets
Reinsurance recoverable on losses and loss expenses	$	806	$	674
Ceded reinsurance premium payable	$	67	$	62

Statutory Financial Information

12 Months Ended

Dec. 31, 2020

Statutory Financial Information [Abstract]

Statutory financial information

Our subsidiaries file financial statements prepared in accordance with statutory accounting practices prescribed or permitted by insurance regulators. Statutory accounting differs from GAAP in the reporting of certain reinsurance contracts, investments, subsidiaries, acquisition expenses, fixed assets, deferred income taxes, and certain other items. Some jurisdictions impose complex regulatory requirements on insurance companies while other jurisdictions impose fewer requirements. In some jurisdictions, we must obtain licenses issued by governmental authorities to conduct local insurance business. These licenses may be subject to reserves and minimum capital and solvency tests. Jurisdictions may impose fines, censure, and/or criminal sanctions for violation of regulatory requirements. The 2020 amounts below are based on estimates.

Chubb's insurance and reinsurance subsidiaries are subject to insurance laws and regulations in the jurisdictions in which they operate. These regulations include restrictions that limit the amount of dividends or other distributions, such as loans or cash advances, available to shareholders without prior approval of the local insurance regulatory authorities. The amount of dividends available to be paid in 2021 without prior approval totals $6.4 billion.

The statutory capital and surplus of our insurance subsidiaries met regulatory requirements for 2020, 2019, and 2018. The minimum amounts of statutory capital and surplus necessary to satisfy regulatory requirements was $29.4 billion and $26.7 billion for December 31, 2020 and 2019, respectively. These minimum regulatory capital requirements were significantly lower than the corresponding amounts required by the rating agencies which review Chubb’s insurance and reinsurance subsidiaries.

The following tables present the combined statutory capital and surplus and statutory net income (loss) of our Property and casualty and Life subsidiaries:


	December 31
(in millions of U.S. dollars)	2020		2019
Statutory capital and surplus
Property and casualty	$	45,964	$	43,077
Life	$	1,641	$	1,573


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Statutory net income (loss)
Property and casualty	$	4,294	$	6,046	$	7,521
Life	$	(247)	$	(210)	$	(102)

Several insurance subsidiaries follow accounting practices prescribed or permitted by the jurisdiction of domicile that differ from the applicable local statutory practice. The application of prescribed or permitted accounting practices does not have a material impact on Chubb's statutory surplus and income. As prescribed by the Restructuring discussed previously in Note 7, certain of our U.S. subsidiaries discount certain A&E liabilities, which increased statutory capital and surplus by approximately $140 million and $147 million at December 31, 2020 and 2019, respectively.

Federal Insurance Company (Federal), a direct subsidiary of Chubb INA Holdings Inc., has a permitted practice granted by the Indiana Department of Insurance that relates to its investments in foreign subsidiaries and affiliates. Under Statement of Statutory Accounting Principles No. 97, Investments in Subsidiary, Controlled and Affiliated Entities, in order for a reporting entity to admit its investments in foreign subsidiaries and affiliates, audited financial statements of the subsidiary or affiliate must be obtained to support the carrying value. Such financial statements must be prepared in accordance with U.S. GAAP, or alternatively, in accordance with the local statutory requirements in the subsidiary’s or affiliate’s country of domicile, with an audited footnote reconciliation of net income and shareholder’s equity as reported to a U.S. GAAP basis. With the explicit permission of the Indiana Department of Insurance, Federal obtains audited financial statements for its admitted foreign subsidiaries and affiliates, which had an aggregate carrying value of approximately $55 million and $54 million at December 31, 2020 and 2019, respectively, prepared in accordance with their respective local statutory requirements and supplemented with a separate unaudited reconciliation of shareholder’s equity as reported to a U.S. GAAP basis.

Information provided in connection with outstanding debt of subsidiaries

12 Months Ended

Dec. 31, 2020

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]

Information provided in connection with outstanding debt of subsidiaries

The following tables present condensed consolidating financial information at December 31, 2020 and 2019, and for the years ended December 31, 2020, 2019, and 2018 for Chubb Limited (Parent Guarantor) and Chubb INA Holdings Inc. (Subsidiary Issuer). The Subsidiary Issuer is an indirect 100 percent-owned subsidiary of the Parent Guarantor. The Parent Guarantor fully and unconditionally guarantees certain of the debt of the Subsidiary Issuer. Condensed consolidating financial information of the Parent Guarantor and Subsidiary Issuer are presented on the equity method of accounting. The revenues and expenses and cash flows of the subsidiaries of the Subsidiary Issuer are presented in the Other Chubb Limited Subsidiaries column on a combined basis.

Condensed Consolidating Balance Sheet at December 31, 2020


(in millions of U.S. dollars)	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
Assets
Investments	$	—	$	197	$	118,472	$	—	$	118,669
Cash (1)	84		1		1,934		(272)		1,747
Restricted Cash	—		—		89		—		89
Insurance and reinsurance balances receivable	—		—		13,926		(3,446)		10,480
Reinsurance recoverable on losses and loss expenses	—		—		25,217		(9,625)		15,592
Reinsurance recoverable on policy benefits	—		—		299		(93)		206
Value of business acquired	—		—		263		—		263
Goodwill and other intangible assets	—		—		21,211		—		21,211
Investments in subsidiaries	56,148		55,231		—		(111,379)		—
Due from subsidiaries and affiliates, net	3,522		—		171		(3,693)		—

Other assets	10		463		23,921		(1,877)		22,517
Total assets	$	59,764	$	55,892	$	205,503	$	(130,385)	$	190,774
Liabilities
Unpaid losses and loss expenses	$	—	$	—	$	77,180	$	(9,369)	$	67,811
Unearned premiums	—		—		18,853		(1,201)		17,652
Future policy benefits	—		—		5,806		(93)		5,713
Due to subsidiaries and affiliates, net	—		3,008		685		(3,693)		—
Affiliated notional cash pooling programs(1)	—		272		—		(272)		—
Repurchase agreements	—		—		1,405		—		1,405

Long-term debt	—		14,948		—		—		14,948
Trust preferred securities	—		308		—		—		308
Other liabilities	323		1,418		26,133		(4,378)		23,496
Total liabilities	323		19,954		130,062		(19,006)		131,333
Total shareholders’ equity	59,441		35,938		75,441		(111,379)		59,441
Total liabilities and shareholders’ equity	$	59,764	$	55,892	$	205,503	$	(130,385)	$	190,774

(1) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Balance Sheet at December 31, 2019


(in millions of U.S. dollars)	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
Assets
Investments	$	—	$	1,013	$	108,221	$	—	$	109,234
Cash (1)	2		442		1,093		—		1,537
Restricted Cash	—		—		109		—		109
Insurance and reinsurance balances receivable	—		—		12,920		(2,563)		10,357
Reinsurance recoverable on losses and loss expenses	—		—		24,780		(9,599)		15,181
Reinsurance recoverable on policy benefits	—		—		292		(95)		197
Value of business acquired	—		—		306		—		306
Goodwill and other intangible assets	—		—		21,359		—		21,359
Investments in subsidiaries	50,853		52,076		—		(102,929)		—
Due from subsidiaries and affiliates, net	4,776		—		—		(4,776)		—
Other assets	12		408		20,072		(1,829)		18,663
Total assets	$	55,643	$	53,939	$	189,152	$	(121,791)	$	176,943
Liabilities
Unpaid losses and loss expenses	$	—	$	—	$	71,916	$	(9,226)	$	62,690
Unearned premiums	—		—		17,978		(1,207)		16,771
Future policy benefits	—		—		5,468		(95)		5,373
Due to subsidiaries and affiliates, net	—		4,446		330		(4,776)		—

Repurchase agreements	—		—		1,416		—		1,416
Short-term debt	—		1,298		1		—		1,299
Long-term debt	—		13,559		—		—		13,559
Trust preferred securities	—		308		—		—		308
Other liabilities	312		1,649		21,793		(3,558)		20,196
Total liabilities	312		21,260		118,902		(18,862)		121,612
Total shareholders’ equity	55,331		32,679		70,250		(102,929)		55,331
Total liabilities and shareholders’ equity	$	55,643	$	53,939	$	189,152	$	(121,791)	$	176,943

(1)Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.

Condensed Consolidating Statements of Operations and Comprehensive Income


For the Year Ended December 31, 2020	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net premiums written	$	—	$	—	$	33,820	$	—	$	33,820
Net premiums earned	—		—		33,117		—		33,117
Net investment income	(1)		6		3,370		—		3,375
Equity in earnings of subsidiaries	3,457		2,052		—		(5,509)		—
Net realized gains (losses)	20		(397)		(121)		—		(498)
Losses and loss expenses	—		—		21,710		—		21,710
Policy benefits	—		—		784		—		784
Policy acquisition costs and administrative expenses	94		(130)		9,562		—		9,526
Interest (income) expense	(136)		596		56		—		516
Other (income) expense	(39)		(24)		(931)		—		(994)
Amortization of purchased intangibles	—		—		290		—		290

Income tax expense (benefit)	24		(181)		786		—		629
Net income	$	3,533	$	1,400	$	4,109	$	(5,509)	$	3,533
Comprehensive income	$	5,783	$	3,236	$	6,512	$	(9,748)	$	5,783

Condensed Consolidating Statements of Operations and Comprehensive Income


For the Year Ended December 31, 2019	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net premiums written	$	—	$	—	$	32,275	$	—	$	32,275
Net premiums earned	—		—		31,290		—		31,290
Net investment income	1		(15)		3,440		—		3,426
Equity in earnings of subsidiaries	4,307		3,022		—		(7,329)		—
Net realized gains (losses) including OTTI	(17)		(31)		(482)		—		(530)
Losses and loss expenses	—		—		18,730		—		18,730
Policy benefits	—		—		740		—		740
Policy acquisition costs and administrative expenses	92		(26)		9,117		—		9,183
Interest (income) expense	(243)		705		90		—		552
Other (income) expense	(27)		6		(575)		—		(596)
Amortization of purchased intangibles	—		—		305		—		305
Chubb integration expenses	1		2		20		—		23
Income tax expense (benefit)	14		(175)		956		—		795
Net income	$	4,454	$	2,464	$	4,865	$	(7,329)	$	4,454
Comprehensive income	$	7,521	$	4,988	$	7,922	$	(12,910)	$	7,521

Condensed Consolidating Statements of Operations and Comprehensive Income (Loss)


For the Year Ended December 31, 2018	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net premiums written	$	—	$	—	$	30,579	$	—	$	30,579
Net premiums earned	—		—		30,064		—		30,064
Net investment income	6		13		3,286		—		3,305
Equity in earnings of subsidiaries	3,753		2,578		—		(6,331)		—
Net realized gains (losses) including OTTI	—		117		(769)		—		(652)
Losses and loss expenses	—		—		18,067		—		18,067
Policy benefits	—		—		590		—		590
Policy acquisition costs and administrative expenses	87		(58)		8,769		—		8,798
Interest (income) expense	(299)		806		134		—		641
Other (income) expense	(24)		26		(436)		—		(434)
Amortization of purchased intangibles	—		—		339		—		339
Chubb integration expenses	14		1		44		—		59
Income tax expense (benefit)	19		(148)		824		—		695
Net income	$	3,962	$	2,081	$	4,250	$	(6,331)	$	3,962
Comprehensive income (loss)	$	1,242	$	(27)	$	1,808	$	(1,781)	$	1,242

Condensed Consolidating Statement of Cash Flows


For the Year Ended December 31, 2020	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net cash flows from operating activities	$	1,933	$	274	$	10,788	$	(3,210)	$	9,785
Cash flows from investing activities
Purchases of fixed maturities available for sale	—		(49)		(26,249)		—		(26,298)
Purchases of fixed maturities held to maturity	—		—		(202)		—		(202)
Purchases of equity securities	—		—		(6,419)		—		(6,419)
Sales of fixed maturities available for sale	—		9		11,368		—		11,377
Sales of equity securities	—		—		3,880		—		3,880
Maturities and redemptions of fixed maturities available for sale	—		50		12,400		—		12,450
Maturities and redemptions of fixed maturities held to maturity	—		—		995		—		995
Net change in short-term investments	—		772		(853)		—		(81)
Net derivative instruments settlements	—		55		(168)		—		(113)


Private equity contributions	—		—		(1,924)		—		(1,924)
Private equity distributions	—		—		907		—		907
Payment, including deposit, for Huatai Group interest	—		—		(1,623)		—		(1,623)

Capital contribution	(1,200)		(72)		—		1,272		—

Other	(2)		4		(472)		—		(470)
Net cash flows from (used for) investing activities	(1,202)		769		(8,360)		1,272		(7,521)
Cash flows from financing activities
Dividends paid on Common Shares	(1,388)		—		—		—		(1,388)
Common Shares repurchased	(523)		—		—		—		(523)
Proceeds from issuance of long-term debt	—		988		—		—		988
Proceeds from issuance of repurchase agreements	—		—		2,354		—		2,354
Repayment of long-term debt	—		(1,301)		—		—		(1,301)
Repayment of repurchase agreements	—		—		(2,354)		—		(2,354)
Proceeds from share-based compensation plans	—		—		145		—		145
Advances (to) from affiliates	1,265		(1,438)		173		—		—
Dividends to parent company	—		—		(3,210)		3,210		—
Capital contribution	—		—		1,272		(1,272)		—
Net proceeds from affiliated notional cash pooling programs(1)	—		272		—		(272)		—
Policyholder contract deposits and other	—		—		470		—		470
Policyholder contract withdrawals and other	—		—		(386)		—		(386)
Other	—		—		(87)		—		(87)
Net cash flows used for financing activities	(646)		(1,479)		(1,623)		1,666		(2,082)
Effect of foreign currency rate changes on cash and restricted cash	(3)		(5)		16		—		8
Net increase (decrease) in cash and restricted cash	82		(441)		821		(272)		190
Cash and restricted cash – beginning of year (1)	2		442		1,202		—		1,646
Cash and restricted cash – end of year (1)	$	84	$	1	$	2,023	$	(272)	$	1,836

(1)Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Statement of Cash Flows


For the Year Ended December 31, 2019	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net cash flows from operating activities	$	412	$	2,926	$	6,878	$	(3,874)	$	6,342
Cash flows from investing activities
Purchases of fixed maturities available for sale	—		(21)		(25,825)		—		(25,846)

Purchases of fixed maturities held to maturity	—		—		(229)		—		(229)
Purchases of equity securities	—		—		(531)		—		(531)
Sales of fixed maturities available for sale	—		1		13,115		—		13,116

Sales of equity securities	—		—		611		—		611
Maturities and redemptions of fixed maturities available for sale	—		41		8,998		—		9,039
Maturities and redemptions of fixed maturities held to maturity	—		—		946		—		946
Net change in short-term investments	—		(808)		(309)		—		(1,117)
Net derivative instruments settlements	—		(74)		(629)		—		(703)
Private equity contributions	—		—		(1,315)		—		(1,315)
Private equity distributions	—		—		1,390		—		1,390
Capital contribution	(1,000)		(110)		—		1,110		—
Acquisition of subsidiaries (net of cash acquired of $45)	—		—		(29)		—		(29)
Payment, including deposit, for Huatai Group interest	—		—		(580)		—		(580)

Other	—		(4)		(653)		—		(657)
Net cash flows used for investing activities	(1,000)		(975)		(5,040)		1,110		(5,905)
Cash flows from financing activities
Dividends paid on Common Shares	(1,354)		—		—		—		(1,354)
Common Shares repurchased	(327)		—		(1,203)		—		(1,530)
Proceeds from issuance of long-term debt	—		2,828		—		—		2,828
Proceeds from issuance of repurchase agreements	—		—		2,817		—		2,817
Repayment of long-term debt	—		(500)		(10)		—		(510)
Repayment of repurchase agreements	—		—		(2,817)		—		(2,817)
Proceeds from share-based compensation plans	—		—		204		—		204
Advances (to) from affiliates	2,301		(3,223)		922		—		—
Dividends to parent company	—		—		(3,874)		3,874		—
Capital contribution	—		—		1,110		(1,110)		—
Net proceeds payments to affiliated notional cash pooling programs(1)	(35)		(617)		—		652		—
Policyholder contract deposits	—		—		514		—		514
Policyholder contract withdrawals	—		—		(303)		—		(303)

Net cash flows from (used for) financing activities	585		(1,512)		(2,640)		3,416		(151)
Effect of foreign currency rate changes on cash and restricted cash	4		1		15		—		20
Net increase (decrease) in cash and restricted cash	1		440		(787)		652		306
Cash and restricted cash – beginning of year (1)	1		2		1,989		(652)		1,340
Cash and restricted cash – end of year (1)	$	2	$	442	$	1,202	$	—	$	1,646

(1)Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Statement of Cash Flows


For the Year Ended December 31, 2018	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net cash flows from operating activities	$	256	$	4,654	$	5,878	$	(5,308)	$	5,480
Cash flows from investing activities
Purchases of fixed maturities available for sale	—		(38)		(24,697)		—		(24,735)

Purchases of fixed maturities held to maturity	—		—		(456)		—		(456)
Purchases of equity securities	—		—		(207)		—		(207)
Sales of fixed maturities available for sale	—		11		14,019		—		14,030

Sales of equity securities	—		—		315		—		315
Maturities and redemptions of fixed maturities available for sale	—		17		7,335		—		7,352
Maturities and redemptions of fixed maturities held to maturity	—		—		1,124		—		1,124
Net change in short-term investments	—		3		513		—		516
Net derivative instruments settlements	—		(7)		23		—		16
Private equity contributions	—		—		(1,337)		—		(1,337)
Private equity distributions	—		—		980		—		980

Capital contribution	(1,475)		(3,550)		—		5,025		—
Other	—		(18)		(515)		—		(533)
Net cash flows used for investing activities	(1,475)		(3,582)		(2,903)		5,025		(2,935)
Cash flows from financing activities
Dividends paid on Common Shares	(1,337)		—		—		—		(1,337)
Common Shares repurchased	—		—		(1,044)		—		(1,044)
Proceeds from issuance of long-term debt	—		2,171		—		—		2,171
Proceeds from issuance of repurchase agreements	—		—		2,029		—		2,029
Repayment of long-term debt	—		(2,000)		(1)		—		(2,001)
Repayment of repurchase agreements	—		—		(2,019)		—		(2,019)
Proceeds from share-based compensation plans	—		—		115		—		115
Advances (to) from affiliates	2,519		(1,744)		(775)		—		—
Dividends to parent company	—		—		(5,308)		5,308		—
Capital contribution	—		—		5,025		(5,025)		—
Net payments to affiliated notional cash pooling programs(1)	35		502		—		(537)		—
Policyholder contract deposits	—		—		453		—		453
Policyholder contract withdrawals	—		—		(358)		—		(358)

Net cash flows from (used for) financing activities	1,217		(1,071)		(1,883)		(254)		(1,991)
Effect of foreign currency rate changes on cash and restricted cash	—		—		(65)		—		(65)
Net increase (decrease) in cash and restricted cash	(2)		1		1,027		(537)		489
Cash and restricted cash – beginning of year (1)	3		1		962		(115)		851
Cash and restricted cash – end of year (1)	$	1	$	2	$	1,989	$	(652)	$	1,340

(1)Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018 and 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Schedule I

12 Months Ended

Dec. 31, 2020

SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]

Schedule I: SUMMARY OF INVESTEMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES

SUMMARY OF INVESTMENTS – OTHER THAN INVESTMENTS IN RELATED PARTIES


December 31, 2020 (in millions of U.S. dollars)	Cost or Amortized Cost, Net (1)		Fair Value		Amount at Which Shown in the Balance Sheet
Fixed maturities available for sale
U.S. Treasury / Agency	$	2,471	$	2,670	$	2,670
Non-U.S.	24,588		26,354		26,354
Corporate and asset-backed securities	34,081		36,331		36,331
Mortgage-backed securities	17,456		18,470		18,470
Municipal	6,572		6,874		6,874
Total fixed maturities available for sale	85,168		90,699		90,699
Fixed maturities held to maturity
U.S. Treasury / Agency	1,392		1,452		1,392
Non-U.S.	1,288		1,405		1,288
Corporate and asset-backed securities	2,150		2,438		2,150
Mortgage-backed securities	1,999		2,146		1,999
Municipal	4,824		5,069		4,824
Total fixed maturities held to maturity	11,653		12,510		11,653
Equity securities
Industrial, miscellaneous, and all other	4,027		4,027		4,027
Short-term investments	4,349		4,345		4,345
Other investments (2)	7,826		7,826		7,826
Total investments - other than investments in related parties	$	113,023	$	119,407	$	118,550

(1) Net of valuation allowance for expected credit losses.

(2) Excludes $119 million of related party investments.

Schedule II

12 Months Ended

Dec. 31, 2020

Condensed Financial Information Disclosure [Abstract]

Schedule II - CONDENSED FINANCIAL INFORMATION OF REGISTRANT

CONDENSED FINANCIAL INFORMATION OF REGISTRANT

BALANCE SHEETS (Parent Company Only)


	December 31		December 31
(in millions of U.S. dollars)	2020		2019
Assets
Investments in subsidiaries and affiliates on equity basis	$	56,148	$	50,853


Total investments	56,148		50,853

Cash	84		2
Due from subsidiaries and affiliates, net	3,522		4,776
Other assets	10		12
Total assets	$	59,764	$	55,643
Liabilities

Accounts payable, accrued expenses, and other liabilities	$	323	$	312

Total liabilities	323		312
Shareholders' equity
Common Shares	11,064		11,121
Common Shares in treasury	(3,644)		(3,754)
Additional paid-in capital	9,815		11,203
Retained earnings	39,337		36,142
Accumulated other comprehensive income	2,869		619
Total shareholders' equity	59,441		55,331
Total liabilities and shareholders' equity	$	59,764	$	55,643

The condensed financial information should be read in conjunction with the Consolidated Financial Statements and notes thereto.

CONDENSED FINANCIAL INFORMATION OF REGISTRANT

STATEMENTS OF OPERATIONS (Parent Company Only)


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Revenues
Investment income (1)	$	155	$	227	$	305
Equity in net income of subsidiaries and affiliates	3,457		4,307		3,753

	3,612		4,534		4,058
Expenses
Administrative and other (income) expense	55		65		63
Chubb integration expenses	—		1		14
Income tax expense	24		14		19
	79		80		96
Net income	$	3,533	$	4,454	$	3,962
Comprehensive income	$	5,783	$	7,521	$	1,242

(1)Includes net investment income, interest income, and net realized gains (losses).

The condensed financial information should be read in conjunction with the Consolidated Financial Statements and notes thereto.

STATEMENTS OF CASH FLOWS (Parent Company Only)


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Net cash flows from operating activities (1)	$	1,933	$	412	$	256
Cash flows from investing activities


Capital contribution	(1,200)		(1,000)		(1,475)
Other	(2)		—		—
Net cash flows used for investing activities	(1,202)		(1,000)		(1,475)
Cash flows from financing activities
Dividends paid on Common Shares	(1,388)		(1,354)		(1,337)
Common Shares repurchased	(523)		(327)		—
Advances from affiliates	1,265		2,301		2,519
Net proceeds from (payments to) affiliated notional cash pooling programs (2)	—		(35)		35
Net cash flows from (used for) financing activities	(646)		585		1,217
Effect of foreign currency rate changes on cash and restricted cash	(3)		4		—
Net increase (decrease) in cash and restricted cash	82		1		(2)
Cash and restricted cash – beginning of year	2		1		3
Cash and restricted cash – end of year	$	84	$	2	$	1

(1) Includes cash dividends received from subsidiaries of $2.0 billion, $200 million, and $75 million in 2020, 2019, and 2018, respectively.

(2) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.

The condensed financial information should be read in conjunction with the Consolidated Financial Statements and notes thereto.

Schedule IV

12 Months Ended

Dec. 31, 2020

SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]

SUPPLEMENTAL INFORMATION CONCERNING REINSURANCE


Premiums Earned
For the years ended December 31, 2020, 2019, and 2018 (in millions of U.S. dollars, except for percentages)	Direct Amount		Ceded To Other Companies		Assumed From Other Companies		Net Amount		Percentage of Amount Assumed to Net
2020
Property and Casualty	$	31,546	$	6,782	$	3,044	$	27,808	11	%
Accident and Health	4,249		368		111		3,992		3	%
Life	1,242		93		168		1,317		13	%
Total	$	37,037	$	7,243	$	3,323	$	33,117	10	%
2019
Property and Casualty	$	30,339	$	7,236	$	2,797	$	25,900	11	%
Accident and Health	4,546		376		119		4,289		3	%
Life	991		81		191		1,101		17	%
Total	$	35,876	$	7,693	$	3,107	$	31,290	10	%
2018
Property and Casualty	$	28,793	$	6,792	$	2,812	$	24,813	11	%
Accident and Health	4,409		342		162		4,229		4	%
Life	906		85		201		1,022		20	%
Total	$	34,108	$	7,219	$	3,175	$	30,064	11	%

Schedule VI

12 Months Ended

Dec. 31, 2020

SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]

SUPPLEMENTARY INFORMATION CONCERNING PROPERTY AND CASUALTY OPERATIONS


As of and for the years ended December 31, 2020, 2019, and 2018 (in millions of U.S. dollars)
	Deferred Policy Acquisition Costs		Net Reserves for Unpaid Losses and Loss Expenses		Unearned Premiums		Net Premiums Earned		Net Investment Income		Net Losses and Loss Expenses Incurred Related to					Amortization of Deferred Policy Acquisition Costs		Net Paid Losses and Loss Expenses		Net Premiums Written
												Current Year		Prior Year
2020	$	4,244	$	53,164	$	17,652	$	31,800	$	3,074		$	22,124	$	(414)	$	6,076	$	17,434	$	32,471
2019	$	4,161	$	48,509	$	16,771	$	30,189	$	3,141		$	19,575	$	(845)	$	5,831	$	18,473	$	31,126
2018	$	3,926	$	48,271	$	15,532	$	29,042	$	3,047		$	19,048	$	(981)	$	5,630	$	18,340	$	29,505

Summary of significant accounting policies (Policies)	12 Months Ended
Summary of significant accounting policies (Policies)	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation	Basis of presentation Chubb Limited is a holding company incorporated in Zurich, Switzerland. Chubb Limited, through its subsidiaries, provides a broad range of insurance and reinsurance products to insureds worldwide. Our results are reported through the following business segments: North America Commercial P&C Insurance, North America Personal P&C Insurance, North America Agricultural Insurance, Overseas General Insurance, Global Reinsurance, and Life Insurance. Refer to Note 15 for additional information. The accompanying Consolidated Financial Statements, which include the accounts of Chubb Limited and its subsidiaries (collectively, Chubb, we, us, or our), have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and, in the opinion of management, reflect all adjustments necessary for a fair statement of the results and financial position for such periods. All significant intercompany accounts and transactions, including internal reinsurance transactions, have been eliminated. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Amounts included in the Consolidated Financial Statements reflect our best estimates and assumptions; actual amounts could differ materially from these estimates. Chubb's principal estimates include: •unpaid loss and loss expense reserves, including long-tail asbestos and environmental (A&E) reserves and non-A&E casualty exposures; •future policy benefits reserves; •amortization of deferred policy acquisition costs and value of business acquired (VOBA); •reinsurance recoverable, including a valuation allowance for uncollectible reinsurance; •the assessment of risk transfer for certain structured insurance and reinsurance contracts; •the valuation of the investment portfolio and assessment of valuation allowance for expected credit losses; •the valuation of deferred income taxes; •the valuation of derivative instruments related to guaranteed living benefits (GLB); •the valuation and amortization of purchased intangibles; and •the assessment of goodwill for impairment.
Premiums	Premiums Premiums are generally recorded as written upon inception of the policy. For multi-year policies for which premiums written are payable in annual installments, only the current annual premium is included as written at policy inception due to the ability of the insured/reinsured to commute or cancel coverage within the policy term. The remaining annual premiums are recorded as written at each successive anniversary date within the multi-year term. For property and casualty (P&C) insurance and reinsurance products, premiums written are primarily earned on a pro-rata basis over the policy terms to which they relate. Unearned premiums represent the portion of premiums written applicable to the unexpired portion of the policies in force. For retrospectively-rated policies, written premiums are adjusted to reflect expected ultimate premiums consistent with changes to incurred losses, or other measures of exposure as stated in the policy, and earned over the policy coverage period. Mandatory reinstatement premiums assessed on reinsurance policies are earned in the period of the loss event that gave rise to the reinstatement premiums. All remaining unearned premiums are recognized over the remaining coverage period. Premiums from long-duration contracts such as certain traditional term life, whole life, endowment, and long-duration personal accident and health (A&H) policies are generally recognized as revenue when due from policyholders. Traditional life policies include those contracts with fixed and guaranteed premiums and benefits. Benefits and expenses are matched with income to result in the recognition of profit over the life of the contracts. Retroactive loss portfolio transfer (LPT) contracts in which the insured loss events occurred prior to contract inception are evaluated to determine whether they meet criteria for reinsurance accounting. If reinsurance accounting is appropriate, written premiums are fully earned and corresponding losses and loss expenses recognized at contract inception. These contracts can cause significant variances in gross premiums written, net premiums written, net premiums earned, and net incurred losses in the years in which they are written. Reinsurance contracts sold not meeting the criteria for reinsurance accounting are recorded using the deposit method as described below in Note 1 k). Reinsurance premiums assumed are based on information provided by ceding companies supplemented by our own estimates of premium when we have not received ceding company reports. Estimates are reviewed and adjustments are recorded in the period in which they are determined. Premiums are earned over the coverage terms of the related reinsurance contracts and range from one to three years.
Deferred policy acquisition costs and value of business acquired	Deferred policy acquisition costs and value of business acquired Policy acquisition costs consist of commissions (direct and ceded), premium taxes, and certain underwriting costs related directly to the successful acquisition of new or renewal insurance contracts. A VOBA intangible asset is established upon the acquisition of blocks of long-duration contracts in a business combination and represents the present value of estimated net cash flows for the contracts in force at the acquisition date. Acquisition costs and VOBA, collectively policy acquisition costs, are deferred and amortized. Amortization is recorded in Policy acquisition costs in the Consolidated statements of operations. Policy acquisition costs on P&C contracts are generally amortized ratably over the period in which premiums are earned. Policy acquisition costs on traditional long-duration contracts are amortized over the estimated life of the contracts, generally in proportion to premium revenue recognized based upon the same assumptions used in estimating the liability for future policy benefits. For non-traditional long-duration contracts, we amortize policy acquisition costs over the expected life of the contracts in proportion to expected gross profits. The effect of changes in estimates of expected gross profits is reflected in the period the estimates are revised. Policy acquisition costs are reviewed to determine if they are recoverable from future income, including investment income. Unrecoverable policy acquisition costs are expensed in the period identified. Advertising costs are expensed as incurred except for direct-response campaigns that qualify for cost deferral, principally related to long-duration A&H business produced by the Overseas General Insurance segment, which are deferred and recognized as a component of Policy acquisition costs. For individual direct-response marketing campaigns that we can demonstrate have specifically resulted in incremental sales to customers and such sales have probable future economic benefits, incremental costs directly related to the marketing campaigns are capitalized as Deferred policy acquisition costs. Deferred policy acquisition costs, including deferred marketing costs, are reviewed regularly for recoverability from future income, including investment income, and amortized in proportion to premium revenue recognized, primarily over a ten-year period, the expected economic future benefit period based upon the same assumptions used in estimating the liability for future policy benefits. The expected future benefit period is evaluated periodically based on historical results and adjusted prospectively. The amount of deferred marketing costs reported in Deferred policy acquisition costs in the Consolidated balance sheets was $226 million and $246 million at December 31, 2020 and 2019, respectively. Amortization expense for deferred marketing costs was $99 million, $109 million, and $114 million for the years ended December 31, 2020, 2019, and 2018, respectively.
Reinsurance	Reinsurance Chubb assumes and cedes reinsurance with other insurance companies to provide greater diversification of business and minimize the net loss potential arising from large risks. Ceded reinsurance contracts do not relieve Chubb of its primary obligation to policyholders. For both ceded and assumed reinsurance, risk transfer requirements must be met in order to account for a contract as reinsurance, principally resulting in the recognition of cash flows under the contract as premiums and losses. To meet risk transfer requirements, a reinsurance contract must include insurance risk, consisting of both underwriting and timing risk, and a reasonable possibility of a significant loss for the assuming entity. To assess risk transfer for certain contracts, Chubb generally develops expected discounted cash flow analyses at contract inception. Deposit accounting is used for contracts that do not meet risk transfer requirements. Deposit accounting requires that consideration received or paid be recorded in the balance sheet as opposed to recording premiums written or losses incurred in the statement of operations. Non-refundable fees on deposit contracts are earned based on the terms of the contract described below in Note 1 k). Reinsurance recoverable includes balances due from reinsurance companies for paid and unpaid losses and loss expenses and future policy benefits that will be recovered from reinsurers, based on contracts in force. The method for determining the reinsurance recoverable on unpaid losses and loss expenses incurred but not reported (IBNR) involves actuarial estimates consistent with those used to establish the associated liability for unpaid losses and loss expenses as well as a determination of Chubb's ability to cede unpaid losses and loss expenses under the terms of the reinsurance agreement. Reinsurance recoverable is presented net of a valuation allowance for uncollectible reinsurance determined based upon a review of the financial condition of reinsurers and other factors. The valuation allowance for uncollectible reinsurance is based on an estimate of the reinsurance recoverable balance that will ultimately be unrecoverable due to reinsurer insolvency, a contractual dispute, or any other reason. The valuation of this allowance includes several judgments including certain aspects of the allocation of reinsurance recoverable on IBNR claims by reinsurer and a default analysis to estimate uncollectible reinsurance. The primary components of the default analysis are reinsurance recoverable balances by reinsurer, net of collateral, and default factors used to determine the portion of a reinsurer's balance deemed uncollectible. The definition of collateral for this purpose requires some judgment and is generally limited to assets held in a Chubb-only beneficiary trust, letters of credit, and liabilities held with the same legal entity for which Chubb believes there is a contractual right of offset. The determination of the default factor is principally based on the financial strength rating of the reinsurer. Default factors require considerable judgment and are determined using the current financial strength rating, or rating equivalent, of each reinsurer as well as other key considerations and assumptions. Changes in the valuation allowance for uncollectible reinsurance recoverables are recorded in Losses and loss expenses in the Consolidated statements of operations. Our methodology to calculate the valuation allowance was consistent with the new expected credit loss guidance adopted on January 1, 2020. Therefore, there was no change to the valuation allowance upon adoption. The more significant considerations include, but are not necessarily limited to, the following: •For reinsurers that maintain a financial strength rating from a major rating agency, and for which recoverable balances are considered representative of the larger population (i.e., default probabilities are consistent with similarly rated reinsurers and payment durations conform to averages), the financial rating is based on a published source and the default factor is based on published default statistics of a major rating agency applicable to the reinsurer's particular rating class. When a recoverable is expected to be paid in a brief period of time by a highly rated reinsurer, such as certain property catastrophe claims, a default factor may not be applied; •For balances recoverable from reinsurers that are both unrated by a major rating agency and for which management is unable to determine a credible rating equivalent based on a parent, affiliate, or peer company, we determine a rating equivalent based on an analysis of the reinsurer that considers an assessment of the creditworthiness of the particular entity, industry benchmarks, or other factors as considered appropriate. We then apply the applicable default factor for that rating class. For balances recoverable from unrated reinsurers for which the ceded reserve is below a certain threshold, we generally apply a default factor of 34 percent, consistent with published statistics of a major rating agency; •For balances recoverable from reinsurers that are either insolvent or under regulatory supervision, we establish a default factor and resulting valuation allowance for uncollectible reinsurance based on reinsurer-specific facts and circumstances. Upon initial notification of an insolvency, we generally recognize an expense for a substantial portion of all balances outstanding, net of collateral, through a combination of write-offs of recoverable balances and increases to the valuation allowance for uncollectible reinsurance. When regulatory action is taken on a reinsurer, we generally recognize a default factor by estimating an expected recovery on all balances outstanding, net of collateral. When sufficient credible information becomes available, we adjust the valuation allowance for uncollectible reinsurance by establishing a default factor pursuant to information received; and •For other recoverables, management determines the valuation allowance for uncollectible reinsurance based on the specific facts and circumstances. The methods used to determine the reinsurance recoverable balance and related valuation allowance for uncollectible reinsurance are regularly reviewed and updated, and any resulting adjustments are reflected in earnings in the period identified. The methods used to determine the valuation allowance for uncollectible high deductible recoverable amounts and valuation allowance for insurance and reinsurance balances receivable are similar to the processes used to determine the valuation allowance for uncollectible reinsurance recoverable. For information on high deductible policies, refer to section h) Unpaid losses and loss expenses, below. Prepaid reinsurance premiums represent the portion of premiums ceded to reinsurers applicable to the unexpired coverage terms of the reinsurance contracts in-force. The value of reinsurance business assumed is the deferred gain or loss related to loss portfolio transfers assumed and is calculated as the difference between the estimated ultimate value of the liabilities assumed under retroactive reinsurance contracts over consideration received. The gain or loss is amortized and recorded to Losses and loss expenses based on the payment pattern of the losses assumed. The unamortized value is reviewed regularly to determine if it is recoverable based upon the terms of the contract, estimated losses and loss expenses, and anticipated investment income. Unrecoverable amounts are expensed in the period identified. The value of reinsurance business assumed at December 31, 2020 and 2019 were immaterial.
Investments	Investments Fixed maturities, equity securities, and short-term investments Fixed maturities are classified as either available for sale or held to maturity. •Available for sale (AFS) portfolio is reported at fair value, net of a valuation allowance for credit losses, with changes in fair value recorded as a separate component of AOCI in Shareholders' equity. •Held to maturity (HTM) portfolio includes securities for which we have the ability and intent to hold to maturity or redemption and is reported at amortized cost, net of a valuation allowance for credit losses. Equity securities are reported at fair value with changes in fair value recorded in net realized gains (losses) on the Consolidated statement of operations. Short-term investments comprise securities due to mature within one year of the date of purchase and are recorded at fair value which typically approximates cost. Interest, dividend income, and amortization of fixed maturity market premiums and discounts, related to these securities are recorded in Net investment income, net of investment management and custody fees, in the Consolidated statement of operations. In addition, net investment income includes the amortization of the fair value adjustment related to the acquired invested assets of The Chubb Corporation (Chubb Corp). An adjustment of $1,652 million related to the fair value of Chubb Corp’s fixed maturities securities was recorded (fair value adjustment) at the date of acquisition. At December 31, 2020, the remaining balance of this fair value adjustment was $213 million which is expected to amortize over the next two years; however, the estimate could vary materially based on current market conditions, bond calls, and the duration of the acquired investment portfolio. In addition, sales of these acquired fixed maturities would also reduce the fair value adjustment balance. For mortgage-backed securities and any other holdings for which there is a prepayment risk, prepayment assumptions are evaluated and revised as necessary. Any adjustments required due to the resultant change in effective yields and maturities are recognized prospectively. Prepayment fees or call premiums that are only payable when a security is called prior to its maturity are earned when received and reflected in Net investment income. Valuation allowance for fixed income securities Management evaluates current expected credit losses (CECL) for all HTM securities each quarter. U.S. treasury and agency securities and U.S. government agency mortgage-backed securities are assumed to have no risk of non-payment and therefore are excluded from the CECL evaluation. The remaining HTM securities are evaluated for potential credit loss on a collective pool basis. We elected to pool HTM securities by 1) external credit rating and 2) time to maturity (duration). These characteristics are the most representative of similar risk characteristics within our portfolio. Chubb pools HTM securities and calculates an expected credit loss for each pool using Moody’s corporate bond default average, corporate bond recovery rate, and an economic cycle multiplier. The multiplier is based on the leading economic index and will adjust the average default frequency for a forward-looking economic outlook. Management monitors the credit quality of HTM securities through the review of external credit ratings on a quarterly basis. Management evaluates expected credit losses (ECL) for AFS securities when fair value is below amortized cost. AFS securities are evaluated for potential credit loss on an individual security level but the evaluation may use assumptions consistent with expectations of credit losses for a group of similar securities. If management has the intent to sell or will be required to sell the security before recovery, the entire impairment loss will be recorded through income to net realized gains and losses. If management does not have the intent to sell or will not be required to sell the security before recovery, an allowance for credit losses is established and is recorded through income to net realized gains and losses, and the non-credit loss portion is recorded through other comprehensive income. Examples of criteria that are collectively evaluated to determine if a credit loss has occurred include the following: •The extent to which the fair value is less than amortized cost; •Adverse conditions related to the security, industry, or geographic area; •Downgrades in the security's credit rating by a rating agency; and •Failure of the issuer to make scheduled principal or interest payments AFS securities that meet any one of the criteria included above will be subject to a discounted cash flow analysis by comparing the present value of expected future cash flows with the amortized cost basis. Projected cash flows are driven primarily by assumptions regarding probability of default and the timing and amount of recoveries associated with defaults. Chubb developed the projected cash flows using market data, issuer-specific information, and credit ratings. In combination with contractual cash flows and the use of historical default and recovery data by Moody's Investors Service (Moody's) rating category we generate expected cash flows using the average cumulative issuer-weighted global default rates by letter rating. If the present value of expected future cash flows is less than the amortized cost, a credit loss exists and an allowance for credit losses will be recognized. If the present value of expected future cash flows is equal to or greater than the amortized cost basis, management will conclude an expected credit loss does not exist. Management reviews credit losses and the valuation allowance for expected credit losses each quarter. When all or a portion of a fixed maturity security is identified to be uncollectible and written off, the valuation allowance for expected credit losses is reduced by the same amount. In general, a security is considered uncollectible no later than when all efforts to collect contractual cash flows have been exhausted. Below are considerations for when a security may be deemed uncollectible: •We have sufficient information to determine that the issuer of the security is insolvent; •We receive notice that the issuer of the security has filed for bankruptcy, and the collectability is expected to be adversely impacted by the bankruptcy; •The issuer of a security has violated multiple debt covenants; •Amounts have been past due for a specified period of time with no response from the issuer; •A significant deterioration in the value of the collateral has occurred; •We have received correspondence from the issuer of the security indicating that it doesn’t intend to pay the contractual principal and interest. We elected to not measure an allowance for accrued investment income as uncollectible balances are written off in a timely manner, typically 30 to 45 days after uncollected balances are due. Prior to January 1, 2020, fixed income securities were evaluated individually for other-than-temporary impairment (OTTI) and a realized loss was recognized once certain criteria were met. Other investments Other investments principally comprise investment funds, limited partnerships, partially-owned investment companies, life insurance policies, policy loans, and non-qualified separate account assets. Investment funds and limited partnerships Investment funds, limited partnerships, and all other investments over which Chubb cannot exercise significant influence are accounted for as follows. Generally, we own less than three percent of the investee’s shares. •Income and expenses from these funds are reported within Net investment income. •These funds are carried at net asset value, which approximates fair value with changes in fair value recorded in net realized gains (losses) on the Consolidated statement of operations. Refer to Note 4 for a further discussion on net asset value. •As a result of the timing of the receipt of valuation data from the investment managers, these investments are generally reported on a three-month lag. •Sales of these investments are reported within Net realized gains (losses). Partially-owned investment companies Partially-owned investment companies where our ownership interest is in excess of three percent are accounted for under the equity method because Chubb exerts significant influence. These investments apply investment company accounting to determine operating results, and Chubb retains the investment company accounting in applying the equity method. •This means that investment income, realized gains or losses, and unrealized gains or losses are included in the portion of equity earnings reflected in Other (income) expense. •As a result of the timing of the receipt of valuation data from the investment managers, these investments are generally reported on a three-month lag. Other •Policy loans are carried at outstanding balance and interest income is reflected in Net investment income. •Life insurance policies are carried at policy cash surrender value and income is reflected in Other (income) expense. •Non-qualified separate account assets are supported by assets that do not qualify for separate accounting reporting under GAAP. The underlying securities are recorded on a trade date basis and carried at fair value. Unrealized gains and losses on non-qualified separate account assets are reflected in Other (income) expense. Investments in partially-owned insurance companies Investments in partially-owned insurance companies primarily represent direct investments in which Chubb has significant influence and as such, meet the requirements for equity accounting. Generally, we own twenty percent or more of the investee’s shares. We report our share of the net income or loss of the partially-owned insurance companies in Other (income) expense. Derivative instruments Chubb recognizes all derivatives at fair value in the Consolidated balance sheets in either Accounts payable, accrued expenses, and other liabilities or Other assets. Changes in fair value are included in Net realized gains (losses) in the Consolidated statements of operations. We did not designate any derivatives as accounting hedges. We participate in derivative instruments in two principal ways: (i) To sell protection to customers as an insurance or reinsurance contract that meets the definition of a derivative for accounting purposes. This category principally comprised our GLB contracts; and (ii) To mitigate financial risks and manage certain investment portfolio risks and exposures, including assets and liabilities held in foreign currencies. We use derivative instruments including futures, options, swaps, and foreign currency forward contracts. Refer to Note 10 for additional information. Securities lending program Chubb participates in a securities lending program operated by a third-party banking institution whereby certain assets are loaned to qualified borrowers and from which we earn an incremental return which is recorded within Net investment income in the Consolidated statement of operations. Borrowers provide collateral, in the form of either cash or approved securities, at a minimum of 102 percent of the fair value of the loaned securities. Each security loan is deemed to be an overnight transaction. Cash collateral is invested in a collateral pool which is managed by the banking institution. The collateral pool is subject to written investment guidelines with key objectives which include the safeguard of principal and adequate liquidity to meet anticipated redemptions. The fair value of the loaned securities is monitored on a daily basis, with additional collateral obtained or refunded as the fair value of the loaned securities changes. The collateral is held by the third-party banking institution, and the collateral can only be accessed in the event that the institution borrowing the securities is in default under the lending agreement. As a result of these restrictions, we consider our securities lending activities to be non-cash investing and financing activities. An indemnification agreement with the lending agent protects us in the event a borrower becomes insolvent or fails to return any of the securities on loan. The fair value of the securities on loan is included in fixed maturities and equity securities in the Consolidated balance sheets. The securities lending collateral is reported as a separate line in the Consolidated balance sheets with a related liability reflecting our obligation to return the collateral plus interest. Repurchase agreements Similar to securities lending arrangements, securities sold under repurchase agreements, whereby Chubb sells securities and repurchases them at a future date for a predetermined price, are accounted for as collateralized investments and borrowings and are recorded at the contractual repurchase amounts plus accrued interest. Assets to be repurchased are the same or substantially the same as the assets transferred, and the transferor, through right of substitution, maintains the right and ability to redeem the collateral on short notice. The fair value of the underlying securities is included in fixed maturities and equity securities. In contrast to securities lending programs, the use of cash received is not restricted. We report the obligation to return the cash as Repurchase agreements in the Consolidated balance sheets and record the fees under these repurchase agreements within Interest expense on the Consolidated statement of operations. Refer to Note 4 for a discussion on the determination of fair value for Chubb's various investment securities.
Cash	Cash We have agreements with a third-party bank provider which implemented two international multi-currency notional cash pooling programs. In each program, participating Chubb entities establish deposit accounts in different currencies with the bank provider and each day the credit or debit balances in every account are notionally translated into a single currency (U.S. dollars) and then notionally pooled. The bank extends overdraft credit to any participating Chubb entity as needed, provided that the overall notionally-pooled balance of all accounts in each pool at the end of each day is at least zero. Actual cash balances are not physically converted and are not commingled between legal entities. Any overdraft balances incurred under this program by a Chubb entity would be guaranteed by Chubb Limited (up to $300 million in the aggregate). Our syndicated letter of credit facility allows for same day drawings to fund a net pool overdraft should participating Chubb entities overdraw contributed funds from the pool. Restricted cash Restricted cash in the Consolidated balance sheets represents amounts held for the benefit of third parties and is legally or contractually restricted as to withdrawal or usage. Amounts include deposits with U.S. and non-U.S. regulatory authorities, trust funds set up for the benefit of ceding companies, and amounts pledged as collateral to meet financing arrangements.
Goodwill and other intangible assets	Goodwill and Other intangible assets Goodwill represents the excess of the cost of acquisitions over the fair value of net assets acquired and is not amortized. Goodwill is assigned at acquisition to the applicable reporting unit of the acquired entities giving rise to the goodwill. Goodwill impairment tests are performed annually or more frequently if circumstances indicate a possible impairment. For goodwill impairment testing, we use a qualitative assessment to determine whether it is more likely than not (i.e., more than a 50 percent probability) that the fair value of a reporting unit is greater than its carrying amount. If our assessment indicates less than a 50 percent probability that fair value exceeds carrying value, we quantitatively estimate a reporting unit's fair value. Goodwill recorded in connection with investments in partially-owned insurance companies is recorded in Investments in partially-owned insurance companies and is also measured for impairment annually. Indefinite lived intangible assets are not subject to amortization. Finite lived intangible assets are amortized over their useful lives, generally with an average original useful life of 25 years. Intangible assets are regularly reviewed for indicators of impairment. Impairment is recognized if the carrying amount is not recoverable from its undiscounted cash flows and is measured as the difference between the carrying amount and fair value.
Unpaid losses and loss expenses	Unpaid losses and loss expensesA liability is established for the estimated unpaid losses and loss expenses under the terms of, and with respect to, Chubb's policies and agreements. Similar to premiums that are recognized as revenues over the coverage period of the policy, a liability for unpaid losses and loss expenses is recognized as expense when insured events occur over the coverage period of the policy. This liability includes a provision for both reported claims (case reserves) and incurred but not reported claims (IBNR reserves). IBNR reserve estimates are generally calculated by first projecting the ultimate cost of all losses that have occurred (expected losses), and then subtracting paid losses, case reserves, and loss expenses. The methods of determining such estimates and establishing the resulting liability are reviewed regularly and any adjustments are reflected in income in the period in which they become known. Future developments may result in losses and loss expenses materially greater or less than recorded amounts. Except for net unpaid loss and loss expense reserves of $26 million, net of discount, held at December 31, 2020, representing certain structured settlements for which the timing and amount of future claim payments are reliably determinable and $42 million, net of discount, of certain reserves for unsettled claims, Chubb does not discount its P&C loss reserves. This compares with reserves of $31 million for certain structured settlements and $43 million of certain reserves for unsettled claims at December 31, 2019. Structured settlements represent contracts purchased from life insurance companies primarily to settle workers' compensation claims, where payments to the claimant by the life insurance company are expected to be made in the form of an annuity. Chubb retains the liability to the claimant in the event that the life insurance company fails to pay. At December 31, 2020, the liability due to claimants was $548 million, net of discount, and reinsurance recoverables due from the life insurance companies was $522 million, net of discount. For structured settlement contracts where payments are guaranteed regardless of claimant life expectancy, the amounts recoverable from the life insurance companies at December 31, 2020 are included in Other assets in the Consolidated balance sheets, as they do not meet the requirements for reinsurance accounting. Included in Unpaid losses and loss expenses are liabilities for asbestos and environmental (A&E) claims and expenses. These unpaid losses and loss expenses are principally related to claims arising from remediation costs associated with hazardous waste sites and bodily-injury claims related to asbestos products and environmental hazards. The estimation of these liabilities is particularly sensitive to changes in the legal environment including specific settlements that may be used as precedents to settle future claims. However, Chubb does not anticipate future changes in laws and regulations in setting its A&E reserve levels. Also included in Unpaid losses and loss expenses is the fair value adjustment of $110 million and $145 million at December 31, 2020 and 2019, respectively, related to Chubb Corp’s historical unpaid losses and loss expenses. The estimated fair value consists of the present value of the expected net unpaid loss and loss adjustment expense payments adjusted for an estimated risk margin. The estimated cash flows are discounted at a risk free rate. The estimated risk margin varies based on the inherent risks associated with each type of reserve. The fair value is amortized through Amortization of purchased intangibles on the consolidated statements of operations through the year 2032, based on the estimated payout patterns of unpaid loss and loss expenses at the acquisition date. Our loss reserves are presented net of contractual deductible recoverable amounts due from policyholders. Under the terms of certain high deductible policies which we offer, such as workers’ compensation and general liability, our customers are responsible to reimburse us for an agreed-upon dollar amount per claim. In nearly all cases we are required under such policies to pay covered claims first, and then seek reimbursement for amounts within the applicable deductible from our customers. We generally seek to mitigate this risk through collateral agreements. Prior period development arises from changes to loss estimates recognized in the current year that relate to loss reserves first reported in previous calendar years and excludes the effect of losses from the development of earned premiums from previous accident years. For purposes of analysis and disclosure, management views prior period development to be changes in the nominal value of loss estimates from period to period, net of premium and profit commission adjustments on loss sensitive contracts. Prior period development generally excludes changes in loss estimates that do not arise from the emergence of claims, such as those related to uncollectible reinsurance, interest, unallocated loss adjustment expenses, or foreign currency. Accordingly, specific items excluded from prior period development include the following: gains/losses related to foreign currency remeasurement; losses recognized from the early termination or commutation of reinsurance agreements that principally relate to the time value of money; changes in the value of reinsurance business assumed reflected in losses incurred but principally related to the time value of money; and losses that arise from changes in estimates of earned premiums from prior accident years. Except for foreign currency remeasurement, which is included in Net realized gains (losses), these items are included in current year losses.
Future policy benefits	Future policy benefits The valuation of long-duration contract reserves requires management to make estimates and assumptions regarding expenses, mortality, persistency, and investment yields. Estimates are primarily based on historical experience and include a margin for adverse deviation. Interest rates used in calculating reserves range from less than 1.0 percent to 9.0 percent at December 31, 2020 compared to less than 1.0 percent to 11.0 percent at December 31, 2019. Actual results could differ materially from these estimates. Management monitors actual experience and where circumstances warrant, will revise assumptions and the related reserve estimates. Revisions are recorded in the period they are determined. Certain of our long-duration contracts are supported by assets that do not qualify for separate account reporting under GAAP. These assets are classified as non-qualified separate account assets and reported in Other investments and the offsetting liabilities are reported in Future policy benefits in the Consolidated balance sheets. Changes in the fair value of separate account assets that do not qualify for separate account reporting under GAAP are reported in Other income (expense) and the offsetting movements in the liabilities are included in Policy benefits in the Consolidated statements of operations.
Assumed reinsurance programs involving minimum benefit guarantees under annuity contracts	Assumed reinsurance programs involving minimum benefit guarantees under variable annuity contracts Chubb reinsures various death and living benefit guarantees associated with variable annuities issued primarily in the United States. We generally receive a monthly premium during the accumulation phase of the covered annuities (in-force) based on a percentage of either the underlying accumulated account values or the underlying accumulated guaranteed values. Depending on an annuitant's age, the accumulation phase can last many years. To limit our exposure under these programs, all reinsurance treaties include annual or aggregate claim limits and many include an aggregate deductible. The guarantees which are payable on death, referred to as guaranteed minimum death benefits (GMDB), principally cover shortfalls between accumulated account value at the time of an annuitant's death and either i) an annuitant's total deposits; ii) an annuitant's total deposits plus a minimum annual return; or iii) the highest accumulated account value attained at any policy anniversary date. In addition, a death benefit may be based on a formula specified in the variable annuity contract that uses a percentage of the growth of the underlying contract value. Liabilities for GMDBs are based on cumulative assessments or premiums to date multiplied by a benefit ratio that is determined by estimating the present value of benefit payments and related adjustment expenses divided by the present value of cumulative assessment or expected premiums during the contract period. Under reinsurance programs covering GLBs, we assume the risk of guaranteed minimum income benefits (GMIB) associated with variable annuity contracts. The GMIB risk is triggered if, at the time the contract holder elects to convert the accumulated account value to a periodic payment stream (annuitize), the accumulated account value is not sufficient to provide a guaranteed minimum level of monthly income. Our GLB reinsurance products meet the definition of a derivative for accounting purposes and are carried at fair value with changes in fair value recognized in Realized gains (losses) in the Consolidated statement of operations. Refer to Note 10 a) for additional information.
Deposit assets and liabilities	Deposit assets and liabilities Deposit assets arise from ceded reinsurance contracts purchased that do not transfer significant underwriting or timing risk. Deposit liabilities include reinsurance deposit liabilities and contract holder deposit funds. The reinsurance deposit liabilities arise from contracts sold for which there is not a significant transfer of risk. Contract holder deposit funds represent a liability for investment contracts sold that do not meet the definition of an insurance contract, and certain of these contracts are sold with a guaranteed rate of return. Under deposit accounting, consideration received or paid is recorded as a deposit asset or liability in the balance sheet as opposed to recording premiums and losses in the statement of operations. Interest income on deposit assets, representing the consideration received or to be received in excess of cash payments related to the deposit contract, is earned based on an effective yield calculation. The calculation of the effective yield is based on the amount and timing of actual cash flows at the balance sheet date and the estimated amount and timing of future cash flows. The effective yield is recalculated periodically to reflect revised estimates of cash flows. When a change in the actual or estimated cash flows occurs, the resulting change to the carrying amount of the deposit asset is reported as income or expense. Deposit assets of $107 million and $93 million at December 31, 2020 and 2019, respectively, are reflected in Other assets in the Consolidated balance sheets and the accretion of deposit assets related to interest pursuant to the effective yield calculation is reflected in Net investment income in the Consolidated statements of operations. Deposit liabilities include reinsurance deposit liabilities of $86 million and $88 million and contract holder deposit funds of $2.2 billion and $2.0 billion at December 31, 2020 and 2019, respectively. Deposit liabilities are reflected in Accounts payable, accrued expenses, and other liabilities in the Consolidated balance sheets. At contract inception, the deposit liability equals net cash received. An accretion rate is established based on actuarial estimates whereby the deposit liability is increased to the estimated amount payable over the contract term. The deposit accretion rate is the rate of return required to fund expected future payment obligations. We periodically reassess the estimated ultimate liability and related expected rate of return. Changes to the deposit liability are generally reflected through Interest expense to reflect the cumulative effect of the period the contract has been in force, and by an adjustment to the future accretion rate of the liability over the remaining estimated contract term. The liability for contract holder deposit funds equals accumulated policy account values, which consist of the deposit payments plus credited interest less withdrawals and amounts assessed through the end of the period.
Property, Plant and Equipment, Policy [Policy Text Block]	Property and EquipmentProperty and equipment used in operations are capitalized and carried at cost less accumulated depreciation and are reported within Other assets in the Consolidated balance sheets. At December 31, 2020, property and equipment totaled $2.0 billion, consisting principally of capitalized software costs of $1.3 billion incurred to develop or obtain computer software for internal use and company-owned facilities of $260 million. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets. For capitalized software, the estimated useful life is generally three to five years, but can be as long as 15 years and for company-owned facilities the estimated useful life is 40 years. At December 31, 2019, property and equipment totaled $1.9 billion.
Foreign currency remeasurement and translation	Foreign currency remeasurement and translationThe functional currency for each of our foreign operations is generally the currency of the local operating environment. Transactions in currencies other than a foreign operation's functional currency are remeasured into the functional currency, and the resulting foreign exchange gains and losses are reflected in Net realized gains (losses) in the Consolidated statements of operations. Functional currency assets and liabilities are translated into the reporting currency, U.S. dollars, using period end exchange rates and the related translation adjustments are recorded as a separate component of AOCI in Shareholders' equity. Functional statement of operations amounts expressed in functional currencies are translated using average exchange rates.
Administrative expenses	Administrative expensesAdministrative expenses generally include all operating costs other than policy acquisition costs. The North America Commercial P&C Insurance segment manages and uses an in-house third-party claims administrator, ESIS Inc. (ESIS). ESIS performs claims management and risk control services for domestic and international organizations that self-insure P&C exposures as well as internal P&C exposures. The net operating income of ESIS is included within Administrative expenses in the Consolidated statements of operations and were $18 million, $47 million, and $49 million for the years ended December 31, 2020, 2019, and 2018, respectively.
Income taxes	Income taxesIncome taxes have been recorded related to those operations subject to income tax. Deferred tax assets and liabilities result from temporary differences between the amounts recorded in the Consolidated Financial Statements and the tax basis of our assets and liabilities. The effect on deferred tax assets and liabilities of a change in tax law or rates is recognized in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if it is more likely than not that all, or some portion, of the benefits related to these deferred tax assets will not be realized. The valuation allowance assessment considers tax planning strategies, where appropriate.We recognize uncertain tax positions that are determined to be more likely than not of being sustained upon examination. Recognized income tax positions are measured at the largest amount that has a greater than 50 percent likelihood of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs.
Earnings per share	Earnings per shareBasic earnings per share is calculated using the weighted-average shares outstanding, including participating securities with non-forfeitable rights to dividends such as unvested restricted stock. All potentially dilutive securities, including stock options are excluded from the basic earnings per share calculation. In calculating diluted earnings per share, the weighted-average shares outstanding is increased to include all potentially dilutive securities. Basic and diluted earnings per share are calculated by dividing net income by the applicable weighted-average number of shares outstanding during the year.
Share-based compensation	Share-based compensationChubb measures and records compensation cost for all share-based payment awards at grant-date fair value. Compensation costs are recognized for vesting of share-based payment awards with only service conditions on a straight-line basis over the requisite service period for each separately vesting portion of the award as if the award were, in substance, multiple awards. For retirement-eligible participants, compensation costs for certain share-based payment awards are recognized immediately at the date of grant. Refer to Note 12 for additional information.
Chubb integration expenses	Chubb integration expensesDirect costs related to the Chubb Corp acquisition were expensed as incurred. Chubb integration expenses were nil, $23 million, and $59 million for the years ended December 31, 2020, 2019 and 2018, respectively, and include all internal and external costs directly related to the integration activities of the Chubb Corp acquisition. These expenses principally consisted of personnel-related expenses, consulting fees, and rebranding.
New accounting pronouncements	Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments Effective January 1, 2020, we adopted, on a modified retrospective basis, new guidance on the accounting for credit losses of financial instruments that are measured at amortized cost, including held to maturity securities, and reinsurance recoverables, by applying an approach based on the current expected credit losses (CECL). The estimate of expected credit losses considers historical information, current information, as well as reasonable and supportable forecasts, including estimates of prepayments. In addition, the guidance also replaced the current available for sale (AFS) security other-than-temporary impairment model by requiring an estimate of the expected credit loss (ECL) only when the fair value is below the amortized cost of the asset. The length of time the fair value of an AFS security has been below its amortized cost no longer impacts the determination of whether a potential credit loss exists. The AFS security model also requires the use of a valuation allowance as compared to the previous practice of writing down the asset. In 2020, we recognized a cumulative effect adjustment and decreased beginning retained earnings by $79 million pre-tax, or $72 million after-tax, principally related to the valuation allowance for credit losses. We also adopted the required disclosures within Note 3 Investments and Note 5 Reinsurance. Results for reporting periods prior to January 1, 2020 are presented in accordance with the previous guidance. Adopted in 2021 Income Taxes - Simplifying the Accounting for Income Taxes Effective January 1, 2021, we adopted guidance which is intended to simplify the accounting for income taxes by removing several exceptions contained in existing guidance and amending other guidance. The adoption of the new guidance did not have a material effect on our results of operations or financial condition. Accounting guidance not yet adopted Effects of Reference Rate Reform on Financial Reporting In March 2020, the FASB issued guidance which provides optional expedients and exceptions for applying GAAP to investments, derivatives, or other transactions that reference the London Interbank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of reference rate reform. Along with the optional expedients, the amendments include a general principle that permits an entity to consider contract modifications due to reference reform to be an event that does not require contract re-measurement at the modification date or reassessment of a previous accounting determination. Additionally, a company may make a one-time election to sell, transfer, or both sell and transfer debt securities classified as held to maturity that reference a rate affected by reference rate reform and that were classified as held to maturity before January 1, 2020. This standard may be elected over time through December 31, 2022 as reference rate reform activities occur. Our exposure to LIBOR is limited and, accordingly, we do not expect reference rate reform to have a material impact on our Consolidated Financial Statements. Targeted Improvements to the Accounting for Long-Duration Contracts In August 2018, the FASB issued guidance to improve the existing recognition, measurement, presentation, and disclosure requirements for long-duration contracts issued by an insurance entity. The amendments in this update require more frequent updating of assumptions and a standardized discount rate for the future policy benefit liability, a requirement to use the fair value measurement model for policies with market risk benefits, simplified amortization of deferred acquisition costs, and enhanced disclosures. This standard will be effective in the first quarter of 2023 with early adoption permitted. We are currently assessing the effect of adopting this guidance on our financial condition and results of operations. We will be better able to quantify the effect of adopting this standard as we progress in our implementation process and draw nearer to the date of adoption.

Summary of significant accounting policies Summary of Significant Accounting Policies (Tables) (Tables)

12 Months Ended

Dec. 31, 2020

Cash and Cash Equivalents [Abstract]

Schedule of Cash and Cash Equivalents [Table Text Block]

The following table provides a reconciliation of cash and restricted cash reported within the Consolidated balance sheets that total to the amounts shown in the Consolidated statements of cash flows:


	December 31
(in millions of U.S. dollars)	2020		2019		2018
Cash	$	1,747	$	1,537	$	1,247
Restricted cash	89		109		93
Total cash and restricted cash shown in the Consolidated statements of cash flows	$	1,836	$	1,646	$	1,340

Investments (Tables)

12 Months Ended

Dec. 31, 2020

Investments, Debt and Equity Securities [Abstract]

Debt securities Available for sale


December 31, 2020	Amortized Cost		Valuation Allowance		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	2,471	$	—	$	199	$	—	$	2,670
Non-U.S.	24,594		(6)		1,808		(42)		26,354
Corporate and asset-backed securities	34,095		(14)		2,322		(72)		36,331
Mortgage-backed securities	17,456		—		1,022		(8)		18,470
Municipal	6,572		—		304		(2)		6,874
	$	85,188	$	(20)	$	5,655	$	(124)	$	90,699
	Amortized Cost		Valuation Allowance		Net Carrying Value		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
Held to maturity
U.S. Treasury / Agency	$	1,392	$	—	$	1,392	$	60	$	—	$	1,452
Non-U.S.	1,295		(7)		1,288		118		(1)		1,405
Corporate and asset-backed securities	2,185		(35)		2,150		288		—		2,438
Mortgage-backed securities	2,000		(1)		1,999		148		(1)		2,146
Municipal	4,825		(1)		4,824		245		—		5,069
	$	11,697	$	(44)	$	11,653	$	859	$	(2)	$	12,510


December 31, 2019	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value		OTTI Recognized in AOCI
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	3,188	$	96	$	(1)	$	3,283	$	—
Non-U.S.	22,670		1,099		(62)		23,707		(25)
Corporate and asset-backed securities	30,689		1,180		(78)		31,791		(5)
Mortgage-backed securities	18,712		494		(14)		19,192		—
Municipal	7,321		205		(11)		7,515		—
	$	82,580	$	3,074	$	(166)	$	85,488	$	(30)
Held to maturity
U.S. Treasury / Agency	$	1,318	$	29	$	—	$	1,347	$	—
Non-U.S.	1,423		62		—		1,485		—
Corporate and asset-backed securities	2,349		121		(2)		2,468		—
Mortgage-backed securities	2,331		65		—		2,396		—
Municipal	5,160		150		(1)		5,309		—
	$	12,581	$	427	$	(3)	$	13,005	$	—

Debt Securities Held to Maturity


December 31, 2020	Amortized Cost		Valuation Allowance		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	2,471	$	—	$	199	$	—	$	2,670
Non-U.S.	24,594		(6)		1,808		(42)		26,354
Corporate and asset-backed securities	34,095		(14)		2,322		(72)		36,331
Mortgage-backed securities	17,456		—		1,022		(8)		18,470
Municipal	6,572		—		304		(2)		6,874
	$	85,188	$	(20)	$	5,655	$	(124)	$	90,699
	Amortized Cost		Valuation Allowance		Net Carrying Value		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
Held to maturity
U.S. Treasury / Agency	$	1,392	$	—	$	1,392	$	60	$	—	$	1,452
Non-U.S.	1,295		(7)		1,288		118		(1)		1,405
Corporate and asset-backed securities	2,185		(35)		2,150		288		—		2,438
Mortgage-backed securities	2,000		(1)		1,999		148		(1)		2,146
Municipal	4,825		(1)		4,824		245		—		5,069
	$	11,697	$	(44)	$	11,653	$	859	$	(2)	$	12,510


December 31, 2019	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value		OTTI Recognized in AOCI
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	3,188	$	96	$	(1)	$	3,283	$	—
Non-U.S.	22,670		1,099		(62)		23,707		(25)
Corporate and asset-backed securities	30,689		1,180		(78)		31,791		(5)
Mortgage-backed securities	18,712		494		(14)		19,192		—
Municipal	7,321		205		(11)		7,515		—
	$	82,580	$	3,074	$	(166)	$	85,488	$	(30)
Held to maturity
U.S. Treasury / Agency	$	1,318	$	29	$	—	$	1,347	$	—
Non-U.S.	1,423		62		—		1,485		—
Corporate and asset-backed securities	2,349		121		(2)		2,468		—
Mortgage-backed securities	2,331		65		—		2,396		—
Municipal	5,160		150		(1)		5,309		—
	$	12,581	$	427	$	(3)	$	13,005	$	—

Debt Securities, Held-to-maturity, Credit Quality Indicator

The following table presents the amortized cost of our HTM securities according to S&P rating:


December 31, 2020
(in millions of U.S. dollars)	Amortized cost		% of Total
AAA	$	2,511	22	%
AA	6,193		53	%
A	2,138		18	%
BBB	826		7	%
BB	28		—	%
Other	1		—	%
Total	$	11,697	100	%

Schedule Of Fixed Maturities By Contractual Maturity

The following table presents fixed maturities by contractual maturity:


	December 31				December 31
			2020				2019
(in millions of U.S. dollars)	Net Carrying Value		Fair Value		Amortized Cost		Fair Value
Available for sale
Due in 1 year or less	$	4,760	$	4,760	$	3,951	$	3,973
Due after 1 year through 5 years	26,227		26,227		27,142		27,720
Due after 5 years through 10 years	27,232		27,232		23,901		24,874
Due after 10 years	14,010		14,010		8,874		9,729
	72,229		72,229		63,868		66,296
Mortgage-backed securities	18,470		18,470		18,712		19,192
	$	90,699	$	90,699	$	82,580	$	85,488
Held to maturity
Due in 1 year or less	$	1,231	$	1,240	$	478	$	479
Due after 1 year through 5 years	3,592		3,760		3,869		3,940
Due after 5 years through 10 years	3,029		3,228		3,756		3,883
Due after 10 years	1,802		2,136		2,147		2,307
	9,654		10,364		10,250		10,609
Mortgage-backed securities	1,999		2,146		2,331		2,396
	$	11,653	$	12,510	$	12,581	$	13,005

Schedule Of Aggregate Fair Value And Gross Unrealized Loss By Length Of Time The Security Has Continuously Been In An Unrealized Loss Position

The following table presents, for AFS fixed maturities in an unrealized loss position (including securities on loan) that are not deemed to have credit losses, the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position:


	0 – 12 Months				Over 12 Months				Total
December 31, 2020	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)

Non-U.S.	$	1,628	$	(35)	$	114	$	(5)	$	1,742	$	(40)
Corporate and asset-backed securities	2,212		(33)		593		(14)		2,805		(47)
Mortgage-backed securities	875		(6)		35		(2)		910		(8)
Municipal	40		(1)		16		(1)		56		(2)
Total AFS fixed maturities	$	4,755	$	(75)	$	758	$	(22)	$	5,513	$	(97)

The following table presents, for all securities in an unrealized loss position (including securities on loan), the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position:


	0 – 12 Months				Over 12 Months				Total
December 31, 2019	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)
U.S. Treasury / Agency	$	234	$	(1)	$	339	$	—	$	573	$	(1)
Non-U.S.	1,846		(34)		802		(28)		2,648		(62)
Corporate and asset-backed securities	2,121		(40)		988		(40)		3,109		(80)
Mortgage-backed securities	1,174		(6)		932		(8)		2,106		(14)
Municipal	188		—		276		(12)		464		(12)
Total fixed maturities	$	5,563	$	(81)	$	3,337	$	(88)	$	8,900	$	(169)

Schedule Of Net Realized Gains (Losses) And The Losses Included In Net Realized Gains (Losses) And OCI

The following table presents the components of Net realized gains (losses) and the change in net unrealized appreciation (depreciation) of investments:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Fixed maturities:
OTTI on fixed maturities, gross	$	—	$	(90)	$	(52)
OTTI on fixed maturities recognized in OCI (pre-tax)	—		32		3
OTTI on fixed maturities, net	—		(58)		(49)
Gross realized gains excluding OTTI	244		203		334
Gross realized losses excluding OTTI	(366)		(176)		(587)
Recovery of expected credit losses	11		—		—
Impairment (1)	(170)		—		—
Total fixed maturities	(281)		(31)		(302)
Equity securities	586		104		(59)

Other investments	(32)		(20)		(5)
Foreign exchange gains (losses)	(483)		7		131
Investment and embedded derivative instruments	81		(435)		(75)
Fair value adjustments on insurance derivative	(202)		(4)		(248)
S&P futures	(108)		(138)		(4)
Other derivative instruments	1		(8)		(3)
Other	(60)		(5)		(87)
Net realized gains (losses) (pre-tax)	$	(498)	$	(530)	$	(652)

Change in net unrealized appreciation (depreciation) on investments (pre-tax):
Fixed maturities available for sale	$	2,628	$	3,769	$	(1,958)
Fixed maturities held to maturity	(24)		(31)		(38)

Other	(12)		(3)		—
Income tax (expense) benefit	(462)		(647)		297
Change in net unrealized appreciation (depreciation) on investments (after-tax)	$	2,130	$	3,088	$	(1,699)

Gain (Loss) on Securities [Table Text Block]

Realized gains and losses from Equity securities and Other investments from the table above include sales of securities and unrealized gains and losses from fair value changes as follows:


	Year Ended December 31, 2020						Year Ended December 31, 2019						Year Ended December 31, 2018
(in millions of U.S. dollars)	Equity Securities		Other Investments		Total		Equity Securities		Other Investments		Total		Equity Securities		Other Investments		Total
Net gains (losses) recognized during the period	$	586	$	(32)	$	554	$	104	$	(20)	$	84	$	(59)	$	(5)	$	(64)
Less: Net gains (losses) recognized from sales of securities	455		—		455		58		(5)		53		70		121		191
Unrealized gains (losses) recognized for securities still held at reporting date	$	131	$	(32)	$	99	$	46	$	(15)	$	31	$	(129)	$	(126)	$	(255)

Debt Securities, Available-for-sale, Allowance for Credit Loss

The following table presents a roll-forward of valuation allowance for expected credit losses on fixed maturities:


	Year Ended
	December 31
(in millions of U.S. dollars)	2020
Available for sale
Valuation allowance for expected credit losses - beginning of period	$	—
Impact of adoption of new accounting guidance	25
Provision for expected credit loss	188
Initial allowance for purchased securities with credit deterioration	5
Write-offs charged against the expected credit loss	(5)
Recovery of expected credit loss	(193)
Valuation allowance for expected credit losses - end of period	$	20
Held to maturity
Valuation allowance for expected credit losses - beginning of period	$	—
Impact of adoption of new accounting guidance	44
Provision for expected credit loss	9


Recovery of expected credit loss	(9)
Valuation allowance for expected credit losses - end of period	$	44

Debt Securities, Held-to-maturity, Allowance for Credit Loss

The following table presents a roll-forward of valuation allowance for expected credit losses on fixed maturities:


	Year Ended
	December 31
(in millions of U.S. dollars)	2020
Available for sale
Valuation allowance for expected credit losses - beginning of period	$	—
Impact of adoption of new accounting guidance	25
Provision for expected credit loss	188
Initial allowance for purchased securities with credit deterioration	5
Write-offs charged against the expected credit loss	(5)
Recovery of expected credit loss	(193)
Valuation allowance for expected credit losses - end of period	$	20
Held to maturity
Valuation allowance for expected credit losses - beginning of period	$	—
Impact of adoption of new accounting guidance	44
Provision for expected credit loss	9


Recovery of expected credit loss	(9)
Valuation allowance for expected credit losses - end of period	$	44

Schedule Of Other Investments


	December 31
(in millions of U.S. dollars)	2020		2019
Alternative investments:
Partially-owned investment companies	$	5,969	$	4,142
Limited partnerships	547		508
Investment funds	254		271
Alternative investments	6,770		4,921
Life insurance policies	438		377
Policy loans	233		247
Non-qualified separate account assets (1)	316		283
Other	188		234
Total	$	7,945	$	6,062

Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table Text Block]

The following table presents, by investment category, the expected liquidation period, fair value, and maximum future funding commitments of alternative investments:


		December 31				December 31
		2020				2019
(in millions of U.S. dollars)	Expected Liquidation Period of Underlying Assets	Fair Value		Maximum Future Funding Commitments		Fair Value		Maximum Future Funding Commitments
Financial	2 to 10 Years	$	673	$	237	$	611	$	329
Real Assets	2 to 11 Years	805		598		712		422
Distressed	2 to 8 Years	358		970		263		80
Private Credit	3 to 8 Years	88		270		104		272
Traditional	2 to 14 Years	4,519		1,125		2,844		2,160
Vintage	1 to 2 Years	73		—		116		—
Investment funds	Not Applicable	254		—		271		—
		$	6,770	$	3,200	$	4,921	$	3,263

Schedule Of Sources Of Net Investment Income


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Fixed maturities (1)	$	3,321	$	3,385	$	3,128
Short-term investments	48		84		90
Other interest income	19		25		118
Equity securities	81		26		33
Other investments	82		78		104
Gross investment income (1)	3,551		3,598		3,473
Investment expenses	(176)		(172)		(168)
Net investment income (1)	$	3,375	$	3,426	$	3,305
(1) Includes amortization expense related to fair value adjustment of acquired invested assets related to the Chubb Corp acquisition	$	(116)	$	(161)	$	(248)

Schedule Of Components Of Restricted Assets

The following table presents the components of restricted assets:


	December 31		December 31
(in millions of U.S. dollars)	2020		2019
Trust funds	$	12,305	$	14,004
Deposits with U.S. regulatory authorities	2,438		2,466
Deposits with non-U.S. regulatory authorities	2,905		2,709
Assets pledged under repurchase agreements	1,462		1,464
Other pledged assets	584		490
Total	$	19,694	$	21,133

Fair value measurements (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Schedule Of Significant Unobservable Inputs Used In Level 3 Liability Valuations

The following table presents the significant unobservable inputs used in the Level 3 liability valuations. Excluded from the table below are inputs used to determine the fair value of Level 3 assets which are based on single broker quotes and contain no quantitative unobservable inputs developed by management. The majority of our fixed maturities classified as Level 3 used external pricing when markets are less liquid due to the lack of market inputs (i.e., stale pricing, broker quotes).


(in millions of U.S. dollars, except for percentages)	Fair Value at December 31 2020		Valuation Technique	Significant Unobservable Inputs	Ranges	Weighted Average (1)
GLB (1)	$	1,089	Actuarial model	Lapse rate	3% - 34%	4.7	%
				Annuitization rate	0% - 100%	3.6	%

(1)The weighted average lapse and annuitization rates are determined by weighting each treaty's rates by the GLB contracts fair value.

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation

The following tables present a reconciliation of the beginning and ending balances of financial instruments measured at fair value using significant unobservable inputs (Level 3):


											Assets		Liabilities
	Available-for-Sale Debt Securities						Equity securities		Short-term investments		Other investments		GLB (1)
Year Ended December 31, 2020	Non-U.S.		Corporate and asset-backed securities		MBS
(in millions of U.S. dollars)
Balance, beginning of year	$	449	$	1,451	$	60	$	69	$	6	$	10	$	897
Transfers into Level 3	—		134		—		—		—		—		—
Transfers out of Level 3	(16)		(73)		(1)		(3)		—		—		—
Change in Net Unrealized Gains/Losses in OCI	19		(8)		—		—		—		—		—
Net Realized Gains/Losses	(1)		(30)		—		1		(1)		—		202
Purchases	274		708		2		23		14		—		—
Sales	(122)		(186)		—		(17)		(2)		—		—
Settlements	(57)		(423)		(1)		—		(12)		—		—
Other	—		—		—		—		—		—		(10)
Balance, end of year	$	546	$	1,573	$	60	$	73	$	5	$	10	$	1,089
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—	$	(5)	$	—	$	4	$	—	$	—	$	202
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date	$	16	$	(6)	$	—	$	—	$	—	$	—	$	—

(1)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.


	Assets												Liabilities
	Available-for-Sale Debt Securities						Equity securities		Short-term investments		Other investments		GLB (1)
Year Ended December 31, 2019	Non-U.S.		Corporate and asset-backed securities		MBS
(in millions of U.S. dollars)
Balance, beginning of year	$	345	$	1,299	$	61	$	57	$	1	$	11	$	861
Transfers into Level 3	11		23		—		—		—		—		—
Transfers out of Level 3	(24)		(38)		(16)		—		—		—		—
Change in Net Unrealized Gains/Losses in OCI	13		(2)		—		1		—		—		—
Net Realized Gains/Losses	(1)		(4)		—		(2)		—		—		4
Purchases	228		577		19		34		6		—		—
Sales	(70)		(125)		(1)		(21)		—		—		—
Settlements	(53)		(279)		(3)		—		(1)		(1)		—
Other	—		—		—		—		—		—		32
Balance, end of year	$	449	$	1,451	$	60	$	69	$	6	$	10	$	897
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—	$	(2)	$	—	$	(3)	$	—	$	—	$	4
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date	$	7	$	(8)	$	—	$	—	$	—	$	—	$	—

(1)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.


	Assets												Liabilities
	Available-for-Sale Debt Securities								Short-term investments				Other derivative instruments		GLB (1)
Year Ended December 31, 2018	Non-U.S.		Corporate and asset-backed securities		MBS		Equity securities				Other investments
(in millions of U.S. dollars)
Balance, beginning of year	$	93	$	1,037	$	78	$	44	$	—	$	263	$	2	$	550
Transfers into Level 3	13		24		1		—		5		—		—		—
Transfers out of Level 3	(2)		(31)		(3)		—		—		(252)		—		—
Change in Net Unrealized Gains/Losses in OCI	(12)		(4)		—		(2)		—		(2)		—		—
Net Realized Gains/Losses	(3)		(5)		—		6		—		1		(2)		248
Purchases	334		672		5		37		9		50		—		—
Sales	(69)		(164)		—		(28)		—		—		—		—
Settlements	(9)		(230)		(20)		—		(13)		(49)		—		—
Other	—		—		—		—		—		—		—		63
Balance, end of year	$	345	$	1,299	$	61	$	57	$	1	$	11	$	—	$	861
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	(1)	$	(7)	$	—	$	(1)	$	—	$	1	$	—	$	248

(1)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]


											Assets		Liabilities
	Available-for-Sale Debt Securities						Equity securities		Short-term investments		Other investments		GLB (1)
Year Ended December 31, 2020	Non-U.S.		Corporate and asset-backed securities		MBS
(in millions of U.S. dollars)
Balance, beginning of year	$	449	$	1,451	$	60	$	69	$	6	$	10	$	897
Transfers into Level 3	—		134		—		—		—		—		—
Transfers out of Level 3	(16)		(73)		(1)		(3)		—		—		—
Change in Net Unrealized Gains/Losses in OCI	19		(8)		—		—		—		—		—
Net Realized Gains/Losses	(1)		(30)		—		1		(1)		—		202
Purchases	274		708		2		23		14		—		—
Sales	(122)		(186)		—		(17)		(2)		—		—
Settlements	(57)		(423)		(1)		—		(12)		—		—
Other	—		—		—		—		—		—		(10)
Balance, end of year	$	546	$	1,573	$	60	$	73	$	5	$	10	$	1,089
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—	$	(5)	$	—	$	4	$	—	$	—	$	202
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date	$	16	$	(6)	$	—	$	—	$	—	$	—	$	—

(1)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.


	Assets												Liabilities
	Available-for-Sale Debt Securities						Equity securities		Short-term investments		Other investments		GLB (1)
Year Ended December 31, 2019	Non-U.S.		Corporate and asset-backed securities		MBS
(in millions of U.S. dollars)
Balance, beginning of year	$	345	$	1,299	$	61	$	57	$	1	$	11	$	861
Transfers into Level 3	11		23		—		—		—		—		—
Transfers out of Level 3	(24)		(38)		(16)		—		—		—		—
Change in Net Unrealized Gains/Losses in OCI	13		(2)		—		1		—		—		—
Net Realized Gains/Losses	(1)		(4)		—		(2)		—		—		4
Purchases	228		577		19		34		6		—		—
Sales	(70)		(125)		(1)		(21)		—		—		—
Settlements	(53)		(279)		(3)		—		(1)		(1)		—
Other	—		—		—		—		—		—		32
Balance, end of year	$	449	$	1,451	$	60	$	69	$	6	$	10	$	897
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—	$	(2)	$	—	$	(3)	$	—	$	—	$	4
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date	$	7	$	(8)	$	—	$	—	$	—	$	—	$	—

(1)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.


	Assets												Liabilities
	Available-for-Sale Debt Securities								Short-term investments				Other derivative instruments		GLB (1)
Year Ended December 31, 2018	Non-U.S.		Corporate and asset-backed securities		MBS		Equity securities				Other investments
(in millions of U.S. dollars)
Balance, beginning of year	$	93	$	1,037	$	78	$	44	$	—	$	263	$	2	$	550
Transfers into Level 3	13		24		1		—		5		—		—		—
Transfers out of Level 3	(2)		(31)		(3)		—		—		(252)		—		—
Change in Net Unrealized Gains/Losses in OCI	(12)		(4)		—		(2)		—		(2)		—		—
Net Realized Gains/Losses	(3)		(5)		—		6		—		1		(2)		248
Purchases	334		672		5		37		9		50		—		—
Sales	(69)		(164)		—		(28)		—		—		—		—
Settlements	(9)		(230)		(20)		—		(13)		(49)		—		—
Other	—		—		—		—		—		—		—		63
Balance, end of year	$	345	$	1,299	$	61	$	57	$	1	$	11	$	—	$	861
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	(1)	$	(7)	$	—	$	(1)	$	—	$	1	$	—	$	248

(1)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

Carrying Values And Fair Values Of Financial Instruments Not Measured At Fair Value


December 31, 2020	Fair Value								Net Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities held to maturity
U.S. Treasury / Agency	$	1,395	$	57	$	—	$	1,452	$	1,392
Non-U.S.	—		1,405		—		1,405		1,288
Corporate and asset-backed securities	—		2,438		—		2,438		2,150
Mortgage-backed securities	—		2,146		—		2,146		1,999
Municipal	—		5,069		—		5,069		4,824
Total assets	$	1,395	$	11,115	$	—	$	12,510	$	11,653
Liabilities:
Repurchase agreements	$	—	$	1,405	$	—	$	1,405	$	1,405
Short-term debt	—		—		—		—		—
Long-term debt	—		17,487		—		17,487		14,948
Trust preferred securities	—		473		—		473		308
Total liabilities	$	—	$	19,365	$	—	$	19,365	$	16,661


December 31, 2019	Fair Value								Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities held to maturity
U.S. Treasury / Agency	$	1,292	$	55	$	—	$	1,347	$	1,318
Non-U.S.	—		1,485		—		1,485		1,423
Corporate and asset-backed securities	—		2,436		32		2,468		2,349
Mortgage-backed securities	—		2,396		—		2,396		2,331
Municipal	—		5,309		—		5,309		5,160
Total assets	$	1,292	$	11,681	$	32	$	13,005	$	12,581
Liabilities:
Repurchase agreements	$	—	$	1,416	$	—	$	1,416	$	1,416
Short-term debt	—		1,307		—		1,307		1,299
Long-term debt	—		15,048		—		15,048		13,559
Trust preferred securities	—		467		—		467		308
Total liabilities	$	—	$	18,238	$	—	$	18,238	$	16,582

Reinsurance (Tables)

12 Months Ended

Dec. 31, 2020

Reinsurance Disclosures [Abstract]

Schedule of direct, assumed and ceded premiums

The following table presents direct, assumed, and ceded premiums:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Premiums written
Direct	$	37,749	$	36,848	$	34,782
Assumed	3,512		3,276		3,186
Ceded	(7,441)		(7,849)		(7,389)
Net	$	33,820	$	32,275	$	30,579
Premiums earned
Direct	$	37,037	$	35,876	$	34,108
Assumed	3,323		3,107		3,175
Ceded	(7,243)		(7,693)		(7,219)
Net	$	33,117	$	31,290	$	30,064

Schedule of Reinsurance Recoverable on Ceded Insurance [Table Text Block]

b) Reinsurance recoverable on ceded reinsurance


	December 31, 2020				December 31, 2019
(in millions of U.S. dollars)	Net Reinsurance Recoverable (1)		Valuation allowance		Net Reinsurance Recoverable (1)		Valuation allowance
Reinsurance recoverable on unpaid losses and loss expenses	$	14,647	$	257	$	14,181	$	240
Reinsurance recoverable on paid losses and loss expenses	945		57		1,000		76
Reinsurance recoverable on losses and loss expenses	$	15,592	$	314	$	15,181	$	316
Reinsurance recoverable on policy benefits	$	206	$	5	$	197	$	4

Reinsurance Recoverable, Allowance for Credit Loss

The following table presents a roll-forward of valuation allowance for uncollectible reinsurance related to Reinsurance recoverable on loss and loss expenses:


(in millions of U.S. dollars)	Year Ended December 31, 2020
Valuation allowance for uncollectible reinsurance - beginning of period	$	316
Provision for uncollectible reinsurance	21
Write-offs charged against the valuation allowance	(25)
Foreign exchange revaluation	2
Valuation allowance for uncollectible reinsurance - end of period	$	314

Schedule of reinsurance recoverable and provision by category of reinsurer


December 31, 2020	Gross Reinsurance Recoverable on Loss and Loss Expenses		Valuation allowance for Uncollectible Reinsurance		% of Gross Reinsurance Recoverable
(in millions of U.S. dollars, except for percentages)
Categories
Largest reinsurers	$	7,267	$	88	1.2	%
Other reinsurers rated A- or better	4,901		58		1.2	%
Other reinsurers rated lower than A- or not rated	466		64		13.7	%
Pools	366		14		3.8	%
Structured settlements	521		11		2.1	%
Captives	2,107		11		0.5	%
Other	278		68		24.5	%
Total	$	15,906	$	314	2.0	%

Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill roll-forward by business segment

The following table presents a roll-forward of Goodwill by segment:


(in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Chubb Consolidated
Balance at December 31, 2018	$	6,946	$	2,230	$	134	$	4,770	$	371	$	820	$	15,271
Foreign exchange revaluation and other	9		4		—		15		—		(3)		25
Balance at December 31, 2019	$	6,955	$	2,234	$	134	$	4,785	$	371	$	817	$	15,296
Acquisition of Banchile Seguros de Vida	—		—		—		16		—		28		44
Foreign exchange revaluation and other	17		6		—		35		—		2		60
Balance at December 31, 2020	$	6,972	$	2,240	$	134	$	4,836	$	371	$	847	$	15,400

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]


	Associated with the Chubb Corp Acquisition
For the Years Ending December 31 (in millions of U.S. dollars)	Agency distribution relationships and renewal rights		Fair value adjustment on Unpaid losses and loss expense (1)		Total		Other intangible assets		Total Amortization of purchased intangibles
2021	$	217	$	(20)	$	197	$	89	$	286
2022	197		(14)		183		101		284
2023	178		(7)		171		96		267
2024	160		(6)		154		90		244
2025	145		(6)		139		89		228
Total	$	897	$	(53)	$	844	$	465	$	1,309

(1)In connection with the Chubb Corp acquisition, we recorded an increase to Unpaid losses and loss expenses acquired to adjust the carrying value of Chubb Corp's historical Unpaid losses and loss expenses to fair value as of the acquisition date. This fair value adjustment amortizes through Amortization of purchased intangibles on the Consolidated statements of operations through the year 2032. The balance of the fair value adjustment on Unpaid losses and loss expense was $110 million and $145 million at December 31, 2020 and 2019, respectively. Refer to Note 1(h) for additional information.

VOBA

The following table presents a roll-forward of VOBA:


(in millions of U.S. dollars)	2020		2019		2018
Balance, beginning of year	$	306	$	295	$	326
Amortization of VOBA (1)	(27)		(24)		(25)
Foreign exchange revaluation and other	(16)		35		(6)
Balance, end of year	$	263	$	306	$	295

(1)Recognized in Policy acquisition costs in the Consolidated statements of operations.

The following table presents, as of December 31, 2020, the expected estimated pre-tax amortization expense related to VOBA for the next five years at current foreign exchange rates:


For the Years Ending December 31	VOBA
(in millions of U.S. dollars)
2021	$	22
2022	21
2023	19
2024	17
2025	16
Total	$	95

Unpaid losses and loss expenses (Tables)

12 Months Ended

Dec. 31, 2020

Liability for Claims and Claims Adjustment Expense [Abstract]

Schedule Of Unpaid Losses And Loss Expenses Roll Forward

Chubb establishes reserves for the estimated unpaid ultimate liability for losses and loss expenses under the terms of its policies and agreements. Reserves include estimates for both claims that have been reported and for IBNR claims, and include estimates of expenses associated with processing and settling these claims. Reserves are recorded in Unpaid losses and loss expenses in the consolidated balance sheets. While we believe that our reserves for unpaid losses and loss expenses at December 31, 2020 are adequate, new information or trends may lead to future developments in incurred loss and loss expenses significantly greater or less than the reserves provided. Any such revisions could result in future changes in estimates of losses or reinsurance recoverable and would be reflected in our results of operations in the period in which the estimates are changed.

The following table presents a reconciliation of beginning and ending Unpaid losses and loss expenses:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Gross unpaid losses and loss expenses, beginning of year	$	62,690	$	62,960	$	63,179
Reinsurance recoverable on unpaid losses (1)	(14,181)		(14,689)		(14,014)
Net unpaid losses and loss expenses, beginning of year	48,509		48,271		49,165


Net losses and loss expenses incurred in respect of losses occurring in:
Current year	22,124		19,575		19,048
Prior years (2)	(414)		(845)		(981)
Total	21,710		18,730		18,067
Net losses and loss expenses paid in respect of losses occurring in:
Current year	7,782		7,894		7,544
Prior years	9,652		10,579		10,796
Total	17,434		18,473		18,340
Foreign currency revaluation and other	379		(19)		(621)
Net unpaid losses and loss expenses, end of year	53,164		48,509		48,271
Reinsurance recoverable on unpaid losses (1)	14,647		14,181		14,689
Gross unpaid losses and loss expenses, end of year	$	67,811	$	62,690	$	62,960

(1) Net of valuation allowance for uncollectible reinsurance.

(2) Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments and earned premiums totaling $19 million, $53 million, and $85 million for 2020, 2019, and 2018, respectively.

Reconciliation of Claims Development to Liability [Table Text Block]

The following table presents a reconciliation of the loss development tables to the liability for unpaid losses and loss expenses in the consolidated balance sheet:


Reconciliation of Reserve Balances to Liability for Unpaid Loss and Loss Expenses
(in millions of U.S. dollars)	December 31, 2020
Presented in the loss development tables:
North America Commercial P&C Insurance — Workers' Compensation	$	9,600
North America Commercial P&C Insurance — Liability	17,441
North America Commercial P&C Insurance — Other Casualty	2,124
North America Commercial P&C Insurance — Non-Casualty	2,491
North America Personal P&C Insurance	3,025
Overseas General Insurance — Casualty	6,832
Overseas General Insurance — Non-Casualty	2,725
Global Reinsurance — Casualty	1,200
Global Reinsurance — Non-Casualty	312
Excluded from the loss development tables:
Other	4,742
Net unpaid loss and allocated loss adjustment expense	50,492
Ceded unpaid loss and allocated loss adjustment expense:
North America Commercial P&C Insurance — Workers' Compensation	$	1,461
North America Commercial P&C Insurance — Liability	5,743
North America Commercial P&C Insurance — Other Casualty	564
North America Commercial P&C Insurance — Non-Casualty	1,380
North America Personal P&C Insurance	141
Overseas General Insurance — Casualty	2,426
Overseas General Insurance — Non-Casualty	1,686
Global Reinsurance — Casualty	29
Global Reinsurance — Non-Casualty	104
Other	1,153
Ceded unpaid loss and allocated loss adjustment expense	14,687
Unpaid loss and loss expense on other than short-duration contracts (1)	1,109
Unpaid unallocated loss adjustment expenses	1,523
Unpaid losses and loss expenses	$	67,811

(1) Primarily includes the claims reserve of our International A&H business and Life Insurance segment reserves.

Claims Development tables [Table Text Block]

This product line has a substantial geographic spread and a broad mix across industries. Types of coverage include risk management business predominantly with high deductible policies, loss sensitive business (i.e., retrospectively-rated policies), business fronted for captives, as well as excess and primary guaranteed cost coverages.

The triangle below shows all loss and allocated expense development for the workers' compensation product line. In our prior period development disclosure, we exclude any loss development where there is a directly related premium adjustment. For workers' compensation, changes in the exposure base due to payroll audits will drive changes in ultimate losses. In addition, we record involuntary pool assumptions (premiums and losses) on a lagged basis. Both of these items will influence the development in the triangle, particularly the first prior accident year, and are included in the reconciliation table presented on page F-58.


North America Commercial P&C Insurance — Workers' Compensation — Long-tail (continued)
Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,037	$	1,030		$	1,046	$	1,049	$	1,053	$	1,022	$	1,012	$	1,009	$	988	$	973	$	208	45
2012			1,050			1,011		1,030		1,040		1,011		989		986		977		953		234		44
2013						1,109		1,108		1,122		1,127		1,086		1,073		1,037		1,014		280		43
2014								1,207		1,201		1,217		1,215		1,163		1,100		1,073		347		45
2015										1,282		1,259		1,276		1,279		1,217		1,154		419		50
2016												1,367		1,361		1,383		1,378		1,269		530		51
2017														1,413		1,380		1,399		1,393		723		50
2018																1,359		1,361		1,379		709		51
2019																		1,391		1,384		767		47
2020																				1,367		1,086		24
Total																				$	11,959


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	119	$	294		$	411	$	484	$	533	$	567	$	595	$	616	$	640	$	654
2012			111			271		365		436		486		532		574		592		612
2013						107		286		422		506		553		587		616		633
2014								113		295		410		484		532		566		599
2015										116		301		418		501		564		606
2016												122		326		452		529		584
2017														120		313		437		516
2018																130		329		451
2019																		143		341
2020																				111
Total																				$	5,107


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	2,748
Accident years 2011 - 2020 from tables above	6,852
All Accident years	$	9,600

North America Commercial P&C Insurance — Liability — Long-tail

This line consists of primary and excess liability exposures, including medical liability and professional lines, including directors and officers (D&O) liability, errors and omissions (E&O) liability, employment practices liability (EPL), fidelity bonds, and fiduciary liability.

The primary and excess liability business represents the largest part of these exposures. The former includes both monoline and commercial package liability. The latter includes a substantial proportion of commercial umbrella, excess and high excess business, where loss activity can produce significant volatility in the loss triangles at later ages within an accident year (and sometimes across years) due to the size of the limits afforded and the complex nature of the underlying losses.

This line includes management and professional liability products provided to a wide variety of clients, from national accounts to small firms along with private and not-for-profit organizations, distributed through brokers, agents, wholesalers and MGAs. Many of these coverages, particularly D&O and E&O, are typically written on a claims-made form. While most of the coverages are underwritten on a primary basis, there are significant amounts of excess exposure with large policy limits.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	3,500	$	3,586		$	3,630	$	3,665	$	3,593	$	3,498	$	3,384	$	3,316	$	3,193	$	3,143	$	226	25
2012			3,552			3,628		3,613		3,565		3,524		3,426		3,331		3,235		3,235		353		25
2013						3,547		3,542		3,543		3,533		3,430		3,216		3,122		2,964		317		25
2014								3,535		3,586		3,674		3,717		3,656		3,470		3,346		572		25
2015										3,560		3,709		3,819		3,976		3,943		3,736		855		27
2016												3,534		3,595		3,692		3,805		3,799		962		27
2017														3,322		3,499		3,581		3,631		1,475		27
2018																3,375		3,494		3,696		1,737		28
2019																		3,452		3,628		2,381		28
2020																				4,098		3,695		24
Total																				$	35,276



Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	160	$	652		$	1,209	$	1,805	$	2,214	$	2,477	$	2,659	$	2,741	$	2,827	$	2,863
2012			166			656		1,172		1,680		2,092		2,326		2,502		2,619		2,688
2013						130		548		1,192		1,597		2,007		2,232		2,374		2,465
2014								164		679		1,250		1,804		2,202		2,442		2,584
2015										138		605		1,206		1,856		2,291		2,533
2016												171		663		1,336		1,975		2,334
2017														161		617		1,162		1,701
2018																190		754		1,303
2019																		176		671
2020																				152
Total																				$	19,294


North America Commercial P&C Insurance — Liability — Long-tail (continued)
Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	1,459
Accident years 2011 - 2020 from tables above	15,982
All Accident years	$	17,441

This product line consists of the remaining commercial casualty coverages such as automobile liability and aviation. There is also a small portion of commercial multi-peril (CMP) business in accident years 2014 and prior. The paid and reported data are impacted by some catastrophe loss activity primarily on the CMP exposures just noted.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	581	$	590		$	581	$	549	$	533	$	525	$	517	$	511	$	513	$	503	$	13	16
2012			634			606		577		561		520		519		509		507		505		2		16
2013						527		531		523		516		469		462		462		458		21		18
2014								595		583		581		597		555		539		539		25		17
2015										487		470		502		515		458		455		35		15
2016												504		502		527		524		481		61		16
2017														532		566		577		616		118		17
2018																536		564		575		198		17
2019																		606		637		284		16
2020																				646		517		9
Total																				$	5,415


North America Commercial P&C Insurance — Other-Casualty — Long-tail (continued)
Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	86	$	235		$	341	$	400	$	437	$	461	$	466	$	480	$	486	$	486
2012			69			223		320		387		435		470		487		493		502
2013						69		197		271		348		385		411		419		426
2014								80		220		318		391		455		474		501
2015										47		137		215		305		371		395
2016												52		146		246		323		374
2017														66		175		313		381
2018																74		169		270
2019																		70		190
2020																				53
Total																				$	3,578


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	287
Accident years 2011 - 2020 from tables above	1,837
All Accident years	$	2,124

This product line represents first party commercial product lines that are short-tailed in nature, such as property, inland marine, ocean marine, surety and A&H. There is a wide diversity of products, primary and excess coverages, and policy sizes. During this ten-year period, this product line was also impacted by natural catastrophes mainly in the 2012, 2017, and 2018 accident years.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,960	$	1,934		$	1,877	$	1,856	$	1,835	$	1,840	$	1,835	$	1,835	$	1,835	$	1,833	$	4	416
2012			2,033			1,916		1,883		1,864		1,859		1,847		1,844		1,850		1,844		(8)		426
2013						1,434		1,424		1,337		1,360		1,340		1,340		1,338		1,344		7		455
2014								1,643		1,661		1,579		1,559		1,549		1,550		1,558		10		483
2015										1,736		1,745		1,650		1,638		1,605		1,589		(1)		545
2016												1,911		1,890		1,799		1,782		1,818		32		650
2017														2,704		2,608		2,505		2,522		51		763
2018																2,053		2,240		2,175		71		901
2019																		2,052		2,037		166		1,036
2020																				3,150		1,061		927
Total																				$	19,870


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	939	$	1,574		$	1,718	$	1,777	$	1,787	$	1,811	$	1,816	$	1,821	$	1,825	$	1,830
2012			715			1,577		1,698		1,767		1,795		1,822		1,816		1,842		1,844
2013						651		1,138		1,238		1,285		1,311		1,324		1,333		1,335
2014								820		1,374		1,484		1,506		1,532		1,546		1,554
2015										727		1,343		1,488		1,556		1,572		1,574
2016												846		1,504		1,656		1,733		1,761
2017														979		2,087		2,303		2,394
2018																1,027		1,825		2,018
2019																		1,030		1,677
2020																				1,396
Total																				$	17,383


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	4
Accident years 2011 - 2020 from tables above	2,487
All Accident years	$	2,491

North America Personal P&C Insurance — Short-tail

Chubb provides personal lines coverages for high-net-worth individuals and families in North America including homeowners, automobile, valuable articles (including fine art), umbrella liability, and recreational marine insurance offered through independent regional agents and brokers. A portfolio acquired from Fireman’s Fund is presented on a prospective basis beginning in May of accident year 2015. Reserves associated with prior accident periods were acquired through a loss portfolio transfer, which does not allow for a retrospective presentation. During this ten-year period, this segment was also impacted by natural catastrophes, mainly in 2012, 2017 and 2018 accident years.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	2,208	$	2,210		$	2,185	$	2,173	$	2,164	$	2,161	$	2,160	$	2,158	$	2,159	$	2,157	$	7	179
2012			2,185			2,183		2,183		2,191		2,186		2,186		2,189		2,194		2,190		18		188
2013						1,860		1,888		1,897		1,900		1,924		1,937		1,945		1,948		26		132
2014								2,205		2,206		2,192		2,146		2,160		2,147		2,141		14		144
2015										2,494		2,550		2,561		2,544		2,563		2,570		21		148
2016												2,440		2,535		2,545		2,482		2,471		45		154
2017														3,035		3,069		3,002		2,998		96		163
2018																3,010		3,037		3,103		244		169
2019																		2,957		2,993		329		155
2020																				2,931		1,119		100
Total																				$	25,502


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,360	$	1,835		$	1,972	$	2,052	$	2,105	$	2,129	$	2,139	$	2,146	$	2,148	$	2,149
2012			1,177			1,806		1,957		2,063		2,117		2,149		2,164		2,163		2,165
2013						1,043		1,504		1,688		1,787		1,843		1,885		1,895		1,917
2014								1,310		1,765		1,926		2,035		2,080		2,106		2,116
2015										1,499		2,084		2,271		2,392		2,478		2,508
2016												1,453		2,052		2,211		2,314		2,370
2017														1,698		2,520		2,668		2,799
2018																1,926		2,549		2,706
2019																		1,668		2,437
2020																				1,334
Total																				$	22,501


North America Personal P&C Insurance — Short-tail (continued)
Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	24
Accident years 2011 - 2020 from tables above	3,001
All Accident years	$	3,025

This product line is comprised of D&O liability, E&O liability, financial institutions (including crime/fidelity coverages), and non-U.S. general liability as well as aviation and political risk. Exposures are located around the world, including Europe, Latin America, and Asia. Approximately 45 percent of Chubb Overseas General business is generated by European accounts, exclusive of Lloyd's market. There is some U.S. exposure in Casualty from multinational accounts and in financial lines for Lloyd's market. The financial lines coverages are typically written on a claims-made form, while general liability coverages are typically on an occurrence basis and comprised of a mix of primary and excess businesses.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,255	$	1,262		$	1,254	$	1,244	$	1,158	$	1,090	$	1,079	$	1,027	$	1,023	$	1,025	$	31	37
2012			1,290			1,261		1,326		1,346		1,343		1,337		1,315		1,304		1,272		87		38
2013						1,281		1,279		1,276		1,322		1,276		1,242		1,182		1,148		86		39
2014								1,279		1,352		1,362		1,378		1,293		1,206		1,165		151		39
2015										1,196		1,296		1,328		1,351		1,326		1,265		199		41
2016												1,232		1,337		1,407		1,437		1,425		341		43
2017														1,227		1,332		1,381		1,433		384		43
2018																1,330		1,383		1,447		671		43
2019																		1,409		1,480		809		40
2020																				1,810		1,493		28
Total																				$	13,470


Overseas General Insurance — Casualty — Long-tail (continued)
Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	86	$	243		$	393	$	528	$	631	$	713	$	789	$	842	$	876	$	901
2012			75			252		441		597		713		857		929		973		1,040
2013						85		267		428		579		725		829		899		952
2014								111		293		473		608		725		811		876
2015										86		287		497		679		802		884
2016												127		324		534		687		815
2017														98		323		535		702
2018																112		334		503
2019																		126		341
2020																				110
Total																				$	7,124


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	486
Accident years 2011 - 2020 from tables above	6,346
All Accident years	$	6,832

This product line is comprised of commercial fire, marine (predominantly cargo), surety, personal automobile (in Latin America, Asia Pacific and Japan), personal cell phones, personal residential (including high net worth), energy and construction. In general, these lines have relatively stable payment and reporting patterns although they are impacted by natural catastrophes mainly in the 2011, 2017, and 2018 accident years. Latin America and Europe each make up about 30 percent of the Chubb Overseas General non-casualty book.


Overseas General Insurance — Non-Casualty — Short-tail (continued)
Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves		Reported Claims (in thousands)
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	1,908	$	1,995		$	1,938	$	1,898	$	1,879	$	1,867	$	1,859	$	1,849	$	1,844	$	1,843	$	6	543
2012			1,712			1,702		1,661		1,605		1,599		1,590		1,575		1,570		1,562		13		555
2013						1,787		1,780		1,714		1,665		1,660		1,633		1,620		1,610		19		573
2014								1,863		1,932		1,875		1,864		1,828		1,817		1,810		7		548
2015										1,963		2,083		2,062		2,030		2,011		2,003		24		571
2016												2,070		2,071		2,058		2,036		2,040		22		581
2017														2,222		2,264		2,245		2,225		18		589
2018																2,186		2,276		2,237		48		624
2019																		2,208		2,228		94		640
2020																				2,571		804		518
Total																				$	20,129


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	765	$	1,486		$	1,694	$	1,750	$	1,780	$	1,795	$	1,804	$	1,808	$	1,807	$	1,806
2012			679			1,237		1,425		1,485		1,508		1,518		1,530		1,532		1,532
2013						696		1,284		1,480		1,512		1,549		1,567		1,575		1,578
2014								758		1,438		1,651		1,715		1,746		1,759		1,774
2015										857		1,560		1,793		1,875		1,897		1,927
2016												1,013		1,679		1,881		1,954		1,981
2017														1,051		1,848		2,029		2,106
2018																1,006		1,753		1,962
2019																		1,050		1,747
2020																				1,085
Total																				$	17,498


(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	94
Accident years 2011 - 2020 from tables above	2,631
All Accident years	$	2,725

This product line includes proportional and excess coverages in general, automobile liability, professional liability, medical malpractice and workers' compensation, with exposures located around the world. In general, reinsurance exhibits less stable development patterns than primary business. In particular, general casualty reinsurance and excess coverages are long-tailed and can be very volatile.


Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	408	$	415		$	430	$	433	$	428	$	418	$	415	$	409	$	402	$	389	$	15
2012			387			384		392		395		379		373		372		374		379		11
2013						321		327		330		331		332		324		317		311		13
2014								334		335		340		343		345		348		331		16
2015										285		290		300		301		309		306		22
2016												224		228		236		236		245		27
2017														215		217		221		218		28
2018																246		249		256		48
2019																		239		248		90
2020																				247		153
Total																				$	2,930


Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	70	$	146		$	195	$	236	$	267	$	292	$	312	$	325	$	332	$	338
2012			78			168		223		262		293		309		324		336		342
2013						65		143		186		222		242		260		269		272
2014								92		185		218		249		265		277		287
2015										90		159		192		217		233		250
2016												58		113		143		159		175
2017														47		100		122		140
2018																42		96		126
2019																		40		90
2020																				41
Total																				$	2,061


Global Reinsurance — Casualty — Long-tail (continued)
Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	331
Accident years 2011 - 2020 from tables above	869
All Accident years	$	1,200

This product line includes property, property catastrophe, marine, credit/surety, A&H and energy. This product line is impacted by natural catastrophes, particularly in the 2011, 2017 and 2018 accident years. Of the non-catastrophe book, the mixture of business varies by year with approximately 77 percent of loss on proportional treaties in treaty year 2011 and after. This percentage has increased over time with the proportion being approximately 59 percent for treaty years 2011 to 2012 growing to an average of 82 percent for treaty years 2013 to 2020, with the remainder being written on an excess of loss basis.


Global Reinsurance — Non-Casualty — Short-tail (continued)
Net Incurred Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31						As of December 31 2020
(in millions of U.S. dollars)					Unaudited																	Net IBNR Reserves
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	277	$	279		$	276	$	266	$	267	$	268	$	267	$	268	$	267	$	269	$	1
2012			233			211		202		192		191		188		186		186		184		1
2013						162		160		148		143		144		141		141		140		—
2014								167		182		183		186		184		183		182		3
2015										147		155		162		162		155		161		4
2016												184		189		192		194		190		5
2017														397		424		454		451		10
2018																288		300		303		(8)
2019																		143		141		29
2020																				212		110
Total																				$	2,233


Global Reinsurance — Non-Casualty — Short-tail (continued)
Net Cumulative Paid Loss and Allocated Loss Adjustment Expenses
																Years Ended December 31
(in millions of U.S. dollars)					Unaudited
Accident Year	2011		2012			2013		2014		2015		2016		2017		2018		2019		2020
2011	$	87	$	179		$	210	$	236	$	254	$	259	$	262	$	263	$	264	$	265
2012			45			130		157		167		173		178		180		181		180
2013						46		103		121		131		134		137		137		139
2014								66		131		154		165		171		173		175
2015										56		104		133		143		147		153
2016												57		133		161		172		178
2017														191		322		402		415
2018																94		258		277
2019																		35		86
2020																				63
Total																				$	1,931


Net Liabilities for Loss and Allocated Loss Adjustment Expenses
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	10
Accident years 2011 - 2020 from tables above	302
All Accident years	$	312

Supplementary PPD [Table Text Block]


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(94)
Accident years 2011 - 2020 from tables above	(256)
All Accident years	$	(350)


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(176)
Accident years 2011 - 2020 from tables above	(117)
All Accident years	$	(293)


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	23
Accident years 2011 - 2020 from tables above	19
All Accident years	$	42


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	2
Accident years 2011 - 2020 from tables above	(37)
All Accident years	$	(35)


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(1)
Accident years 2011 - 2020 from tables above	85
All Accident years	$	84


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(59)
Accident years 2011 - 2020 from tables above	9
All Accident years	$	(50)


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(8)
Accident years 2011 - 2020 from tables above	(69)
All Accident years	$	(77)


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	(10)
Accident years 2011 - 2020 from tables above	(12)
All Accident years	$	(22)


Supplementary Information: (Favorable)/ Adverse Prior Period Development
(in millions of U.S. dollars)	December 31, 2020
Accident years prior to 2011	$	—
Accident years 2011 - 2020 from tables above	(2)
All Accident years	$	(2)

Schedule of Historical Claims [Table Text Block]



Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	10	%	16	%	10	%	7	%	5	%	4	%	3	%	2	%	2	%	1	%


Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	5	%	14	%	17	%	16	%	12	%	7	%	5	%	3	%	2	%	1	%



Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	12	%	23	%	19	%	14	%	10	%	5	%	3	%	2	%	1	%	—	%


North America Commercial P&C Insurance — Non-Casualty — Short-tail (continued)
Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	46	%	38	%	8	%	3	%	1	%	1	%	—	%	1	%	—	%	—	%


Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	57	%	24	%	7	%	5	%	3	%	1	%	1	%	—	%	—	%	—	%



Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	8	%	15	%	15	%	12	%	10	%	8	%	6	%	4	%	4	%	3	%


Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	45	%	35	%	11	%	3	%	2	%	1	%	1	%	—	%	—	%	—	%


Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	21	%	23	%	12	%	10	%	7	%	5	%	4	%	3	%	2	%	2	%



Supplementary Information: Average Annual Percentage Payout of Net Incurred Claims by Age, as of December 31, 2020 (Unaudited)
Age in Years	1		2		3		4		5		6		7		8		9		10
Percentage	33	%	38	%	14	%	6	%	4	%	2	%	1	%	1	%	—	%	—	%

Supplementary PPD Reconciliation [Table Text Block]

The following table presents a reconciliation of the loss development triangles above to prior period development:


	Components of PPD
Year Ended December 31, 2020 (in millions of U.S. dollars) (favorable)/unfavorable	2011 - 2019 accident years (implied PPD per loss triangles)		Accident years prior to 2011		Other (1)			PPD on loss reserves		RIPs, Expense adjustments, and earned premiums			Total
North America Commercial P&C Insurance
Long-tail	$	(354)	$	(247)	$	(102)		$	(703)	$	31		$	(672)
Short-tail	(37)		2		5			(30)		—			(30)
	(391)		(245)		(97)		(2)	(733)		31		(3)	(702)
North America Personal P&C Insurance (Short-tail)	85		(1)		(3)			81		(18)			63
Overseas General Insurance
Long-tail	9		(59)		1			(49)		—			(49)
Short-tail	(69)		(8)		(24)			(101)		—			(101)
	(60)		(67)		(23)		(4)	(150)		—			(150)
Global Reinsurance
Long-tail	(12)		(10)		(1)			(23)		(2)			(25)
Short-tail	(2)		—		(1)			(3)		(1)			(4)
	(14)		(10)		(2)			(26)		(3)			(29)
Subtotal	$	(380)	$	(323)	$	(125)		$	(828)	$	10		$	(818)
North America Agricultural Insurance (Short-tail)								$	(19)	$	9		$	(10)
Corporate (Long-tail)								433		—			433
Consolidated PPD								$	(414)	$	19		$	(395)

(1) Other includes the impact of foreign exchange.

(2) Includes favorable development of $80 million related to our Alternative Risk Solutions business (U.S. and Bermuda) and an adjustment to exclude $15 million in unfavorable development in the workers' compensation line, associated with an increase in exposure for which additional premiums were collected; the remaining difference relates to a number of other items, none of which are individually material.

(3) Includes premium returns associated with our Alternative Risk Solutions business, which is excluded from the triangles.

(4) Includes favorable development of $22 million related to International A&H business; the remaining difference relates to a number of other items, none of which are individually material.

Prior Period Development, by Segment [Table Text Block]


Years Ended December 31 (in millions of U.S. dollars, except for percentages)	Long-tail		Short-tail		Total		% of beginning net unpaid reserves (1)
2020
North America Commercial P&C Insurance	$	(672)	$	(30)	$	(702)	1.4	%
North America Personal P&C Insurance	—		63		63		0.1	%
North America Agricultural Insurance	—		(10)		(10)		—	%
Overseas General Insurance	(49)		(101)		(150)		0.3	%
Global Reinsurance	(25)		(4)		(29)		0.1	%
Corporate	433		—		433		0.9	%
Total	$	(313)	$	(82)	$	(395)	0.8	%
2019
North America Commercial P&C Insurance	$	(668)	$	19	$	(649)	1.3	%
North America Personal P&C Insurance	—		(95)		(95)		0.2	%
North America Agricultural Insurance	—		(80)		(80)		0.2	%
Overseas General Insurance	(68)		(24)		(92)		0.2	%
Global Reinsurance	(59)		30		(29)		0.1	%
Corporate	153		—		153		0.3	%
Total	$	(642)	$	(150)	$	(792)	1.6	%
2018
North America Commercial P&C Insurance	$	(395)	$	(215)	$	(610)	1.2	%
North America Personal P&C Insurance	—		41		41		0.1	%
North America Agricultural Insurance	—		(110)		(110)		0.2	%
Overseas General Insurance	(67)		(145)		(212)		0.4	%
Global Reinsurance	(69)		19		(50)		0.1	%
Corporate	45		—		45		0.1	%
Total	$	(486)	$	(410)	$	(896)	1.8	%

(1) Calculated based on the beginning of period consolidated net unpaid losses and loss expenses.

Schedule Of Asbestos Environmental Loss Roll Forward and by segment

The following table presents a roll-forward of consolidated A&E loss reserves including allocated loss expense reserves for A&E exposures, and the valuation allowance for uncollectible paid and unpaid reinsurance recoverables:


	Asbestos				Environmental				Total
(in millions of U.S. dollars)	Gross		Net		Gross		Net		Gross		Net
Balance at December 31, 2017	$	1,621	$	1,051	$	607	$	476	$	2,228	$	1,527
Incurred activity	136		75		101		(97)		237		(22)		(1)
Paid activity	(265)		(162)		(83)		104		(348)		(58)
Balance at December 31, 2018	1,492		964		625		483		2,117		1,447
Incurred activity	129		70		46		28		175		98		(1)
Paid activity	(162)		(118)		(142)		(101)		(304)		(219)
Balance at December 31, 2019	1,459		916		529		410		1,988		1,326
Incurred activity	150		90		79		41		229		131		(1)
Paid activity	(258)		(133)		(91)		(72)		(349)		(205)
Balance at December 31, 2020	$	1,351	$	873	$	517	$	379	$	1,868	$	1,252

(1) Excludes unallocated loss expenses and the net activity reflects third-party reinsurance other than the aggregate excess of loss reinsurance provided by National Indemnity Company (NICO) to Westchester Specialty (see Westchester Specialty section below).

The A&E net loss reserves including allocated loss expense reserves and valuation allowance for uncollectible reinsurance at December 31, 2020 and 2019 shown in the table above is comprised of:


	December 31
(in millions of U.S. dollars)	2020		2019
Brandywine operations	$	736	$	754
Westchester Specialty	103		117
Chubb Corp	333		381
Other, mainly Overseas General Insurance	80		74
Total	$	1,252	$	1,326

Taxation (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of components of income tax provision

The following table presents pre-tax income and the related provision for income taxes:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Pre-tax income:
Switzerland	$	350	$	440	$	950
Outside Switzerland	3,812		4,809		3,707
Total pre-tax income	$	4,162	$	5,249	$	4,657
Provision for income taxes
Current tax expense:
Switzerland	$	52	$	29	$	89
Outside Switzerland	876		879		563
Total current tax expense	928		908		652
Deferred tax expense (benefit):
Switzerland	2		11		3
Outside Switzerland	(301)		(124)		40
Total deferred tax expense (benefit)	(299)		(113)		43
Provision for income taxes	$	629	$	795	$	695

Reconciliation schedule of the difference between the provision for income taxes and the expected tax provision at the Swiss statutory income tax rate

The following table presents a reconciliation of the difference between the provision for income taxes and the expected tax provision at the Swiss statutory income tax rate:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Expected tax provision at Swiss statutory tax rate	$	880	$	411	$	365
Permanent differences:
Taxes on earnings subject to rate other than Swiss statutory rate	(337)		376		372
Tax-exempt interest and dividends received deduction, net of proration	(41)		(49)		(75)
Net withholding taxes	67		40		33
Share-based compensation	(10)		(12)		(19)
Impact of 2017 Tax Act	—		—		(25)
Other	70		29		44
Provision for income taxes	$	629	$	795	$	695

Schedule of the components of net deferred tax assets

The following table presents the components of net deferred tax assets and liabilities:


	December 31		December 31
(in millions of U.S. dollars)	2020		2019
Deferred tax assets:
Loss reserve discount	$	884	$	826
Unearned premiums reserve	496		519
Foreign tax credits	222		247
Provision for uncollectible balances	46		37
Loss carry-forwards	123		143
Debt related amounts	69		74
Compensation related amounts	281		261
Cumulative translation adjustments	120		33
Investments	75		—
Lease liability	121		140

Total deferred tax assets	2,437		2,280
Deferred tax liabilities:
Deferred policy acquisition costs	522		588
Other intangible assets, including VOBA	1,425		1,468
Un-remitted foreign earnings	77		73
Investments	—		40
Unrealized appreciation on investments	957		470
Depreciation	123		157
Lease right-of-use asset	111		129
Other, net	31		45
Total deferred tax liabilities	3,246		2,970
Valuation allowance	83		114
Net deferred tax liabilities	$	(892)	$	(804)

Reconciliation schedule of unrecognized tax benefits

The following table presents a reconciliation of the beginning and ending amount of gross unrecognized tax benefits:


	December 31		December 31
(in millions of U.S. dollars)	2020		2019
Balance, beginning of year	$	47	$	14
Additions based on tax positions related to the current year	5		12
Additions based on tax positions related to prior years	24		23


Reductions for the lapse of the applicable statutes of limitations	—		(2)
Balance, end of year	$	76	$	47

Summary of Income Tax Examinations [Table Text Block]

The following table summarizes tax years open for examination by major income tax jurisdiction:


At December 31, 2020
Australia	2014	-	2020
Canada	2012	-	2020
France	2018	-	2020
Germany	2015	-	2020
Italy	2010	-	2020
Mexico	2014	-	2020
Spain	2012	-	2020
Switzerland	2016	-	2020
United Kingdom	2015	-	2020
United States	2014	-	2020

Debt (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of debt outstanding


	December 31		December 31
(in millions of U.S. dollars)	2020		2019		Early Redemption Option
Repurchase agreements (weighted average interest rate of 0.3% in 2020 and 2.2% in 2019)	$	1,405	$	1,416	None
Short-term debt
Chubb INA:
$1,300 million 2.3% due November 2020	$	—	$	1,298	Make-whole premium plus 15 bps
Other short-term debt 2.75% due September 2020	—		1		None
Total short-term debt	$	—	$	1,299
Long-term debt
Chubb INA:
$1,000 million 2.875% senior notes due November 2022	$	998	$	997	Make-whole premium plus 20 bps
$475 million 2.7% senior notes due March 2023	474		473		Make-whole premium plus 10 bps
$700 million 3.35% senior notes due May 2024	698		697		Make-whole premium plus 15 bps
€700 million 0.3% senior notes due December 2024	841		776		Make-whole premium plus 15 bps
$800 million 3.15% senior notes due March 2025	797		796		Make-whole premium plus 15 bps
$1,500 million 3.35% senior notes due May 2026	1,493		1,492		Make-whole premium plus 20 bps
€575 million 0.875% senior notes due June 2027	691		635		Make-whole premium plus 20 bps
€900 million 1.55% senior notes due March 2028	1,079		993		Make-whole premium plus 15 bps
$100 million 8.875% debentures due August 2029	100		100		None
€700 million 0.875% senior notes due December 2029	840		775		Make-whole premium plus 20 bps
$1,000 million 1.375% senior notes due September 2030	991		—		Make-whole premium plus 15 bps
€575 million 1.4% senior notes due June 2031	687		633		Make-whole premium plus 25 bps
$200 million 6.8% debentures due November 2031	242		246		Make-whole premium plus 25 bps
$300 million 6.7% senior notes due May 2036	298		297		Make-whole premium plus 20 bps
$800 million 6.0% senior notes due May 2037	945		953		Make-whole premium plus 20 bps
€900 million 2.5% senior notes due March 2038	1,077		992		Make-whole premium plus 25 bps
$600 million 6.5% senior notes due May 2038	743		751		Make-whole premium plus 30 bps
$475 million 4.15% senior notes due March 2043	470		470		Make-whole premium plus 15 bps
$1,500 million 4.35% senior notes due November 2045	1,484		1,483		Make-whole premium plus 25 bps
Total long-term debt	$	14,948	$	13,559
Trust preferred securities
Chubb INA capital securities due April 2030	$	308	$	308	Redemption prices(1)

Commitments, contingencies, and guarantees (Tables)

12 Months Ended

Dec. 31, 2020

Commitments and Contingencies Disclosure [Abstract]

Balance Sheet Locations, Fair Values In An Asset Or (Liability) Position, And Notional Values/Payment Provisions Of Derivative Instruments

The following table presents the balance sheet locations, fair values of derivative instruments in an asset or (liability) position, and notional values/payment provisions of our derivative instruments:


		December 31, 2020							December 31, 2019
	Consolidated Balance Sheet Location	Fair Value				Notional Value/ Payment Provision			Fair Value					Notional Value/ Payment Provision
		Derivative Asset		Derivative (Liability)				Derivative Asset			Derivative (Liability)
(in millions of U.S. dollars)
Investment and embedded derivative instruments:
Foreign currency forward contracts	OA / (AP)	$	22	$	(49)	$	2,807		$	11		$	(78)	$	2,579



Options/Futures contracts on notes, bonds, and equities	OA / (AP)	13		(3)		1,749			13			(15)		1,615

Convertible securities (1)	FM AFS / ES	9		—		11			4			—		5

		$	44	$	(52)	$	4,567		$	28		$	(93)	$	4,199
Other derivative instruments:
Futures contracts on equities (2)	OA / (AP)	$	—	$	(17)	$	709		$	—		$	(13)	$	613


Other	OA / (AP)	—		—		16			2			—		63
		$	—	$	(17)	$	725		$	2		$	(13)	$	676
GLB (3)	(AP)	$	—	$	(1,089)	$	1,658		$	—		$	(897)	$	1,510

(1)Includes fair value of embedded derivatives.

(2)Related to GMDB and GLB book of business.

(3)Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.

Secured Borrowings Securities Lending Table

The following table presents the carrying value of collateral held under securities lending agreements by investment category and remaining contractual maturity of the underlying agreements:


	Remaining contractual maturity
	December 31, 2020		December 31, 2019
(in millions of U.S. dollars)	Overnight and Continuous
Collateral held under securities lending agreements:
Cash	$	551	$	346
U.S. Treasury / Agency	148		6
Non-U.S.	1,032		595
Corporate and asset-backed securities	30		5
Mortgage-backed securities	4		18

Equity securities	79		24

	$	1,844	$	994
Gross amount of recognized liability for securities lending payable	$	1,844	$	994

At December 31, 2020 and 2019, our repurchase agreement obligations of $1,405 million and $1,416 million, respectively, were fully collateralized. In contrast to securities lending programs, the use of cash received is not restricted for the repurchase obligations. The fair value of the underlying securities sold remains in Fixed maturities available for sale, and the repurchase agreement obligation is recorded in Repurchase agreements in the Consolidated balance sheets.

The following table presents the carrying value of collateral pledged under repurchase agreements by investment category and remaining contractual maturity of the underlying agreements:


	Remaining contractual maturity
	December 31, 2020									December 31, 2019
	30-90 Days		Greater than 90 Days					Up to 30 Days		30-90 Days		Greater than 90 Days		Total
(in millions of U.S. dollars)					Total
Collateral pledged under repurchase agreements:
Cash	$	—	$	4		$	4	$	2	$	—	$	—	$	2
U.S. Treasury / Agency	—		106			106		107		—		—		107


Mortgage-backed securities	481		871			1,352		399		476		480		1,355


	$	481	$	981		$	1,462	$	508	$	476	$	480	$	1,464
Gross amount of recognized liabilities for repurchase agreements						$	1,405							$	1,416
Difference (1)						$	57							$	48

(1)Per the repurchase agreements, the amount of collateral posted is required to exceed the amount of gross liability.

Derivative Instruments, Gain (Loss) [Table Text Block]

The following table presents net realized gains (losses) related to derivative instrument activity in the Consolidated statements of operations:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Investment and embedded derivative instruments:
Foreign currency forward contracts	$	65	$	(79)	$	3
Interest rate swaps	—		(270)		(115)
All other futures contracts, options, and equities	16		(88)		39
Convertible securities (1)	—		2		(2)
Total investment and embedded derivative instruments	$	81	$	(435)	$	(75)
GLB and other derivative instruments:
GLB	$	(202)	$	(4)	$	(248)
Futures contracts on equities (2)	(108)		(138)		(4)

Other	1		(8)		(3)
Total GLB and other derivative instruments	$	(309)	$	(150)	$	(255)
	$	(228)	$	(585)	$	(330)

(1)Includes embedded derivatives.

(2)Related to GMDB and GLB book of business.

Schedule of Future Minimum Rental Payments for Operating Leases

Future minimum lease payments under the operating leases are expected to be as follows:


For the years ending December 31
(in millions of U.S. dollars)
Undiscounted cash flows:
2021	$	150
2022	123
2023	96
2024	68
2025	38
Thereafter	75
Total undiscounted lease payments	$	550
Less: Present value adjustment	33
Net lease liabilities reported as of December 31, 2020	$	517

Shareholders' equity note (Tables)

12 Months Ended

Dec. 31, 2020

Stockholders' Equity Note [Abstract]

Dividends Declared [Table Text Block]

The following table presents dividend distributions per Common Share in Swiss francs (CHF) and U.S. dollars (USD):


	Year Ended December 31
		2020			2019			2018
	CHF	USD		CHF	USD		CHF	USD
Total dividend distributions per common share	2.89	$	3.09	2.94	$	2.98	2.84	$	2.90

Schedule of changes in Common Shares issued and outstanding


	Year Ended December 31
	2020	2019	2018
Common Shares authorized and issued, beginning of year	479,783,864	479,783,864	479,783,864
Cancellation of treasury shares	(2,178,600)	—	—
Common Shares authorized and issued, end of year	477,605,264	479,783,864	479,783,864
Common Shares in treasury, beginning of year (at cost)	(27,812,297)	(20,580,486)	(15,950,685)
Net shares issued under employee share-based compensation plans	2,345,208	3,210,427	3,089,234
Shares repurchased	(3,584,150)	(10,442,238)	(7,719,035)
Cancellation of treasury shares	2,178,600	—	—
Common Shares in treasury, end of year (at cost)	(26,872,639)	(27,812,297)	(20,580,486)
Common Shares outstanding, end of year	450,732,625	451,971,567	459,203,378

Share Repurchase Program [Table Text Block]

The following table presents repurchases of Chubb's Common Shares conducted in a series of open market transactions under the Board authorizations:


	Year Ended December 31						January 1, 2021 through
(in millions of U.S. dollars, except share data)	2020		2019		2018		February 24, 2021
Number of shares repurchased	3,584,150		10,442,238		7,719,035		1,971,000
Cost of shares repurchased (1)	$	516	$	1,531	$	1,021	$	327

Share-based compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of pre-tax and after-tax share-based compensation expense

The following table presents pre-tax and after-tax share-based compensation expense:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Stock options and shares issued under ESPP:
Pre-tax	$	45	$	42	$	50
After-tax (1)	$	38	$	39	$	40
Restricted stock:
Pre-tax	$	210	$	224	$	235
After-tax (1)	$	164	$	180	$	178

(1)The windfall tax benefit recorded to Income tax expense in the Consolidated statement of operations was $10 million, $12 million, and $19 million for the years ended December 31, 2020, 2019, and 2018, respectively.

Schedule of the weighted-average model valuation assumptions


	Year Ended December 31
	2020		2019		2018
Dividend yield	2.1	%	2.2	%	2.0	%
Expected volatility	18.0	%	16.0	%	23.2	%
Risk-free interest rate	1.2	%	2.6	%	2.7	%
Expected life	5.7 years		5.7 years		5.7 years

Rollforward of the company's stock options

The following table presents a roll-forward of Chubb's stock options:


(Intrinsic Value in millions of U.S. dollars)	Number of Options	Weighted-Average Exercise Price		Weighted-Average Fair Value		Total Intrinsic Value
Options outstanding, December 31, 2017	10,433,316	$	99.20
Granted	1,842,690	$	143.07	$	29.71
Exercised	(1,065,384)	$	73.57			$	71
Forfeited and expired	(202,900)	$	133.92
Options outstanding, December 31, 2018	11,007,722	$	108.25
Granted	2,073,940	$	133.90	$	18.76
Exercised	(1,944,604)	$	84.13			$	122
Forfeited and expired	(251,801)	$	136.87
Options outstanding, December 31, 2019	10,885,257	$	116.79
Granted	1,958,279	$	150.10	$	19.89
Exercised	(1,158,633)	$	86.90			$	76
Forfeited and expired	(206,720)	$	138.77
Options outstanding, December 31, 2020	11,478,183	$	125.09			$	331
Options exercisable, December 31, 2020	7,792,343	$	116.35			$	293

Rollforward of the company's restricted stock

The following table presents a roll-forward of our restricted stock awards. Included in the roll-forward below are 27,679 restricted stock awards, 19,019 restricted stock awards, and 20,784 restricted stock awards that were granted to non-management directors during the years ended December 31, 2020, 2019, and 2018, respectively:


	Service-based Restricted Stock Awards and Restricted Stock Units			Performance-based Restricted Stock Awards and Restricted Stock Units
	Number of Shares	Weighted-Average Grant-Date Fair Value		Number of Shares	Weighted-Average Grant-Date Fair Value
Unvested restricted stock, December 31, 2017	4,709,442	$	121.16	975,497	$	118.28
Granted	1,326,979	$	142.76	180,065	$	143.07
Vested	(2,545,090)	$	114.83	(244,332)	$	103.03
Forfeited	(196,482)	$	131.06	—	$	—
Unvested restricted stock, December 31, 2018	3,294,849	$	134.17	911,230	$	127.27
Granted	1,492,900	$	134.38	212,059	$	133.90
Vested	(1,292,864)	$	129.18	(196,640)	$	115.62
Forfeited	(200,875)	$	135.98	(50,437)	$	132.36
Unvested restricted stock, December 31, 2019	3,294,010	$	136.20	876,212	$	131.16
Granted	1,425,667	$	148.56	186,291	$	151.14
Vested	(1,304,308)	$	134.02	(490,185)	$	125.66
Forfeited	(152,074)	$	140.72	—	$	—
Unvested restricted stock, December 31, 2020	3,263,295	$	142.32	572,318	$	142.38

Postretirement benefits (Tables)

12 Months Ended

Dec. 31, 2020

Retirement Benefits [Abstract]

Schedule of Net Funded Status [Table Text Block]

Obligations and funded status

The funded status of the pension and other postretirement benefit plans as well as the amounts recognized in Accumulated other comprehensive income at December 31, 2020 and 2019 was as follows:


	Pension Benefit Plans								Other Postretirement Benefit Plans
	2020				2019				2020		2019
	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
Benefit obligation, beginning of year	$	3,569	$	1,042	$	3,092	$	942	$	103	$	113

Service cost	—		4		49		11		1		—
Interest cost	99		22		118		27		2		4
Actuarial loss (gain)	441		135		443		124		1		3
Benefits paid	(127)		(31)		(121)		(39)		(20)		(17)

Curtailments	—		(2)		—		(4)		—		—
Settlements	(15)		—		(12)		(61)		—		—
Foreign currency revaluation and other	—		29		—		42		(1)		—
Benefit obligation, end of year	$	3,967	$	1,199	$	3,569	$	1,042	$	86	$	103
Plan assets at fair value, beginning of year	$	3,301	$	1,141	$	2,784	$	1,008	$	152	$	143

Actual return on plan assets	563		126		636		169		6		9
Employer contributions	17		19		14		16		1		—
Benefits paid	(127)		(31)		(121)		(39)		(39)		—
Settlements	(15)		—		(12)		(61)		—		—
Foreign currency revaluation and other	—		29		—		48		—		—
Plan assets at fair value, end of year	$	3,739	$	1,284	$	3,301	$	1,141	$	120	$	152
Funded status at end of year	$	(228)	$	85	$	(268)	$	99	$	34	$	49
Amounts recognized in Accumulated other comprehensive income, not yet recognized in net periodic cost (benefit):
Net actuarial loss (gain)	$	78	$	163	$	(21)	$	110	$	(5)	$	(3)
Prior service cost (benefit)	—		9		—		10		(31)		(114)
Total	$	78	$	172	$	(21)	$	120	$	(36)	$	(117)

Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]

The funded status of the pension and other postretirement benefit plans as well as the amounts recognized in Accumulated other comprehensive income at December 31, 2020 and 2019 was as follows:


	Pension Benefit Plans								Other Postretirement Benefit Plans
	2020				2019				2020		2019
	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
Benefit obligation, beginning of year	$	3,569	$	1,042	$	3,092	$	942	$	103	$	113

Service cost	—		4		49		11		1		—
Interest cost	99		22		118		27		2		4
Actuarial loss (gain)	441		135		443		124		1		3
Benefits paid	(127)		(31)		(121)		(39)		(20)		(17)

Curtailments	—		(2)		—		(4)		—		—
Settlements	(15)		—		(12)		(61)		—		—
Foreign currency revaluation and other	—		29		—		42		(1)		—
Benefit obligation, end of year	$	3,967	$	1,199	$	3,569	$	1,042	$	86	$	103
Plan assets at fair value, beginning of year	$	3,301	$	1,141	$	2,784	$	1,008	$	152	$	143

Actual return on plan assets	563		126		636		169		6		9
Employer contributions	17		19		14		16		1		—
Benefits paid	(127)		(31)		(121)		(39)		(39)		—
Settlements	(15)		—		(12)		(61)		—		—
Foreign currency revaluation and other	—		29		—		48		—		—
Plan assets at fair value, end of year	$	3,739	$	1,284	$	3,301	$	1,141	$	120	$	152
Funded status at end of year	$	(228)	$	85	$	(268)	$	99	$	34	$	49
Amounts recognized in Accumulated other comprehensive income, not yet recognized in net periodic cost (benefit):
Net actuarial loss (gain)	$	78	$	163	$	(21)	$	110	$	(5)	$	(3)
Prior service cost (benefit)	—		9		—		10		(31)		(114)
Total	$	78	$	172	$	(21)	$	120	$	(36)	$	(117)

Defined Benefit Plan, Plan with Projected Benefit Obligation in Excess of Plan Assets [Table Text Block]

The following table provides information on pension plans where the benefit obligation is in excess of plan assets at December 31, 2020 and 2019:


	2020				2019
	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
Plans with projected benefit obligation in excess of plan assets:
Projected benefit obligation	$	3,967	$	629	$	3,569	$	236
Fair value of plan assets	3,739		568		3,301		175
Net funded status	$	(228)	$	(61)	$	(268)	$	(61)
Plans with accumulated benefit obligation in excess of plan assets:
Accumulated benefit obligation	$	3,967	$	593	$	3,569	$	173
Fair value of plan assets	$	3,739	$	565	$	3,301	$	140

Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Table Text Block]

The following table provides information on pension plans where the benefit obligation is in excess of plan assets at December 31, 2020 and 2019:


	2020				2019
	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
Plans with projected benefit obligation in excess of plan assets:
Projected benefit obligation	$	3,967	$	629	$	3,569	$	236
Fair value of plan assets	3,739		568		3,301		175
Net funded status	$	(228)	$	(61)	$	(268)	$	(61)
Plans with accumulated benefit obligation in excess of plan assets:
Accumulated benefit obligation	$	3,967	$	593	$	3,569	$	173
Fair value of plan assets	$	3,739	$	565	$	3,301	$	140

Defined Benefit Plan, Assumptions [Table Text Block]

The weighted-average assumptions used to determine the projected benefit obligation were as follows:


	Pension Benefit Plans
	U.S. Plans		Non-U.S. Plans		Other Postretirement Benefit Plans

December 31, 2020
Discount rate	2.32	%	1.80	%	1.36	%
Rate of compensation increase (1)	N/A		3.24	%	N/A
Interest crediting rate	4.10	%
December 31, 2019
Discount rate	3.20	%	2.39	%	2.70	%
Rate of compensation increase (1)	N/A		3.26	%	N/A
Interest crediting rate	4.10	%

Schedule of Net Benefit Costs [Table Text Block]

The components of net pension and other postretirement benefit costs reflected in Net income and other changes in plan assets and benefit obligations recognized in other comprehensive income were as follows:


	Pension Benefit Plans												Other Postretirement Benefit Plans
	U.S. Plans						Non-U.S. Plans
Year Ended December 31	2020		2019		2018		2020		2019		2018		2020		2019		2018
(in millions of U.S. dollars)
Costs reflected in Net income:
Service cost	$	—	$	49	$	57	$	4	$	11	$	12	$	1	$	—	$	1
Non-service cost:
Interest cost	99		118		105		22		27		27		2		4		3
Expected return on plan assets	(224)		(189)		(212)		(41)		(45)		(50)		(5)		(4)		(5)
Amortization of net actuarial loss	—		—		—		2		3		1		—		—		—
Amortization of prior service cost	—		—		—		—		—		—		(83)		(84)		(85)
Curtailments	—		—		—		(1)		(1)		—		—		—		(2)
Settlements	3		2		2		—		1		3		—		—		—
Total non-service benefit	(122)		(69)		(105)		(18)		(15)		(19)		(86)		(84)		(89)
Net periodic benefit	$	(122)	$	(20)	$	(48)	$	(14)	$	(4)	$	(7)	$	(85)	$	(84)	$	(88)
Changes in plan assets and benefit obligations recognized in other comprehensive income
Net actuarial loss (gain)	$	102	$	(4)	$	214	$	56	$	6	$	34	$	(2)	$	(2)	$	(11)
Prior service cost (benefit)	—		—		—		—		1		3		—		—		—
Amortization of net actuarial loss	—		—		—		(2)		(3)		(1)		—		—		(1)
Amortization of prior service cost	—		—		—		(1)		—		—		83		84		85
Curtailments	—		—		—		(1)		(3)		—		—		—		3
Settlements	(3)		(2)		(2)		—		(1)		(3)		—		—		—
Total decrease (increase) in other comprehensive income	$	99	$	(6)	$	212	$	52	$	—	$	33	$	81	$	82	$	76

The line items in which the service and non-service cost components of net periodic (benefit) cost are included in the Consolidated statements of operations were as follows:


	Pension Benefit Plans						Other Postretirement Benefit Plans
Year Ended December 31	2020		2019		2018		2020		2019		2018
(in millions of U.S. dollars)
Service cost:
Losses and loss expenses	$	—	$	6	$	7	$	—	$	—	$	—
Administrative expenses	4		54		62		1		—		1
Total service cost	4		60		69		1		—		1
Non-service cost:
Losses and loss expenses	(12)		(7)		(10)		(9)		(8)		(9)
Administrative expenses	(128)		(77)		(114)		(77)		(76)		(80)
Total non-service benefit	(140)		(84)		(124)		(86)		(84)		(89)
Net periodic benefit	$	(136)	$	(24)	$	(55)	$	(85)	$	(84)	$	(88)

Schedule of assumptions used, net periodic benefit costs [Table Text Block]

he weighted-average assumptions used to determine the net periodic pension and other postretirement benefit costs were as follows:


	Pension Benefit Plans
	U.S. Plans		Non-U.S. Plans		Other Postretirement Benefit Plans
Year Ended December 31
2020
Discount rate in effect for determining service cost	N/A		6.04	%	3.00	%
Discount rate in effect for determining interest cost	2.85	%	2.24	%	2.64	%
Rate of compensation increase	N/A		3.26	%	N/A
Expected long-term rate of return on plan assets	7.00	%	3.83	%	3.00	%
Interest crediting rate	4.10	%	N/A		N/A
2019
Discount rate in effect for determining service cost	4.23	%	4.48	%	4.04	%
Discount rate in effect for determining interest cost	3.94	%	2.88	%	3.69	%
Rate of compensation increase	4.00	%	3.37	%	N/A
Expected long-term rate of return on plan assets	7.00	%	4.40	%	3.00	%
Interest crediting rate	4.10	%	N/A		N/A
2018
Discount rate in effect for determining service cost	3.62	%	3.97	%	2.84	%
Discount rate in effect for determining interest cost	3.27	%	2.55	%	2.62	%
Rate of compensation increase	4.00	%	3.46	%	N/A
Expected long-term rate of return on plan assets	7.00	%	4.32	%	2.59	%
Interest crediting rate	4.10	%	N/A		N/A

Schedule of Health Care Cost Trend Rates [Table Text Block]

The weighted-average healthcare cost trend rate assumptions used to measure the expected cost of healthcare benefits were as follows:


	U.S. Plans						Non-U.S. Plans
	2020		2019		2018		2020		2019		2018
Healthcare cost trend rate	5.96	%	6.32	%	6.68	%	5.04	%	5.24	%	6.29	%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50	%	4.50	%	4.50	%	4.00	%	4.00	%	4.50	%
Year that the rate reaches the ultimate trend rate	2038		2038		2038		2040		2040		2029

Schedule of Allocation of Plan Assets [Table Text Block]

The following tables present the fair values of the pension plan assets, by valuation hierarchy. For additional information on how we classify these assets within the valuation hierarchy, refer to Note 4 to the Consolidated Financial Statements.


December 31, 2020	Pension Benefit Plans
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
U.S. Plans:
Short-term investments	$	59	$	—	$	—	$	59
U.S. Treasury / Agency	250		186		—		436
Non-U.S. and corporate bonds	—		793		—		793
Municipal	—		2		—		2
Equity securities	1,818		—		—		1,818
Total U.S. Plan assets (1)	$	2,127	$	981	$	—	$	3,108
Non-U.S. Plans:
Short-term investments	$	5	$	—	$	—	$	5
Non-U.S. and corporate bonds	—		609		—		609
Equity securities	127		388		—		515
Total Non-U.S. Plan assets (1)	$	132	$	997	$	—	$	1,129

(1)Excluded from the table above are $543 million and $147 million of other investments related to the U.S. Plans and Non-U.S. Plans, respectively, limited partnerships of $74 million and $8 million in U.S. Plans and Non-U.S. Plans, respectively, measured using NAV as a practical expedient, and $14 million in cash related to the U.S. Plans.


December 31, 2019	Pension Benefit Plans
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
U.S. Plans:
Short-term investments	$	18	$	37	$	—	$	55
U.S. Treasury / Agency	466		134		—		600
Non-U.S. and corporate bonds	—		749		—		749
Municipal	—		2		—		2
Equity securities	1,467		—		—		1,467
Total U.S. Plan assets (1)	$	1,951	$	922	$	—	$	2,873
Non-U.S. Plans:
Short-term investments	$	2	$	—	$	—	$	2
Non-U.S. and corporate bonds	—		598		—		598
Equity securities	112		318		—		430
Total Non-U.S. Plan assets (1)	$	114	$	916	$	—	$	1,030

(1)Excluded from the table above are $428 million and $107 million of other investments related to the U.S. Plans and Non-U.S. Plans, re

Schedule of expected future benefit payments

At December 31, 2020, our estimated expected future benefit payments are as follows:


	Pension Benefit Plans				Other Postretirement Benefit Plans
For the years ending December 31	U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
2021	$	159	$	30	$	19
2022	166		28		20
2023	171		30		16
2024	175		32		12
2025	180		32		7
2026-2030	947		185		5

Other (income) expense (Tables)

12 Months Ended

Dec. 31, 2020

Other Income and Expenses [Abstract]

Schedule of the components of Other (income) expense


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Equity in net income of partially-owned entities (1)	$	1,019	$	617	$	514
Gains (losses) from fair value changes in separate account assets (2)	58		44		(38)
Federal excise and capital taxes	(22)		(23)		(12)
Other	(61)		(42)		(30)
Total	$	994	$	596	$	434

(1) Equity in net income of partially-owned entities includes $167 million, $74 million, and $43 million attributable to our investments in Huatai (Huatai Group, Huatai P&C, and Huatai Life) for the years ended December 31, 2020, 2019, and 2018, respectively.

(2) Related to gains (losses) from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP.

Segment information (Tables)

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Operations By Segment


For the Year Ended December 31, 2020 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated
Net premiums written	$	14,474	$	4,920	$	1,846	$	9,335	$	731	$	2,514	$	—	$	—	$	33,820
Net premiums earned	13,964		4,866		1,822		9,285		698		2,482		—		—		33,117
Losses and loss expenses	10,129		3,187		1,544		5,255		435		724		435		1		21,710
Policy benefits	—		—		—		—		—		726		—		58		784
Policy acquisition costs	1,942		974		123		2,568		174		766		—		—		6,547
Administrative expenses	1,006		270		9		1,034		37		320		303		—		2,979
Underwriting income (loss)	887		435		146		428		52		(54)		(738)		(59)		1,097
Net investment income (loss)	2,061		260		30		534		307		385		(87)		(115)		3,375
Other (income) expense	23		5		1		13		2		(74)		(791)		(173)		(994)
Amortization expense of purchased intangibles	—		11		27		45		—		4		203		—		290
Segment income (loss)	$	2,925	$	679	$	148	$	904	$	357	$	401	$	(237)	$	(1)	$	5,176
Net realized gains (losses)													(499)		1		(498)
Interest expense													516		—		516
Income tax expense													629		—		629
Net income (loss)													$	(1,881)	$	—	$	3,533


For the Year Ended December 31, 2019 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated
Net premiums written	$	13,375	$	4,787	$	1,810	$	9,262	$	649	$	2,392	$	—	$	—	$	32,275
Net premiums earned	12,922		4,694		1,795		8,882		654		2,343		—		—		31,290
Losses and loss expenses	8,206		3,043		1,616		4,606		352		757		158		(8)		18,730
Policy benefits	—		—		—		—		—		696		—		44		740
Policy acquisition costs	1,831		948		84		2,501		169		620		—		—		6,153
Administrative expenses	1,028		286		6		1,033		35		323		319		—		3,030
Underwriting income (loss)	1,857		417		89		742		98		(53)		(477)		(36)		2,637
Net investment income (loss)	2,109		258		30		588		279		373		(125)		(86)		3,426
Other (income) expense	24		3		1		12		1		(48)		(459)		(130)		(596)
Amortization expense of purchased intangibles	—		12		28		45		—		2		218		—		305
Segment income (loss)	$	3,942	$	660	$	90	$	1,273	$	376	$	366	$	(361)	$	8	$	6,354
Net realized gains (losses) including OTTI													(522)		(8)		(530)
Interest expense													552		—		552
Chubb integration expenses													23		—		23
Income tax expense													795		—		795
Net income (loss)													$	(2,253)	$	—	$	4,454


For the Year Ended December 31, 2018 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated
Net premiums written	$	12,485	$	4,674	$	1,577	$	8,902	$	671	$	2,270	$	—	$	—	$	30,579
Net premiums earned	12,402		4,593		1,569		8,612		670		2,218		—		—		30,064
Losses and loss expenses	8,000		3,229		1,114		4,429		479		766		53		(3)		18,067
Policy benefits	—		—		—		—		—		628		—		(38)		590
Policy acquisition costs	1,829		939		79		2,346		162		557		—		—		5,912
Administrative expenses	966		269		(9)		1,014		41		310		295		—		2,886
Underwriting income (loss)	1,607		156		385		823		(12)		(43)		(348)		41		2,609
Net investment income (loss)	2,061		236		28		622		289		341		(209)		(63)		3,305
Other (income) expense	3		1		2		3		—		(12)		(406)		(25)		(434)
Amortization expense of purchased intangibles	—		13		28		41		—		2		255		—		339
Segment income (loss)	$	3,665	$	378	$	383	$	1,401	$	277	$	308	$	(406)	$	3	$	6,009
Net realized gains (losses) including OTTI													(649)		(3)		(652)
Interest expense													641		—		641
Chubb integration expenses													59		—		59
Income tax expense													695		—		695
Net income (loss)													$	(2,450)	$	—	$	3,962

Net Premiums Earned For Segment By Product

The following table presents net premiums earned for each segment by line of business:



	For the Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
North America Commercial P&C Insurance
Property & other short-tail lines	$	2,423	$	1,987	$	1,861
Casualty & all other	10,812		10,136		9,773
A&H	729		799		768
Total North America Commercial P&C Insurance	13,964		12,922		12,402
North America Personal P&C Insurance
Personal automobile	822		829		803
Personal homeowners	3,327		3,183		3,127
Personal other	717		682		663
Total North America Personal P&C Insurance	4,866		4,694		4,593
North America Agricultural Insurance	1,822		1,795		1,569
Overseas General Insurance
Property & other short-tail lines	2,468		2,244		2,134
Casualty & all other	2,738		2,494		2,429
Personal lines	1,981		1,896		1,784
A&H	2,098		2,248		2,265
Total Overseas General Insurance	9,285		8,882		8,612
Global Reinsurance
Property	104		131		123
Property catastrophe	173		142		170
Casualty & all other	421		381		377
Total Global Reinsurance	698		654		670
Life Insurance
Life	1,317		1,101		1,022
A&H	1,165		1,242		1,196
Total Life Insurance	2,482		2,343		2,218
Total net premiums earned	$	33,117	$	31,290	$	30,064

Net Premiums Earned by Geographic Region


	North America		Europe (1)		Asia Pacific / Far East		Latin America
2020	70	%	11	%	12	%	7	%
2019	70	%	11	%	12	%	7	%
2018	70	%	11	%	12	%	7	%

Earnings per share (Tables)

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Schedule Of Earnings Per Share, Basic And Diluted


	Year Ended December 31
(in millions of U.S. dollars, except share and per share data)	2020		2019		2018
Numerator:
Net income	$	3,533	$	4,454	$	3,962
Denominator:
Denominator for basic earnings per share:
Weighted-average shares outstanding	451,602,820		455,910,463		463,629,203
Denominator for diluted earnings per share:
Share-based compensation plans	1,838,692		3,004,200		3,173,145
Weighted-average shares outstanding and assumed conversions	453,441,512		458,914,663		466,802,348
Basic earnings per share	$	7.82	$	9.77	$	8.55
Diluted earnings per share	$	7.79	$	9.71	$	8.49
Potential anti-dilutive share conversions	6,811,966		2,410,337		3,543,188

Related Party Disclosures (Tables)

12 Months Ended

Dec. 31, 2020

Transactions generated under Starr agreements were as follows:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Consolidated statement of operations
Gross premiums written	$	507	$	394	$	411
Ceded premiums written	$	253	$	207	$	188
Commissions paid	$	97	$	77	$	84
Commissions received	$	59	$	46	$	42
Losses and loss expenses	$	170	$	185	$	188
Consolidated balance sheets
Reinsurance recoverable on losses and loss expenses	$	432	$	440
Ceded reinsurance premium payable	$	80	$	56

ABR Re

We own 15.6 percent of the common equity of ABR Reinsurance Capital Holdings Ltd. and warrants to acquire 0.5 percent of additional equity. ABR Reinsurance Capital Holdings Ltd., is the parent company of ABR Reinsurance Ltd. (ABR Re), an independent reinsurance company. Through long-term arrangements, Chubb will be the sole source of reinsurance risks ceded to ABR Re, and BlackRock, Inc. will be ABR Re’s exclusive investment management service provider. As an investor, Chubb is expected to benefit from underwriting profit generated by ABR Re’s reinsuring a wide range of Chubb’s primary insurance business and the income and capital appreciation BlackRock, Inc. seeks to deliver through its investment management services. In addition, Chubb has entered into an arrangement with BlackRock, Inc. under which both Chubb and BlackRock, Inc. will be entitled to an equal share of the aggregate amount of certain fees, including underwriting and investment management performance related fees, in connection with their respective reinsurance and investment management arrangements with ABR Re.

ABR Re is a variable interest entity; however, Chubb is not the primary beneficiary and does not consolidate ABR Re because Chubb does not have the power to control and direct ABR Re’s most significant activities, including investing and underwriting. Our minority ownership interest is accounted for under the equity method of accounting. Chubb cedes premiums to ABR Re and recognizes the associated commissions.

Transactions generated under ABR Re agreements were as follows:


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Consolidated statement of operations
Ceded premiums written	$	350	$	321	$	329
Commissions received	$	100	$	92	$	96

Consolidated balance sheets
Reinsurance recoverable on losses and loss expenses	$	806	$	674
Ceded reinsurance premium payable	$	67	$	62

Statutory Financial Information (Tables)

12 Months Ended

Dec. 31, 2020

Statutory Financial Information [Abstract]

Schedule of combined statutory capital and surplus and statutory net income (loss)


	December 31
(in millions of U.S. dollars)	2020		2019
Statutory capital and surplus
Property and casualty	$	45,964	$	43,077
Life	$	1,641	$	1,573


	Year Ended December 31
(in millions of U.S. dollars)	2020		2019		2018
Statutory net income (loss)
Property and casualty	$	4,294	$	6,046	$	7,521
Life	$	(247)	$	(210)	$	(102)

Tabular disclosure of how the entity's reporting under GAAP as of the balance sheet date differs from the results based on prescribed and permitted accounting practices of the state or country of domicile in which a relevant statutory filing is made, or differences in results based on the National Association of Insurance Commissioners (NAIC) prescribed practices, or a combination thereof. Describes the accounting practices used and the related monetary effect on statutory surplus, net income, and risk-based capital. If an insurance enterprise's risk-based capital would have triggered a regulatory event had it not used a permitted practice, that fact is disclosed in the financial statements. Permitted statutory accounting practices include practices not prescribed but allowed by the domiciliary state insurance department regulatory authority.

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]

Information provided in connection with outstanding debt of subsidiaries (Tables)

12 Months Ended

Dec. 31, 2020

Condensed Consolidating Balance Sheet

Condensed Consolidating Balance Sheet at December 31, 2020


(in millions of U.S. dollars)	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
Assets
Investments	$	—	$	197	$	118,472	$	—	$	118,669
Cash (1)	84		1		1,934		(272)		1,747
Restricted Cash	—		—		89		—		89
Insurance and reinsurance balances receivable	—		—		13,926		(3,446)		10,480
Reinsurance recoverable on losses and loss expenses	—		—		25,217		(9,625)		15,592
Reinsurance recoverable on policy benefits	—		—		299		(93)		206
Value of business acquired	—		—		263		—		263
Goodwill and other intangible assets	—		—		21,211		—		21,211
Investments in subsidiaries	56,148		55,231		—		(111,379)		—
Due from subsidiaries and affiliates, net	3,522		—		171		(3,693)		—

Other assets	10		463		23,921		(1,877)		22,517
Total assets	$	59,764	$	55,892	$	205,503	$	(130,385)	$	190,774
Liabilities
Unpaid losses and loss expenses	$	—	$	—	$	77,180	$	(9,369)	$	67,811
Unearned premiums	—		—		18,853		(1,201)		17,652
Future policy benefits	—		—		5,806		(93)		5,713
Due to subsidiaries and affiliates, net	—		3,008		685		(3,693)		—
Affiliated notional cash pooling programs(1)	—		272		—		(272)		—
Repurchase agreements	—		—		1,405		—		1,405

Long-term debt	—		14,948		—		—		14,948
Trust preferred securities	—		308		—		—		308
Other liabilities	323		1,418		26,133		(4,378)		23,496
Total liabilities	323		19,954		130,062		(19,006)		131,333
Total shareholders’ equity	59,441		35,938		75,441		(111,379)		59,441
Total liabilities and shareholders’ equity	$	59,764	$	55,892	$	205,503	$	(130,385)	$	190,774

(1) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Balance Sheet at December 31, 2019


(in millions of U.S. dollars)	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
Assets
Investments	$	—	$	1,013	$	108,221	$	—	$	109,234
Cash (1)	2		442		1,093		—		1,537
Restricted Cash	—		—		109		—		109
Insurance and reinsurance balances receivable	—		—		12,920		(2,563)		10,357
Reinsurance recoverable on losses and loss expenses	—		—		24,780		(9,599)		15,181
Reinsurance recoverable on policy benefits	—		—		292		(95)		197
Value of business acquired	—		—		306		—		306
Goodwill and other intangible assets	—		—		21,359		—		21,359
Investments in subsidiaries	50,853		52,076		—		(102,929)		—
Due from subsidiaries and affiliates, net	4,776		—		—		(4,776)		—
Other assets	12		408		20,072		(1,829)		18,663
Total assets	$	55,643	$	53,939	$	189,152	$	(121,791)	$	176,943
Liabilities
Unpaid losses and loss expenses	$	—	$	—	$	71,916	$	(9,226)	$	62,690
Unearned premiums	—		—		17,978		(1,207)		16,771
Future policy benefits	—		—		5,468		(95)		5,373
Due to subsidiaries and affiliates, net	—		4,446		330		(4,776)		—

Repurchase agreements	—		—		1,416		—		1,416
Short-term debt	—		1,298		1		—		1,299
Long-term debt	—		13,559		—		—		13,559
Trust preferred securities	—		308		—		—		308
Other liabilities	312		1,649		21,793		(3,558)		20,196
Total liabilities	312		21,260		118,902		(18,862)		121,612
Total shareholders’ equity	55,331		32,679		70,250		(102,929)		55,331
Total liabilities and shareholders’ equity	$	55,643	$	53,939	$	189,152	$	(121,791)	$	176,943

(1)Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.

Condensed Consolidating Statement Of Operations and Comprehensive Income

Condensed Consolidating Statements of Operations and Comprehensive Income


For the Year Ended December 31, 2020	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net premiums written	$	—	$	—	$	33,820	$	—	$	33,820
Net premiums earned	—		—		33,117		—		33,117
Net investment income	(1)		6		3,370		—		3,375
Equity in earnings of subsidiaries	3,457		2,052		—		(5,509)		—
Net realized gains (losses)	20		(397)		(121)		—		(498)
Losses and loss expenses	—		—		21,710		—		21,710
Policy benefits	—		—		784		—		784
Policy acquisition costs and administrative expenses	94		(130)		9,562		—		9,526
Interest (income) expense	(136)		596		56		—		516
Other (income) expense	(39)		(24)		(931)		—		(994)
Amortization of purchased intangibles	—		—		290		—		290

Income tax expense (benefit)	24		(181)		786		—		629
Net income	$	3,533	$	1,400	$	4,109	$	(5,509)	$	3,533
Comprehensive income	$	5,783	$	3,236	$	6,512	$	(9,748)	$	5,783

Condensed Consolidating Statements of Operations and Comprehensive Income


For the Year Ended December 31, 2019	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net premiums written	$	—	$	—	$	32,275	$	—	$	32,275
Net premiums earned	—		—		31,290		—		31,290
Net investment income	1		(15)		3,440		—		3,426
Equity in earnings of subsidiaries	4,307		3,022		—		(7,329)		—
Net realized gains (losses) including OTTI	(17)		(31)		(482)		—		(530)
Losses and loss expenses	—		—		18,730		—		18,730
Policy benefits	—		—		740		—		740
Policy acquisition costs and administrative expenses	92		(26)		9,117		—		9,183
Interest (income) expense	(243)		705		90		—		552
Other (income) expense	(27)		6		(575)		—		(596)
Amortization of purchased intangibles	—		—		305		—		305
Chubb integration expenses	1		2		20		—		23
Income tax expense (benefit)	14		(175)		956		—		795
Net income	$	4,454	$	2,464	$	4,865	$	(7,329)	$	4,454
Comprehensive income	$	7,521	$	4,988	$	7,922	$	(12,910)	$	7,521

Condensed Consolidating Statements of Operations and Comprehensive Income (Loss)


For the Year Ended December 31, 2018	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net premiums written	$	—	$	—	$	30,579	$	—	$	30,579
Net premiums earned	—		—		30,064		—		30,064
Net investment income	6		13		3,286		—		3,305
Equity in earnings of subsidiaries	3,753		2,578		—		(6,331)		—
Net realized gains (losses) including OTTI	—		117		(769)		—		(652)
Losses and loss expenses	—		—		18,067		—		18,067
Policy benefits	—		—		590		—		590
Policy acquisition costs and administrative expenses	87		(58)		8,769		—		8,798
Interest (income) expense	(299)		806		134		—		641
Other (income) expense	(24)		26		(436)		—		(434)
Amortization of purchased intangibles	—		—		339		—		339
Chubb integration expenses	14		1		44		—		59
Income tax expense (benefit)	19		(148)		824		—		695
Net income	$	3,962	$	2,081	$	4,250	$	(6,331)	$	3,962
Comprehensive income (loss)	$	1,242	$	(27)	$	1,808	$	(1,781)	$	1,242

Condensed Consolidating Statement of Cash Flows


For the Year Ended December 31, 2020	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net cash flows from operating activities	$	1,933	$	274	$	10,788	$	(3,210)	$	9,785
Cash flows from investing activities
Purchases of fixed maturities available for sale	—		(49)		(26,249)		—		(26,298)
Purchases of fixed maturities held to maturity	—		—		(202)		—		(202)
Purchases of equity securities	—		—		(6,419)		—		(6,419)
Sales of fixed maturities available for sale	—		9		11,368		—		11,377
Sales of equity securities	—		—		3,880		—		3,880
Maturities and redemptions of fixed maturities available for sale	—		50		12,400		—		12,450
Maturities and redemptions of fixed maturities held to maturity	—		—		995		—		995
Net change in short-term investments	—		772		(853)		—		(81)
Net derivative instruments settlements	—		55		(168)		—		(113)


Private equity contributions	—		—		(1,924)		—		(1,924)
Private equity distributions	—		—		907		—		907
Payment, including deposit, for Huatai Group interest	—		—		(1,623)		—		(1,623)

Capital contribution	(1,200)		(72)		—		1,272		—

Other	(2)		4		(472)		—		(470)
Net cash flows from (used for) investing activities	(1,202)		769		(8,360)		1,272		(7,521)
Cash flows from financing activities
Dividends paid on Common Shares	(1,388)		—		—		—		(1,388)
Common Shares repurchased	(523)		—		—		—		(523)
Proceeds from issuance of long-term debt	—		988		—		—		988
Proceeds from issuance of repurchase agreements	—		—		2,354		—		2,354
Repayment of long-term debt	—		(1,301)		—		—		(1,301)
Repayment of repurchase agreements	—		—		(2,354)		—		(2,354)
Proceeds from share-based compensation plans	—		—		145		—		145
Advances (to) from affiliates	1,265		(1,438)		173		—		—
Dividends to parent company	—		—		(3,210)		3,210		—
Capital contribution	—		—		1,272		(1,272)		—
Net proceeds from affiliated notional cash pooling programs(1)	—		272		—		(272)		—
Policyholder contract deposits and other	—		—		470		—		470
Policyholder contract withdrawals and other	—		—		(386)		—		(386)
Other	—		—		(87)		—		(87)
Net cash flows used for financing activities	(646)		(1,479)		(1,623)		1,666		(2,082)
Effect of foreign currency rate changes on cash and restricted cash	(3)		(5)		16		—		8
Net increase (decrease) in cash and restricted cash	82		(441)		821		(272)		190
Cash and restricted cash – beginning of year (1)	2		442		1,202		—		1,646
Cash and restricted cash – end of year (1)	$	84	$	1	$	2,023	$	(272)	$	1,836

(1)Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Statement of Cash Flows


For the Year Ended December 31, 2019	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net cash flows from operating activities	$	412	$	2,926	$	6,878	$	(3,874)	$	6,342
Cash flows from investing activities
Purchases of fixed maturities available for sale	—		(21)		(25,825)		—		(25,846)

Purchases of fixed maturities held to maturity	—		—		(229)		—		(229)
Purchases of equity securities	—		—		(531)		—		(531)
Sales of fixed maturities available for sale	—		1		13,115		—		13,116

Sales of equity securities	—		—		611		—		611
Maturities and redemptions of fixed maturities available for sale	—		41		8,998		—		9,039
Maturities and redemptions of fixed maturities held to maturity	—		—		946		—		946
Net change in short-term investments	—		(808)		(309)		—		(1,117)
Net derivative instruments settlements	—		(74)		(629)		—		(703)
Private equity contributions	—		—		(1,315)		—		(1,315)
Private equity distributions	—		—		1,390		—		1,390
Capital contribution	(1,000)		(110)		—		1,110		—
Acquisition of subsidiaries (net of cash acquired of $45)	—		—		(29)		—		(29)
Payment, including deposit, for Huatai Group interest	—		—		(580)		—		(580)

Other	—		(4)		(653)		—		(657)
Net cash flows used for investing activities	(1,000)		(975)		(5,040)		1,110		(5,905)
Cash flows from financing activities
Dividends paid on Common Shares	(1,354)		—		—		—		(1,354)
Common Shares repurchased	(327)		—		(1,203)		—		(1,530)
Proceeds from issuance of long-term debt	—		2,828		—		—		2,828
Proceeds from issuance of repurchase agreements	—		—		2,817		—		2,817
Repayment of long-term debt	—		(500)		(10)		—		(510)
Repayment of repurchase agreements	—		—		(2,817)		—		(2,817)
Proceeds from share-based compensation plans	—		—		204		—		204
Advances (to) from affiliates	2,301		(3,223)		922		—		—
Dividends to parent company	—		—		(3,874)		3,874		—
Capital contribution	—		—		1,110		(1,110)		—
Net proceeds payments to affiliated notional cash pooling programs(1)	(35)		(617)		—		652		—
Policyholder contract deposits	—		—		514		—		514
Policyholder contract withdrawals	—		—		(303)		—		(303)

Net cash flows from (used for) financing activities	585		(1,512)		(2,640)		3,416		(151)
Effect of foreign currency rate changes on cash and restricted cash	4		1		15		—		20
Net increase (decrease) in cash and restricted cash	1		440		(787)		652		306
Cash and restricted cash – beginning of year (1)	1		2		1,989		(652)		1,340
Cash and restricted cash – end of year (1)	$	2	$	442	$	1,202	$	—	$	1,646

(1)Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Statement of Cash Flows


For the Year Ended December 31, 2018	Chubb Limited (Parent Guarantor)		Chubb INA Holdings Inc. (Subsidiary Issuer)		Other Chubb Limited Subsidiaries		Consolidating Adjustments and Eliminations		Chubb Limited Consolidated
(in millions of U.S. dollars)
Net cash flows from operating activities	$	256	$	4,654	$	5,878	$	(5,308)	$	5,480
Cash flows from investing activities
Purchases of fixed maturities available for sale	—		(38)		(24,697)		—		(24,735)

Purchases of fixed maturities held to maturity	—		—		(456)		—		(456)
Purchases of equity securities	—		—		(207)		—		(207)
Sales of fixed maturities available for sale	—		11		14,019		—		14,030

Sales of equity securities	—		—		315		—		315
Maturities and redemptions of fixed maturities available for sale	—		17		7,335		—		7,352
Maturities and redemptions of fixed maturities held to maturity	—		—		1,124		—		1,124
Net change in short-term investments	—		3		513		—		516
Net derivative instruments settlements	—		(7)		23		—		16
Private equity contributions	—		—		(1,337)		—		(1,337)
Private equity distributions	—		—		980		—		980

Capital contribution	(1,475)		(3,550)		—		5,025		—
Other	—		(18)		(515)		—		(533)
Net cash flows used for investing activities	(1,475)		(3,582)		(2,903)		5,025		(2,935)
Cash flows from financing activities
Dividends paid on Common Shares	(1,337)		—		—		—		(1,337)
Common Shares repurchased	—		—		(1,044)		—		(1,044)
Proceeds from issuance of long-term debt	—		2,171		—		—		2,171
Proceeds from issuance of repurchase agreements	—		—		2,029		—		2,029
Repayment of long-term debt	—		(2,000)		(1)		—		(2,001)
Repayment of repurchase agreements	—		—		(2,019)		—		(2,019)
Proceeds from share-based compensation plans	—		—		115		—		115
Advances (to) from affiliates	2,519		(1,744)		(775)		—		—
Dividends to parent company	—		—		(5,308)		5,308		—
Capital contribution	—		—		5,025		(5,025)		—
Net payments to affiliated notional cash pooling programs(1)	35		502		—		(537)		—
Policyholder contract deposits	—		—		453		—		453
Policyholder contract withdrawals	—		—		(358)		—		(358)

Net cash flows from (used for) financing activities	1,217		(1,071)		(1,883)		(254)		(1,991)
Effect of foreign currency rate changes on cash and restricted cash	—		—		(65)		—		(65)
Net increase (decrease) in cash and restricted cash	(2)		1		1,027		(537)		489
Cash and restricted cash – beginning of year (1)	3		1		962		(115)		851
Cash and restricted cash – end of year (1)	$	1	$	2	$	1,989	$	(652)	$	1,340

(1)Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018 and 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Summary of significant accounting policies (Narrative) (Detail) - USD ($) $ in Millions		12 Months Ended
	Jan. 14, 2016	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deposit Assets		$ 107	$ 93
Unpaid losses and loss expenses		67,811	62,690	$ 62,960	$ 63,179
Deposit liabilities included in Deposit liabilities		86	88
Borrowings under Guaranteed Investment Agreements		2,200	2,000
Summary of significant accounting policies [Line Items]
Deferred Policy Acquisition Costs, Amortization Expense		6,547	6,153	5,912
Deferred Advertising Costs		$ 226	246
Deferred Marketing Costs, Amortization Period		10 years
Recoverable from unrated reinsurers, ceded reserve, default factor (percent)		34.00%
Percentage of fair value of loaned securities		102.00%
Quality assessment threshold used in goodwill impairment testing		50.00%
Net operating results of ESIS included within Administrative expenses		$ 18	47	49
Property, Plant and Equipment, Net		2,000	1,900
Chubb integration expenses		0	23	59
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent		(59,441)	(55,331)	(50,312)
The Chubb Corporation [Member] \| Debt Securities [Member]
Summary of significant accounting policies [Line Items]
Assets, Fair Value Adjustment	$ 1,652	213
Selling and Marketing Expense [Member]
Summary of significant accounting policies [Line Items]
Deferred Policy Acquisition Costs, Amortization Expense		99	109	114
Fair Value Adjustment to Acquired Loss Reserves [Member] \| The Chubb Corporation [Member]
Summary of significant accounting policies [Line Items]
Balance of FV adjustment on Unpaid Losses and Loss Expenses		110	145
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent		$ (39,337)	$ (36,142)	(31,700)	(27,474)
Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability for Future Policy Benefits, Interest Rate		1.00%	1.00%
Summary of significant accounting policies [Line Items]
Reinsurance Premiums, Amortization Period		1 year
Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Liability for Future Policy Benefits, Interest Rate		9.00%	11.00%
Summary of significant accounting policies [Line Items]
Reinsurance Premiums, Amortization Period		3 years
Finite-Lived Intangible Asset, Useful Life		25 years
Affiliated notional cash pooling program		$ 300
Structured settlements
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deposit Assets		26	$ 31
Unpaid losses and loss expenses		548
Reinsurance recoverables for amounts due from life insurance companies		522
Short-Duration Insurance, Other [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Unpaid losses and loss expenses		42	43
Software Development [Member]
Summary of significant accounting policies [Line Items]
Property, Plant and Equipment, Net		$ 1,300
Property, Plant and Equipment, Useful Life		15 years
Software Development [Member] \| Minimum
Summary of significant accounting policies [Line Items]
Property, Plant and Equipment, Useful Life		3 years
Software Development [Member] \| Maximum
Summary of significant accounting policies [Line Items]
Property, Plant and Equipment, Useful Life		5 years
Building [Member]
Summary of significant accounting policies [Line Items]
Property, Plant and Equipment, Net		$ 260
Building [Member] \| Maximum
Summary of significant accounting policies [Line Items]
Property, Plant and Equipment, Useful Life		40 years
Cumulative Effect, Period of Adoption, Adjustment [Member] \| Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent			72	$ 12	$ (264)
Cumulative effect on retained earnings, before tax [Member] \| Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent			$ 79

Summary of significant accounting policies Summary of Significant Accounting Policies - Cash (Details) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

^[5]

Cash and Cash Equivalents [Line Items]

$ 1,747

^[1]

$ 1,537

^[2]

$ 1,247

89

109

93

Cash and restricted cash

$ 1,836

^[3]

$ 1,646

^[3],[4]

$ 1,340

^[3],[5]

$ 851

[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.
[3]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[4]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[5]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018 and 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Acquisitions (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Acquisitions (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investment [Line Items]
Payment, including deposit, for Huatai Group Interest			$ 1,623	$ 580
Banchile Seguros de Vida [Member]
Investment [Line Items]
Payments to Acquire Businesses, Gross	$ 74
Huatai Group [Member]
Investment [Line Items]
Ownership Percentage	47.10%		47.10%
Huatai Group [Member] \| CHINA
Investment [Line Items]
Equity method investment, additional 7.1 percentage obtained			7.10%
Portion two of payments to acquire equity method investments			$ 493
Portion one of payments to acquire equity method investments				$ 1,100
Equity method investment, additional 15.3 ownership percentage obtained				15.30%
Equity method investment, additional 22.4 ownership percentage obtained				22.40%
Ownership Percentage	47.00%		47.00%	31.00%
Equity method investment, incremental 0.9 percent obtained	0.90%
Purchase of incremental ownership interest	$ 65
Payment, including deposit, for Huatai Group Interest			$ 1,623	$ 580	$ 0
Huatai Group [Member] \| Subsequent Event [Member] \| CHINA
Investment [Line Items]
Equity method investment, additional 7.1 percentage obtained		7.10%

Investments (Narrative) (Detail) $ in Millions	12 Months Ended
Investments (Narrative) (Detail) $ in Millions	Dec. 31, 2021	Dec. 31, 2020 USD ($) partnerships	Dec. 31, 2019 USD ($)
Investment [Line Items]
Document Period End Date		Dec. 31, 2020
Limited partnerships number \| partnerships		130
Restricted assets in fixed maturities and short-term investments		$ 19,600	$ 21,000
Restricted assets in cash		89	$ 109
Debt Securities, Available-for-sale, Purchased with Credit Deterioration, Amount at Purchase Price		108
Debt Securities, Available-for-sale, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date		5
Debt Securities, Available-for-sale, Purchased with Credit Deterioration, Amount at Par Value		$ 144
Huatai Group [Member]
Investment [Line Items]
Ownership Percentage		47.10%
CHINA \| Huatai Group [Member]
Investment [Line Items]
Ownership Percentage		47.00%	31.00%
Equity method investment, additional 15.3 ownership percentage obtained			15.30%
Equity method investment, additional 7.1 percentage obtained		7.10%
CHINA \| Huatai Life Insurance Co. [Member]
Investment [Line Items]
Ownership Percentage		20.00%	20.00%
Subsequent Event [Member] \| CHINA \| Huatai Group [Member]
Investment [Line Items]
Equity method investment, additional 7.1 percentage obtained	7.10%
Indirect Ownership [Member] \| CHINA \| Huatai Life Insurance Co. [Member]
Investment [Line Items]
Ownership Percentage		37.50%
Direct Ownership [Member] \| CHINA \| Huatai Life Insurance Co. [Member]
Investment [Line Items]
Ownership Percentage		20.00%

Investments Investments (Schedule Of Amortized Cost and Fair Value of Available-for-sale Securities and Related OTTI Recognized in AOCI) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 85,188	$ 82,580
Debt Securities, Available-for-sale, Allowance for Credit Loss	20	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	5,655	3,074
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(124)	(166)
Available for sale, Fair Value	90,699	85,488
Available for sale, OTTI recognized in AOCI		(30)
US Treasury and Government [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,471	3,188
Debt Securities, Available-for-sale, Allowance for Credit Loss	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	199	96
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	(1)
Available for sale, Fair Value	2,670	3,283
Available for sale, OTTI recognized in AOCI		0
Foreign
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	24,594	22,670
Debt Securities, Available-for-sale, Allowance for Credit Loss	(6)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,808	1,099
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(42)	(62)
Available for sale, Fair Value	26,354	23,707
Available for sale, OTTI recognized in AOCI		(25)
Corporate securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	34,095	30,689
Debt Securities, Available-for-sale, Allowance for Credit Loss	(14)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	2,322	1,180
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(72)	(78)
Available for sale, Fair Value	36,331	31,791
Available for sale, OTTI recognized in AOCI		(5)
Collateralized Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	17,456	18,712
Debt Securities, Available-for-sale, Allowance for Credit Loss	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,022	494
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(8)	(14)
Available for sale, Fair Value	18,470	19,192
Available for sale, OTTI recognized in AOCI		0
States, municipalities, and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	6,572	7,321
Debt Securities, Available-for-sale, Allowance for Credit Loss	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	304	205
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(2)	(11)
Available for sale, Fair Value	$ 6,874	7,515
Available for sale, OTTI recognized in AOCI		$ 0

Investments (Schedule Of Amortized Cost And Fair Value Of Held-to-Maturity And Related Other-Than-Temporary Impairment Recognized In Accumulated Other Comprehensive Income) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	$ 11,697	$ 12,581
Debt Securities, Held-to-maturity, Allowance for Credit Loss	44	0
Debt securities, held to maturity, net carrying value	11,653
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	859	427
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(2)	(3)
Held to maturity, Fair Value	12,510	13,005
Held to maturity, OTTI recognized in AOCI		0
U.S. Treasury and agency
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	1,392	1,318
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0
Debt securities, held to maturity, net carrying value	1,392
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	60	29
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	0
Held to maturity, Fair Value	1,452	1,347
Held to maturity, OTTI recognized in AOCI		0
Foreign
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	1,295	1,423
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(7)
Debt securities, held to maturity, net carrying value	1,288
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	118	62
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(1)	0
Held to maturity, Fair Value	1,405	1,485
Held to maturity, OTTI recognized in AOCI		0
Corporate securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	2,185	2,349
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(35)
Debt securities, held to maturity, net carrying value	2,150
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	288	121
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	(2)
Held to maturity, Fair Value	2,438	2,468
Held to maturity, OTTI recognized in AOCI		0
Mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	2,000	2,331
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(1)
Debt securities, held to maturity, net carrying value	1,999
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	148	65
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(1)	0
Held to maturity, Fair Value	2,146	2,396
Held to maturity, OTTI recognized in AOCI		0
States, municipalities, and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	4,825	5,160
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(1)
Debt securities, held to maturity, net carrying value	4,824
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	245	150
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	(1)
Held to maturity, Fair Value	$ 5,069	5,309
Held to maturity, OTTI recognized in AOCI		$ 0

Investments (Held-to-maturity credit quality indicator) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 11,697	$ 12,581
Fixed Maturities Percent of Total Amortized cost	100.00%
Standard & Poor's, AAA Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 2,511
Fixed Maturities Percent of Total Amortized cost	22.00%
Standard & Poor's, AA Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 6,193
Fixed Maturities Percent of Total Amortized cost	53.00%
Standard & Poor's, A Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 2,138
Fixed Maturities Percent of Total Amortized cost	18.00%
Standard & Poor's, BBB Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 826
Fixed Maturities Percent of Total Amortized cost	7.00%
Standard & Poor's, BB Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 28
Fixed Maturities Percent of Total Amortized cost	0.00%
Other [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 1
Fixed Maturities Percent of Total Amortized cost	0.00%

Investments (Schedule Of Fixed Maturities By Contractual Maturity) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Available for sale, Due in 1 year or less, Amortized Cost		$ 3,951
Available for sale, Due after 1 year through 5 years, Amortized Cost		27,142
Available for sale, Due after 5 years though 10 years, Amortized Cost		23,901
Available for sale, Due after 10 years, Amortized Cost		8,874
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost		63,868
Available for sale, Mortgage-backed securities, Amortized Cost		18,712
Debt Securities, Available-for-sale, Amortized Cost	$ 85,188	82,580
Available for sale, Due in 1 year or less, Fair Value	4,760	3,973
Available for sale, Due after 1 year through 5 years, Fair Value	26,227	27,720
Available for sale, Due after 5 years through 10 years, Fair Value	27,232	24,874
Available for sale, Due after 10 years, Fair Value	14,010	9,729
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	72,229	66,296
Available for sale, Mortgage backed securities, Fair Value	18,470	19,192
Available for sale, Fair Value	90,699	85,488
Held to maturity, Due in 1 year or less, Amortized Cost		478
Debt securities, Held-to-maturity, maturity, allocated and single maturity date, within on year, net carrying value	1,231
Held to maturity, Due after 1 year through 5 years, Amortized Cost		3,869
Debt securities, Held-to-maturity, maturity, allocated and single maturity date, after one through five years, net carrying value	3,592
Held to maturity, Due after 5 years through 10 years, Amortized Cost		3,756
Debt securities, Held-to-maturity, maturity, allocated and single maturity date, after five through ten years, net carrying value	3,029
Held to maturity, Due after 10 years, Amortized Cost		2,147
Debt securities, Held-to-maturity, maturity, allocated and single maturity date, after 10 years, net carrying value	1,802
Debt securities, Held-to-maturity, maturity, allocated and single maturity date, net carrying value	9,654
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Amortized Cost		10,250
Held to maturity, Mortgage backed securities, Amortized Cost		2,331
Debt securities, Held-to-maturity, without single maturity date, net carrying value	1,999
Debt Securities, Held-to-maturity	11,697	12,581
Held to maturity, Due in 1 year or less, Fair Value	1,240	479
Held to maturity, Due after 1 year through 5, Fair Value	3,760	3,940
Held to maturity, Due after 5 years through 10 years, Fair Value	3,228	3,883
Held to maturity, Due after 10 years, Fair Value	2,136	2,307
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Fair Value	10,364	10,609
Held to maturity, Mortgage backed securities, Fair Value	2,146	2,396
Debt securities, held to maturity, net carrying value	11,653
Held to maturity, Fair Value	$ 12,510	$ 13,005

Investments (Aggregate Fair Value And Gross Unrealized Loss By Length Of Time Security Has Continuously Been In Unrealized Loss Position) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Investment [Line Items]
Document Period End Date	Dec. 31, 2020
Fixed Maturities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 4,755	$ 5,563
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(75)	(81)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	758	3,337
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(22)	(88)
Debt Securities, Available-for-sale, Unrealized Loss Position	5,513	8,900
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(97)	(169)
U.S. Treasury and agency \| Fixed Maturities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		234
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		339
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Debt Securities, Available-for-sale, Unrealized Loss Position		573
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		(1)
Foreign \| Fixed Maturities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,628	1,846
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(35)	(34)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	114	802
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(5)	(28)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,742	2,648
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(40)	(62)
Corporate securities \| Fixed Maturities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,212	2,121
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(33)	(40)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	593	988
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(14)	(40)
Debt Securities, Available-for-sale, Unrealized Loss Position	2,805	3,109
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(47)	(80)
Mortgage-backed securities \| Fixed Maturities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	875	1,174
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(6)	(6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	35	932
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2)	(8)
Debt Securities, Available-for-sale, Unrealized Loss Position	910	2,106
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(8)	(14)
States, municipalities, and political subdivisions \| Fixed Maturities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	40	188
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	16	276
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	(12)
Debt Securities, Available-for-sale, Unrealized Loss Position	56	464
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (2)	$ (12)

Investments (Roll-Forward Of Pre-Tax Credit Losses Related To Fixed Maturities For Which Portion Of Other-Than-Temporary Impairment Was Recognized In Other Comprehensive Income) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Roll-Forward Of Pre-Tax Credit Losses Related To Fixed Maturities For Which Portion Of OTTI Was Recognized In OCI
Balance of credit losses related to securities still held-beginning of period	$ 34	$ 22
Additions where no OTTI was previously recorded	33	20
Additions where an OTTI was previously recorded	4	5
Reductions for securities sold during the period	(41)	(13)
Balance of credit losses related to securities still held-end of period	$ 30	$ 34

Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Other-than-temporary impairment (OTTI) losses gross

$ (90)

$ (52)

OTTI on Fixed Maturities

(58)

(49)

Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)

$ 188

Debt Securities, Available-For-Sale, Credit Impairment Charges Intent to Sell

(170)

0

Foreign exchange gains( losses)

(483)

7

131

Fair Value adjustment on insurance derivative

(202)

(4)

(248)

(228)

(585)

(330)

(498)

(530)

(652)

Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax

2,130

3,088

(1,699)

(462)

(647)

297

Other derivative instruments

Investment and embedded derivative instruments

1

(8)

(3)

81

(435)

(75)

S&P Options and Futures

Equity Securities [Member]

(108)

(138)

(4)

Fixed maturities held to maturity

586

104

(59)

^[1]

Other Investments [Member]

(24)

(31)

(38)

Available-for-sale Securities [Member]

(32)

(20)

(5)

2,628

3,769

(1,958)

Debt Securities [Member]

Other-than-temporary impairment (OTTI) losses gross

(90)

(52)

OTTI on fixed maturities recognized in OCI (pre-tax)

0

32

3

OTTI on Fixed Maturities

(58)

(49)

Fixed Maturities [Member]

Debt Securities, Available-for-sale, Realized Gain (Loss), Excluding Other-than-temporary Impairment

244

203

334

Debt Securities, Available-for-sale, Realized Loss, Excluding Other-than-temporary Impairment

(366)

(176)

(587)

Debt Securities, Available-for-sale, Realized Gain (Loss)

(281)

(31)

(302)

Other [Member]

Gain (Loss) on Sale of Other Investments

(60)

(5)

(87)

Accounting Standards Update 2016-01 [Member] | Equity Securities [Member]

(12)

(3)

0

586

104

(59)

131

46

(129)

Accounting Standards Update 2016-01 [Member] | Other Investments [Member]

455

58

70

(32)

(20)

(5)

(32)

(15)

(126)

Accounting Standards Update 2016-01 [Member] | Equity securities and other investments [Member]

0

(5)

121

554

84

(64)

99

31

(255)

Accounting Standards Update 2016-13 [Member]

455

53

191

Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)

$ 11

$ 0

[1]	Relates to certain securities we intended to sell and securities written to market entering default.

Investments Investments (Schedule of Gains and Losses on Equity and Other Investments) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

$ 2,130

$ 3,088

$ (1,699)

Equity Securities [Member]

(498)

(530)

(652)

Other Investments [Member]

586

104

(59)

^[1]

Accounting Standards Update 2016-01 [Member] | Equity Securities [Member]

(32)

(20)

(5)

586

104

(59)

131

46

(129)

Accounting Standards Update 2016-01 [Member] | Other Investments [Member]

455

58

70

(32)

(15)

(126)

0

(5)

121

Accounting Standards Update 2016-01 [Member] | Equity securities and other investments [Member]

(32)

(20)

(5)

99

31

(255)

455

53

191

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

$ 554

$ 84

$ (64)

[1]	Relates to certain securities we intended to sell and securities written to market entering default.

Investments (Schedule Of Other Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Other Investment Not Readily Marketable [Line Items]
Other Investments	$ 7,945	$ 6,062
Alternative Investment	6,770	4,921
Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	7,945	6,062
Alternative Investment	6,770	4,921
Other [Member] \| Other Accounting Method [Member] \| Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	188	234
Partially-owned Investment Companies [Member] \| Equity Method Investments [Member] \| Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	5,969	4,142
Limited Partner [Member] \| Cost-method Investments [Member] \| Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	547	508
Investment Funds [Member] \| Cost-method Investments [Member] \| Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	254	271
Life Insurance Product Line [Member] \| Other Accounting Method [Member] \| Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	438	377
Policy Loans [Member] \| Other Accounting Method [Member] \| Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	233	247
Non-qualified separate account assets [Member] \| Other Accounting Method [Member] \| Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	$ 316	$ 283

Investments (Rollforward of expected credit losses AFS) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 20	$ 0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	5
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	188
Debt Securities, Available-for-sale, Allowance for Credit Loss, Recovery	(193)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Writeoff	(5)
Accounting Standards Update 2016-13 [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss				$ 25
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	$ 11	$ 0	$ 0

Investments (Rollforward of expected credit losses HTM) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	$ 44		$ 0
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Period Increase (Decrease)	9
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Recovery	$ (9)
Accounting Standards Update 2016-13 [Member]
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss		$ 44

Investments Investments (Entities That Calculate Net Asset Value Per Share) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 3,200	$ 3,263
Alternative Investment	6,770	4,921
Financial [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	237	329
Alternative Investment	$ 673	$ 611
Financial [Member] \| Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Financial [Member] \| Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	10 years	10 years
Real Estate Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 598	$ 422
Alternative Investment	$ 805	$ 712
Real Estate Funds [Member] \| Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Real Estate Funds [Member] \| Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	11 years	11 years
Distressed Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 970	$ 80
Alternative Investment	$ 358	$ 263
Distressed Alternative Investments [Member] \| Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Distressed Alternative Investments [Member] \| Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	8 years	8 years
Private Credit Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 270	$ 272
Alternative Investment	$ 88	$ 104
Private Credit Alternative Investments [Member] \| Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	3 years	3 years
Private Credit Alternative Investments [Member] \| Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	8 years	8 years
Private Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 1,125	$ 2,160
Alternative Investment	$ 4,519	$ 2,844
Private Equity Funds [Member] \| Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Private Equity Funds [Member] \| Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	14 years	14 years
Vintage Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 0	$ 0
Alternative Investment	$ 73	$ 116
Vintage Alternative Investments [Member] \| Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	1 year	1 year
Vintage Alternative Investments [Member] \| Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Investment Funds Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 0	$ 0
Alternative Investment	$ 254	$ 271

Investments (Schedule Of Investments In Partially-Owned Insurance Companies) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investment [Line Items]
Document Period End Date	Dec. 31, 2020
Carrying Value	$ 2,813	$ 1,332
Goodwill	15,400	15,296	$ 15,271
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 1,385	527
Huatai Group [Member]
Investment [Line Items]
Ownership Percentage	47.10%
Huatai Group [Member] \| CHINA
Investment [Line Items]
Carrying Value	$ 2,461	$ 1,053
Ownership Percentage	47.00%	31.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 1,313	$ 460
Huatai Life Insurance Co. [Member] \| CHINA
Investment [Line Items]
Carrying Value	$ 201	$ 147
Ownership Percentage	20.00%	20.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 69	$ 64
Freisenbruch-Meyer \| Bermuda
Investment [Line Items]
Carrying Value	$ 10	$ 10
Ownership Percentage	40.00%	40.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 3	$ 3
Chubb Arabia Cooperative Insurance Company [Member] \| Saudi Arabia
Investment [Line Items]
Carrying Value	$ 23	$ 20
Ownership Percentage	30.00%	30.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 0	$ 0
Russian Reinsurance Company \| Russia
Investment [Line Items]
Carrying Value	$ 4	$ 2
Ownership Percentage	23.00%	23.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 0	$ 0
ABR Reinsurance Capital Holdings Ltd. [Member] \| Bermuda
Investment [Line Items]
Carrying Value	$ 114	$ 100
Ownership Percentage	15.60%	12.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 0	$ 0
Direct Ownership [Member] \| Huatai Life Insurance Co. [Member] \| CHINA
Investment [Line Items]
Ownership Percentage	20.00%
Indirect Ownership [Member] \| Huatai Life Insurance Co. [Member] \| CHINA
Investment [Line Items]
Ownership Percentage	37.50%
Total Direct and Indirect [Member] \| Huatai Life Insurance Co. [Member] \| CHINA
Investment [Line Items]
Ownership Percentage	57.50%

Investments (Schedule Of Sources Of Net Investment Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Investment Income [Line Items]
Gross investment income	$ 3,551	$ 3,598	$ 3,473
Investment expenses	(176)	(172)	(168)
Net investment income	3,375	3,426	3,305
Amortization of Debt Issuance Costs and Discounts	(367)	(395)	(592)
The Chubb Corporation [Member]
Net Investment Income [Line Items]
Amortization of Debt Issuance Costs and Discounts	(116)	(161)	(248)
Fixed Maturities [Member]
Net Investment Income [Line Items]
Gross investment income	3,321	3,385	3,128
Short-term investments
Net Investment Income [Line Items]
Gross investment income	48	84	90
Other interest income [Member]
Net Investment Income [Line Items]
Gross investment income	19	25	118
Equity securities
Net Investment Income [Line Items]
Gross investment income	81	26	33
Other Investments [Member]
Net Investment Income [Line Items]
Gross investment income	$ 82	$ 78	$ 104

Investments (Schedule Of Components Of Restricted Assets) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Funds Held under Reinsurance Agreements, Asset	$ 12,305	$ 14,004
Deposits with non-U.S. regulatory authorities	2,905	2,709
Collateral pledged under repurchase agreements	1,462	1,464
Deposits with U.S. regulatory authorities	2,438	2,466
Other pledged assets	584	490
Total restricted assets	$ 19,694	$ 21,133

Fair Value Measurements (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (228)	$ (585)	$ (330)
Accounts payable, accrued expenses, and other liabilities	14,052	12,214
Guaranteed Minimum Income Benefit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(202)	(4)	(248)
Accounts payable, accrued expenses, and other liabilities		441	409	$ 346
Fair Value, Inputs, Level 3 [Member] \| Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	0	0	0
Fair Value, Inputs, Level 3 [Member] \| Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	0	0	0
Fair Value, Inputs, Level 3 [Member] \| Other Long-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	0	0	0
Fair Value, Inputs, Level 3 [Member] \| Fixed maturities available for sale \| Debt Security, Government, Non-US [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	0	0	0
Fair Value, Inputs, Level 3 [Member] \| Fixed maturities available for sale \| Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	0	0	0
Fair Value, Inputs, Level 3 [Member] \| Fixed maturities available for sale \| Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)	0	0	0
Guaranteed Minimum Income Benefit \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)	$ (10)	$ 32	$ 63

Fair Value Measurements (Financial Instruments Measured At Fair Value On Recurring Basis) (Detail) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

$ 90,699

$ 85,488

4,027

812

4,345

4,291

7,945

6,062

US Treasury and Government [Member]

1,844

994

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

2,670

3,283

Foreign

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

26,354

23,707

Corporate securities

Mortgage-backed securities

36,331

31,791

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

States, municipalities, and political subdivisions

18,470

19,192

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Estimate of Fair Value Measurement [Member]

6,874

7,515

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Investment Funds Limited Partnerships Partially Owned Investment Companies Fair Value [Member]

7,945

6,062

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

6,770

4,921

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

60

95

Policy Loans [Member]

Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member]

233

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

90,699

85,488

812

4,027

4,345

4,291

882

799

1,844

994

35

24

2

4,388

3,573

106,220

^[1]

95,983

^[2]

52

93

1,158

1,003

Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | US Treasury and Government [Member]

17

13

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Foreign

2,670

3,283

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Corporate securities

26,354

23,707

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Mortgage-backed securities

36,331

31,791

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | States, municipalities, and political subdivisions

18,470

19,192

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 1

6,874

7,515

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

2,148

2,664

728

3,954

2,866

2,803

434

412

0

35

24

2

4,264

3,437

13,701

^[1]

10,070

^[2]

52

93

69

106

Fair Value, Recurring [Member] | Level 1 | US Treasury and Government [Member]

17

13

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 1 | Foreign

2,148

2,664

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 1 | Corporate securities

0

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 1 | Mortgage-backed securities

0

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 1 | States, municipalities, and political subdivisions

0

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 2

0

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

86,372

80,864

15

0

1,474

1,482

438

377

1,844

994

0

0

124

136

90,252

^[1]

83,868

^[2]

0

Fair Value, Recurring [Member] | Level 2 | US Treasury and Government [Member]

0

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 2 | Foreign

522

619

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 2 | Corporate securities

25,808

23,258

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 2 | Mortgage-backed securities

34,758

30,340

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 2 | States, municipalities, and political subdivisions

18,410

19,132

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 3

6,874

7,515

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

2,179

1,960

69

73

5

6

10

0

0

0

0

2,267

^[1]

2,045

^[2]

0

1,089

897

Fair Value, Recurring [Member] | Level 3 | US Treasury and Government [Member]

0

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 3 | Foreign

0

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 3 | Corporate securities

546

449

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 3 | Mortgage-backed securities

1,573

1,451

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Recurring [Member] | Level 3 | States, municipalities, and political subdivisions

60

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Guaranteed Minimum Income Benefit | Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member]

0

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross

1,089

897

Guaranteed Minimum Income Benefit | Fair Value, Recurring [Member] | Level 1

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross

0

Guaranteed Minimum Income Benefit | Fair Value, Recurring [Member] | Level 2

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross

0

Guaranteed Minimum Income Benefit | Fair Value, Recurring [Member] | Level 3

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross

$ 1,089

$ 897

[1]	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $6,770 million, policy loans of $233 million and other investments of $60 million at December 31, 2020 measured using NAV as a practical expedient
[2]	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,921 million and other investments of $95 million at December 31, 2019 measured using NAV as a practical expedient.(2)Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

Fair Value Measurements (Schedule Of Significant Unobservable Inputs Used In Level 3 Liability Valuations) (Detail) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Minimum

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Long-Duration Contracts, Assumptions by Product and Guarantee, Lapse Rate

3.00%

Annuitization rate

0.00%

Maximum

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Long-Duration Contracts, Assumptions by Product and Guarantee, Lapse Rate

34.00%

Annuitization rate

100.00%

Weighted Average

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Long-Duration Contracts, Assumptions by Product and Guarantee, Lapse Rate

4.70%

Annuitization rate

^[1]

3.60%

Level 3 | Other derivative instruments

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value

$ 0

$ 2

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)

0

0

Level 3 | Equity Securities [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)

$ 0

0

0

Level 3 | Short-term investments

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)

(12)

(1)

(13)

0

Level 3 | Other Long-term Investments [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)

0

(1)

(49)

0

Level 3 | Fixed maturities available for sale | Debt Security, Government, Non-US [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)

(57)

(53)

(9)

0

Level 3 | Fixed maturities available for sale | Corporate securities

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)

(423)

(279)

(230)

0

Level 3 | Fixed maturities available for sale | Mortgage-backed securities

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Period Increase (Decrease)

(1)

(3)

(20)

0

Guaranteed Minimum Income Benefit | Level 3

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value

1,089

^[2]

897

861

$ 550

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)

0

(10)

$ 32

$ 63

Guaranteed Minimum Income Benefit | Level 3 | Fair Value, Recurring [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value

$ 1,089

[1]	The weighted average lapse and annuitization rates are determined by weighting each treaty's rates by the GLB contracts fair value.
[2]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

Fair value measurements Fair Value Measurements (Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation) (Details) - Level 3 - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of year, assets	$ 69	$ 57	$ 44
Transfers into Level 3, assets	0	0	0
Transfers out of Level 3, assets	(3)	0	0
Change in Net Unrealized Gains (Losses) included in OCI, Assets	0	1	(2)
Net Realized Gains/Losses, Assets	1	(2)	6
Purchased, assets	23	34	37
Sales, assets	(17)	(21)	(28)
Settlements, assets	0	0	0
Balance- End of year, assets	73	69	57
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	4	(3)	(1)
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets	0	0
Short-term investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of year, assets	6	1	0
Transfers into Level 3, assets	0	0	5
Transfers out of Level 3, assets	0	0	0
Change in Net Unrealized Gains (Losses) included in OCI, Assets	0	0	0
Net Realized Gains/Losses, Assets	1	0	0
Purchased, assets	14	6	9
Sales, assets	(2)	0	0
Settlements, assets	(12)	(1)	(13)
Balance- End of year, assets	5	6	1
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	0	0	0
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets	0	0
Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of year, assets	10	11	263
Transfers into Level 3, assets	0	0	0
Transfers out of Level 3, assets	0	0	(252)
Change in Net Unrealized Gains (Losses) included in OCI, Assets	0	0	(2)
Net Realized Gains/Losses, Assets	0	0	1
Purchased, assets	0	0	50
Sales, assets	0	0	0
Settlements, assets	0	(1)	(49)
Balance- End of year, assets	10	10	11
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	0	0	1
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets	0	0
Available-for-sale Securities [Member] \| Foreign
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of year, assets	449	345	93
Transfers into Level 3, assets	0	11	13
Transfers out of Level 3, assets	(16)	(24)	(2)
Change in Net Unrealized Gains (Losses) included in OCI, Assets	19	13	(12)
Net Realized Gains/Losses, Assets	(1)	(1)	(3)
Purchased, assets	274	228	334
Sales, assets	(122)	(70)	(69)
Settlements, assets	(57)	(53)	(9)
Balance- End of year, assets	546	449	345
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	0	0	(1)
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets	16	7
Available-for-sale Securities [Member] \| Corporate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of year, assets	1,451	1,299	1,037
Transfers into Level 3, assets	134	23	24
Transfers out of Level 3, assets	(73)	(38)	(31)
Change in Net Unrealized Gains (Losses) included in OCI, Assets	(8)	(2)	(4)
Net Realized Gains/Losses, Assets	(30)	(4)	(5)
Purchased, assets	708	577	672
Sales, assets	(186)	(125)	(164)
Settlements, assets	(423)	(279)	(230)
Balance- End of year, assets	1,573	1,451	1,299
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	(5)	(2)	(7)
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets	(6)	(8)
Available-for-sale Securities [Member] \| Mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of year, assets	60	61	78
Transfers into Level 3, assets	0	0	1
Transfers out of Level 3, assets	(1)	(16)	(3)
Change in Net Unrealized Gains (Losses) included in OCI, Assets	0	0	0
Net Realized Gains/Losses, Assets	0	0	0
Purchased, assets	2	19	5
Sales, assets	0	(1)	0
Settlements, assets	(1)	(3)	(20)
Balance- End of year, assets	60	60	61
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	0	0	$ 0
Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets	$ 0	$ 0

Fair value measurements Fair Value Measurements (Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation) (Details) - Level 3 - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Guaranteed Minimum Income Benefit

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Balance - Beginning of year, liabilities

$ 897

$ 861

$ 550

Transfers Into Level 3, liabilities

0

Transfers out of Level 3, liabilities

0

Change in Net Unrealized Gains (Losses) included in OCI, Liabilities

0

Net Realized Gains/Losses, Liabilities

202

4

248

Purchased, liabilities

0

Sales, liabilities

0

Balance - End of year, liabilities

0

1,089

^[1]

897

861

Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Liabilities

202

4

248

Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI

$ 0

0

Other derivative instruments

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Balance - Beginning of year, liabilities

$ 0

2

Transfers Into Level 3, liabilities

0

Transfers out of Level 3, liabilities

0

Change in Net Unrealized Gains (Losses) included in OCI, Liabilities

0

Net Realized Gains/Losses, Liabilities

(2)

Purchased, liabilities

0

Sales, liabilities

0

Balance - End of year, liabilities

0

0

Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Liabilities

$ 0

[1]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

Fair Value Measurements (Carrying Values And Fair Values Of Financial Instruments Not Measured At Fair Value) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	$ 12,510	$ 13,005
Debt Securities, Held-to-maturity	11,697	12,581
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	1,405	1,416
Short-term debt	0	1,299
Long-term debt	14,948	13,559
Trust preferred securities	308	308
Total liabilities	131,333	121,612
US Treasury and Government [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	1,452	1,347
Debt Securities, Held-to-maturity	1,392	1,318
Foreign
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	1,405	1,485
Debt Securities, Held-to-maturity	1,295	1,423
Corporate securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	2,438	2,468
Debt Securities, Held-to-maturity	2,185	2,349
Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	2,146	2,396
Debt Securities, Held-to-maturity	2,000	2,331
States, municipalities, and political subdivisions
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	5,069	5,309
Debt Securities, Held-to-maturity	4,825	5,160
Estimate of Fair Value Measurement [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	1,405	1,416
Short-term debt, Fair Value	0	1,307
Long-term debt, Fair Value	17,487	15,048
Trust preferred securities	473	467
Total liabilities	19,365	18,238
Reported Value Measurement
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	11,653	12,581
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	1,405	1,416
Short-term debt	0	1,299
Long-term debt	14,948	13,559
Trust preferred securities	308	308
Total liabilities	16,661	16,582
Reported Value Measurement \| US Treasury and Government [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	1,392	1,318
Reported Value Measurement \| Foreign
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	1,288	1,423
Reported Value Measurement \| Corporate securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	2,150	2,349
Reported Value Measurement \| Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	1,999	2,331
Reported Value Measurement \| States, municipalities, and political subdivisions
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	4,824	5,160
Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	1,395	1,292
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	0	0
Short-term debt, Fair Value	0	0
Long-term debt, Fair Value	0	0
Trust preferred securities	0	0
Total liabilities	0	0
Level 1 \| US Treasury and Government [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	1,395	1,292
Level 1 \| Foreign
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	0	0
Level 1 \| Corporate securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	0	0
Level 1 \| Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	0	0
Level 1 \| States, municipalities, and political subdivisions
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	0	0
Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	11,115	11,681
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	1,405	1,416
Short-term debt, Fair Value	0	1,307
Long-term debt, Fair Value	17,487	15,048
Trust preferred securities	473	467
Total liabilities	19,365	18,238
Level 2 \| US Treasury and Government [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	57	55
Level 2 \| Foreign
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	1,405	1,485
Level 2 \| Corporate securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	2,438	2,436
Level 2 \| Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	2,146	2,396
Level 2 \| States, municipalities, and political subdivisions
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	5,069	5,309
Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	0	32
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	0	0
Short-term debt, Fair Value	0	0
Long-term debt, Fair Value	0	0
Trust preferred securities	0	0
Total liabilities	0	0
Level 3 \| US Treasury and Government [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	0	0
Level 3 \| Foreign
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	0	0
Level 3 \| Corporate securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	0	32
Level 3 \| Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	0	0
Level 3 \| States, municipalities, and political subdivisions
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity, Fair Value	$ 0	$ 0

Reinsurance (Consolidated Reinsurance) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Premiums written [Abstract]
Direct	$ 37,749	$ 36,848	$ 34,782
Assumed	3,512	3,276	3,186
Ceded	(7,441)	(7,849)	(7,389)
Net	33,820	32,275	30,579
Premiums earned [Abstract]
Direct	37,037	35,876	34,108
Assumed	3,323	3,107	3,175
Ceded	(7,243)	(7,693)	(7,219)
Net premiums earned	33,117	31,290	30,064
Reinsurance recoveries on losses and loss expenses incurred	$ 5,000	$ 4,900	$ 5,600

Reinsurance (Reinsurance Recoverable on Ceded Reinsurance) (Details) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Reinsurance Disclosures [Abstract]

Reinsurance recoverable on unpaid losses

^[1]

$ 14,647

$ 14,181

$ 14,689

$ 14,014

Reinsurance Recoverables on Unpaid Losses, Allowance

257

240

Reinsurance recoverable on paid losses and loss expenses

945

1,000

Reinsurance Recoverables on Paid Losses, Allowance

57

76

Net reinsurance recoverable on losses and loss expenses

^[2]

15,592

15,181

Reinsurance Recoverable, Allowance for Credit Loss

314

316

Reinsurance Recoverables on Future Policy Benefits, Allowance

206

197

$ 5

$ 4

[1]	Net of valuation allowance for uncollectible reinsurance.
[2]	Net of valuation allowance for uncollectible reinsurance.

Reinsurance, Allowance (Details) - USD ($) $ in Millions	12 Months Ended
Reinsurance, Allowance (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Reinsurance Disclosures [Abstract]
Reinsurance Recoverable, Allowance for Credit Loss	$ 314	$ 316
Reinsurance Recoverable, Credit Loss Expense (Reversal)	21
Reinsurance, Loss on Uncollectible Accounts in Period, Amount	(25)
Reinsurance Recoverable, Allowance for Credit Loss, Other	$ 2

Reinsurance (Reinsurance Recoverable by Category and Listing of Largest Reinsurers) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Ceded Credit Risk [Line Items]
Gross reinsurance recoverable	$ 15,906
Provision	$ 314	$ 316
% of Gross	2.00%
Largest reinsurers
Ceded Credit Risk [Line Items]
Gross reinsurance recoverable	$ 7,267
Provision	$ 88
% of Gross	1.20%
Other reinsurers balances rated A- or better
Ceded Credit Risk [Line Items]
Gross reinsurance recoverable	$ 4,901
Provision	$ 58
% of Gross	1.20%
Other reinsurers balances with ratings lower than A- or not rated
Ceded Credit Risk [Line Items]
Gross reinsurance recoverable	$ 466
Provision	$ 64
% of Gross	13.70%
Other pools and government agencies
Ceded Credit Risk [Line Items]
Gross reinsurance recoverable	$ 366
Provision	$ 14
% of Gross	3.80%
Structured settlements
Ceded Credit Risk [Line Items]
Gross reinsurance recoverable	$ 521
Provision	$ 11
% of Gross	2.10%
Other captives
Ceded Credit Risk [Line Items]
Gross reinsurance recoverable	$ 2,107
Provision	$ 11
% of Gross	0.50%
Other
Ceded Credit Risk [Line Items]
Gross reinsurance recoverable	$ 278
Provision	$ 68
% of Gross	24.50%

Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Other intangible assets	$ 5,811	$ 6,063
Intangible assets subject to amortization	2,846	3,114
Intangible assets not subject to amortization	2,965	2,949
Amortization of Purchased Intangibles	$ 290	$ 305	$ 339

Intangible Assets (Roll-forward of Goodwill by Business Segment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Balance at beginning of period	$ 15,296	$ 15,271
Foreign exchange revaluation and other	60	25
Balance at end of period	15,400	15,296
North America Commercial P&C Insurance
Goodwill [Roll Forward]
Balance at beginning of period	6,955	6,946
Foreign exchange revaluation and other	17	9
Balance at end of period	6,972	6,955
Segment Insurance North American Personal P&C [Member] [Member]
Goodwill [Roll Forward]
Balance at beginning of period	2,234	2,230
Foreign exchange revaluation and other	6	4
Balance at end of period	2,240	2,234
North America Agricultural Insurance
Goodwill [Roll Forward]
Balance at beginning of period	134	134
Foreign exchange revaluation and other	0	0
Balance at end of period	134	134
Overseas General Insurance
Goodwill [Roll Forward]
Balance at beginning of period	4,785	4,770
Foreign exchange revaluation and other	35	15
Balance at end of period	4,836	4,785
Segment Global Reinsurance [Member]
Goodwill [Roll Forward]
Balance at beginning of period	371	371
Foreign exchange revaluation and other	0	0
Balance at end of period	371	371
Life Insurance
Goodwill [Roll Forward]
Balance at beginning of period	817	820
Foreign exchange revaluation and other	2	(3)
Balance at end of period	847	$ 817
Banchile Seguros de Vida [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	44
Banchile Seguros de Vida [Member] \| North America Commercial P&C Insurance
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0
Banchile Seguros de Vida [Member] \| Segment Insurance North American Personal P&C [Member] [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0
Banchile Seguros de Vida [Member] \| North America Agricultural Insurance
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0
Banchile Seguros de Vida [Member] \| Overseas General Insurance
Goodwill [Roll Forward]
Goodwill, Acquired During Period	16
Banchile Seguros de Vida [Member] \| Segment Global Reinsurance [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period	0
Banchile Seguros de Vida [Member] \| Life Insurance
Goodwill [Roll Forward]
Goodwill, Acquired During Period	$ 28

Intangible Assets (Estimated Amortization Expense Over Next Five Years) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
2021, Other intangible assets	$ 286
2022, Other intangible assets	284
2023, Other intangible assets	267
2024, Other intangible assets	244
2025, Other intangible assets	228
Total, Other intangible assets	1,309
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
2021, Other intangible assets	89
2022, Other intangible assets	101
2023, Other intangible assets	96
2024, Other intangible assets	90
2025, Other intangible assets	89
Total, Other intangible assets	465
The Chubb Corporation [Member]
Finite-Lived Intangible Assets [Line Items]
2021, Other intangible assets	197
2022, Other intangible assets	183
2023, Other intangible assets	171
2024, Other intangible assets	154
2025, Other intangible assets	139
Total, Other intangible assets	844
The Chubb Corporation [Member] \| Agency distribution relationships and renewal rights [Member]
Finite-Lived Intangible Assets [Line Items]
2021, Other intangible assets	217
2022, Other intangible assets	197
2023, Other intangible assets	178
2024, Other intangible assets	160
2025, Other intangible assets	145
Total, Other intangible assets	897
The Chubb Corporation [Member] \| Fair Value Adjustment to Acquired Loss Reserves [Member]
Finite-Lived Intangible Assets [Line Items]
2021, Other intangible assets	(20)
2022, Other intangible assets	(14)
2023, Other intangible assets	(7)
2024, Other intangible assets	(6)
2025, Other intangible assets	(6)
Total, Other intangible assets	(53)
Balance of FV adjustment on Unpaid Losses and Loss Expenses	$ 110	$ 145
Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	25 years

Intangible Assets (VOBA) (Details) - USD ($) $ in Millions	12 Months Ended
Intangible Assets (VOBA) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
VOBA Roll Forward
VOBA balance, beginning of year	$ 306	$ 295	$ 326
Amortization of Value of Business Acquired (VOBA)	(27)	(24)	(25)
VOBA Foreign exchange revaluation	(16)	35	(6)
VOBA balance, end of year	263	$ 306	$ 295
Present Value of Future Insurance Profits, Amortization Expense, Next Five Years [Abstract]
2021, VOBA	22
2022, VOBA	21
2023, VOBA	19
2024, VOBA	17
2025, VOBA	16
Total, VOBA	$ 95

Unpaid losses and loss expenses (Unpaid Losses and Loss Expenses Rollforward) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Unpaid Losses and Loss Expenses [Roll Forward]

Gross unpaid losses and loss expenses, beginning of year

$ 62,690

$ 62,960

$ 63,179

Reinsurance recoverable on unpaid losses, beginning of year

^[1]

(14,181)

(14,689)

(14,014)

Net unpaid losses and loss expenses, beginning of year

48,509

48,271

49,165

Net losses and loss expenses incurred in respect of losses incurring in Current Year

22,124

19,575

19,048

Net losses and loss expenses paid in Current Year

^[2]

(414)

(845)

(981)

Total

21,710

18,730

18,067

7,782

7,894

7,544

Net losses and loss expenses paid in Prior Year

9,652

10,579

10,796

Total

17,434

18,473

18,340

Foreign currency revaluation and other

379

(19)

(621)

Net unpaid losses and loss expenses, end of year

53,164

48,509

48,271

Reinsurance recoverable on unpaid losses, end of year

^[1]

14,647

14,181

14,689

Gross unpaid losses and loss expenses, end of year

67,811

62,690

62,960

Prior Period Development, net adjustments

$ 19

$ 53

$ 85

[1]	Net of valuation allowance for uncollectible reinsurance.
[2]	Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments and earned premiums totaling $19 million, $53 million, and $85 million for 2020, 2019, and 2018, respectively.

Unpaid losses and loss expenses Unpaid losses and loss expenses (Reconciliation of reserve Balances to Liability for Unpaid Loss)(Details) (Details) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

$ 50,492

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

14,687

Short-duration Insurance Contracts, Liability for Unpaid Claims and Claim Adjustment Expense, Aggregate Reconciling Items

^[1]

1,109

Unpaid unallocated loss adjustment expenses

1,523

North America Commercial P&C Insurance - Workers' Compensation [Member]

67,811

$ 62,690

$ 62,960

$ 63,179

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

9,600

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

1,461

North America Commercial P&C Insurance - Liability [Member]

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

17,441

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

5,743

North America Commercial P&C Insurance - Other Casualty [Member]

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

2,124

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

564

North America Commercial P&C Insurance - Non-Casualty [Member]

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

2,491

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

1,380

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

3,025

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

141

Overseas General Insurance - Casualty [Member]

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

6,832

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

2,426

Overseas General Insurance - Non-Casualty [Member]

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

2,725

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

1,686

Global Reinsurance - Casualty [Member]

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

1,200

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

29

Global Reinsurance - Non-Casualty [Member]

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

312

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

104

Other Segments [Member]

Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]

Unpaid Loss and Allocated Loss Adjustment Expenses, Net

4,742

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

$ 1,153

[1]	Primarily includes the claims reserve of our International A&H business and Life Insurance segment reserves.

Unpaid losses and loss expenses Unpaid Losses and loss expenses, claims development (Cumulative Net incurred Loss and Allocated Loss Adjustment Expense) (Details) $ in Millions	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	$ 50,492
North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	11,959
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	5,107
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	9,600
North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	35,276
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	19,294
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	17,441
North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	5,415
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	3,578
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	2,124
North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	19,870
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	17,383
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	2,491
North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	25,502
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	22,501
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	3,025
Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	13,470
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	7,124
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	6,832
Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	20,129
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	17,498
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	2,725
Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	2,930
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	2,061
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	1,200
Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	2,233
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	1,931
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	312
Short-duration Insurance Contracts, Accident Year 2010 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	973	$ 988	$ 1,009	$ 1,012	$ 1,022	$ 1,053	$ 1,049	$ 1,046	$ 1,030	$ 1,037
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	208
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 654	640	616	595	567	533	484	411	294	119
Cumulative Number of Reported Claims	45,000
Short-duration Insurance Contracts, Accident Year 2010 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,143	3,193	3,316	3,384	3,498	3,593	3,665	3,630	3,586	3,500
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	226
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,863	2,827	2,741	2,659	2,477	2,214	1,805	1,209	652	160
Cumulative Number of Reported Claims	25,000
Short-duration Insurance Contracts, Accident Year 2010 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 503	513	511	517	525	533	549	581	590	581
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	13
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 486	486	480	466	461	437	400	341	235	86
Cumulative Number of Reported Claims	16,000
Short-duration Insurance Contracts, Accident Year 2010 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,833	1,835	1,835	1,835	1,840	1,835	1,856	1,877	1,934	1,960
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	4
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,830	1,825	1,821	1,816	1,811	1,787	1,777	1,718	1,574	939
Cumulative Number of Reported Claims	416,000
Short-duration Insurance Contracts, Accident Year 2010 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,157	2,159	2,158	2,160	2,161	2,164	2,173	2,185	2,210	2,208
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	7
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,149	2,148	2,146	2,139	2,129	2,105	2,052	1,972	1,835	1,360
Cumulative Number of Reported Claims	179,000
Short-duration Insurance Contracts, Accident Year 2010 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,025	1,023	1,027	1,079	1,090	1,158	1,244	1,254	1,262	1,255
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	31
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 901	876	842	789	713	631	528	393	243	86
Cumulative Number of Reported Claims	37,000
Short-duration Insurance Contracts, Accident Year 2010 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,843	1,844	1,849	1,859	1,867	1,879	1,898	1,938	1,995	1,908
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	6
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,806	1,807	1,808	1,804	1,795	1,780	1,750	1,694	1,486	765
Cumulative Number of Reported Claims	543,000
Short-duration Insurance Contracts, Accident Year 2010 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 389	402	409	415	418	428	433	430	415	408
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	15
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	338	332	325	312	292	267	236	195	146	70
Short-duration Insurance Contracts, Accident Year 2010 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	269	267	268	267	268	267	266	276	279	277
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	265	264	263	262	259	254	236	210	179	$ 87
Short-duration Insurance Contracts, Accident Year 2011 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	953	977	986	989	1,011	1,040	1,030	1,011	1,050
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	234
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 612	592	574	532	486	436	365	271	111
Cumulative Number of Reported Claims	44,000
Short-duration Insurance Contracts, Accident Year 2011 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,235	3,235	3,331	3,426	3,524	3,565	3,613	3,628	3,552
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	353
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,688	2,619	2,502	2,326	2,092	1,680	1,172	656	166
Cumulative Number of Reported Claims	25,000
Short-duration Insurance Contracts, Accident Year 2011 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 505	507	509	519	520	561	577	606	634
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	2
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 502	493	487	470	435	387	320	223	69
Cumulative Number of Reported Claims	16,000
Short-duration Insurance Contracts, Accident Year 2011 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,844	1,850	1,844	1,847	1,859	1,864	1,883	1,916	2,033
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	(8)
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,844	1,842	1,816	1,822	1,795	1,767	1,698	1,577	715
Cumulative Number of Reported Claims	426,000
Short-duration Insurance Contracts, Accident Year 2011 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,190	2,194	2,189	2,186	2,186	2,191	2,183	2,183	2,185
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	18
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,165	2,163	2,164	2,149	2,117	2,063	1,957	1,806	1,177
Cumulative Number of Reported Claims	188,000
Short-duration Insurance Contracts, Accident Year 2011 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,272	1,304	1,315	1,337	1,343	1,346	1,326	1,261	1,290
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	87
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,040	973	929	857	713	597	441	252	75
Cumulative Number of Reported Claims	38,000
Short-duration Insurance Contracts, Accident Year 2011 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,562	1,570	1,575	1,590	1,599	1,605	1,661	1,702	1,712
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	13
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,532	1,532	1,530	1,518	1,508	1,485	1,425	1,237	679
Cumulative Number of Reported Claims	555,000
Short-duration Insurance Contracts, Accident Year 2011 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 379	374	372	373	379	395	392	384	387
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	11
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	342	336	324	309	293	262	223	168	78
Short-duration Insurance Contracts, Accident Year 2011 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	184	186	186	188	191	192	202	211	233
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	180	181	180	178	173	167	157	130	$ 45
Short-duration Insurance Contracts, Accident Year 2012 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,014	1,037	1,073	1,086	1,127	1,122	1,108	1,109
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	280
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 633	616	587	553	506	422	286	107
Cumulative Number of Reported Claims	43,000
Short-duration Insurance Contracts, Accident Year 2012 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,964	3,122	3,216	3,430	3,533	3,543	3,542	3,547
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	317
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,465	2,374	2,232	2,007	1,597	1,192	548	130
Cumulative Number of Reported Claims	25,000
Short-duration Insurance Contracts, Accident Year 2012 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 458	462	462	469	516	523	531	527
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	21
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 426	419	411	385	348	271	197	69
Cumulative Number of Reported Claims	18,000
Short-duration Insurance Contracts, Accident Year 2012 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,344	1,338	1,340	1,340	1,360	1,337	1,424	1,434
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	7
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,335	1,333	1,324	1,311	1,285	1,238	1,138	651
Cumulative Number of Reported Claims	455,000
Short-duration Insurance Contracts, Accident Year 2012 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,948	1,945	1,937	1,924	1,900	1,897	1,888	1,860
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	26
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,917	1,895	1,885	1,843	1,787	1,688	1,504	1,043
Cumulative Number of Reported Claims	132,000
Short-duration Insurance Contracts, Accident Year 2012 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,148	1,182	1,242	1,276	1,322	1,276	1,279	1,281
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	86
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 952	899	829	725	579	428	267	85
Cumulative Number of Reported Claims	39,000
Short-duration Insurance Contracts, Accident Year 2012 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,610	1,620	1,633	1,660	1,665	1,714	1,780	1,787
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	19
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,578	1,575	1,567	1,549	1,512	1,480	1,284	696
Cumulative Number of Reported Claims	573,000
Short-duration Insurance Contracts, Accident Year 2012 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 311	317	324	332	331	330	327	321
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	13
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	272	269	260	242	222	186	143	65
Short-duration Insurance Contracts, Accident Year 2012 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	140	141	141	144	143	148	160	162
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	0
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	139	137	137	134	131	121	103	$ 46
Short-duration Insurance Contracts, Accident Year 2013 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,073	1,100	1,163	1,215	1,217	1,201	1,207
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	347
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 599	566	532	484	410	295	113
Cumulative Number of Reported Claims	45,000
Short-duration Insurance Contracts, Accident Year 2013 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,346	3,470	3,656	3,717	3,674	3,586	3,535
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	572
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,584	2,442	2,202	1,804	1,250	679	164
Cumulative Number of Reported Claims	25,000
Short-duration Insurance Contracts, Accident Year 2013 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 539	539	555	597	581	583	595
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	25
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 501	474	455	391	318	220	80
Cumulative Number of Reported Claims	17,000
Short-duration Insurance Contracts, Accident Year 2013 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,558	1,550	1,549	1,559	1,579	1,661	1,643
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	10
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,554	1,546	1,532	1,506	1,484	1,374	820
Cumulative Number of Reported Claims	483,000
Short-duration Insurance Contracts, Accident Year 2013 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,141	2,147	2,160	2,146	2,192	2,206	2,205
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	14
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,116	2,106	2,080	2,035	1,926	1,765	1,310
Cumulative Number of Reported Claims	144,000
Short-duration Insurance Contracts, Accident Year 2013 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,165	1,206	1,293	1,378	1,362	1,352	1,279
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	151
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 876	811	725	608	473	293	111
Cumulative Number of Reported Claims	39,000
Short-duration Insurance Contracts, Accident Year 2013 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,810	1,817	1,828	1,864	1,875	1,932	1,863
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	7
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,774	1,759	1,746	1,715	1,651	1,438	758
Cumulative Number of Reported Claims	548,000
Short-duration Insurance Contracts, Accident Year 2013 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 331	348	345	343	340	335	334
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	16
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	287	277	265	249	218	185	92
Short-duration Insurance Contracts, Accident Year 2013 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	182	183	184	186	183	182	167
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	3
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	175	173	171	165	154	131	$ 66
Short-duration Insurance Contracts, Accident Year 2014 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,154	1,217	1,279	1,276	1,259	1,282
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	419
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 606	564	501	418	301	116
Cumulative Number of Reported Claims	50,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,736	3,943	3,976	3,819	3,709	3,560
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	855
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,533	2,291	1,856	1,206	605	138
Cumulative Number of Reported Claims	27,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 455	458	515	502	470	487
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	35
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 395	371	305	215	137	47
Cumulative Number of Reported Claims	15,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,589	1,605	1,638	1,650	1,745	1,736
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	(1)
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,574	1,572	1,556	1,488	1,343	727
Cumulative Number of Reported Claims	545,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,570	2,563	2,544	2,561	2,550	2,494
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	21
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,508	2,478	2,392	2,271	2,084	1,499
Cumulative Number of Reported Claims	148,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,265	1,326	1,351	1,328	1,296	1,196
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	199
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 884	802	679	497	287	86
Cumulative Number of Reported Claims	41,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,003	2,011	2,030	2,062	2,083	1,963
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	24
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,927	1,897	1,875	1,793	1,560	857
Cumulative Number of Reported Claims	571,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 306	309	301	300	290	285
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	22
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	250	233	217	192	159	90
Short-duration Insurance Contracts, Accident Year 2014 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	161	155	162	162	155	147
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	4
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	153	147	143	133	104	$ 56
Short-duration Insurance Contracts, Accident Year 2015 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,269	1,378	1,383	1,361	1,367
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	530
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 584	529	452	326	122
Cumulative Number of Reported Claims	51,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,799	3,805	3,692	3,595	3,534
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	962
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,334	1,975	1,336	663	171
Cumulative Number of Reported Claims	27,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 481	524	527	502	504
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	61
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 374	323	246	146	52
Cumulative Number of Reported Claims	16,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,818	1,782	1,799	1,890	1,911
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	32
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,761	1,733	1,656	1,504	846
Cumulative Number of Reported Claims	650,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,471	2,482	2,545	2,535	2,440
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	45
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,370	2,314	2,211	2,052	1,453
Cumulative Number of Reported Claims	154,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,425	1,437	1,407	1,337	1,232
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	341
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 815	687	534	324	127
Cumulative Number of Reported Claims	43,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,040	2,036	2,058	2,071	2,070
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	22
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,981	1,954	1,881	1,679	1,013
Cumulative Number of Reported Claims	581,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 245	236	236	228	224
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	27
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	175	159	143	113	58
Short-duration Insurance Contracts, Accident Year 2015 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	190	194	192	189	184
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	5
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	178	172	161	133	$ 57
Short-duration Insurance Contracts, Accident Year 2016 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,393	1,399	1,380	1,413
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	723
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 516	437	313	120
Cumulative Number of Reported Claims	50,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,631	3,581	3,499	3,322
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,475
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,701	1,162	617	161
Cumulative Number of Reported Claims	27,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 616	577	566	532
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	118
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 381	313	175	66
Cumulative Number of Reported Claims	17,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,522	2,505	2,608	2,704
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	51
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,394	2,303	2,087	979
Cumulative Number of Reported Claims	763,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,998	3,002	3,069	3,035
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	96
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,799	2,668	2,520	1,698
Cumulative Number of Reported Claims	163,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,433	1,381	1,332	1,227
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	384
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 702	535	323	98
Cumulative Number of Reported Claims	43,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,225	2,245	2,264	2,222
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	18
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,106	2,029	1,848	1,051
Cumulative Number of Reported Claims	589,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 218	221	217	215
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	28
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	140	122	100	47
Short-duration Insurance Contracts, Accident Year 2016 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	451	454	424	397
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	10
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	415	402	322	$ 191
Short-duration Insurance Contracts, Accident Year 2017 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,379	1,361	1,359
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	709
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 451	329	130
Cumulative Number of Reported Claims	51,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,696	3,494	3,375
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,737
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,303	754	190
Cumulative Number of Reported Claims	28,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 575	564	536
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	198
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 270	169	74
Cumulative Number of Reported Claims	17,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,175	2,240	2,053
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	71
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,018	1,825	1,027
Cumulative Number of Reported Claims	901,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,103	3,037	3,010
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	244
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,706	2,549	1,926
Cumulative Number of Reported Claims	169,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,447	1,383	1,330
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	671
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 503	334	112
Cumulative Number of Reported Claims	43,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,237	2,276	2,186
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	48
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,962	1,753	1,006
Cumulative Number of Reported Claims	624,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 256	249	246
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	48
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	126	96	42
Short-duration Insurance Contracts, Accident Year 2017 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	303	300	288
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	(8)
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	277	258	$ 94
Short-duration Insurance Contracts, Accident Year 2018 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,384	1,391
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	767
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 341	143
Cumulative Number of Reported Claims	47,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,628	3,452
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	2,381
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 671	176
Cumulative Number of Reported Claims	28,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 637	606
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	284
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 190	70
Cumulative Number of Reported Claims	16,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,037	2,052
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	166
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,677	1,030
Cumulative Number of Reported Claims	1,036,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,993	2,957
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	329
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,437	1,668
Cumulative Number of Reported Claims	155,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,480	1,409
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	809
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 341	126
Cumulative Number of Reported Claims	40,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,228	2,208
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	94
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,747	1,050
Cumulative Number of Reported Claims	640,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 248	239
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	90
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	90	40
Short-duration Insurance Contracts, Accident Year 2018 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	141	143
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	29
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	86	$ 35
Short-Duration Insurance Contract, Accident Year 2019 [Member] \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,367
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,086
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 111
Cumulative Number of Reported Claims	24,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 4,098
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	3,695
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 152
Cumulative Number of Reported Claims	24,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 646
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	517
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 53
Cumulative Number of Reported Claims	9,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,150
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,061
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,396
Cumulative Number of Reported Claims	927,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,931
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,119
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,334
Cumulative Number of Reported Claims	100,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,810
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,493
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 110
Cumulative Number of Reported Claims	28,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,571
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	804
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,085
Cumulative Number of Reported Claims	518,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 247
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	153
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	41
Short-Duration Insurance Contract, Accident Year 2019 [Member] \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	212
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	110
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	63
prior to 2011 \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	2,748
prior to 2011 \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	1,459
prior to 2011 \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	287
prior to 2011 \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	4
prior to 2011 \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	24
prior to 2011 \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	486
prior to 2011 \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	94
prior to 2011 \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	331
prior to 2011 \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	10
2011 - 2020 \| North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	6,852
2011 - 2020 \| North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	15,982
2011 - 2020 \| North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	1,837
2011 - 2020 \| North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	2,487
2011 - 2020 \| North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	3,001
2011 - 2020 \| Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	6,346
2011 - 2020 \| Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	2,631
2011 - 2020 \| Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	869
2011 - 2020 \| Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	$ 302

Unpaid losses and loss expenses Unpaid losses and loss expenses (Details) (Supplementary PPD) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
North America Commercial P&C Insurance - Workers' Compensation [Member]
Supplementary PPD [Line Items]
Short-Duration PPD	$ (350)
North America Commercial P&C Insurance - Workers' Compensation [Member] \| prior to 2011
Supplementary PPD [Line Items]
Short-Duration PPD	(94)
North America Commercial P&C Insurance - Workers' Compensation [Member] \| 2011 - 2020
Supplementary PPD [Line Items]
Short-Duration PPD	(256)
North America Commercial P&C Insurance - Liability [Member]
Supplementary PPD [Line Items]
Short-Duration PPD	(293)
North America Commercial P&C Insurance - Liability [Member] \| prior to 2011
Supplementary PPD [Line Items]
Short-Duration PPD	(176)
North America Commercial P&C Insurance - Liability [Member] \| 2011 - 2020
Supplementary PPD [Line Items]
Short-Duration PPD	(117)
North America Commercial P&C Insurance - Other Casualty [Member]
Supplementary PPD [Line Items]
Short-Duration PPD	42
North America Commercial P&C Insurance - Other Casualty [Member] \| prior to 2011
Supplementary PPD [Line Items]
Short-Duration PPD	23
North America Commercial P&C Insurance - Other Casualty [Member] \| 2011 - 2020
Supplementary PPD [Line Items]
Short-Duration PPD	19
North America Commercial P&C Insurance - Non-Casualty [Member]
Supplementary PPD [Line Items]
Short-Duration PPD	(35)
North America Commercial P&C Insurance - Non-Casualty [Member] \| prior to 2011
Supplementary PPD [Line Items]
Short-Duration PPD	2
North America Commercial P&C Insurance - Non-Casualty [Member] \| 2011 - 2020
Supplementary PPD [Line Items]
Short-Duration PPD	(37)
North America Personal P&C Insurance [Member]
Supplementary PPD [Line Items]
Short-Duration PPD	84
North America Personal P&C Insurance [Member] \| prior to 2011
Supplementary PPD [Line Items]
Short-Duration PPD	(1)
North America Personal P&C Insurance [Member] \| 2011 - 2020
Supplementary PPD [Line Items]
Short-Duration PPD	85
Overseas General Insurance - Casualty [Member]
Supplementary PPD [Line Items]
Short-Duration PPD	(50)
Overseas General Insurance - Casualty [Member] \| prior to 2011
Supplementary PPD [Line Items]
Short-Duration PPD	(59)
Overseas General Insurance - Casualty [Member] \| 2011 - 2020
Supplementary PPD [Line Items]
Short-Duration PPD	9
Overseas General Insurance - Non-Casualty [Member]
Supplementary PPD [Line Items]
Short-Duration PPD	(77)
Overseas General Insurance - Non-Casualty [Member] \| prior to 2011
Supplementary PPD [Line Items]
Short-Duration PPD	(8)
Overseas General Insurance - Non-Casualty [Member] \| 2011 - 2020
Supplementary PPD [Line Items]
Short-Duration PPD	(69)
Global Reinsurance - Casualty [Member]
Supplementary PPD [Line Items]
Short-Duration PPD	(22)
Global Reinsurance - Casualty [Member] \| prior to 2011
Supplementary PPD [Line Items]
Short-Duration PPD	(10)
Global Reinsurance - Casualty [Member] \| 2011 - 2020
Supplementary PPD [Line Items]
Short-Duration PPD	(12)
Global Reinsurance - Non-Casualty [Member]
Supplementary PPD [Line Items]
Short-Duration PPD	(2)
Global Reinsurance - Non-Casualty [Member] \| prior to 2011
Supplementary PPD [Line Items]
Short-Duration PPD	0
Global Reinsurance - Non-Casualty [Member] \| 2011 - 2020
Supplementary PPD [Line Items]
Short-Duration PPD	$ (2)

Unpaid losses and loss expenses Unpaid losses and loss expenses (Average Annual Payout) (Details)	Dec. 31, 2020
North America Commercial P&C Insurance - Workers' Compensation [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	10.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	16.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	10.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	7.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	5.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	4.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	3.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	2.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	2.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	1.00%
North America Commercial P&C Insurance - Liability [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	5.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	14.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	17.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	16.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	12.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	7.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	5.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	3.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	2.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	1.00%
North America Commercial P&C Insurance - Other Casualty [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	12.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	23.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	19.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	14.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	10.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	5.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	3.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	2.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.00%
North America Commercial P&C Insurance - Non-Casualty [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	46.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	38.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	8.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	3.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.00%
North America Personal P&C Insurance [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	57.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	24.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	7.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	5.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	3.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.00%
Overseas General Insurance - Casualty [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	8.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	15.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	15.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	12.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	10.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	8.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	6.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	4.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	4.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	3.00%
Overseas General Insurance - Non-Casualty [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	45.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	35.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	11.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	3.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	2.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.00%
Global Reinsurance - Casualty [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	21.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	23.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	12.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	10.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	7.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	5.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	4.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	3.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	2.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	2.00%
Global Reinsurance - Non-Casualty [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	33.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	38.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	14.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	6.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	4.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	2.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.00%

Unpaid losses and loss expenses Unpaid losses and loss expenses (Details) (Supplementary PPD Reconciliation) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

^[1]

$ (414)

$ (845)

$ (981)

19

53

85

Alternative Risk Solutions [Member]

(395)

(792)

(896)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Workers' Compensation [Member]

80

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

15

Long Tail [Member]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(313)

(642)

(486)

Short Tail [Member]

Segments included in loss triangles [Domain]

(82)

(150)

(410)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(828)

^[2]

(125)

10

Segments included in loss triangles [Domain] | 2011 - 2019

(818)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Segments included in loss triangles [Domain] | prior to 2011

(380)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(323)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(733)

^[2],[3]

(97)

31

North America Commercial P&C Insurance | 2011 - 2019

(702)

(649)

(610)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | prior to 2011

(391)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Long Tail [Member]

(245)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(703)

^[2]

(102)

31

North America Commercial P&C Insurance | Long Tail [Member] | North America Workers' Compensation [Member]

(672)

(668)

(395)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Long Tail [Member] | 2011 - 2019

(303)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Long Tail [Member] | prior to 2011

(354)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short Tail [Member]

(247)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(30)

^[2]

5

0

North America Commercial P&C Insurance | Short Tail [Member] | 2011 - 2019

(30)

19

(215)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short Tail [Member] | prior to 2011

(37)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

2

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Personal P&C Insurance [Member] | Long Tail [Member]

63

(95)

41

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Personal P&C Insurance [Member] | Short Tail [Member]

0

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

81

^[2]

(3)

(18)

North America Personal P&C Insurance [Member] | Short Tail [Member] | 2011 - 2019

63

(95)

41

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Personal P&C Insurance [Member] | Short Tail [Member] | prior to 2011

85

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(1)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(150)

^[2],[4]

(23)

0

Overseas General Insurance | International A&H [Member]

(150)

(92)

(212)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | 2011 - 2019

22

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | prior to 2011

(60)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Long Tail [Member]

(67)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(49)

^[2]

1

0

Overseas General Insurance | Long Tail [Member] | 2011 - 2019

(49)

(68)

(67)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Long Tail [Member] | prior to 2011

9

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Short Tail [Member]

(59)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(101)

^[2]

(24)

0

Overseas General Insurance | Short Tail [Member] | 2011 - 2019

(101)

(24)

(145)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Short Tail [Member] | prior to 2011

(69)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(8)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(26)

^[2]

(2)

(3)

Segment Global Reinsurance [Member] | 2011 - 2019

(29)

(50)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Segment Global Reinsurance [Member] | prior to 2011

(14)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Segment Global Reinsurance [Member] | Long Tail [Member]

(10)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(23)

^[2]

(1)

(2)

Segment Global Reinsurance [Member] | Long Tail [Member] | 2011 - 2019

(25)

(59)

(69)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Segment Global Reinsurance [Member] | Long Tail [Member] | prior to 2011

(12)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Segment Global Reinsurance [Member] | Short Tail [Member]

(10)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(3)

^[2]

(1)

(1)

Segment Global Reinsurance [Member] | Short Tail [Member] | 2011 - 2019

(4)

30

19

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Segment Global Reinsurance [Member] | Short Tail [Member] | prior to 2011

(2)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

0

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Agricultural Insurance | Long Tail [Member]

(10)

(80)

(110)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Agricultural Insurance | Short Tail [Member]

0

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(19)

9

Corporate Segment [Member]

(10)

(80)

(110)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Corporate Segment [Member] | Long Tail [Member]

433

153

45

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

433

0

Corporate Segment [Member] | Short Tail [Member]

433

153

45

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

$ 0

[1]	Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments and earned premiums totaling $19 million, $53 million, and $85 million for 2020, 2019, and 2018, respectively.
[2]	Other includes the impact of foreign exchange.
[3]	Includes favorable development of $80 million related to our Alternative Risk Solutions business (U.S. and Bermuda) and an adjustment to exclude $15 million in unfavorable development in the workers' compensation line, associated with an increase in exposure for which additional premiums were collected; the remaining difference relates to a number of other items, none of which are individually material.(3) Includes premium returns associated with our Alternative Risk Solutions business, which is excluded from the triangles.
[4]	Includes favorable development of $22 million related to International A&H business; the remaining difference relates to a number of other items, none of which are individually material.

Unpaid losses and loss expenses Unpaid losses and loss expenses (PPD table) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Prior Period Development Percentage Opening Net Unpaid Reserves

$ (395)

$ (792)

$ (896)

^[1]

0.80%

1.60%

1.80%

Long Tail [Member]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

$ (313)

$ (642)

$ (486)

Short Tail [Member]

(82)

(150)

(410)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Prior Period Development Percentage Opening Net Unpaid Reserves

$ (702)

$ (649)

$ (610)

^[1]

1.40%

1.30%

1.20%

North America Commercial P&C Insurance | Long Tail [Member]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short Tail [Member]

$ (672)

$ (668)

$ (395)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(30)

19

(215)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Prior Period Development Percentage Opening Net Unpaid Reserves

$ 63

$ (95)

$ 41

^[1]

0.10%

0.20%

0.10%

North America Personal P&C Insurance [Member] | Long Tail [Member]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Personal P&C Insurance [Member] | Short Tail [Member]

$ 0

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

63

(95)

41

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Prior Period Development Percentage Opening Net Unpaid Reserves

$ (10)

$ (80)

$ (110)

^[1]

0.00%

0.20%

North America Agricultural Insurance | Long Tail [Member]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

North America Agricultural Insurance | Short Tail [Member]

$ 0

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(10)

(80)

(110)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Prior Period Development Percentage Opening Net Unpaid Reserves

$ (150)

$ (92)

$ (212)

^[1]

0.30%

0.20%

0.40%

Overseas General Insurance | Long Tail [Member]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Short Tail [Member]

$ (49)

$ (68)

$ (67)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

(101)

(24)

(145)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Prior Period Development Percentage Opening Net Unpaid Reserves

$ (29)

$ (50)

^[1]

0.10%

Segment Global Reinsurance [Member] | Long Tail [Member]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Segment Global Reinsurance [Member] | Short Tail [Member]

$ (25)

$ (59)

$ (69)

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Corporate Segment [Member]

(4)

30

19

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Prior Period Development Percentage Opening Net Unpaid Reserves

$ 433

$ 153

$ 45

^[1]

0.90%

0.30%

0.10%

Corporate Segment [Member] | Long Tail [Member]

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Corporate Segment [Member] | Short Tail [Member]

$ 433

$ 153

$ 45

Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]

Liability For Asbestos And Environmental Claims Net Roll Forward

$ 0

[1]	Calculated based on the beginning of period consolidated net unpaid losses and loss expenses.

Unpaid losses and loss expenses (A&E Loss Roll-forward) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Balance (gross) at beginning of year

$ 1,988

$ 2,117

$ 2,228

Balance (gross) at end of year

1,326

1,447

1,527

Incurred activity, gross

229

175

237

Incurred activity, net

^[1]

131

98

(22)

Paid activity, gross

(349)

(304)

(348)

Paid activity, net

(205)

(219)

(58)

1,868

1,988

2,117

Liability For Asbestos And Environmental Claims Net Roll Forward

1,252

1,326

1,447

Asbestos Issue [Member]

Balance (gross) at beginning of year

1,459

1,492

1,621

Balance (gross) at end of year

916

964

1,051

Incurred activity, gross

150

129

136

Incurred activity, net

90

70

75

Paid activity, gross

(258)

(162)

(265)

Paid activity, net

(133)

(118)

(162)

1,351

1,459

1,492

Environmental Issue [Member]

873

916

964

Liability For Asbestos And Environmental Claims Net Roll Forward

Balance (gross) at beginning of year

529

625

607

Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease)

410

483

476

Incurred activity, gross

79

46

101

Incurred activity, net

41

28

(97)

Paid activity, gross

(91)

(142)

(83)

(72)

(101)

104

Balance (gross) at end of year

517

529

625

Liability For Asbestos And Environmental Claims Net Roll Forward

379

410

$ 483

Brandywine [Member]

754

Westchester Specialty [Member]

736

754

Liability For Asbestos And Environmental Claims Net Roll Forward

117

Liability For Asbestos And Environmental Claims Net Roll Forward

103

117

Other Segments [Member]

74

The Chubb Corporation [Member]

80

74

Liability For Asbestos And Environmental Claims Net Roll Forward

381

Liability for Claims and Claims Adjustment Expense [Line Items]

$ 333

$ 381

[1]	Excludes unallocated loss expenses and the net activity reflects third-party reinsurance other than the aggregate excess of loss reinsurance provided by National Indemnity Company (NICO) to Westchester Specialty (see Westchester Specialty section below)

Unpaid losses and loss expenses (Narrative) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2004

$ (395)

$ (792)

$ (896)

Prior Period Development Percentage Opening Net Unpaid Reserves

$ 19

$ 53

$ 85

^[1]

0.80%

1.60%

1.80%

Incurred activity

$ 21,710

$ 18,730

$ 18,067

Liability for Claims and Claims Adjustment Expense

67,811

62,690

62,960

$ 63,179

Brandywine Run-off [Member]

Liability for Claims and Claims Adjustment Expense [Line Items]

Incurred activity

573

Reinsurance coverage to Century provided by ACE INA under XOL

800

Statutory capital and surplus

25

Dividend retention fund established by INA Financial Corporation

50

Required minimum balance under the dividend retention fund

50

Contributions to the dividend retention fund

250

90

50

$ 35

$ 15

Minimum contribution from the dividend retention fund to Century not required for XOL agreement

200

Dividend Retention Fund Contribution to XOL

302

64

Aggregate reinsurance balances ceded by active ACE companies to Century

1,600

1,500

Liability for Claims and Claims Adjustment Expense

$ 2,100

1,800

Surplus note

$ 100

Westchester and Brandywine Run-off [Member]

Liability for Claims and Claims Adjustment Expense [Line Items]

NICO pro-rata share of reinsurance protection (percent)

75.00%

NICO retention for losses and loss expenses incurred on or before 12/31/1996

$ 721

NICO reinsurance protection on losses and loss expenses incurred on or before 12/31/1996, net of retenion

1,000

NICO reinsurance protection on losses and loss expenses

372

Long Tail [Member]

Liability for Claims and Claims Adjustment Expense [Line Items]

Liability for Claims and Claims Adjustment Expense [Line Items]

(313)

(642)

(486)

Short Tail [Member]

(82)

(150)

(410)

Liability for Claims and Claims Adjustment Expense [Line Items]

(702)

$ (649)

$ (610)

Prior Period Development Percentage Opening Net Unpaid Reserves

$ 31

^[1]

1.40%

1.30%

1.20%

North America Commercial P&C Insurance | Long Tail [Member]

Liability for Claims and Claims Adjustment Expense [Line Items]

$ (672)

$ (668)

$ (395)

North America Commercial P&C Insurance | Short Tail [Member]

31

Liability for Claims and Claims Adjustment Expense [Line Items]

(30)

19

(215)

North America Commercial P&C Insurance | North America Commercial P&C Insurance - Workers' Compensation [Member] | Long Tail [Member]

0

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Multi-Line [Member] | Long Tail [Member]

(303)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Other [Member] | Long Tail [Member]

(26)

(34)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Management Liability [Member] | Long Tail [Member]

77

26

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Professional Liability [Member] | Long Tail [Member]

(217)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Workers' Compensation Insurance [Member] | Long Tail [Member]

(60)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Property and Inland Marine | Short Tail [Member]

(363)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Catastrophe [Member] | Property and Inland Marine | Short Tail [Member]

108

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident years 2014 and prior [Member] | Commercial Excess and Umbrella [Member] | Long Tail [Member]

(36)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Political [Member] | Long Tail [Member]

(83)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident Year 2013 and prior [Member] | Commercial Excess and Umbrella [Member] | Long Tail [Member]

(23)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Foreign Casualty Line [Member] | Long Tail [Member]

(41)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Surety Product Line [Member] | Short Tail [Member]

(40)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member] | Long Tail [Member]

(49)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Surety Product Line [Member] | Short Tail [Member]

(61)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Property and Inland Marine | Short Tail [Member]

(31)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident years 2016 and prior [Member] | Professional Errors and Omissions Insurance [Member] | Long Tail [Member]

152

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident years 2016 and prior [Member] | Multi-Line [Member] | Long Tail [Member]

(67)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident years 2016 and prior [Member] | Environmental lines [Member] | Long Tail [Member]

(41)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident Year 2015 and prior [Member] | Foreign Casualty Line [Member] | Long Tail [Member]

(43)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident Year 2015 and prior [Member] | Medical Portfolios [Member] | Long Tail [Member]

(39)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident Year 2015 and prior [Member] | Multi-Line [Member] | Long Tail [Member]

(24)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident Year 2015 and prior [Member] | Management Liability [Member] | Long Tail [Member]

(36)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident years 2016 - 2019 [Member] | Medical Portfolios [Member] | Long Tail [Member]

(231)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident years 2018 - 2019 [Member] | Accident and Health [Member] | Short Tail [Member]

64

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Workers' Compensation Insurance [Member] | Long Tail [Member]

(37)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Property and Inland Marine | Short Tail [Member]

(62)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident years 2014 - 2018 [Member] | Auto Liability Excess Lines [Member] | Long Tail [Member]

21

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident years 2017 - 2019 | General Liability Coverages | Long Tail [Member]

38

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident year 2017 and prior | Non-catastrophe [Member] | Property and Inland Marine | Short Tail [Member]

48

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Commercial P&C Insurance | Accident year 2017 - 2018 | Catastrophe [Member] | Property and Inland Marine | Short Tail [Member]

(44)

Liability for Claims and Claims Adjustment Expense [Line Items]

(41)

Liability for Claims and Claims Adjustment Expense [Line Items]

Prior Period Development Percentage Opening Net Unpaid Reserves

$ 63

$ (95)

$ 41

^[1]

0.10%

0.20%

0.10%

North America Personal P&C Insurance [Member] | Long Tail [Member]

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Personal P&C Insurance [Member] | Short Tail [Member]

$ 0

Liability for Claims and Claims Adjustment Expense [Line Items]

63

(95)

41

North America Personal P&C Insurance [Member] | Personal Excess [Member] | Short Tail [Member]

(18)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Personal P&C Insurance [Member] | Accident years 2017 - 2018 [Member] | Catastrophe [Member] | Short Tail [Member]

(22)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Personal P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Personal Excess [Member] | Short Tail [Member]

(132)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Personal P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Homeowners and Valuables [Member] | Short Tail [Member]

(26)

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Personal P&C Insurance [Member] | Accident Year 2017 to 2019 [Member] | Homeowners and Valuables [Member] | Short Tail [Member]

82

Liability for Claims and Claims Adjustment Expense [Line Items]

84

Liability for Claims and Claims Adjustment Expense [Line Items]

Prior Period Development Percentage Opening Net Unpaid Reserves

$ (10)

$ (80)

$ (110)

^[1]

0.00%

0.20%

North America Agricultural Insurance | Long Tail [Member]

Liability for Claims and Claims Adjustment Expense [Line Items]

North America Agricultural Insurance | Short Tail [Member]

$ 0

Liability for Claims and Claims Adjustment Expense [Line Items]

(10)

(80)

(110)

9

Liability for Claims and Claims Adjustment Expense [Line Items]

(150)

$ (92)

$ (212)

Prior Period Development Percentage Opening Net Unpaid Reserves

$ 0

^[1]

0.30%

0.20%

0.40%

Overseas General Insurance | Long Tail [Member]

Liability for Claims and Claims Adjustment Expense [Line Items]

$ (49)

$ (68)

$ (67)

Overseas General Insurance | Short Tail [Member]

0

Liability for Claims and Claims Adjustment Expense [Line Items]

(101)

(24)

(145)

Overseas General Insurance | Casualty Lines [Member] | Long Tail [Member]

0

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Financial [Member] | Long Tail [Member]

(94)

(101)

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2017 - 2018 [Member] | Surety Product Line [Member] | Short Tail [Member]

80

52

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2017 - 2018 [Member] | Accident and Health [Member] | Short Tail [Member]

27

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Construction [Member] | Short Tail [Member]

(45)

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2016 and prior [Member] | Casualty Lines [Member] | Long Tail [Member]

23

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2016 and prior [Member] | Marine [Member] | Short Tail [Member]

(143)

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident Year 2015 and prior [Member] | Casualty Lines [Member] | Long Tail [Member]

(36)

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident Year 2015 and prior [Member] | Financial [Member] | Long Tail [Member]

(123)

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2016 - 2018 [Member] | Casualty Lines [Member] | Long Tail [Member]

(61)

(75)

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2016 - 2018 [Member] | Financial [Member] | Long Tail [Member]

22

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident Year 2017 to 2019 [Member] | Casualty Lines [Member] | Long Tail [Member]

127

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2016 - 2019 [Member] | Financial [Member] | Long Tail [Member]

49

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2018 - 2019 [Member] | Accident and Health [Member] | Short Tail [Member]

141

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2018 - 2019 [Member] | Political Risk | Long Tail [Member]

(21)

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance | Accident years 2012 through 2019 | Marine [Member] | Short Tail [Member]

(22)

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance - Casualty [Member] | Europe [Member]

$ (69)

Liability for Claims and Claims Adjustment Expense [Line Items]

Overseas General Insurance - Non-Casualty [Member] | Latin America [Member]

45.00%

Liability for Claims and Claims Adjustment Expense [Line Items]

Global Reinsurance Non-Casualty [Member] | Accident year 2013 to 2020

30.00%

Liability for Claims and Claims Adjustment Expense [Line Items]

Global Reinsurance Non-Casualty [Member] | Accident years 2011 to 2012

82.00%

Liability for Claims and Claims Adjustment Expense [Line Items]

Global Reinsurance Non-Casualty [Member] | accident year 2011 and after

59.00%

Liability for Claims and Claims Adjustment Expense [Line Items]

77.00%

Liability for Claims and Claims Adjustment Expense [Line Items]

$ (29)

$ (50)

Prior Period Development Percentage Opening Net Unpaid Reserves

$ (3)

^[1]

0.10%

Segment Global Reinsurance [Member] | Long Tail [Member]

Liability for Claims and Claims Adjustment Expense [Line Items]

$ (25)

$ (59)

$ (69)

Segment Global Reinsurance [Member] | Short Tail [Member]

(2)

Liability for Claims and Claims Adjustment Expense [Line Items]

(4)

30

19

Segment Global Reinsurance [Member] | Accident Year 2013 and prior [Member] | Other [Member] | Long Tail [Member]

(1)

Liability for Claims and Claims Adjustment Expense [Line Items]

Segment Global Reinsurance [Member] | Accident years 2017 - 2018 [Member] | Catastrophe [Member] | Short Tail [Member]

(59)

Liability for Claims and Claims Adjustment Expense [Line Items]

Corporate Segment [Member]

44

Liability for Claims and Claims Adjustment Expense [Line Items]

Prior Period Development Percentage Opening Net Unpaid Reserves

$ 433

$ 153

$ 45

^[1]

0.90%

0.30%

0.10%

Corporate Segment [Member] | Discontinued Operations [Member]

Liability for Claims and Claims Adjustment Expense [Line Items]

Corporate Segment [Member] | Long Tail [Member]

$ 38

$ 37

Liability for Claims and Claims Adjustment Expense [Line Items]

433

153

$ 45

Corporate Segment [Member] | Short Tail [Member]

0

Liability for Claims and Claims Adjustment Expense [Line Items]

Corporate Segment [Member] | Other [Member]

0

$ 0

Liability for Claims and Claims Adjustment Expense [Line Items]

Corporate Segment [Member] | Other [Member] | Other [Member]

254

Liability for Claims and Claims Adjustment Expense [Line Items]

Corporate Segment [Member] | Asbestos & Environmental [Member] | Long Tail [Member]

27

Liability for Claims and Claims Adjustment Expense [Line Items]

$ 106

$ 116

[1]	Calculated based on the beginning of period consolidated net unpaid losses and loss expenses.

Taxation (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
Taxation (Narrative) (Details) - USD ($) $ in Millions	Jan. 30, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Examination [Line Items]
Unrecognized Tax Benefits		$ 76	$ 47	$ 14
Income Tax Credits and Adjustments		31	19
Valuation allowance		83	114
Unrecognized tax benefits that would affect the effective tax rate		45	28
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense		8	5
Liabilities recorded for tax-related interest and penalties		16	$ 8
Subsequent Event [Member]
Income Tax Examination [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions	$ 23
Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Net operating loss carry-forwards		$ 407
Switzerland
Income Tax Examination [Line Items]
Applicable income tax rates		21.20%	7.83%	7.83%
Foreign Tax Authority [Member]
Income Tax Examination [Line Items]
Foreign tax credit carry-forward		$ 222
Bermuda
Income Tax Examination [Line Items]
Applicable income tax rates		0.00%
UNITED STATES
Income Tax Examination [Line Items]
Applicable income tax rates		21.00%
UNITED KINGDOM
Income Tax Examination [Line Items]
Applicable income tax rates		19.00%

Taxation (Provision For Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Examination [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ 350	$ 440	$ 950
Income (Loss) from Continuing Operations before Income Taxes, Foreign	3,812	4,809	3,707
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	4,162	5,249	4,657
Current tax expense	928	908	652
Deferred tax expense	(299)	(113)	43
Provision for income taxes	629	795	695
Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Current tax expense	52	29	89
Deferred tax expense	2	11	3
Foreign Tax Authority [Member]
Income Tax Examination [Line Items]
Current tax expense	876	879	563
Deferred tax expense	$ (301)	$ (124)	$ 40

Amount after tax of income (loss) from continuing operations including portion attributable to the noncontrolling interest.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8924-108599

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569616-111683

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

Taxation (Reconciliation Of The Difference Between The Provision for Income Taxes and the Expected Tax Provision at Swiss Statutory Income Tax Rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Expected tax provision at Swiss statutory rate	$ 880	$ 411	$ 365
Taxes on earnings subject to rates other that Swiss statutory rate	(337)	376	372
Tax exempt interest and dividends received deduction, net of proration	(41)	(49)	(75)
Net witholding taxes	67	40	33
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount	(10)	(12)	(19)
Income tax benefit related to 2017 Tax Act	0	0	(25)
Other	70	29	44
Provision for income taxes	$ 629	$ 795	$ 695

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

Taxation (Components Of Net Deferred Tax Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred Tax Assets, Gross [Abstract]
Loss reserve discount	$ 884	$ 826
Unearned premium reserve	496	519
Foreign tax credits	222	247
Provision for uncollectible balances	46	37
Loss carry-forwards	123	143
Debt related amounts	69	74
Compensation related amounts	281	261
Cumulative translation adjustments	120	33
Unrealized depreciation on investments	75	0
Deferred Tax Asset, Lease Liability	121	140
Total deferred tax assets	2,437	2,280
Deferred Tax Liabilities, Gross [Abstract]
Deferred policy acquisition costs	522	588
VOBA and other intangible assets	1,425	1,468
Un-remitted foreign earnings	77	73
Investments	0	40
Unrealized appreciation on investments	957	470
Depreciation	123	157
Leasing Arrangements	111	129
Deferred Tax Liabilities, Other	31	45
Deferred Tax Liabilities, Gross	3,246	2,970
Valuation allowance	83	114
Deferred Tax Liabilities, Net	$ (892)	$ (804)

Taxation (Reconciliation of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits, beginning of year	$ 47	$ 14
Additions based on tax provisions related to the current year	5	12
Additions based on tax positions related to prior years	24	23
Reductions for the lapse of the applicable statutes of limitations	0	(2)
Unrecognized Tax Benefits, end of year	$ 76	$ 47

Taxation Taxation (Summary Of Income Tax Examinations) (Details)	12 Months Ended
	Dec. 31, 2020
Earliest Tax Year [Member] \| Switzerland
Income Tax Examination [Line Items]
Open Tax Year	2016
Earliest Tax Year [Member] \| AUSTRALIA
Income Tax Examination [Line Items]
Open Tax Year	2014
Earliest Tax Year [Member] \| CANADA
Income Tax Examination [Line Items]
Open Tax Year	2012
Earliest Tax Year [Member] \| FRANCE
Income Tax Examination [Line Items]
Open Tax Year	2018
Earliest Tax Year [Member] \| GERMANY
Income Tax Examination [Line Items]
Open Tax Year	2015
Earliest Tax Year [Member] \| ITALY
Income Tax Examination [Line Items]
Open Tax Year	2010
Earliest Tax Year [Member] \| MEXICO
Income Tax Examination [Line Items]
Open Tax Year	2014
Earliest Tax Year [Member] \| SPAIN
Income Tax Examination [Line Items]
Open Tax Year	2012
Earliest Tax Year [Member] \| UNITED KINGDOM
Income Tax Examination [Line Items]
Open Tax Year	2015
Earliest Tax Year [Member] \| UNITED STATES
Income Tax Examination [Line Items]
Open Tax Year	2014
Latest Tax Year [Member] \| Switzerland
Income Tax Examination [Line Items]
Open Tax Year	2020
Latest Tax Year [Member] \| AUSTRALIA
Income Tax Examination [Line Items]
Open Tax Year	2020
Latest Tax Year [Member] \| CANADA
Income Tax Examination [Line Items]
Open Tax Year	2020
Latest Tax Year [Member] \| FRANCE
Income Tax Examination [Line Items]
Open Tax Year	2020
Latest Tax Year [Member] \| GERMANY
Income Tax Examination [Line Items]
Open Tax Year	2020
Latest Tax Year [Member] \| ITALY
Income Tax Examination [Line Items]
Open Tax Year	2020
Latest Tax Year [Member] \| MEXICO
Income Tax Examination [Line Items]
Open Tax Year	2020
Latest Tax Year [Member] \| SPAIN
Income Tax Examination [Line Items]
Open Tax Year	2020
Latest Tax Year [Member] \| UNITED KINGDOM
Income Tax Examination [Line Items]
Open Tax Year	2020
Latest Tax Year [Member] \| UNITED STATES
Income Tax Examination [Line Items]
Open Tax Year	2020

Debt (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Mar. 31, 2000
INA Senior Notes Due November 2020 [Member] \| Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 1,300.0
Long-term debt stated interest rate	2.30%
Senior Notes \| INA Senior Notes Due September 2030
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 1,000.0
Long-term debt stated interest rate	1.375%
Trust Preferred Securities \| INA capital securities due 2030
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 309.0	$ 300.0
ACE Capital Trust II common securities purchased		$ 9.2
Long-term debt stated interest rate	9.70%	9.70%
Unsecured Debt \| INA Senior Notes Due August 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 100.0
Long-term debt stated interest rate	8.875%

Debt (Schedule of Debt Outstanding) (Details) € in Millions, $ in Millions	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Mar. 31, 2000 USD ($)
Debt Instrument [Line Items]
Short-term debt	$ 0		$ 1,299
Long-term debt	14,948		13,559
Trust preferred securities	308		308
Senior Notes
Debt Instrument [Line Items]
Long-term debt	14,948		13,559
Senior Notes \| INA Senior Notes Due November 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	998		997
Debt Instrument, Face Amount	$ 1,000
Long-term debt stated interest rate	2.875%	2.875%
Make Whole Premium Additional Percent	20.00%	20.00%
Senior Notes \| INA Senior Notes Due March 2023 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 474		473
Debt Instrument, Face Amount	$ 475
Long-term debt stated interest rate	2.70%	2.70%
Make Whole Premium Additional Percent	10.00%	10.00%
Senior Notes \| INA Senior Notes Due May 2024 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 698		697
Debt Instrument, Face Amount	$ 700
Long-term debt stated interest rate	3.35%	3.35%
Make Whole Premium Additional Percent	15.00%	15.00%
Senior Notes \| INA Senior Notes Due December 2024 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 841		776
Debt Instrument, Face Amount \| €		€ 700
Long-term debt stated interest rate	0.30%	0.30%
Make Whole Premium Additional Percent	15.00%	15.00%
Senior Notes \| INA Senior Notes Due March 2025 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 797		796
Debt Instrument, Face Amount	$ 800
Long-term debt stated interest rate	3.15%	3.15%
Make Whole Premium Additional Percent	15.00%	15.00%
Senior Notes \| INA Senior Notes Due May 2026 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1,493		1,492
Debt Instrument, Face Amount	$ 1,500
Long-term debt stated interest rate	3.35%	3.35%
Make Whole Premium Additional Percent	20.00%	20.00%
Senior Notes \| INA Senior Notes Due June 2027 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 691		635
Debt Instrument, Face Amount \| €		€ 575
Long-term debt stated interest rate	0.875%	0.875%
Make Whole Premium Additional Percent	20.00%	20.00%
Senior Notes \| INA Senior Notes Due March 2028 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1,079		993
Debt Instrument, Face Amount \| €		€ 900
Long-term debt stated interest rate	1.55%	1.55%
Make Whole Premium Additional Percent	15.00%	15.00%
Senior Notes \| INA Senior Notes Due December 2029 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 840		775
Debt Instrument, Face Amount \| €		€ 700
Long-term debt stated interest rate	0.875%	0.875%
Make Whole Premium Additional Percent	20.00%	20.00%
Senior Notes \| INA Senior Notes Due September 2030
Debt Instrument [Line Items]
Long-term debt	$ 991		0
Debt Instrument, Face Amount	$ 1,000
Long-term debt stated interest rate	1.375%	1.375%
Make Whole Premium Additional Percent	15.00%	15.00%
Senior Notes \| INA Senior Notes Due June 2031 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 687		633
Debt Instrument, Face Amount \| €		€ 575
Long-term debt stated interest rate	1.40%	1.40%
Make Whole Premium Additional Percent	25.00%	25.00%
Senior Notes \| INA Senior Notes Due November 2031
Debt Instrument [Line Items]
Make Whole Premium Additional Percent	25.00%	25.00%
Senior Notes \| INA Senior Notes Due May 2036 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 298		297
Debt Instrument, Face Amount	$ 300
Long-term debt stated interest rate	6.70%	6.70%
Make Whole Premium Additional Percent	20.00%	20.00%
Senior Notes \| INA Senior Notes Due May 2037 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 945		953
Debt Instrument, Face Amount	$ 800
Long-term debt stated interest rate	6.00%	6.00%
Make Whole Premium Additional Percent	20.00%	20.00%
Senior Notes \| INA Senior Notes Due March 2038 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1,077		992
Debt Instrument, Face Amount \| €		€ 900
Long-term debt stated interest rate	2.50%	2.50%
Make Whole Premium Additional Percent	25.00%	25.00%
Senior Notes \| INA Senior Notes Due May 2038 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 743		751
Debt Instrument, Face Amount	$ 600
Long-term debt stated interest rate	6.50%	6.50%
Make Whole Premium Additional Percent	30.00%	30.00%
Senior Notes \| INA Senior Notes Due March 2043 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 470		470
Debt Instrument, Face Amount	$ 475
Long-term debt stated interest rate	4.15%	4.15%
Make Whole Premium Additional Percent	15.00%	15.00%
Senior Notes \| INA Senior Notes Due November 2045 [Member]
Debt Instrument [Line Items]
Long-term debt	$ 1,484		1,483
Debt Instrument, Face Amount	$ 1,500
Long-term debt stated interest rate	4.35%	4.35%
Make Whole Premium Additional Percent	25.00%	25.00%
Trust Preferred Securities \| INA capital securities due 2030
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 309			$ 300
Long-term debt stated interest rate	9.70%	9.70%		9.70%
Trust preferred securities	$ 308		308
Unsecured Debt \| INA Senior Notes Due August 2029 [Member]
Debt Instrument [Line Items]
Long-term debt	100		100
Debt Instrument, Face Amount	$ 100
Long-term debt stated interest rate	8.875%	8.875%
Unsecured Debt \| INA Senior Notes Due November 2031
Debt Instrument [Line Items]
Long-term debt	$ 242		246
Debt Instrument, Face Amount	$ 200
Long-term debt stated interest rate	6.80%	6.80%
Repurchase agreements
Debt Instrument [Line Items]
Short-term debt	$ 1,405		$ 1,416
Weighted average interest rate on short-term debt	0.30%	0.30%	2.20%
Senior Notes \| INA Senior Notes Due November 2020 [Member]
Debt Instrument [Line Items]
Short-term debt	$ 0		$ 1,298
Debt Instrument, Face Amount	$ 1,300
Long-term debt stated interest rate	2.30%	2.30%
Make Whole Premium Additional Percent	15.00%	15.00%
Senior Notes \| Other Short Term Debt due September 2020 [Member]
Debt Instrument [Line Items]
Short-term debt	$ 0		$ 1
Long-term debt stated interest rate	2.75%	2.75%

Commitments, contingencies, and guarantees (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2010
Financial Instruments Owned and Pledged as Collateral [Line Items]
Derivative Liability, Fair Value, Amount Subject to a Master Netting Agreement	$ 30	$ 75
Securities Sold under Agreements to Repurchase	$ 1,405	$ 1,416
Concentration Risk Percentage Marsh	12.00%	12.00%	10.00%
Purchase Commitment, Remaining Minimum Amount Committed	$ 605
Carrying value of limited partnerships and partially-owned investment companies included in other investments	6,500	$ 4,700
Funding commitments relating to limited partnerships and partially-owned investment companies	3,200	3,300
Line of Credit Facility, Current Borrowing Capacity				$ 4,000
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases	1,900
Operating Lease, Right-of-Use Asset	473	551
Operating Lease, Liability	$ 517	603
Operating Lease, Weighted Average Remaining Lease Term	4 years 10 months 24 days
Operating Lease, Weighted Average Discount Rate, Percent	2.60%
Total rental expense related to operating leases	$ 152	171	$ 169
Deposit Assets	$ 107	$ 93
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities	us-gaap:OtherLiabilities
Repurchase agreements	$ 1,405	$ 1,416
Letter of Credit [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Line of Credit Facility, Amount Outstanding	$ 1,700
Huatai Group [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Ownership Percentage	47.10%
CHINA \| Huatai Group [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Equity method investment, additional 22.4 ownership percentage obtained		22.40%
Ownership Percentage	47.00%	31.00%

Commitments, contingencies, and guarantees (Balance Sheet Locations, Fair Values In Asset Or (Liability) Position, And Notional Values/Payment Provisions Of Derivative Instruments) (Detail) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

$ 5,713

$ 5,373

Foreign currency forward contracts [Member]

4,567

4,199

Futures contracts on notes and bonds [Member]

2,807

2,579

Convertible Securities [Member]

1,749

1,615

Futures contracts on equities

11

5

709

613

Other Derivative Instruments [Member]

16

63

Guaranteed Minimum Income Benefit

725

676

Accounts Payable and Accrued Liabilities [Member]

1,658

1,510

Accounts Payable and Accrued Liabilities [Member] | Foreign currency forward contracts [Member]

(52)

(93)

Accounts Payable and Accrued Liabilities [Member] | Futures contracts on notes and bonds [Member]

(49)

(78)

Accounts Payable and Accrued Liabilities [Member] | Convertible Securities [Member]

(3)

(15)

Accounts Payable and Accrued Liabilities [Member] | Futures contracts on equities

^[1]

0

Accounts Payable and Accrued Liabilities [Member] | Other

^[2]

(17)

(13)

Accounts Payable and Accrued Liabilities [Member] | Other Derivative Instruments [Member]

0

(17)

(13)

Other Assets [Member]

Other Assets [Member] | Foreign currency forward contracts [Member]

44

28

Other Assets [Member] | Futures contracts on notes and bonds [Member]

22

11

Other Assets [Member] | Futures contracts on equities

13

Other Assets [Member] | Other

^[2]

0

Other Assets [Member] | Other Derivative Instruments [Member]

0

2

Other Assets [Member] | Guaranteed Minimum Income Benefit

0

2

Accounts Payable Future Policy Benefits [Member] | Guaranteed Minimum Income Benefit

0

Available-for-sale Securities [Member] | Convertible Securities [Member]

(1,089)

(897)

Guaranteed Minimum Income Benefit | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]

^[1]

9

4

Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross

$ 1,089

$ 897

[1]	Includes fair value of embedded derivatives.
[2]	Related to GMDB and GLB book of business.(3)Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.

Commitments, contingencies, and guarantees Commitments, Contingencies, And Guarantees (Transactions accounted for as secured borrowings) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	$ 1,844	$ 994
Collateral held under securities lending agreements	1,844	994
Maturity Overnight [Member] \| Cash
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	551	346
Maturity Overnight [Member] \| U.S. Treasury and agency
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	148	6
Maturity Overnight [Member] \| Foreign [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	1,032	595
Maturity Overnight [Member] \| Corporate securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	30	5
Maturity Overnight [Member] \| Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	4	18
Maturity Overnight [Member] \| Equity securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	$ 79	$ 24

Commitments, contingencies, and guarantees Commitments, contingencies, and guarantees (Collateral pledged under repurchase agreements) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	$ 1,462	$ 1,464
Securities Sold under Agreements to Repurchase	1,405	1,416
Cash
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	4	2
US Treasury and Government [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	106	107
Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	1,352	1,355
Repurchase Agreements [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Secured Borrowings, Gross, Difference, Amount	57	48
Maturity Less than 30 Days [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements		508
Maturity Less than 30 Days [Member] \| Cash
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements		2
Maturity Less than 30 Days [Member] \| US Treasury and Government [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements		107
Maturity Less than 30 Days [Member] \| Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements		399
Maturity 30 to 90 Days [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	481	476
Maturity 30 to 90 Days [Member] \| Cash
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	0	0
Maturity 30 to 90 Days [Member] \| US Treasury and Government [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	0	0
Maturity 30 to 90 Days [Member] \| Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	481	476
Maturity Greater than 90 Days [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	981	480
Maturity Greater than 90 Days [Member] \| Cash
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	4	0
Maturity Greater than 90 Days [Member] \| US Treasury and Government [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	106	0
Maturity Greater than 90 Days [Member] \| Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Collateral pledged under repurchase agreements	$ 871	$ 480

Commitments, contingencies, and guarantees (Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations) (Detail) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Derivative Instruments, Gain (Loss) [Line Items]

Foreign currency forward contracts [Member]

$ (228)

$ (585)

$ (330)

Derivative Instruments, Gain (Loss) [Line Items]

Interest Rate Swap [Member]

65

(79)

3

Derivative Instruments, Gain (Loss) [Line Items]

All Other Futures Contracts And Options [Member]

0

(270)

(115)

Derivative Instruments, Gain (Loss) [Line Items]

Convertible Securities [Member]

16

(88)

39

Derivative Instruments, Gain (Loss) [Line Items]

Investment And Embedded Derivative Instruments [Member]

^[1]

0

2

(2)

Derivative Instruments, Gain (Loss) [Line Items]

Derivative Instruments, Gain (Loss) [Line Items]

81

(435)

(75)

GLB

Futures contracts on equities

(202)

(4)

(248)

Derivative Instruments, Gain (Loss) [Line Items]

Derivative Instruments, Gain (Loss) [Line Items]

^[2]

(108)

(138)

(4)

Other Derivatives

Guaranteed Living Benefit And Other Derivative Instruments [Member]

1

(8)

(3)

Derivative Instruments, Gain (Loss) [Line Items]

Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]

$ (309)

$ (150)

$ (255)

[1]	Includes embedded derivatives.
[2]	Related to GMDB and GLB book of business.

Commitments, contingencies, and guarantees (Future Minimum Lease Payments) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
2020	$ 150
2021	123
2022	96
2023	68
2024	38
Thereafter	75
Total undiscounted lease payments	550
Present value adjustment	33
Operating Lease, Liability	$ 517	$ 603

Shareholders' equity (Detail) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020 SFr / shares shares	Dec. 31, 2019 SFr / shares shares	Dec. 31, 2018 shares	Feb. 01, 2021 USD ($)	Nov. 19, 2020 USD ($)	May 31, 2020 $ / shares	May 20, 2020 $ / shares	Nov. 21, 2019 USD ($)	May 31, 2019 $ / shares	Dec. 01, 2018 USD ($)	May 31, 2018 $ / shares	Dec. 31, 2017 shares	Dec. 21, 2017 USD ($)
Stockholders' Equity Note [Abstract]
Common Stock, Dividend Rate Approved \| $ / shares							$ 0.78		$ 0.75		$ 0.73
The number of votes associated with one Common Share	one
Annual dividend per share approved by shareholders \| $ / shares						$ 3.12			$ 3.00		$ 2.92
Authorized Share Capital [Line Items]
Common Shares, par value \| SFr / shares	SFr 24.15	SFr 24.15
Common Shares, shares issued \| shares	477,605,264	479,783,864	479,783,864									479,783,864
Treasury Stock, Shares, Retired \| shares	2,178,600	0	0
The maximum ownership percentage for voting allowed for any one shareholder	10.00%
General Purpose
Authorized Share Capital [Line Items]
Authorized share capital for future issuance \| shares	200,000,000
Issuance of Debt
Authorized Share Capital [Line Items]
Authorized share capital for future issuance \| shares	33,000,000
Employee Benefit Plans
Authorized Share Capital [Line Items]
Authorized share capital for future issuance \| shares	25,410,929
2018 Stock Repurchase Plan [Member] [Domain]
Authorized Share Capital [Line Items]
Stock repurchase program authorized amount													$ 1,000
2019 Stock Repurchase Plan [Member]
Authorized Share Capital [Line Items]
Stock repurchase program authorized amount										$ 1,500
Nov 2019 Stock Repurchase Plan [Member]
Authorized Share Capital [Line Items]
Stock repurchase program authorized amount								$ 1,500
Nov 2020 Stock Repurchase Plan [Member]
Authorized Share Capital [Line Items]
Stock repurchase program authorized amount					$ 1,500
Subsequent Event [Member] \| Nov 2020 Stock Repurchase Plan [Member]
Authorized Share Capital [Line Items]
Stock repurchase program authorized amount				$ 2,500
CB_Increase(Decrease)StockRepurchaseProgramAuthorizedAmount				$ 1,000

Shareholders' equity Schedule of Dividends Declared (Details)	12 Months Ended
	Dec. 31, 2020 SFr / shares	Dec. 31, 2020 $ / shares	Dec. 31, 2019 SFr / shares	Dec. 31, 2019 $ / shares	Dec. 31, 2018 SFr / shares	Dec. 31, 2018 $ / shares
Switzerland, Francs
Dividends Declared [Line Items]
Total dividend distributions per common share \| SFr / shares	SFr 2.89		SFr 2.94		SFr 2.84
United States of America, Dollars
Dividends Declared [Line Items]
Total dividend distributions per common share \| $ / shares		$ 3.09		$ 2.98		$ 2.90

Shareholders' equity (Rollforward Of Changes In Common Stock Shares Issued And Outstanding) (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Shares issued, Beginning of year	479,783,864	479,783,864	479,783,864
Treasury Stock, Shares, Retired	(2,178,600)	0	0
Shares issued, End of year	477,605,264	479,783,864	479,783,864
Common Shares in treasury, end of year	(26,872,639)	(27,812,297)	(20,580,486)	(15,950,685)
Stock Issued During Period, Shares, New Issues	2,345,208	3,210,427	3,089,234
Treasury Stock, Shares, Acquired	(3,584,150)	(10,442,238)	(7,719,035)
Shares issued and outstanding, end of year	450,732,625	451,971,567	459,203,378

Shareholders' equity Repurchase of Common Shares (Details) - USD ($) $ in Millions	2 Months Ended	12 Months Ended
	Feb. 24, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased		3,584,150	10,442,238	7,719,035
Common Shares repurchased		$ 516	$ 1,531	$ 1,021
Subsequent Event [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased	1,971,000
Common Shares repurchased	$ 327

Share-based compensation (Narrative) (Detail) - USD ($)	12 Months Ended
Share-based compensation (Narrative) (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to the unvested share-based awards	$ 199,000,000
Weighted-average expected recognition period for the unrecognized compensation expense	1 year
Weighted average remaining contractual term for stock options outstanding	6 years
Weighted-average remaining contractual term for stock options exercisable	4 years 9 months 18 days
Cash received from exercise of stock options	$ 100,000,000
Restricted stock awards granted to non-management directors	27,679	19,019	20,784
Amounts paid during period by employees for the purchase of shares under the ESPP	$ 45,000,000	$ 41,000,000	$ 37,000,000
Number of shares purchased during period by employees pursuant to the provisions of the ESPP	383,751	321,800	347,116
Discounted purchase price from market price for the ESPP	85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate for the ESPP	10.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Stock Purchase Plan Authorized Amount	$ 25,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	3 years
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	3 years
Stock option term in years	10 years
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	4 years
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	1 year
Number of deferred restricted stock units	166,624
Restricted Stock Units (RSUs) \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	1 year
Restricted Stock Units (RSUs) \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	3 years
ACE Limited 2004 Long-Term Incentive Plan [Member] \| Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award	4 years
Common shares \| Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares authorized for issuance under plan	6,500,000
Common Stock, Capital Shares Reserved for Future Issuance	1,402,017
Common shares \| Chubb Limited 2016 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares authorized for issuance under plan	19,500,000
Common Stock, Capital Shares Reserved for Future Issuance	7,576,239

Share-based compensation (Pre-tax and After-tax Share-based Compensation Expense) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Share-based Payment Arrangement, Expense, Tax Benefit

$ 10

$ 12

$ 19

Restricted stock

Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]

Share-based compensation expense, pre-tax

210

224

235

Share-based compensation expense, after-tax

164

180

178

Stock options

Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]

Share-based compensation expense, pre-tax

45

42

50

Share-based compensation expense, after-tax

^[1]

$ 38

$ 39

$ 40

[1]	The windfall tax benefit recorded to Income tax expense in the Consolidated statement of operations was $10 million, $12 million, and $19 million for the years ended December 31, 2020, 2019, and 2018, respectively.

Share-based compensation (Weighted Average Assumptions for Option Grants) (Details) - Options	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	2.10%	2.20%	2.00%
Expected volatility	18.00%	16.00%	23.20%
Risk-free interest rate	1.20%	2.60%	2.70%
Expected life	5 years 8 months 12 days	5 years 8 months 12 days	5 years 8 months 12 days

Share-based compensation (Rollforward Of Company's Stock Options) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Options, Weighted-Average Fair Value and Total Intrinsic Value [Abstract]
Weighted-average fair value of stock options granted (US$ per share)	$ 19.89	$ 18.76	$ 29.71
Total intrinsic value of options exercised	$ 76	$ 122	$ 71
Total intrinsic value of options outstanding	331
Total intrinsic value of options exercisable	$ 293
Number of Options [Roll Forward]
Number of option outstanding, beginning of period	10,885,257	11,007,722	10,433,316
Number of options granted	1,958,279	2,073,940	1,842,690
Number of options exercised	(1,158,633)	(1,944,604)	(1,065,384)
Number of options forfeited	(206,720)	(251,801)	(202,900)
Number of option outstanding, end of period	11,478,183	10,885,257	11,007,722
Number of options exercisable	7,792,343
Weighted-Average Exercise Price [Roll Forward]
Weighted-average exercise price of options outstanding, beginning of period (US$ oer share)	$ 116.79	$ 108.25	$ 99.20
Weighted-average exercise price of options granted (US$ per share)	150.10	133.90	143.07
Weighted-average exercise price of options exercised (US$ per share)	86.90	84.13	73.57
Weighted average exercise price of options forfeited (US$ per share)	138.77	136.87	133.92
Weighted-average exercise price of options outstanding, end of period (US$ oer share	125.09	$ 116.79	$ 108.25
Weighted average exercise price of options exercisable (US$ per share)	$ 116.35

Share-based compensation (Rollforward Of Company's Restricted Stock) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted stock
Number of Restricted Stock [Roll Forward]
Number of unvested restricted stock, beginning of period	3,294,010	3,294,849	4,709,442
Number of restricted stock, granted	1,425,667	1,492,900	1,326,979
Number of restricted stock, vested and issued	(1,304,308)	(1,292,864)	(2,545,090)
Number of restricted stock, forfeited	(152,074)	(200,875)	(196,482)
Number of unvested restricted stock, end of period	3,263,295	3,294,010	3,294,849
Weighted-Average Grant-Day Fair Value [Roll Forward]
Weighted average grant-day fair value of unvested restricted stock outstanding, beginning of period (US$ per share)	$ 136.20	$ 134.17	$ 121.16
Weighted average grant-day fair value of restricted stock, granted (US$ per share)	148.56	134.38	142.76
Weighted average grant-day fair value of restricted stock, vested and issued (US$ per share)	134.02	129.18	114.83
Weighted average grant-day fair value of restricted stock, forfeited (US$ per share)	140.72	135.98	131.06
Weighted average grant-day fair value of unvested restricted stock outstanding, end of period (US$ per share)	$ 142.32	$ 136.20	$ 134.17
Performance Shares
Number of Restricted Stock [Roll Forward]
Number of unvested restricted stock, beginning of period	876,212	911,230	975,497
Number of restricted stock, granted	186,291	212,059	180,065
Number of restricted stock, vested and issued	(490,185)	(196,640)	(244,332)
Number of restricted stock, forfeited	0	(50,437)	0
Number of unvested restricted stock, end of period	572,318	876,212	911,230
Weighted-Average Grant-Day Fair Value [Roll Forward]
Weighted average grant-day fair value of unvested restricted stock outstanding, beginning of period (US$ per share)	$ 131.16	$ 127.27	$ 118.28
Weighted average grant-day fair value of restricted stock, granted (US$ per share)	151.14	133.90	143.07
Weighted average grant-day fair value of restricted stock, vested and issued (US$ per share)	125.66	115.62	103.03
Weighted average grant-day fair value of restricted stock, forfeited (US$ per share)	0	132.36	0
Weighted average grant-day fair value of unvested restricted stock outstanding, end of period (US$ per share)	$ 142.38	$ 131.16	$ 127.27

Postretirement benefits (Narrative) (Details) - USD ($) $ in Millions		12 Months Ended
	Oct. 31, 2016	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Expenses recognized during period under the defined contributions plans		$ 211	$ 171	$ 171
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation		5,100	4,600
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year		20
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		120	152	143
Actuarial Loss (gain)		1	3
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation		23	25
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year		1
Defined Benefit Plan, Plan Amendment [Abstract]
(Increase) decrease in other comprehensive income, curtailment		0	0	3
Amortization of Prior Service Cost (Credit)		$ 83	84	85
Defined Benefit Plan, Equity Securities [Member] \| Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Percentage		55.00%
Defined Benefit Plan, Equity Securities [Member] \| Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Percentage		65.00%
UNITED STATES \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		$ 3,739	3,301	2,784
Actuarial Loss (gain)		441	443
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation		3,967	3,569
Defined Benefit Plan, Plan Amendment [Abstract]
(Increase) decrease in other comprehensive income, curtailment		0	0	0
Amortization of Prior Service Cost (Credit)		0	0	0
UNITED STATES \| Postretirement Health Coverage [Member]
Defined Benefit Plan, Plan Amendment [Abstract]
Effect of Plan Amendment on Accumulated Benefit Obligation	$ 383
Amortization of Prior Service Cost (Credit)		79	79	80
Remaining Balance of Change in Benefit Obligation For Plan Amendment		26
UNITED STATES \| Postretirement Health Coverage [Member] \| Subject to Amortization [Member]
Defined Benefit Plan, Plan Amendment [Abstract]
Effect of Plan Amendment on Accumulated Benefit Obligation	$ 410
Non - U.S. \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount		1,284	1,141	1,008
Actuarial Loss (gain)		135	124
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation		593	173
Defined Benefit Plan, Plan Amendment [Abstract]
(Increase) decrease in other comprehensive income, curtailment		(1)	(3)	0
Amortization of Prior Service Cost (Credit)		$ 0	$ 0	$ 0

Postretirement benefits Schedule of Net Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service Cost	$ 4	$ 60	$ 69
Pension Plan [Member] \| Non - U.S.
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation, beginning of year	1,042	942
Service Cost	4	11	12
Interest Cost	22	27	27
Actuarial Loss (gain)	135	124
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(31)	(39)
Curtailments	(2)	(4)
Settlements, Benefit obligations	0	(61)
Foreign currency revaluation, benefit obligations	29	42
Benefit Obligation, end of year	1,199	1,042	942
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	1,141	1,008
Actual Return on Plan Assets	126	169
Employer Contributions	19	16
Benefits Paid	(31)	(39)
Settlements	0	(61)
Foreign currency revaluation, Plan Assets	29	48
Plan assets at fair value, end of year	1,284	1,141	1,008
Defined Benefit Plan, Funded (Unfunded) Status of Plan	85	99
Pension Plan [Member] \| UNITED STATES
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation, beginning of year	3,569	3,092
Service Cost	0	49	57
Interest Cost	99	118	105
Actuarial Loss (gain)	441	443
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(127)	(121)
Curtailments	0	0
Settlements, Benefit obligations	(15)	(12)
Foreign currency revaluation, benefit obligations	0	0
Benefit Obligation, end of year	3,967	3,569	3,092
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	3,301	2,784
Actual Return on Plan Assets	563	636
Employer Contributions	17	14
Benefits Paid	(127)	(121)
Settlements	(15)	(12)
Foreign currency revaluation, Plan Assets	0	0
Plan assets at fair value, end of year	3,739	3,301	2,784
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(228)	(268)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit Obligation, beginning of year	103	113
Service Cost	1	0	1
Interest Cost	2	4	3
Actuarial Loss (gain)	1	3
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(20)	(17)
Curtailments	0	0
Settlements, Benefit obligations	0	0
Foreign currency revaluation, benefit obligations	(1)	0
Benefit Obligation, end of year	86	103	113
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	152	143
Actual Return on Plan Assets	6	9
Employer Contributions	1	0
Benefits Paid	(39)	0
Settlements	0	0
Foreign currency revaluation, Plan Assets	0	0
Plan assets at fair value, end of year	120	152	$ 143
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ 34	$ 49

Postretirement benefits Schedule of amounts recognized in AOCI on a pretax basis (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Pension Plan [Member] \| Non - U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial loss (gain)	$ 163	$ 110
Prior Service Cost (benefit)	9	10
Total	172	120
Pension Plan [Member] \| UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial loss (gain)	78	(21)
Prior Service Cost (benefit)	0	0
Total	78	(21)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net actuarial loss (gain)	(5)	(3)
Prior Service Cost (benefit)	(31)	(114)
Total	$ (36)	$ (117)

Postretirement benefits Schedule of Benefit Obligation in Excess of FV (Details) - Pension Plan [Member] - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation	$ 3,967	$ 3,569
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets	3,739	3,301
Net Funded Status With PBO in Excess Of Plan Assets	(228)	(268)
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	3,967	3,569
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets	3,739	3,301
Non - U.S.
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation	629	236
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets	568	175
Net Funded Status With PBO in Excess Of Plan Assets	(61)	(61)
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	593	173
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets	$ 565	$ 140

Postretirement benefits Schedule of assumptions used to determine benefit obligation (Details)	Dec. 31, 2020	Dec. 31, 2019
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit Obligation, Discount Rate	1.36%	2.70%
Non - U.S. \| Pension Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit Obligation, Discount Rate	1.80%	2.39%
Benefit Obligation, Rate of Compensation Increase	3.24%	3.26%
UNITED STATES \| Pension Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Benefit Obligation, Discount Rate	2.32%	3.20%
Interest crediting rate	4.10%	4.10%

Postretirement benefits Schedule of net periodic benefit costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Total (increase) decrease in other comprehensive (Income) Loss	$ 232	$ 76	$ 321
Pension Plan [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	4	60	69
Defined Benefit Plan, Non Service (Benefit) Cost	(140)	(84)	(124)
Net Periodic Benefit Cost	(136)	(24)	(55)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	1	0	1
Interest Cost	2	4	3
Expected Return on Plan Assets	(5)	(4)	(5)
Amortization of (Gains) Losses	0	0	0
Amortization of Prior Service Cost (Credit)	(83)	(84)	(85)
Recognized Net (Gain) Loss Due to Curtailments	0	0	(2)
Recognized Net (Gain) Loss Due to Settlements	0	0	0
Defined Benefit Plan, Non Service (Benefit) Cost	(86)	(84)	(89)
Net Periodic Benefit Cost	(85)	(84)	(88)
(Increase) decrease in Other Comprehensive Income (Loss), Net Actuarial (Gain) Loss)	(2)	(2)	(11)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax	0	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	0	0	(1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	83	84	85
(Increase) decrease in other comprehensive income, curtailment	0	0	3
(Increase) decrease in other comprehensive income, settlement	0	0	0
Total (increase) decrease in other comprehensive (Income) Loss	81	82	76
Losses and loss expenses [Member] \| Pension Plan [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	0	6	7
Defined Benefit Plan, Non Service (Benefit) Cost	(12)	(7)	(10)
Losses and loss expenses [Member] \| Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	0	0	0
Defined Benefit Plan, Non Service (Benefit) Cost	(9)	(8)	(9)
General and Administrative Expense [Member] \| Pension Plan [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	4	54	62
Defined Benefit Plan, Non Service (Benefit) Cost	(128)	(77)	(114)
General and Administrative Expense [Member] \| Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	1	0	1
Defined Benefit Plan, Non Service (Benefit) Cost	(77)	(76)	(80)
Non - U.S. \| Pension Plan [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	4	11	12
Interest Cost	22	27	27
Expected Return on Plan Assets	(41)	(45)	(50)
Amortization of (Gains) Losses	2	3	1
Amortization of Prior Service Cost (Credit)	0	0	0
Recognized Net (Gain) Loss Due to Curtailments	(1)	(1)	0
Recognized Net (Gain) Loss Due to Settlements	0	1	3
Defined Benefit Plan, Non Service (Benefit) Cost	(18)	(15)	(19)
Net Periodic Benefit Cost	(14)	(4)	(7)
(Increase) decrease in Other Comprehensive Income (Loss), Net Actuarial (Gain) Loss)	56	6	34
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax	0	1	3
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	(2)	(3)	(1)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	(1)	0	0
(Increase) decrease in other comprehensive income, curtailment	(1)	(3)	0
(Increase) decrease in other comprehensive income, settlement	0	(1)	(3)
Total (increase) decrease in other comprehensive (Income) Loss	52	0	33
UNITED STATES \| Pension Plan [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	0	49	57
Interest Cost	99	118	105
Expected Return on Plan Assets	(224)	(189)	(212)
Amortization of (Gains) Losses	0	0	0
Amortization of Prior Service Cost (Credit)	0	0	0
Recognized Net (Gain) Loss Due to Curtailments	0	0	0
Recognized Net (Gain) Loss Due to Settlements	3	2	2
Defined Benefit Plan, Non Service (Benefit) Cost	(122)	(69)	(105)
Net Periodic Benefit Cost	(122)	(20)	(48)
(Increase) decrease in Other Comprehensive Income (Loss), Net Actuarial (Gain) Loss)	102	(4)	214
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax	0	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	0	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	0	0	0
(Increase) decrease in other comprehensive income, curtailment	0	0	0
(Increase) decrease in other comprehensive income, settlement	(3)	(2)	(2)
Total (increase) decrease in other comprehensive (Income) Loss	$ 99	$ (6)	$ 212

Postretirement benefits Weighted Average Assumption used to determine the net periodic cost of benefit (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member] \| UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Rate of Compensation Increase		4.00%	4.00%
Expected Long-term Return on Assets	7.00%	7.00%	7.00%
Interest crediting rate, net periodic benefit costs	4.10%	4.10%	4.10%
Pension Plan [Member] \| UNITED STATES \| Interest Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	2.85%	3.94%	3.27%
Pension Plan [Member] \| UNITED STATES \| Service Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate		4.23%	3.62%
Pension Plan [Member] \| Non - U.S.
Defined Benefit Plan Disclosure [Line Items]
Rate of Compensation Increase	3.26%	3.37%	3.46%
Expected Long-term Return on Assets	3.83%	4.40%	4.32%
Pension Plan [Member] \| Non - U.S. \| Interest Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	2.24%	2.88%	2.55%
Pension Plan [Member] \| Non - U.S. \| Service Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	6.04%	4.48%	3.97%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected Long-term Return on Assets	3.00%	3.00%	2.59%
Other Postretirement Benefits Plan [Member] \| Interest Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	2.64%	3.69%	2.62%
Other Postretirement Benefits Plan [Member] \| Service Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.00%	4.04%	2.84%

Postretirement benefits Schedule of Health Care Cost Trend Rates (Details) - Pension Plan [Member]	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
UNITED STATES
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health Care Cost Trend Rate	5.96%	6.32%	6.68%
Ultimate Health Care Cost Trend Rate	4.50%	4.50%	4.50%
Year that Rate Reaches Ultimate Trend Rate	2038	2038	2038
Non - U.S.
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health Care Cost Trend Rate	5.04%	5.24%	6.29%
Ultimate Health Care Cost Trend Rate	4.00%	4.00%	4.50%
Year that Rate Reaches Ultimate Trend Rate	2040	2040	2029

Postretirement benefits Schedule of Allocation of Plan Assets (Details) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

$ 7,945

$ 6,062

Other Postretirement Benefits Plan [Member]

1,747

^[1]

1,537

^[2]

$ 1,247

Defined Benefit Plan, Plan Assets, Amount

120

152

143

Fair Value, Recurring [Member] | Level 1

Fair Value, Recurring [Member] | Level 2

434

412

Fair Value, Recurring [Member] | Level 3

438

377

Other Investments [Member]

10

Investment Funds Limited Partnerships Partially Owned Investment Companies Fair Value [Member]

60

95

UNITED STATES | Pension Plan [Member]

6,770

4,921

Defined benefit plan, fair value of plan assets excluding measured using NAV

3,108

2,873

Defined Benefit Plan, Plan Assets, Amount

3,739

3,301

2,784

UNITED STATES | Pension Plan [Member] | Level 1

14

Defined benefit plan, fair value of plan assets excluding measured using NAV

2,127

1,951

UNITED STATES | Pension Plan [Member] | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

981

922

UNITED STATES | Pension Plan [Member] | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

UNITED STATES | Pension Plan [Member] | Short-term investments

Defined benefit plan, fair value of plan assets excluding measured using NAV

59

55

UNITED STATES | Pension Plan [Member] | Short-term investments | Level 1

Defined benefit plan, fair value of plan assets excluding measured using NAV

59

18

UNITED STATES | Pension Plan [Member] | Short-term investments | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

37

UNITED STATES | Pension Plan [Member] | Short-term investments | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

UNITED STATES | Pension Plan [Member] | US Treasury and Government [Member]

Defined benefit plan, fair value of plan assets excluding measured using NAV

436

600

UNITED STATES | Pension Plan [Member] | US Treasury and Government [Member] | Level 1

Defined benefit plan, fair value of plan assets excluding measured using NAV

250

466

UNITED STATES | Pension Plan [Member] | US Treasury and Government [Member] | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

186

134

UNITED STATES | Pension Plan [Member] | US Treasury and Government [Member] | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

UNITED STATES | Pension Plan [Member] | Debt Security, Government, Non-US [Member]

Defined benefit plan, fair value of plan assets excluding measured using NAV

793

749

UNITED STATES | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 1

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

UNITED STATES | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

793

749

UNITED STATES | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

UNITED STATES | Pension Plan [Member] | States, municipalities, and political subdivisions

Defined benefit plan, fair value of plan assets excluding measured using NAV

2

UNITED STATES | Pension Plan [Member] | States, municipalities, and political subdivisions | Level 1

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

UNITED STATES | Pension Plan [Member] | States, municipalities, and political subdivisions | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

2

UNITED STATES | Pension Plan [Member] | States, municipalities, and political subdivisions | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member]

Defined benefit plan, fair value of plan assets excluding measured using NAV

1,818

1,467

UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 1

Defined benefit plan, fair value of plan assets excluding measured using NAV

1,818

1,467

UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

UNITED STATES | Other Investments [Member] | Pension Plan [Member]

UNITED STATES | Investment Funds Limited Partnerships Partially Owned Investment Companies Fair Value [Member] | Pension Plan [Member]

543

428

Non - U.S. | Pension Plan [Member]

74

Defined benefit plan, fair value of plan assets excluding measured using NAV

1,129

1,030

Defined Benefit Plan, Plan Assets, Amount

1,284

1,141

$ 1,008

Non - U.S. | Pension Plan [Member] | Level 1

Defined benefit plan, fair value of plan assets excluding measured using NAV

132

114

Non - U.S. | Pension Plan [Member] | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

997

916

Non - U.S. | Pension Plan [Member] | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

Non - U.S. | Pension Plan [Member] | Short-term investments

Defined benefit plan, fair value of plan assets excluding measured using NAV

5

2

Non - U.S. | Pension Plan [Member] | Short-term investments | Level 1

Defined benefit plan, fair value of plan assets excluding measured using NAV

5

2

Non - U.S. | Pension Plan [Member] | Short-term investments | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

Non - U.S. | Pension Plan [Member] | Short-term investments | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

Non - U.S. | Pension Plan [Member] | Debt Security, Government, Non-US [Member]

Defined benefit plan, fair value of plan assets excluding measured using NAV

609

598

Non - U.S. | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 1

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

Non - U.S. | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

609

598

Non - U.S. | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

Non - U.S. | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member]

Defined benefit plan, fair value of plan assets excluding measured using NAV

515

430

Non - U.S. | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 1

Defined benefit plan, fair value of plan assets excluding measured using NAV

127

112

Non - U.S. | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 2

Defined benefit plan, fair value of plan assets excluding measured using NAV

388

318

Non - U.S. | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 3

Defined benefit plan, fair value of plan assets excluding measured using NAV

0

Non - U.S. | Other Investments [Member] | Pension Plan [Member]

Non - U.S. | Investment Funds Limited Partnerships Partially Owned Investment Companies Fair Value [Member] | Pension Plan [Member]

147

107

Equity in net income of partially-owned entities

$ 8

$ 4

[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.

Postretirement benefits (Schedule of Expected Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2020 USD ($)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2021	$ 19
2022	20
2023	16
2024	12
2025	7
2026-2030	5
Non - U.S. \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2021	30
2022	28
2023	30
2024	32
2025	32
2026-2030	185
UNITED STATES \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2021	159
2022	166
2023	171
2024	175
2025	180
2026-2030	$ 947

Other (income) expense (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

^[1]

$ 1,019

$ 617

$ 514

Gains (losses) from fair value changes in separate account assets

^[2]

58

44

(38)

Federal excise and capital taxes

(22)

(23)

(12)

Equity in net income of partially-owned entities

(61)

(42)

(30)

Total

994

596

434

Huatai Group [Member]

^[1]

$ 167

$ 74

$ 43

[1]	Equity in net income of partially-owned entities includes $167 million, $74 million, and $43 million attributable to our investments in Huatai (Huatai Group, Huatai P&C, and Huatai Life) for the years ended December 31, 2020, 2019, and 2018, respectively.
[2]	Related to gains (losses) from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP.

Segment Information (Operations By Segment) (Detail) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

$ 33,820

$ 32,275

$ 30,579

33,117

31,290

30,064

21,710

18,730

18,067

784

740

590

6,547

6,153

5,912

2,979

3,030

2,886

1,097

2,637

2,609

3,375

3,426

3,305

(994)

(596)

(434)

Segment Underwriting Income Loss and Net Investment Income Loss

290

305

339

5,176

6,354

6,009

Interest expense

516

552

641

Chubb integration expenses

0

23

59

629

795

695

3,533

4,454

3,962

(Gains) losses from fair value changes in separate account assets

228

585

330

Other (income) expense

(994)

(596)

(434)

^[1]

58

44

(38)

Interest Income (Expense), Net

(498)

(530)

(652)

516

552

641

Segment Reconciling Items [Member]

0

0

1

(8)

(3)

58

44

(38)

0

0

(115)

(86)

(63)

(173)

(130)

(25)

Segment Underwriting Income Loss and Net Investment Income Loss

0

(1)

8

3

Chubb integration expenses

0

0

0

Underwriting Income (Loss)

1

(8)

(3)

(59)

(36)

41

Interest Income (Expense), Net

0

14,474

13,375

12,485

13,964

12,922

12,402

10,129

8,206

8,000

0

1,942

1,831

1,829

1,006

1,028

966

887

1,857

1,607

2,061

2,109

2,061

23

24

3

Segment Underwriting Income Loss and Net Investment Income Loss

0

2,925

3,942

3,665

Segment Insurance North American Personal P&C [Member] [Member]

4,920

4,787

4,674

4,866

4,694

4,593

3,187

3,043

3,229

0

974

948

939

270

286

269

435

417

156

260

258

236

5

3

1

Segment Underwriting Income Loss and Net Investment Income Loss

11

12

13

679

660

378

1,846

1,810

1,577

1,822

1,795

1,569

1,544

1,616

1,114

0

123

84

79

9

6

(9)

146

89

385

30

28

1

2

Segment Underwriting Income Loss and Net Investment Income Loss

27

28

148

90

383

9,335

9,262

8,902

9,285

8,882

8,612

5,255

4,606

4,429

0

2,568

2,501

2,346

1,034

1,033

1,014

428

742

823

534

588

622

13

12

3

Segment Underwriting Income Loss and Net Investment Income Loss

45

41

904

1,273

1,401

731

649

671

698

654

670

435

352

479

0

174

169

162

37

35

41

52

98

(12)

307

279

289

2

1

0

Segment Underwriting Income Loss and Net Investment Income Loss

0

357

376

277

Life Insurance

2,514

2,392

2,270

2,482

2,343

2,218

724

757

766

726

696

628

766

620

557

320

323

310

(54)

(53)

(43)

385

373

341

(74)

(48)

(12)

Segment Underwriting Income Loss and Net Investment Income Loss

4

2

401

366

308

Corporate and Other

0

0

435

158

53

0

0

303

319

295

(738)

(477)

(348)

(87)

(125)

(209)

(791)

(459)

(406)

Segment Underwriting Income Loss and Net Investment Income Loss

203

218

255

(237)

(361)

(406)

Interest expense

516

552

641

Chubb integration expenses

23

59

629

795

695

(1,881)

(2,253)

(2,450)

$ (499)

$ (522)

$ (649)

[1]	Related to gains (losses) from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP.

Segment Information (Net Premiums Earned For Segment By Product) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net premiums earned	$ 33,117	$ 31,290	$ 30,064
North America Commercial P&C Insurance
Segment Reporting Information [Line Items]
Net premiums earned	13,964	12,922	12,402
North America Commercial P&C Insurance \| Property and other short-tail [Member]
Segment Reporting Information [Line Items]
Net premiums earned	2,423	1,987	1,861
North America Commercial P&C Insurance \| Casualty and all other [Member]
Segment Reporting Information [Line Items]
Net premiums earned	10,812	10,136	9,773
North America Commercial P&C Insurance \| Accident and Health [Member]
Segment Reporting Information [Line Items]
Net premiums earned	729	799	768
North American Personal P&C [Member]
Segment Reporting Information [Line Items]
Net premiums earned	4,866	4,694	4,593
North American Personal P&C [Member] \| Automobiles [Member]
Segment Reporting Information [Line Items]
Net premiums earned	822	829	803
North American Personal P&C [Member] \| Personal homeowner [Member]
Segment Reporting Information [Line Items]
Net premiums earned	3,327	3,183	3,127
North American Personal P&C [Member] \| Insurance, Other [Member]
Segment Reporting Information [Line Items]
Net premiums earned	717	682	663
North America Agricultural Insurance
Segment Reporting Information [Line Items]
Net premiums earned	1,822	1,795	1,569
Overseas General Insurance
Segment Reporting Information [Line Items]
Net premiums earned	9,285	8,882	8,612
Overseas General Insurance \| Property and other short-tail [Member]
Segment Reporting Information [Line Items]
Net premiums earned	2,468	2,244	2,134
Overseas General Insurance \| Casualty and all other [Member]
Segment Reporting Information [Line Items]
Net premiums earned	2,738	2,494	2,429
Overseas General Insurance \| Accident and Health [Member]
Segment Reporting Information [Line Items]
Net premiums earned	2,098	2,248	2,265
Overseas General Insurance \| Personal lines [Member]
Segment Reporting Information [Line Items]
Net premiums earned	1,981	1,896	1,784
Segment Global Reinsurance [Member]
Segment Reporting Information [Line Items]
Net premiums earned	698	654	670
Segment Global Reinsurance [Member] \| Property and other short-tail [Member]
Segment Reporting Information [Line Items]
Net premiums earned	104	131	123
Segment Global Reinsurance [Member] \| Casualty and all other [Member]
Segment Reporting Information [Line Items]
Net premiums earned	421	381	377
Segment Global Reinsurance [Member] \| Property catastrophe [Member]
Segment Reporting Information [Line Items]
Net premiums earned	173	142	170
Life Insurance
Segment Reporting Information [Line Items]
Net premiums earned	2,482	2,343	2,218
Life Insurance \| Accident and Health [Member]
Segment Reporting Information [Line Items]
Net premiums earned	1,165	1,242	1,196
Life Insurance \| Life Insurance Product Line [Member]
Segment Reporting Information [Line Items]
Net premiums earned	$ 1,317	$ 1,101	$ 1,022

Segment Information (Net Premiums Earned By Geographic Region) (Details)

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

North America [Member]

Percentage of net premiums earned by geographic region

70.00%

Europe [Member]

Percentage of net premiums earned by geographic region

^[1]

11.00%

Asia Pacific and Far East [Member]

Percentage of net premiums earned by geographic region

12.00%

Latin America [Member]

Percentage of net premiums earned by geographic region

7.00%

[1]	(1) Europe includes Eurasia and Africa regions.

Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income	$ 3,533	$ 4,454	$ 3,962
Weighted-average shares outstanding	451,602,820	455,910,463	463,629,203
Share-based compensation plans	1,838,692	3,004,200	3,173,145
Adjusted weighted-average shares outstanding and assumed conversions	453,441,512	458,914,663	466,802,348
Basic earnings per share	$ 7.82	$ 9.77	$ 8.55
Diluted earnings per share	$ 7.79	$ 9.71	$ 8.49
Potential anti-dilutive share conversions	6,811,966	2,410,337	3,543,188

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

Related party transaction (Details) - USD ($) $ in Millions	12 Months Ended
Related party transaction (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Ceded Premiums Written	$ 7,441	$ 7,849	$ 7,389
Losses and loss expenses	21,710	18,730	18,067
Insurance and reinsurance balances payable	6,708	6,184
Net premiums written	$ 33,820	$ 32,275	30,579
Bermuda \| ABR Reinsurance Capital Holdings Ltd. [Member]
Related Party Transaction [Line Items]
Ownership Percentage	15.60%	12.00%
Starr Technical Risk Agency and Affiliates [Member]
Related Party Transaction [Line Items]
Premiums Written, Gross	$ 507	$ 394	411
Ceded Premiums Written	253	207	188
Paid commissions	97	77	84
Commissions received	59	46	42
Losses and loss expenses	170	185	188
Reinsurance Recoverable on Losses and Loss Expenses	432	440
Insurance and reinsurance balances payable	80	56
Minimum Amount of Program Business to be Written to Earn Profit Sharing	20
ABR Reinsurance Capital Holdings Ltd. [Member]
Related Party Transaction [Line Items]
Ceded Premiums Written	350	321	329
Commissions received	100	92	$ 96
Reinsurance Recoverable on Losses and Loss Expenses	806	674
Insurance and reinsurance balances payable	$ 67	$ 62
Warrants & Rights Outstanding	0.50%

Statutory Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statutory Accounting Practices [Line Items]
Dividends available to be paid	$ 6,400
Approximate increase in statutory capital and surplus resulting from discount of certain A&E liabilities	140	$ 147
Minimum statutory capital and surplus required to satisfy regulatory requirements	29,400	26,700
Statutory Accounting Practices, Permitted Practice, Amount	55	54
PropertyAndCasualtySubsidiaries [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	45,964	43,077
Statutory net income	4,294	6,046	$ 7,521
LifeSubsidiaries [Member] [Member]
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	1,641	1,573
Statutory net income	$ (247)	$ (210)	$ (102)

Information provided in connection with outstanding debt of subsidiaries (Condensed Consolidating Balance Sheet) (Detail) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

$ 118,669

$ 109,234

1,747

^[1]

1,537

^[2]

$ 1,247

Insurance and reinsurance balances receivable, net of valuation allowance - $44 and $44

89

109

93

10,480

10,357

Reinsurance recoverable on losses and loss expenses, net of valuation allowance - $314 and $316

15,592

15,181

206

197

263

306

295

$ 326

21,211

21,359

0

0

22,517

18,663

190,774

176,943

67,811

62,690

62,960

63,179

17,652

16,771

5,713

5,373

0

0

1,405

1,416

0

1,299

14,948

13,559

308

23,496

20,196

131,333

121,612

59,441

55,331

Consolidating Adjustments

190,774

176,943

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

0

(272)

^[1]

0

^[2]

Insurance and reinsurance balances receivable, net of valuation allowance - $44 and $44

0

(3,446)

(2,563)

Reinsurance recoverable on losses and loss expenses, net of valuation allowance - $314 and $316

(9,625)

(9,599)

(93)

(95)

0

0

(111,379)

(102,929)

(3,693)

(4,776)

(1,877)

(1,829)

(130,385)

(121,791)

(9,369)

(9,226)

(1,201)

(1,207)

(93)

(95)

(3,693)

(4,776)

(272)

0

0

0

0

(4,378)

(3,558)

(19,006)

(18,862)

(111,379)

(102,929)

Chubb limited (Parent Guarantor)

(130,385)

(121,791)

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

0

84

^[1]

2

^[2]

$ 1

$ 3

Insurance and reinsurance balances receivable, net of valuation allowance - $44 and $44

0

0

Reinsurance recoverable on losses and loss expenses, net of valuation allowance - $314 and $316

0

0

0

0

56,148

50,853

3,522

4,776

10

12

59,764

55,643

0

0

0

0

0

0

0

0

0

323

312

323

312

59,441

55,331

Chubb INA Holdings Inc. (Subsidiary Issuer)

59,764

55,643

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

197

1,013

1

^[1]

442

^[2]

Insurance and reinsurance balances receivable, net of valuation allowance - $44 and $44

0

0

Reinsurance recoverable on losses and loss expenses, net of valuation allowance - $314 and $316

0

0

0

0

55,231

52,076

0

463

408

55,892

53,939

0

0

0

3,008

4,446

272

0

1,298

14,948

13,559

308

1,418

1,649

19,954

21,260

35,938

32,679

Other Chubb Limited Subsidiaries and Eliminations

55,892

53,939

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

118,472

108,221

1,934

^[1]

1,093

^[2]

Insurance and reinsurance balances receivable, net of valuation allowance - $44 and $44

89

109

13,926

12,920

Reinsurance recoverable on losses and loss expenses, net of valuation allowance - $314 and $316

25,217

24,780

299

292

263

306

21,211

21,359

0

171

0

23,921

20,072

205,503

189,152

77,180

71,916

18,853

17,978

5,806

5,468

685

330

0

1,405

1,416

1

0

0

26,133

21,793

130,062

118,902

75,441

70,250

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

$ 205,503

$ 189,152

[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.

Information provided in connection with outstanding debt of subsidiaries (Condensed Consolidating Statement Of Operations and Comprehensive Income) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Net premiums written	$ 33,820	$ 32,275	$ 30,579
Net premiums earned	33,117	31,290	30,064
Net Investment Income	3,375	3,426	3,305
Equity in earnings of subsidiaries	0	0	0
Realized Investment Gains (Losses)	(498)	(530)	(652)
Losses and loss expenses	21,710	18,730	18,067
Policy benefits	784	740	590
Policy acquisition costs and administrative expenses	9,526	9,183	8,798
Interest (income) expense	516	552	641
Other (Income) Expense	(994)	(596)	(434)
Amortization of Purchased Intangibles	290	305	339
Chubb integration expenses	0	23	59
Income tax expense (benefit)	629	795	695
Net income	3,533	4,454	3,962
Comprehensive income	5,783	7,521	1,242
Chubb limited (Parent Guarantor)
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Net premiums written	0	0	0
Net premiums earned	0	0	0
Net Investment Income	(1)	1	6
Equity in earnings of subsidiaries	3,457	4,307	3,753
Realized Investment Gains (Losses)	20	(17)	0
Losses and loss expenses	0	0	0
Policy benefits	0	0	0
Policy acquisition costs and administrative expenses	94	92	87
Interest (income) expense	(136)	(243)	(299)
Other (Income) Expense	(39)	(27)	(24)
Amortization of Purchased Intangibles	0	0	0
Chubb integration expenses	0	1	14
Income tax expense (benefit)	24	14	19
Net income	3,533	4,454	3,962
Comprehensive income	5,783	7,521	1,242
Chubb INA Holdings Inc. (Subsidiary Issuer)
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Net premiums written	0	0	0
Net premiums earned	0	0	0
Net Investment Income	6	(15)	13
Equity in earnings of subsidiaries	2,052	3,022	2,578
Realized Investment Gains (Losses)	(397)	(31)	117
Losses and loss expenses	0	0	0
Policy benefits	0	0	0
Policy acquisition costs and administrative expenses	(130)	(26)	(58)
Interest (income) expense	596	705	806
Other (Income) Expense	(24)	6	26
Amortization of Purchased Intangibles	0	0	0
Chubb integration expenses		2	1
Income tax expense (benefit)	(181)	(175)	(148)
Net income	1,400	2,464	2,081
Comprehensive income	3,236	4,988	(27)
Other Chubb Limited Subsidiaries and Eliminations
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Net premiums written	33,820	32,275	30,579
Net premiums earned	33,117	31,290	30,064
Net Investment Income	3,370	3,440	3,286
Equity in earnings of subsidiaries	0	0	0
Realized Investment Gains (Losses)	(121)	(482)	(769)
Losses and loss expenses	21,710	18,730	18,067
Policy benefits	784	740	590
Policy acquisition costs and administrative expenses	9,562	9,117	8,769
Interest (income) expense	56	90	134
Other (Income) Expense	(931)	(575)	(436)
Amortization of Purchased Intangibles	290	305	339
Chubb integration expenses		20	44
Income tax expense (benefit)	786	956	824
Net income	4,109	4,865	4,250
Comprehensive income	6,512	7,922	1,808
Consolidating Adjustments
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Net premiums written	0	0	0
Net premiums earned	0	0	0
Net Investment Income	0	0	0
Equity in earnings of subsidiaries	(5,509)	(7,329)	(6,331)
Realized Investment Gains (Losses)	0	0	0
Losses and loss expenses	0	0	0
Policy benefits	0	0	0
Policy acquisition costs and administrative expenses	0	0	0
Interest (income) expense	0	0	0
Other (Income) Expense	0	0	0
Amortization of Purchased Intangibles	0	0	0
Chubb integration expenses		0	0
Income tax expense (benefit)	0	0	0
Net income	(5,509)	(7,329)	(6,331)
Comprehensive income	$ (9,748)	$ (12,910)	$ (1,781)

Information provided in connection with outstanding debt of subsidiaries (Condensed Consolidating Statement Of Cash Flows) (Detail) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Payments To Acquire Available For Sale Securities Debt Condensed

$ 9,785

$ 6,342

$ 5,480

(26,298)

(25,846)

(24,735)

(202)

(229)

(456)

Proceeds From Sale Of Available For Sale Securities Debt Condensed

(6,419)

(531)

(207)

11,377

13,116

14,030

Maturities and redemptions of fixed maturities available for sale

3,880

611

315

12,450

9,039

7,352

Maturities and redemptions of fixed maturities held to maturity

995

946

1,124

(81)

(1,117)

516

(113)

(703)

16

(1,924)

(1,315)

(1,337)

Payment, including deposit, for Huatai Group Interest

907

1,390

980

(1,623)

(580)

Payments to Acquire Businesses, Net of Cash Acquired

0

(29)

0

0

Net Cash Provided by (Used in) Investing Activities

(470)

(657)

(533)

(7,521)

(5,905)

(2,935)

(1,388)

(1,354)

(1,337)

(523)

(1,530)

(1,044)

Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase

988

2,828

2,171

2,354

2,817

2,029

Payments for Securities Purchased under Agreements to Resell

(1,301)

(510)

(2,001)

(2,354)

(2,817)

(2,019)

145

204

115

0

0

Net proceeds from (Repayments to) affiliated notional cash pooling program

0

0

^[1]

0

470

514

453

(386)

(303)

(358)

Net cash flows (used for) from financing activities

(87)

0

(2,082)

(151)

(1,991)

Effect of foreign currency rate changes on cash and restricted cash

8

20

(65)

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect

190

306

489

1,646

^[1],[2]

1,340

^[2],[3]

851

^[3]

Cash Acquired from Acquisition

^[2]

1,836

1,646

^[1]

1,340

^[3]

0

45

0

Parent Company Only

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

Payments To Acquire Available For Sale Securities Debt Condensed

1,933

412

256

0

0

Proceeds From Sale Of Available For Sale Securities Debt Condensed

0

0

Maturities and redemptions of fixed maturities available for sale

0

0

Maturities and redemptions of fixed maturities held to maturity

0

0

0

0

Payment, including deposit, for Huatai Group Interest

0

0

Payments to Acquire Businesses, Net of Cash Acquired

0

(1,200)

(1,000)

(1,475)

Net Cash Provided by (Used in) Investing Activities

2

0

(1,202)

(1,000)

(1,475)

(1,388)

(1,354)

(1,337)

(523)

(327)

0

Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase

0

0

Payments for Securities Purchased under Agreements to Resell

0

0

0

1,265

2,301

2,519

0

Net proceeds from (Repayments to) affiliated notional cash pooling program

0

^[4]

0

(35)

35

0

0

Net cash flows (used for) from financing activities

0

(646)

585

1,217

Effect of foreign currency rate changes on cash and restricted cash

(3)

4

0

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect

82

1

(2)

2

^[1],[2]

1

^[2],[3]

3

^[3]

Chubb INA Holdings Inc. (Subsidiary Issuer)

^[2]

84

2

^[1]

1

^[3]

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

Payments To Acquire Available For Sale Securities Debt Condensed

274

2,926

4,654

(49)

(21)

(38)

0

Proceeds From Sale Of Available For Sale Securities Debt Condensed

0

9

1

11

Maturities and redemptions of fixed maturities available for sale

0

50

41

17

Maturities and redemptions of fixed maturities held to maturity

0

772

(808)

3

55

(74)

(7)

0

Payment, including deposit, for Huatai Group Interest

0

0

Payments to Acquire Businesses, Net of Cash Acquired

0

(72)

(110)

(3,550)

Net Cash Provided by (Used in) Investing Activities

4

(4)

(18)

769

(975)

(3,582)

0

0

Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase

988

2,828

2,171

0

Payments for Securities Purchased under Agreements to Resell

(1,301)

(500)

(2,000)

0

0

(1,438)

(3,223)

(1,744)

0

Net proceeds from (Repayments to) affiliated notional cash pooling program

0

272

(617)

502

0

0

Net cash flows (used for) from financing activities

0

(1,479)

(1,512)

(1,071)

Effect of foreign currency rate changes on cash and restricted cash

(5)

1

0

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect

(441)

440

1

442

^[1],[2]

2

^[2],[3]

1

^[3]

Other Chubb Limited Subsidiaries and Eliminations

^[2]

1

442

^[1]

2

^[3]

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

Payments To Acquire Available For Sale Securities Debt Condensed

10,788

6,878

5,878

(26,249)

(25,825)

(24,697)

(202)

(229)

(456)

Proceeds From Sale Of Available For Sale Securities Debt Condensed

(6,419)

(531)

(207)

11,368

13,115

14,019

Maturities and redemptions of fixed maturities available for sale

3,880

611

315

12,400

8,998

7,335

Maturities and redemptions of fixed maturities held to maturity

995

946

1,124

(853)

(309)

513

(168)

(629)

23

(1,924)

(1,315)

(1,337)

Payment, including deposit, for Huatai Group Interest

907

1,390

980

(1,623)

(580)

Payments to Acquire Businesses, Net of Cash Acquired

(29)

0

Net Cash Provided by (Used in) Investing Activities

(472)

(653)

(515)

(8,360)

(5,040)

(2,903)

0

0

(1,203)

(1,044)

Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase

0

2,354

2,817

2,029

Payments for Securities Purchased under Agreements to Resell

0

(10)

(1)

(2,354)

(2,817)

(2,019)

145

204

115

173

922

(775)

(3,210)

(3,874)

(5,308)

Net proceeds from (Repayments to) affiliated notional cash pooling program

1,272

1,110

5,025

0

470

514

453

(386)

(303)

(358)

Net cash flows (used for) from financing activities

(87)

(1,623)

(2,640)

(1,883)

Effect of foreign currency rate changes on cash and restricted cash

16

15

(65)

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect

821

(787)

1,027

1,202

^[1],[2]

1,989

^[3]

962

^[3]

Consolidating Adjustments

2,023

^[2]

1,202

^[1],[2]

1,989

^[3]

Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]

Payments To Acquire Available For Sale Securities Debt Condensed

(3,210)

(3,874)

(5,308)

0

0

Proceeds From Sale Of Available For Sale Securities Debt Condensed

0

0

Maturities and redemptions of fixed maturities available for sale

0

0

Maturities and redemptions of fixed maturities held to maturity

0

0

0

0

Payment, including deposit, for Huatai Group Interest

0

0

Payments to Acquire Businesses, Net of Cash Acquired

0

1,272

1,110

5,025

Net Cash Provided by (Used in) Investing Activities

0

1,272

1,110

5,025

0

0

Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase

0

0

Payments for Securities Purchased under Agreements to Resell

0

0

0

0

3,210

3,874

5,308

Net proceeds from (Repayments to) affiliated notional cash pooling program

(1,272)

(1,110)

(5,025)

(272)

652

^[1]

(537)

0

0

Net cash flows (used for) from financing activities

0

1,666

3,416

(254)

Effect of foreign currency rate changes on cash and restricted cash

0

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect

(272)

652

(537)

0

^[1],[2]

(652)

^[2],[3]

(115)

^[3]

Investments in subsidiaries and affiliates on equity basis

^[2]

$ (272)

$ 0

^[1]

$ (652)

^[3]

[1]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[3]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018 and 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[4]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.

Schedule I (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Other Investments	$ 7,945	$ 6,062
Cost or Amortized Cost	113,023
Fair Value	119,407
Amount at Which Shown in the Balance Sheet	118,550
All Related Party [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Other Investments	119
Fixed maturities available for sale
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	85,168
Fair Value	90,699
Amount at Which Shown in the Balance Sheet	90,699
Fixed maturities available for sale \| U.S. Treasury and agency
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	2,471
Fair Value	2,670
Amount at Which Shown in the Balance Sheet	2,670
Fixed maturities available for sale \| Foreign
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	24,588
Fair Value	26,354
Amount at Which Shown in the Balance Sheet	26,354
Fixed maturities available for sale \| Corporate securities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	34,081
Fair Value	36,331
Amount at Which Shown in the Balance Sheet	36,331
Fixed maturities available for sale \| Mortgage-backed securities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	17,456
Fair Value	18,470
Amount at Which Shown in the Balance Sheet	18,470
Fixed maturities available for sale \| States, municipalities, and political subdivisions
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	6,572
Fair Value	6,874
Amount at Which Shown in the Balance Sheet	6,874
Fixed maturities held to maturity
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	11,653
Fair Value	12,510
Amount at Which Shown in the Balance Sheet	11,653
Fixed maturities held to maturity \| U.S. Treasury and agency
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	1,392
Fair Value	1,452
Amount at Which Shown in the Balance Sheet	1,392
Fixed maturities held to maturity \| Foreign
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	1,288
Fair Value	1,405
Amount at Which Shown in the Balance Sheet	1,288
Fixed maturities held to maturity \| Corporate securities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	2,150
Fair Value	2,438
Amount at Which Shown in the Balance Sheet	2,150
Fixed maturities held to maturity \| Mortgage-backed securities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	1,999
Fair Value	2,146
Amount at Which Shown in the Balance Sheet	1,999
Fixed maturities held to maturity \| States, municipalities, and political subdivisions
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	4,824
Fair Value	5,069
Amount at Which Shown in the Balance Sheet	4,824
Industrial, miscellaneous, and all others
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	4,027
Fair Value	4,027
Amount at Which Shown in the Balance Sheet	4,027
Short-term investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	4,349
Fair Value	4,345
Amount at Which Shown in the Balance Sheet	4,345
Other investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost or Amortized Cost	7,826
Fair Value	7,826
Amount at Which Shown in the Balance Sheet	$ 7,826

Schedule II (BALANCE SHEETS - Parent Company Only) (Details) - USD ($)
$ in Millions

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Assets

$ 0

1,747

^[1]

1,537

^[2]

$ 1,247

0

8,822

7,581

Accounts payable, accrued expenses, and other liabilities

190,774

176,943

Liabilities

14,052

12,214

Stockholders' Equity Attributable to Parent [Abstract]

131,333

121,612

Common Shares

11,064

11,121

Common Shares in treasury (26,872,639 and 27,812,297 shares)

(3,644)

(3,754)

Retained earnings

39,337

36,142

Accumulated other comprehensive income

2,869

619

59,441

55,331

50,312

Investments in subsidiaries and affiliates on equity basis

190,774

176,943

Parent Company Only

Assets

56,148

50,853

Total investments

56,148

50,853

84

^[1]

2

^[2]

$ 1

$ 3

3,522

4,776

10

12

Accounts payable, accrued expenses, and other liabilities

59,764

55,643

Liabilities

323

312

Stockholders' Equity Attributable to Parent [Abstract]

323

312

Common Shares

11,064

11,121

Common Shares in treasury (26,872,639 and 27,812,297 shares)

(3,644)

(3,754)

Additional paid-in capital

9,815

11,203

Retained earnings

39,337

36,142

Accumulated other comprehensive income

2,869

619

59,441

55,331

Condensed Financial Statements, Captions [Line Items]

$ 59,764

$ 55,643

[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.

Schedule II Schedule II (STATEMENTS OF OPERATIONS - Parent Company Only) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Equity in net income of subsidiaries and affiliates

^[1]

$ 1,019

$ 617

$ 514

Total revenues

35,994

34,186

32,717

Administrative and other (income) expense

2,979

3,030

2,886

Business Combination, Integration Related Costs

0

23

59

629

795

695

Total expenses

31,832

28,937

28,060

Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest

3,533

4,454

3,962

5,783

7,521

1,242

Chubb limited (Parent Guarantor)

Condensed Financial Statements, Captions [Line Items]

Investment income, including intercompany interest income

155

227

305

Equity in net income of subsidiaries and affiliates

3,457

4,307

3,753

Total revenues

3,612

4,534

4,058

Administrative and other (income) expense

55

65

63

Business Combination, Integration Related Costs

0

1

14

24

14

19

Total expenses

79

80

96

Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest

3,533

4,454

3,962

$ 5,783

$ 7,521

$ 1,242

[1]	Equity in net income of partially-owned entities includes $167 million, $74 million, and $43 million attributable to our investments in Huatai (Huatai Group, Huatai P&C, and Huatai Life) for the years ended December 31, 2020, 2019, and 2018, respectively.

Schedule II (STATEMENTS OF CASH FLOWS - Parent Company Only) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Condensed Financial Statements, Captions [Line Items]

$ 9,785

$ 6,342

$ 5,480

0

(1,388)

(1,354)

(1,337)

Net proceeds from (payments to) affiliated notional cash pooling programs

(523)

(1,530)

(1,044)

0

^[1]

0

Net cash flows (used for) from financing activities

(2,082)

(151)

(1,991)

Effect of foreign currency rate changes on cash and restricted cash

8

20

(65)

Cash and restricted cash – beginning of year

1,537

^[2]

1,247

Cash and restricted cash – end of year

1,747

^[3]

1,537

^[2]

1,247

Payments for (Proceeds from) Other Investing Activities

470

657

533

Chubb limited (Parent Guarantor)

Condensed Financial Statements, Captions [Line Items]

1,933

412

256

Net cash flows used for investing activities

(1,200)

(1,000)

(1,475)

(1,202)

(1,000)

(1,475)

(1,388)

(1,354)

(1,337)

Payments To From Affiliates

(523)

(327)

0

1,265

2,301

2,519

Net proceeds from (payments to) affiliated notional cash pooling programs

^[4]

0

(35)

35

Net cash flows (used for) from financing activities

(646)

585

1,217

Effect of foreign currency rate changes on cash and restricted cash

(3)

4

0

Net increase (decrease) in cash and restricted cash

82

1

(2)

Cash and restricted cash – beginning of year

2

^[2]

1

3

Cash and restricted cash – end of year

84

^[3]

2

^[2]

1

Cash dividend paid by Affiliates

^[5]

2,000

200

75

Payments for (Proceeds from) Other Investing Activities

$ (2)

$ 0

[1]	Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.
[3]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[4]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.
[5]	Includes cash dividends received from subsidiaries of $2.0 billion, $200 million, and $75 million in 2020, 2019, and 2018, respectively.

Schedule IV (SUPPLEMENTAL INFORMATION CONCERNING REINSURANCE) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Amount	$ 37,037	$ 35,876	$ 34,108
Ceded To Other Companies	7,243	7,693	7,219
Assumed From Other Companies	3,323	3,107	3,175
Net Amount	$ 33,117	$ 31,290	$ 30,064
Percentage of Amount Assumed to Net	10.00%	10.00%	11.00%
Property and Casualty [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Amount	$ 31,546	$ 30,339	$ 28,793
Ceded To Other Companies	6,782	7,236	6,792
Assumed From Other Companies	3,044	2,797	2,812
Net Amount	$ 27,808	$ 25,900	$ 24,813
Percentage of Amount Assumed to Net	11.00%	11.00%	11.00%
Accident and Health [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Amount	$ 4,249	$ 4,546	$ 4,409
Ceded To Other Companies	368	376	342
Assumed From Other Companies	111	119	162
Net Amount	$ 3,992	$ 4,289	$ 4,229
Percentage of Amount Assumed to Net	3.00%	3.00%	4.00%
Life [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Amount	$ 1,242	$ 991	$ 906
Ceded To Other Companies	93	81	85
Assumed From Other Companies	168	191	201
Net Amount	$ 1,317	$ 1,101	$ 1,022
Percentage of Amount Assumed to Net	13.00%	17.00%	20.00%

Schedule VI (SUPPLEMENTARY INFORMATION CONCERNING PROPERTY AND CASUALTY OPERATIONS) (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]

Deferred Policy Acquisition Costs

$ 4,244

$ 4,161

$ 3,926

Net Reserves for Unpaid Losses

53,164

48,509

48,271

Unearned Premiums

17,652

16,771

15,532

Net Premiums Earned

31,800

30,189

29,042