1,000

^[1]

728

^[2]

^[1]

101

123

Accrued investment income

2,355

1,737

870

909

10,341

9,334

14,792

15,034

Deferred policy acquisition costs

204

184

4,916

4,723

Prepaid reinsurance premiums

311

326

Goodwill

15,476

15,541

Other intangible assets

6,283

6,513

2,686

2,529

Investments in partially-owned insurance companies

675

662

6,338

6,235

167,534

167,022

Liabilities

62,778

63,179

15,748

15,216

Insurance and reinsurance balances payable

5,470

5,321

6,448

5,868

Securities lending payable

2,355

1,737

Accounts payable, accrued expenses, and other liabilities

8,933

9,545

Deferred tax liabilities

326

699

1,413

1,408

600

1,013

12,184

11,556

308

Commitments and contingencies

116,563

115,850

Shareholders’ equity

Common Shares (CHF 24.15 par value; 479,783,864 shares issued; 463,502,164 and 463,833,179 shares outstanding)

11,121

Common Shares in treasury (16,281,700 and 15,950,685 shares)

(2,040)

(1,944)

Additional Paid in Capital, Common Stock

13,150

13,978

Retained earnings

30,260

27,474

Accumulated other comprehensive income (loss) (AOCI)

(1,520)

543

Total shareholders’ equity

50,971

51,172

Organization, Consolidation and Presentation of Financial Statements [Abstract]

$ 167,534

$ 167,022

[1]

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 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. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Consolidated Balance Sheets (Parenthetical) $ in Millions	Jun. 30, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares
Statement of Financial Position [Abstract]
Available for sale, at amortized cost	$ 78,546	$ 77,835
Fixed maturities available for sale, hybrid financial instruments	9	5
Held to maturity, at Fair Value	13,665	14,474
Equity securities, at cost	933	737
Other investments, cost	$ 5,259	$ 4,417
Common Shares, shares issued \| shares	479,783,864	479,783,864
Common Shares, shares outstanding \| shares	463,502,164	463,833,179
Common Shares in treasury, shares \| shares	16,281,700	15,950,685

Consolidated Statements Of Operations and Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Net premiums written	$ 8,015	$ 7,581	$ 15,119	$ 14,291
Change In Unearned Premium Net	(351)	(344)	(428)	(282)
Net premiums earned	7,664	7,237	14,691	14,009
Net investment income	828	770	1,634	1,515
Net Realized Gains Losses [Abstract]
Other-than-temporary impairment (OTTI) losses gross	(4)	(9)	(5)	(28)
Portion of OTTI losses recognized in other comprehensive income (OCI)	0	1	0	1
Net OTTI losses recognized in income	(4)	(8)	(5)	(27)
Net realized gains (losses) excluding OTTI losses	22	109	21	121
Total net realized gains (losses) (includes $(81), $25, $(104) and $17 reclassified from AOCI)	18	101	16	94
Total revenues	8,510	8,108	16,341	15,618
Expenses
Losses and loss expenses	4,487	4,146	8,589	7,935
Policy benefits	150	163	301	331
Policy acquisition costs	1,464	1,449	2,928	2,846
Administrative expenses	747	706	1,439	1,382
Interest expense	167	147	324	301
Other (income) expense	(115)	(145)	(162)	(215)
Amortization of purchased intangibles	85	65	170	129
Chubb integration expenses	13	72	23	183
Total expenses	6,998	6,603	13,612	12,892
Income before income tax	1,512	1,505	2,729	2,726
Income tax expense (benefit) (includes $(12), $9, $(15) and $3 on reclassified unrealized gains and losses)	218	200	353	328
Net income	1,294	1,305	2,376	2,398
Other comprehensive income (loss)
Unrealized appreciation (depreciation)	(578)	459	(1,812)	766
Reclassification adjustment for net realized (gains) losses included in net income	81	(25)	104	(17)
Unrealized appreciation (Depreciation) after reclassification adjustment	(497)	434	(1,708)	749
Change in:
Cumulative foreign currency translation adjustment	(574)	102	(177)	236
Postretirement benefit liability adjustment	(17)	(35)	(40)	(55)
Other comprehensive income (loss), before income tax	(1,088)	501	(1,925)	930
Income tax (expense) benefit related to OCI items	71	(131)	279	(246)
Other comprehensive income (loss)	(1,017)	370	(1,646)	684
Comprehensive income	$ 277	$ 1,675	$ 730	$ 3,082
Earnings per share
Basic earnings per share	$ 2.78	$ 2.79	$ 5.10	$ 5.12
Diluted earnings per share	$ 2.76	$ 2.77	$ 5.07	$ 5.08

Consolidated Statements Of Operations and Comprehensive Income Consolidated Statements of Operations and Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Total net realized gains (losses) reclassified from AOCI	$ (81)	$ 25	$ (104)	$ 17
Income tax expense on reclassified unrealized gains and loses	$ (12)	$ 9	$ (15)	$ 3

Consolidated Statements Of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Common shares in treasury [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]	Cumulative Foreign Currency Translation Adjustment [Member]	Postretirement Benefit Liability Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance - beginning of period at Dec. 31, 2016		$ 11,121	$ (1,480)	$ 15,335	$ 23,613	$ 1,058	$ (1,663)	$ 291
Common Shares repurchased			(475)
Net shares redeemed under employee share-based compensation plans			280	(275)
Exercise of stock options				(38)
Share-based compensation expense				156
Net income	$ 2,398				2,398
Funding of dividends declared to Retained earnings				(656)
Funding of dividends declared from Additional paid-in capital					656
Dividends declared on Common Shares					(656)
Change in period, before reclassification from AOCI, net of income tax benefit (expense) of $300 and $(259)						507
Amounts reclassified from AOCI, net of income tax benefit (expense) of $(15) and $3						(14)
Change in period, net of income tax benefit (expense) of $285 and $(256)						493
Change in period, net of income tax expense of $(15) and $(7)							229
Change in period, net of income tax benefit of $9 and $17								(38)
Balance - end of period at Jun. 30, 2017	50,349		(1,675)	14,522	26,011	1,551	(1,434)	253	$ 370
Cumulative effect of adoption of accounting guidance (refer to Note 1)					410	(417)
Balance - beginning of period (Scenario, Previously Reported [Member]) at Dec. 31, 2017					27,474	1,450
Balance - beginning of period at Dec. 31, 2017	51,172	$ 11,121	(1,944)	13,978	27,884	1,033	(1,187)	280
Common Shares repurchased			(324)
Net shares redeemed under employee share-based compensation plans			228	(261)
Exercise of stock options				(19)
Share-based compensation expense				123
Net income	2,376				2,376
Funding of dividends declared to Retained earnings				(671)
Funding of dividends declared from Additional paid-in capital					671
Dividends declared on Common Shares					(671)
Change in period, before reclassification from AOCI, net of income tax benefit (expense) of $300 and $(259)						(1,512)
Amounts reclassified from AOCI, net of income tax benefit (expense) of $(15) and $3						89
Change in period, net of income tax benefit (expense) of $285 and $(256)						(1,423)
Change in period, net of income tax expense of $(15) and $(7)							(192)
Change in period, net of income tax benefit of $9 and $17								(31)
Balance - end of period at Jun. 30, 2018	$ 50,971		$ (2,040)	$ 13,150	$ 30,260	$ (390)	$ (1,379)	$ 249	$ (1,520)

Consolidated Statements Of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Statement Consolidated Statements Of Shareholders Equity [Abstract]
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax	$ 300	$ (259)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	(15)	3
Net unrealized appreciation on investments, Change in period, income tax (expense) benefit	285	(256)
Cumulative translation adjustment, Change in period, income tax(expense) benefit	(15)	(7)
Pension liability adjustment, Change in period, income tax (expense) benefit	$ 9	$ 17

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities
Net income	$ 2,376	$ 2,398
Adjustments to reconcile net income to net cash flows from operating activities
Net realized (gains) losses	(16)	(94)
Amortization of premiums/discounts on fixed maturities	311	353
Amortization of purchased intangibles	170	129
Deferred income taxes	(71)	(112)
Unpaid losses and loss expenses	(267)	(411)
Unearned premiums	635	386
Future policy benefits	144	134
Insurance and reinsurance balances payable	675	278
Accounts payable, accrued expenses, and other liabilities	(489)	(603)
Income taxes payable	224	(103)
Insurance and reinsurance balances receivable	(1,129)	(575)
Reinsurance recoverable on losses and loss expenses	200	312
Reinsurance recoverable on policy benefits	(22)	(15)
Deferred policy acquisition costs	(213)	(179)
Prepaid reinsurance premiums	(205)	(139)
Other	(126)	(119)
Net cash flows from operating activities	2,197	1,640
Cash flows from investing activities
Purchases of fixed maturities available for sale	(12,297)	(12,260)
Purchases of fixed maturities held to maturity	(337)	(212)
Purchases of equity securities	(85)	(82)
Sales of fixed maturities available for sale	6,858	6,873
Sales of equity securities	83	104
Maturities and redemptions of fixed maturities available for sale	3,920	5,169
Maturities and redemptions of fixed maturities held to maturity	732	408
Net change in short-term investments	401	354
Net derivative instruments settlements	5	(129)
Private equity contribution	(813)	(345)
Private equity distribution	413	487
Other	(140)	(244)
Net cash flows from (used for) investing activities	(1,260)	123
Cash flows from financing activities
Dividends paid on Common Shares	(661)	(646)
Common Shares repurchased	(347)	(475)
Proceeds from issuance of long-term debt	(1,900)	(500)
Proceeds from issuance of repurchase agreements	1,014	1,343
Proceeds from Issuance of Long-term Debt	2,171	0
Repayment of repurchase agreements	(1,009)	(1,338)
Proceeds from share-based compensation plans	60	89
Policyholder contract deposits	192	209
Policyholder contract withdrawals	(169)	(125)
Net cash flows used for financing activities	(649)	(1,443)
Effect of foreign currency rate changes on cash and restricted cash	(38)	11
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	250	331
Cash and Restricted Cash - Beginning of year	851	1,088
Cash and Restricted Cash - end of Year	1,101	1,419
Supplemental cash flow information
Taxes paid	223	510
Interest paid	$ 332	$ 327

General

6 Months Ended

Jun. 30, 2018

General

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. Chubb operates 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 10 for additional information.

The interim unaudited 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 (consisting of normally recurring accruals) 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 results of operations and cash flows for any interim period are not necessarily indicative of the results for the full year. These consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in our 2017 Form 10-K.

b) Restricted cash

Effective January 1, 2018, we retrospectively adopted guidance on "Restricted Cash" that clarified the presentation of restricted cash on the consolidated statement of cash flows. As a result, we revised the statement of cash flows for the six months ended June 30, 2017 to include restricted cash in the beginning and ending cash balances. In addition, we reclassified $123 million of Restricted cash from Other assets to a separate line in the balance sheet as of December 31, 2017.

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:



	June 30		December 31
(in millions of U.S. dollars)	2018		2017
Cash	$	1,000	$	728
Restricted cash	101		123
Total cash and restricted cash shown in the consolidated statements of cash flows	$	1,101	$	851

c) Goodwill

During the six months ended June 30, 2018, Goodwill decreased $65 million, primarily reflecting the impact of foreign exchange.

d) Accounting guidance adopted in 2018

Revenue from Contracts with Customers

In May 2014, the FASB issued an accounting standard that supersedes most existing revenue recognition guidance. The standard excludes from its scope the accounting for insurance contracts, leases, financial instruments, and certain other agreements that are governed under other GAAP guidance, but could affect the revenue recognition for certain of our claims management and risk control services. The updated guidance requires an entity to recognize revenue as performance obligations are met, in order to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration the entity is entitled to receive for those goods or services. This guidance was effective for us on January 1, 2018. The adoption of this guidance did not have a material impact on our financial condition or results of operations given that the majority of our business is outside the scope of this guidance.

Financial Instruments – Recognition and Measurement of Financial Assets and Financial Liabilities

Effective January 2018, we adopted new accounting guidance on "Recognition and Measurement of Financial Assets and Financial Liabilities" on a modified-retrospective basis. The guidance requires equity investments, other than those accounted for under the equity method of accounting, to be measured at fair value with changes in fair value recognized through net income. The guidance impacts our public equities and cost-method private equities. As a result, we recorded a cumulative-effect adjustment to increase beginning Retained earnings by $417 million after tax ($454 million pre-tax), representing the unrealized appreciation on our equity investments with an offsetting adjustment to decrease Accumulated other comprehensive income. All subsequent changes in fair value of our equity investments are recognized within realized gains (losses) on the consolidated statement of operations. Prior period amounts have not been adjusted and continue to be reported in accordance with the previous accounting guidance.

Income Taxes

Effective January 2018, we adopted new accounting guidance on “Intra-Entity Transfers of Assets Other Than Inventory” on a modified-retrospective basis. Under the new guidance, we will no longer defer taxes on intra-company asset transfers and will recognize any related income tax expense (benefit) immediately through the consolidated statement of operations. As a result, we recorded a cumulative-effect adjustment to decrease beginning Retained earnings by $7 million representing the removal of the deferred tax asset for previous intra-company asset transfer transactions not yet recognized through earnings.

Income Tax Accounting Implications of the Tax Cuts and Jobs Act

The Tax Cuts and Jobs Act (2017 Tax Act) was signed into legislation in December 2017. The Securities and Exchange Commission issued Staff Accounting Bulletin No. 118 (SAB 118), Income Tax Accounting Implications of the Tax Cuts and Jobs Act, which provides guidance for the application of the 2017 Tax Act. The income tax guidance allows for the transition impact of the 2017 Tax Act to be recorded as 1) complete with all accounting implications identified, 2) provisional based on a reasonable estimate, or 3) not recorded as no reasonable estimate was determinable.

In December 2017, we recorded a $450 million income tax benefit which was our estimate of the tax effects of the 2017 Tax Act. This amount was recorded as provisional under SAB 118. There were no changes determined to this estimate for the current period as we continue to analyze the impact of the 2017 Tax Act. We will continue to monitor this area as new regulations and interpretive guidance are released and will update as appropriate.

Refer to the 2017 Form 10-K for information on other accounting guidance not yet adopted.

Investments

6 Months Ended

Jun. 30, 2018

Investments, Debt and Equity Securities [Abstract]

a) Fixed maturities



June 30, 2018	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
(in millions of U.S. dollars)	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
Available for sale
U.S. Treasury and agency	$	3,827	$	18	$	(81	)	$	3,764	$	—
Foreign	21,884		421		(294		)	22,011		—
Corporate securities	24,665		235		(415		)	24,485		(4		)
Mortgage-backed securities	15,853		40		(410		)	15,483		(1		)
States, municipalities, and political subdivisions	12,317		55		(152		)	12,220		—
	$	78,546	$	769	$	(1,352	)	$	77,963	$	(5	)
Held to maturity
U.S. Treasury and agency	$	1,143	$	9	$	(19	)	$	1,133	$	—
Foreign	1,678		14		(17		)	1,675		—
Corporate securities	2,736		14		(85		)	2,665		—
Mortgage-backed securities	2,640		7		(62		)	2,585		—
States, municipalities, and political subdivisions	5,663		16		(72		)	5,607		—
	$	13,860	$	60	$	(255	)	$	13,665	$	—



December 31, 2017	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
(in millions of U.S. dollars)	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
Available for sale
U.S. Treasury and agency	$	3,701	$	32	$	(35	)	$	3,698	$	—
Foreign	20,514		622		(106		)	21,030		(1		)
Corporate securities	23,453		638		(95		)	23,996		(4		)
Mortgage-backed securities	15,279		111		(100		)	15,290		(1		)
States, municipalities, and political subdivisions	14,888		125		(88		)	14,925		—
	$	77,835	$	1,528	$	(424	)	$	78,939	$	(6	)
Held to maturity
U.S. Treasury and agency	$	908	$	12	$	(5	)	$	915	$	—
Foreign	1,738		27		(8		)	1,757		—
Corporate securities	3,159		67		(7		)	3,219		—
Mortgage-backed securities	2,724		23		(5		)	2,742		—
States, municipalities, and political subdivisions	5,806		50		(15		)	5,841		—
	$	14,335	$	179	$	(40	)	$	14,474	$	—

As discussed in Note 2 b), if a credit loss is incurred on an impaired fixed maturity, an OTTI is considered to have occurred and the portion of the impairment not related to credit losses (non-credit OTTI) is recognized in OCI. Included in the “OTTI Recognized in AOCI” columns above are the cumulative amounts of non-credit OTTI recognized in OCI adjusted for subsequent sales, maturities, and redemptions. OTTI recognized in AOCI does not include the impact of subsequent changes in fair value of the related securities. In periods subsequent to a recognition of OTTI in OCI, changes in the fair value of the related fixed maturities are reflected in Net unrealized appreciation on investments in the Consolidated statements of shareholders’ equity. For the three and six months ended June 30, 2018, nil and $4 million, respectively, of net unrealized depreciation related to such securities is included in OCI. For both the three and six months ended June 30, 2017, $3 million of net unrealized depreciation related to such securities is included in OCI. At June 30, 2018 and December 31, 2017, AOCI included cumulative net unrealized appreciation of $3 million and $7 million, respectively, related to securities remaining in the investment portfolio for which a non-credit OTTI was recognized.

Mortgage-backed securities (MBS) issued by U.S. government agencies are combined with all other to be announced mortgage-backed securities (TBAs) held (refer to Note 6 b) (iv)) and are included in the category, “Mortgage-backed securities”. Approximately 81 percent and 83 percent of the total mortgage-backed securities at June 30, 2018 and December 31, 2017, respectively, are represented by investments in U.S. government agency bonds. The remainder of the mortgage exposure consists of collateralized mortgage obligations and non-government mortgage-backed securities, the majority of which provide a planned structure for principal and interest payments and carry a rating of AAA by the major credit rating agencies.

The following table presents fixed maturities by contractual maturity:



			June 30				December 31
			2018				2017
(in millions of U.S. dollars)	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Available for sale
Due in 1 year or less	$	3,801	$	3,808	$	3,164	$	3,182
Due after 1 year through 5 years	26,591		26,583		24,749		25,068
Due after 5 years through 10 years	24,016		23,695		25,388		25,704
Due after 10 years	8,285		8,394		9,255		9,695
	62,693		62,480		62,556		63,649
Mortgage-backed securities	15,853		15,483		15,279		15,290
	$	78,546	$	77,963	$	77,835	$	78,939
Held to maturity
Due in 1 year or less	$	644	$	645	$	743	$	746
Due after 1 year through 5 years	2,783		2,767		2,669		2,688
Due after 5 years through 10 years	4,634		4,554		4,744		4,756
Due after 10 years	3,159		3,114		3,455		3,542
	11,220		11,080		11,611		11,732
Mortgage-backed securities	2,640		2,585		2,724		2,742
	$	13,860	$	13,665	$	14,335	$	14,474

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) Net realized gains (losses)

In accordance with guidance related to the recognition and presentation of OTTI, when an impairment related to a fixed maturity has occurred, OTTI is required to be recorded in Net income if management has the intent to sell the security or it is more likely than not that we will be required to sell the security before the recovery of its amortized cost. Further, in cases where we do not intend to sell the security and it is more likely than not that we will not be required to sell the security, we must evaluate the security to determine the portion of the impairment, if any, related to credit losses. If a credit loss is incurred, an OTTI is considered to have occurred and any portion of the OTTI related to credit losses must be reflected in Net income while the portion of OTTI related to all other factors is recognized in OCI. For fixed maturities held to maturity, OTTI recognized in OCI is accreted from AOCI to the amortized cost of the fixed maturity prospectively over the remaining term of the securities.

Each quarter, securities in an unrealized loss position (impaired securities), including fixed maturities and securities lending collateral are reviewed to identify impaired securities to be specifically evaluated for a potential OTTI. Refer to the 2017 Form 10-K for information on our evaluation of OTTI for all non-fixed maturities prior to our adoption of new accounting guidance on financial instruments, effective January 1, 2018.

Evaluation of potential credit losses related to fixed maturities

We review each fixed maturity in an unrealized loss position to assess whether the security is a candidate for credit loss. Specifically, we consider credit rating, market price, and issuer-specific financial information, among other factors, to assess the likelihood of collection of all principal and interest as contractually due. Securities for which we determine that credit loss is likely are subjected to further analysis to estimate the credit loss recognized in Net income, if any. In general, credit loss recognized in Net income equals the difference between the security’s amortized cost and the net present value of its projected future cash flows discounted at the effective interest rate implicit in the debt security. All significant assumptions used in determining credit losses are subject to change as market conditions evolve.

Corporate securities

Projected cash flows for corporate securities (principally senior unsecured bonds) are driven primarily by assumptions regarding probability of default and also the timing and amount of recoveries associated with defaults. Chubb developed projected cash flows for corporate securities using market observable data, issuer-specific information, and credit ratings. We use historical default data by Moody’s Investors Service (Moody’s) rating category to calculate a 1-in-100 year probability of default, which results in a default assumption in excess of the historical mean default rate. Consistent with management's approach, Chubb assumed a 32 percent recovery rate (the par value of a defaulted security that will be recovered) across all rating categories rather than using Moody's historical mean recovery rate of 42 percent. We believe that use of a default assumption in excess of the historical mean is conservative.

For both the three and six months ended June 30, 2018, credit losses recognized in Net income for corporate securities were $1 million. For the three and six months ended June 30, 2017, credit losses recognized in Net income for corporate securities were $1 million and $2 million, respectively.

Mortgage-backed securities

For mortgage-backed securities, credit impairment is assessed using a cash flow model that estimates the cash flows on the underlying mortgages, using the security-specific collateral and transaction structure. The model estimates cash flows from the underlying mortgage loans and distributes those cash flows to various tranches of securities, considering the transaction structure and any subordination and credit enhancements that exist in that structure. The cash flow model incorporates actual cash flows on the mortgage-backed securities through the current period and then projects the remaining cash flows using a number of assumptions, including default rates, prepayment rates, and loss severity rates (the par value of a defaulted security that will not be recovered) on foreclosed properties.

For the three and six months ended June 30, 2018 and 2017, there were no credit losses recognized in Net income for mortgage-backed securities.

The following table presents the components of Net realized gains (losses):



	Three Months Ended						Six Months Ended
	June 30						June 30
(in millions of U.S. dollars)	2018			2017			2018			2017
Fixed maturities:
OTTI on fixed maturities, gross	$	(4	)	$	(5	)	$	(5	)	$	(11	)
OTTI on fixed maturities recognized in OCI (pre-tax)	—			1			—			1
OTTI on fixed maturities, net	(4		)	(4		)	(5		)	(10		)
Gross realized gains excluding OTTI	99			45			165			79
Gross realized losses excluding OTTI	(176		)	(18		)	(264		)	(58		)
Total fixed maturities	(81		)	23			(104		)	11
Equity securities:
OTTI on equity securities	—			(3		)	—			(8		)
Gross realized gains excluding OTTI	6			6			16			15
Gross realized losses excluding OTTI	(8		)	(1		)	(29		)	(1		)
Total equity securities	(2		)	2			(13		)	6
OTTI on other investments	—			(1		)	—			(9		)
Other investments	(11		)	—			18			—
Foreign exchange gains (losses)	140			14			63			(5		)
Investment and embedded derivative instruments	24			(16		)	41			(10		)
Fair value adjustments on insurance derivative	41			118			79			211
S&P put options and futures	(44		)	(38		)	(22		)	(112		)
Other derivative instruments	8			(1		)	10			1
Other	(57		)	—			(56		)	1
Net realized gains (losses)	$	18		$	101		$	16		$	94

Other net realized gains (losses) for the three and six months ended June 30, 2018, included a $36 million loss from the extinguishment of debt as discussed in Note 5 and a $22 million loss related to lease impairments.

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:



	Three Months Ended					Six Months Ended
	June 30					June 30
(in millions of U.S. dollars)	2018		2017			2018			2017
Balance of credit losses related to securities still held – beginning of period	$	15	$	32		$	22		$	35
Additions where no OTTI was previously recorded	1		1			1			1
Additions where an OTTI was previously recorded	—		—			—			1
Reductions for securities sold during the period	—		(4		)	(7		)	(8		)
Balance of credit losses related to securities still held – end of period	$	16	$	29		$	16		$	29

c) Equity securities and Other investments

Effective January 1, 2018, we adopted new accounting guidance that requires any changes in fair value of equity securities and other investments that are accounted for under the cost-method to be recognized immediately in realized gains and losses in net income. As a result, beginning on January 1, 2018, realized gains and losses from these investments include both sales of securities and unrealized gains and losses as follows:



	Three Months Ended									Six Months Ended
	June 30, 2018									June 30, 2018
(in millions of U.S. dollars)	Equity Securities			Other Investments			Total			Equity Securities			Other Investments		Total
Net gains (losses) recognized during the period	$	(2	)	$	(11	)	$	(13	)	$	(13	)	$	18	$	5
Less: Net gains (losses) recognized from sales of securities	5			—			5			15			—		15
Unrealized gains (losses) recognized for securities still held at reporting date	$	(7	)	$	(11	)	$	(18	)	$	(28	)	$	18	$	(10	)

At December 31, 2017, the cost, gross unrealized appreciation, gross unrealized depreciation, and fair value of equity securities was $737 million, $212 million, $12 million, and $937 million, respectively. At December 31, 2017, the net unrealized appreciation (depreciation) was recorded within accumulated other comprehensive income on the balance sheet.

d) Gross unrealized loss

At June 30, 2018, there were 17,926 fixed maturities out of a total of 31,062 fixed maturities in an unrealized loss position. The largest single unrealized loss in the fixed maturities was $11 million. Fixed maturities in an unrealized loss position at June 30, 2018, 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 tables present, 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
June 30, 2018	Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)	Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss
U.S. Treasury and agency	$	2,952	$	(59	)	$	1,275	$	(41	)	$	4,227	$	(100	)
Foreign	8,886		(219		)	3,127		(92		)	12,013		(311		)
Corporate securities	15,899		(411		)	1,553		(89		)	17,452		(500		)
Mortgage-backed securities	12,438		(325		)	2,892		(147		)	15,330		(472		)
States, municipalities, and political subdivisions	13,551		(177		)	1,230		(47		)	14,781		(224		)
Total fixed maturities	$	53,726	$	(1,191	)	$	10,077	$	(416	)	$	63,803	$	(1,607	)



	0 – 12 Months					Over 12 Months					Total
December 31, 2017	Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)	Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss
U.S. Treasury and agency	$	2,172	$	(14	)	$	1,249	$	(26	)	$	3,421	$	(40	)
Foreign	5,657		(65		)	1,693		(49		)	7,350		(114		)
Corporate securities	5,210		(56		)	1,332		(46		)	6,542		(102		)
Mortgage-backed securities	6,194		(31		)	3,209		(74		)	9,403		(105		)
States, municipalities, and political subdivisions	9,259		(71		)	1,402		(32		)	10,661		(103		)
Total fixed maturities	28,492		(237		)	8,885		(227		)	37,377		(464		)
Equity securities	115		(12		)	—		—			115		(12		)
Other investments	78		(8		)	—		—			78		(8		)
Total	$	28,685	$	(257	)	$	8,885	$	(227	)	$	37,570	$	(484	)

e) 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 also 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 also have investments in segregated portfolios primarily to provide collateral or guarantees for LOC and derivative transactions. Included in restricted assets at June 30, 2018 and December 31, 2017 are investments, primarily fixed maturities, totaling $21.2 billion and $23.3 billion, respectively, and cash of $101 million and $123 million, respectively.

The following table presents the components of restricted assets:



	June 30		December 31
(in millions of U.S. dollars)	2018		2017
Trust funds	$	14,775	$	17,011
Deposits with U.S. regulatory authorities	2,460		2,345
Deposits with non-U.S. regulatory authorities	2,206		2,250
Assets pledged under repurchase agreements	1,449		1,434
Other pledged assets	407		414
	$	21,297	$	23,454

Fair value measurements

6 Months Ended

Jun. 30, 2018

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. Accordingly, transfers between levels within the valuation hierarchy occur when there are significant changes to the inputs, such as increases or decreases in market activity, changes to the availability of current prices, changes to the transparency to underlying inputs, and whether there are significant variances in quoted prices. Transfers in and/or out of any level are assumed to occur at the end of the period.

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, 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), which 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 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 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 generally maintain positions in other derivative instruments including exchange-traded equity futures contracts and option contracts designed to limit exposure to a severe equity market decline, which would cause an increase in expected claims and, therefore, an increase in reserves for our guaranteed minimum death benefits (GMDB) and guaranteed living benefits (GLB) reinsurance business. Our position in exchange-traded equity futures contracts is 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. We also assume the risk of guaranteed minimum accumulation benefits (GMAB). However, at June 30, 2018, the risks related to our GMAB programs are minimal given that the majority of these policies are no longer in-force. GLB’s are recorded in Accounts payable, accrued expenses, and other liabilities and Future policy benefits in the Consolidated balance sheets. 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.

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.

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.

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. Because of the significant use of unobservable inputs including policyholder behavior, GLB reinsurance is classified within Level 3. For the three and six months ended June 30, 2018, no material technical refinements were made to the model. During the three months ended June 30, 2017, we updated aspects of our valuation model relating to interest rates. This resulted in a decrease to the fair value of GLB liabilities generating a realized gain of approximately $94 million. During the six months ended June 30, 2017, there were no other material changes to actuarial or behavioral assumptions. For detailed information on our lapse and annuitization rate assumptions, refer to Note 4 to the Consolidated Financial Statements of our 2017 Form 10-K.

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



June 30, 2018	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities available for sale
U.S. Treasury and agency	$	2,939	$	825	$	—	$	3,764
Foreign	—		21,759		252		22,011
Corporate securities	—		23,304		1,181		24,485
Mortgage-backed securities	—		15,401		82		15,483
States, municipalities, and political subdivisions	—		12,220		—		12,220
	2,939		73,509		1,515		77,963
Equity securities	874		—		59		933
Short-term investments	1,750		1,409		12		3,171
Other investments ⁽¹⁾	424		326		264		1,014
Securities lending collateral	—		2,355		—		2,355
Investment derivative instruments	39		—		—		39
Other derivative instruments	50		—		—		50
Separate account assets	2,862		116		—		2,978
Total assets measured at fair value ⁽¹⁾	$	8,938	$	77,715	$	1,850	$	88,503
Liabilities:
Investment derivative instruments	$	42	$	—	$	—	$	42
Other derivative instruments	—		—		2		2
GLB ⁽²⁾	—		—		125		125
Total liabilities measured at fair value	$	42	$	—	$	127	$	169


⁽¹⁾	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,224 million and other investments of $21 million at June 30, 2018 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. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.



December 31, 2017	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities available for sale
U.S. Treasury and agency	$	3,129	$	569	$	—	$	3,698
Foreign	—		20,937		93		21,030
Corporate securities	—		22,959		1,037		23,996
Mortgage-backed securities	—		15,212		78		15,290
States, municipalities, and political subdivisions	—		14,925		—		14,925
	3,129		74,602		1,208		78,939
Equity securities	893		—		44		937
Short-term investments	2,309		1,252		—		3,561
Other investments ⁽¹⁾	466		305		263		1,034
Securities lending collateral	—		1,737		—		1,737
Investment derivative instruments	18		—		—		18
Other derivative instruments	1		—		—		1
Separate account assets	2,635		99		—		2,734
Total assets measured at fair value ⁽¹⁾	$	9,451	$	77,995	$	1,515	$	88,961
Liabilities:
Investment derivative instruments	$	30	$	—	$	—	$	30
Other derivative instruments	21		—		2		23
GLB ⁽²⁾	—		—		204		204
Total liabilities measured at fair value	$	51	$	—	$	206	$	257


⁽¹⁾	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $3,623 million and other investments of $15 million at December 31, 2017 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. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.

There were no transfers of financial instruments between Level 1 and Level 2 for both the three and six months ended June 30, 2018 and 2017.

Fair value of alternative investments

Alternative investments include investment funds, limited partnerships, and partially-owned investment companies measured at fair value using 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:



				June 30				December 31
	Expected Liquidation Period of Underlying Assets			2018				2017
(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	5 to 9 Years	$	569	$	281	$	540	$	330
Real Assets	3 to 7 Years	673		192		651		114
Distressed	3 to 7 Years	279		131		289		141
Private Credit	3 to 7 Years	184		308		187		327
Traditional	3 to 15 Years	2,177		2,529		1,656		3,149
Vintage	1 to 2 Years	64		—		30		—
Investment funds	Not Applicable	278		—		270		—
		$	4,224	$	3,441	$	3,623	$	4,061

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		made before 2002 or where the funds’ commitment periods had already expired

Investment funds

Chubb’s 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 range between 5 and 120 days. Chubb can redeem its investment funds without consent from the investment fund managers.

Level 3 financial instruments

The fair values of assets and liabilities measured at fair value using significant unobservable inputs (Level 3) consist of various inputs and assumptions that management makes when determining fair value. Management analyzes changes in fair value measurements classified within Level 3 by comparing pricing and returns of our investments to benchmarks, including month-over-month movements, investment credit spreads, interest rate movements, and credit quality of securities.

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.

(in millions of U.S. dollars, except for percentages)

Fair Value

Valuation

Technique

Significant

Unobservable Inputs

Ranges

June 30, 2018

December 31, 2017

GLB ⁽¹⁾

$

125

$

204

Actuarial model

Lapse rate

3% – 33%

Annuitization rate

0% – 100%


⁽¹⁾	Discussion of the most significant inputs used in the fair value measurement of GLB and the sensitivity of those assumptions is included within Note 3 a) Guaranteed living benefits.

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
Three Months Ended	Available-for-Sale Debt Securities									Equity securities			Short-term investments			Other investments			Other derivative instruments		GLB ⁽²⁾
June 30, 2018	Foreign			Corporate securities ⁽¹⁾			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities ⁽¹⁾			MBS
Balance – beginning of period	$	176		$	1,073		$	83		$	64		$	12		$	270		$	2	$	167
Transfers into Level 3	—			6			—			—			—			—			—		—
Transfers out of Level 3	—			—			—			—			—			—			—		—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	(7		)	(9		)	—			—			—			—			—		—
Net Realized Gains/Losses	—			2			—			(3		)	—			1			—		(42		)
Purchases	95			217			—			3			1			16			—		—
Sales	(11		)	(45		)	—			(5		)	—			—			—		—
Settlements	(1		)	(63		)	(1		)	—			(1		)	(23		)	—		—
Balance – end of period	$	252		$	1,181		$	82		$	59		$	12		$	264		$	2	$	125
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—		$	(3	)	$	—		$	1		$	—	$	(42	)


⁽¹⁾	Purchases in Level 3 primarily consist of privately-placed fixed income securities.

⁽²⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $529 million at March 31, 2018, which includes a fair value derivative adjustment of $125 million and $167 million, respectively.



	Assets																				Liabilities
Three Months Ended	Available-for-Sale Debt Securities								Equity securities			Short-term investments			Other investments			Other derivative instruments			GLB ⁽¹⁾
June 30, 2017	Foreign			Corporate securities			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities			MBS
Balance – beginning of period	$	80		$	737		$	45	$	41		$	21		$	233		$	11		$	466
Transfers into Level 3	—			28			—		—			—			—			—			9
Transfers out of Level 3	—			(13		)	—		—			—			—			(9		)	—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	3			—			—		1			—			(1		)	—			—
Net Realized Gains/Losses	2			—			—		—			—			—			—			(118		)
Purchases	19			65			—		6			7			16			—			—
Sales	(19		)	(28		)	—		(9		)	—			—			—			—
Settlements	—			(42		)	—		—			(21		)	(5		)	—			—
Balance – end of period	$	85		$	747		$	45	$	39		$	7		$	243		$	2		$	357
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—	$	—		$	—		$	—		$	—		$	(118	)

⁽¹⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $774 million at March 31, 2017, which includes a fair value derivative adjustment of $357 million and $466 million, respectively.



	Assets																		Liabilities
Six Months Ended	Available-for-Sale Debt Securities									Equity securities			Short-term investments			Other investments			Other derivative instruments		GLB⁽²⁾
June 30, 2018	Foreign			Corporate securities ⁽¹⁾			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities ⁽¹⁾			MBS
Balance – beginning of period	$	93		$	1,037		$	78		$	44		$	—		$	263		$	2	$	204
Transfers into Level 3	7			6			1			—			5			—			—		—
Transfers out of Level 3	—			(10		)	—			—			—			—			—		—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	2			(12		)	—			1			—			2			—		—
Net Realized Gains/Losses	—			2			—			(1		)	—			1			—		(79		)
Purchases	182			356			4			20			9			30			—		—
Sales	(30		)	(96		)	—			(5		)	—			—			—		—
Settlements	(2		)	(102		)	(1		)	—			(2		)	(32		)	—		—
Balance – end of period	$	252		$	1,181		$	82		$	59		$	12		$	264		$	2	$	125
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—		$	(1	)	$	—		$	1		$	—	$	(79	)


⁽¹⁾	Purchases in Level 3 primarily consist of privately-placed fixed income securities.

⁽²⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $550 million at December 31, 2017, which includes a fair value derivative adjustment of $125 million and $204 million, respectively.



	Assets																					Liabilities
Six Months Ended	Available-for-Sale Debt Securities									Equity securities			Short-term investments			Other investments			Other derivative instruments			GLB⁽¹⁾
June 30, 2017	Foreign			Corporate securities			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities			MBS
Balance – beginning of period	$	74		$	681		$	45		$	41		$	25		$	225		$	13		$	559
Transfers into Level 3	—			57			—			—			—			—			—			9
Transfers out of Level 3	—			(67		)	—			—			—			—			(9		)	—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	2			(8		)	—			1			—			3			—			—
Net Realized Gains/Losses	1			(1		)	—			—			—			—			(2		)	(211		)
Purchases	33			221			1			6			14			24			—			—
Sales	(22		)	(55		)	(1		)	(9		)	—			—			—			—
Settlements	(3		)	(81		)	—			—			(32		)	(9		)	—			—
Balance – end of period	$	85		$	747		$	45		$	39		$	7		$	243		$	2		$	357
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—		$	—		$	—		$	—		$	(2	)	$	(211	)

⁽¹⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $853 million at December 31, 2016, which includes a fair value derivative adjustment of $357 million and $559 million, respectively.

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.

Refer to the 2017 Form 10-K for information on the fair value methods and assumptions for investments in partially-owned insurance companies, short-term and long-term debt, repurchase agreements, and trust-preferred securities.

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



June 30, 2018	Fair Value								Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total		Carrying Value
Assets:
Fixed maturities held to maturity
U.S. Treasury and agency	$	1,079	$	54	$	—	$	1,133	$	1,143
Foreign	—		1,675		—		1,675		1,678
Corporate securities	—		2,633		32		2,665		2,736
Mortgage-backed securities	—		2,585		—		2,585		2,640
States, municipalities, and political subdivisions	—		5,607		—		5,607		5,663
Total assets	$	1,079	$	12,554	$	32	$	13,665	$	13,860
Liabilities:
Repurchase agreements	$	—	$	1,413	$	—	$	1,413	$	1,413
Short-term debt	—		615		—		615		600
Long-term debt	—		12,296		—		12,296		12,184
Trust preferred securities	—		433		—		433		308
Total liabilities	$	—	$	14,757	$	—	$	14,757	$	14,505



December 31, 2017	Fair Value								Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total		Carrying Value
Assets:
Fixed maturities held to maturity
U.S. Treasury and agency	$	857	$	58	$	—	$	915	$	908
Foreign	—		1,757		—		1,757		1,738
Corporate securities	—		3,184		35		3,219		3,159
Mortgage-backed securities	—		2,742		—		2,742		2,724
States, municipalities, and political subdivisions	—		5,841		—		5,841		5,806
Total assets	$	857	$	13,582	$	35	$	14,474	$	14,335
Liabilities:
Repurchase agreements	$	—	$	1,408	$	—	$	1,408	$	1,408
Short-term debt	—		1,013		—		1,013		1,013
Long-term debt	—		12,332		—		12,332		11,556
Trust preferred securities	—		468		—		468		308
Total liabilities	$	—	$	15,221	$	—	$	15,221	$	14,285

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.

Liability for Claims and Claims Adjustment Expense [Abstract]

Unpaid losses and loss expenses

6 Months Ended

Jun. 30, 2018

Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block]

Unpaid losses and loss expenses

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



	Six Months Ended June 30
(in millions of U.S. dollars)	2018			2017
Gross unpaid losses and loss expenses – beginning of period	$	63,179		$	60,540
Reinsurance recoverable on unpaid losses - beginning of period ⁽¹⁾	(14,014		)	(12,708		)
Net unpaid losses and loss expenses – beginning of period	49,165			47,832
Net losses and loss expenses incurred in respect of losses occurring in:
Current year	9,026			8,396
Prior years ⁽²⁾	(437		)	(461		)
Total	8,589			7,935
Net losses and loss expenses paid in respect of losses occurring in:
Current year	2,346			2,271
Prior years	6,269			5,758
Total	8,615			8,029
Foreign currency revaluation and other	(96		)	171
Net unpaid losses and loss expenses – end of period	49,043			47,909
Reinsurance recoverable on unpaid losses ⁽³⁾	13,735			12,485
Gross unpaid losses and loss expenses – end of period	$	62,778		$	60,394


⁽¹⁾	Net of provision for uncollectible reinsurance of $321 million and $300 million at December 31, 2017 and 2016, respectively.


⁽²⁾	Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments, and earned premiums totaling $37 million and $60 million for the six months ended June 30, 2018 and 2017, respectively.


⁽³⁾	Net of provision for uncollectible reinsurance of $319 million and $335 million at June 30, 2018 and 2017, respectively.

The decrease in net unpaid losses and loss expenses from December 31, 2017 was primarily due to payments related to the 2017 catastrophic events.

Prior Period Development

Prior period development 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. 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.

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. During the third quarter of 2017, we determined that the loss development classification for certain businesses, previously grouped within the short-tail column in the table below, would be more appropriately grouped within the long-tail column to better align with the classification of these businesses within our loss development triangles in our Form 10-K. We also determined that the loss development for certain other businesses should be reclassified from long-tail to short-tail. We updated the 2017 amounts below to conform to the current period presentation and reclassified $2 million of net favorable development and $3 million of net adverse development into long-tail from short-tail for the three and six months ended June 30, 2017, respectively. These changes to the previously disclosed amounts have no impact to our financial condition and results of operations.

Favorable prior period development for the three months ended June 30, 2018 of $191 million included $236 million of

favorable development, of which $136 million was long-tail lines, principally for the 2014 and prior accident years, $64 million

was short-tail lines, and $36 million was related to the 2017 catastrophe events. The favorable development was offset by $45 million of adverse development related to our run-off non-A&E casualty exposures.

Favorable prior period development for the six months ended June 30, 2018 of $400 million included $455 million of

favorable development, of which $125 million was long-tail lines, principally for 2014 and prior accident years, $188 million was short-tail lines, principally related to our Crop insurance business, and $142 million was related to the 2017 catastrophe events. The favorable development was offset by $55 million of adverse development related to our run-off non-A&E casualty exposures.



	Three Months Ended June 30									Six Months Ended June 30
(in millions of U.S. dollars)	Long-tail			Short-tail			Total			Long-tail			Short-tail			Total
2018
North America Commercial P&C Insurance	$	(104	)	$	(51	)	$	(155	)	$	(96	)	$	(160	)	$	(256	)
North America Personal P&C Insurance	—			7			7			—			1			1
North America Agricultural Insurance	—			—			—			—			(76		)	(76		)
Overseas General Insurance	(2		)	(70		)	(72		)	(2		)	(92		)	(94		)
Global Reinsurance	(30		)	14			(16		)	(30		)	—			(30		)
Corporate	45			—			45			55			—			55
Total	$	(91	)	$	(100	)	$	(191	)	$	(73	)	$	(327	)	$	(400	)
2017
North America Commercial P&C Insurance	$	(83	)	$	(48	)	$	(131	)	$	(177	)	$	(133	)	$	(310	)
North America Personal P&C Insurance	—			37			37			—			34			34
North America Agricultural Insurance	—			—			—			—			(79		)	(79		)
Overseas General Insurance	—			(88		)	(88		)	32			(108		)	(76		)
Global Reinsurance	(36		)	5			(31		)	(28		)	5			(23		)
Corporate	43			—			43			53			—			53
Total	$	(76	)	$	(94	)	$	(170	)	$	(120	)	$	(281	)	$	(401	)

North America Commercial P&C Insurance

2018

For the three months ended June 30, 2018, net favorable PPD was $155 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 $104 million in long-tail business, primarily from:

•

Net favorable development of $118 million in our workers’ compensation lines with favorable development of $56 million in the 2017 accident year mainly related to our annual assessment of multi-claimant events including industrial accidents. 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. The remaining favorable development is mainly in accident years 2011 and prior, and was principally due to lower than expected loss experience; and


•	Net adverse development of $14 million, mainly in our automobile liability, commercial-multi peril (CMP) liability, products and general liability lines, driven by adverse paid and reported loss activity relative to prior expectations in accident years 2015 through 2017, partly offset by favorable emergence in older accident years.


•	Net favorable development of $51 million in short-tail business, primarily from:


•	Net favorable development of $40 million in our commercial property and marine businesses due to favorable claim development on the 2017 natural catastrophes.

For the six months ended June 30, 2018, net favorable PPD was $256 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 $96 million in long-tail business, primarily from:


•	Net favorable development of $138 million in our workers’ compensation lines mainly due to the same factors experienced for the three months ended June 30, 2018, as described above;

•

Net favorable development of $29 million in our commercial excess and umbrella portfolios, driven by the 2012 and prior accident years where the cumulative emergence over time has been less than expected overall and an increase in weighting towards experience-based methods, partly offset by several large settlements; additionally there was adverse claim activity in the 2014 and 2015 accident years which led to reserve strengthening in those years;


•	Net favorable development of $3 million on several lines of business due to favorable claim development on the 2017 natural catastrophes; and


•	Net adverse development of $74 million, mainly in our automobile liability, commercial-multi peril (CMP) liability, products and general liability lines, due to the same factors experienced for the three months ended June 30, 2018, as described above.


•	Net favorable development of $160 million in short-tail business, primarily from:


•	Net favorable development of $115 million in our commercial property and marine businesses due to favorable claim development on the 2017 natural catastrophes; and


•	Net favorable development of $45 million in other short-tail business, including $19 million in surety and also including several smaller net favorable movements from lower than expected case activity in other classes, such as accident and commercial automobile physical damage, none of which were significant individually or in the aggregate.

2017

For the three months ended June 30, 2017, net favorable PPD was $131 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 $83 million in long-tail business, primarily from:

•

Net favorable development of $75 million in our workers’ compensation lines with favorable development of $57 million in the 2016 accident year related to our annual assessment of multi-claimant events including industrial accidents. 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. Favorable development of $38 million in accident years 2015 and prior was principally due to lower than expected loss experience and revision to development patterns used in our loss projection methods for select portfolios; and


•	Net favorable development of $48 million in short-tail business, primarily from favorable development of $45 million in our commercial property portfolios, driven by lower than expected loss emergence in the 2014 and 2016 accident years.

For the six months ended June 30, 2017, net favorable PPD was $310 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 $177 million in long-tail business, primarily from:


•	Net favorable development of $79 million in our workers’ compensation lines due to the same factors experienced for the three months ended June 30, 2017, as described above;


•	Net favorable development of $74 million in our commercial excess and umbrella portfolios, primarily in accident years 2010 and prior, driven by lower than expected reported loss activity, and an increase in weighting towards experience-based methods; and


•	Net favorable development of $25 million in our professional Errors and Omissions (E&O) portfolios, primarily in the 2012 and 2013 accident years, arising from lower than expected reported loss activity, partially offset by claim-specific adverse development.


•	Net favorable development of $133 million in short-tail business, primarily from:


•	Net favorable development of $45 million in our surety business, primarily due to lower than expected claims severity in the 2015 accident year;


•	Favorable development of $57 million in our property lines, primarily in our commercial property portfolios, due to the same factors experienced for the three months ended June 30, 2017 as described above; and


•	Net favorable development of $19 million in our accident & health (A&H) business, primarily due to lower than expected loss emergence in the 2015 and 2016 accident years.

North America Personal P&C Insurance

2018

For the three and six months ended June 30, 2018, net adverse PPD was $7 million and $1 million, respectively, which were the net results of some modest net adverse and favorable movements by class and accident year, including favorable development of $5 million and $11 million, respectively, on the 2017 natural catastrophes.

2017

For the three and six months ended June 30, 2017, net adverse PPD was $37 million and $34 million, respectively, driven primarily by higher than expected case incurred development in our automobile, recreational marine and homeowners lines, mainly in accident years 2012 through 2016.

North America Agricultural Insurance

There was no PPD for the three months ended June 30, 2018 and 2017.

For the six months ended June 30, 2018 and 2017, net favorable PPD was $76 million and $79 million, respectively. Actual claim development relates to our Multiple Peril Crop Insurance (MPCI) business and is favorable due to better than expected crop yield results in certain states at the prior year-end period (i.e., 2018 results based on crop yield results at year-end 2017).

Overseas General Insurance

2018

For the three months ended June 30, 2018, net favorable PPD was $72 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 $2 million in long-tail business.


•	Net favorable development of $70 million in short-tail business, primarily from:


•	Net favorable development of $40 million in property and marine (excluding technical lines), primarily in accident years 2014 through 2016, driven mainly by favorable loss emergence across all regions, including favorable claim-specific loss settlements; and


•	Net favorable development of $30 million, including $17 million in personal business and $16 million in A&H business.

For the six months ended June 30, 2018, net favorable PPD was $94 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 $2 million in long-tail business.


•	Net favorable development of $92 million in short-tail business, due primarily to the same factors experienced for the three months ended June 30, 2018 as described above, and due to $12 million of favorable claim development on the 2017 natural catastrophes.

2017

For the three months ended June 30, 2017, net favorable PPD was $88 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 $88 million in short-tail business, primarily from:


•	Favorable development of $37 million in property and marine (excluding technical lines), primarily in accident years 2013 through 2015, driven mainly by favorable U.K. and Continental Europe loss emergence, including favorable claim-specific loss settlements;


•	Favorable development of $26 million in technical and energy lines, primarily from favorable loss emergence in accident years 2014 through 2016 primarily in offshore where experience has been better than expected; and


•	Favorable development of $19 million in A&H lines, primarily from favorable loss emergence in Asia Pacific and Continental Europe in accident years 2014 through 2016.

For the six months ended June 30, 2017, net favorable PPD was $76 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 $108 million in short-tail business, due primarily to the same factors experienced for the three months ended June 30, 2017 as described above; and


•	Net adverse development of $32 million in long-tail business, primarily in our casualty lines, driven by a change in the discount rate in the U.K. (Ogden rate) impacting the 2016 and prior accident years.

Global Reinsurance

2018

For the three months ended June 30, 2018, net favorable PPD was $16 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 $30 million in long-tail business, primarily from $32 million favorable development in our casualty and professional liability lines, primarily impacting treaty years 2013 and prior, principally resulting from lower than expected loss emergence.


•	Net adverse development of $14 million in short-tail business, which included $9 million of adverse claim development on the 2017 natural catastrophes.

For the six months ended June 30, 2018, net favorable PPD was $30 million, which was the net result of several underlying favorable and adverse movements, primarily from long-tail business lines discussed above, and in short-tail business due to $1 million of net favorable claim development on the 2017 natural catastrophes.

2017

For the three months ended June 30, 2017, net favorable PPD was $31 million, which was the net result of several underlying favorable and adverse movements, and was driven by the following principal change:


•	Net favorable development of $36 million in our casualty and professional liability lines, primarily impacting treaty years 2011 and prior, principally resulting from lower than expected loss emergence.

For the six months ended June 30, 2017, net favorable PPD was $23 million, which was the net result of several underlying favorable and adverse movements, and was driven by the following principal change:


•	Net favorable development of $27 million, comprising $36 million in our casualty and professional liability lines as described above, as well as adverse development of $9 million in our motor and excess liability lines, driven by a change in the discount rate in the U.K. (Ogden rate) primarily impacting the 2015 and prior treaty years.

Corporate

2018

For the three and six months ended June 30, 2018, net adverse development was $45 million and $55 million, respectively, from the non A&E run-off casualty exposures, driven by recent net adverse settlements on a limited number of claims and reinsurance collection activity. The net adverse development also included charges relating to unallocated loss adjustment expenses due to run-off operating expenses of $10 million and $20 million, respectively.

2017

For the three and six months ended June 30, 2017, adverse development was $43 million and $53 million, respectively, due principally to development of $35 million on non A&E run-off casualty exposures due to higher than expected loss activity, and unallocated loss adjustment expenses due to run-off operating expenses paid and incurred in the respective periods of $8 million and $18 million, respectively.

Debt	6 Months Ended
Debt	Jun. 30, 2018
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	Debt In March 2018, Chubb INA Holdings Inc. (Chubb INA) issued €900 million ($1.1 billion based on the foreign exchange rate at the date of issuance) of 1.55 percent Euro denominated senior notes due March 2028 and €900 million ($1.1 billion based on the foreign exchange rate at the date of issuance) of 2.5 percent Euro denominated senior notes due March 2038. These senior notes are redeemable at any time at Chubb INA's option subject to a “make-whole” premium (the present value of the remaining principal and interest discounted at the applicable comparable government bond rate plus 0.15 percent for the senior notes due 2028 and 0.25 percent for the senior notes due 2038). The notes are also redeemable at par plus accrued and unpaid interest in the event of certain changes in tax law. These notes do not have the benefit of any sinking fund. These senior unsecured notes are guaranteed on a senior basis by Chubb 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. Chubb INA's $300 million of 5.8 percent senior notes due March 2018 and $600 million of 5.75 percent senior notes due May 2018 were paid upon maturity. During April 2018, we redeemed $1.0 billion of 6.375 percent unsecured junior subordinated capital securities due to mature in April 2037 and recorded a loss of $36 million from the extinguishment of debt, which is included in Net realized gains (losses) in the Consolidated statement of operations. In June 2018, we reclassified $499 million of the 5.9 percent senior notes ($500 million par value due to mature in June 2019) from long-term to short-term debt in the Consolidated balance sheets.

Commitments, contingencies, and guarantees

6 Months Ended

Jun. 30, 2018

Commitments and Contingencies Disclosure [Abstract]

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 from time to time 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. Benefit reserves in respect of GLBs are classified as Future policy benefits (FPB) while the fair value derivative adjustment 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 blocks 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:



				June 30, 2018							December 31, 2017
	Consolidated Balance Sheet Location	Fair Value					Notional Value/ Payment Provision		Fair Value					Notional Value/ Payment Provision
(in millions of U.S. dollars)	Consolidated Balance Sheet Location	Derivative Asset		Derivative (Liability)			Notional Value/ Payment Provision		Derivative Asset		Derivative (Liability)			Notional Value/ Payment Provision
Investment and embedded derivative instruments:
Foreign currency forward contracts	OA / (AP)	$	33	$	(36	)	$	2,364	$	14	$	(27	)	$	2,064
Cross-currency swaps	OA / (AP)	—		—			45		—		—			45
Options/Futures contracts on notes and bonds	OA / (AP)	6		(6		)	1,409		4		(3		)	1,007
Convertible securities ⁽¹⁾	FM AFS / ES	9		—			10		5		—			6
		$	48	$	(42	)	$	3,828	$	23	$	(30	)	$	3,122
Other derivative instruments:
Futures contracts on equities⁽²⁾	OA / (AP)	$	32	$	—		$	1,632	$	—	$	(21	)	$	1,553
Other	OA / (AP)	18		(2		)	351		1		(2		)	75
		$	50	$	(2	)	$	1,983	$	1	$	(23	)	$	1,628
GLB ⁽³⁾	(AP) / (FPB)	$	—	$	(497	)	$	1,163	$	—	$	(550	)	$	1,083


⁽¹⁾	Includes fair value of embedded derivatives.


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


⁽³⁾	Includes both future policy benefits reserves and fair value derivative adjustment. 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 June 30, 2018 and December 31, 2017, derivative assets of $53 million and derivative liabilities of $24 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.

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



	Three Months Ended						Six Months Ended
	June 30						June 30
(in millions of U.S. dollars)	2018			2017			2018			2017
Investment and embedded derivative instruments:
Foreign currency forward contracts	$	3		$	(7	)	$	7		$	7
All other futures contracts and options	21			(9		)	34			(17		)
Total investment and embedded derivative instruments	$	24		$	(16	)	$	41		$	(10	)
GLB and other derivative instruments:
GLB ⁽¹⁾	$	41		$	118		$	79		$	211
Futures contracts on equities ⁽²⁾	(44		)	(38		)	(22		)	(112		)
Other	8			(1		)	10			1
Total GLB and other derivative instruments	$	5		$	79		$	67		$	100
	$	29		$	63		$	108		$	90


⁽¹⁾	Excludes foreign exchange gains (losses) related to GLB.


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

b) Derivative instrument objectives

(i) Foreign currency exposure management

A foreign currency forward contract (forward) is an agreement between participants to exchange specific foreign 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 reserves for GMDB and 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 the 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.

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. Premiums received under the reinsurance treaties are classified as premium. Expected losses allocated to premiums received are classified as Future policy benefits and valued similar to GMDB reinsurance. Other changes in fair value, principally arising from changes in expected losses allocated to expected future premiums, are classified as Net realized gains (losses). 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 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. We believe this presentation provides the most meaningful disclosure of changes in the underlying risk within the GLB reinsurance programs for a given reporting period.

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.

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 the carrying value of collateral held under securities lending agreements by investment category and remaining contractual maturity of the underlying agreements:



	Remaining contractual maturity
	June 30		December 31
	2018		2017
(in millions of U.S. dollars)	Overnight and Continuous
Collateral held under securities lending agreements:
Cash	$	990	$	828
U.S. Treasury and agency	100		36
Foreign	909		712
Corporate securities	14		—
Mortgage-backed securities	55		74
Equity securities	287		87
	$	2,355	$	1,737
Gross amount of recognized liability for securities lending payable	$	2,355	$	1,737

At June 30, 2018 and December 31, 2017, our repurchase agreement obligations of $1,413 million and $1,408 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
	June 30, 2018						December 31, 2017
	Up to 30 Days		Greater than 90 Days		Total		Up to 30 Days		Greater than 90 Days		Total
(in millions of U.S. dollars)	Up to 30 Days		Greater than 90 Days		Total		Up to 30 Days		Greater than 90 Days		Total
Collateral pledged under repurchase agreements:
U.S. Treasury and agency	$	245	$	9	$	254	$	9	$	230	$	239
Mortgage-backed securities	333		862		1,195		369		826		1,195
	$	578	$	871	$	1,449	$	378	$	1,056	$	1,434
Gross amount of recognized liabilities for repurchase agreements					$	1,413					$	1,408
Difference ⁽¹⁾					$	36					$	26


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

d) Fixed maturities

At June 30, 2018, we have commitments to purchase fixed income securities of $948 million over the next several years.

e) Other investments

At June 30, 2018, included in Other investments in the Consolidated balance sheets are investments in limited partnerships and partially-owned investment companies with a carrying value of $3.9 billion. In connection with these investments, we have commitments that may require funding of up to $3.4 billion over the next several years.

f) Taxation

At June 30, 2018, $14 million of unrecognized tax benefits remain outstanding. It is reasonably possible that over the next twelve months, the amount of unrecognized tax benefits may change resulting from the re-evaluation of unrecognized tax benefits arising from examinations by taxing authorities and the closing of tax statutes of limitations. With few exceptions, Chubb is no longer subject to state and local or non-U.S. income tax examinations for years before 2010.

g) 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.

Share-based compensation	6 Months Ended
Share-based compensation	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based compensation	Share-based compensation The Chubb Limited 2016 Long-Term Incentive Plan (the 2016 LTIP) permits grants of both incentive and non-qualified stock options principally 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 typically vest in equal annual installments over the vesting period, which is also the requisite service period. On February 22, 2018, Chubb granted 1,841,329 stock options with a weighted-average grant date fair value of $29.71 each. The fair value of the options issued is estimated on the grant date using the Black-Scholes option pricing model. The 2016 LTIP also permits grants of service-based restricted stock and restricted stock units as well as performance-based restricted stock awards. Chubb generally grants service-based restricted stock and restricted stock units with a 4-year vesting period, based on a graded vesting schedule. Beginning in 2017, the performance-based stock awards granted comprise target awards which have 3-year cliff vesting provisions based on tangible book value (shareholders' equity less goodwill and intangible assets, net of tax) per share growth and P&C combined ratio compared to a defined group of peer companies. Premium performance-based stock awards are earned only if tangible book value per share growth and the P&C combined ratio over the cumulative 3-year period after the grant of the associated target awards exceed a higher threshold compared to our peer group, with an additional vesting provision based on total shareholder return compared to our peer group. The restricted stock is granted at market close price on the grant date. On February 22, 2018, Chubb granted 973,624 service-based restricted stock awards, 301,024 service-based restricted stock units, and 180,065 performance-based stock awards to employees and officers with a grant date fair value of $143.07 each. Each restricted stock unit represents our obligation to deliver to the holder one Common Share upon vesting.

Shareholders' equity

6 Months Ended

Jun. 30, 2018

Stockholders' Equity Note [Abstract]

Shareholders' equity

Shareholders’ equity

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 consolidated financial statements. Under Swiss corporate law, dividends, including distributions through a reduction in par value (par value reduction) or from legal reserves, must be stated in Swiss francs though dividend payments are made by Chubb in U.S. dollars. At June 30, 2018, our Common Shares had a par value of CHF 24.15 per share.

At our May 2017 and 2016 annual general meetings, our shareholders approved an annual dividend for the following year of up to $2.84 per share and $2.76 per share, respectively, which were paid in four quarterly installments of $0.71 per share and $0.69 per share, respectively, at dates determined by the Board of Directors (Board) after the annual general meetings by way of a distribution from capital contribution reserves, transferred to free reserves for payment.

At our May 2018 annual general meeting, our shareholders approved an annual dividend for the following year of up to $2.92 per share, expected to be paid in four quarterly installments of $0.73 per share after the 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 2019 annual general meeting, and is authorized to abstain from distributing a dividend at its discretion.

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



	Three Months Ended						Six Months Ended
	June 30						June 30
	2018			2017			2018			2017
	CHF	USD		CHF	USD		CHF	USD		CHF	USD
Total dividend distributions per common share	0.73	$	0.73	0.69	$	0.71	1.39	$	1.44	1.38	$	1.40

Common Shares in treasury are used principally for issuance upon the exercise of employee stock options, grants of restricted stock, and purchases under the Employee Stock Purchase Plan (ESPP). At June 30, 2018, 16,281,700 Common Shares remain in treasury after net shares redeemed under employee share-based compensation plans.

Chubb Limited securities repurchase authorization

In November 2016, the Board authorized a share repurchase program of $1.0 billion of Chubb's Common Shares through December 31, 2017. In December 2017, the Board authorized a share repurchase program of $1.0 billion of Chubb's Common Shares from January 1, 2018 through December 31, 2018.

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



	Three Months Ended June 30				Six Months Ended June 30				July 1, 2018 through July 31, 2018
(in millions of U.S. dollars, except share data)	2018		2017		2018		2017		July 1, 2018 through July 31, 2018
Number of shares repurchased	2,443,855		2,381,566		2,443,855		3,417,630		740,869
Cost of shares repurchased	$	324	$	335	$	324	$	475	$	100
Repurchase authorization remaining at end of period	$	676	$	525	$	676	$	525	$	576

Postretirement benefits

6 Months Ended

Jun. 30, 2018

Retirement Benefits [Abstract]

Compensation and Employee Benefit Plans [Text Block]

Postretirement benefits

The components of net pension and other postretirement benefit costs (benefits) reflected in Net income in the Consolidated statements of operations were as follows:



	Pension Benefits												Other Postretirement Benefits
	2018						2017						2018			2017
Three Months Ended June 30	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
(in millions of U.S. dollars)	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Service cost	$	15		$	3		$	16		$	4		$	—		$	2
Interest cost	27			7			26			7			1			—
Expected return on plan assets	(53		)	(13		)	(48		)	(10		)	(1		)	(1		)
Amortization of net actuarial loss	—			—			—			1			—			—
Amortization of prior service cost	—			—			—			—			(22		)	(23		)
Curtailments	—			—			—			(8		)	(1		)	—
Settlements	1			—			—			—			—			—
Net periodic (benefit) cost	$	(10	)	$	(3	)	$	(6	)	$	(6	)	$	(23	)	$	(22	)



	Pension Benefits												Other Postretirement Benefits
	2018						2017						2018			2017
Six Months Ended June 30	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
(in millions of U.S. dollars)	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Service cost	$	29		$	6		$	32		$	8		$	—		$	2
Interest cost	53			14			52			14			2			1
Expected return on plan assets	(106		)	(26		)	(95		)	(20		)	(2		)	(2		)
Amortization of net actuarial loss	—			—			—			1			—			—
Amortization of prior service cost	—			—			—			—			(43		)	(46		)
Curtailments	—			—			—			(8		)	(1		)	—
Settlements	1			—			—			—			—			—
Net periodic (benefit) cost	$	(23	)	$	(6	)	$	(11	)	$	(5	)	$	(44	)	$	(45	)

Segment information

6 Months Ended

Jun. 30, 2018

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.

Corporate results primarily include income and expenses not attributable to reportable segments and loss and loss expenses of asbestos and environmental (A&E) liabilities.

For segment reporting purposes, certain items are presented in a different manner below than in the consolidated financial statements. Management uses underwriting income (loss) as the main measures of 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. To calculate Segment income (loss), include Net investment income, Other (income) expense, and Amortization of purchased intangibles. For the North America Agricultural Insurance segment, management includes gains and losses on crop derivatives as a component of underwriting income (loss). For example, for the three months ended June 30, 2018, underwriting income in our North America Agricultural Insurance segment was $43 million. This amount includes $8 million of realized gains related to crop derivatives which are reported in Net realized gains (losses) below.

For the Life Insurance segment, management includes Net investment income and (Gains) losses from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP as components of Life Insurance underwriting income. For example, for the three months ended June 30, 2018, Life Insurance underwriting income of $75 million includes Net investment income of $85 million and losses from fair value changes in separate account assets of $10 million. The gains (losses) from fair value changes in separate account assets are reported in Other (income) expense in the table below.

The following tables present the Statement of Operations by segment:



	North America Commercial P&C Insurance			North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance			Global Reinsurance			Life Insurance		Corporate			Chubb Consolidated
For the Three Months Ended
June 30, 2018
(in millions of U.S. dollars)
Net premiums written	$	3,331		$	1,335	$	388	$	2,199		$	197		$	565	$	—		$	8,015
Net premiums earned	3,277			1,156		351		2,161			167			552		—			7,664
Losses and loss expenses	2,084			728		289		1,071			83			184		48			4,487
Policy benefits	—			—		—		—			—			150		—			150
Policy acquisition costs	448			228		26		584			40			138		—			1,464
Administrative expenses	253			68		1		266			9			80		70			747
Underwriting income (loss)	492			132		35		240			35			—		(118		)	816
Net investment income (loss)	510			59		6		155			65			85		(52		)	828
Other (income) expense	(13		)	1		1		(12		)	(6		)	8		(94		)	(115		)
Amortization expense of purchased intangibles	—			3		7		11			—			—		64			85
Segment income (loss)	$	1,015		$	187	$	33	$	396		$	106		$	77	$	(140	)	$	1,674
Net realized gains (losses) including OTTI																18			18
Interest expense																167			167
Chubb integration expenses																13			13
Income tax expense																218			218
Net income (loss)																$	(520	)	$	1,294



	North America Commercial P&C Insurance ⁽¹⁾			North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance ⁽¹⁾			Global Reinsurance		Life Insurance			Corporate			Chubb Consolidated
For the Three Months Ended
June 30, 2017
(in millions of U.S. dollars)
Net premiums written	$	3,203		$	1,255	$	403	$	2,007		$	190	$	523		$	—		$	7,581
Net premiums earned	3,099			1,093		344		2,018			168		515			—			7,237
Losses and loss expenses	1,936			683		290		964			46		182			45			4,146
Policy benefits	—			—		—		—			—		163			—			163
Policy acquisition costs	464			230		27		555			43		130			—			1,449
Administrative expenses	241			66		2		243			12		77			65			706
Underwriting income (loss)	458			114		25		256			67		(37		)	(110		)	773
Net investment income (loss)	490			56		6		148			65		77			(72		)	770
Other (income) expense	(4		)	1		1		(3		)	1		(12		)	(129		)	(145		)
Amortization expense of purchased intangibles	—			5		7		11			—		—			42			65
Segment income (loss)	$	952		$	164	$	23	$	396		$	131	$	52		$	(95	)	$	1,623
Net realized gains (losses) including OTTI																101			101
Interest expense																147			147
Chubb integration expenses																72			72
Income tax expense																200			200
Net income (loss)																$	(413	)	$	1,305


⁽¹⁾	The 2017 net premiums written amount was revised to reflect the transfer of certain multinational accounts ($1 million) from the North America Commercial P&C Insurance segment to the Overseas General Insurance segment to better align the reporting with the management of these businesses in 2018. There is no impact on a consolidated basis.



	North America Commercial P&C Insurance			North America Personal P&C Insurance		North America Agricultural Insurance			Overseas General Insurance			Global Reinsurance			Life Insurance			Corporate			Chubb Consolidated
For the Six Months Ended
June 30, 2018
(in millions of U.S. dollars)
Net premiums written	$	6,143		$	2,383	$	496		$	4,583		$	390		$	1,124		$	—		$	15,119
Net premiums earned	6,306			2,296		394			4,268			335			1,092			—			14,691
Losses and loss expenses	3,992			1,614		236			2,149			150			389			59			8,589
Policy benefits	—			—		—			—			—			301			—			301
Policy acquisition costs	920			465		25			1,172			80			266			—			2,928
Administrative expenses	484			133		(2		)	505			19			158			142			1,439
Underwriting income (loss)	910			84		135			442			86			(22		)	(201		)	1,434
Net investment income (loss)	1,013			118		13			306			129			168			(113		)	1,634
Other (income) expense	(19		)	1		1			(5		)	(13		)	4			(131		)	(162		)
Amortization expense of purchased intangibles	—			6		14			21			—			1			128			170
Segment income (loss)	$	1,942		$	195	$	133		$	732		$	228		$	141		$	(311	)	$	3,060
Net realized gains (losses) including OTTI																		16			16
Interest expense																		324			324
Chubb integration expenses																		23			23
Income tax expense																		353			353
Net income (loss)																		$	(995	)	$	2,376



	North America Commercial P&C Insurance ⁽¹⁾		North America Personal P&C Insurance		North America Agricultural Insurance			Overseas General Insurance ⁽¹⁾			Global Reinsurance		Life Insurance			Corporate			Chubb Consolidated
For the Six Months Ended
June 30, 2017
(in millions of U.S. dollars)
Net premiums written	$	5,933	$	2,239	$	464		$	4,219		$	389	$	1,047		$	—		$	14,291
Net premiums earned	6,140		2,179		358			3,954			357		1,021			—			14,009
Losses and loss expenses	3,796		1,316		217			2,035			140		375			56			7,935
Policy benefits	—		—		—			—			—		331			—			331
Policy acquisition costs	951		447		26			1,084			94		244			—			2,846
Administrative expenses	472		131		(3		)	488			22		149			123			1,382
Underwriting income (loss)	921		285		118			347			101		(78		)	(179		)	1,515
Net investment income (loss)	968		111		12			296			127		152			(151		)	1,515
Other (income) expense	—		2		1			(4		)	1		(41		)	(174		)	(215		)
Amortization expense of purchased intangibles	—		8		14			22			—		1			84			129
Segment income (loss)	$	1,889	$	386	$	115		$	625		$	227	$	114		$	(240	)	$	3,116
Net realized gains (losses) including OTTI																94			94
Interest expense																301			301
Chubb integration expenses																183			183
Income tax expense																328			328
Net income (loss)																$	(958	)	$	2,398


⁽¹⁾	The 2017 net premiums written amount was revised to reflect the transfer of certain multinational accounts ($13 million) from the North America Commercial P&C Insurance segment to the Overseas General Insurance segment to better align the reporting with the management of these businesses in 2018. There is no impact on a consolidated basis.

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

Earnings per share

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Earnings per share



	Three Months Ended				Six Months Ended
	June 30				June 30
(in millions of U.S. dollars, except share and per share data)	2018		2017		2018		2017
Numerator:
Net income	$	1,294	$	1,305	$	2,376	$	2,398
Denominator:
Denominator for basic earnings per share:
Weighted-average shares outstanding	465,276,597		467,981,077		465,488,724		468,244,458
Denominator for diluted earnings per share:
Share-based compensation plans	3,103,727		3,872,860		3,489,013		3,900,678
Weighted-average shares outstanding and assumed conversions	468,380,324		471,853,937		468,977,737		472,145,136
Basic earnings per share	$	2.78	$	2.79	$	5.10	$	5.12
Diluted earnings per share	$	2.76	$	2.77	$	5.07	$	5.08
Potential anti-dilutive share conversions	3,814,491		2,066,578		3,305,735		1,467,556

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

Information provided in connection with outstanding debt of subsidiaries

6 Months Ended

Jun. 30, 2018

Disclosure Text Block Supplement [Abstract]

Information provided in connection with outstanding debt of subsidiaries

The following tables present condensed consolidating financial information at June 30, 2018 and December 31, 2017, and for the three and six months ended June 30, 2018 and 2017 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 June 30, 2018



(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	$	—	$	172	$	101,014	$	—		$	101,186
Cash ⁽¹⁾	1		1		2,238		(1,240		)	1,000
Restricted cash	—		—		101		—			101
Insurance and reinsurance balances receivable	—		—		11,297		(956		)	10,341
Reinsurance recoverable on losses and loss expenses	—		—		27,117		(12,325		)	14,792
Reinsurance recoverable on policy benefits	—		—		1,127		(923		)	204
Value of business acquired	—		—		311		—			311
Goodwill and other intangible assets	—		—		21,759		—			21,759
Investments in subsidiaries	42,919		51,706		—		(94,625		)	—
Due from subsidiaries and affiliates, net	8,686		—		257		(8,943		)	—
Other assets	2		655		18,760		(1,577		)	17,840
Total assets	$	51,608	$	52,534	$	183,981	$	(120,589	)	$	167,534
Liabilities
Unpaid losses and loss expenses	$	—	$	—	$	73,427	$	(10,649	)	$	62,778
Unearned premiums	—		—		16,815		(1,067		)	15,748
Future policy benefits	—		—		6,393		(923		)	5,470
Due to subsidiaries and affiliates, net	—		8,943		—		(8,943		)	—
Affiliated notional cash pooling programs ⁽¹⁾	403		837		—		(1,240		)	—
Repurchase agreements	—		—		1,413		—			1,413
Short-term debt	—		600		—		—			600
Long-term debt	—		12,173		11		—			12,184
Trust preferred securities	—		308		—		—			308
Other liabilities	234		2,248		18,722		(3,142		)	18,062
Total liabilities	637		25,109		116,781		(25,964		)	116,563
Total shareholders’ equity	50,971		27,425		67,200		(94,625		)	50,971
Total liabilities and shareholders’ equity	$	51,608	$	52,534	$	183,981	$	(120,589	)	$	167,534

⁽¹⁾

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Balance Sheet at December 31, 2017



(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	$	—	$	168	$	102,276	$	—		$	102,444
Cash ⁽¹⁾	3		1		839		(115		)	728
Restricted cash	—		—		123		—			123
Insurance and reinsurance balances receivable	—		—		10,820		(1,486		)	9,334
Reinsurance recoverable on losses and loss expenses	—		—		27,514		(12,480		)	15,034
Reinsurance recoverable on policy benefits	—		—		1,194		(1,010		)	184
Value of business acquired	—		—		326		—			326
Goodwill and other intangible assets	—		—		22,054		—			22,054
Investments in subsidiaries	41,909		51,165		—		(93,074		)	—
Due from subsidiaries and affiliates, net	9,639		—		—		(9,639		)	—
Other assets	3		287		20,578		(4,073		)	16,795
Total assets	$	51,554	$	51,621	$	185,724	$	(121,877	)	$	167,022
Liabilities
Unpaid losses and loss expenses	$	—	$	—	$	74,767	$	(11,588	)	$	63,179
Unearned premiums	—		—		18,875		(3,659		)	15,216
Future policy benefits	—		—		6,331		(1,010		)	5,321
Due to subsidiaries and affiliates, net	—		9,432		207		(9,639		)	—
Affiliated notional cash pooling programs ⁽¹⁾	—		115		—		(115		)	—
Repurchase agreements	—		—		1,408		—			1,408
Short-term debt	—		1,013		—		—			1,013
Long-term debt	—		11,546		10		—			11,556
Trust preferred securities	—		308		—		—			308
Other liabilities	382		1,411		18,848		(2,792		)	17,849
Total liabilities	382		23,825		120,446		(28,803		)	115,850
Total shareholders’ equity	51,172		27,796		65,278		(93,074		)	51,172
Total liabilities and shareholders’ equity	$	51,554	$	51,621	$	185,724	$	(121,877	)	$	167,022

⁽¹⁾

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Statements of Operations and Comprehensive Income



For the Three Months Ended June 30, 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)	Chubb Limited (Parent Guarantor)			Chubb INA Holdings Inc. (Subsidiary Issuer)			Other Chubb Limited Subsidiaries			Consolidating Adjustments and Eliminations			Chubb Limited Consolidated
Net premiums written	$	—		$	—		$	8,015		$	—		$	8,015
Net premiums earned	—			—			7,664			—			7,664
Net investment income	1			5			822			—			828
Equity in earnings of subsidiaries	1,241			454			—			(1,695		)	—
Net realized gains (losses) including OTTI	2			73			(57		)	—			18
Losses and loss expenses	—			—			4,487			—			4,487
Policy benefits	—			—			150			—			150
Policy acquisition costs and administrative expenses	23			19			2,169			—			2,211
Interest (income) expense	(76		)	204			39			—			167
Other (income) expense	(4		)	8			(119		)	—			(115		)
Amortization of purchased intangibles	—			—			85			—			85
Chubb integration expenses	2			—			11			—			13
Income tax expense (benefit)	5			(36		)	249			—			218
Net income	$	1,294		$	337		$	1,358		$	(1,695	)	$	1,294
Comprehensive income (loss)	$	277		$	(462	)	$	352		$	110		$	277

Condensed Consolidating Statements of Operations and Comprehensive Income



For the Three Months Ended June 30, 2017	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)	Chubb Limited (Parent Guarantor)			Chubb INA Holdings Inc. (Subsidiary Issuer)			Other Chubb Limited Subsidiaries			Consolidating Adjustments and Eliminations			Chubb Limited Consolidated
Net premiums written	$	—		$	—		$	7,581		$	—		$	7,581
Net premiums earned	—			—			7,237			—			7,237
Net investment income	2			4			764			—			770
Equity in earnings of subsidiaries	1,253			665			—			(1,918		)	—
Net realized gains (losses) including OTTI	(2		)	(1		)	104			—			101
Losses and loss expenses	—			—			4,146			—			4,146
Policy benefits	—			—			163			—			163
Policy acquisition costs and administrative expenses	18			(2		)	2,139			—			2,155
Interest (income) expense	(84		)	212			19			—			147
Other (income) expense	4			10			(159		)	—			(145		)
Amortization of purchased intangibles	—			—			65			—			65
Chubb integration expenses	6			4			62			—			72
Income tax expense (benefit)	4			(87		)	283			—			200
Net income	$	1,305		$	531		$	1,387		$	(1,918	)	$	1,305
Comprehensive income	$	1,675		$	920		$	1,756		$	(2,676	)	$	1,675

Condensed Consolidating Statements of Operations and Comprehensive Income



For the Six Months Ended June 30, 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)	Chubb Limited (Parent Guarantor)			Chubb INA Holdings Inc. (Subsidiary Issuer)			Other Chubb Limited Subsidiaries			Consolidating Adjustments and Eliminations			Chubb Limited Consolidated
Net premiums written	$	—		$	—		$	15,119		$	—		$	15,119
Net premiums earned	—			—			14,691			—			14,691
Net investment income	3			9			1,622			—			1,634
Equity in earnings of subsidiaries	2,263			1,339			—			(3,602		)	—
Net realized gains (losses) including OTTI	—			49			(33		)	—			16
Losses and loss expenses	—			—			8,589			—			8,589
Policy benefits	—			—			301			—			301
Policy acquisition costs and administrative expenses	41			41			4,285			—			4,367
Interest (income) expense	(156		)	413			67			—			324
Other (income) expense	(9		)	16			(169		)	—			(162		)
Amortization of purchased intangibles	—			—			170			—			170
Chubb integration expenses	4			1			18			—			23
Income tax expense (benefit)	10			(95		)	438			—			353
Net income	$	2,376		$	1,021		$	2,581		$	(3,602	)	$	2,376
Comprehensive income (loss)	$	730		$	(246	)	$	966		$	(720	)	$	730

Condensed Consolidating Statements of Operations and Comprehensive Income



For the Six Months Ended June 30, 2017	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)	Chubb Limited (Parent Guarantor)			Chubb INA Holdings Inc. (Subsidiary Issuer)			Other Chubb Limited Subsidiaries			Consolidating Adjustments and Eliminations			Chubb Limited Consolidated
Net premiums written	$	—		$	—		$	14,291		$	—		$	14,291
Net premiums earned	—			—			14,009			—			14,009
Net investment income	2			7			1,506			—			1,515
Equity in earnings of subsidiaries	2,280			1,366			—			(3,646		)	—
Net realized gains (losses) including OTTI	(2		)	(14		)	110			—			94
Losses and loss expenses	—			—			7,935			—			7,935
Policy benefits	—			—			331			—			331
Policy acquisition costs and administrative expenses	36			12			4,180			—			4,228
Interest (income) expense	(168		)	433			36			—			301
Other (income) expense	(2		)	25			(238		)	—			(215		)
Amortization of purchased intangibles	—			—			129			—			129
Chubb integration expenses	6			53			124			—			183
Income tax expense (benefit)	10			(199		)	517			—			328
Net income	$	2,398		$	1,035		$	2,611		$	(3,646	)	$	2,398
Comprehensive income	$	3,082		$	1,711		$	3,294		$	(5,005	)	$	3,082

Condensed Consolidating Statement of Cash Flows



For the Six Months Ended June 30, 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	$	43		$	3,042		$	2,187		$	(3,075	)	$	2,197
Cash flows from investing activities
Purchases of fixed maturities available for sale	—			(22		)	(12,275		)	—			(12,297		)
Purchases of fixed maturities held to maturity	—			—			(337		)	—			(337		)
Purchases of equity securities	—			—			(85		)	—			(85		)
Sales of fixed maturities available for sale	—			—			6,858			—			6,858
Sales of equity securities	—			—			83			—			83
Maturities and redemptions of fixed maturities available for sale	—			14			3,906			—			3,920
Maturities and redemptions of fixed maturities held to maturity	—			—			732			—			732
Net change in short-term investments	—			6			395			—			401
Net derivative instruments settlements	—			(8		)	13			—			5
Private equity contributions	—			—			(813		)	—			(813		)
Private equity distributions	—			—			413			—			413
Capital contribution	(750		)	(3,500		)	—			4,250			—
Other	—			(7		)	(133		)	—			(140		)
Net cash flows used for investing activities	(750		)	(3,517		)	(1,243		)	4,250			(1,260		)
Cash flows from financing activities
Dividends paid on Common Shares	(661		)	—			—			—			(661		)
Common Shares repurchased	—			—			(347		)	—			(347		)
Proceeds from issuance of long-term debt	—			2,171			—			—			2,171
Repayment of long-term debt	—			(1,900		)	—			—			(1,900		)
Proceeds from issuance of repurchase agreements	—			—			1,014			—			1,014
Repayment of repurchase agreements	—			—			(1,009		)	—			(1,009		)
Proceeds from share-based compensation plans	—			—			60			—			60
Dividend to parent company	—			—			(3,075		)	3,075			—
Advances (to) from affiliates	963			(518		)	(445		)	—			—
Capital contribution	—			—			4,250			(4,250		)	—
Net proceeds from (payments to) affiliated notional cash pooling programs⁽¹⁾	403			722			—			(1,125		)	—
Policyholder contract deposits	—			—			192			—			192
Policyholder contract withdrawals	—			—			(169		)	—			(169		)
Net cash flows from (used for) financing activities	705			475			471			(2,300		)	(649		)
Effect of foreign currency rate changes on cash and restricted cash	—			—			(38		)	—			(38		)
Net increase (decrease) in cash and restricted cash	(2		)	—			1,377			(1,125		)	250
Cash and restricted cash – beginning of period⁽¹⁾	3			1			962			(115		)	851
Cash and restricted cash – end of period⁽¹⁾	$	1		$	1		$	2,339		$	(1,240	)	$	1,101

⁽¹⁾

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2018 and December 31, 2017, 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 Six Months Ended June 30, 2017	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 (used for) operating activities	$	551		$	1,444		$	1,686		$	(2,041	)	$	1,640
Cash flows from investing activities
Purchases of fixed maturities available for sale	—			(5		)	(12,255		)	—			(12,260		)
Purchases of fixed maturities held to maturity	—			—			(212		)	—			(212		)
Purchases of equity securities	—			—			(82		)	—			(82		)
Sales of fixed maturities available for sale	—			—			6,873			—			6,873
Sales of equity securities	—			—			104			—			104
Maturities and redemptions of fixed maturities available for sale	—			13			5,156			—			5,169
Maturities and redemptions of fixed maturities held to maturity	—			—			408			—			408
Net change in short-term investments	—			166			188			—			354
Net derivative instruments settlements	—			(7		)	(122		)	—			(129		)
Private equity contributions	—			—			(345		)	—			(345		)
Private equity distributions	—			—			487			—			487
Other	—			2			(246		)	—			(244		)
Net cash flows from (used for) investing activities	—			169			(46		)	—			123
Cash flows from financing activities
Dividends paid on Common Shares	(646		)	—			—			—			(646		)
Common Shares repurchased	—			—			(475		)	—			(475		)
Repayment of long-term debt	—			(500		)	—			—			(500		)
Proceeds from issuance of repurchase agreements	—			—			1,343			—			1,343
Repayment of repurchase agreements	—			—			(1,338		)	—			(1,338		)
Proceeds from share-based compensation plans	—			—			89			—			89
Dividend to parent company	—			—			(2,041		)	2,041			—
Advances (to) from affiliates	264			(328		)	64			—			—
Net proceeds from affiliated notional cash pooling programs⁽¹⁾	(170		)	(619		)	—			789			—
Policyholder contract deposits	—			—			209			—			209
Policyholder contract withdrawals	—			—			(125		)	—			(125		)
Net cash flows used for financing activities	(552		)	(1,447		)	(2,274		)	2,830			(1,443		)
Effect of foreign currency rate changes on cash and restricted cash	—			—			11			—			11
Net increase (decrease) in cash and restricted cash	(1		)	166			(623		)	789			331
Cash and restricted cash – beginning of period⁽¹⁾	1			1			2,068			(982		)	1,088
Cash and restricted cash – end of period⁽¹⁾	$	—		$	167		$	1,445		$	(193	)	$	1,419

⁽¹⁾

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2017 and December 31, 2016, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

General (Policies)

6 Months Ended

Jun. 30, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of presentation

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. Chubb operates 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 10 for additional information.

The interim unaudited 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 (consisting of normally recurring accruals) 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 results of operations and cash flows for any interim period are not necessarily indicative of the results for the full year. These consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in our 2017 Form 10-K.

Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]

b) Restricted cash

Effective January 1, 2018, we retrospectively adopted guidance on "Restricted Cash" that clarified the presentation of restricted cash on the consolidated statement of cash flows. As a result, we revised the statement of cash flows for the six months ended June 30, 2017 to include restricted cash in the beginning and ending cash balances. In addition, we reclassified $123 million of Restricted cash from Other assets to a separate line in the balance sheet as of December 31, 2017.

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:



	June 30		December 31
(in millions of U.S. dollars)	2018		2017
Cash	$	1,000	$	728
Restricted cash	101		123
Total cash and restricted cash shown in the consolidated statements of cash flows	$	1,101	$	851

Accounting guidance adopted in 2018

d) Accounting guidance adopted in 2018

Revenue from Contracts with Customers

In May 2014, the FASB issued an accounting standard that supersedes most existing revenue recognition guidance. The standard excludes from its scope the accounting for insurance contracts, leases, financial instruments, and certain other agreements that are governed under other GAAP guidance, but could affect the revenue recognition for certain of our claims management and risk control services. The updated guidance requires an entity to recognize revenue as performance obligations are met, in order to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration the entity is entitled to receive for those goods or services. This guidance was effective for us on January 1, 2018. The adoption of this guidance did not have a material impact on our financial condition or results of operations given that the majority of our business is outside the scope of this guidance.

Financial Instruments – Recognition and Measurement of Financial Assets and Financial Liabilities

Effective January 2018, we adopted new accounting guidance on "Recognition and Measurement of Financial Assets and Financial Liabilities" on a modified-retrospective basis. The guidance requires equity investments, other than those accounted for under the equity method of accounting, to be measured at fair value with changes in fair value recognized through net income. The guidance impacts our public equities and cost-method private equities. As a result, we recorded a cumulative-effect adjustment to increase beginning Retained earnings by $417 million after tax ($454 million pre-tax), representing the unrealized appreciation on our equity investments with an offsetting adjustment to decrease Accumulated other comprehensive income. All subsequent changes in fair value of our equity investments are recognized within realized gains (losses) on the consolidated statement of operations. Prior period amounts have not been adjusted and continue to be reported in accordance with the previous accounting guidance.

Income Taxes

Effective January 2018, we adopted new accounting guidance on “Intra-Entity Transfers of Assets Other Than Inventory” on a modified-retrospective basis. Under the new guidance, we will no longer defer taxes on intra-company asset transfers and will recognize any related income tax expense (benefit) immediately through the consolidated statement of operations. As a result, we recorded a cumulative-effect adjustment to decrease beginning Retained earnings by $7 million representing the removal of the deferred tax asset for previous intra-company asset transfer transactions not yet recognized through earnings.

Income Tax Accounting Implications of the Tax Cuts and Jobs Act

The Tax Cuts and Jobs Act (2017 Tax Act) was signed into legislation in December 2017. The Securities and Exchange Commission issued Staff Accounting Bulletin No. 118 (SAB 118), Income Tax Accounting Implications of the Tax Cuts and Jobs Act, which provides guidance for the application of the 2017 Tax Act. The income tax guidance allows for the transition impact of the 2017 Tax Act to be recorded as 1) complete with all accounting implications identified, 2) provisional based on a reasonable estimate, or 3) not recorded as no reasonable estimate was determinable.

In December 2017, we recorded a $450 million income tax benefit which was our estimate of the tax effects of the 2017 Tax Act. This amount was recorded as provisional under SAB 118. There were no changes determined to this estimate for the current period as we continue to analyze the impact of the 2017 Tax Act. We will continue to monitor this area as new regulations and interpretive guidance are released and will update as appropriate.

Accounting guidance not yet adopted

Refer to the 2017 Form 10-K for information on other accounting guidance not yet adopted.

Fair value measurements Fair Value Measurement Policy (Policies)

6 Months Ended

Jun. 30, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurement, Policy [Policy Text Block]

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.

General General (Tables)

6 Months Ended

Jun. 30, 2018

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:



	June 30		December 31
(in millions of U.S. dollars)	2018		2017
Cash	$	1,000	$	728
Restricted cash	101		123
Total cash and restricted cash shown in the consolidated statements of cash flows	$	1,101	$	851

Investments (Tables)

6 Months Ended

Jun. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule Of Amortized Cost And Fair Value Of HTM Fixed Maturities And Related OTTI Recognized In AOCI



June 30, 2018	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
(in millions of U.S. dollars)	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
Available for sale
U.S. Treasury and agency	$	3,827	$	18	$	(81	)	$	3,764	$	—
Foreign	21,884		421		(294		)	22,011		—
Corporate securities	24,665		235		(415		)	24,485		(4		)
Mortgage-backed securities	15,853		40		(410		)	15,483		(1		)
States, municipalities, and political subdivisions	12,317		55		(152		)	12,220		—
	$	78,546	$	769	$	(1,352	)	$	77,963	$	(5	)
Held to maturity
U.S. Treasury and agency	$	1,143	$	9	$	(19	)	$	1,133	$	—
Foreign	1,678		14		(17		)	1,675		—
Corporate securities	2,736		14		(85		)	2,665		—
Mortgage-backed securities	2,640		7		(62		)	2,585		—
States, municipalities, and political subdivisions	5,663		16		(72		)	5,607		—
	$	13,860	$	60	$	(255	)	$	13,665	$	—



December 31, 2017	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
(in millions of U.S. dollars)	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
Available for sale
U.S. Treasury and agency	$	3,701	$	32	$	(35	)	$	3,698	$	—
Foreign	20,514		622		(106		)	21,030		(1		)
Corporate securities	23,453		638		(95		)	23,996		(4		)
Mortgage-backed securities	15,279		111		(100		)	15,290		(1		)
States, municipalities, and political subdivisions	14,888		125		(88		)	14,925		—
	$	77,835	$	1,528	$	(424	)	$	78,939	$	(6	)
Held to maturity
U.S. Treasury and agency	$	908	$	12	$	(5	)	$	915	$	—
Foreign	1,738		27		(8		)	1,757		—
Corporate securities	3,159		67		(7		)	3,219		—
Mortgage-backed securities	2,724		23		(5		)	2,742		—
States, municipalities, and political subdivisions	5,806		50		(15		)	5,841		—
	$	14,335	$	179	$	(40	)	$	14,474	$	—

Schedule Of Amortized Cost and Fair Value of Available-for-sale Securities and Related OTTI Recognized in AOCI



June 30, 2018	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
(in millions of U.S. dollars)	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
Available for sale
U.S. Treasury and agency	$	3,827	$	18	$	(81	)	$	3,764	$	—
Foreign	21,884		421		(294		)	22,011		—
Corporate securities	24,665		235		(415		)	24,485		(4		)
Mortgage-backed securities	15,853		40		(410		)	15,483		(1		)
States, municipalities, and political subdivisions	12,317		55		(152		)	12,220		—
	$	78,546	$	769	$	(1,352	)	$	77,963	$	(5	)
Held to maturity
U.S. Treasury and agency	$	1,143	$	9	$	(19	)	$	1,133	$	—
Foreign	1,678		14		(17		)	1,675		—
Corporate securities	2,736		14		(85		)	2,665		—
Mortgage-backed securities	2,640		7		(62		)	2,585		—
States, municipalities, and political subdivisions	5,663		16		(72		)	5,607		—
	$	13,860	$	60	$	(255	)	$	13,665	$	—



December 31, 2017	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
(in millions of U.S. dollars)	Amortized Cost		Gross Unrealized Appreciation		Gross Unrealized Depreciation			Fair Value		OTTI Recognized in AOCI
Available for sale
U.S. Treasury and agency	$	3,701	$	32	$	(35	)	$	3,698	$	—
Foreign	20,514		622		(106		)	21,030		(1		)
Corporate securities	23,453		638		(95		)	23,996		(4		)
Mortgage-backed securities	15,279		111		(100		)	15,290		(1		)
States, municipalities, and political subdivisions	14,888		125		(88		)	14,925		—
	$	77,835	$	1,528	$	(424	)	$	78,939	$	(6	)
Held to maturity
U.S. Treasury and agency	$	908	$	12	$	(5	)	$	915	$	—
Foreign	1,738		27		(8		)	1,757		—
Corporate securities	3,159		67		(7		)	3,219		—
Mortgage-backed securities	2,724		23		(5		)	2,742		—
States, municipalities, and political subdivisions	5,806		50		(15		)	5,841		—
	$	14,335	$	179	$	(40	)	$	14,474	$	—

Schedule Of Fixed Maturities By Contractual Maturity

The following table presents fixed maturities by contractual maturity:



			June 30				December 31
			2018				2017
(in millions of U.S. dollars)	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Available for sale
Due in 1 year or less	$	3,801	$	3,808	$	3,164	$	3,182
Due after 1 year through 5 years	26,591		26,583		24,749		25,068
Due after 5 years through 10 years	24,016		23,695		25,388		25,704
Due after 10 years	8,285		8,394		9,255		9,695
	62,693		62,480		62,556		63,649
Mortgage-backed securities	15,853		15,483		15,279		15,290
	$	78,546	$	77,963	$	77,835	$	78,939
Held to maturity
Due in 1 year or less	$	644	$	645	$	743	$	746
Due after 1 year through 5 years	2,783		2,767		2,669		2,688
Due after 5 years through 10 years	4,634		4,554		4,744		4,756
Due after 10 years	3,159		3,114		3,455		3,542
	11,220		11,080		11,611		11,732
Mortgage-backed securities	2,640		2,585		2,724		2,742
	$	13,860	$	13,665	$	14,335	$	14,474

Schedule of Realized Gain (Loss)

The following table presents the components of Net realized gains (losses):



	Three Months Ended						Six Months Ended
	June 30						June 30
(in millions of U.S. dollars)	2018			2017			2018			2017
Fixed maturities:
OTTI on fixed maturities, gross	$	(4	)	$	(5	)	$	(5	)	$	(11	)
OTTI on fixed maturities recognized in OCI (pre-tax)	—			1			—			1
OTTI on fixed maturities, net	(4		)	(4		)	(5		)	(10		)
Gross realized gains excluding OTTI	99			45			165			79
Gross realized losses excluding OTTI	(176		)	(18		)	(264		)	(58		)
Total fixed maturities	(81		)	23			(104		)	11
Equity securities:
OTTI on equity securities	—			(3		)	—			(8		)
Gross realized gains excluding OTTI	6			6			16			15
Gross realized losses excluding OTTI	(8		)	(1		)	(29		)	(1		)
Total equity securities	(2		)	2			(13		)	6
OTTI on other investments	—			(1		)	—			(9		)
Other investments	(11		)	—			18			—
Foreign exchange gains (losses)	140			14			63			(5		)
Investment and embedded derivative instruments	24			(16		)	41			(10		)
Fair value adjustments on insurance derivative	41			118			79			211
S&P put options and futures	(44		)	(38		)	(22		)	(112		)
Other derivative instruments	8			(1		)	10			1
Other	(57		)	—			(56		)	1
Net realized gains (losses)	$	18		$	101		$	16		$	94

Schedule Of Roll-Forward Of Pre-Tax Credit Losses Related To Fixed Maturities For Which A Portion Of OTTI Was Recognized In OCI

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:



	Three Months Ended					Six Months Ended
	June 30					June 30
(in millions of U.S. dollars)	2018		2017			2018			2017
Balance of credit losses related to securities still held – beginning of period	$	15	$	32		$	22		$	35
Additions where no OTTI was previously recorded	1		1			1			1
Additions where an OTTI was previously recorded	—		—			—			1
Reductions for securities sold during the period	—		(4		)	(7		)	(8		)
Balance of credit losses related to securities still held – end of period	$	16	$	29		$	16		$	29

Gain (Loss) on Investments [Table Text Block]

Effective January 1, 2018, we adopted new accounting guidance that requires any changes in fair value of equity securities and other investments that are accounted for under the cost-method to be recognized immediately in realized gains and losses in net income. As a result, beginning on January 1, 2018, realized gains and losses from these investments include both sales of securities and unrealized gains and losses as follows:



	Three Months Ended									Six Months Ended
	June 30, 2018									June 30, 2018
(in millions of U.S. dollars)	Equity Securities			Other Investments			Total			Equity Securities			Other Investments		Total
Net gains (losses) recognized during the period	$	(2	)	$	(11	)	$	(13	)	$	(13	)	$	18	$	5
Less: Net gains (losses) recognized from sales of securities	5			—			5			15			—		15
Unrealized gains (losses) recognized for securities still held at reporting date	$	(7	)	$	(11	)	$	(18	)	$	(28	)	$	18	$	(10	)

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 tables present, 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
June 30, 2018	Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)	Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss
U.S. Treasury and agency	$	2,952	$	(59	)	$	1,275	$	(41	)	$	4,227	$	(100	)
Foreign	8,886		(219		)	3,127		(92		)	12,013		(311		)
Corporate securities	15,899		(411		)	1,553		(89		)	17,452		(500		)
Mortgage-backed securities	12,438		(325		)	2,892		(147		)	15,330		(472		)
States, municipalities, and political subdivisions	13,551		(177		)	1,230		(47		)	14,781		(224		)
Total fixed maturities	$	53,726	$	(1,191	)	$	10,077	$	(416	)	$	63,803	$	(1,607	)



	0 – 12 Months					Over 12 Months					Total
December 31, 2017	Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)	Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss			Fair Value		Gross Unrealized Loss
U.S. Treasury and agency	$	2,172	$	(14	)	$	1,249	$	(26	)	$	3,421	$	(40	)
Foreign	5,657		(65		)	1,693		(49		)	7,350		(114		)
Corporate securities	5,210		(56		)	1,332		(46		)	6,542		(102		)
Mortgage-backed securities	6,194		(31		)	3,209		(74		)	9,403		(105		)
States, municipalities, and political subdivisions	9,259		(71		)	1,402		(32		)	10,661		(103		)
Total fixed maturities	28,492		(237		)	8,885		(227		)	37,377		(464		)
Equity securities	115		(12		)	—		—			115		(12		)
Other investments	78		(8		)	—		—			78		(8		)
Total	$	28,685	$	(257	)	$	8,885	$	(227	)	$	37,570	$	(484	)

Schedule Of Components Of Restricted Assets

The following table presents the components of restricted assets:



	June 30		December 31
(in millions of U.S. dollars)	2018		2017
Trust funds	$	14,775	$	17,011
Deposits with U.S. regulatory authorities	2,460		2,345
Deposits with non-U.S. regulatory authorities	2,206		2,250
Assets pledged under repurchase agreements	1,449		1,434
Other pledged assets	407		414
	$	21,297	$	23,454

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

Tabular disclosure of the realized and unrealized gains and losses reported in the statement of income which have resulted from the sale and holding of marketable securities, respectively, as well as the sale or disposal of cost method investments. Such amounts would include realized gains and losses on the sale or disposal of trading, available-for-sale, and held-to-maturity securities, unrealized gains and losses on trading securities, unrealized gains and losses on available-for-sale and held-to-maturity securities transferred to the trading securities category, realized gains and losses on the sale or disposal of cost method investments, and losses recognized for other than temporary impairments (OTTI) of such investments.

Tabular disclosure of all investments in certain debt and equity securities for which the entity has the positive intent and ability to hold until maturity.

Financial Instruments Measured At Fair Value On A Recurring Basis

Fair value measurements (Tables)

6 Months Ended

Jun. 30, 2018

Fair Value Disclosures [Abstract]

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



June 30, 2018	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities available for sale
U.S. Treasury and agency	$	2,939	$	825	$	—	$	3,764
Foreign	—		21,759		252		22,011
Corporate securities	—		23,304		1,181		24,485
Mortgage-backed securities	—		15,401		82		15,483
States, municipalities, and political subdivisions	—		12,220		—		12,220
	2,939		73,509		1,515		77,963
Equity securities	874		—		59		933
Short-term investments	1,750		1,409		12		3,171
Other investments ⁽¹⁾	424		326		264		1,014
Securities lending collateral	—		2,355		—		2,355
Investment derivative instruments	39		—		—		39
Other derivative instruments	50		—		—		50
Separate account assets	2,862		116		—		2,978
Total assets measured at fair value ⁽¹⁾	$	8,938	$	77,715	$	1,850	$	88,503
Liabilities:
Investment derivative instruments	$	42	$	—	$	—	$	42
Other derivative instruments	—		—		2		2
GLB ⁽²⁾	—		—		125		125
Total liabilities measured at fair value	$	42	$	—	$	127	$	169


⁽¹⁾	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,224 million and other investments of $21 million at June 30, 2018 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. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.



December 31, 2017	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities available for sale
U.S. Treasury and agency	$	3,129	$	569	$	—	$	3,698
Foreign	—		20,937		93		21,030
Corporate securities	—		22,959		1,037		23,996
Mortgage-backed securities	—		15,212		78		15,290
States, municipalities, and political subdivisions	—		14,925		—		14,925
	3,129		74,602		1,208		78,939
Equity securities	893		—		44		937
Short-term investments	2,309		1,252		—		3,561
Other investments ⁽¹⁾	466		305		263		1,034
Securities lending collateral	—		1,737		—		1,737
Investment derivative instruments	18		—		—		18
Other derivative instruments	1		—		—		1
Separate account assets	2,635		99		—		2,734
Total assets measured at fair value ⁽¹⁾	$	9,451	$	77,995	$	1,515	$	88,961
Liabilities:
Investment derivative instruments	$	30	$	—	$	—	$	30
Other derivative instruments	21		—		2		23
GLB ⁽²⁾	—		—		204		204
Total liabilities measured at fair value	$	51	$	—	$	206	$	257


⁽¹⁾	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $3,623 million and other investments of $15 million at December 31, 2017 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. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.

Fair Value And Maximum Future Funding Commitments Related To Investments

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



				June 30				December 31
	Expected Liquidation Period of Underlying Assets			2018				2017
(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	5 to 9 Years	$	569	$	281	$	540	$	330
Real Assets	3 to 7 Years	673		192		651		114
Distressed	3 to 7 Years	279		131		289		141
Private Credit	3 to 7 Years	184		308		187		327
Traditional	3 to 15 Years	2,177		2,529		1,656		3,149
Vintage	1 to 2 Years	64		—		30		—
Investment funds	Not Applicable	278		—		270		—
		$	4,224	$	3,441	$	3,623	$	4,061

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.

(in millions of U.S. dollars, except for percentages)

Fair Value

Valuation

Technique

Significant

Unobservable Inputs

Ranges

June 30, 2018

December 31, 2017

GLB ⁽¹⁾

$

125

$

204

Actuarial model

Lapse rate

3% – 33%

Annuitization rate

0% – 100%


⁽¹⁾	Discussion of the most significant inputs used in the fair value measurement of GLB and the sensitivity of those assumptions is included within Note 3 a) Guaranteed living benefits.

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

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
Three Months Ended	Available-for-Sale Debt Securities									Equity securities			Short-term investments			Other investments			Other derivative instruments		GLB ⁽²⁾
June 30, 2018	Foreign			Corporate securities ⁽¹⁾			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities ⁽¹⁾			MBS
Balance – beginning of period	$	176		$	1,073		$	83		$	64		$	12		$	270		$	2	$	167
Transfers into Level 3	—			6			—			—			—			—			—		—
Transfers out of Level 3	—			—			—			—			—			—			—		—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	(7		)	(9		)	—			—			—			—			—		—
Net Realized Gains/Losses	—			2			—			(3		)	—			1			—		(42		)
Purchases	95			217			—			3			1			16			—		—
Sales	(11		)	(45		)	—			(5		)	—			—			—		—
Settlements	(1		)	(63		)	(1		)	—			(1		)	(23		)	—		—
Balance – end of period	$	252		$	1,181		$	82		$	59		$	12		$	264		$	2	$	125
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—		$	(3	)	$	—		$	1		$	—	$	(42	)


⁽¹⁾	Purchases in Level 3 primarily consist of privately-placed fixed income securities.

⁽²⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $529 million at March 31, 2018, which includes a fair value derivative adjustment of $125 million and $167 million, respectively.



	Assets																				Liabilities
Three Months Ended	Available-for-Sale Debt Securities								Equity securities			Short-term investments			Other investments			Other derivative instruments			GLB ⁽¹⁾
June 30, 2017	Foreign			Corporate securities			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities			MBS
Balance – beginning of period	$	80		$	737		$	45	$	41		$	21		$	233		$	11		$	466
Transfers into Level 3	—			28			—		—			—			—			—			9
Transfers out of Level 3	—			(13		)	—		—			—			—			(9		)	—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	3			—			—		1			—			(1		)	—			—
Net Realized Gains/Losses	2			—			—		—			—			—			—			(118		)
Purchases	19			65			—		6			7			16			—			—
Sales	(19		)	(28		)	—		(9		)	—			—			—			—
Settlements	—			(42		)	—		—			(21		)	(5		)	—			—
Balance – end of period	$	85		$	747		$	45	$	39		$	7		$	243		$	2		$	357
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—	$	—		$	—		$	—		$	—		$	(118	)

⁽¹⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $774 million at March 31, 2017, which includes a fair value derivative adjustment of $357 million and $466 million, respectively.



	Assets																		Liabilities
Six Months Ended	Available-for-Sale Debt Securities									Equity securities			Short-term investments			Other investments			Other derivative instruments		GLB⁽²⁾
June 30, 2018	Foreign			Corporate securities ⁽¹⁾			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities ⁽¹⁾			MBS
Balance – beginning of period	$	93		$	1,037		$	78		$	44		$	—		$	263		$	2	$	204
Transfers into Level 3	7			6			1			—			5			—			—		—
Transfers out of Level 3	—			(10		)	—			—			—			—			—		—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	2			(12		)	—			1			—			2			—		—
Net Realized Gains/Losses	—			2			—			(1		)	—			1			—		(79		)
Purchases	182			356			4			20			9			30			—		—
Sales	(30		)	(96		)	—			(5		)	—			—			—		—
Settlements	(2		)	(102		)	(1		)	—			(2		)	(32		)	—		—
Balance – end of period	$	252		$	1,181		$	82		$	59		$	12		$	264		$	2	$	125
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—		$	(1	)	$	—		$	1		$	—	$	(79	)


⁽¹⁾	Purchases in Level 3 primarily consist of privately-placed fixed income securities.

⁽²⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $550 million at December 31, 2017, which includes a fair value derivative adjustment of $125 million and $204 million, respectively.



	Assets																					Liabilities
Six Months Ended	Available-for-Sale Debt Securities									Equity securities			Short-term investments			Other investments			Other derivative instruments			GLB⁽¹⁾
June 30, 2017	Foreign			Corporate securities			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities			MBS
Balance – beginning of period	$	74		$	681		$	45		$	41		$	25		$	225		$	13		$	559
Transfers into Level 3	—			57			—			—			—			—			—			9
Transfers out of Level 3	—			(67		)	—			—			—			—			(9		)	—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	2			(8		)	—			1			—			3			—			—
Net Realized Gains/Losses	1			(1		)	—			—			—			—			(2		)	(211		)
Purchases	33			221			1			6			14			24			—			—
Sales	(22		)	(55		)	(1		)	(9		)	—			—			—			—
Settlements	(3		)	(81		)	—			—			(32		)	(9		)	—			—
Balance – end of period	$	85		$	747		$	45		$	39		$	7		$	243		$	2		$	357
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—		$	—		$	—		$	—		$	(2	)	$	(211	)

⁽¹⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $853 million at December 31, 2016, which includes a fair value derivative adjustment of $357 million and $559 million, respectively.

b

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

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
Three Months Ended	Available-for-Sale Debt Securities									Equity securities			Short-term investments			Other investments			Other derivative instruments		GLB ⁽²⁾
June 30, 2018	Foreign			Corporate securities ⁽¹⁾			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities ⁽¹⁾			MBS
Balance – beginning of period	$	176		$	1,073		$	83		$	64		$	12		$	270		$	2	$	167
Transfers into Level 3	—			6			—			—			—			—			—		—
Transfers out of Level 3	—			—			—			—			—			—			—		—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	(7		)	(9		)	—			—			—			—			—		—
Net Realized Gains/Losses	—			2			—			(3		)	—			1			—		(42		)
Purchases	95			217			—			3			1			16			—		—
Sales	(11		)	(45		)	—			(5		)	—			—			—		—
Settlements	(1		)	(63		)	(1		)	—			(1		)	(23		)	—		—
Balance – end of period	$	252		$	1,181		$	82		$	59		$	12		$	264		$	2	$	125
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—		$	(3	)	$	—		$	1		$	—	$	(42	)


⁽¹⁾	Purchases in Level 3 primarily consist of privately-placed fixed income securities.

⁽²⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $529 million at March 31, 2018, which includes a fair value derivative adjustment of $125 million and $167 million, respectively.



	Assets																				Liabilities
Three Months Ended	Available-for-Sale Debt Securities								Equity securities			Short-term investments			Other investments			Other derivative instruments			GLB ⁽¹⁾
June 30, 2017	Foreign			Corporate securities			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities			MBS
Balance – beginning of period	$	80		$	737		$	45	$	41		$	21		$	233		$	11		$	466
Transfers into Level 3	—			28			—		—			—			—			—			9
Transfers out of Level 3	—			(13		)	—		—			—			—			(9		)	—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	3			—			—		1			—			(1		)	—			—
Net Realized Gains/Losses	2			—			—		—			—			—			—			(118		)
Purchases	19			65			—		6			7			16			—			—
Sales	(19		)	(28		)	—		(9		)	—			—			—			—
Settlements	—			(42		)	—		—			(21		)	(5		)	—			—
Balance – end of period	$	85		$	747		$	45	$	39		$	7		$	243		$	2		$	357
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—	$	—		$	—		$	—		$	—		$	(118	)

⁽¹⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $774 million at March 31, 2017, which includes a fair value derivative adjustment of $357 million and $466 million, respectively.



	Assets																		Liabilities
Six Months Ended	Available-for-Sale Debt Securities									Equity securities			Short-term investments			Other investments			Other derivative instruments		GLB⁽²⁾
June 30, 2018	Foreign			Corporate securities ⁽¹⁾			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities ⁽¹⁾			MBS
Balance – beginning of period	$	93		$	1,037		$	78		$	44		$	—		$	263		$	2	$	204
Transfers into Level 3	7			6			1			—			5			—			—		—
Transfers out of Level 3	—			(10		)	—			—			—			—			—		—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	2			(12		)	—			1			—			2			—		—
Net Realized Gains/Losses	—			2			—			(1		)	—			1			—		(79		)
Purchases	182			356			4			20			9			30			—		—
Sales	(30		)	(96		)	—			(5		)	—			—			—		—
Settlements	(2		)	(102		)	(1		)	—			(2		)	(32		)	—		—
Balance – end of period	$	252		$	1,181		$	82		$	59		$	12		$	264		$	2	$	125
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—		$	(1	)	$	—		$	1		$	—	$	(79	)


⁽¹⁾	Purchases in Level 3 primarily consist of privately-placed fixed income securities.

⁽²⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $550 million at December 31, 2017, which includes a fair value derivative adjustment of $125 million and $204 million, respectively.



	Assets																					Liabilities
Six Months Ended	Available-for-Sale Debt Securities									Equity securities			Short-term investments			Other investments			Other derivative instruments			GLB⁽¹⁾
June 30, 2017	Foreign			Corporate securities			MBS
(in millions of U.S. dollars)	Foreign			Corporate securities			MBS
Balance – beginning of period	$	74		$	681		$	45		$	41		$	25		$	225		$	13		$	559
Transfers into Level 3	—			57			—			—			—			—			—			9
Transfers out of Level 3	—			(67		)	—			—			—			—			(9		)	—
Change in Net Unrealized Gains (Losses) included in OCI, including foreign exchange	2			(8		)	—			1			—			3			—			—
Net Realized Gains/Losses	1			(1		)	—			—			—			—			(2		)	(211		)
Purchases	33			221			1			6			14			24			—			—
Sales	(22		)	(55		)	(1		)	(9		)	—			—			—			—
Settlements	(3		)	(81		)	—			—			(32		)	(9		)	—			—
Balance – end of period	$	85		$	747		$	45		$	39		$	7		$	243		$	2		$	357
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—		$	—		$	—		$	—		$	—		$	—		$	(2	)	$	(211	)

⁽¹⁾

Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $853 million at December 31, 2016, which includes a fair value derivative adjustment of $357 million and $559 million, respectively.

b

Carrying Values And Fair Values Of Financial Instruments Not Measured At Fair Value

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



June 30, 2018	Fair Value								Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total		Carrying Value
Assets:
Fixed maturities held to maturity
U.S. Treasury and agency	$	1,079	$	54	$	—	$	1,133	$	1,143
Foreign	—		1,675		—		1,675		1,678
Corporate securities	—		2,633		32		2,665		2,736
Mortgage-backed securities	—		2,585		—		2,585		2,640
States, municipalities, and political subdivisions	—		5,607		—		5,607		5,663
Total assets	$	1,079	$	12,554	$	32	$	13,665	$	13,860
Liabilities:
Repurchase agreements	$	—	$	1,413	$	—	$	1,413	$	1,413
Short-term debt	—		615		—		615		600
Long-term debt	—		12,296		—		12,296		12,184
Trust preferred securities	—		433		—		433		308
Total liabilities	$	—	$	14,757	$	—	$	14,757	$	14,505



December 31, 2017	Fair Value								Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total		Carrying Value
Assets:
Fixed maturities held to maturity
U.S. Treasury and agency	$	857	$	58	$	—	$	915	$	908
Foreign	—		1,757		—		1,757		1,738
Corporate securities	—		3,184		35		3,219		3,159
Mortgage-backed securities	—		2,742		—		2,742		2,724
States, municipalities, and political subdivisions	—		5,841		—		5,841		5,806
Total assets	$	857	$	13,582	$	35	$	14,474	$	14,335
Liabilities:
Repurchase agreements	$	—	$	1,408	$	—	$	1,408	$	1,408
Short-term debt	—		1,013		—		1,013		1,013
Long-term debt	—		12,332		—		12,332		11,556
Trust preferred securities	—		468		—		468		308
Total liabilities	$	—	$	15,221	$	—	$	15,221	$	14,285

Unpaid losses and loss expenses Unpaid losses and loss expenses (Tables)

6 Months Ended

Jun. 30, 2018

Liability for Claims and Claims Adjustment Expense [Abstract]

Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block]

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



	Six Months Ended June 30
(in millions of U.S. dollars)	2018			2017
Gross unpaid losses and loss expenses – beginning of period	$	63,179		$	60,540
Reinsurance recoverable on unpaid losses - beginning of period ⁽¹⁾	(14,014		)	(12,708		)
Net unpaid losses and loss expenses – beginning of period	49,165			47,832
Net losses and loss expenses incurred in respect of losses occurring in:
Current year	9,026			8,396
Prior years ⁽²⁾	(437		)	(461		)
Total	8,589			7,935
Net losses and loss expenses paid in respect of losses occurring in:
Current year	2,346			2,271
Prior years	6,269			5,758
Total	8,615			8,029
Foreign currency revaluation and other	(96		)	171
Net unpaid losses and loss expenses – end of period	49,043			47,909
Reinsurance recoverable on unpaid losses ⁽³⁾	13,735			12,485
Gross unpaid losses and loss expenses – end of period	$	62,778		$	60,394


⁽¹⁾	Net of provision for uncollectible reinsurance of $321 million and $300 million at December 31, 2017 and 2016, respectively.


⁽²⁾	Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments, and earned premiums totaling $37 million and $60 million for the six months ended June 30, 2018 and 2017, respectively.


⁽³⁾	Net of provision for uncollectible reinsurance of $319 million and $335 million at June 30, 2018 and 2017, respectively.

Prior Period Development, by Segment [Table Text Block]



	Three Months Ended June 30									Six Months Ended June 30
(in millions of U.S. dollars)	Long-tail			Short-tail			Total			Long-tail			Short-tail			Total
2018
North America Commercial P&C Insurance	$	(104	)	$	(51	)	$	(155	)	$	(96	)	$	(160	)	$	(256	)
North America Personal P&C Insurance	—			7			7			—			1			1
North America Agricultural Insurance	—			—			—			—			(76		)	(76		)
Overseas General Insurance	(2		)	(70		)	(72		)	(2		)	(92		)	(94		)
Global Reinsurance	(30		)	14			(16		)	(30		)	—			(30		)
Corporate	45			—			45			55			—			55
Total	$	(91	)	$	(100	)	$	(191	)	$	(73	)	$	(327	)	$	(400	)
2017
North America Commercial P&C Insurance	$	(83	)	$	(48	)	$	(131	)	$	(177	)	$	(133	)	$	(310	)
North America Personal P&C Insurance	—			37			37			—			34			34
North America Agricultural Insurance	—			—			—			—			(79		)	(79		)
Overseas General Insurance	—			(88		)	(88		)	32			(108		)	(76		)
Global Reinsurance	(36		)	5			(31		)	(28		)	5			(23		)
Corporate	43			—			43			53			—			53
Total	$	(76	)	$	(94	)	$	(170	)	$	(120	)	$	(281	)	$	(401	)

Commitments, contingencies, and guarantees (Tables)

6 Months Ended

Jun. 30, 2018

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:



				June 30, 2018							December 31, 2017
	Consolidated Balance Sheet Location	Fair Value					Notional Value/ Payment Provision		Fair Value					Notional Value/ Payment Provision
(in millions of U.S. dollars)	Consolidated Balance Sheet Location	Derivative Asset		Derivative (Liability)			Notional Value/ Payment Provision		Derivative Asset		Derivative (Liability)			Notional Value/ Payment Provision
Investment and embedded derivative instruments:
Foreign currency forward contracts	OA / (AP)	$	33	$	(36	)	$	2,364	$	14	$	(27	)	$	2,064
Cross-currency swaps	OA / (AP)	—		—			45		—		—			45
Options/Futures contracts on notes and bonds	OA / (AP)	6		(6		)	1,409		4		(3		)	1,007
Convertible securities ⁽¹⁾	FM AFS / ES	9		—			10		5		—			6
		$	48	$	(42	)	$	3,828	$	23	$	(30	)	$	3,122
Other derivative instruments:
Futures contracts on equities⁽²⁾	OA / (AP)	$	32	$	—		$	1,632	$	—	$	(21	)	$	1,553
Other	OA / (AP)	18		(2		)	351		1		(2		)	75
		$	50	$	(2	)	$	1,983	$	1	$	(23	)	$	1,628
GLB ⁽³⁾	(AP) / (FPB)	$	—	$	(497	)	$	1,163	$	—	$	(550	)	$	1,083


⁽¹⁾	Includes fair value of embedded derivatives.


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


⁽³⁾	Includes both future policy benefits reserves and fair value derivative adjustment. 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.

Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations

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



	Three Months Ended						Six Months Ended
	June 30						June 30
(in millions of U.S. dollars)	2018			2017			2018			2017
Investment and embedded derivative instruments:
Foreign currency forward contracts	$	3		$	(7	)	$	7		$	7
All other futures contracts and options	21			(9		)	34			(17		)
Total investment and embedded derivative instruments	$	24		$	(16	)	$	41		$	(10	)
GLB and other derivative instruments:
GLB ⁽¹⁾	$	41		$	118		$	79		$	211
Futures contracts on equities ⁽²⁾	(44		)	(38		)	(22		)	(112		)
Other	8			(1		)	10			1
Total GLB and other derivative instruments	$	5		$	79		$	67		$	100
	$	29		$	63		$	108		$	90


⁽¹⁾	Excludes foreign exchange gains (losses) related to GLB.


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

Transfer of Certain Financial Assets Accounted for as Secured Borrowings

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
	June 30		December 31
	2018		2017
(in millions of U.S. dollars)	Overnight and Continuous
Collateral held under securities lending agreements:
Cash	$	990	$	828
U.S. Treasury and agency	100		36
Foreign	909		712
Corporate securities	14		—
Mortgage-backed securities	55		74
Equity securities	287		87
	$	2,355	$	1,737
Gross amount of recognized liability for securities lending payable	$	2,355	$	1,737

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
	June 30, 2018						December 31, 2017
	Up to 30 Days		Greater than 90 Days		Total		Up to 30 Days		Greater than 90 Days		Total
(in millions of U.S. dollars)	Up to 30 Days		Greater than 90 Days		Total		Up to 30 Days		Greater than 90 Days		Total
Collateral pledged under repurchase agreements:
U.S. Treasury and agency	$	245	$	9	$	254	$	9	$	230	$	239
Mortgage-backed securities	333		862		1,195		369		826		1,195
	$	578	$	871	$	1,449	$	378	$	1,056	$	1,434
Gross amount of recognized liabilities for repurchase agreements					$	1,413					$	1,408
Difference ⁽¹⁾					$	36					$	26


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

Shareholders' Equity (Tables)

6 Months Ended

Jun. 30, 2018

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):



	Three Months Ended						Six Months Ended
	June 30						June 30
	2018			2017			2018			2017
	CHF	USD		CHF	USD		CHF	USD		CHF	USD
Total dividend distributions per common share	0.73	$	0.73	0.69	$	0.71	1.39	$	1.44	1.38	$	1.40

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:



	Three Months Ended June 30				Six Months Ended June 30				July 1, 2018 through July 31, 2018
(in millions of U.S. dollars, except share data)	2018		2017		2018		2017		July 1, 2018 through July 31, 2018
Number of shares repurchased	2,443,855		2,381,566		2,443,855		3,417,630		740,869
Cost of shares repurchased	$	324	$	335	$	324	$	475	$	100
Repurchase authorization remaining at end of period	$	676	$	525	$	676	$	525	$	576

Postretirement benefits (Tables)

6 Months Ended

Jun. 30, 2018

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

9. Postretirement benefits

The components of net pension and other postretirement benefit costs (benefits) reflected in Net income in the Consolidated statements of operations were as follows:



	Pension Benefits												Other Postretirement Benefits
	2018						2017						2018			2017
Three Months Ended June 30	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
(in millions of U.S. dollars)	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Service cost	$	15		$	3		$	16		$	4		$	—		$	2
Interest cost	27			7			26			7			1			—
Expected return on plan assets	(53		)	(13		)	(48		)	(10		)	(1		)	(1		)
Amortization of net actuarial loss	—			—			—			1			—			—
Amortization of prior service cost	—			—			—			—			(22		)	(23		)
Curtailments	—			—			—			(8		)	(1		)	—
Settlements	1			—			—			—			—			—
Net periodic (benefit) cost	$	(10	)	$	(3	)	$	(6	)	$	(6	)	$	(23	)	$	(22	)



	Pension Benefits												Other Postretirement Benefits
	2018						2017						2018			2017
Six Months Ended June 30	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
(in millions of U.S. dollars)	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Service cost	$	29		$	6		$	32		$	8		$	—		$	2
Interest cost	53			14			52			14			2			1
Expected return on plan assets	(106		)	(26		)	(95		)	(20		)	(2		)	(2		)
Amortization of net actuarial loss	—			—			—			1			—			—
Amortization of prior service cost	—			—			—			—			(43		)	(46		)
Curtailments	—			—			—			(8		)	(1		)	—
Settlements	1			—			—			—			—			—
Net periodic (benefit) cost	$	(23	)	$	(6	)	$	(11	)	$	(5	)	$	(44	)	$	(45	)

Segment information (Tables)

6 Months Ended

Jun. 30, 2018

Segment Reporting [Abstract]

Operations By Segment

The following tables present the Statement of Operations by segment:



	North America Commercial P&C Insurance			North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance			Global Reinsurance			Life Insurance		Corporate			Chubb Consolidated
For the Three Months Ended
June 30, 2018
(in millions of U.S. dollars)
Net premiums written	$	3,331		$	1,335	$	388	$	2,199		$	197		$	565	$	—		$	8,015
Net premiums earned	3,277			1,156		351		2,161			167			552		—			7,664
Losses and loss expenses	2,084			728		289		1,071			83			184		48			4,487
Policy benefits	—			—		—		—			—			150		—			150
Policy acquisition costs	448			228		26		584			40			138		—			1,464
Administrative expenses	253			68		1		266			9			80		70			747
Underwriting income (loss)	492			132		35		240			35			—		(118		)	816
Net investment income (loss)	510			59		6		155			65			85		(52		)	828
Other (income) expense	(13		)	1		1		(12		)	(6		)	8		(94		)	(115		)
Amortization expense of purchased intangibles	—			3		7		11			—			—		64			85
Segment income (loss)	$	1,015		$	187	$	33	$	396		$	106		$	77	$	(140	)	$	1,674
Net realized gains (losses) including OTTI																18			18
Interest expense																167			167
Chubb integration expenses																13			13
Income tax expense																218			218
Net income (loss)																$	(520	)	$	1,294



	North America Commercial P&C Insurance ⁽¹⁾			North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance ⁽¹⁾			Global Reinsurance		Life Insurance			Corporate			Chubb Consolidated
For the Three Months Ended
June 30, 2017
(in millions of U.S. dollars)
Net premiums written	$	3,203		$	1,255	$	403	$	2,007		$	190	$	523		$	—		$	7,581
Net premiums earned	3,099			1,093		344		2,018			168		515			—			7,237
Losses and loss expenses	1,936			683		290		964			46		182			45			4,146
Policy benefits	—			—		—		—			—		163			—			163
Policy acquisition costs	464			230		27		555			43		130			—			1,449
Administrative expenses	241			66		2		243			12		77			65			706
Underwriting income (loss)	458			114		25		256			67		(37		)	(110		)	773
Net investment income (loss)	490			56		6		148			65		77			(72		)	770
Other (income) expense	(4		)	1		1		(3		)	1		(12		)	(129		)	(145		)
Amortization expense of purchased intangibles	—			5		7		11			—		—			42			65
Segment income (loss)	$	952		$	164	$	23	$	396		$	131	$	52		$	(95	)	$	1,623
Net realized gains (losses) including OTTI																101			101
Interest expense																147			147
Chubb integration expenses																72			72
Income tax expense																200			200
Net income (loss)																$	(413	)	$	1,305


⁽¹⁾	The 2017 net premiums written amount was revised to reflect the transfer of certain multinational accounts ($1 million) from the North America Commercial P&C Insurance segment to the Overseas General Insurance segment to better align the reporting with the management of these businesses in 2018. There is no impact on a consolidated basis.



	North America Commercial P&C Insurance			North America Personal P&C Insurance		North America Agricultural Insurance			Overseas General Insurance			Global Reinsurance			Life Insurance			Corporate			Chubb Consolidated
For the Six Months Ended
June 30, 2018
(in millions of U.S. dollars)
Net premiums written	$	6,143		$	2,383	$	496		$	4,583		$	390		$	1,124		$	—		$	15,119
Net premiums earned	6,306			2,296		394			4,268			335			1,092			—			14,691
Losses and loss expenses	3,992			1,614		236			2,149			150			389			59			8,589
Policy benefits	—			—		—			—			—			301			—			301
Policy acquisition costs	920			465		25			1,172			80			266			—			2,928
Administrative expenses	484			133		(2		)	505			19			158			142			1,439
Underwriting income (loss)	910			84		135			442			86			(22		)	(201		)	1,434
Net investment income (loss)	1,013			118		13			306			129			168			(113		)	1,634
Other (income) expense	(19		)	1		1			(5		)	(13		)	4			(131		)	(162		)
Amortization expense of purchased intangibles	—			6		14			21			—			1			128			170
Segment income (loss)	$	1,942		$	195	$	133		$	732		$	228		$	141		$	(311	)	$	3,060
Net realized gains (losses) including OTTI																		16			16
Interest expense																		324			324
Chubb integration expenses																		23			23
Income tax expense																		353			353
Net income (loss)																		$	(995	)	$	2,376



	North America Commercial P&C Insurance ⁽¹⁾		North America Personal P&C Insurance		North America Agricultural Insurance			Overseas General Insurance ⁽¹⁾			Global Reinsurance		Life Insurance			Corporate			Chubb Consolidated
For the Six Months Ended
June 30, 2017
(in millions of U.S. dollars)
Net premiums written	$	5,933	$	2,239	$	464		$	4,219		$	389	$	1,047		$	—		$	14,291
Net premiums earned	6,140		2,179		358			3,954			357		1,021			—			14,009
Losses and loss expenses	3,796		1,316		217			2,035			140		375			56			7,935
Policy benefits	—		—		—			—			—		331			—			331
Policy acquisition costs	951		447		26			1,084			94		244			—			2,846
Administrative expenses	472		131		(3		)	488			22		149			123			1,382
Underwriting income (loss)	921		285		118			347			101		(78		)	(179		)	1,515
Net investment income (loss)	968		111		12			296			127		152			(151		)	1,515
Other (income) expense	—		2		1			(4		)	1		(41		)	(174		)	(215		)
Amortization expense of purchased intangibles	—		8		14			22			—		1			84			129
Segment income (loss)	$	1,889	$	386	$	115		$	625		$	227	$	114		$	(240	)	$	3,116
Net realized gains (losses) including OTTI																94			94
Interest expense																301			301
Chubb integration expenses																183			183
Income tax expense																328			328
Net income (loss)																$	(958	)	$	2,398


⁽¹⁾	The 2017 net premiums written amount was revised to reflect the transfer of certain multinational accounts ($13 million) from the North America Commercial P&C Insurance segment to the Overseas General Insurance segment to better align the reporting with the management of these businesses in 2018. There is no impact on a consolidated basis.

Earnings per share (Tables)

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Schedule Of Earnings Per Share, Basic And Diluted



	Three Months Ended				Six Months Ended
	June 30				June 30
(in millions of U.S. dollars, except share and per share data)	2018		2017		2018		2017
Numerator:
Net income	$	1,294	$	1,305	$	2,376	$	2,398
Denominator:
Denominator for basic earnings per share:
Weighted-average shares outstanding	465,276,597		467,981,077		465,488,724		468,244,458
Denominator for diluted earnings per share:
Share-based compensation plans	3,103,727		3,872,860		3,489,013		3,900,678
Weighted-average shares outstanding and assumed conversions	468,380,324		471,853,937		468,977,737		472,145,136
Basic earnings per share	$	2.78	$	2.79	$	5.10	$	5.12
Diluted earnings per share	$	2.76	$	2.77	$	5.07	$	5.08
Potential anti-dilutive share conversions	3,814,491		2,066,578		3,305,735		1,467,556

Information provided in connection with outstanding debt of subsidiaries (Tables)

6 Months Ended

Jun. 30, 2018

Table Text Block Supplement [Abstract]

Condensed Consolidating Balance Sheet

Condensed Consolidating Balance Sheet at June 30, 2018



(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	$	—	$	172	$	101,014	$	—		$	101,186
Cash ⁽¹⁾	1		1		2,238		(1,240		)	1,000
Restricted cash	—		—		101		—			101
Insurance and reinsurance balances receivable	—		—		11,297		(956		)	10,341
Reinsurance recoverable on losses and loss expenses	—		—		27,117		(12,325		)	14,792
Reinsurance recoverable on policy benefits	—		—		1,127		(923		)	204
Value of business acquired	—		—		311		—			311
Goodwill and other intangible assets	—		—		21,759		—			21,759
Investments in subsidiaries	42,919		51,706		—		(94,625		)	—
Due from subsidiaries and affiliates, net	8,686		—		257		(8,943		)	—
Other assets	2		655		18,760		(1,577		)	17,840
Total assets	$	51,608	$	52,534	$	183,981	$	(120,589	)	$	167,534
Liabilities
Unpaid losses and loss expenses	$	—	$	—	$	73,427	$	(10,649	)	$	62,778
Unearned premiums	—		—		16,815		(1,067		)	15,748
Future policy benefits	—		—		6,393		(923		)	5,470
Due to subsidiaries and affiliates, net	—		8,943		—		(8,943		)	—
Affiliated notional cash pooling programs ⁽¹⁾	403		837		—		(1,240		)	—
Repurchase agreements	—		—		1,413		—			1,413
Short-term debt	—		600		—		—			600
Long-term debt	—		12,173		11		—			12,184
Trust preferred securities	—		308		—		—			308
Other liabilities	234		2,248		18,722		(3,142		)	18,062
Total liabilities	637		25,109		116,781		(25,964		)	116,563
Total shareholders’ equity	50,971		27,425		67,200		(94,625		)	50,971
Total liabilities and shareholders’ equity	$	51,608	$	52,534	$	183,981	$	(120,589	)	$	167,534

⁽¹⁾

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Balance Sheet at December 31, 2017



(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	$	—	$	168	$	102,276	$	—		$	102,444
Cash ⁽¹⁾	3		1		839		(115		)	728
Restricted cash	—		—		123		—			123
Insurance and reinsurance balances receivable	—		—		10,820		(1,486		)	9,334
Reinsurance recoverable on losses and loss expenses	—		—		27,514		(12,480		)	15,034
Reinsurance recoverable on policy benefits	—		—		1,194		(1,010		)	184
Value of business acquired	—		—		326		—			326
Goodwill and other intangible assets	—		—		22,054		—			22,054
Investments in subsidiaries	41,909		51,165		—		(93,074		)	—
Due from subsidiaries and affiliates, net	9,639		—		—		(9,639		)	—
Other assets	3		287		20,578		(4,073		)	16,795
Total assets	$	51,554	$	51,621	$	185,724	$	(121,877	)	$	167,022
Liabilities
Unpaid losses and loss expenses	$	—	$	—	$	74,767	$	(11,588	)	$	63,179
Unearned premiums	—		—		18,875		(3,659		)	15,216
Future policy benefits	—		—		6,331		(1,010		)	5,321
Due to subsidiaries and affiliates, net	—		9,432		207		(9,639		)	—
Affiliated notional cash pooling programs ⁽¹⁾	—		115		—		(115		)	—
Repurchase agreements	—		—		1,408		—			1,408
Short-term debt	—		1,013		—		—			1,013
Long-term debt	—		11,546		10		—			11,556
Trust preferred securities	—		308		—		—			308
Other liabilities	382		1,411		18,848		(2,792		)	17,849
Total liabilities	382		23,825		120,446		(28,803		)	115,850
Total shareholders’ equity	51,172		27,796		65,278		(93,074		)	51,172
Total liabilities and shareholders’ equity	$	51,554	$	51,621	$	185,724	$	(121,877	)	$	167,022

⁽¹⁾

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Condensed Consolidating Statement Of Operations and Comprehensive Income

Condensed Consolidating Statements of Operations and Comprehensive Income



For the Three Months Ended June 30, 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)	Chubb Limited (Parent Guarantor)			Chubb INA Holdings Inc. (Subsidiary Issuer)			Other Chubb Limited Subsidiaries			Consolidating Adjustments and Eliminations			Chubb Limited Consolidated
Net premiums written	$	—		$	—		$	8,015		$	—		$	8,015
Net premiums earned	—			—			7,664			—			7,664
Net investment income	1			5			822			—			828
Equity in earnings of subsidiaries	1,241			454			—			(1,695		)	—
Net realized gains (losses) including OTTI	2			73			(57		)	—			18
Losses and loss expenses	—			—			4,487			—			4,487
Policy benefits	—			—			150			—			150
Policy acquisition costs and administrative expenses	23			19			2,169			—			2,211
Interest (income) expense	(76		)	204			39			—			167
Other (income) expense	(4		)	8			(119		)	—			(115		)
Amortization of purchased intangibles	—			—			85			—			85
Chubb integration expenses	2			—			11			—			13
Income tax expense (benefit)	5			(36		)	249			—			218
Net income	$	1,294		$	337		$	1,358		$	(1,695	)	$	1,294
Comprehensive income (loss)	$	277		$	(462	)	$	352		$	110		$	277

Condensed Consolidating Statements of Operations and Comprehensive Income



For the Three Months Ended June 30, 2017	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)	Chubb Limited (Parent Guarantor)			Chubb INA Holdings Inc. (Subsidiary Issuer)			Other Chubb Limited Subsidiaries			Consolidating Adjustments and Eliminations			Chubb Limited Consolidated
Net premiums written	$	—		$	—		$	7,581		$	—		$	7,581
Net premiums earned	—			—			7,237			—			7,237
Net investment income	2			4			764			—			770
Equity in earnings of subsidiaries	1,253			665			—			(1,918		)	—
Net realized gains (losses) including OTTI	(2		)	(1		)	104			—			101
Losses and loss expenses	—			—			4,146			—			4,146
Policy benefits	—			—			163			—			163
Policy acquisition costs and administrative expenses	18			(2		)	2,139			—			2,155
Interest (income) expense	(84		)	212			19			—			147
Other (income) expense	4			10			(159		)	—			(145		)
Amortization of purchased intangibles	—			—			65			—			65
Chubb integration expenses	6			4			62			—			72
Income tax expense (benefit)	4			(87		)	283			—			200
Net income	$	1,305		$	531		$	1,387		$	(1,918	)	$	1,305
Comprehensive income	$	1,675		$	920		$	1,756		$	(2,676	)	$	1,675

Condensed Consolidating Statements of Operations and Comprehensive Income



For the Six Months Ended June 30, 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)	Chubb Limited (Parent Guarantor)			Chubb INA Holdings Inc. (Subsidiary Issuer)			Other Chubb Limited Subsidiaries			Consolidating Adjustments and Eliminations			Chubb Limited Consolidated
Net premiums written	$	—		$	—		$	15,119		$	—		$	15,119
Net premiums earned	—			—			14,691			—			14,691
Net investment income	3			9			1,622			—			1,634
Equity in earnings of subsidiaries	2,263			1,339			—			(3,602		)	—
Net realized gains (losses) including OTTI	—			49			(33		)	—			16
Losses and loss expenses	—			—			8,589			—			8,589
Policy benefits	—			—			301			—			301
Policy acquisition costs and administrative expenses	41			41			4,285			—			4,367
Interest (income) expense	(156		)	413			67			—			324
Other (income) expense	(9		)	16			(169		)	—			(162		)
Amortization of purchased intangibles	—			—			170			—			170
Chubb integration expenses	4			1			18			—			23
Income tax expense (benefit)	10			(95		)	438			—			353
Net income	$	2,376		$	1,021		$	2,581		$	(3,602	)	$	2,376
Comprehensive income (loss)	$	730		$	(246	)	$	966		$	(720	)	$	730

Condensed Consolidating Statements of Operations and Comprehensive Income



For the Six Months Ended June 30, 2017	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)	Chubb Limited (Parent Guarantor)			Chubb INA Holdings Inc. (Subsidiary Issuer)			Other Chubb Limited Subsidiaries			Consolidating Adjustments and Eliminations			Chubb Limited Consolidated
Net premiums written	$	—		$	—		$	14,291		$	—		$	14,291
Net premiums earned	—			—			14,009			—			14,009
Net investment income	2			7			1,506			—			1,515
Equity in earnings of subsidiaries	2,280			1,366			—			(3,646		)	—
Net realized gains (losses) including OTTI	(2		)	(14		)	110			—			94
Losses and loss expenses	—			—			7,935			—			7,935
Policy benefits	—			—			331			—			331
Policy acquisition costs and administrative expenses	36			12			4,180			—			4,228
Interest (income) expense	(168		)	433			36			—			301
Other (income) expense	(2		)	25			(238		)	—			(215		)
Amortization of purchased intangibles	—			—			129			—			129
Chubb integration expenses	6			53			124			—			183
Income tax expense (benefit)	10			(199		)	517			—			328
Net income	$	2,398		$	1,035		$	2,611		$	(3,646	)	$	2,398
Comprehensive income	$	3,082		$	1,711		$	3,294		$	(5,005	)	$	3,082

Condensed Consolidating Statement of Cash Flows



For the Six Months Ended June 30, 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	$	43		$	3,042		$	2,187		$	(3,075	)	$	2,197
Cash flows from investing activities
Purchases of fixed maturities available for sale	—			(22		)	(12,275		)	—			(12,297		)
Purchases of fixed maturities held to maturity	—			—			(337		)	—			(337		)
Purchases of equity securities	—			—			(85		)	—			(85		)
Sales of fixed maturities available for sale	—			—			6,858			—			6,858
Sales of equity securities	—			—			83			—			83
Maturities and redemptions of fixed maturities available for sale	—			14			3,906			—			3,920
Maturities and redemptions of fixed maturities held to maturity	—			—			732			—			732
Net change in short-term investments	—			6			395			—			401
Net derivative instruments settlements	—			(8		)	13			—			5
Private equity contributions	—			—			(813		)	—			(813		)
Private equity distributions	—			—			413			—			413
Capital contribution	(750		)	(3,500		)	—			4,250			—
Other	—			(7		)	(133		)	—			(140		)
Net cash flows used for investing activities	(750		)	(3,517		)	(1,243		)	4,250			(1,260		)
Cash flows from financing activities
Dividends paid on Common Shares	(661		)	—			—			—			(661		)
Common Shares repurchased	—			—			(347		)	—			(347		)
Proceeds from issuance of long-term debt	—			2,171			—			—			2,171
Repayment of long-term debt	—			(1,900		)	—			—			(1,900		)
Proceeds from issuance of repurchase agreements	—			—			1,014			—			1,014
Repayment of repurchase agreements	—			—			(1,009		)	—			(1,009		)
Proceeds from share-based compensation plans	—			—			60			—			60
Dividend to parent company	—			—			(3,075		)	3,075			—
Advances (to) from affiliates	963			(518		)	(445		)	—			—
Capital contribution	—			—			4,250			(4,250		)	—
Net proceeds from (payments to) affiliated notional cash pooling programs⁽¹⁾	403			722			—			(1,125		)	—
Policyholder contract deposits	—			—			192			—			192
Policyholder contract withdrawals	—			—			(169		)	—			(169		)
Net cash flows from (used for) financing activities	705			475			471			(2,300		)	(649		)
Effect of foreign currency rate changes on cash and restricted cash	—			—			(38		)	—			(38		)
Net increase (decrease) in cash and restricted cash	(2		)	—			1,377			(1,125		)	250
Cash and restricted cash – beginning of period⁽¹⁾	3			1			962			(115		)	851
Cash and restricted cash – end of period⁽¹⁾	$	1		$	1		$	2,339		$	(1,240	)	$	1,101

⁽¹⁾

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2018 and December 31, 2017, 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 Six Months Ended June 30, 2017	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 (used for) operating activities	$	551		$	1,444		$	1,686		$	(2,041	)	$	1,640
Cash flows from investing activities
Purchases of fixed maturities available for sale	—			(5		)	(12,255		)	—			(12,260		)
Purchases of fixed maturities held to maturity	—			—			(212		)	—			(212		)
Purchases of equity securities	—			—			(82		)	—			(82		)
Sales of fixed maturities available for sale	—			—			6,873			—			6,873
Sales of equity securities	—			—			104			—			104
Maturities and redemptions of fixed maturities available for sale	—			13			5,156			—			5,169
Maturities and redemptions of fixed maturities held to maturity	—			—			408			—			408
Net change in short-term investments	—			166			188			—			354
Net derivative instruments settlements	—			(7		)	(122		)	—			(129		)
Private equity contributions	—			—			(345		)	—			(345		)
Private equity distributions	—			—			487			—			487
Other	—			2			(246		)	—			(244		)
Net cash flows from (used for) investing activities	—			169			(46		)	—			123
Cash flows from financing activities
Dividends paid on Common Shares	(646		)	—			—			—			(646		)
Common Shares repurchased	—			—			(475		)	—			(475		)
Repayment of long-term debt	—			(500		)	—			—			(500		)
Proceeds from issuance of repurchase agreements	—			—			1,343			—			1,343
Repayment of repurchase agreements	—			—			(1,338		)	—			(1,338		)
Proceeds from share-based compensation plans	—			—			89			—			89
Dividend to parent company	—			—			(2,041		)	2,041			—
Advances (to) from affiliates	264			(328		)	64			—			—
Net proceeds from affiliated notional cash pooling programs⁽¹⁾	(170		)	(619		)	—			789			—
Policyholder contract deposits	—			—			209			—			209
Policyholder contract withdrawals	—			—			(125		)	—			(125		)
Net cash flows used for financing activities	(552		)	(1,447		)	(2,274		)	2,830			(1,443		)
Effect of foreign currency rate changes on cash and restricted cash	—			—			11			—			11
Net increase (decrease) in cash and restricted cash	(1		)	166			(623		)	789			331
Cash and restricted cash – beginning of period⁽¹⁾	1			1			2,068			(982		)	1,088
Cash and restricted cash – end of period⁽¹⁾	$	—		$	167		$	1,445		$	(193	)	$	1,419

⁽¹⁾

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2017 and December 31, 2016, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

General Schedule of Cash and Cash Equivalent (Details) - USD ($)
$ in Millions

Jun. 30, 2018

Dec. 31, 2017

Jun. 30, 2017

Dec. 31, 2016

Cash and Cash Equivalents [Line Items]

$ 1,000

^[1]

$ 728

^[2]

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents

^[1]

101

123

$ 1,101

$ 851

$ 1,419

$ 1,088

[1]

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 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. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

General Goodwill (Details) $ in Millions	6 Months Ended
General Goodwill (Details) $ in Millions	Jun. 30, 2018 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Period Increase (Decrease)	$ (65)

General Adoption of New Accounting Pronouncements (Details) $ in Millions		12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		$ 450
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Tax	$ 7
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	(417)	$ (417)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] \| Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent	$ (454)

Investments (Narrative) (Detail) $ in Millions	3 Months Ended		6 Months Ended
Investments (Narrative) (Detail) $ in Millions	Jun. 30, 2018 USD ($) Security	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) Security	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Investment [Line Items]
Net unrealized appreciation (depreciation) included in OCI	$ 0	$ 3	$ 4	$ 3
Unrealized appreciation(depreciation) portion of AOCI with OTTI included in AOCI	$ 3		$ 3		$ 7
Percentage of mortgage-backed securities represented by investments in US government agency bonds	81.00%		81.00%		83.00%
Moodys Historical Mean Recovery Rate			42.00%
Company Assumed Recovery Rate			32.00%
Operating Lease, Impairment Loss	$ 22		$ 22
Available-for-sale Equity Securities, Amortized Cost Basis	933		933		$ 737
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax					212
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax					12
Equity securities, at fair value (cost – $933 and $737)	$ 933		$ 933		937
Total number of fixed maturities \| Security	31,062		31,062
Number of fixed maturities in an unrealized loss position \| Security	17,926		17,926
Largest single unrealized loss in the fixed maturities	$ 11		$ 11
Restricted assets in fixed maturities and short-term investments	21,200		21,200		23,300
Restricted assets in cash	101		101		$ 123
Corporate [Member]
Investment [Line Items]
Credit losses recognized in net income	1	1	1	2
Collateralized Mortgage Backed Securities [Member]
Investment [Line Items]
Credit losses recognized in net income	0	$ 0	0	$ 0
Junior Subordinated Debt [Member] \| Chubb INA Senior Notes Due 2037 [Member]
Investment [Line Items]
Gain (Loss) on Extinguishment of Debt	$ (36)		$ (36)

Investments Investments (Schedule Of Amortized Cost and Fair Value of Available-for-sale Securities and Related OTTI Recognized in AOCI) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	$ 78,546	$ 77,835
Available-for-sale,Gross Unrealized Gain	769	1,528
Available-for-sale, Gross Unrealized Depreciation	(1,352)	(424)
Available for sale, Fair Value	77,963	78,939
Available for sale, OTTI recognized in AOCI	(5)	(6)
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	3,827	3,701
Available-for-sale,Gross Unrealized Gain	18	32
Available-for-sale, Gross Unrealized Depreciation	(81)	(35)
Available for sale, Fair Value	3,764	3,698
Available for sale, OTTI recognized in AOCI	0	0
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	21,884	20,514
Available-for-sale,Gross Unrealized Gain	421	622
Available-for-sale, Gross Unrealized Depreciation	(294)	(106)
Available for sale, Fair Value	22,011	21,030
Available for sale, OTTI recognized in AOCI	0	(1)
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	24,665	23,453
Available-for-sale,Gross Unrealized Gain	235	638
Available-for-sale, Gross Unrealized Depreciation	(415)	(95)
Available for sale, Fair Value	24,485	23,996
Available for sale, OTTI recognized in AOCI	(4)	(4)
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	15,853	15,279
Available-for-sale,Gross Unrealized Gain	40	111
Available-for-sale, Gross Unrealized Depreciation	(410)	(100)
Available for sale, Fair Value	15,483	15,290
Available for sale, OTTI recognized in AOCI	(1)	(1)
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, at amortized cost	12,317	14,888
Available-for-sale,Gross Unrealized Gain	55	125
Available-for-sale, Gross Unrealized Depreciation	(152)	(88)
Available for sale, Fair Value	12,220	14,925
Available for sale, OTTI recognized in AOCI	$ 0	$ 0

Investments (Schedule Of Amortized Cost And Fair Value Of HTM Fixed Maturities And Related OTTI Recognized In Accumulated Other Comprehensive Income) (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Investment [Line Items]
Held to maturity, Amortized Cost	$ 13,860	$ 14,335
Held to maturity, Gross Unrealized Appreciation	60	179
Held to maturity, Gross Unrealized Depreciation	(255)	(40)
Held to maturity, at Fair Value	13,665	14,474
Held to maturity, OTTI recognized in AOCI		0
U.S. Treasury And Agency [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	1,143	908
Held to maturity, Gross Unrealized Appreciation	9	12
Held to maturity, Gross Unrealized Depreciation	(19)	(5)
Held to maturity, at Fair Value	1,133	915
Held to maturity, OTTI recognized in AOCI	0	0
Foreign [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	1,678	1,738
Held to maturity, Gross Unrealized Appreciation	14	27
Held to maturity, Gross Unrealized Depreciation	(17)	(8)
Held to maturity, at Fair Value	1,675	1,757
Held to maturity, OTTI recognized in AOCI	0	0
Corporate [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	2,736	3,159
Held to maturity, Gross Unrealized Appreciation	14	67
Held to maturity, Gross Unrealized Depreciation	(85)	(7)
Held to maturity, at Fair Value	2,665	3,219
Held to maturity, OTTI recognized in AOCI	0	0
Collateralized Mortgage Backed Securities [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	2,640	2,724
Held to maturity, Gross Unrealized Appreciation	7	23
Held to maturity, Gross Unrealized Depreciation	(62)	(5)
Held to maturity, at Fair Value	2,585	2,742
Held to maturity, OTTI recognized in AOCI	0	0
States, Municipalities, And Political Subdivisions [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	5,663	5,806
Held to maturity, Gross Unrealized Appreciation	16	50
Held to maturity, Gross Unrealized Depreciation	(72)	(15)
Held to maturity, at Fair Value	5,607	5,841
Held to maturity, OTTI recognized in AOCI	$ 0	$ 0

Investments (Schedule Of Fixed Maturities By Contractual Maturity) (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Available for sale, Due in 1 year or less, Amortized Cost	$ 3,801	$ 3,164
Available for sale, Due after 1 year through 5 years, Amortized Cost	26,591	24,749
Available for sale, Due after 5 years though 10 years, Amortized Cost	24,016	25,388
Available for sale, Due after 10 years, Amortized Cost	8,285	9,255
Available for sale, Subtotal, Amortized Cost	62,693	62,556
Available for sale, Mortgage-backed securities, Amortized Cost	15,853	15,279
Available for sale, at amortized cost	78,546	77,835
Available for sale, Due in 1 year or less, Fair Value	3,808	3,182
Available for sale, Due after 1 year through 5 years, Fair Value	26,583	25,068
Available for sale, Due after 5 years through 10 years, Fair Value	23,695	25,704
Available for sale, Due after 10 years, Fair Value	8,394	9,695
Available for sale, Subtotal, Fair Value	62,480	63,649
Available for sale, Mortgage backed securities, Fair Value	15,483	15,290
Available for sale, Fair Value	77,963	78,939
Held to maturity, Due in 1 year or less, Amortized Cost	644	743
Held to maturity, Due after 1 year through 5 years, Amortized Cost	2,783	2,669
Held to maturity, Due after 5 years through 10 years, Amortized Cost	4,634	4,744
Held to maturity, Due after 10 years, Amortized Cost	3,159	3,455
Held to maturity, Subtotal, Amortized Cost	11,220	11,611
Held to maturity, Mortgage backed securities, Amortized Cost	2,640	2,724
Held to maturity, Amortized Cost	13,860	14,335
Held to maturity, Due in 1 year or less, Fair Value	645	746
Held to maturity, Due after 1 year through 5, Fair Value	2,767	2,688
Held to maturity, Due after 5 years through 10 years, Fair Value	4,554	4,756
Held to maturity, Due after 10 years, Fair Value	3,114	3,542
Held to maturity, Subtotal, Fair Value	11,080	11,732
Held to maturity, Mortgage backed securities, Fair Value	2,585	2,742
Held to maturity, Fair Value	$ 13,665	$ 14,474

Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment (OTTI) losses gross	$ (4)	$ (9)	$ (5)	$ (28)
OTTI on fixed maturities recognized in OCI (pre-tax)	0	1	0	1
Net gains (losses) recognized during the period	(13)		5
Foreign exchange gains (losses)	140	14	63	(5)
Derivative instrument	29	63	108	90
Fair Value Adjustments On Insurance Derivative Gains Losses	41	118	79	211
Net realized gains (losses)	18	101	16	94
Investment and embedded derivative instruments
Gain (Loss) on Investments [Line Items]
Derivative instrument	24	(16)	41	(10)
S&P put options and futures
Gain (Loss) on Investments [Line Items]
Derivative instrument	(44)	(38)	(22)	(112)
Other derivative instruments
Gain (Loss) on Investments [Line Items]
Derivative instrument	8	(1)	10	1
Fixed Maturities [Member]
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment (OTTI) losses gross	(4)	(5)	(5)	(11)
OTTI on fixed maturities recognized in OCI (pre-tax)	0	1	0	1
OTTI on fixed maturities, net	(4)	(4)	(5)	(10)
Fixed maturities, Gross realized gains excluding OTTI	99	45	165	79
Fixed maturities, Gross realized losses excluding OTTI	(176)	(18)	(264)	(58)
Total fixed maturities	(81)	23	(104)	11
Equity Securities [Member]
Gain (Loss) on Investments [Line Items]
OTTI on equity securities	0	(3)	0	(8)
Net gains (losses) recognized during the period	(2)		(13)
Equity Securities, Gross realized gains excluding OTTI	6	6	16	15
Equity Securities, Gross realized losses excluding OTTI	(8)	(1)	(29)	(1)
Total equity securities	(2)	2	(13)	6
Other Investments [Member]
Gain (Loss) on Investments [Line Items]
OTTI on equity securities	0	(1)	0	(9)
Net gains (losses) recognized during the period	(11)	0	18	0
Other	$ (57)	$ 0	$ (56)	$ 1

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	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
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 [Roll Forward]
Balance of credit losses related to securities still held – beginning of period	$ 15	$ 32	$ 22	$ 35
Additions where no OTTI was previously recorded	1	1	1	1
Additions where an OTTI was previously recorded	0	0	0	1
Reductions for securities sold during the period	0	(4)	(7)	(8)
Balance of credit losses related to securities still held – end of period	$ 16	$ 29	$ 16	$ 29

Investments Schedule of Gains and Losses on Equity and Other Investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Gain (Loss) on Investments [Line Items]
Net gains (losses) recognized during the period	$ (13)		$ 5
Less: Net gains (losses) recognized from sales of securities	5		15
Unrealized gains (losses) recognized for securities still held at reporting date	(18)		(10)
Equity Securities [Member]
Gain (Loss) on Investments [Line Items]
Net gains (losses) recognized during the period	(2)		(13)
Less: Net gains (losses) recognized from sales of securities	5		15
Unrealized gains (losses) recognized for securities still held at reporting date	(7)		(28)
Other Investments [Member]
Gain (Loss) on Investments [Line Items]
Net gains (losses) recognized during the period	(11)	$ 0	18	$ 0
Less: Net gains (losses) recognized from sales of securities	0		0
Unrealized gains (losses) recognized for securities still held at reporting date	$ (11)		$ 18

Investments (Aggregate Fair Value And Gross Unrealized Loss By Length Of Time Security Has Continuously Been In Unrealized Loss Position) (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Investment [Line Items]
Fair Value, 0-12 Months		$ 28,685
Gross Unrealized Loss, 0-12 Months		(257)
Fair Value, Over 12 Months		8,885
Gross Unrealized Loss, Over 12 Months		(227)
Total Fair Value		37,570
Total Gross Unrealized Loss		(484)
U.S. Treasury And Agency [Member]
Investment [Line Items]
Fair Value, 0-12 Months	$ 2,952	2,172
Gross Unrealized Loss, 0-12 Months	(59)	(14)
Fair Value, Over 12 Months	1,275	1,249
Gross Unrealized Loss, Over 12 Months	(41)	(26)
Total Fair Value	4,227	3,421
Total Gross Unrealized Loss	(100)	(40)
Foreign [Member]
Investment [Line Items]
Fair Value, 0-12 Months	8,886	5,657
Gross Unrealized Loss, 0-12 Months	(219)	(65)
Fair Value, Over 12 Months	3,127	1,693
Gross Unrealized Loss, Over 12 Months	(92)	(49)
Total Fair Value	12,013	7,350
Total Gross Unrealized Loss	(311)	(114)
Corporate [Member]
Investment [Line Items]
Fair Value, 0-12 Months	15,899	5,210
Gross Unrealized Loss, 0-12 Months	(411)	(56)
Fair Value, Over 12 Months	1,553	1,332
Gross Unrealized Loss, Over 12 Months	(89)	(46)
Total Fair Value	17,452	6,542
Total Gross Unrealized Loss	(500)	(102)
Collateralized Mortgage Backed Securities [Member]
Investment [Line Items]
Fair Value, 0-12 Months	12,438	6,194
Gross Unrealized Loss, 0-12 Months	(325)	(31)
Fair Value, Over 12 Months	2,892	3,209
Gross Unrealized Loss, Over 12 Months	(147)	(74)
Total Fair Value	15,330	9,403
Total Gross Unrealized Loss	(472)	(105)
States, Municipalities, And Political Subdivisions [Member]
Investment [Line Items]
Fair Value, 0-12 Months	13,551	9,259
Gross Unrealized Loss, 0-12 Months	(177)	(71)
Fair Value, Over 12 Months	1,230	1,402
Gross Unrealized Loss, Over 12 Months	(47)	(32)
Total Fair Value	14,781	10,661
Total Gross Unrealized Loss	(224)	(103)
Fixed Maturities [Member]
Investment [Line Items]
Fair Value, 0-12 Months	53,726	28,492
Gross Unrealized Loss, 0-12 Months	(1,191)	(237)
Fair Value, Over 12 Months	10,077	8,885
Gross Unrealized Loss, Over 12 Months	(416)	(227)
Total Fair Value	63,803	37,377
Total Gross Unrealized Loss	$ (1,607)	(464)
Equity Securities [Member]
Investment [Line Items]
Fair Value, 0-12 Months		115
Gross Unrealized Loss, 0-12 Months		(12)
Fair Value, Over 12 Months		0
Gross Unrealized Loss, Over 12 Months		0
Total Fair Value		115
Total Gross Unrealized Loss		(12)
Other Long-term Investments [Member]
Investment [Line Items]
Fair Value, 0-12 Months		78
Gross Unrealized Loss, 0-12 Months		(8)
Fair Value, Over 12 Months		0
Gross Unrealized Loss, Over 12 Months		0
Total Fair Value		78
Total Gross Unrealized Loss		$ (8)

Investments (Schedule Of Components Of Restricted Assets) (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Trust funds	$ 14,775	$ 17,011
Deposits with U.S. regulatory authorities	2,460	2,345
Deposits with non-U.S. regulatory authorities	2,206	2,250
Assets pledged under repurchase agreements	1,449	1,434
Other pledged assets	407	414
Total restricted assets	$ 21,297	$ 23,454

Fair value measurements Fair Value Measurements (narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Level 1 to Level 2 transfers, Amount	$ 0	$ 0	$ 0	$ 0
Fair Value, Level 2 to Level 1 Transfers, Amount	$ 0	$ 0		$ 0
Realized Gain Losses As A Result of Annuitization Changes			$ 94
Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Notice Period For Redemption For Alternative Investments Investment Funds			5 days
Maximum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Notice Period For Redemption For Alternative Investments Investment Funds			120 days

Fair Value Measurements (Financial Instruments Measured At Fair Value On Recurring Basis) (Detail) - USD ($)
$ in Millions

Jun. 30, 2018

Mar. 31, 2018

^[3]

Dec. 31, 2017

Jun. 30, 2017

^[4]

Mar. 31, 2017

^[4]

Dec. 31, 2016

^[4]

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

$ 77,963

$ 78,939

933

937

5,259

4,672

Investment Funds Limited Partnerships Partially Owned Investment Companies Fair Value [Member]

2,355

1,737

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Other Investments [Member]

4,224

3,623

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]

21

15

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

77,963

78,939

933

937

3,171

3,561

1,014

1,034

Investment derivative instruments, assets

2,355

1,737

39

18

Other Derivative Instruments Fair Value

50

1

Separate Account Assets

2,978

2,734

Investment derivative instruments, liabilities

88,503

^[1]

88,961

^[2]

42

30

Other derivative instruments, liability

2

23

Liabilities, Fair Value Disclosure, Recurring

169

257

Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

2,939

3,129

874

893

1,750

2,309

424

466

Investment derivative instruments, assets

0

39

18

Other Derivative Instruments Fair Value

50

1

Separate Account Assets

2,862

2,635

Investment derivative instruments, liabilities

8,938

^[1]

9,451

^[2]

42

30

Other derivative instruments, liability

21

Liabilities, Fair Value Disclosure, Recurring

42

51

Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

73,509

74,602

0

1,409

1,252

326

305

2,355

1,737

Separate Account Assets

116

99

Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]

77,715

^[1]

77,995

^[2]

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

1,515

1,208

59

44

12

264

263

Other derivative instruments, liability

1,850

^[1]

1,515

^[2]

2

Liabilities, Fair Value Disclosure, Recurring

127

206

Fair Value, Measurements, Recurring [Member] | U.S. Treasury And Agency [Member] | Estimate of Fair Value Measurement [Member]

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | U.S. Treasury And Agency [Member] | Fair Value, Inputs, Level 1 [Member]

3,764

3,698

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | U.S. Treasury And Agency [Member] | Fair Value, Inputs, Level 2 [Member]

2,939

3,129

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Foreign [Member] | Estimate of Fair Value Measurement [Member]

825

569

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Foreign [Member] | Fair Value, Inputs, Level 2 [Member]

22,011

21,030

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Foreign [Member] | Fair Value, Inputs, Level 3 [Member]

21,759

20,937

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Corporate [Member] | Estimate of Fair Value Measurement [Member]

252

93

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Corporate [Member] | Fair Value, Inputs, Level 2 [Member]

24,485

23,996

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Corporate [Member] | Fair Value, Inputs, Level 3 [Member]

23,304

22,959

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Estimate of Fair Value Measurement [Member]

1,181

1,037

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]

15,483

15,290

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]

15,401

15,212

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | States, Municipalities, And Political Subdivisions [Member] | Estimate of Fair Value Measurement [Member]

82

78

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurements, Recurring [Member] | States, Municipalities, And Political Subdivisions [Member] | Fair Value, Inputs, Level 2 [Member]

12,220

14,925

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

12,220

14,925

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value

125

^[3]

$ 167

204

^[3]

$ 357

$ 466

$ 559

Guaranteed Minimum Income Benefit [Member] | Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value

125

^[5]

204

^[6]

Guaranteed Minimum Income Benefit [Member] | Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value

^[6]

$ 125

$ 204

[1]	(1) Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,224 million and other investments of $21 million at June 30, 2018 measured using NAV as a practical expedient.
[2]	(1) Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $3,623 million and other investments of $15 million at December 31, 2017 measured using NAV as a practical expedient.
[3]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $529 million at March 31, 2018, which includes a fair value derivative adjustment of $125 million and $167 million, respectively.
[4]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $774 million at March 31, 2017, which includes a fair value derivative adjustment of $357 million and $466 million, respectively.
[5]	(2) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.
[6]	(2) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.

Fair Value Measurements (Fair Value And Maximum Future Funding Commitments Related To Investments) (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Maximum future funding commitments	$ 3,441	$ 4,061
Fair Value	4,224	3,623
Financial [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Maximum future funding commitments	281	330
Fair Value	$ 569	$ 540
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	5 years	5 years
Financial [Member] \| Maximum [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	9 years	9 years
Real Assets [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Maximum future funding commitments	$ 192	$ 114
Fair Value	$ 673	$ 651
Real Assets [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
Real Assets [Member] \| Maximum [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	7 years	7 years
Distressed [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Maximum future funding commitments	$ 131	$ 141
Fair Value	$ 279	$ 289
Distressed [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
Distressed [Member] \| Maximum [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	7 years	7 years
Private Credit [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Maximum future funding commitments	$ 308	$ 327
Fair Value	$ 184	$ 187
Private Credit [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 [Member] \| Maximum [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	7 years	7 years
Traditional [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Maximum future funding commitments	$ 2,529	$ 3,149
Fair Value	$ 2,177	$ 1,656
Traditional [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
Traditional [Member] \| Maximum [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	15 years	15 years
Vintage [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 64	$ 30
Vintage [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 [Member] \| Maximum [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
Investment Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value	$ 278	$ 270

Fair Value Measurements (Schedule Of Significant Unobservable Inputs Used In Level 3 Liability Valuations) (Detail) - USD ($)
$ in Millions

6 Months Ended

Jun. 30, 2018

Mar. 31, 2018

^[2]

Dec. 31, 2017

Jun. 30, 2017

^[3]

Mar. 31, 2017

^[3]

Dec. 31, 2016

^[3]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value Measurements, Valuation Techniques

^[1]

Actuarial model

Minimum [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Long-Duration Contracts, Assumptions by Product and Guarantee, Lapse Rate

^[1]

3.00%

Significant Unobservable Inputs Annuitization Rate

^[1]

0.00%

Maximum [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Long-Duration Contracts, Assumptions by Product and Guarantee, Lapse Rate

^[1]

33.00%

Significant Unobservable Inputs Annuitization Rate

^[1]

100.00%

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value

$ 125

^[2]

$ 167

$ 204

^[2]

$ 357

$ 466

$ 559

Guaranteed Minimum Income Benefit [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value

^[4]

$ 125

$ 204

[1]	Discussion of the most significant inputs used in the fair value measurement of GLB and the sensitivity of those assumptions is included within Note 3 a) Guaranteed living benefits.
[2]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $529 million at March 31, 2018, which includes a fair value derivative adjustment of $125 million and $167 million, respectively.
[3]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $774 million at March 31, 2017, which includes a fair value derivative adjustment of $357 million and $466 million, respectively.
[4]	(2) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.

Fair Value Measurements (Assets Measured At Fair Value Using Significant Unobservable Inputs) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of Period, Assets	$ 64	$ 41	$ 44	$ 41
Transfers Into Level 3, Asset	0	0	0	0
Transfers out of Level 3, Assets	0	0	0	0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)	0	1	1	1
Net Realized Gains/ (Losses), Assets	(3)	0	(1)	0
Purchases, Assets	3	6	20	6
Sales, Assets	(5)	(9)	(5)	(9)
Settlements, Assets	0	0	0	0
Balance-End of Period, Assets	59	39	59	39
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(3)	0	(1)	0
Short-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of Period, Assets	12	21	0	25
Transfers Into Level 3, Asset	0	0	5	0
Transfers out of Level 3, Assets	0	0	0	0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0	0	0
Net Realized Gains/ (Losses), Assets	0	0	0	0
Purchases, Assets	1	7	9	14
Sales, Assets	0	0	0	0
Settlements, Assets	(1)	(21)	(2)	(32)
Balance-End of Period, Assets	12	7	12	7
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		0	0	0
Other Long-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of Period, Assets	270	233	263	225
Transfers Into Level 3, Asset	0	0	0	0
Transfers out of Level 3, Assets	0	0	0	0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)	0	(1)	2	3
Net Realized Gains/ (Losses), Assets	1	0	1	0
Purchases, Assets	16	16	30	24
Sales, Assets	0	0	0	0
Settlements, Assets	(23)	(5)	(32)	(9)
Balance-End of Period, Assets	264	243	264	243
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	1	0	1	0
Available-for-sale Securities [Member] \| Foreign Government Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of Period, Assets	176	80	93	74
Transfers Into Level 3, Asset	0	0	7	0
Transfers out of Level 3, Assets	0	0	0	0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)	(7)	3	2	2
Net Realized Gains/ (Losses), Assets	0	2	0	1
Purchases, Assets	95	19	182	33
Sales, Assets	(11)	(19)	(30)	(22)
Settlements, Assets	(1)	0	(2)	(3)
Balance-End of Period, Assets	252	85	252	85
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Available-for-sale Securities [Member] \| Corporate [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of Period, Assets	1,073	737	1,037	681
Transfers Into Level 3, Asset	6	28	6	57
Transfers out of Level 3, Assets	0	(13)	(10)	(67)
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)	(9)	0	(12)	(8)
Net Realized Gains/ (Losses), Assets	2	0	2	(1)
Purchases, Assets	217	65	356	221
Sales, Assets	(45)	(28)	(96)	(55)
Settlements, Assets	(63)	(42)	(102)	(81)
Balance-End of Period, Assets	1,181	747	1,181	747
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Available-for-sale Securities [Member] \| Collateralized Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of Period, Assets	83	45	78	45
Transfers Into Level 3, Asset	0	0	1	0
Transfers out of Level 3, Assets	0	0	0	0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0	0	0
Net Realized Gains/ (Losses), Assets	0	0	0	0
Purchases, Assets	0	0	4	1
Sales, Assets	0	0	0	(1)
Settlements, Assets	(1)	0	(1)	0
Balance-End of Period, Assets	82	45	82	45
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ 0	$ 0	$ 0	$ 0

Fair value measurements Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2018

Jun. 30, 2017

Jun. 30, 2018

Jun. 30, 2017

Mar. 31, 2018

Dec. 31, 2017

Mar. 31, 2017

Dec. 31, 2016

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Reported liabilities

$ 497

$ 684

^[1]

$ 497

$ 684

^[1]

$ 529

$ 550

$ 774

$ 853

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]

Balance - Beginning of Period, Liabilities

167

^[2]

466

^[3]

204

^[2]

559

^[3]

Transfers into level 3, liability

0

9

0

9

Transfers out of Level 3, Liabilities

0

Change in Net Unrealized Gains (Losses) included in OCI, Liabilities

0

Net Realized Gains/Losses, Liabilities

(42)

(118)

(79)

(211)

Purchases, Liabilities

0

Sales, Liabilities

0

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements

0

Balance - End of Period, Liabilities

125

^[2]

357

^[3]

125

^[2]

357

^[3]

Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)

(42)

(118)

(79)

(211)

Other Derivative Instruments Fair Value [Member]

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]

Balance - Beginning of Period, Liabilities

2

11

2

13

Transfers into level 3, liability

0

Transfers out of Level 3, Liabilities

0

(9)

0

(9)

Change in Net Unrealized Gains (Losses) included in OCI, Liabilities

0

Net Realized Gains/Losses, Liabilities

0

(2)

Purchases, Liabilities

0

Sales, Liabilities

0

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements

0

^[4]

Balance - End of Period, Liabilities

2

Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)

$ 0

$ (2)

[1]	(1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $853 million at December 31, 2016, which includes a fair value derivative adjustment of $357 million and $559 million, respectively.
[2]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $529 million at March 31, 2018, which includes a fair value derivative adjustment of $125 million and $167 million, respectively.
[3]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $684 million at June 30, 2017, and $774 million at March 31, 2017, which includes a fair value derivative adjustment of $357 million and $466 million, respectively.
[4]	(1) Purchases in Level 3 primarily consist of privately-placed fixed income securities.(2) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $497 million at June 30, 2018, and $550 million at December 31, 2017, which includes a fair value derivative adjustment of $125 million and $204 million, respectively.

Fair Value Measurements (Carrying Values And Fair Values Of Financial Instruments Not Measured At Fair Value) (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	$ 13,665	$ 14,474
Held-to-maturity Securities	13,860	14,335
Repurchase agreements	1,413	1,408
Short-term debt	600	1,013
Long-term debt	12,184	11,556
Trust preferred securities	308	308
Total liabilities	116,563	115,850
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	1,079	857
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
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	12,554	13,582
Repurchase agreements	1,413	1,408
Short-term Debt, Fair Value	615	1,013
Long-term Debt, Fair Value	12,296	12,332
Trust preferred securities	433	468
Total liabilities	14,757	15,221
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	32	35
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
U.S. Treasury And Agency [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	1,079	857
U.S. Treasury And Agency [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	54	58
U.S. Treasury And Agency [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Foreign [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Foreign [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	1,675	1,757
Foreign [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Corporate [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Corporate [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	2,633	3,184
Corporate [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	32	35
Collateralized Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Collateralized Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	2,585	2,742
Collateralized Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	0	0
States, Municipalities, And Political Subdivisions [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	0	0
States, Municipalities, And Political Subdivisions [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	5,607	5,841
States, Municipalities, And Political Subdivisions [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	0	0
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	13,665	14,474
Repurchase agreements	1,413	1,408
Short-term Debt, Fair Value	615	1,013
Long-term Debt, Fair Value	12,296	12,332
Trust preferred securities	433	468
Total liabilities	14,757	15,221
Estimate of Fair Value Measurement [Member] \| U.S. Treasury And Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	1,133	915
Estimate of Fair Value Measurement [Member] \| Foreign [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	1,675	1,757
Estimate of Fair Value Measurement [Member] \| Corporate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	2,665	3,219
Estimate of Fair Value Measurement [Member] \| Collateralized Mortgage Backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	2,585	2,742
Estimate of Fair Value Measurement [Member] \| States, Municipalities, And Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities, Fair Value	5,607	5,841
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities	13,860	14,335
Repurchase agreements	1,413	1,408
Short-term debt	600	1,013
Long-term debt	12,184	11,556
Trust preferred securities	308	308
Total liabilities	14,505	14,285
Reported Value Measurement [Member] \| U.S. Treasury And Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities	1,143	908
Reported Value Measurement [Member] \| Foreign [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities	1,678	1,738
Reported Value Measurement [Member] \| Corporate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities	2,736	3,159
Reported Value Measurement [Member] \| Collateralized Mortgage Backed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities	2,640	2,724
Reported Value Measurement [Member] \| States, Municipalities, And Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity Securities	$ 5,663	$ 5,806

Unpaid losses and loss expenses (RF) (Detail) - USD ($)
$ in Millions

6 Months Ended

Jun. 30, 2018

Jun. 30, 2017

Dec. 31, 2017

Dec. 31, 2016

Unpaid Losses and Loss Expenses [Roll Forward]

Gross unpaid losses and loss expenses, beginning of period

$ 63,179

$ 60,540

Reinsurance Recoverable on unpaid losses, beginning of period

^[1]

(14,014)

(12,708)

Net unpaid loss, beginning of period

49,165

47,832

Current Year Claims and Claims Adjustment Expense

9,026

8,396

PPD, Gross

^[2]

(437)

(461)

Total, Incurred

8,589

7,935

Net loss and loss expenses paid, Current Year

2,346

2,271

Net losses and loss expenses Paid, Prior Years

6,269

5,758

Total, Paid

8,615

8,029

Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Revaluation And Other

(96)

171

Net unpaid Loss, end of period

49,043

47,909

Reinsurance Recoverables on unpaid losses, end of period

^[3]

13,735

12,485

Gross unpaid losses and loss expenses, end of period

62,778

60,394

Reinsurance Recoverables, Allowance

319

335

$ 321

$ 300

prior period development, net adjustments

$ 37

$ 60

[1]	Net of provision for uncollectible reinsurance of $321 million and $300 million at December 31, 2017 and 2016, respectively.
[2]	Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments, and earned premiums totaling $37 million and $60 million for the six months ended June 30, 2018 and 2017, respectively.
[3]	Net of provision for uncollectible reinsurance of $319 million and $335 million at June 30, 2018 and 2017, respectively.

Unpaid losses and loss expenses Unpaid losses and loss expenses (PPD table) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	$ (191)	$ (170)	$ (400)	$ (401)
North America Commercial P&C Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(155)	(131)	(256)	(310)
North America Personal P&C Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	7	37	1	34
North American Agriculture Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	0	0	(76)	(79)
Overseas General Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(72)	(88)	(94)	(76)
Global Reinsurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(16)	(31)	(30)	(23)
Corporate Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	45	43	55	53
Long Tail [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(91)	(76)	(73)	(120)
Long Tail [Member] \| North America Commercial P&C Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(104)	(83)	(96)	(177)
Long Tail [Member] \| North America Personal P&C Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	0	0	0	0
Long Tail [Member] \| North American Agriculture Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	0	0	0	0
Long Tail [Member] \| Overseas General Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(2)	0	(2)	32
Long Tail [Member] \| Global Reinsurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(30)	(36)	(30)	(28)
Long Tail [Member] \| Corporate Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	45	43	55	53
Short Tail [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(100)	(94)	(327)	(281)
Short Tail [Member] \| North America Commercial P&C Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(51)	(48)	(160)	(133)
Short Tail [Member] \| North America Personal P&C Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	7	37	1	34
Short Tail [Member] \| North American Agriculture Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	0	0	(76)	(79)
Short Tail [Member] \| Overseas General Insurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	(70)	(88)	(92)	(108)
Short Tail [Member] \| Global Reinsurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	14	5	0	5
Short Tail [Member] \| Corporate Segment [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	$ 0	$ 0	$ 0	$ 0

Unpaid losses and loss expenses Unpaid losses and loss expenses (narrative)(Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	$ (191)	$ (170)	$ (400)	$ (401)
Prior period reclassification adjustments		(1)		(13)
non-A&E run-off [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	45		55
Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(91)	(76)	(73)	(120)
Prior period reclassification adjustments		(2)		3
Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(100)	(94)	(327)	(281)
Accident year 2017 [Member] \| Catastrophe [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(36)		(142)
North America Commercial P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(155)	(131)	(256)	(310)
North America Commercial P&C Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(104)	(83)	(96)	(177)
North America Commercial P&C Insurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(51)	(48)	(160)	(133)
North America Commercial P&C Insurance [Member] \| Surety [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse			(19)
North America Commercial P&C Insurance [Member] \| North America Workers' Compensation [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(118)	(75)	(138)	(79)
North America Commercial P&C Insurance [Member] \| Commercial Excess and Umbrella [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse			(29)
North America Commercial P&C Insurance [Member] \| Other [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse			(45)
North America Commercial P&C Insurance [Member] \| Accident year 2017 [Member] \| North America Workers' Compensation [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(56)
North America Commercial P&C Insurance [Member] \| Accident year 2017 [Member] \| Catastrophe [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse			(3)
North America Commercial P&C Insurance [Member] \| Accident year 2017 [Member] \| Catastrophe [Member] \| Commercial Property and Marine [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(40)		(115)
North America Commercial P&C Insurance [Member] \| Accident year 2015 and prior [Member] \| North America Workers' Compensation [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse		(38)
North America Commercial P&C Insurance [Member] \| Accident Year 2010 and Prior [Member] \| Commercial Excess and Umbrella [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse				(74)
North America Commercial P&C Insurance [Member] \| Accident years 2015 through 2017 [Member] \| Other [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	14		74
North America Commercial P&C Insurance [Member] \| Accident Year 2016 [Member] \| North America Workers' Compensation [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse		(57)
North America Commercial P&C Insurance [Member] \| Accident year 2012 and 2013 [Member] \| Professional Liability Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse				(25)
North America Commercial P&C Insurance [Member] \| Accident years 2014 and 2016 [Member] \| Property [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse		(45)		(57)
North America Commercial P&C Insurance [Member] \| Accident year 2015 and 2016 [Member] \| Accident and Health Insurance Product Line [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse				(19)
North America Commercial P&C Insurance [Member] \| Accident year 2015 [Member] \| Surety [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse				(45)
North America Personal [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	7		1
North America Personal [Member] \| Accident year 2017 [Member] \| Catastrophe [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(5)		(11)
North America Personal [Member] \| Accident Years 2012 - 2016 [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse		37		34
North America Agricultural Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	0	0	(76)	(79)
North America Agricultural Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	0	0	0	0
North America Agricultural Insurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	0	0	(76)	(79)
Overseas General Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(72)	(88)	(94)	(76)
Overseas General Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(2)	0	(2)	32
Overseas General Insurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(70)	(88)	(92)	(108)
Overseas General Insurance [Member] \| Personal lines [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(17)
Overseas General Insurance [Member] \| Accident and Health Insurance Product Line [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(16)
Overseas General Insurance [Member] \| Other [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(30)
Overseas General Insurance [Member] \| Accident year 2017 [Member] \| Catastrophe [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse			(12)
Overseas General Insurance [Member] \| Accident year 2013 - 2015 [Member] \| Property and Inland Marine [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse		(37)
Overseas General Insurance [Member] \| Accident years 2014 - 2016 [Member] \| Property and Inland Marine [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(40)
Overseas General Insurance [Member] \| Accident years 2014 - 2016 [Member] \| Energy and Technical Risk Property [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse		(26)
Overseas General Insurance [Member] \| Accident years 2014 - 2016 [Member] \| Accident and Health Insurance Product Line [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse		(19)
Overseas General Insurance [Member] \| Accident years 2016 and prior [Member] \| Casualty [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse				32
Global Reinsurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(16)	(31)	(30)	(23)
Global Reinsurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(30)
Global Reinsurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	14
Global Reinsurance [Member] \| Other [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse				(27)
Global Reinsurance [Member] \| Accident Year 2013 and prior [Member] \| Casualty & Professional [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(32)
Global Reinsurance [Member] \| Accident year 2017 [Member] \| Catastrophe [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	9		(1)
Global Reinsurance [Member] \| Accident year 2011 and prior [Member] \| Casualty & Professional [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse		(36)		(36)
Global Reinsurance [Member] \| Accident year 2015 [Member] \| Auto Liability Excess Lines [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse				9
Global Reinsurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(16)	(31)	(30)	(23)
Global Reinsurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(30)	(36)	(30)	(28)
Global Reinsurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	14	5	0	5
Corporate Segment [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	45	43	55	53
Corporate Segment [Member] \| non-A&E run-off [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse				35
Corporate Segment [Member] \| Discontinued Operations [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	10	8	20	18
Corporate Segment [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	45	43	55	53
Corporate Segment [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	0	$ 0	0	$ 0
All segments excluding Corporate [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(236)		(455)
All segments excluding Corporate [Member] \| Excluding Catastrophic Events [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	(64)		(188)
All segments excluding Corporate [Member] \| Accident years 2014 and prior [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
PPD (Favorable) / Adverse	$ (136)		$ (125)

Debt (Detail) € in Millions, $ in Millions	3 Months Ended	6 Months Ended
Debt (Detail) € in Millions, $ in Millions	Jun. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2018 EUR (€)
INA Senior Note Due June 2019 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 500	$ 500
Debt Instrument, Interest Rate, Stated Percentage	5.90%	5.90%
Debt, Current	$ 499	$ 499
Chubb INA Senior Notes Due 2037 [Member] \| Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 1,000	$ 1,000
Debt Instrument, Interest Rate, Stated Percentage	6.375%	6.375%
Gain (Loss) on Extinguishment of Debt	$ (36)	$ (36)
Senior Notes [Member] \| INA Senior Note Due March 2028 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 1,100	€ 900
Debt Instrument, Interest Rate, Stated Percentage			1.55%	1.55%
Make Whole Premium Additional Percent			0.15%	0.15%
Senior Notes [Member] \| INA Senior Note Due March 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 1,100	€ 900
Debt Instrument, Interest Rate, Stated Percentage			2.50%	2.50%
Make Whole Premium Additional Percent			0.25%	0.25%
Senior Notes [Member] \| INA Senior Notes Due March 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 300
Debt Instrument, Interest Rate, Stated Percentage			5.80%	5.80%
Senior Notes [Member] \| INA Senior Note Due May 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 600	$ 600
Debt Instrument, Interest Rate, Stated Percentage	5.75%	5.75%

Commitments, Contingencies, And Guarantees (Narrative) (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Financial Instruments Owned and Pledged as Collateral [Line Items]
Derivative asset subject to a master netting agreement	$ 53
Derivative liability subject to a master netting agreement		$ 24
Repurchase agreements	1,413	$ 1,408
Purchase Commitment, Remaining Minimum Amount Committed	948
Carrying value of limited partnerships and partially-owned investment companies included in other investments	3,900
Funding commitments relating to limited partnerships and partially-owned investment companies	3,400
Unrecognized tax benefits	$ 14

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

Jun. 30, 2018

Dec. 31, 2017

Foreign currency forward contracts

Cross Currency Swap [Member]

$ 2,364

$ 2,064

Options/Futures contracts on notes and bonds

45

Convertible securities [Member]

1,409

1,007

Investment And Embedded Derivative Instruments [Member]

10

6

^[1]

3,828

3,122

Future contracts on equities [Member]

48

23

Other Derivatives [Member]

^[2]

1,632

1,553

Other Derivative Instruments [Member]

351

75

1,983

1,628

^[3]

1,163

1,083

Fixed Maturities [Member] | Convertible securities [Member]

^[3]

0

Equity [Member] | Convertible securities [Member]

9

5

Other Assets [Member] | Foreign currency forward contracts

0

Other Assets [Member] | Cross Currency Swap [Member]

33

14

Other Assets [Member] | Options/Futures contracts on notes and bonds

0

Other Assets [Member] | Future contracts on equities [Member]

6

4

Other Assets [Member] | Other Derivatives [Member]

^[2]

32

0

Other Assets [Member] | Other Derivative Instruments [Member]

18

1

Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Foreign currency forward contracts

50

1

Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Cross Currency Swap [Member]

(36)

(27)

Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Options/Futures contracts on notes and bonds

0

Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Investment And Embedded Derivative Instruments [Member]

(6)

(3)

Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Future contracts on equities [Member]

(42)

(30)

Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivatives [Member]

^[2]

0

(21)

Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivative Instruments [Member]

(2)

Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Guaranteed Minimum Income Benefit [Member]

(2)

(23)

Derivative Instruments, Gain (Loss) [Line Items]

^[3]

$ (497)

$ (550)

[1]	Includes fair value of embedded derivatives.
[2]	Related to GMDB and GLB blocks of business.
[3]	Includes both future policy benefits reserves and fair value derivative adjustment. 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 (Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations) (Detail) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2018

Jun. 30, 2017

Jun. 30, 2018

Jun. 30, 2017

Foreign currency forward contracts

$ 29

$ 63

$ 108

$ 90

Derivative Instruments, Gain (Loss) [Line Items]

All Other Futures Contracts And Options [Member]

3

(7)

7

Derivative Instruments, Gain (Loss) [Line Items]

Investment And Embedded Derivative Instruments [Member]

21

(9)

34

(17)

Derivative Instruments, Gain (Loss) [Line Items]

24

(16)

41

(10)

Derivative Instruments, Gain (Loss) [Line Items]

Future contracts on equities [Member]

^[1]

41

118

79

211

Derivative Instruments, Gain (Loss) [Line Items]

Other Derivatives [Member]

^[2]

(44)

(38)

(22)

(112)

Derivative Instruments, Gain (Loss) [Line Items]

Guaranteed Living Benefit And Other Derivative Instruments [Member]

8

(1)

10

1

Derivative Instruments, Gain (Loss) [Line Items]

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

$ 5

$ 79

$ 67

$ 100

[1]	Excludes foreign exchange gains (losses) related to GLB.
[2]	Related to GMDB and GLB blocks of business.

Commitments, contingencies, and guarantees Commitments, Contingencies, And Guarantees (Transactions accounted for as secured borrowings) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	$ 2,355	$ 1,737
Securities lending payable	2,355	1,737
Cash and Cash Equivalents [Member] \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	990	828
U.S. Treasury And Agency [Member] \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	100	36
Foreign Government Debt [Member] \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	909	712
Corporate [Member] \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	14	0
Collateralized Mortgage Backed Securities [Member] \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	55	74
Equity Securities [Member] \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	$ 287	$ 87

Commitments, contingencies, and guarantees Commitments, Contingencies, And Guarantees (Collateral pledged under repurchase agreements) (Details) - USD ($)
$ in Millions

Jun. 30, 2018

Dec. 31, 2017

$ 1,449

$ 1,434

U.S. Treasury And Agency [Member]

1,413

1,408

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

Collateralized Mortgage Backed Securities [Member]

254

239

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

Repurchase Agreements [Member]

1,195

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

Secured Borrowings, Gross, Difference, Amount

^[1]

36

26

Maturity Less than 30 Days [Member]

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

Maturity Less than 30 Days [Member] | U.S. Treasury And Agency [Member]

578

378

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

Maturity Less than 30 Days [Member] | Collateralized Mortgage Backed Securities [Member]

245

9

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

Maturity Greater than 90 Days [Member]

333

369

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

Maturity Greater than 90 Days [Member] | U.S. Treasury And Agency [Member]

871

1,056

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

Maturity Greater than 90 Days [Member] | Collateralized Mortgage Backed Securities [Member]

9

230

Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]

$ 862

$ 826

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

Share-Based Compensation (Detail) - $ / shares		6 Months Ended
Share-Based Compensation (Detail) - $ / shares	Feb. 22, 2018	Jun. 30, 2018
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period in years		3 years
Award term period in years		10 years
Stock options granted	1,841,329
Weighted-average grant date fair value for stock options granted	$ 29.71
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period in years		4 years
Restricted stock awards granted to employees and officers of the company	973,624
Grant date fair value of awards except for options granted to employees and officers of the company	$ 143.07
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period in years		3 years
Restricted stock awards granted to employees and officers of the company	180,065
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted to employees and officers of the company	301,024

Shareholders' equity (Details) $ / shares in Units, $ in Millions	Jun. 30, 2018 SFr / shares shares	May 31, 2018 $ / shares	Dec. 31, 2017 SFr / shares shares	Dec. 21, 2017 USD ($)	May 31, 2017 $ / shares	Nov. 30, 2016 USD ($)	May 31, 2016 $ / shares
Equity, Class of Treasury Stock [Line Items]
Common Shares, par value \| SFr / shares	SFr 24.15		SFr 24.15
Annual dividend per share approved by shareholders \| $ / shares		$ 2.92			$ 2.84		$ 2.76
Common Shares in treasury, shares \| shares	16,281,700		15,950,685
Common Stock, Dividend Rate Approved \| $ / shares		$ 0.73			$ 0.71		$ 0.69
Dec 2017 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Authorized amount of share repurchase program \| $				$ 1,000
Nov 2016 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Authorized amount of share repurchase program \| $						$ 1,000

Shareholders' equity Dividends Declared (Details)	3 Months Ended				6 Months Ended
Shareholders' equity Dividends Declared (Details)	Jun. 30, 2018 $ / shares	Jun. 30, 2018 SFr / shares	Jun. 30, 2017 $ / shares	Jun. 30, 2017 SFr / shares	Jun. 30, 2018 $ / shares	Jun. 30, 2018 SFr / shares	Jun. 30, 2017 $ / shares	Jun. 30, 2017 SFr / shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Common Stock, Dividends, Per Share, Declared \| (per share)	$ 0.73	SFr 0.73	$ 0.71	SFr 0.69	$ 1.44	SFr 1.39	$ 1.40	SFr 1.38

Shareholders' equity Share Repurchases (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Nov 2016 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased			2,381,566		3,417,630
Cost of shares repurchased			$ 335		$ 475
Repurchase authorization remaining at end of period			$ 525		$ 525
2018 Stock Repurchase Plan [Member] [Domain]
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased		2,443,855		2,443,855
Cost of shares repurchased		$ 324		$ 324
Repurchase authorization remaining at end of period		$ 676		$ 676
Subsequent Event [Member] \| 2018 Stock Repurchase Plan [Member] [Domain]
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased	740,869
Cost of shares repurchased	$ 100
Repurchase authorization remaining at end of period	$ 576

Postretirement benefits Components of net periodic benefit costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Plan [Member] \| UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 15	$ 16	$ 29	$ 32
Interest cost	27	26	53	52
Expected return on plan assets	(53)	(48)	(106)	(95)
Amortization of net actuarial loss	0	0	0	0
Amortization of prior service cost	0	0	0	0
Curtailments	0	0	0	0
Settlement	1	0	1	0
Net periodic (benefit) cost	(10)	(6)	(23)	(11)
Pension Plan [Member] \| Non-US [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	3	4	6	8
Interest cost	7	7	14	14
Expected return on plan assets	(13)	(10)	(26)	(20)
Amortization of net actuarial loss	0	1	0	1
Amortization of prior service cost	0	0	0	0
Curtailments	0	(8)	0	(8)
Settlement	0	0	0	0
Net periodic (benefit) cost	(3)	(6)	(6)	(5)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	2	0	2
Interest cost	1	0	2	1
Expected return on plan assets	(1)	(1)	(2)	(2)
Amortization of net actuarial loss	0	0	0	0
Amortization of prior service cost	(22)	(23)	(43)	(46)
Curtailments	(1)	0	(1)	0
Settlement	0	0	0	0
Net periodic (benefit) cost	$ (23)	$ (22)	$ (44)	$ (45)

Segment information Segment Information (narrative Detail (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Gain (Loss) on Derivative	$ 29	$ 63	$ 108	$ 90
Net investment income	828	770	1,634	1,515
North America Agricultural Insurance [Member]
Segment Reporting Information [Line Items]
Segment Income Loss Including Gains Losses On Crop Derivatives	43
Gain (Loss) on Derivative	8
Net investment income	6	6	13	12
Segment Life [Member]
Segment Reporting Information [Line Items]
Net investment income	85	$ 77	$ 168	$ 152
Management Underwriting Income (Loss)	75
Gains(Losses) On Fair Value Changes In Separate Account Assets	$ (10)

Segment Information (Operations By Segment) (Detail) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2018

Jun. 30, 2017

Jun. 30, 2018

Jun. 30, 2017

$ 8,015

$ 7,581

$ 15,119

$ 14,291

7,664

7,237

14,691

14,009

4,487

4,146

8,589

7,935

150

163

301

331

1,464

1,449

2,928

2,846

747

706

1,439

1,382

816

773

1,434

1,515

828

770

1,634

1,515

(115)

(145)

(162)

(215)

85

65

170

129

Net realized gains (losses) including OTTI

1,674

1,623

3,060

3,116

18

101

16

94

Interest expense

167

147

324

301

Chubb integration expenses

13

72

23

183

Income tax expense

218

200

353

328

Net income

1,294

1,305

2,376

2,398

Prior Period Reclassification Adjustment

1

13

North America Commercial P&C Insurance [Member]

3,331

3,203

^[1]

6,143

5,933

^[2]

3,277

3,099

6,306

6,140

2,084

1,936

3,992

3,796

0

448

464

920

951

253

241

484

472

492

458

910

921

510

490

1,013

968

(13)

(4)

(19)

0

0

North America Personal P&C Insurance [Member]

1,015

952

1,942

1,889

1,335

1,255

2,383

2,239

1,156

1,093

2,296

2,179

728

683

1,614

1,316

0

228

230

465

447

68

66

133

131

132

114

84

285

59

56

118

111

1

2

3

5

6

8

North America Agricultural Insurance [Member]

187

164

195

386

388

403

496

464

351

344

394

358

289

290

236

217

0

26

27

25

26

1

2

(2)

(3)

35

25

135

118

6

13

12

1

7

14

Overseas General Insurance [Member]

33

23

133

115

2,199

2,007

^[1]

4,583

4,219

^[2]

2,161

2,018

4,268

3,954

1,071

964

2,149

2,035

0

584

555

1,172

1,084

266

243

505

488

240

256

442

347

155

148

306

296

(12)

(3)

(5)

(4)

11

21

22

Global Reinsurance [Member]

396

732

625

197

190

390

389

167

168

335

357

83

46

150

140

0

40

43

80

94

9

12

19

22

35

67

86

101

65

129

127

(6)

1

(13)

1

0

106

131

228

227

Life Insurance [Member]

565

523

1,124

1,047

552

515

1,092

1,021

184

182

389

375

150

163

301

331

138

130

266

244

80

77

158

149

0

(37)

(22)

(78)

85

77

168

152

8

(12)

4

(41)

0

1

Corporate Segment [Member]

77

52

141

114

0

0

48

45

59

56

0

0

70

65

142

123

(118)

(110)

(201)

(179)

(52)

(72)

(113)

(151)

(94)

(129)

(131)

(174)

64

42

128

84

Net realized gains (losses) including OTTI

(140)

(95)

(311)

(240)

18

101

16

94

Interest expense

167

147

324

301

Chubb integration expenses

13

72

23

183

Income tax expense

218

200

353

328

Net income

$ (520)

$ (413)

$ (995)

$ (958)

[1]	The 2017 net premiums written amount was revised to reflect the transfer of certain multinational accounts ($1 million) from the North America Commercial P&C Insurance segment to the Overseas General Insurance segment to better align the reporting with the management of these businesses in 2018. There is no impact on a consolidated basis.
[2]	The 2017 net premiums written amount was revised to reflect the transfer of certain multinational accounts ($13 million) from the North America Commercial P&C Insurance segment to the Overseas General Insurance segment to better align the reporting with the management of these businesses in 2018. There is no impact on a consolidated basis.

Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 1,294	$ 1,305	$ 2,376	$ 2,398
Weighted-average shares outstanding	465,276,597	467,981,077	465,488,724	468,244,458
Share-based compensation plans	3,103,727	3,872,860	3,489,013	3,900,678
Weighted-average shares outstanding and assumed conversions	468,380,324	471,853,937	468,977,737	472,145,136
Basic earnings per share (US$ per share)	$ 2.78	$ 2.79	$ 5.10	$ 5.12
Diluted earnings per share (US$ per share)	$ 2.76	$ 2.77	$ 5.07	$ 5.08
Potential anti-dilutive share conversions	3,814,491	2,066,578	3,305,735	1,467,556

Information provided in connection with outstanding debt of subsidiaries Information provided in connection with outstanding debt of subsidiaries (Narrative) (Details)	Jun. 30, 2018
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]
Equity Method Investment, Ownership Percentage	100.00%

Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Balance Sheet) (Detail) - USD ($)
$ in Millions

Jun. 30, 2018

Dec. 31, 2017

Jun. 30, 2017

Dec. 31, 2016

Condensed Balance Sheet Statements, Captions [Line Items]

$ 101,186

$ 102,444

1,000

^[1]

728

^[2]

^[1]

101

123

10,341

9,334

14,792

15,034

204

184

311

326

21,759

22,054

0

0

17,840

16,795

167,534

167,022

62,778

63,179

$ 60,394

$ 60,540

15,748

15,216

5,470

5,321

0

0

1,413

1,408

600

1,013

12,184

11,556

308

18,062

17,849

116,563

115,850

50,971

51,172

$ 50,349

Chubb Limited (Parent Guarantor)

167,534

167,022

Condensed Balance Sheet Statements, Captions [Line Items]

0

1

^[1]

3

^[2]

^[1]

0

0

0

0

0

0

42,919

41,909

8,686

9,639

2

3

51,608

51,554

0

0

0

0

403

^[1]

0

^[2]

0

0

0

0

234

382

637

382

50,971

51,172

Chubb INA Holdings Inc (Subsidiary Issuer)

51,608

51,554

Condensed Balance Sheet Statements, Captions [Line Items]

172

168

1

^[1]

1

^[2]

^[1]

0

0

0

0

0

0

51,706

51,165

0

655

287

52,534

51,621

0

0

0

8,943

9,432

837

^[1]

115

^[2]

0

600

1,013

12,173

11,546

308

2,248

1,411

25,109

23,825

27,425

27,796

Other Chubb Limited Subsidiaries

52,534

51,621

Condensed Balance Sheet Statements, Captions [Line Items]

101,014

102,276

2,238

^[1]

839

^[2]

^[1]

101

123

11,297

10,820

27,117

27,514

1,127

1,194

311

326

21,759

22,054

0

257

0

18,760

20,578

183,981

185,724

73,427

74,767

16,815

18,875

6,393

6,331

0

207

0

^[1]

0

^[2]

1,413

1,408

0

11

10

0

18,722

18,848

116,781

120,446

67,200

65,278

Consolidating Adjustments and Eliminations

183,981

185,724

Condensed Balance Sheet Statements, Captions [Line Items]

0

(1,240)

^[1]

(115)

^[2]

^[1]

0

(956)

(1,486)

(12,325)

(12,480)

(923)

(1,010)

0

0

(94,625)

(93,074)

(8,943)

(9,639)

(1,577)

(4,073)

(120,589)

(121,877)

(10,649)

(11,588)

(1,067)

(3,659)

(923)

(1,010)

(8,943)

(9,639)

(1,240)

^[1]

(115)

^[2]

0

0

0

0

(3,142)

(2,792)

(25,964)

(28,803)

(94,625)

(93,074)

Condensed Cash Flow Statements, Captions [Line Items]

$ (120,589)

$ (121,877)

[1]

Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 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. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Operations) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Statement of Income Captions [Line Items]
Net premiums written	$ 8,015	$ 7,581	$ 15,119	$ 14,291
Net premiums earned	7,664	7,237	14,691	14,009
Net investment income	828	770	1,634	1,515
Income (Loss) from Subsidiaries, Net of Tax	0	0	0	0
Net realized gains (losses) including OTTI	18	101	16	94
Losses and loss expenses	4,487	4,146	8,589	7,935
Policy benefits	150	163	301	331
Policy acquisition costs and administrative expenses	2,211	2,155	4,367	4,228
Interest (income) expense	167	147	324	301
Other (income) expense	(115)	(145)	(162)	(215)
Amortization of purchased intangibles	85	65	170	129
Chubb integration expenses	13	72	23	183
Income tax expense	218	200	353	328
Net income	1,294	1,305	2,376	2,398
Comprehensive income (loss)	277	1,675	730	3,082
Consolidating Adjustments and Eliminations
Condensed Statement of Income Captions [Line Items]
Net premiums written	0	0	0	0
Net premiums earned	0	0	0	0
Net investment income	0	0	0	0
Income (Loss) from Subsidiaries, Net of Tax	(1,695)	(1,918)	(3,602)	(3,646)
Net realized gains (losses) including OTTI	0	0	0	0
Losses and loss expenses	0	0	0	0
Policy benefits	0	0	0	0
Policy acquisition costs and administrative expenses	0	0	0	0
Interest (income) expense	0	0	0	0
Other (income) expense	0	0	0	0
Amortization of purchased intangibles	0	0	0	0
Chubb integration expenses	0	0	0	0
Income tax expense	0	0	0	0
Net income	(1,695)	(1,918)	(3,602)	(3,646)
Comprehensive income (loss)	110	(2,676)	(720)	(5,005)
Chubb Limited (Parent Guarantor)
Condensed Statement of Income Captions [Line Items]
Net premiums written	0	0	0	0
Net premiums earned	0	0	0	0
Net investment income	1	2	3	2
Income (Loss) from Subsidiaries, Net of Tax	1,241	1,253	2,263	2,280
Net realized gains (losses) including OTTI	2	(2)	0	(2)
Losses and loss expenses	0	0	0	0
Policy benefits	0	0	0	0
Policy acquisition costs and administrative expenses	23	18	41	36
Interest (income) expense	(76)	(84)	(156)	(168)
Other (income) expense	(4)	4	(9)	(2)
Amortization of purchased intangibles	0	0	0	0
Chubb integration expenses	2	6	4	6
Income tax expense	5	4	10	10
Net income	1,294	1,305	2,376	2,398
Comprehensive income (loss)	277	1,675	730	3,082
Chubb INA Holdings Inc (Subsidiary Issuer)
Condensed Statement of Income Captions [Line Items]
Net premiums written	0	0	0	0
Net premiums earned	0	0	0	0
Net investment income	5	4	9	7
Income (Loss) from Subsidiaries, Net of Tax	454	665	1,339	1,366
Net realized gains (losses) including OTTI	73	(1)	49	(14)
Losses and loss expenses	0	0	0	0
Policy benefits	0	0	0	0
Policy acquisition costs and administrative expenses	19	(2)	41	12
Interest (income) expense	204	212	413	433
Other (income) expense	8	10	16	25
Amortization of purchased intangibles	0	0	0	0
Chubb integration expenses	0	4	1	53
Income tax expense	(36)	(87)	(95)	(199)
Net income	337	531	1,021	1,035
Comprehensive income (loss)	(462)	920	(246)	1,711
Other Chubb Limited Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net premiums written	8,015	7,581	15,119	14,291
Net premiums earned	7,664	7,237	14,691	14,009
Net investment income	822	764	1,622	1,506
Income (Loss) from Subsidiaries, Net of Tax	0	0	0	0
Net realized gains (losses) including OTTI	(57)	104	(33)	110
Losses and loss expenses	4,487	4,146	8,589	7,935
Policy benefits	150	163	301	331
Policy acquisition costs and administrative expenses	2,169	2,139	4,285	4,180
Interest (income) expense	39	19	67	36
Other (income) expense	(119)	(159)	(169)	(238)
Amortization of purchased intangibles	85	65	170	129
Chubb integration expenses	11	62	18	124
Income tax expense	249	283	438	517
Net income	1,358	1,387	2,581	2,611
Comprehensive income (loss)	$ 352	$ 1,756	$ 966	$ 3,294

Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Cash Flows) (Detail) - USD ($)
$ in Millions

6 Months Ended

Jun. 30, 2018

Jun. 30, 2017

$ 2,197

$ 1,640

(12,297)

(12,260)

(337)

(212)

(85)

(82)

6,858

6,873

Maturities and redemptions of fixed maturities available for sale

83

104

3,920

5,169

Maturities and redemptions of fixed maturities held to maturity

732

408

401

354

5

(129)

(813)

(345)

413

487

0

Net cash flows from (used for) investing activities

(140)

(244)

(1,260)

123

(661)

(646)

(347)

(475)

2,171

0

(1,900)

(500)

1,014

1,343

(1,009)

(1,338)

60

89

0

0

Net proceeds from (payments to) affiliated notional cash pooling program

0

0

192

209

(169)

(125)

Effect of foreign currency rate changes on cash and restricted cash

(649)

(1,443)

(38)

11

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

250

331

851

1,088

Chubb Limited (Parent Guarantor)

1,101

1,419

Condensed Cash Flow Statements, Captions [Line Items]

43

551

0

0

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

0

(750)

Net cash flows from (used for) investing activities

0

(750)

0

(661)

(646)

0

0

0

0

0

0

0

963

264

Net proceeds from (payments to) affiliated notional cash pooling program

0

403

^[1]

(170)

^[2]

0

0

Effect of foreign currency rate changes on cash and restricted cash

705

(552)

0

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

(2)

(1)

3

1

Chubb INA Holdings Inc (Subsidiary Issuer)

1

0

Condensed Cash Flow Statements, Captions [Line Items]

3,042

1,444

(22)

(5)

0

0

0

Maturities and redemptions of fixed maturities available for sale

0

14

13

Maturities and redemptions of fixed maturities held to maturity

0

6

166

(8)

(7)

0

0

(3,500)

Net cash flows from (used for) investing activities

(7)

2

(3,517)

169

0

0

2,171

(1,900)

(500)

0

0

0

0

(518)

(328)

Net proceeds from (payments to) affiliated notional cash pooling program

0

722

^[1]

(619)

^[2]

0

0

Effect of foreign currency rate changes on cash and restricted cash

475

(1,447)

0

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

0

166

1

Other Chubb Limited Subsidiaries

1

167

Condensed Cash Flow Statements, Captions [Line Items]

2,187

1,686

(12,275)

(12,255)

(337)

(212)

(85)

(82)

6,858

6,873

Maturities and redemptions of fixed maturities available for sale

83

104

3,906

5,156

Maturities and redemptions of fixed maturities held to maturity

732

408

395

188

13

(122)

(813)

(345)

413

487

0

Net cash flows from (used for) investing activities

(133)

(246)

(1,243)

(46)

0

(347)

(475)

0

0

1,014

1,343

(1,009)

(1,338)

60

89

(3,075)

(2,041)

(445)

64

Net proceeds from (payments to) affiliated notional cash pooling program

4,250

0

^[1]

0

^[2]

192

209

(169)

(125)

Effect of foreign currency rate changes on cash and restricted cash

471

(2,274)

(38)

11

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

1,377

(623)

962

2,068

Consolidation, Eliminations [Member]

2,339

1,445

Condensed Cash Flow Statements, Captions [Line Items]

(3,075)

(2,041)

0

0

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

0

4,250

Net cash flows from (used for) investing activities

0

4,250

0

0

0

0

0

0

0

0

3,075

2,041

0

Net proceeds from (payments to) affiliated notional cash pooling program

(4,250)

(1,125)

^[1]

789

^[2]

0

0

Effect of foreign currency rate changes on cash and restricted cash

(2,300)

2,830

0

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

(1,125)

789

(115)

(982)