a) Fixed maturities


March 31, 2021	Amortized Cost		Valuation Allowance		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	2,413	$	—	$	121	$	(7)	$	2,527
Non-U.S.	25,147		(6)		1,214		(189)		26,166
Corporate and asset-backed securities	35,224		(9)		1,474		(289)		36,400
Mortgage-backed securities	18,788		—		738		(89)		19,437
Municipal	6,301		—		254		(14)		6,541
	$	87,873	$	(15)	$	3,801	$	(588)	$	91,071
	Amortized Cost		Valuation Allowance		Net Carrying Value		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value

Held to maturity
U.S. Treasury / Agency	$	1,158	$	—	$	1,158	$	39	$	—	$	1,197
Non-U.S.	1,276		(6)		1,270		82		(1)		1,351
Corporate and asset-backed securities	2,163		(35)		2,128		183		—		2,311
Mortgage-backed securities	1,888		(1)		1,887		110		—		1,997
Municipal	4,690		(1)		4,689		207		—		4,896
	$	11,175	$	(43)	$	11,132	$	621	$	(1)	$	11,752


December 31, 2020	Amortized Cost		Valuation Allowance		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	2,471	$	—	$	199	$	—	$	2,670
Non-U.S.	24,594		(6)		1,808		(42)		26,354
Corporate and asset-backed securities	34,095		(14)		2,322		(72)		36,331
Mortgage-backed securities	17,456		—		1,022		(8)		18,470
Municipal	6,572		—		304		(2)		6,874
	$	85,188	$	(20)	$	5,655	$	(124)	$	90,699
	Amortized Cost		Valuation Allowance		Net Carrying Value		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value

Held to maturity
U.S. Treasury / Agency	$	1,392	$	—	$	1,392	$	60	$	—	$	1,452
Non-U.S.	1,295		(7)		1,288		118		(1)		1,405
Corporate and asset-backed securities	2,185		(35)		2,150		288		—		2,438
Mortgage-backed securities	2,000		(1)		1,999		148		(1)		2,146
Municipal	4,825		(1)		4,824		245		—		5,069
	$	11,697	$	(44)	$	11,653	$	859	$	(2)	$	12,510

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


	March 31, 2021				December 31, 2020
(in millions of U.S. dollars, except for percentages)	Amortized cost		% of Total		Amortized cost		% of Total
AAA	$	2,404	22	%	$	2,511	22	%
AA	5,815		52	%	6,193		53	%
A	2,109		19	%	2,138		18	%
BBB	818		7	%	826		7	%
BB	28		—	%	28		—	%
Other	1		—	%	1		—	%
Total	$	11,175	100	%	$	11,697	100	%

The following table presents fixed maturities by contractual maturity:


			March 31				December 31
			2021				2020
(in millions of U.S. dollars)	Net Carrying Value		Fair Value		Net Carrying Value		Fair Value
Available for sale
Due in 1 year or less	$	4,767	$	4,767	$	4,760	$	4,760
Due after 1 year through 5 years	26,100		26,100		26,227		26,227
Due after 5 years through 10 years	27,394		27,394		27,232		27,232
Due after 10 years	13,373		13,373		14,010		14,010
	71,634		71,634		72,229		72,229
Mortgage-backed securities	19,437		19,437		18,470		18,470
	$	91,071	$	91,071	$	90,699	$	90,699
Held to maturity
Due in 1 year or less	$	1,099	$	1,109	$	1,231	$	1,240
Due after 1 year through 5 years	3,471		3,613		3,592		3,760
Due after 5 years through 10 years	2,918		3,072		3,029		3,228
Due after 10 years	1,757		1,961		1,802		2,136
	9,245		9,755		9,654		10,364
Mortgage-backed securities	1,887		1,997		1,999		2,146
	$	11,132	$	11,752	$	11,653	$	12,510

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

b) Gross unrealized loss

Fixed maturities in an unrealized loss position at March 31, 2021 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 AFS fixed maturities in an unrealized loss position (including securities on loan) that are not deemed to have expected credit losses, the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position:


	0 – 12 Months				Over 12 Months				Total
March 31, 2021	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)
U.S. Treasury / Agency	$	220	$	(7)	$	—	$	—	$	220	$	(7)
Non-U.S.	4,775		(161)		381		(19)		5,156		(180)
Corporate and asset-backed securities	6,753		(254)		737		(19)		7,490		(273)
Mortgage-backed securities	5,470		(87)		62		(2)		5,532		(89)
Municipal	367		(13)		14		(1)		381		(14)
Total AFS fixed maturities	$	17,585	$	(522)	$	1,194	$	(41)	$	18,779	$	(563)


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

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

c) Net realized gains (losses)

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


	Three Months Ended
	March 31
(in millions of U.S. dollars)	2021		2020
Fixed maturities:



Gross realized gains	$	37	$	77
Gross realized losses	(19)		(125)
Net (provision for) recovery of expected credit losses	6		(150)
Impairment (1)	—		(121)
Total fixed maturities	$	24	$	(319)
Equity securities	367		(29)

Other investments	38		5
Foreign exchange gains (losses)	76		(68)
Investment and embedded derivative instruments	109		15
Fair value adjustments on insurance derivative	319		(685)
S&P futures	(44)		125
Other derivative instruments	(1)		(2)
Other	(1)		—
Net realized gains (losses) (pre-tax)	$	887	$	(958)

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

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


							Three Months Ended
							March 31
	2021						2020
(in millions of U.S. dollars)	Equity Securities		Other Investments		Total		Equity Securities		Other Investments		Total
Net gains (losses) recognized during the period	$	367	$	38	$	405	$	(29)	$	5	$	(24)
Less: Net gains (losses) recognized from sales of securities	45		—		45		(24)		—		(24)
Unrealized gains (losses) recognized for securities still held at reporting date	$	322	$	38	$	360	$	(5)	$	5	$	—

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


	Three Months Ended
			March 31
(in millions of U.S. dollars)	2021		2020
Available for sale
Valuation allowance for expected credit losses - beginning of period	$	20	$	—
Impact of adoption of new accounting guidance	—		25
Provision for expected credit loss	4		149
Initial allowance for purchased securities with credit deterioration	—		2


Recovery of expected credit loss	(9)		—
Valuation allowance for expected credit losses - end of period	$	15	$	176
Held to maturity
Valuation allowance for expected credit losses - beginning of period	$	44	$	—
Impact of adoption of new accounting guidance	—		44
Provision for expected credit loss	—		1


Recovery of expected credit loss	(1)		—
Valuation allowance for expected credit losses - end of period	$	43	$	45

d) Alternative investments

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


				March 31				December 31
	Expected Liquidation Period of Underlying Assets			2021				2020
(in millions of U.S. dollars)		Fair Value		Maximum Future Funding Commitments		Fair Value		Maximum Future Funding Commitments
Financial	2 to 10 Years	$	710	$	270	$	673	$	237
Real Assets	2 to 11 Years	942		621		805		598
Distressed	2 to 8 Years	481		864		358		970
Private Credit	3 to 8 Years	86		276		88		270
Traditional	2 to 14 Years	4,912		1,039		4,519		1,125
Vintage	1 to 2 Years	72		—		73		—
Investment funds	Not Applicable	254		—		254		—
		$	7,457	$	3,070	$	6,770	$	3,200

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


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

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

e) Restricted assets

Chubb is required to maintain assets on deposit with various regulatory authorities to support its insurance and reinsurance operations. These requirements are generally promulgated in the statutory regulations of the individual jurisdictions. The assets on deposit are available to settle insurance and reinsurance liabilities. Chubb is also required to restrict assets pledged under repurchase agreements, which represent Chubb's agreement to sell securities and repurchase them at a future date for a predetermined price. We use trust funds in certain large reinsurance transactions where the trust funds are set up for the benefit of the ceding companies and generally take the place of letter of credit (LOC) requirements. We have investments in segregated portfolios primarily to provide collateral or guarantees for LOC and derivative transactions. Included in restricted assets at March 31, 2021 and December 31, 2020 are investments, primarily fixed maturities, totaling $20.8 billion and $19.6 billion, respectively, and cash of $157 million and $89 million, respectively.

The following table presents the components of restricted assets:


	March 31		December 31
(in millions of U.S. dollars)	2021		2020
Trust funds	$	13,553	$	12,305
Deposits with U.S. regulatory authorities	2,424		2,438
Deposits with non-U.S. regulatory authorities	2,917		2,905
Assets pledged under repurchase agreements	1,458		1,462
Other pledged assets	638		584
Total	$	20,990	$	19,694

Fair value measurements

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Fair value measurements

a) Fair value hierarchy

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

The three levels of the hierarchy are as follows:

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

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

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

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

would use in pricing an asset or liability.

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

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

Fixed maturities

We use pricing services to estimate fair value measurements for the majority of our fixed maturities. The pricing services use market quotations for fixed maturities that have quoted prices in active markets; such securities are classified within Level 1. For fixed maturities other than U.S. Treasury securities that generally do not trade on a daily basis, the pricing services prepare estimates of fair value measurements using their pricing applications or pricing models, which include available relevant market information, benchmark curves, benchmarking of like securities, sector groupings, and matrix pricing. Additional valuation factors that can be taken into account are nominal spreads, dollar basis, and liquidity adjustments. The pricing services evaluate each asset class based on relevant market and credit information, perceived market movements, and sector news. The market inputs used in the pricing evaluation, listed in the approximate order of priority include: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, reference data, and industry and economic events. The extent of the use of each input is dependent on the asset class and the market conditions. Given the asset class, the priority of the use of inputs may change, or some market inputs may not be relevant. Additionally, fixed maturities valuation is more subjective when markets are less liquid due to the lack of market based inputs (i.e., stale pricing) and may require the use of models to be priced. The lack of market based inputs may increase the potential that an investment's estimated fair value is not reflective of the price at which an actual transaction would occur. The overwhelming majority of fixed maturities are classified within Level 2 because the most significant inputs used in the pricing techniques are observable. For a small number of fixed maturities, we obtain a single broker quote (typically from a market maker). Due to the disclaimers on the quotes that indicate that the price is indicative only, we include these fair value estimates in Level 3.

Equity securities

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

Short-term investments

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

approaching maturity, and as such, their cost approximates fair value. Short-term investments for which pricing is unobservable are classified within Level 3.

Other investments

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

Securities lending collateral

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

Investment derivative instruments

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

Other derivative instruments

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

Separate account assets

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

Guaranteed living benefits

The GLB arises from life reinsurance programs covering living benefit guarantees whereby we assume the risk of guaranteed minimum income benefits (GMIB) associated with variable annuity contracts. GLB’s are recorded in Accounts payable, accrued expenses, and other liabilities in the Consolidated balance sheets. For GLB reinsurance, Chubb estimates fair value using an internal valuation model which includes current market information and estimates of policyholder behavior. All of the treaties contain claim limits, which are factored into the valuation model. The fair value depends on a number of factors, including interest rates, equity markets, credit risk, current account value, market volatility, expected annuitization rates and other policyholder behavior, and changes in policyholder mortality. Because of the significant use of unobservable inputs including policyholder behavior, GLB reinsurance is classified within Level 3.

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


March 31, 2021	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)
Assets:
Fixed maturities available for sale
U.S. Treasury / Agency	$	2,044	$	483	$	—	$	2,527
Non-U.S.	—		25,516		650		26,166
Corporate and asset-backed securities	—		34,788		1,612		36,400
Mortgage-backed securities	—		19,386		51		19,437
Municipal	—		6,541		—		6,541
	2,044		86,714		2,313		91,071
Equity securities	4,330		—		75		4,405
Short-term investments	2,279		1,455		1		3,735
Other investments (1)	421		446		10		877
Securities lending collateral	—		2,076		—		2,076
Investment derivative instruments	69		—		—		69
Other derivative instruments	2		—		—		2
Separate account assets	4,493		115		—		4,608
Total assets measured at fair value (1)	$	13,638	$	90,806	$	2,399	$	106,843
Liabilities:
Investment derivative instruments	$	79	$	—	$	—	$	79
Other derivative instruments	7		—		—		7
GLB (2)	—		—		760		760
Total liabilities measured at fair value	$	86	$	—	$	760	$	846

(1)Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $7,457 million, policy loans of $232 million and other investments of $70 million at March 31, 2021 measured using NAV as a practical expedient.

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


December 31, 2020	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)
Assets:
Fixed maturities available for sale
U.S. Treasury / Agency	$	2,148	$	522	$	—	$	2,670
Non-U.S.	—		25,808		546		26,354
Corporate and asset-backed securities	—		34,758		1,573		36,331
Mortgage-backed securities	—		18,410		60		18,470
Municipal	—		6,874		—		6,874
	2,148		86,372		2,179		90,699
Equity securities	3,954		—		73		4,027
Short-term investments	2,866		1,474		5		4,345
Other investments (1)	434		438		10		882
Securities lending collateral	—		1,844		—		1,844
Investment derivative instruments	35		—		—		35
Separate account assets	4,264		124		—		4,388
Total assets measured at fair value (1)	$	13,701	$	90,252	$	2,267	$	106,220
Liabilities:
Investment derivative instruments	$	52	$	—	$	—	$	52
Other derivative instruments	17		—		—		17
GLB (2)	—		—		1,089		1,089
Total liabilities measured at fair value	$	69	$	—	$	1,089	$	1,158

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

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

Level 3 financial instruments

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

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

Fair Value

Valuation
Technique

Significant
Unobservable Inputs

Ranges

Weighted Average (1)

March 31, 2021

December 31, 2020

GLB (1)

$

760

$

1,089

Actuarial model

Lapse rate

3% – 34%

4.6

%

Annuitization rate

0% – 100%

3.4

%

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

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

A lapse rate is the percentage of in-force policies surrendered in a given calendar year. All else equal, as lapse rates increase, ultimate claim payments will decrease.

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. For the three months ended March 31, 2021 and 2020, no material refinements were made to the model. For detailed information on our lapse and annuitization rate assumptions, refer to Note 4 to the Consolidated Financial Statements of our 2020 Form 10-K.

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 March 31, 2021 (in millions of U.S. dollars)	Available-for-Sale Debt Securities						Equity securities			Short-term investments			Other investments				GLB (1)
	Non-U.S.		Corporate and asset- backed securities		Mortgage-backed securities

Balance, beginning of period	$	546	$	1,573	$	60		$	73		$	5		$	10			$	1,089
Transfers into Level 3	—		17		—			—			—			—				—

Change in Net Unrealized Gains/Losses in OCI	8		6		—			—			—			—				—

Net Realized Gains/Losses	—		(3)		—			2			—			—				(319)

Purchases	121		169		—			3			1			—				—
Sales	(7)		(25)		—			(3)			—			—				—
Settlements	(18)		(125)		(9)			—			(5)			—				—
Other	—		—		—			—			—			—				(10)
Balance, end of period	$	650	$	1,612	$	51		$	75		$	1		$	10			$	760
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—	$	(3)	$	—		$	2		$	—		$	—			$	(319)
Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date	$	10	$	11	$	—		$	—		$	—		$	—			$	—

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


		Assets														Liabilities
Three Months Ended March 31, 2020 (in millions of U.S. dollars)		Available-for-Sale Debt Securities								Equity securities		Short-term investments		Other investments			GLB (1)
	Non-U.S.			Corporate and asset- backed securities			Mortgage-backed securities

Balance, beginning of period		$	449		$	1,451		$	60	$	69	$	6	$	10		$	897
Transfers into Level 3		—			91			—		—		—		—			—
Transfers out of Level 3		(3)			(1)			—		—		—		—			—
Change in Net Unrealized Gains/ Losses in OCI		(14)			(45)			—		1		—		—			—

Net Realized Gains/Losses		(2)			(13)			—		(2)		—		—			685

Purchases		82			139			—		3		1		—			—
Sales		(46)			(19)			—		(4)		—		—			—
Settlements		(1)			(101)			—		—		(6)		—			—
Other		—			—			—		—		—		—			9
Balance, end of period		$	465		$	1,502		$	60	$	67	$	1	$	10		$	1,591
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date		$	—		$	(14)		$	—	$	(2)	$	—	$	—		$	685
Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date		$	(15)		$	(44)		$	—	$	—	$	—	$	—		$	—

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

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

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

The carrying values of cash, other assets, other liabilities, and other financial instruments not included below approximated their fair values. Refer to the 2020 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:


March 31, 2021	Fair Value								Net Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities held to maturity
U.S. Treasury / Agency	$	1,144	$	53	$	—	$	1,197	$	1,158
Non-U.S.	—		1,351		—		1,351		1,270
Corporate and asset-backed securities	—		2,311		—		2,311		2,128
Mortgage-backed securities	—		1,997		—		1,997		1,887
Municipal	—		4,896		—		4,896		4,689
Total assets	$	1,144	$	10,608	$	—	$	11,752	$	11,132
Liabilities:
Repurchase agreements	$	—	$	1,405	$	—	$	1,405	$	1,405

Long-term debt	—		16,408		—		16,408		14,879
Trust preferred securities	—		470		—		470		308
Total liabilities	$	—	$	18,283	$	—	$	18,283	$	16,592


December 31, 2020	Fair Value								Net Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities held to maturity
U.S. Treasury / Agency	$	1,395	$	57	$	—	$	1,452	$	1,392
Non-U.S.	—		1,405		—		1,405		1,288
Corporate and asset-backed securities	—		2,438		—		2,438		2,150
Mortgage-backed securities	—		2,146		—		2,146		1,999
Municipal	—		5,069		—		5,069		4,824
Total assets	$	1,395	$	11,115	$	—	$	12,510	$	11,653
Liabilities:
Repurchase agreements	$	—	$	1,405	$	—	$	1,405	$	1,405

Long-term debt	—		17,487		—		17,487		14,948
Trust preferred securities	—		473		—		473		308
Total liabilities	$	—	$	19,365	$	—	$	19,365	$	16,661

Liability for Claims and Claims Adjustment Expense [Abstract]

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.

+ References + Details

Reinsurance (Notes)

3 Months Ended

Mar. 31, 2021

Reinsurance Disclosures [Abstract]

Reinsurance [Text Block]

Reinsurance

Reinsurance recoverable on ceded reinsurance


	March 31, 2021				December 31, 2020
(in millions of U.S. dollars)	Net Reinsurance Recoverable (1)		Valuation allowance		Net Reinsurance Recoverable (1)		Valuation allowance
Reinsurance recoverable on unpaid losses and loss expenses	$	14,860	$	258	$	14,647	$	257
Reinsurance recoverable on paid losses and loss expenses	1,054		59		945		57
Reinsurance recoverable on losses and loss expenses	$	15,914	$	317	$	15,592	$	314
Reinsurance recoverable on policy benefits	$	202	$	4	$	206	$	5

(1)Net of valuation allowance for uncollectible reinsurance.

The increase in reinsurance recoverable on losses and loss expenses was primarily due to unfavorable prior period development in certain lines and catastrophe losses in the quarter.

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


	Three Months Ended
	March 31
(in millions of U.S. dollars)	2021		2020
Valuation allowance for uncollectible reinsurance - beginning of period	$	314	$	316
Provision for uncollectible reinsurance	3		2
Write-offs charged against the valuation allowance	—		(13)


Valuation allowance for uncollectible reinsurance - end of period	$	317	$	305

For additional information, refer to Note 1 d) to the Consolidated Financial Statements of our 2020 Form 10-K.

Unpaid losses and loss expenses

3 Months Ended

Mar. 31, 2021

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:


	Three Months Ended
	March 31
(in millions of U.S. dollars)	2021		2020
Gross unpaid losses and loss expenses – beginning of period	$	67,811	$	62,690
Reinsurance recoverable on unpaid losses – beginning of period (1)	(14,647)		(14,181)
Net unpaid losses and loss expenses – beginning of period	53,164		48,509


Net losses and loss expenses incurred in respect of losses occurring in:
Current year	5,249		4,605
Prior years (2)	(196)		(120)
Total	5,053		4,485
Net losses and loss expenses paid in respect of losses occurring in:
Current year	732		920
Prior years	3,161		3,335
Total	3,893		4,255
Foreign currency revaluation and other	71		(565)
Net unpaid losses and loss expenses – end of period	54,395		48,174
Reinsurance recoverable on unpaid losses (1)	14,860		14,040
Gross unpaid losses and loss expenses – end of period	$	69,255	$	62,214

(1) Net of valuation allowance for uncollectible reinsurance.

(2) Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments and earned premiums totaling $4 million and $2 million for the three months ended March 31, 2021 and 2020, respectively.

Gross and net unpaid losses and loss expenses increased $1,444 million and $1,231 million, respectively, for the three months ended March 31, 2021, reflecting an increase in underlying exposure due to premium growth and catastrophe losses incurred, partially offset by favorable prior period development.

Prior Period Development

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

The following table summarizes (favorable) and adverse PPD by segment.


	Three Months Ended March 31
(in millions of U.S. dollars)		Long-tail		Short-tail		Total
2021
North America Commercial P&C Insurance		$	(46)	$	(81)	$	(127)
North America Personal P&C Insurance		—		(40)		(40)
North America Agricultural Insurance		—		(2)		(2)
Overseas General Insurance		—		(25)		(25)
Global Reinsurance		—		(7)		(7)
Corporate		9		—		9
Total		$	(37)	$	(155)	$	(192)
2020
North America Commercial P&C Insurance		$	(43)	$	(62)	$	(105)
North America Personal P&C Insurance		—		1		1
North America Agricultural Insurance		—		(14)		(14)
Overseas General Insurance		—		(4)		(4)
Global Reinsurance		—		(7)		(7)
Corporate		11		—		11
Total		$	(32)	$	(86)	$	(118)

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

North America Commercial P&C Insurance

2021

For the three months ended March 31, 2021, net favorable PPD was $127 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 $46 million in long-tail business, primarily from:

•Net favorable development of $51 million in professional liability (errors & omissions and third-party cyber risk), driven by accident years 2016 and 2017, which saw lower than expected loss emergence, partly offset by higher than expected development in accident year 2019;

•Net favorable development of $35 million in voluntary environmental lines, driven by accident years 2017 and prior, which saw lower than expected loss emergence, partly offset by higher than expected development in accident year 2019; and

•Net adverse development of $57 million in excess and umbrella portfolios, with accident years 2015 through 2019 continuing to experience higher than expected loss development, partly offset by favorable development in accident years 2014 and prior.

•Net favorable development of $81 million in short-tail business, primarily from:

•Net favorable development of $49 million in surety, mainly in accident years 2018 and 2019, driven by lower than expected loss emergence;

•Net favorable development of $48 million in accident & health, driven by accident years 2019 and 2020, where loss emergence was lower than expected;

•Net favorable development of $25 million in property and marine coverages in accident year 2020, driven by lower than expected non-catastrophe loss development; and

•Net adverse development of $41 million in first-party cyber risk, driven by accident years 2019 and 2020, which experienced higher than expected loss development as well as heightened frequency and severity.

2020

For the three months ended March 31, 2020, net favorable PPD was $105 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 $43 million in long-tail business, primarily from:

•Net favorable development of $66 million in professional liability (errors & omissions and third-party cyber risk), driven by accident years 2016 and prior, which saw lower than expected emergence;

•Net favorable development of $43 million in voluntary environmental lines, driven by accident years 2016 and prior, which saw lower than expected emergence and a favorable revision to loss development patterns;

•Net favorable development of $28 million in construction workers’ compensation, mainly in accident years 2016 and prior, which saw lower than expected reported loss emergence and a favorable revision to loss development patterns;

•Net adverse development of $49 million in excess and umbrella portfolios, with accident years 2015 through 2019 experiencing higher than expected reported development, partially offset by lower than expected emergence in accident years 2014 and prior; and

•Net adverse development of $23 million in wholesale general liability coverages, driven by higher than expected reported loss emergence in accident years 2014 through 2019.

•Net favorable development of $62 million in short-tail business, primarily from:

•Net favorable development of $36 million, in accident & health, mainly in accident years 2018 and 2019, driven by lower than expected paid loss emergence; and

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

North America Personal P&C Insurance

2021

For the three months ended March 31, 2021, net favorable PPD was $40 million, driven by accident year 2020, which experienced better than expected non-catastrophe loss development in homeowners and valuables.

Overseas General Insurance

2021

For the three months ended March 31, 2021, net favorable PPD was $25 million, which reflects favorable loss experience across several lines, mainly in accident year 2020, none of which were significant individually or in the aggregate.

Commitments, contingencies, and guarantees

3 Months Ended

Mar. 31, 2021

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 purchases to be announced mortgage-backed securities (TBAs) as part of its investing activities.

Under reinsurance programs covering GLBs, Chubb assumes the risk of GLBs, principally GMIB, associated with variable annuity contracts. The GMIB risk is triggered if, at the time the contract holder elects to convert the accumulated account value to a periodic payment stream (annuitize), the accumulated account value is not sufficient to provide a guaranteed minimum level of monthly income. The GLB reinsurance product meets the definition of a derivative instrument and is classified within AP. Chubb also generally maintains positions in exchange-traded equity futures contracts on equity market indices to limit equity exposure in the GMDB and GLB book of business.

All derivative instruments are carried at fair value with changes in fair value recorded in Net realized gains (losses) in the Consolidated statements of operations. None of the derivative instruments are designated as hedges for accounting purposes.

The following table presents the balance sheet locations, fair values of derivative instruments in an asset or (liability) position, and notional values/payment provisions of our derivative instruments:


				March 31, 2021								December 31, 2020
	Consolidated Balance Sheet Location	Fair Value				Notional Value/ Payment Provision			Fair Value					Notional Value/ Payment Provision
(in millions of U.S. dollars)		Derivative Asset		Derivative (Liability)				Derivative Asset			Derivative (Liability)
Investment and embedded derivative instruments:
Foreign currency forward contracts	OA / (AP)	$	21	$	(69)	$	3,657		$	22		$	(49)	$	2,807
Options/Futures contracts on notes, bonds, and equities	OA / (AP)	48		(10)		2,063			13			(3)		1,749
Convertible securities (1)	FM AFS / ES	11		—		13			9			—		11
		$	80	$	(79)	$	5,733		$	44		$	(52)	$	4,567
Other derivative instruments:
Futures contracts on equities (2)	OA / (AP)	$	—	$	(7)	$	761		$	—		$	(17)	$	709
Other	OA / (AP)	2		—		52			—			—		16
		$	2	$	(7)	$	813		$	—		$	(17)	$	725
GLB (3)	(AP)	$	—	$	(760)	$	1,506		$	—		$	(1,089)	$	1,658

(1)Includes fair value of embedded derivatives.

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

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

At March 31, 2021 and December 31, 2020, net derivative liabilities of $12 million and $30 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
	March 31
(in millions of U.S. dollars)	2021		2020
Investment and embedded derivative instruments:
Foreign currency forward contracts	$	(16)	$	43

All other futures contracts, options, and equities	125		(27)
Convertible securities (1)	—		(1)

Total investment and embedded derivative instruments	$	109	$	15
GLB and other derivative instruments:
GLB	$	319	$	(685)
Futures contracts on equities (2)	(44)		125
Other	(1)		(2)
Total GLB and other derivative instruments	$	274	$	(562)
	$	383	$	(547)

(1)Includes embedded derivatives.

(2)Related to GMDB and GLB book 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 currencies at a future date. Chubb uses forwards to minimize the effect of fluctuating foreign currencies as discussed above.

(ii) Duration management and market exposure

Futures

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

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

Options

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

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

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

Interest rate swaps

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

Cross-currency swaps

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

Other

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

(iii) Convertible security investments

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

(iv) TBA

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

(v) GLB

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

To mitigate adverse changes in the capital markets, we maintain positions in exchange-traded equity futures contracts, as noted under section "(ii) Futures" above. These futures increase in fair value when the S&P 500 index decreases (and decrease in fair value when the S&P 500 index increases). The net impact of gains or losses related to changes in fair value of the GLB liability and the exchange-traded equity futures are included in Net realized gains (losses).

c) Securities lending and secured borrowings

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

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


	Remaining contractual maturity

	March 31, 2021		December 31, 2020
(in millions of U.S. dollars)	Overnight and Continuous
Collateral held under securities lending agreements:
Cash	$	732	$	551
U.S. Treasury / Agency	116		148
Non-U.S.	1,068		1,032
Corporate and asset-backed securities	21		30
Mortgage-backed securities	1		4

Equity securities	138		79

	$	2,076	$	1,844
Gross amount of recognized liability for securities lending payable	$	2,076	$	1,844

At March 31, 2021 and December 31, 2020, our repurchase agreement obligations of $1,405 million 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
	March 31, 2021						December 31, 2020
	30-90 Days		Greater than 90 Days		Total		30-90 Days		Greater than 90 Days		Total
(in millions of U.S. dollars)
Collateral pledged under repurchase agreements:
Cash	$	—	$	10	$	10	$	—	$	4	$	4
U.S. Treasury / Agency	102		4		106		—		106		106


Mortgage-backed securities	—		1,342		1,342		481		871		1,352
	$	102	$	1,356	$	1,458	$	481	$	981	$	1,462
Gross amount of recognized liabilities for repurchase agreements					$	1,405					$	1,405
Difference (1)					$	53					$	57

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

Potential risks exist in our secured borrowing transactions due to market conditions and counterparty exposure. With collateral that we pledge, there is a risk that the collateral may not be returned at the expiration of the agreement. If the counterparty fails to return the collateral, Chubb will have free use of the borrowed funds until our collateral is returned. In addition, we may encounter the risk that Chubb may not be able to renew outstanding borrowings with a new term or with an existing counterparty due to market conditions including a decrease in demand as well as more restrictive terms from banks due to increased regulatory and capital constraints. Should this condition occur, Chubb may seek alternative borrowing sources or reduce borrowings. Additionally, increased margins and collateral requirements due to market conditions would increase our restricted assets as we are required to provide additional collateral to support the transaction.

d) Fixed maturities

At March 31, 2021, we have commitments to purchase fixed income securities of $591 million over the next several years.

e) Other investments

At March 31, 2021, included in Other investments in the Consolidated balance sheet are investments in limited partnerships and partially-owned investment companies with a carrying value of $7.2 billion. In connection with these investments, we have commitments that may require funding of up to $3.1 billion over the next several years. At December 31, 2020, these investments had a carrying value of $6.5 billion with a commitment that may require funding of up to $3.2 billion.

f) Income taxes

At March 31, 2021, $62 million of unrecognized tax benefits remain outstanding. It is reasonably possible that over the next twelve months, that the amount of unrecognized tax benefits may change resulting from the re-evaluation of unrecognized tax benefits arising from examinations by taxing authorities, settlements and the lapses of statutes of limitations. With few exceptions, Chubb is no longer subject to income tax examinations for years before 2012.

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.

h) Leases

At March 31, 2021 and December 31, 2020, the right-of-use asset was $448 million and $473 million, respectively, recorded within Other assets on the Consolidated balance sheets and the lease liability was $490 million and $517 million, respectively, which was recorded within Accounts payable, accrued expenses, and other liabilities on the Consolidated balance sheets. These leases consist principally of real estate operating leases that are amortized on a straight-line basis over the term of the lease, which expire at various dates.

Shareholders' equity

3 Months Ended

Mar. 31, 2021

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 the 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 March 31, 2021, our Common Shares had a par value of CHF 24.15 per share.

At our May 2020 and 2019 annual general meetings, our shareholders approved annual dividends for the following year of up to $3.12 per share and $3.00 per share, respectively, which were paid in four quarterly installments of $0.78 per share and $0.75 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.

Dividend distributions per Common Share for the three months ended March 31, 2021 and 2020 were $0.78 (CHF 0.70) and $0.75 (CHF 0.72), respectively.

Increases in Common Shares in treasury are due to open market repurchases of Common Shares and the surrender of Common Shares to satisfy tax withholding obligations in connection with the vesting of restricted stock and the forfeiture of unvested restricted stock. Decreases in Common Shares in treasury are principally due to grants of restricted stock, exercises of stock options, purchases under the Employee Stock Purchase Plan (ESPP), and share cancellations. At March 31, 2021, 27,928,305 Common Shares remain in treasury after share repurchases and 2,054,334 net shares issued under employee share-based compensation plans.

Chubb Limited securities repurchase authorizations

In November 2019, the Board authorized the repurchase of up to $1.5 billion of Chubb's Common Shares from November 21, 2019 through December 31, 2020. In November 2020, the Board authorized the repurchase of up to $1.5 billion of Chubb's Common Shares from November 19, 2020 through December 31, 2021. The $1.5 billion November 2019 Board authorization remained effective through December 31, 2020. Repurchases through December 31, 2020 were made under this authorization. In February 2021, the Board approved an increase to the November 2020 share repurchase program of $1.0 billion to a total of $2.5 billion, effective through December 31, 2021.

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				April 1, 2021 through April 29, 2021
			March 31
(in millions of U.S. dollars, except share data)	2021		2020
Number of shares repurchased	3,110,000		2,266,150			450,000
Cost of shares repurchased	$	519	$	326		$	76
Repurchase authorization remaining at end of period	$	1,982	$	1,124		$	1,906

Share-based compensation	3 Months Ended
Share-based compensation	Mar. 31, 2021
Share-based Payment Arrangement [Abstract]
Share-based compensation	Share-based compensationThe 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 respective vesting period, which is also the requisite service period. On February 25, 2021, Chubb granted 1,790,056 stock options with a weighted-average grant date fair value of $33.05 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 restricted stock awards granted comprise target awards and premium awards that cliff vest at the end of a 3-year performance period based on both 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 awards are subject to 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 25, 2021, Chubb granted 848,762 service-based restricted stock awards, 324,142 service-based restricted stock units, and 284,766 performance-based stock awards to employees and officers with a grant date fair value of $164.94 each. Each restricted stock unit represents our obligation to deliver to the holder one Common Share upon vesting.

Postretirement benefits

3 Months Ended

Mar. 31, 2021

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 Benefit Plans								Other Postretirement Benefit Plans
	2021				2020				2021		2020
Three Months Ended March 31	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
Service cost	$	—	$	1	$	—	$	1	$	—	$	—
Non-service cost (benefit):
Interest cost	18		5		25		6		—		1
Expected return on plan assets	(64)		(11)		(56)		(10)		—		(1)
Amortization of net actuarial loss	—		1		—		—		—		—
Amortization of prior service cost	—		—		—		—		(20)		(20)

Settlements	—		—		1		—		—		—
Total non-service cost (benefit)	(46)		(5)		(30)		(4)		(20)		(20)
Net periodic benefit cost (benefit)	$	(46)	$	(4)	$	(30)	$	(3)	$	(20)	$	(20)

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


	Pension Benefit Plans				Other Postretirement Benefit Plans
Three Months Ended March 31	2021		2020		2021		2020
(in millions of U.S. dollars)
Service cost:
Losses and loss expenses	$	—	$	—	$	—	$	—
Administrative expenses	1		1		—		—
Total service cost	1		1		—		—
Non-service cost (benefit):
Losses and loss expenses	(5)		(3)		(2)		(2)
Administrative expenses	(46)		(31)		(18)		(18)
Total non-service cost (benefit)	(51)		(34)		(20)		(20)
Net periodic benefit cost (benefit)	$	(50)	$	(33)	$	(20)	$	(20)

Segment information

3 Months Ended

Mar. 31, 2021

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 losses and loss expenses of asbestos and environmental (A&E) liabilities and certain other non-A&E run-off exposures.

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

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

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

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

The following tables present the Statement of Operations by segment:


For the Three Months Ended March 31, 2021 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated



Net premiums written	$	3,664	$	1,098	$	183	$	2,890	$	207	$	620	$	—	$	—	$	8,662
Net premiums earned	3,674		1,184		110		2,478		180		595		—		—		8,221
Losses and loss expenses	2,560		819		85		1,263		120		198		9		(1)		5,053
Policy benefits	—		—		—		—		—		163		—		4		167
Policy acquisition costs	514		247		12		668		45		179		—		—		1,665
Administrative expenses	254		60		3		266		8		82		71		—		744
Underwriting income (loss)	346		58		10		281		7		(27)		(80)		(3)		592
Net investment income (loss)	540		65		7		141		70		98		(17)		(41)		863
Other (income) expense	2		1		—		1		—		(34)		(415)		(45)		(490)
Amortization expense of purchased intangibles	—		3		7		12		—		1		49		—		72
Segment income	$	884	$	119	$	10	$	409	$	77	$	104	$	269	$	1	$	1,873
Net realized gains (losses)													888		(1)		887
Interest expense													122		—		122

Income tax expense													338		—		338
Net income													$	697	$	—	$	2,300


For the Three Months Ended March 31, 2020 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated



Net premiums written	$	3,252	$	1,107	$	157	$	2,598	$	218	$	645	$	—	$	—	$	7,977
Net premiums earned	3,376		1,200		94		2,307		186		631		—		—		7,794
Losses and loss expenses	2,181		683		65		1,258		87		202		11		(2)		4,485
Policy benefits	—		—		—		—		—		185		—		(56)		129
Policy acquisition costs	492		245		11		642		45		180		—		—		1,615
Administrative expenses	259		68		4		258		10		76		66		—		741
Underwriting income (loss)	444		204		14		149		44		(12)		(77)		58		824
Net investment income (loss)	525		66		9		145		69		95		(24)		(24)		861
Other (income) expense	6		2		—		4		—		(12)		23		32		55
Amortization expense of purchased intangibles	—		3		7		12		—		1		50		—		73
Segment income (loss)	$	963	$	265	$	16	$	278	$	113	$	94	$	(174)	$	2	$	1,557
Net realized gains (losses)													(956)		(2)		(958)
Interest expense													132		—		132

Income tax expense													215		—		215
Net income (loss)													$	(1,477)	$	—	$	252

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

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

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Disclosure Text Block Supplement [Abstract]

Earnings per share

3 Months Ended

Mar. 31, 2021

Earnings Per Share [Abstract]

Earnings per share


	Three Months Ended
	March 31
(in millions of U.S. dollars, except share and per share data)	2021		2020
Numerator:
Net income	$	2,300	$	252
Denominator:
Denominator for basic earnings per share:
Weighted-average shares outstanding	450,539,568		451,868,658
Denominator for diluted earnings per share:
Share-based compensation plans	2,795,971		2,651,610
Weighted-average shares outstanding and assumed conversions	453,335,539		454,520,268
Basic earnings per share	$	5.10	$	0.56
Diluted earnings per share	$	5.07	$	0.55
Potential anti-dilutive share conversions	1,952,612		3,154,406

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

3 Months Ended

Mar. 31, 2021

Information provided in connection with outstanding debt of subsidiaries

Chubb INA Holdings Inc. (Subsidiary Issuer) is an indirect 100 percent-owned and consolidated subsidiary of Chubb Limited (Parent Guarantor). The Parent Guarantor fully and unconditionally guarantees certain of the debt of the Subsidiary Issuer. Certain information included relates to our compliance with our debt covenants.

The following table presents the condensed balance sheets of Chubb Limited and Chubb INA Holdings Inc.:


	Chubb Limited (Parent Guarantor) (1)				Chubb INA Holdings Inc. (Subsidiary Issuer)
(in millions of U.S. dollars)	March 31, 2021		December 31, 2020		March 31, 2021		December 31, 2020
Assets
Investments	$	—	$	—	$	206	$	197
Cash	23		84		1		1

Due from subsidiaries and affiliates, net	3,510		3,522		—		—
Other assets	8		10		415		463
Total assets	$	3,541	$	3,616	$	622	$	661
Liabilities
Due to subsidiaries and affiliates, net	$	—	$	—	$	3,079	$	3,008
Affiliated notional cash pooling programs	—		—		361		272

Long-term debt	—		—		14,879		14,948
Trust preferred securities	—		—		308		308
Other liabilities	337		323		1,281		1,418
Total liabilities	337		323		19,908		19,954
Total shareholders’ equity (2)	3,204		3,293		(19,286)		(19,293)
Total liabilities and shareholders’ equity	$	3,541	$	3,616	$	622	$	661

(1)Excludes investment in subsidiary issuer (presented separately).

(2)Total shareholders' equity of Parent Guarantor excludes $55.9 billion and $56.1 billion of investment in subsidiaries, including Subsidiary Issuer, at March 31, 2021 and December 31, 2020, respectively. Total shareholders' equity of Subsidiary Issuer excludes $54.5 billion and $55.2 billion of investment in subsidiaries at March 31, 2021 and December 31, 2020, respectively.

The following table presents the condensed statements of operations and comprehensive income of Chubb Limited and Chubb INA Holdings Inc.:


	Chubb Limited (Parent Guarantor) (1)				Chubb INA Holdings Inc. (Subsidiary Issuer)
Three Months Ended March 31	2021		2020		2021		2020
(in millions of U.S. dollars)
Net investment income (loss)	$	1	$	(2)	$	1	$	4

Net realized gains (loss)	13		(21)		67		113
Administrative expenses	22		24		(52)		(38)
Interest (income) expense	(34)		(34)		145		148
Other (income) expense	(13)		(9)		(5)		8
Income tax expense (benefit)	11		—		(22)		7
Net income (loss) (2)	$	28	$	(4)	$	2	$	(8)
Comprehensive income (loss)	$	28	$	(4)	$	1	$	(38)

(1)Excludes investment in subsidiary issuer (presented separately).

(2)Net income of Parent Guarantor excludes equity in earnings from investment in subsidiaries, including Subsidiary Issuer, of $2,272 million and $256 million for the three months ended March 31, 2021 and 2020, respectively. Net income of Subsidiary Issuer excludes equity in earnings from investment in subsidiaries of $1,031 million and $593 million for the three months ended March 31, 2021 and 2020, respectively

General (Policies)

3 Months Ended

Mar. 31, 2021

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of presentation

Chubb Limited is a holding company incorporated in Zurich, Switzerland. Chubb Limited, through its subsidiaries, provides a broad range of insurance and reinsurance products to insureds worldwide. Our results are reported through the following business segments: North America Commercial P&C Insurance, North America Personal P&C Insurance, North America Agricultural Insurance, Overseas General Insurance, Global Reinsurance, and Life Insurance. Refer to Note 11 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 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 2020 Form 10-K.

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

Restricted cash

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

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


	March 31		December 31
(in millions of U.S. dollars)	2021		2020
Cash	$	1,684	$	1,747
Restricted cash	157		89
Total cash and restricted cash shown in the Consolidated statements of cash flows	$	1,841	$	1,836

Accounting guidance not yet adopted

Targeted Improvements to the Accounting for Long-Duration Contracts

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

Fair value measurements Fair Value Measurement Policy (Policies)	3 Months Ended
	Mar. 31, 2021
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)

3 Months Ended

Mar. 31, 2021

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:


	March 31		December 31
(in millions of U.S. dollars)	2021		2020
Cash	$	1,684	$	1,747
Restricted cash	157		89
Total cash and restricted cash shown in the Consolidated statements of cash flows	$	1,841	$	1,836

Investments (Tables)

3 Months Ended

Mar. 31, 2021

Investments, Debt and Equity Securities [Abstract]

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


March 31, 2021	Amortized Cost		Valuation Allowance		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	2,413	$	—	$	121	$	(7)	$	2,527
Non-U.S.	25,147		(6)		1,214		(189)		26,166
Corporate and asset-backed securities	35,224		(9)		1,474		(289)		36,400
Mortgage-backed securities	18,788		—		738		(89)		19,437
Municipal	6,301		—		254		(14)		6,541
	$	87,873	$	(15)	$	3,801	$	(588)	$	91,071
	Amortized Cost		Valuation Allowance		Net Carrying Value		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value

Held to maturity
U.S. Treasury / Agency	$	1,158	$	—	$	1,158	$	39	$	—	$	1,197
Non-U.S.	1,276		(6)		1,270		82		(1)		1,351
Corporate and asset-backed securities	2,163		(35)		2,128		183		—		2,311
Mortgage-backed securities	1,888		(1)		1,887		110		—		1,997
Municipal	4,690		(1)		4,689		207		—		4,896
	$	11,175	$	(43)	$	11,132	$	621	$	(1)	$	11,752


December 31, 2020	Amortized Cost		Valuation Allowance		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	2,471	$	—	$	199	$	—	$	2,670
Non-U.S.	24,594		(6)		1,808		(42)		26,354
Corporate and asset-backed securities	34,095		(14)		2,322		(72)		36,331
Mortgage-backed securities	17,456		—		1,022		(8)		18,470
Municipal	6,572		—		304		(2)		6,874
	$	85,188	$	(20)	$	5,655	$	(124)	$	90,699
	Amortized Cost		Valuation Allowance		Net Carrying Value		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value

Held to maturity
U.S. Treasury / Agency	$	1,392	$	—	$	1,392	$	60	$	—	$	1,452
Non-U.S.	1,295		(7)		1,288		118		(1)		1,405
Corporate and asset-backed securities	2,185		(35)		2,150		288		—		2,438
Mortgage-backed securities	2,000		(1)		1,999		148		(1)		2,146
Municipal	4,825		(1)		4,824		245		—		5,069
	$	11,697	$	(44)	$	11,653	$	859	$	(2)	$	12,510

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


March 31, 2021	Amortized Cost		Valuation Allowance		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	2,413	$	—	$	121	$	(7)	$	2,527
Non-U.S.	25,147		(6)		1,214		(189)		26,166
Corporate and asset-backed securities	35,224		(9)		1,474		(289)		36,400
Mortgage-backed securities	18,788		—		738		(89)		19,437
Municipal	6,301		—		254		(14)		6,541
	$	87,873	$	(15)	$	3,801	$	(588)	$	91,071
	Amortized Cost		Valuation Allowance		Net Carrying Value		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value

Held to maturity
U.S. Treasury / Agency	$	1,158	$	—	$	1,158	$	39	$	—	$	1,197
Non-U.S.	1,276		(6)		1,270		82		(1)		1,351
Corporate and asset-backed securities	2,163		(35)		2,128		183		—		2,311
Mortgage-backed securities	1,888		(1)		1,887		110		—		1,997
Municipal	4,690		(1)		4,689		207		—		4,896
	$	11,175	$	(43)	$	11,132	$	621	$	(1)	$	11,752


December 31, 2020	Amortized Cost		Valuation Allowance		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value
(in millions of U.S. dollars)
Available for sale
U.S. Treasury / Agency	$	2,471	$	—	$	199	$	—	$	2,670
Non-U.S.	24,594		(6)		1,808		(42)		26,354
Corporate and asset-backed securities	34,095		(14)		2,322		(72)		36,331
Mortgage-backed securities	17,456		—		1,022		(8)		18,470
Municipal	6,572		—		304		(2)		6,874
	$	85,188	$	(20)	$	5,655	$	(124)	$	90,699
	Amortized Cost		Valuation Allowance		Net Carrying Value		Gross Unrealized Appreciation		Gross Unrealized Depreciation		Fair Value

Held to maturity
U.S. Treasury / Agency	$	1,392	$	—	$	1,392	$	60	$	—	$	1,452
Non-U.S.	1,295		(7)		1,288		118		(1)		1,405
Corporate and asset-backed securities	2,185		(35)		2,150		288		—		2,438
Mortgage-backed securities	2,000		(1)		1,999		148		(1)		2,146
Municipal	4,825		(1)		4,824		245		—		5,069
	$	11,697	$	(44)	$	11,653	$	859	$	(2)	$	12,510

Debt Securities, Held-to-maturity, Credit Quality Indicator [Table Text Block]

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


	March 31, 2021				December 31, 2020
(in millions of U.S. dollars, except for percentages)	Amortized cost		% of Total		Amortized cost		% of Total
AAA	$	2,404	22	%	$	2,511	22	%
AA	5,815		52	%	6,193		53	%
A	2,109		19	%	2,138		18	%
BBB	818		7	%	826		7	%
BB	28		—	%	28		—	%
Other	1		—	%	1		—	%
Total	$	11,175	100	%	$	11,697	100	%

Schedule Of Fixed Maturities By Contractual Maturity

The following table presents fixed maturities by contractual maturity:


			March 31				December 31
			2021				2020
(in millions of U.S. dollars)	Net Carrying Value		Fair Value		Net Carrying Value		Fair Value
Available for sale
Due in 1 year or less	$	4,767	$	4,767	$	4,760	$	4,760
Due after 1 year through 5 years	26,100		26,100		26,227		26,227
Due after 5 years through 10 years	27,394		27,394		27,232		27,232
Due after 10 years	13,373		13,373		14,010		14,010
	71,634		71,634		72,229		72,229
Mortgage-backed securities	19,437		19,437		18,470		18,470
	$	91,071	$	91,071	$	90,699	$	90,699
Held to maturity
Due in 1 year or less	$	1,099	$	1,109	$	1,231	$	1,240
Due after 1 year through 5 years	3,471		3,613		3,592		3,760
Due after 5 years through 10 years	2,918		3,072		3,029		3,228
Due after 10 years	1,757		1,961		1,802		2,136
	9,245		9,755		9,654		10,364
Mortgage-backed securities	1,887		1,997		1,999		2,146
	$	11,132	$	11,752	$	11,653	$	12,510

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


	0 – 12 Months				Over 12 Months				Total
March 31, 2021	Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss		Fair Value		Gross Unrealized Loss
(in millions of U.S. dollars)
U.S. Treasury / Agency	$	220	$	(7)	$	—	$	—	$	220	$	(7)
Non-U.S.	4,775		(161)		381		(19)		5,156		(180)
Corporate and asset-backed securities	6,753		(254)		737		(19)		7,490		(273)
Mortgage-backed securities	5,470		(87)		62		(2)		5,532		(89)
Municipal	367		(13)		14		(1)		381		(14)
Total AFS fixed maturities	$	17,585	$	(522)	$	1,194	$	(41)	$	18,779	$	(563)


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

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

Schedule of Realized Gain (Loss)

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


	Three Months Ended
	March 31
(in millions of U.S. dollars)	2021		2020
Fixed maturities:



Gross realized gains	$	37	$	77
Gross realized losses	(19)		(125)
Net (provision for) recovery of expected credit losses	6		(150)
Impairment (1)	—		(121)
Total fixed maturities	$	24	$	(319)
Equity securities	367		(29)

Other investments	38		5
Foreign exchange gains (losses)	76		(68)
Investment and embedded derivative instruments	109		15
Fair value adjustments on insurance derivative	319		(685)
S&P futures	(44)		125
Other derivative instruments	(1)		(2)
Other	(1)		—
Net realized gains (losses) (pre-tax)	$	887	$	(958)

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

Gain (Loss) on Securities [Table Text Block]

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


							Three Months Ended
							March 31
	2021						2020
(in millions of U.S. dollars)	Equity Securities		Other Investments		Total		Equity Securities		Other Investments		Total
Net gains (losses) recognized during the period	$	367	$	38	$	405	$	(29)	$	5	$	(24)
Less: Net gains (losses) recognized from sales of securities	45		—		45		(24)		—		(24)
Unrealized gains (losses) recognized for securities still held at reporting date	$	322	$	38	$	360	$	(5)	$	5	$	—

Schedule Of Components Of Restricted Assets

The following table presents the components of restricted assets:


	March 31		December 31
(in millions of U.S. dollars)	2021		2020
Trust funds	$	13,553	$	12,305
Deposits with U.S. regulatory authorities	2,424		2,438
Deposits with non-U.S. regulatory authorities	2,917		2,905
Assets pledged under repurchase agreements	1,458		1,462
Other pledged assets	638		584
Total	$	20,990	$	19,694

Debt Securities, Available-for-sale, Allowance for Credit Loss [Table Text Block]

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


	Three Months Ended
			March 31
(in millions of U.S. dollars)	2021		2020
Available for sale
Valuation allowance for expected credit losses - beginning of period	$	20	$	—
Impact of adoption of new accounting guidance	—		25
Provision for expected credit loss	4		149
Initial allowance for purchased securities with credit deterioration	—		2


Recovery of expected credit loss	(9)		—
Valuation allowance for expected credit losses - end of period	$	15	$	176
Held to maturity
Valuation allowance for expected credit losses - beginning of period	$	44	$	—
Impact of adoption of new accounting guidance	—		44
Provision for expected credit loss	—		1


Recovery of expected credit loss	(1)		—
Valuation allowance for expected credit losses - end of period	$	43	$	45

Debt Securities, Held-to-maturity, Allowance for Credit Loss [Table Text Block]

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


	Three Months Ended
			March 31
(in millions of U.S. dollars)	2021		2020
Available for sale
Valuation allowance for expected credit losses - beginning of period	$	20	$	—
Impact of adoption of new accounting guidance	—		25
Provision for expected credit loss	4		149
Initial allowance for purchased securities with credit deterioration	—		2


Recovery of expected credit loss	(9)		—
Valuation allowance for expected credit losses - end of period	$	15	$	176
Held to maturity
Valuation allowance for expected credit losses - beginning of period	$	44	$	—
Impact of adoption of new accounting guidance	—		44
Provision for expected credit loss	—		1


Recovery of expected credit loss	(1)		—
Valuation allowance for expected credit losses - end of period	$	43	$	45

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


				March 31				December 31
	Expected Liquidation Period of Underlying Assets			2021				2020
(in millions of U.S. dollars)		Fair Value		Maximum Future Funding Commitments		Fair Value		Maximum Future Funding Commitments
Financial	2 to 10 Years	$	710	$	270	$	673	$	237
Real Assets	2 to 11 Years	942		621		805		598
Distressed	2 to 8 Years	481		864		358		970
Private Credit	3 to 8 Years	86		276		88		270
Traditional	2 to 14 Years	4,912		1,039		4,519		1,125
Vintage	1 to 2 Years	72		—		73		—
Investment funds	Not Applicable	254		—		254		—
		$	7,457	$	3,070	$	6,770	$	3,200

Fair value measurements (Tables)

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Financial Instruments Measured At Fair Value On A Recurring Basis

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


March 31, 2021	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)
Assets:
Fixed maturities available for sale
U.S. Treasury / Agency	$	2,044	$	483	$	—	$	2,527
Non-U.S.	—		25,516		650		26,166
Corporate and asset-backed securities	—		34,788		1,612		36,400
Mortgage-backed securities	—		19,386		51		19,437
Municipal	—		6,541		—		6,541
	2,044		86,714		2,313		91,071
Equity securities	4,330		—		75		4,405
Short-term investments	2,279		1,455		1		3,735
Other investments (1)	421		446		10		877
Securities lending collateral	—		2,076		—		2,076
Investment derivative instruments	69		—		—		69
Other derivative instruments	2		—		—		2
Separate account assets	4,493		115		—		4,608
Total assets measured at fair value (1)	$	13,638	$	90,806	$	2,399	$	106,843
Liabilities:
Investment derivative instruments	$	79	$	—	$	—	$	79
Other derivative instruments	7		—		—		7
GLB (2)	—		—		760		760
Total liabilities measured at fair value	$	86	$	—	$	760	$	846

(1)Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $7,457 million, policy loans of $232 million and other investments of $70 million at March 31, 2021 measured using NAV as a practical expedient.

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


December 31, 2020	Level 1		Level 2		Level 3		Total
(in millions of U.S. dollars)
Assets:
Fixed maturities available for sale
U.S. Treasury / Agency	$	2,148	$	522	$	—	$	2,670
Non-U.S.	—		25,808		546		26,354
Corporate and asset-backed securities	—		34,758		1,573		36,331
Mortgage-backed securities	—		18,410		60		18,470
Municipal	—		6,874		—		6,874
	2,148		86,372		2,179		90,699
Equity securities	3,954		—		73		4,027
Short-term investments	2,866		1,474		5		4,345
Other investments (1)	434		438		10		882
Securities lending collateral	—		1,844		—		1,844
Investment derivative instruments	35		—		—		35
Separate account assets	4,264		124		—		4,388
Total assets measured at fair value (1)	$	13,701	$	90,252	$	2,267	$	106,220
Liabilities:
Investment derivative instruments	$	52	$	—	$	—	$	52
Other derivative instruments	17		—		—		17
GLB (2)	—		—		1,089		1,089
Total liabilities measured at fair value	$	69	$	—	$	1,089	$	1,158

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

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

Schedule Of Significant Unobservable Inputs Used In Level 3 Liability Valuations

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

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

Fair Value

Valuation
Technique

Significant
Unobservable Inputs

Ranges

Weighted Average (1)

March 31, 2021

December 31, 2020

GLB (1)

$

760

$

1,089

Actuarial model

Lapse rate

3% – 34%

4.6

%

Annuitization rate

0% – 100%

3.4

%

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 March 31, 2021 (in millions of U.S. dollars)	Available-for-Sale Debt Securities						Equity securities			Short-term investments			Other investments				GLB (1)
	Non-U.S.		Corporate and asset- backed securities		Mortgage-backed securities

Balance, beginning of period	$	546	$	1,573	$	60		$	73		$	5		$	10			$	1,089
Transfers into Level 3	—		17		—			—			—			—				—

Change in Net Unrealized Gains/Losses in OCI	8		6		—			—			—			—				—

Net Realized Gains/Losses	—		(3)		—			2			—			—				(319)

Purchases	121		169		—			3			1			—				—
Sales	(7)		(25)		—			(3)			—			—				—
Settlements	(18)		(125)		(9)			—			(5)			—				—
Other	—		—		—			—			—			—				(10)
Balance, end of period	$	650	$	1,612	$	51		$	75		$	1		$	10			$	760
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—	$	(3)	$	—		$	2		$	—		$	—			$	(319)
Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date	$	10	$	11	$	—		$	—		$	—		$	—			$	—

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


		Assets														Liabilities
Three Months Ended March 31, 2020 (in millions of U.S. dollars)		Available-for-Sale Debt Securities								Equity securities		Short-term investments		Other investments			GLB (1)
	Non-U.S.			Corporate and asset- backed securities			Mortgage-backed securities

Balance, beginning of period		$	449		$	1,451		$	60	$	69	$	6	$	10		$	897
Transfers into Level 3		—			91			—		—		—		—			—
Transfers out of Level 3		(3)			(1)			—		—		—		—			—
Change in Net Unrealized Gains/ Losses in OCI		(14)			(45)			—		1		—		—			—

Net Realized Gains/Losses		(2)			(13)			—		(2)		—		—			685

Purchases		82			139			—		3		1		—			—
Sales		(46)			(19)			—		(4)		—		—			—
Settlements		(1)			(101)			—		—		(6)		—			—
Other		—			—			—		—		—		—			9
Balance, end of period		$	465		$	1,502		$	60	$	67	$	1	$	10		$	1,591
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date		$	—		$	(14)		$	—	$	(2)	$	—	$	—		$	685
Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date		$	(15)		$	(44)		$	—	$	—	$	—	$	—		$	—

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

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

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 March 31, 2021 (in millions of U.S. dollars)	Available-for-Sale Debt Securities						Equity securities			Short-term investments			Other investments				GLB (1)
	Non-U.S.		Corporate and asset- backed securities		Mortgage-backed securities

Balance, beginning of period	$	546	$	1,573	$	60		$	73		$	5		$	10			$	1,089
Transfers into Level 3	—		17		—			—			—			—				—

Change in Net Unrealized Gains/Losses in OCI	8		6		—			—			—			—				—

Net Realized Gains/Losses	—		(3)		—			2			—			—				(319)

Purchases	121		169		—			3			1			—				—
Sales	(7)		(25)		—			(3)			—			—				—
Settlements	(18)		(125)		(9)			—			(5)			—				—
Other	—		—		—			—			—			—				(10)
Balance, end of period	$	650	$	1,612	$	51		$	75		$	1		$	10			$	760
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—	$	(3)	$	—		$	2		$	—		$	—			$	(319)
Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date	$	10	$	11	$	—		$	—		$	—		$	—			$	—

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


		Assets														Liabilities
Three Months Ended March 31, 2020 (in millions of U.S. dollars)		Available-for-Sale Debt Securities								Equity securities		Short-term investments		Other investments			GLB (1)
	Non-U.S.			Corporate and asset- backed securities			Mortgage-backed securities

Balance, beginning of period		$	449		$	1,451		$	60	$	69	$	6	$	10		$	897
Transfers into Level 3		—			91			—		—		—		—			—
Transfers out of Level 3		(3)			(1)			—		—		—		—			—
Change in Net Unrealized Gains/ Losses in OCI		(14)			(45)			—		1		—		—			—

Net Realized Gains/Losses		(2)			(13)			—		(2)		—		—			685

Purchases		82			139			—		3		1		—			—
Sales		(46)			(19)			—		(4)		—		—			—
Settlements		(1)			(101)			—		—		(6)		—			—
Other		—			—			—		—		—		—			9
Balance, end of period		$	465		$	1,502		$	60	$	67	$	1	$	10		$	1,591
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date		$	—		$	(14)		$	—	$	(2)	$	—	$	—		$	685
Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date		$	(15)		$	(44)		$	—	$	—	$	—	$	—		$	—

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

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

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


March 31, 2021	Fair Value								Net Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities held to maturity
U.S. Treasury / Agency	$	1,144	$	53	$	—	$	1,197	$	1,158
Non-U.S.	—		1,351		—		1,351		1,270
Corporate and asset-backed securities	—		2,311		—		2,311		2,128
Mortgage-backed securities	—		1,997		—		1,997		1,887
Municipal	—		4,896		—		4,896		4,689
Total assets	$	1,144	$	10,608	$	—	$	11,752	$	11,132
Liabilities:
Repurchase agreements	$	—	$	1,405	$	—	$	1,405	$	1,405

Long-term debt	—		16,408		—		16,408		14,879
Trust preferred securities	—		470		—		470		308
Total liabilities	$	—	$	18,283	$	—	$	18,283	$	16,592


December 31, 2020	Fair Value								Net Carrying Value
(in millions of U.S. dollars)	Level 1		Level 2		Level 3		Total
Assets:
Fixed maturities held to maturity
U.S. Treasury / Agency	$	1,395	$	57	$	—	$	1,452	$	1,392
Non-U.S.	—		1,405		—		1,405		1,288
Corporate and asset-backed securities	—		2,438		—		2,438		2,150
Mortgage-backed securities	—		2,146		—		2,146		1,999
Municipal	—		5,069		—		5,069		4,824
Total assets	$	1,395	$	11,115	$	—	$	12,510	$	11,653
Liabilities:
Repurchase agreements	$	—	$	1,405	$	—	$	1,405	$	1,405

Long-term debt	—		17,487		—		17,487		14,948
Trust preferred securities	—		473		—		473		308
Total liabilities	$	—	$	19,365	$	—	$	19,365	$	16,661

Reinsurance (Tables)

3 Months Ended

Mar. 31, 2021

Reinsurance Disclosures [Abstract]

schedule of reinsurance recoverable on ceded insurance


	March 31, 2021				December 31, 2020
(in millions of U.S. dollars)	Net Reinsurance Recoverable (1)		Valuation allowance		Net Reinsurance Recoverable (1)		Valuation allowance
Reinsurance recoverable on unpaid losses and loss expenses	$	14,860	$	258	$	14,647	$	257
Reinsurance recoverable on paid losses and loss expenses	1,054		59		945		57
Reinsurance recoverable on losses and loss expenses	$	15,914	$	317	$	15,592	$	314
Reinsurance recoverable on policy benefits	$	202	$	4	$	206	$	5

(1)Net of valuation allowance for uncollectible reinsurance.

Reinsurance Recoverable, Allowance for Credit Loss [Table Text Block]

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


	Three Months Ended
	March 31
(in millions of U.S. dollars)	2021		2020
Valuation allowance for uncollectible reinsurance - beginning of period	$	314	$	316
Provision for uncollectible reinsurance	3		2
Write-offs charged against the valuation allowance	—		(13)


Valuation allowance for uncollectible reinsurance - end of period	$	317	$	305

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

3 Months Ended

Mar. 31, 2021

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:


	Three Months Ended
	March 31
(in millions of U.S. dollars)	2021		2020
Gross unpaid losses and loss expenses – beginning of period	$	67,811	$	62,690
Reinsurance recoverable on unpaid losses – beginning of period (1)	(14,647)		(14,181)
Net unpaid losses and loss expenses – beginning of period	53,164		48,509


Net losses and loss expenses incurred in respect of losses occurring in:
Current year	5,249		4,605
Prior years (2)	(196)		(120)
Total	5,053		4,485
Net losses and loss expenses paid in respect of losses occurring in:
Current year	732		920
Prior years	3,161		3,335
Total	3,893		4,255
Foreign currency revaluation and other	71		(565)
Net unpaid losses and loss expenses – end of period	54,395		48,174
Reinsurance recoverable on unpaid losses (1)	14,860		14,040
Gross unpaid losses and loss expenses – end of period	$	69,255	$	62,214

(1) Net of valuation allowance for uncollectible reinsurance.

(2) Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments and earned premiums totaling $4 million and $2 million for the three months ended March 31, 2021 and 2020, respectively.

Prior Period Development, by Segment [Table Text Block]

The following table summarizes (favorable) and adverse PPD by segment.


	Three Months Ended March 31
(in millions of U.S. dollars)		Long-tail		Short-tail		Total
2021
North America Commercial P&C Insurance		$	(46)	$	(81)	$	(127)
North America Personal P&C Insurance		—		(40)		(40)
North America Agricultural Insurance		—		(2)		(2)
Overseas General Insurance		—		(25)		(25)
Global Reinsurance		—		(7)		(7)
Corporate		9		—		9
Total		$	(37)	$	(155)	$	(192)
2020
North America Commercial P&C Insurance		$	(43)	$	(62)	$	(105)
North America Personal P&C Insurance		—		1		1
North America Agricultural Insurance		—		(14)		(14)
Overseas General Insurance		—		(4)		(4)
Global Reinsurance		—		(7)		(7)
Corporate		11		—		11
Total		$	(32)	$	(86)	$	(118)

Commitments, contingencies, and guarantees (Tables)

3 Months Ended

Mar. 31, 2021

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:


				March 31, 2021								December 31, 2020
	Consolidated Balance Sheet Location	Fair Value				Notional Value/ Payment Provision			Fair Value					Notional Value/ Payment Provision
(in millions of U.S. dollars)		Derivative Asset		Derivative (Liability)				Derivative Asset			Derivative (Liability)
Investment and embedded derivative instruments:
Foreign currency forward contracts	OA / (AP)	$	21	$	(69)	$	3,657		$	22		$	(49)	$	2,807
Options/Futures contracts on notes, bonds, and equities	OA / (AP)	48		(10)		2,063			13			(3)		1,749
Convertible securities (1)	FM AFS / ES	11		—		13			9			—		11
		$	80	$	(79)	$	5,733		$	44		$	(52)	$	4,567
Other derivative instruments:
Futures contracts on equities (2)	OA / (AP)	$	—	$	(7)	$	761		$	—		$	(17)	$	709
Other	OA / (AP)	2		—		52			—			—		16
		$	2	$	(7)	$	813		$	—		$	(17)	$	725
GLB (3)	(AP)	$	—	$	(760)	$	1,506		$	—		$	(1,089)	$	1,658

(1)Includes fair value of embedded derivatives.

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

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

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
	March 31
(in millions of U.S. dollars)	2021		2020
Investment and embedded derivative instruments:
Foreign currency forward contracts	$	(16)	$	43

All other futures contracts, options, and equities	125		(27)
Convertible securities (1)	—		(1)

Total investment and embedded derivative instruments	$	109	$	15
GLB and other derivative instruments:
GLB	$	319	$	(685)
Futures contracts on equities (2)	(44)		125
Other	(1)		(2)
Total GLB and other derivative instruments	$	274	$	(562)
	$	383	$	(547)

(1)Includes embedded derivatives.

(2)Related to GMDB and GLB book 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

	March 31, 2021		December 31, 2020
(in millions of U.S. dollars)	Overnight and Continuous
Collateral held under securities lending agreements:
Cash	$	732	$	551
U.S. Treasury / Agency	116		148
Non-U.S.	1,068		1,032
Corporate and asset-backed securities	21		30
Mortgage-backed securities	1		4

Equity securities	138		79

	$	2,076	$	1,844
Gross amount of recognized liability for securities lending payable	$	2,076	$	1,844

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
	March 31, 2021						December 31, 2020
	30-90 Days		Greater than 90 Days		Total		30-90 Days		Greater than 90 Days		Total
(in millions of U.S. dollars)
Collateral pledged under repurchase agreements:
Cash	$	—	$	10	$	10	$	—	$	4	$	4
U.S. Treasury / Agency	102		4		106		—		106		106


Mortgage-backed securities	—		1,342		1,342		481		871		1,352
	$	102	$	1,356	$	1,458	$	481	$	981	$	1,462
Gross amount of recognized liabilities for repurchase agreements					$	1,405					$	1,405
Difference (1)					$	53					$	57

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

Shareholders' Equity (Tables)

3 Months Ended

Mar. 31, 2021

Stockholders' Equity Note [Abstract]

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				April 1, 2021 through April 29, 2021
			March 31
(in millions of U.S. dollars, except share data)	2021		2020
Number of shares repurchased	3,110,000		2,266,150			450,000
Cost of shares repurchased	$	519	$	326		$	76
Repurchase authorization remaining at end of period	$	1,982	$	1,124		$	1,906

Postretirement benefits (Tables)

3 Months Ended

Mar. 31, 2021

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

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 Benefit Plans								Other Postretirement Benefit Plans
	2021				2020				2021		2020
Three Months Ended March 31	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
(in millions of U.S. dollars)
Service cost	$	—	$	1	$	—	$	1	$	—	$	—
Non-service cost (benefit):
Interest cost	18		5		25		6		—		1
Expected return on plan assets	(64)		(11)		(56)		(10)		—		(1)
Amortization of net actuarial loss	—		1		—		—		—		—
Amortization of prior service cost	—		—		—		—		(20)		(20)

Settlements	—		—		1		—		—		—
Total non-service cost (benefit)	(46)		(5)		(30)		(4)		(20)		(20)
Net periodic benefit cost (benefit)	$	(46)	$	(4)	$	(30)	$	(3)	$	(20)	$	(20)

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


	Pension Benefit Plans				Other Postretirement Benefit Plans
Three Months Ended March 31	2021		2020		2021		2020
(in millions of U.S. dollars)
Service cost:
Losses and loss expenses	$	—	$	—	$	—	$	—
Administrative expenses	1		1		—		—
Total service cost	1		1		—		—
Non-service cost (benefit):
Losses and loss expenses	(5)		(3)		(2)		(2)
Administrative expenses	(46)		(31)		(18)		(18)
Total non-service cost (benefit)	(51)		(34)		(20)		(20)
Net periodic benefit cost (benefit)	$	(50)	$	(33)	$	(20)	$	(20)

Segment information (Tables)

3 Months Ended

Mar. 31, 2021

Segment Reporting [Abstract]

Operations By Segment

The following tables present the Statement of Operations by segment:


For the Three Months Ended March 31, 2021 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated



Net premiums written	$	3,664	$	1,098	$	183	$	2,890	$	207	$	620	$	—	$	—	$	8,662
Net premiums earned	3,674		1,184		110		2,478		180		595		—		—		8,221
Losses and loss expenses	2,560		819		85		1,263		120		198		9		(1)		5,053
Policy benefits	—		—		—		—		—		163		—		4		167
Policy acquisition costs	514		247		12		668		45		179		—		—		1,665
Administrative expenses	254		60		3		266		8		82		71		—		744
Underwriting income (loss)	346		58		10		281		7		(27)		(80)		(3)		592
Net investment income (loss)	540		65		7		141		70		98		(17)		(41)		863
Other (income) expense	2		1		—		1		—		(34)		(415)		(45)		(490)
Amortization expense of purchased intangibles	—		3		7		12		—		1		49		—		72
Segment income	$	884	$	119	$	10	$	409	$	77	$	104	$	269	$	1	$	1,873
Net realized gains (losses)													888		(1)		887
Interest expense													122		—		122

Income tax expense													338		—		338
Net income													$	697	$	—	$	2,300


For the Three Months Ended March 31, 2020 (in millions of U.S. dollars)	North America Commercial P&C Insurance		North America Personal P&C Insurance		North America Agricultural Insurance		Overseas General Insurance		Global Reinsurance		Life Insurance		Corporate		Segment Measure Reclass		Chubb Consolidated



Net premiums written	$	3,252	$	1,107	$	157	$	2,598	$	218	$	645	$	—	$	—	$	7,977
Net premiums earned	3,376		1,200		94		2,307		186		631		—		—		7,794
Losses and loss expenses	2,181		683		65		1,258		87		202		11		(2)		4,485
Policy benefits	—		—		—		—		—		185		—		(56)		129
Policy acquisition costs	492		245		11		642		45		180		—		—		1,615
Administrative expenses	259		68		4		258		10		76		66		—		741
Underwriting income (loss)	444		204		14		149		44		(12)		(77)		58		824
Net investment income (loss)	525		66		9		145		69		95		(24)		(24)		861
Other (income) expense	6		2		—		4		—		(12)		23		32		55
Amortization expense of purchased intangibles	—		3		7		12		—		1		50		—		73
Segment income (loss)	$	963	$	265	$	16	$	278	$	113	$	94	$	(174)	$	2	$	1,557
Net realized gains (losses)													(956)		(2)		(958)
Interest expense													132		—		132

Income tax expense													215		—		215
Net income (loss)													$	(1,477)	$	—	$	252

Earnings per share (Tables)

3 Months Ended

Mar. 31, 2021

Earnings Per Share [Abstract]

Schedule Of Earnings Per Share, Basic And Diluted


	Three Months Ended
	March 31
(in millions of U.S. dollars, except share and per share data)	2021		2020
Numerator:
Net income	$	2,300	$	252
Denominator:
Denominator for basic earnings per share:
Weighted-average shares outstanding	450,539,568		451,868,658
Denominator for diluted earnings per share:
Share-based compensation plans	2,795,971		2,651,610
Weighted-average shares outstanding and assumed conversions	453,335,539		454,520,268
Basic earnings per share	$	5.10	$	0.56
Diluted earnings per share	$	5.07	$	0.55
Potential anti-dilutive share conversions	1,952,612		3,154,406

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

3 Months Ended

Mar. 31, 2021

Table Text Block Supplement [Abstract]

Condensed Consolidating Balance Sheet

The following table presents the condensed balance sheets of Chubb Limited and Chubb INA Holdings Inc.:


	Chubb Limited (Parent Guarantor) (1)				Chubb INA Holdings Inc. (Subsidiary Issuer)
(in millions of U.S. dollars)	March 31, 2021		December 31, 2020		March 31, 2021		December 31, 2020
Assets
Investments	$	—	$	—	$	206	$	197
Cash	23		84		1		1

Due from subsidiaries and affiliates, net	3,510		3,522		—		—
Other assets	8		10		415		463
Total assets	$	3,541	$	3,616	$	622	$	661
Liabilities
Due to subsidiaries and affiliates, net	$	—	$	—	$	3,079	$	3,008
Affiliated notional cash pooling programs	—		—		361		272

Long-term debt	—		—		14,879		14,948
Trust preferred securities	—		—		308		308
Other liabilities	337		323		1,281		1,418
Total liabilities	337		323		19,908		19,954
Total shareholders’ equity (2)	3,204		3,293		(19,286)		(19,293)
Total liabilities and shareholders’ equity	$	3,541	$	3,616	$	622	$	661

(1)Excludes investment in subsidiary issuer (presented separately).

(2)Total shareholders' equity of Parent Guarantor excludes $55.9 billion and $56.1 billion of investment in subsidiaries, including Subsidiary Issuer, at March 31, 2021 and December 31, 2020, respectively. Total shareholders' equity of Subsidiary Issuer excludes $54.5 billion and $55.2 billion of investment in subsidiaries at March 31, 2021 and December 31, 2020, respectively.

Condensed Consolidating Statement Of Operations and Comprehensive Income

The following table presents the condensed statements of operations and comprehensive income of Chubb Limited and Chubb INA Holdings Inc.:


	Chubb Limited (Parent Guarantor) (1)				Chubb INA Holdings Inc. (Subsidiary Issuer)
Three Months Ended March 31	2021		2020		2021		2020
(in millions of U.S. dollars)
Net investment income (loss)	$	1	$	(2)	$	1	$	4

Net realized gains (loss)	13		(21)		67		113
Administrative expenses	22		24		(52)		(38)
Interest (income) expense	(34)		(34)		145		148
Other (income) expense	(13)		(9)		(5)		8
Income tax expense (benefit)	11		—		(22)		7
Net income (loss) (2)	$	28	$	(4)	$	2	$	(8)
Comprehensive income (loss)	$	28	$	(4)	$	1	$	(38)

(1)Excludes investment in subsidiary issuer (presented separately).

(2)Net income of Parent Guarantor excludes equity in earnings from investment in subsidiaries, including Subsidiary Issuer, of $2,272 million and $256 million for the three months ended March 31, 2021 and 2020, respectively. Net income of Subsidiary Issuer excludes equity in earnings from investment in subsidiaries of $1,031 million and $593 million for the three months ended March 31, 2021 and 2020, respectively.

General Schedule of Cash and Cash Equivalent (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Cash and Cash Equivalents [Line Items]
Cash	$ 1,684	$ 1,747
Restricted cash	157	89
Total cash and restricted cash shown in the Consolidated statement of cash flows	$ 1,841	$ 1,836	$ 1,658	$ 1,646

General Goodwill (Details) $ in Millions	3 Months Ended
General Goodwill (Details) $ in Millions	Mar. 31, 2021 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Period Increase (Decrease)	$ 12

General Adoption of New Accounting Pronouncements (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	$ (59,076)	$ (59,441)	$ (52,197)
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	$ (41,637)	(39,337)	$ (36,331)	$ (36,142)
Retained Earnings [Member] \| Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax		$ 0		$ 63

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

+ References + Details

Acquisitions Investments (Details) - Huatai Group [Member] - CHINA - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2019
Investment Holdings [Line Items]
Equity Method Investment, Ownership Percentage	47.10%
Equity method investment, additional 7.1 percentage agreed on		7.10%
Equity method investment, incremental 0.9 percent obtained	0.90%
Purchase of incremental ownership interest	$ 65

Investments (Narrative) (Detail) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Investments [Line Items]
Restricted assets in fixed maturities and short-term investments	$ 20,800	$ 19,600
Restricted assets in cash	$ 157	$ 89

Investments Investments (Schedule Of Amortized Cost and Fair Value of Available-for-sale Securities and Related OTTI Recognized in AOCI) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 87,873	$ 85,188
Debt Securities, Available-for-sale, Allowance for Credit Loss	(15)	(20)	$ (176)	$ 0
Available for Sale, Gross Unrealized Appreciation	3,801	5,655
Available for Sale, Gross Unrealized Depreciation	(588)	(124)
Available for sale, Fair Value	91,071	90,699
U.S. Treasury / Agency
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,413	2,471
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available for Sale, Gross Unrealized Appreciation	121	199
Available for Sale, Gross Unrealized Depreciation	(7)	0
Available for sale, Fair Value	2,527	2,670
Non-U.S.
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	25,147	24,594
Debt Securities, Available-for-sale, Allowance for Credit Loss	(6)	(6)
Available for Sale, Gross Unrealized Appreciation	1,214	1,808
Available for Sale, Gross Unrealized Depreciation	(189)	(42)
Available for sale, Fair Value	26,166	26,354
Corporate and asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	35,224	34,095
Debt Securities, Available-for-sale, Allowance for Credit Loss	(9)	(14)
Available for Sale, Gross Unrealized Appreciation	1,474	2,322
Available for Sale, Gross Unrealized Depreciation	(289)	(72)
Available for sale, Fair Value	36,400	36,331
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	18,788	17,456
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available for Sale, Gross Unrealized Appreciation	738	1,022
Available for Sale, Gross Unrealized Depreciation	(89)	(8)
Available for sale, Fair Value	19,437	18,470
Municipal
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	6,301	6,572
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available for Sale, Gross Unrealized Appreciation	254	304
Available for Sale, Gross Unrealized Depreciation	(14)	(2)
Available for sale, Fair Value	$ 6,541	$ 6,874

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	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	$ 11,175	$ 11,697
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(43)	(44)	$ (45)	$ 0
Debt securities, held to maturity, net carrying value	11,132	11,653
Held-to-maturity, Gross Unrealized Appreciation	621	859
Held-to-maturity, Gross Unrealized Depreciation	(1)	(2)
Held to maturity, at Fair Value	11,752	12,510
U.S. Treasury / Agency
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	1,158	1,392
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0	0
Debt securities, held to maturity, net carrying value	1,158	1,392
Held-to-maturity, Gross Unrealized Appreciation	39	60
Held-to-maturity, Gross Unrealized Depreciation	0	0
Held to maturity, at Fair Value	1,197	1,452
Non-U.S.
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	1,276	1,295
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(6)	(7)
Debt securities, held to maturity, net carrying value	1,270	1,288
Held-to-maturity, Gross Unrealized Appreciation	82	118
Held-to-maturity, Gross Unrealized Depreciation	(1)	(1)
Held to maturity, at Fair Value	1,351	1,405
Corporate and asset-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	2,163	2,185
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(35)	(35)
Debt securities, held to maturity, net carrying value	2,128	2,150
Held-to-maturity, Gross Unrealized Appreciation	183	288
Held-to-maturity, Gross Unrealized Depreciation	0	0
Held to maturity, at Fair Value	2,311	2,438
Mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	1,888	2,000
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(1)	(1)
Debt securities, held to maturity, net carrying value	1,887	1,999
Held-to-maturity, Gross Unrealized Appreciation	110	148
Held-to-maturity, Gross Unrealized Depreciation	0	(1)
Held to maturity, at Fair Value	1,997	2,146
Municipal
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	4,690	4,825
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(1)	(1)
Debt securities, held to maturity, net carrying value	4,689	4,824
Held-to-maturity, Gross Unrealized Appreciation	207	245
Held-to-maturity, Gross Unrealized Depreciation	0	0
Held to maturity, at Fair Value	$ 4,896	$ 5,069

Investments Investments (held-to-maturity credit quality indicator) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 11,175	$ 11,697
Fixed Maturities Percent of Total Amortized cost	100.00%	100.00%
Standard & Poor's, AAA Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 2,404	$ 2,511
Fixed Maturities Percent of Total Amortized cost	22.00%	22.00%
Standard & Poor's, AA Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 5,815	$ 6,193
Fixed Maturities Percent of Total Amortized cost	52.00%	53.00%
Standard & Poor's, A Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 2,109	$ 2,138
Fixed Maturities Percent of Total Amortized cost	19.00%	18.00%
Standard & Poor's, BBB Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 818	$ 826
Fixed Maturities Percent of Total Amortized cost	7.00%	7.00%
Standard & Poor's, BB Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 28	$ 28
Fixed Maturities Percent of Total Amortized cost	0.00%	0.00%
Other [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 1	$ 1
Fixed Maturities Percent of Total Amortized cost	0.00%	0.00%

Investments (Schedule Of Fixed Maturities By Contractual Maturity) (Detail) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Available for sale, Due in 1 year or less, Fair Value	$ 4,767	$ 4,760
Available for sale, Due after 1 year through 5 years, Fair Value	26,100	26,227
Available for sale, Due after 5 years through 10 years, Fair Value	27,394	27,232
Available for sale, Due after 10 years, Fair Value	13,373	14,010
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	71,634	72,229
Available for sale, Mortgage backed securities, Fair Value	19,437	18,470
Available for sale, Fair Value	91,071	90,699
Debt securities, Held-to-maturity, maturity, allocated and single maturity date, within one year, net carrying value	1,099	1,231
Held to maturity, Due in 1 year or less, Fair Value	1,109	1,240
Held-to-maturity, after one through five years, net carrying value	3,471	3,592
Held to maturity, Due after 1 year through 5, Fair Value	3,613	3,760
Held-to-maturity, after 5 through 10 years, net carrying value	2,918	3,029
Held to maturity, Due after 5 years through 10 years, Fair Value	3,072	3,228
Held-to-maturity, after 10 years, net carrying value	1,757	1,802
Held to maturity, Due after 10 years, Fair Value	1,961	2,136
Debt securities, Held-to-maturity, maturity, allocated and single maturity date, net carrying value	9,245	9,654
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Fair Value	9,755	10,364
Held-to-maturity, MBS, net carrying value	1,887	1,999
Held to maturity, Mortgage backed securities, Fair Value	1,997	2,146
Debt securities, held to maturity, net carrying value	11,132	11,653
Held to maturity, Fair Value	$ 11,752	$ 12,510

Investments (Aggregate Fair Value And Gross Unrealized Loss By Length Of Time Security Has Continuously Been In Unrealized Loss Position) (Detail) - Fixed Maturities [Member] - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 17,585	$ 4,755
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(522)	(75)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,194	758
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(41)	(22)
Debt Securities, Available-for-sale, Unrealized Loss Position	18,779	5,513
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(563)	(97)
U.S. Treasury / Agency
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	220
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(7)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Debt Securities, Available-for-sale, Unrealized Loss Position	220
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(7)
Non-U.S.
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	4,775	1,628
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(161)	(35)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	381	114
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(19)	(5)
Debt Securities, Available-for-sale, Unrealized Loss Position	5,156	1,742
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(180)	(40)
Corporate and asset-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	6,753	2,212
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(254)	(33)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	737	593
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(19)	(14)
Debt Securities, Available-for-sale, Unrealized Loss Position	7,490	2,805
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(273)	(47)
Mortgage-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	5,470	875
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(87)	(6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	62	35
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2)	(2)
Debt Securities, Available-for-sale, Unrealized Loss Position	5,532	910
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(89)	(8)
Municipal
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	367	40
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(13)	(1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	14	16
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1)	(1)
Debt Securities, Available-for-sale, Unrealized Loss Position	381	56
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (14)	$ (2)

Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) - USD ($)
$ in Millions

3 Months Ended

Mar. 31, 2021

Mar. 31, 2020

Fair Value, Option, Changes in Fair Value, Gain (Loss)

$ 887

$ (958)

Foreign exchange gains

76

(68)

319

(685)

Fixed Maturities [Member]

383

(547)

Other

(1)

0

Debt Securities, Available-for-sale, Realized Gain, Excluding Other-than-temporary Impairment

37

77

Debt Securities, Available-for-sale, Realized Loss, Excluding Other-than-temporary Impairment

(19)

(125)

Debt Securities, Allowance for Credit Loss, Period Increase (Decrease)

6

(150)

Debt Securities, Available-For-Sale, Credit Impairment Charges Intent to Sell

^[1]

0

(121)

Debt Securities, Available-for-sale, Realized Gain (Loss)

24

(319)

Equity Securities [Member]

Equity Securities, FV-NI, Realized Gain (Loss)

367

(29)

Other Investments [Member]

Other derivative instruments

38

5

Investment and embedded derivative instruments

(1)

(2)

S&P put options and futures

109

15

Accounting Standards Update 2016-13 [Member]

(44)

125

Debt Securities, Allowance for Credit Loss, Period Increase (Decrease)

$ 4

$ 149

[1]	Relates to certain securities we intended to sell and securities written to market entering default.

Investments Schedule of Gains and Losses on Equity and Other Investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Gain (Loss) on Securities [Line Items]
Realized Investment Gains (Losses)	$ 887	$ (958)
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)	367	(29)
Less: Net gains (losses) recognized from sales of securities	45	(24)
Unrealized gains (losses) recognized for securities still held at reporting date	322	(5)
Other Investments [Member]
Gain (Loss) on Securities [Line Items]
Realized Investment Gains (Losses)	38	5
Less: Net gains (losses) recognized from sales of securities	0	0
Unrealized gains (losses) recognized for securities still held at reporting date	38	5
Equity securities and other investments [Member]
Gain (Loss) on Securities [Line Items]
Realized Investment Gains (Losses)	405	(24)
Less: Net gains (losses) recognized from sales of securities	45	(24)
Unrealized gains (losses) recognized for securities still held at reporting date	$ 360	$ 0

Investments Investments (Rollforward of expected credit-losses, AFS) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 15	$ 176	$ 20		$ 0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	0	2
Debt Securities, Available-for-sale, Allowance for Credit Loss, Recovery	(9)	0
Accounting Standards Update 2016-13 [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss				$ 25
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	$ 4	$ 149

Investments Investments (Rollforward of expected credit losses HTM) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	$ 43	$ 45	$ 44		$ 0
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Recovery	(1)	0
Accounting Standards Update 2016-13 [Member]
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss				$ 44
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Period Increase (Decrease)	$ 0	$ 1

Investments Entities that Calculate Net Asset Value Per Share (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 3,070	$ 3,200
Alternative Investment	7,457	6,770
Financial [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	270	237
Alternative Investment	710	673
Real Estate Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	621	598
Alternative Investment	942	805
Distressed Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	864	970
Alternative Investment	481	358
Private Credit Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	276	270
Alternative Investment	86	88
Private Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	1,039	1,125
Alternative Investment	4,912	4,519
Vintage Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	0	0
Alternative Investment	72	73
Investment Funds Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	0	0
Alternative Investment	$ 254	$ 254
Minimum [Member] \| Financial [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Minimum [Member] \| Real Estate Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Minimum [Member] \| Distressed Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Minimum [Member] \| Private Credit Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	3 years	3 years
Minimum [Member] \| Private Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Minimum [Member] \| Vintage Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	1 year	1 year
Maximum [Member] \| Financial [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	10 years	10 years
Maximum [Member] \| Real Estate Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	11 years	11 years
Maximum [Member] \| Distressed Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	8 years	8 years
Maximum [Member] \| Private Credit Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	8 years	8 years
Maximum [Member] \| Private Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	14 years	14 years
Maximum [Member] \| Vintage Alternative Investments [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years

Investments (Schedule Of Components Of Restricted Assets) (Detail) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Trust funds	$ 13,553	$ 12,305
Deposits with U.S. regulatory authorities	2,424	2,438
Deposits With Non United States Regulatory Authorities	2,917	2,905
Assets pledged under repurchase agreements	1,458	1,462
Other pledged assets	638	584
Total restricted assets	$ 20,990	$ 19,694

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

Mar. 31, 2021

Dec. 31, 2020

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

$ 91,071

$ 90,699

4,405

4,027

3,735

4,345

8,636

7,945

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

2,076

1,844

U.S. Treasury / Agency

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

2,527

2,670

Non-U.S.

Corporate and asset-backed securities

26,166

26,354

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

Mortgage-backed securities

36,400

36,331

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

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

19,437

18,470

Municipal

Fair Value, Recurring [Member] | Level 1

6,541

6,874

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

2,044

2,148

4,330

3,954

2,279

2,866

421

434

^[1]

0

69

35

2

4,493

4,264

13,638

^[2]

13,701

^[1]

79

52

Fair Value, Recurring [Member] | Level 1 | U.S. Treasury / Agency

7

17

86

69

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

Fair Value, Recurring [Member] | Level 1 | Non-U.S.

2,044

2,148

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

Fair Value, Recurring [Member] | Level 1 | Corporate and asset-backed securities

0

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

Fair Value, Recurring [Member] | Level 1 | Mortgage-backed securities

0

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

Fair Value, Recurring [Member] | Level 1 | Municipal

0

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

Fair Value, Recurring [Member] | Level 1 | GLB

0

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

Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross

0

^[3]

Fair Value, Recurring [Member] | Level 2

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

86,714

86,372

0

1,455

1,474

446

438

^[1]

2,076

1,844

0

0

115

124

90,806

^[2]

90,252

^[1]

0

Fair Value, Recurring [Member] | Level 2 | U.S. Treasury / Agency

0

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

Fair Value, Recurring [Member] | Level 2 | Non-U.S.

483

522

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

Fair Value, Recurring [Member] | Level 2 | Corporate and asset-backed securities

25,516

25,808

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

Fair Value, Recurring [Member] | Level 2 | Mortgage-backed securities

34,788

34,758

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

Fair Value, Recurring [Member] | Level 2 | Municipal

19,386

18,410

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

Fair Value, Recurring [Member] | Level 2 | GLB

6,541

6,874

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

Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross

0

^[3]

Fair Value, Recurring [Member] | Level 3

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

2,313

2,179

75

73

1

5

10

^[1]

0

0

0

0

2,399

^[2]

2,267

^[1]

0

Fair Value, Recurring [Member] | Level 3 | U.S. Treasury / Agency

0

760

1,089

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

Fair Value, Recurring [Member] | Level 3 | Non-U.S.

0

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

Fair Value, Recurring [Member] | Level 3 | Corporate and asset-backed securities

650

546

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

Fair Value, Recurring [Member] | Level 3 | Mortgage-backed securities

1,612

1,573

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

Fair Value, Recurring [Member] | Level 3 | Municipal

51

60

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

Fair Value, Recurring [Member] | Level 3 | GLB

0

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

Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross

760

1,089

^[3]

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

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

91,071

90,699

4,405

4,027

3,735

4,345

877

882

^[1]

2,076

1,844

69

35

2

4,608

4,388

106,843

^[2]

106,220

^[1]

79

52

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

7

17

846

1,158

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

Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Non-U.S.

2,527

2,670

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

Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Corporate and asset-backed securities

26,166

26,354

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

Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Mortgage-backed securities

36,400

36,331

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

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

19,437

18,470

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

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

6,541

6,874

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

Liabilities for Guarantees on Long-Duration Contracts, Guaranteed Benefit Liability, Gross

760

1,089

^[3]

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

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

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

7,457

6,770

Policy Loans [Member]

Other Investments [Member]

232

233

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

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

$ 70

$ 60

[1]	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $6,770 million, policy loans of $233 million and other investments of $60 million at December 31, 2020 measured using NAV as a practical expedient.
[2]	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $7,457 million, policy loans of $232 million and other investments of $70 million at March 31, 2021 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.

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

3 Months Ended

Mar. 31, 2021

Dec. 31, 2020

Mar. 31, 2020

^[3]

Dec. 31, 2019

^[3]

Fair Value Measurements, Valuation Processes, Description

Actuarial model

Weighted Average [Member]

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

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

^[1]

4.60%

Significant Unobservable Inputs Annuitization Rate

^[1]

3.40%

Minimum [Member]

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

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

3.00%

Significant Unobservable Inputs Annuitization Rate

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

34.00%

Significant Unobservable Inputs Annuitization Rate

100.00%

Level 3 | GLB

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

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

$ 760

^[2]

$ 1,089

^[2]

$ 1,591

$ 897

Level 3 | Fair Value, Recurring [Member] | GLB

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

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

$ 1,089

[1]	The weighted average lapse and annuitization rates are determined by weighting each treaty's rates by the GLB contracts fair value.
[2]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.
[3]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value.

Fair Value Measurements (Assets and Liabilities, Measured At Fair Value Using Significant Unobservable Inputs) (Detail) - Level 3 - USD ($)
$ in Millions

3 Months Ended

Mar. 31, 2021

Mar. 31, 2020

Equity Securities [Member]

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

$ 73

$ 69

0

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

0

0

1

2

(2)

3

(3)

(4)

0

Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets

0

2

(2)

Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets

0

Short-term Investments [Member]

75

67

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

5

6

0

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

0

0

0

1

0

(5)

(6)

Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets

0

0

Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets

0

Other Investments [Member]

1

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

10

0

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

0

0

Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets

0

0

0

0

0

0

Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets

0

Available-for-sale Securities [Member] | Non-U.S.

10

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

546

449

0

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

(3)

8

(14)

0

(2)

121

82

(7)

(46)

(18)

(1)

Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets

0

0

Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets

10

(15)

Available-for-sale Securities [Member] | Corporate and asset-backed securities

650

465

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

1,573

1,451

17

91

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

(1)

6

45

(3)

(13)

169

139

(25)

(19)

(125)

(101)

Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets

0

(3)

(14)

Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets

11

(44)

Available-for-sale Securities [Member] | Mortgage-backed securities

1,612

1,502

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

60

0

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

0

0

0

0

0

(9)

0

Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets

0

0

Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Assets

0

Guaranteed Minimum Income Benefit [Member]

51

60

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

Balance - Beginning of Period, Liabilities

1,089

^[1]

897

^[2]

Transfers into level 3, liability

0

Transfers out of Level 3, Liabilities

0

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

0

Net Realized Gains/(Losses), Liabilities

(319)

^[1]

685

^[2]

Purchases, Liabilities

0

Sales, Liabilities

0

Settlements, Liabilities

0

Other, Liabilities

(10)

9

Balance - End of Period, Liabilities

760

^[1]

1,591

^[2]

Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Liabilities

(319)

^[1]

685

^[2]

Change in Net Unrealized Gains/Losses included in OCI at the Balance Sheet Date, Liabilities

$ 0

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

Fair Value Measurements (Carrying Values And Fair Values Of Financial Instruments Not Measured At Fair Value) (Detail) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	$ 11,752	$ 12,510
Debt Securities, Held-to-maturity	11,175	11,697
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	1,405	1,405
Long-term debt	14,879	14,948
Total liabilities	132,901	131,333
Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	1,144	1,395
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	0	0
Long-term Debt, Fair Value	0	0
Trust preferred securities	0	0
Total liabilities	0	0
Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	10,608	11,115
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	1,405	1,405
Long-term Debt, Fair Value	16,408	17,487
Trust preferred securities	470	473
Total liabilities	18,283	19,365
Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	0	0
Long-term Debt, Fair Value	0	0
Trust preferred securities	0	0
Total liabilities	0	0
Estimate of Fair Value Measurement [Member]
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	1,405	1,405
Long-term Debt, Fair Value	16,408	17,487
Trust preferred securities	470	473
Total liabilities	18,283	19,365
Reported Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	11,132	11,653
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Repurchase agreements	1,405	1,405
Trust preferred securities	308	308
Long-term debt	14,879	14,948
Total liabilities	16,592	16,661
U.S. Treasury / Agency
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	1,197	1,452
Debt Securities, Held-to-maturity	1,158	1,392
U.S. Treasury / Agency \| Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	1,144	1,395
U.S. Treasury / Agency \| Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	53	57
U.S. Treasury / Agency \| Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
U.S. Treasury / Agency \| Reported Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	1,158	1,392
Non-U.S.
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	1,351	1,405
Debt Securities, Held-to-maturity	1,276	1,295
Non-U.S. \| Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
Non-U.S. \| Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	1,351	1,405
Non-U.S. \| Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
Non-U.S. \| Reported Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	1,270	1,288
Corporate and asset-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	2,311	2,438
Debt Securities, Held-to-maturity	2,163	2,185
Corporate and asset-backed securities \| Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
Corporate and asset-backed securities \| Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	2,311	2,438
Corporate and asset-backed securities \| Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
Corporate and asset-backed securities \| Reported Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	2,128	2,150
Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	1,997	2,146
Debt Securities, Held-to-maturity	1,888	2,000
Mortgage-backed securities \| Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
Mortgage-backed securities \| Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	1,997	2,146
Mortgage-backed securities \| Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
Mortgage-backed securities \| Reported Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	1,887	1,999
Municipal
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	4,896	5,069
Debt Securities, Held-to-maturity	4,690	4,825
Municipal \| Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
Municipal \| Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	4,896	5,069
Municipal \| Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held to maturity, Fair Value	0	0
Municipal \| Reported Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Debt Securities, Held-to-maturity	$ 4,689	$ 4,824

Reinsurance (Reinsurance Recoverable on Ceded Reinsurance) (Details) - USD ($)
$ in Millions

Mar. 31, 2021

Dec. 31, 2020

Mar. 31, 2020

Dec. 31, 2019

Ceded Credit Risk [Line Items]

Reinsurance Recoverable for Unpaid Claims and Claims Adjustments

$ 14,860

^[1]

$ 14,647

$ 14,040

^[1]

$ 14,181

Reinsurance Recoverable for Paid Claims and Claims Adjustments

1,054

945

Reinsurance recoverable on losses and loss expenses, net of valuation allowance - $317 and $314

15,914

15,592

Reinsurance recoverable on policy benefits

202

206

Reinsurance Recoverables on Unpaid Losses, Allowance

258

257

Reinsurance Recoverables on Paid Losses, Allowance

59

57

Reinsurance Recoverable, Allowance for Credit Loss

317

314

$ 305

$ 316

Reinsurance Recoverables on Future Policy Benefits, Allowance

$ 4

$ 5

[1]	Net of valuation allowance for uncollectible reinsurance.

Reinsurance (Details) - USD ($) $ in Millions	3 Months Ended
Reinsurance (Details) - USD ($) $ in Millions	Mar. 31, 2021	Mar. 31, 2020
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Reinsurance Recoverable, Allowance for Credit Loss, Beginning of period	$ 314	$ 316
Reinsurance Recoverable, Credit Loss Expense (Reversal)	3	2
Reinsurance, Loss on Uncollectible Accounts in Period, Amount	0	(13)
Reinsurance Recoverable, Allowance for Credit Loss, end of period	$ 317	$ 305

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

3 Months Ended

Mar. 31, 2021

Mar. 31, 2020

Unpaid Losses and Loss Expenses [Roll Forward]

Gross unpaid losses and loss expenses – beginning of period

$ 67,811

$ 62,690

Reinsurance recoverable on unpaid losses – beginning of period (1)

(14,647)

(14,181)

Net unpaid losses and loss expenses – beginning of period

53,164

48,509

Current Year Claims and Claims Adjustment Expense

5,249

4,605

Prior Year Claims and Claims Adjustment Expense

^[1]

(196)

(120)

Total, Incurred

5,053

4,485

Net loss and loss expenses paid, Current Year

732

920

Net loss and loss expenses paid, Prior Years

3,161

3,335

Total, Paid

3,893

4,255

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

71

(565)

Net unpaid losses and loss expenses – end of period

54,395

48,174

Reinsurance recoverable on unpaid losses (1)

^[2]

14,860

14,040

Gross unpaid losses and loss expenses – end of period

69,255

62,214

prior period development, net adjustments

4

$ 2

Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease), Gross

1,444

Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease)

$ 1,231

[1]	Relates to prior period loss reserve development only and excludes prior period development related to reinstatement premiums, expense adjustments and earned premiums totaling $4 million and $2 million for the three months ended March 31, 2021 and 2020, respectively.
[2]	Net of valuation allowance for uncollectible reinsurance.

Unpaid losses and loss expenses Unpaid losses and loss expenses (PPD table) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	$ (192)	$ (118)
North America Commercial P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(127)	(105)
North America Personal P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		1
North American Agriculture Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(2)	(14)
Overseas General Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(25)	(4)
Global Reinsurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(7)	(7)
Corporate Segment [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	9	11
Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(155)	(86)
Short Tail [Member] \| North America Commercial P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(81)	(62)
Short Tail [Member] \| North America Personal P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(40)	1
Short Tail [Member] \| North American Agriculture Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(2)	(14)
Short Tail [Member] \| Overseas General Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(25)	(4)
Short Tail [Member] \| Global Reinsurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(7)	(7)
Short Tail [Member] \| Corporate Segment [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(37)	(32)
Long Tail [Member] \| North America Commercial P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(46)	(43)
Long Tail [Member] \| North America Personal P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
Long Tail [Member] \| North American Agriculture Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
Long Tail [Member] \| Overseas General Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
Long Tail [Member] \| Global Reinsurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
Long Tail [Member] \| Corporate Segment [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	$ 9	$ 11

Unpaid losses and loss expenses Unpaid losses and loss expenses (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	$ (192)	$ (118)
Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(37)	(32)
Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(155)	(86)
North America Commercial P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(127)	(105)
North America Commercial P&C Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(46)	(43)
North America Commercial P&C Insurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(81)	(62)
North America Commercial P&C Insurance [Member] \| Professional Malpractice Liability Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(51)
North America Commercial P&C Insurance [Member] \| Environmental lines [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(35)
North America Commercial P&C Insurance [Member] \| Commercial Excess and Umbrella [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	57	49
North America Commercial P&C Insurance [Member] \| General Liability [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		23
North America Commercial P&C Insurance [Member] \| Accident years 2016 and prior [Member] \| Professional Malpractice Liability Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		(66)
North America Commercial P&C Insurance [Member] \| Accident years 2016 and prior [Member] \| Environmental lines [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		(43)
North America Commercial P&C Insurance [Member] \| Accident years 2016 and prior [Member] \| Workers' Compensation Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		(28)
North America Commercial P&C Insurance [Member] \| Short-duration Insurance Contracts, Accident Year 2018 [Member] \| Surety Product Line [Member] \| Short Tail [Member] \| Catastrophe [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		(31)
North America Commercial P&C Insurance [Member] \| Accident years 2018 - 2019 [Member] \| Surety Product Line [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(49)
North America Commercial P&C Insurance [Member] \| Accident years 2018 - 2019 [Member] \| Accident and Health Insurance Product Line [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		(36)
North America Commercial P&C Insurance [Member] \| Short-Duration Insurance Contract, Accident Year 2020 \| Property and Inland Marine [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(25)
North America Commercial P&C Insurance [Member] \| Accident Years 2019 - 2020 \| Professional Malpractice Liability Insurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	41
North America Commercial P&C Insurance [Member] \| Accident Years 2019 - 2020 \| Accident and Health Insurance Product Line [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(48)
North America Agricultural Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(2)	(14)
North America Agricultural Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
North America Agricultural Insurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(2)	(14)
Corporate Segment [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	9	11
Corporate Segment [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	9	11
Corporate Segment [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
Overseas General Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(25)	(4)
Overseas General Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
Overseas General Insurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(25)	(4)
North America Personal P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		1
North America Personal P&C Insurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
North America Personal P&C Insurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(40)	1
North America Personal P&C Insurance [Member] \| Short-Duration Insurance Contract, Accident Year 2020
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(40)
Global Reinsurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(7)	(7)
Global Reinsurance [Member] \| Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0
Global Reinsurance [Member] \| Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	$ (7)	$ (7)

Commitments, Contingencies, And Guarantees (Narrative) (Detail) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Financial Instruments Owned and Pledged as Collateral [Line Items]
Derivative liability subject to a master netting agreement	$ 12	$ 30
Repurchase agreements	1,405	1,405
Purchase Commitment, Remaining Minimum Amount Committed	591
Carrying value of limited partnerships and partially-owned investment companies included in other investments	7,200	6,500
Funding commitments relating to limited partnerships and partially-owned investment companies	3,100	3,200
Unrecognized tax benefits	62
Operating Lease, Right-of-Use Asset	448	473
Operating Lease, Liability	$ 490	$ 517

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

Mar. 31, 2021

Dec. 31, 2020

Foreign currency forward contracts

Options/Futures contracts on notes, bonds, and equities

$ 3,657

$ 2,807

2,063

1,749

Convertible securities

Total investment and embedded derivative instruments

^[1]

13

11

80

44

(79)

(52)

Futures contracts on equities

5,733

4,567

^[2]

761

709

Other

Other Derivative Instruments [Member]

52

16

Guaranteed Minimum Income Benefit [Member]

813

725

^[3]

0

Other Assets [Member] | Foreign currency forward contracts

^[3]

1,506

1,658

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

21

22

Other Assets [Member] | Futures contracts on equities

48

13

Other Assets [Member] | Other

^[2]

0

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

2

0

Fixed Maturities [Member] | Convertible securities

2

0

Equity Securities [Member] | Convertible securities

^[1]

11

9

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

^[1]

0

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

(69)

(49)

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

(10)

(3)

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

^[2]

(7)

(17)

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

0

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

(7)

(17)

Derivative Instruments, Gain (Loss) [Line Items]

^[3]

$ (760)

$ (1,089)

[1]	Includes fair value of embedded derivatives.
[2]	Related to GMDB and GLB book of business.
[3]	Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.

Commitments, Contingencies, And Guarantees (Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations) (Detail) - USD ($)
$ in Millions

3 Months Ended

Mar. 31, 2021

Mar. 31, 2020

Foreign currency forward contracts

$ 383

$ (547)

Derivative Instruments, Gain (Loss) [Line Items]

All Other Futures Contracts, Options and equities [Member]

(16)

43

Derivative Instruments, Gain (Loss) [Line Items]

Derivative Instruments, Gain (Loss) [Line Items]

125

(27)

Convertible securities

Total investment and embedded derivative instruments

^[1]

0

(1)

Derivative Instruments, Gain (Loss) [Line Items]

Derivative Instruments, Gain (Loss) [Line Items]

109

15

GLB

Futures contracts on equities

319

(685)

Derivative Instruments, Gain (Loss) [Line Items]

Derivative Instruments, Gain (Loss) [Line Items]

^[2]

(44)

125

Other

Guaranteed Living Benefit And Other Derivative Instruments [Member]

(1)

(2)

Derivative Instruments, Gain (Loss) [Line Items]

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

$ 274

$ (562)

[1]	Includes embedded derivatives.
[2]	Related to GMDB and GLB book of business.

Commitments, contingencies, and guarantees Commitments, Contingencies, And Guarantees (Transactions accounted for as secured borrowings) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	$ 2,076	$ 1,844
Securities lending payable	2,076	1,844
Cash [Member] \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	732	551
U.S. Treasury / Agency \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	116	148
Foreign [Member] \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	1,068	1,032
Corporate and asset-backed securities \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	21	30
Mortgage-backed securities \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	1	4
Equity Securities [Member] \| Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	$ 138	$ 79

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

Mar. 31, 2021

Dec. 31, 2020

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

$ 1,458

$ 1,462

Repurchase agreements

1,405

Cash [Member]

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

10

4

U.S. Treasury / Agency

Mortgage-backed securities

106

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

Repurchase Agreements [Member]

1,342

1,352

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

Secured Borrowings, Gross, Difference, Amount

^[1]

53

57

Maturity 30 to 90 Days [Member]

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

Maturity 30 to 90 Days [Member] | Cash [Member]

102

481

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

Maturity 30 to 90 Days [Member] | U.S. Treasury / Agency

0

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

Maturity 30 to 90 Days [Member] | Mortgage-backed securities

102

0

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

Maturity Greater than 90 Days [Member]

0

481

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

Maturity Greater than 90 Days [Member] | Cash [Member]

1,356

981

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

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

10

4

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

Maturity Greater than 90 Days [Member] | Mortgage-backed securities

4

106

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

$ 1,342

$ 871

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

Shareholders' equity (Details) - SFr / shares	3 Months Ended
Shareholders' equity (Details) - SFr / shares	Mar. 31, 2021	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Common Shares, par value	SFr 24.15	SFr 24.15
Common Shares in treasury, shares	27,928,305	26,872,639
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures	2,054,334

Shareholders' equity Dividends Declared (Details)	3 Months Ended
Shareholders' equity Dividends Declared (Details)	Mar. 31, 2021 $ / shares	Mar. 31, 2021 SFr / shares	Mar. 31, 2020 $ / shares	Mar. 31, 2020 SFr / shares	May 20, 2020 $ / shares	May 31, 2019 $ / shares
Equity, Class of Treasury Stock [Line Items]
Annual dividend per share approved by shareholders					$ 3.12	$ 3.00
Common Stock, Dividend Rate Approved					$ 0.78	$ 0.75
United States of America, Dollars
Equity, Class of Treasury Stock [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.78		$ 0.75
Switzerland, Francs
Equity, Class of Treasury Stock [Line Items]
Common Stock, Dividends, Per Share, Declared \| SFr / shares		SFr 0.70		SFr 0.72

Shareholders' equity Share Repurchases (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Apr. 29, 2021	Mar. 31, 2021	Mar. 31, 2020	Feb. 01, 2021	Nov. 19, 2020	Nov. 21, 2019
Nov 2019 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount						$ 1,500
Number of shares repurchased			2,266,150
Cost of shares repurchased			$ 326
Repurchase authorization remaining at end of period			$ 1,124
Nov 2020 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount				$ 2,500	$ 1,500
Number of shares repurchased		3,110,000
Cost of shares repurchased		$ 519
Repurchase authorization remaining at end of period		$ 1,982
CB_Increase(Decrease)StockRepurchaseProgramAuthorizedAmount				$ 1,000
Subsequent Event [Member] \| Nov 2020 Stock Repurchase Plan
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased	450,000
Cost of shares repurchased	$ 76
Repurchase authorization remaining at end of period	$ 1,906

Share-Based Compensation (Detail) - $ / shares		3 Months Ended
Share-Based Compensation (Detail) - $ / shares	Feb. 25, 2021	Mar. 31, 2021
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period in years		3 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period		3 years
Award term period in years		10 years
Stock options granted	1,790,056
Weighted-average grant date fair value for stock options granted	$ 33.05
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	848,762
Grant date fair value of awards except for options granted to employees and officers of the company	$ 164.94
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	284,766
Grant date fair value of awards except for options granted to employees and officers of the company	$ 164.94
Restricted Stock Units (RSUs) [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	324,142
Grant date fair value of awards except for options granted to employees and officers of the company	$ 164.94

Postretirement benefits Components of net periodic benefit costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	$ 1	$ 1
Non-service cost (benefit)	(51)	(34)
Net periodic benefit cost (benefit)	(50)	(33)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0
Interest cost	0	1
Expected return on plan assets	0	(1)
Defined Benefit Plan, Amortization of Gain (Loss)	0	0
Amortization of prior service cost	(20)	(20)
Settlements	0	0
Non-service cost (benefit)	(20)	(20)
Net periodic benefit cost (benefit)	(20)	(20)
Losses and loss expenses \| Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0
Non-service cost (benefit)	(5)	(3)
Losses and loss expenses \| Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0
Non-service cost (benefit)	(2)	(2)
Administrative Expense \| Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	1	1
Non-service cost (benefit)	(46)	(31)
Administrative Expense \| Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0
Non-service cost (benefit)	(18)	(18)
Foreign Plan [Member] \| Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	1	1
Interest cost	5	6
Expected return on plan assets	(11)	(10)
Defined Benefit Plan, Amortization of Gain (Loss)	1	0
Amortization of prior service cost	0	0
Settlements	0	0
Non-service cost (benefit)	(5)	(4)
Net periodic benefit cost (benefit)	(4)	(3)
UNITED STATES \| Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0
Interest cost	18	25
Expected return on plan assets	(64)	(56)
Defined Benefit Plan, Amortization of Gain (Loss)	0	0
Amortization of prior service cost	0	0
Settlements	0	1
Non-service cost (benefit)	(46)	(30)
Net periodic benefit cost (benefit)	$ (46)	$ (30)

Segment information Segment Information (narrative Detail (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Gain (Loss) on Derivative	$ (383)	$ 547
Net investment income	863	861
North America Agricultural Insurance [Member]
Segment Reporting Information [Line Items]
Net investment income	7	9
Segment Life [Member]
Segment Reporting Information [Line Items]
Net investment income	$ 98	$ 95

Segment Information (Operations By Segment) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Net premiums written	$ 8,662	$ 7,977
Net premiums earned	8,221	7,794
Losses and loss expenses	5,053	4,485
Policy benefits	167	129
Policy acquisition costs	1,665	1,615
Administrative expenses	744	741
Underwriting income (loss)	592	824
Net investment income (loss)	863	861
Other (income) expense	(490)	55
Amortization of purchased intangibles	72	73
Segment Income (loss)	1,873	1,557
Realized Investment Gains (Losses)	887	(958)
Interest expense	122	132
Income tax expense	338	215
Net income	2,300	252
Segment Reconciling Items
Segment Reporting Information [Line Items]
Net premiums written	0	0
Net premiums earned	0	0
Losses and loss expenses	(1)	(2)
Policy benefits	4	(56)
Policy acquisition costs	0	0
Administrative expenses	0	0
Underwriting income (loss)	(3)	58
Net investment income (loss)	(41)	(24)
Other (income) expense	(45)	32
Amortization of purchased intangibles	0	0
Segment Income (loss)	1	2
Realized Investment Gains (Losses)	(1)	(2)
Interest expense	0	0
Income tax expense	0	0
Net income	0	0
North America Commercial P&C Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	3,664	3,252
Net premiums earned	3,674	3,376
Losses and loss expenses	2,560	2,181
Policy benefits	0	0
Policy acquisition costs	514	492
Administrative expenses	254	259
Underwriting income (loss)	346	444
Net investment income (loss)	540	525
Other (income) expense	2	6
Amortization of purchased intangibles	0	0
Segment Income (loss)	884	963
North America Personal P&C Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	1,098	1,107
Net premiums earned	1,184	1,200
Losses and loss expenses	819	683
Policy benefits	0	0
Policy acquisition costs	247	245
Administrative expenses	60	68
Underwriting income (loss)	58	204
Net investment income (loss)	65	66
Other (income) expense	1	2
Amortization of purchased intangibles	3	3
Segment Income (loss)	119	265
North America Agricultural Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	183	157
Net premiums earned	110	94
Losses and loss expenses	85	65
Policy benefits	0	0
Policy acquisition costs	12	11
Administrative expenses	3	4
Underwriting income (loss)	10	14
Net investment income (loss)	7	9
Other (income) expense	0	0
Amortization of purchased intangibles	7	7
Segment Income (loss)	10	16
Overseas General Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	2,890	2,598
Net premiums earned	2,478	2,307
Losses and loss expenses	1,263	1,258
Policy benefits	0	0
Policy acquisition costs	668	642
Administrative expenses	266	258
Underwriting income (loss)	281	149
Net investment income (loss)	141	145
Other (income) expense	1	4
Amortization of purchased intangibles	12	12
Segment Income (loss)	409	278
Global Reinsurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	207	218
Net premiums earned	180	186
Losses and loss expenses	120	87
Policy benefits	0	0
Policy acquisition costs	45	45
Administrative expenses	8	10
Underwriting income (loss)	7	44
Net investment income (loss)	70	69
Other (income) expense	0	0
Amortization of purchased intangibles	0	0
Segment Income (loss)	77	113
Life Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	620	645
Net premiums earned	595	631
Losses and loss expenses	198	202
Policy benefits	163	185
Policy acquisition costs	179	180
Administrative expenses	82	76
Underwriting income (loss)	(27)	(12)
Net investment income (loss)	98	95
Other (income) expense	(34)	(12)
Amortization of purchased intangibles	1	1
Segment Income (loss)	104	94
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Net premiums written	0	0
Net premiums earned	0	0
Losses and loss expenses	9	11
Policy benefits	0	0
Policy acquisition costs	0	0
Administrative expenses	71	66
Underwriting income (loss)	(80)	(77)
Net investment income (loss)	(17)	(24)
Other (income) expense	(415)	23
Amortization of purchased intangibles	49	50
Segment Income (loss)	269	(174)
Realized Investment Gains (Losses)	888	(956)
Interest expense	122	132
Income tax expense	338	215
Net income	$ 697	$ (1,477)

Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income	$ 2,300	$ 252
Weighted-average shares outstanding	450,539,568	451,868,658
Share-based compensation plans	2,795,971	2,651,610
Weighted-average shares outstanding and assumed conversions	453,335,539	454,520,268
Basic earnings per share (US$ per share)	$ 5.10	$ 0.56
Diluted earnings per share (US$ per share)	$ 5.07	$ 0.55
Potential anti-dilutive share conversions	1,952,612	3,154,406

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Condensed Balance Sheet Statements, Captions [Line Items]

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

Mar. 31, 2021

Dec. 31, 2020

Mar. 31, 2020

Trust preferred securities

$ 118,979

$ 118,669

Cash

1,684

1,747

Total assets

191,977

190,774

Long-term debt

14,879

14,948

308

Total liabilities

132,901

131,333

Total shareholders' equity

59,076

59,441

$ 52,197

Total liabilities and shareholders’ equity

191,977

190,774

Chubb Limited (Parent Guarantor)

Condensed Balance Sheet Statements, Captions [Line Items]

Due from subsidiaries and affiliates, net

^[1]

0

Cash

^[1]

23

84

^[1]

3,510

3,522

Other assets

^[1]

8

10

Total assets

^[1]

3,541

3,616

Due to subsidiaries and affiliates, net

^[1]

0

Affiliated notional cash pooling programs

^[1]

0

Long-term debt

^[1]

0

Trust preferred securities

^[1]

0

Other liabilities

^[1]

337

323

Total liabilities

^[1]

337

323

Total shareholders' equity

^[1],[2]

3,204

3,293

Total liabilities and shareholders’ equity

^[1]

3,541

3,616

Investments in subsidiaries

55,900

56,100

Chubb INA Holdings Inc (Subsidiary Issuer)

Condensed Balance Sheet Statements, Captions [Line Items]

Due from subsidiaries and affiliates, net

206

197

Cash

1

0

Other assets

415

463

Total assets

622

661

Due to subsidiaries and affiliates, net

3,079

3,008

Affiliated notional cash pooling programs

361

272

Long-term debt

14,879

14,948

Trust preferred securities

308

Other liabilities

1,281

1,418

Total liabilities

19,908

19,954

Total shareholders' equity

^[2]

(19,286)

(19,293)

Total liabilities and shareholders’ equity

622

661

Investments in subsidiaries

$ 54,500

$ 55,200

[1]	Excludes investment in subsidiary issuer (presented separately).
[2]	Total shareholders' equity of Parent Guarantor excludes $55.9 billion and $56.1 billion of investment in subsidiaries, including Subsidiary Issuer, at March 31, 2021 and December 31, 2020, respectively. Total shareholders' equity of Subsidiary Issuer excludes $54.5 billion and $55.2 billion of investment in subsidiaries at March 31, 2021 and December 31, 2020, respectively.

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

3 Months Ended

Mar. 31, 2021

Mar. 31, 2020

Condensed Statement of Income Captions [Line Items]

Net investment income

$ 863

$ 861

Interest (income) expense

887

(958)

Administrative expenses

(744)

(741)

(122)

(132)

Other (income) expense

(490)

55

Income tax expense

(338)

(215)

Net income

2,300

252

Comprehensive income (loss)

389

(2,460)

Chubb Limited (Parent Guarantor)

Condensed Statement of Income Captions [Line Items]

Net investment income

^[1]

1

(2)

Interest (income) expense

^[1]

13

(21)

Administrative expenses

^[1]

22

24

^[1]

(34)

Other (income) expense

^[1]

(13)

(9)

Income tax expense

^[1]

11

0

Net income

^[1],[2]

28

(4)

Comprehensive income (loss)

^[1]

28

(4)

Equity In Earnings Of Subsidiaries

2,272

256

Chubb INA Holdings Inc (Subsidiary Issuer)

Condensed Statement of Income Captions [Line Items]

Net investment income

1

4