Chubb Limited (CB) 10-Q 31 Jul 20 2020 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - SFr / shares	6 Months Ended
	Jun. 30, 2020	Jul. 17, 2020	Dec. 31, 2019
Document Type	10-Q
Document Period End Date	Jun. 30, 2020
Document Quarterly Report	true
Document Transition Report	false
Entity Registrant Name	Chubb Ltd
Entity Central Index Key	0000896159
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Entity File Number	1-11778
Entity Incorporation, State or Country Code	V8
Entity Tax Identification Number	98-0091805
Entity Address, Address Line One	Baerengasse 32
Entity Address, City or Town	Zurich
Entity Address, Country	CH
Entity Address, Postal Zip Code	8001
Country Region	41
City Area Code	(0)43
Local Phone Number	456 76 00
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Shell Company	false
Entity Emerging Growth Company	false
Common Shares, par value	SFr 24.15		SFr 24.15
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Common Shares Outstanding		451,365,891
INA Senior Notes Due March 2038 [Member]
Title of 12(b) Security	Guarantee of Chubb INA Holdings Inc. 2.50% Senior Notes due 2038
Trading Symbol	CB/38A
Security Exchange Name	NYSE
INA Senior Notes Due December 2029 [Member]
Title of 12(b) Security	Guarantee of Chubb INA Holdings Inc. 0.875% Senior Notes due 2029
Trading Symbol	CB/29A
Security Exchange Name	NYSE
INA Senior Notes Due June 2031 [Member]
Title of 12(b) Security	Guarantee of Chubb INA Holdings Inc. 1.40% Senior Notes due 2031
Trading Symbol	CB/31
Security Exchange Name	NYSE
INA Senior Notes Due March 2028 [Member]
Title of 12(b) Security	Guarantee of Chubb INA Holdings Inc. 1.55% Senior Notes due 2028
Trading Symbol	CB/28
Security Exchange Name	NYSE
INA Senior Notes Due June 2027 [Member]
Title of 12(b) Security	Guarantee of Chubb INA Holdings Inc. 0.875% Senior Notes due 2027
Trading Symbol	CB/27
Security Exchange Name	NYSE
INA Senior Notes Due December 2024 [Member]
Title of 12(b) Security	Guarantee of Chubb INA Holdings Inc. 0.30% Senior Notes due 2024
Trading Symbol	CB/24A
Security Exchange Name	NYSE
Common Class A [Member]
Title of 12(b) Security	Common Shares, par value CHF 24.15 per share
Trading Symbol	CB
Security Exchange Name	NYSE

Consolidated Balance Sheets

Consolidated Balance Sheets $ in Millions	Jun. 30, 2020USD ($)shares		Dec. 31, 2019USD ($)shares
Assets
Fixed maturities available for sale, at fair value, net of valuation allowance - $69 at June 30, 2020 (amortized cost – $82,740 and $82,580)	$ 86,712		$ 85,488
Fixed maturities held to maturity, net carrying value	11,845
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)	11,896		12,581
Equity securities, at fair value	2,394		812
Short-term investments, at fair value (amortized cost - $4,004 and $4,291)	4,003		4,291
Other investments, at fair value	5,923		6,062
Total investments	110,877		109,234
Cash	1,557	[1]	1,537	[2]
Restricted cash	152		109
Securities lending collateral	1,832		994
Accrued investment income	845		867
Insurance and reinsurance balances receivable	10,853		10,357
Reinsurance recoverable on losses and loss expenses, net of valuation allowance - $303 and $316	15,207		15,181
Reinsurance recoverable on policy benefits	197		197
Deferred policy acquisition costs	5,243		5,242
Value of business acquired	290		306
Goodwill	15,184		15,296
Other intangible assets	5,909		6,063
Prepaid reinsurance premiums	2,725		2,647
Investments in partially-owned insurance companies	1,364		1,332
Other assets	9,239		7,581
Total assets	181,474		176,943
Liabilities
Unpaid losses and loss expenses	65,699		62,690
Unearned premiums	17,081		16,771
Future policy benefits	5,895		5,814
Insurance and reinsurance balances payable	6,249		6,184
Securities lending payable	1,832		994
Accounts payable, accrued expenses, and other liabilities	12,589		11,773
Deferred tax liabilities	696		804
Repurchase agreements	1,409		1,416
Short-term debt	1,300		1,299
Long-term debt	13,656		13,559
Trust preferred securities	308		308
Total liabilities	126,714		121,612
Commitments and contingencies (refer to Note 7)
Shareholders’ equity
Common Shares (CHF 24.15 par value; 479,783,864 shares issued; 451,360,023 and 451,971,567 shares outstanding)	11,121		11,121
Common Shares in treasury (28,423,841 and 27,812,297 shares)	(3,866)		(3,754)
Additional Paid in Capital, Common Stock	10,416		11,203
Retained earnings	35,991		36,142
Accumulated other comprehensive income (AOCI)	1,098		619
Total shareholders’ equity	54,760		55,331
Total liabilities and shareholders’ equity	181,474		176,943
Available for sale, at amortized cost	82,740		82,580
Debt Securities, Available-for-sale, Allowance for Credit Loss	69		0
Held-to-maturity, Fair Value	12,620		13,005
Debt Securities, Held-to-maturity, Allowance for Credit Loss	51		0
short-term investments, allowance for credit loss	2
short-term investments amortized cost	4,004		4,291
Reinsurance Recoverable, Allowance for Credit Loss	$ 303		$ 316
Common Shares, shares outstanding | shares	451,360,023		451,971,567
Common Shares, shares issued | shares	479,783,864		479,783,864
Common Shares in treasury, shares | shares	28,423,841		27,812,297
[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to the 2019 Form 10-K for additional information.

Consolidated Statements Of Oper

Consolidated Statements Of Operations and Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues
Net premiums written	$ 8,355	$ 8,343	$ 16,332	$ 15,656
Increase in unearned premiums	(227)	(452)	(410)	(628)
Net premiums earned	8,128	7,891	15,922	15,028
Net investment income	827	859	1,688	1,695
Net realized gains (losses):
Other-than-temporary impairment (OTTI) losses gross	0	(14)	0	(27)
Portion of OTTI losses recognized in other comprehensive income (OCI)	0	1	0	1
Net OTTI losses recognized in income	0	(13)	0	(26)
Net realized gains (losses) excluding OTTI losses	0	(210)	0	(294)
Net Realized Gains Losses	30	(223)	(928)	(320)
Total revenues	8,985	8,527	16,682	16,403
Expenses
Losses and loss expenses	6,577	4,715	11,062	8,813
Policy benefits	223	161	352	357
Policy acquisition costs	1,593	1,544	3,208	3,008
Administrative expenses	727	758	1,468	1,468
Interest expense	128	140	260	280
Other (income) expense	58	(230)	113	(269)
Amortization of purchased intangibles	72	77	145	153
Chubb integration expenses	0	4	0	7
Total expenses	9,378	7,169	16,608	13,817
Income (loss) before income tax	(393)	1,358	74	2,586
Income tax expense (benefit) (includes $(2), $4, $(42), and $(2) on reclassified unrealized gains and losses)	(62)	208	153	396
Net income (loss)	(331)	1,150	(79)	2,190
Other comprehensive income
Unrealized appreciation (depreciation)	3,248	1,252	769	3,097
Reclassification adjustment for net realized (gains) losses included in net income (loss)	33	(12)	352	32
Unrealized appreciation (Depreciation) after reclassification adjustment	3,281	1,240	1,121	3,129
Change in:
Cumulative foreign currency translation adjustment	445	(97)	(414)	50
Postretirement benefit liability adjustment	(22)	(18)	(36)	(45)
Other comprehensive income, before income tax	3,704	1,125	671	3,134
Income tax (expense) benefit related to OCI items	(513)	(216)	(192)	(547)
Other comprehensive income	3,191	909	479	2,587
Comprehensive income	$ 2,860	$ 2,059	$ 400	$ 4,777
Earnings per share
Basic earnings (loss) per share	$ (0.73)	$ 2.52	$ (0.17)	$ 4.78
Diluted earnings (loss) per share	$ (0.73)	$ 2.50	$ (0.17)	$ 4.75
Total net realized gains (losses) reclassified from AOCI	$ (33)	$ 12	$ (352)	$ (32)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	(2)	4	(42)	(2)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Earnings per share
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	$ (2)	$ 4	$ (42)	$ (2)

Consolidated Statements Of Shar

Consolidated Statements Of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Common shares in treasury [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]	Cumulative Foreign Currency Translation Adjustment [Member]	Postretirement Benefit Liability Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance - beginning of period at Dec. 31, 2018		$ 11,121	$ (2,618)	$ 12,557	$ 31,688	$ (545)	$ (1,976)	$ 73
Balance - beginning of period (Previous Accounting Guidance [Member]) at Dec. 31, 2018					31,700
Balance - beginning of period (Accounting Standards Update 2016-13 [Member]) at Dec. 31, 2018					(12)
Common Shares repurchased			(743)
Net shares redeemed under employee share-based compensation plans			268	(190)
Exercise of stock options				(48)
Share-based compensation expense				117
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings				(679)
Net income (loss)	$ 2,190				2,190
Funding of dividends declared from Additional paid-in capital					679
Dividends declared on Common Shares					(679)
Change in period, before reclassification from AOCI, net of income tax expense of $(522), $(225), $(198) and $(549)						2,548
Amounts reclassified from AOCI, net of income tax (expense) benefit of $(2), $4, $(42) and $(2)						30
Change in period, net of income tax expense of $(524), $(221), $(240) and $(551)						2,578
Change in period, net of income tax (expense) benefit of $6, $2, $40 and $(5)							45
Change in period, net of income tax benefit of $5, $3, $8 and $9								(36)
Balance - end of period at Jun. 30, 2019	53,802	11,121	(3,093)	11,757	33,878	2,033	(1,931)	37	$ 139
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax						(549)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	(2)					(2)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax						(551)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax							(5)
Pension liability adjustment, Change in period, income tax (expense) benefit								9
Balance - beginning of period at Mar. 31, 2019		11,121	(2,775)	12,051	32,728	1,014	(1,836)	52
Balance - beginning of period (Previous Accounting Guidance [Member]) at Mar. 31, 2019					32,728
Balance - beginning of period (Accounting Standards Update 2017-08 [Member]) at Mar. 31, 2019					0
Common Shares repurchased			(376)
Net shares redeemed under employee share-based compensation plans			58	1
Exercise of stock options				(14)
Share-based compensation expense				63
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings				(344)
Net income (loss)	1,150				1,150
Funding of dividends declared from Additional paid-in capital					344
Dividends declared on Common Shares					(344)
Change in period, before reclassification from AOCI, net of income tax expense of $(522), $(225), $(198) and $(549)						1,027
Amounts reclassified from AOCI, net of income tax (expense) benefit of $(2), $4, $(42) and $(2)						(8)
Change in period, net of income tax expense of $(524), $(221), $(240) and $(551)						1,019
Change in period, net of income tax (expense) benefit of $6, $2, $40 and $(5)							(95)
Change in period, net of income tax benefit of $5, $3, $8 and $9								(15)
Balance - end of period at Jun. 30, 2019	53,802	11,121	(3,093)	11,757	33,878	2,033	(1,931)	37	139
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax						(225)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	4					4
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax						(221)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax							2
Pension liability adjustment, Change in period, income tax (expense) benefit								3
Balance - beginning of period at Dec. 31, 2019	55,331	11,121	(3,754)	11,203	36,070	2,543	(1,939)	15
Balance - beginning of period (Previous Accounting Guidance [Member]) at Dec. 31, 2019					36,142
Balance - beginning of period (Accounting Standards Update 2016-13 [Member]) at Dec. 31, 2019					(72)
Common Shares repurchased			(326)
Net shares redeemed under employee share-based compensation plans			214	(189)
Exercise of stock options				(29)
Share-based compensation expense				124
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings				(693)
Net income (loss)	(79)				(79)
Funding of dividends declared from Additional paid-in capital					693
Dividends declared on Common Shares					(693)
Change in period, before reclassification from AOCI, net of income tax expense of $(522), $(225), $(198) and $(549)						571
Amounts reclassified from AOCI, net of income tax (expense) benefit of $(2), $4, $(42) and $(2)						310
Change in period, net of income tax expense of $(524), $(221), $(240) and $(551)						881
Change in period, net of income tax (expense) benefit of $6, $2, $40 and $(5)							(374)
Change in period, net of income tax benefit of $5, $3, $8 and $9								(28)
Balance - end of period at Jun. 30, 2020	54,760	11,121	(3,866)	10,416	35,991	3,424	(2,313)	(13)	1,098
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax						(198)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	(42)					(42)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax						(240)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax							40
Pension liability adjustment, Change in period, income tax (expense) benefit								8
Balance - beginning of period at Mar. 31, 2020		11,121	(3,872)	10,710	36,322	667	(2,764)	4
Balance - beginning of period (Previous Accounting Guidance [Member]) at Mar. 31, 2020					36,322
Balance - beginning of period (Accounting Standards Update 2016-13 [Member]) at Mar. 31, 2020					0
Common Shares repurchased			0
Net shares redeemed under employee share-based compensation plans			6	7
Exercise of stock options				(3)
Share-based compensation expense				55
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings				(353)
Net income (loss)	(331)				(331)
Funding of dividends declared from Additional paid-in capital					353
Dividends declared on Common Shares					(353)
Change in period, before reclassification from AOCI, net of income tax expense of $(522), $(225), $(198) and $(549)						2,726
Amounts reclassified from AOCI, net of income tax (expense) benefit of $(2), $4, $(42) and $(2)						31
Change in period, net of income tax expense of $(524), $(221), $(240) and $(551)						2,757
Change in period, net of income tax (expense) benefit of $6, $2, $40 and $(5)							451
Change in period, net of income tax benefit of $5, $3, $8 and $9								(17)
Balance - end of period at Jun. 30, 2020	54,760	$ 11,121	$ (3,866)	$ 10,416	$ 35,991	3,424	(2,313)	(13)	$ 1,098
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax						(522)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	$ (2)					(2)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax						$ (524)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax							$ 6
Pension liability adjustment, Change in period, income tax (expense) benefit								$ 5

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020		Jun. 30, 2019
Cash flows from operating activities
Net income	$ (79)		$ 2,190
Adjustments to reconcile net income to net cash flows from operating activities
Net realized (gains) losses	928		320
Amortization of premiums/discounts on fixed maturities	192		209
Amortization of purchased intangibles	145		153
Deferred income taxes	(302)		(133)
Unpaid losses and loss expenses	3,172		240
Unearned premiums	538		808
Future policy benefits	87		101
Insurance and reinsurance balances payable	118		(94)
Accounts payable, accrued expenses, and other liabilities	(304)		(357)
Income taxes payable	2		16
Insurance and reinsurance balances receivable	(645)		(843)
Reinsurance recoverable	(71)		565
Deferred policy acquisition costs	(62)		(194)
Other	(22)		(273)
Net cash flows from operating activities	3,697		2,708
Cash flows from investing activities
Purchases of fixed maturities available for sale	(13,058)		(12,566)
Purchases of fixed maturities held to maturity	(42)		(73)
Purchases of equity securities	(2,824)		(147)
Sales of fixed maturities available for sale	7,734		7,832
Sales of to be announced mortgage-backed securities	0		6
Sales of equity securities	1,353		266
Maturities and redemptions of fixed maturities available for sale	5,220		3,963
Maturities and redemptions of fixed maturities held to maturity	642		598
Net change in short-term investments	173		(763)
Net derivative instruments settlements	(18)		(536)
Private equity contribution	(546)		(920)
Private equity distribution	443		780
Payments for Other Deposits	(1,550)		0
Other	(221)		(727)
Net cash flows used for investing activities	(2,694)		(2,287)
Cash flows from financing activities
Dividends paid on Common Shares	(678)		(671)
Common Shares repurchased	(333)		(741)
Proceeds from issuance of repurchase agreements	1,402		1,984
Repayment of repurchase agreements	(1,402)		(1,986)
Proceeds from share-based compensation plans	74		95
Policyholder contract deposits	215		237
Policyholder contract withdrawals	(173)		(138)
Proceeds from (Payments for) Other Financing Activities	(3)		0
Net cash flows used for financing activities	(898)		(431)
Proceeds from Issuance of Long-term Debt	0		1,289
Repayments of Long-term Debt	0		(500)
Effect of foreign currency rate changes on cash and restricted cash	(42)		38
Net increase (decrease) in cash and restricted cash	63		28
Cash and restricted cash - beginning of period	1,646	[1]	1,340	[2]
Cash and restricted cash - end of period	1,709	[1]	1,368	[2]
Supplemental cash flow information
Taxes paid	442		522
Interest paid	$ 286		$ 286
[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020 and December 31, 2019, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2019 and December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

General

General	6 Months Ended
	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	General a) Basis of presentation Chubb Limited is a holding company incorporated in Zurich, Switzerland. Chubb Limited, through its subsidiaries, provides a broad range of insurance and reinsurance products to insureds worldwide. 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 2019 Form 10-K. b) 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: June 30 December 31 (in millions of U.S. dollars) 2020 2019 Cash $ 1,557 $ 1,537 Restricted cash 152 109 Total cash and restricted cash shown in the Consolidated statements of cash flows $ 1,709 $ 1,646 c) Goodwill During the six months ended June 30, 2020, Goodwill decreased $112 million, primarily reflecting the impact of foreign exchange. d) Accounting guidance adopted in 2020 Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments Effective January 1, 2020, we adopted, on a modified retrospective basis, new guidance on the accounting for credit losses of financial instruments that are measured at amortized cost, including held to maturity securities, and reinsurance recoverables, by applying an approach based on the current expected credit losses (CECL). The estimate of expected credit losses considers historical information, current information, as well as reasonable and supportable forecasts, including estimates of prepayments. In addition, the guidance also replaced the current available for sale (AFS) security other-than-temporary impairment model by requiring an estimate of the expected credit loss (ECL) only when the fair value is below the amortized cost of the asset. The length of time the fair value of an AFS security has been below its amortized cost no longer impacts the determination of whether a potential credit loss exists. The AFS security model also requires the use of a valuation allowance as compared to the previous practice of writing down the asset. In 2020, we recognized a cumulative effect adjustment and decreased beginning retained earnings by $79 million pre-tax, or $72 million after-tax, principally related to the valuation allowance for credit losses. We also adopted the required disclosures within Note 3 Investments and Note 5 Reinsurance. Results for reporting periods prior to January 1, 2020 are presented in accordance with the previous guidance. Accounting guidance not yet adopted Effects of Reference Rate Reform on Financial Reporting In March 2020, the FASB issued guidance which provides optional expedients and exceptions for applying GAAP to investments, derivatives, or other transactions that reference the London Interbank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of reference rate reform. Along with the optional expedients, the amendments include a general principle that permits an entity to consider contract modifications due to reference reform to be an event that does not require contract re-measurement at the modification date or reassessment of a previous accounting determination. Additionally, a company may make a one-time election to sell, transfer, or both sell and transfer debt securities classified as held to maturity that reference a rate affected by reference rate reform and that were classified as held to maturity before January 1, 2020. This standard may be elected over time through December 31, 2022 as reference rate reform activities occur. We are currently assessing the effect of adopting this guidance on our financial condition and results of operations. 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 2022 with early adoption permitted. However, in July 2020, the FASB proposed to defer the adoption date by one year, therefore, if the guidance is amended, this standard will be effective for us in the first quarter of 2023. 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. Refer to the 2019 Form 10-K for information on additional accounting guidance not yet adopted.

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2020
Business Combinations [Abstract]
Acquisitions	Acquisitions Huatai Group Chubb maintains a direct investment in Huatai Insurance Group Company Limited (Huatai Group). Huatai Group is the parent company of, and owns 100 percent of, Huatai Property & Casualty Insurance Co., Ltd. (Huatai P&C) and approximately 80 percent of Huatai Life Insurance Co., Ltd. (Huatai Life). As of June 30, 2020 Chubb's aggregate ownership interest in Huatai Group was 30.9 percent. Chubb applies the equity method of accounting to its investment in Huatai Group by recording its share of net income or loss in Other (income) expense in the Consolidated statements of operations. In 2019, Chubb entered into agreements to acquire an additional 22.4 percent ownership in Huatai Group for approximately $1.55 billion through two separate purchases, a 15.3 percent ownership interest for approximately $1.1 billion and a 7.1 percent ownership interest for approximately $493 million. On July 13, 2020, we acquired the 15.3 percent ownership interest. The purchase of the additional 7.1 percent ownership interest is contingent upon important conditions that are expected to be completed by the end of 2021. In connection with these purchase agreements, in January 2020, we paid collateralized deposits totaling $1.55 billion to the selling shareholders. This transaction was recorded to Other assets on the Consolidated balance sheet and within investing activities on the Consolidated statement of cash flows.

Investments

Investments	6 Months Ended
	Jun. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Investments	Investments a) Fixed maturities Effective January 1, 2020, we adopted new accounting guidance that requires a valuation allowance for credit losses to be established for fixed maturity securities classified as held to maturity (HTM) or available for sale (AFS). For information on accounting policies applicable to periods prior to January 1, 2020, refer to the 2019 Form 10-K. June 30, 2020 Amortized Valuation Allowance Gross Gross Fair (in millions of U.S. dollars) Available for sale U.S. Treasury / Agency $ 2,636 $ — $ 239 $ — $ 2,875 Non-U.S. 23,370 (17) 1,420 (166) 24,607 Corporate and asset-backed securities 32,721 (52) 1,658 (410) 33,917 Mortgage-backed securities 17,165 — 1,051 (18) 18,198 Municipal 6,848 — 270 (3) 7,115 $ 82,740 $ (69) $ 4,638 $ (597) $ 86,712 Amortized Valuation Allowance Net Carrying Value Gross Gross Fair Held to maturity U.S. Treasury / Agency $ 1,242 $ — $ 1,242 $ 73 $ — $ 1,315 Non-U.S. 1,278 (8) 1,270 102 (2) 1,370 Corporate and asset-backed securities 2,232 (41) 2,191 247 (10) 2,428 Mortgage-backed securities 2,189 (1) 2,188 146 (3) 2,331 Municipal 4,955 (1) 4,954 223 (1) 5,176 $ 11,896 $ (51) $ 11,845 $ 791 $ (16) $ 12,620 December 31, 2019 Amortized Gross Gross Fair OTTI Recognized (in millions of U.S. dollars) Available for sale U.S. Treasury / Agency $ 3,188 $ 96 $ (1) $ 3,283 $ — Non-U.S. 22,670 1,099 (62) 23,707 (25) Corporate and asset-backed securities 30,689 1,180 (78) 31,791 (5) Mortgage-backed securities 18,712 494 (14) 19,192 — Municipal 7,321 205 (11) 7,515 — $ 82,580 $ 3,074 $ (166) $ 85,488 $ (30) Held to maturity U.S. Treasury / Agency $ 1,318 $ 29 $ — $ 1,347 $ — Non-U.S. 1,423 62 — 1,485 — Corporate and asset-backed securities 2,349 121 (2) 2,468 — Mortgage-backed securities 2,331 65 — 2,396 — Municipal 5,160 150 (1) 5,309 — $ 12,581 $ 427 $ (3) $ 13,005 $ — Management evaluates CECL for all HTM securities each quarter. U.S. Treasury and agency securities and U.S. government agency mortgage-backed securities are assumed to have no risk of non-payment and therefore are excluded from the CECL evaluation. The remaining HTM securities are evaluated for potential credit loss on a collective pool basis. We elected to pool HTM securities by 1) external credit rating and 2) time to maturity (duration). These characteristics are the most representative of similar risk characteristics within our portfolio. Chubb will pool HTM securities and calculate an expected credit loss for each pool using Moody’s corporate bond default average, corporate bond recovery rate, and an economic cycle multiplier. The multiplier is based on the leading economic index and will adjust the average default frequency for a forward-looking economic outlook. Prior to the adoption of this guidance, HTM securities were evaluated individually for other-than-temporary impairment (OTTI). Management monitors the credit quality of HTM securities through the review of external credit ratings on a quarterly basis. The following table presents the amortized cost of our HTM securities according to S&P rating: June 30, 2020 (in millions of U.S. dollars) Amortized cost % of Total AAA $ 2,583 22 % AA 6,397 54 % A 2,302 19 % BBB 591 5 % BB 21 — % Other 2 — % Total $ 11,896 100 % Management evaluates expected credit losses (ECL) for AFS securities when fair value is below amortized cost. AFS securities are evaluated for potential credit loss on an individual security level but the evaluation may use assumptions consistent with expectations of credit losses for a group of similar securities. If management has the intent to sell or will be required to sell the security before recovery, the entire impairment loss will be recorded through income to net realized gains and losses. If management does not have the intent to sell or will not be required to sell the security before recovery, an allowance for credit losses is established and the portion of loss that relates to credit losses is recorded in income to Net realized gains (losses) and the portion of loss that relates to non-credit loss is recorded in Other comprehensive income. Examples of criteria that are collectively evaluated to determine if a credit loss has occurred include the following: • The extent to which the fair value is less than amortized cost; • Adverse conditions related to the security, industry, or geographic area; • Downgrades in the security's credit rating by a rating agency; and • Failure of the issuer to make scheduled principal or interest payments AFS securities that meet any one of the criteria included above will be subject to a discounted cash flow analysis by comparing the present value of expected future cash flows with the amortized cost basis. If the present value of expected future cash flows is less than the amortized cost, a credit loss exists and an allowance for credit losses will be recognized. If the present value of expected future cash flows is equal to or greater than the amortized cost basis, management will conclude an expected credit loss does not exist. We elected to not measure an allowance for accrued investment income as uncollectible balances are written off in a timely manner, typically 30 to 45 days after uncollected balances are due. The following table presents fixed maturities by contractual maturity: June 30 December 31 2020 2019 (in millions of U.S. dollars) Net Carrying Value Fair Value Amortized Cost Fair Value Available for sale Due in 1 year or less $ 4,487 $ 4,487 $ 3,951 $ 3,973 Due after 1 year through 5 years 26,867 26,867 27,142 27,720 Due after 5 years through 10 years 25,465 25,465 23,901 24,874 Due after 10 years 11,695 11,695 8,874 9,729 68,514 68,514 63,868 66,296 Mortgage-backed securities 18,198 18,198 18,712 19,192 $ 86,712 $ 86,712 $ 82,580 $ 85,488 Held to maturity Due in 1 year or less $ 890 $ 902 $ 478 $ 479 Due after 1 year through 5 years 3,505 3,662 3,869 3,940 Due after 5 years through 10 years 3,328 3,516 3,756 3,883 Due after 10 years 1,934 2,209 2,147 2,307 9,657 10,289 10,250 10,609 Mortgage-backed securities 2,188 2,331 2,331 2,396 $ 11,845 $ 12,620 $ 12,581 $ 13,005 Expected maturities could differ from contractual maturities because borrowers may have the right to call or prepay obligations, with or without call or prepayment penalties. b) Gross unrealized loss Fixed maturities in an unrealized loss position at June 30, 2020 comprised both investment grade and below investment grade securities for which fair value declined primarily due to widening credit spreads since the date of purchase. The following table presents, for AFS fixed maturities in an unrealized loss position (including securities on loan) that are not deemed to have credit losses, the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position: 0 – 12 Months Over 12 Months Total June 30, 2020 Fair Value Gross Fair Value Gross Fair Value Gross (in millions of U.S. dollars) Non-U.S. $ 3,172 $ (117) $ 105 $ (22) $ 3,277 $ (139) Corporate and asset-backed securities 7,985 (295) 551 (35) 8,536 (330) Mortgage-backed securities 953 (13) 27 (2) 980 (15) Municipal 95 (1) 65 (2) 160 (3) Total AFS fixed maturities $ 12,205 $ (426) $ 748 $ (61) $ 12,953 $ (487) The following table presents, for all securities in an unrealized loss position (including securities on loan), the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position: 0 – 12 Months Over 12 Months Total December 31, 2019 Fair Value Gross Fair Value Gross Fair Value Gross (in millions of U.S. dollars) U.S. Treasury / Agency $ 234 $ (1) $ 339 $ — $ 573 $ (1) Non-U.S. 1,846 (34) 802 (28) 2,648 (62) Corporate and asset-backed securities 2,121 (40) 988 (40) 3,109 (80) Mortgage-backed securities 1,174 (6) 932 (8) 2,106 (14) Municipal 188 — 276 (12) 464 (12) Total fixed maturities $ 5,563 $ (81) $ 3,337 $ (88) $ 8,900 $ (169) c) Net realized gains (losses) Management reviews credit losses and the valuation allowance for expected credit losses each quarter. When all or a portion of a fixed maturity security is identified to be uncollectible and written off, the valuation allowance for expected credit losses is reduced by the same amount. In general, a security is considered uncollectible no later than when all efforts to collect contractual cash flows have been exhausted. Below are considerations for when a security may be deemed uncollectible: • We have sufficient information to determine that the issuer of the security is insolvent; • We receive notice that the issuer of the security has filed for bankruptcy, and the collectability is expected to be adversely impacted by the bankruptcy; • The issuer of a security has violated multiple debt covenants; • Amounts have been past due for a specified period of time with no response from the issuer; • A significant deterioration in the value of the collateral has occurred; • We have received correspondence from the issuer of the security indicating that it doesn’t intend to pay the contractual principal and interest. Projected cash flows are driven primarily by assumptions regarding probability of default and also the timing and amount of recoveries associated with defaults. Chubb developed the projected cash flows using market data, issuer-specific information, and credit ratings. In combination with contractual cash flows and the use of historical default and recovery data by Moody’s Investors Service (Moody’s) rating category we generate expected cash flows using the average cumulative issuer-weighted global default rates by letter rating. The following table presents the components of Net realized gains (losses): Three Months Ended Six Months Ended June 30 June 30 (in millions of U.S. dollars) 2020 2019 2020 2019 Fixed maturities: OTTI on fixed maturities, gross $ — $ (14) $ — $ (27) OTTI on fixed maturities recognized in OCI (pre-tax) — 1 — 1 OTTI on fixed maturities, net — (13) — (26) Gross realized gains excluding OTTI 68 56 145 83 Gross realized losses excluding OTTI (174) (31) (299) (89) Provision for expected credit losses 104 — (46) — Impairment (1) (31) — (152) — Total fixed maturities $ (33) $ 12 $ (352) $ (32) Equity securities 148 5 119 63 Other investments (107) 30 (102) (14) Foreign exchange gains (losses) (61) (11) (129) 2 Investment and embedded derivative instruments 14 (181) 29 (311) Fair value adjustments on insurance derivative 213 (65) (472) 49 S&P futures (103) (20) 22 (83) Other derivative instruments (1) 7 (3) 6 Other (40) — (40) — Net realized gains (losses) (pre-tax) $ 30 $ (223) $ (928) $ (320) (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 June 30 2020 2019 (in millions of U.S. dollars) Equity Securities Other Investments Total Equity Securities Other Investments Total Net gains (losses) recognized during the period $ 148 $ (107) $ 41 $ 5 $ 30 $ 35 Less: Net gains (losses) recognized from sales of securities 187 — 187 32 — 32 Unrealized gains (losses) recognized for securities still held at reporting date $ (39) $ (107) $ (146) $ (27) $ 30 $ 3 Six Months Ended June 30 2020 2019 (in millions of U.S. dollars) Equity Securities Other Investments Total Equity Securities Other Investments Total Net gains (losses) recognized during the period $ 119 $ (102) $ 17 $ 63 $ (14) $ 49 Less: Net gains (losses) recognized from sales of securities 163 — 163 33 (2) 31 Unrealized gains (losses) recognized for securities still held at reporting date $ (44) $ (102) $ (146) $ 30 $ (12) $ 18 The following table presents a roll-forward of valuation allowance for expected credit losses on fixed maturities: Three Months Ended Six Months Ended June 30 June 30 (in millions of U.S. dollars) 2020 2020 Available for sale Valuation allowance for expected credit losses - beginning of period $ 176 $ — Impact of adoption of new accounting guidance — 25 Provision for expected credit loss 29 178 Initial allowance for purchased securities with credit deterioration 3 5 Write-offs charged against the expected credit loss (5) (5) Recovery of expected credit loss (134) (134) Valuation allowance for expected credit losses - end of period $ 69 $ 69 Held to maturity Valuation allowance for expected credit losses - beginning of period $ 45 $ — Impact of adoption of new accounting guidance — 44 Provision for expected credit loss 6 7 Valuation allowance for expected credit losses - end of period $ 51 $ 51 Purchased Credit Deterioration (PCD) Securities During the six months ended June 30, 2020, we purchased $107 million of securities with credit deterioration, categorized as available for sale, and assessed an allowance for credit losses of $5 million at acquisition. These PCD securities had a par value at acquisition of $143 million. Alternative investments Alternative investments include partially-owned investment companies, investment funds, and limited partnerships measured at fair value using their respective net asset values or equivalent (NAV) as a practical expedient. The following table presents, by investment category, the expected liquidation period, fair value, and maximum future funding commitments of alternative investments: June 30 December 31 Expected 2020 2019 (in millions of U.S. dollars) Fair Maximum Fair Maximum Financial 2 to 10 Years $ 521 $ 309 $ 611 $ 329 Real Assets 2 to 11 Years 674 749 712 422 Distressed 2 to 8 Years 220 158 263 80 Private Credit 3 to 8 Years 81 272 104 272 Traditional 2 to 14 Years 3,039 1,852 2,844 2,160 Vintage 1 to 2 Years 90 — 116 — Investment funds Not Applicable 228 — 271 — $ 4,853 $ 3,340 $ 4,921 $ 3,263 Included in all categories in the above table, except for Investment funds, are investments for which Chubb will never have the contractual option to redeem but receives distributions based on the liquidation of the underlying assets. Further, for all categories except for Investment funds, Chubb does not have the ability to sell or transfer the investments without the consent from the general partner of individual funds. Investment Category: Consists of investments in private equity funds: Financial targeting financial services companies, such as financial institutions and insurance services worldwide Real Assets targeting investments related to hard, physical assets, such as real estate, infrastructure and natural resources Distressed targeting distressed corporate debt/credit and equity opportunities in the U.S. Private Credit targeting privately originated corporate debt investments, including senior secured loans and subordinated bonds Traditional employing traditional private equity investment strategies, such as buyout and growth equity globally Vintage funds where the initial fund term has expired Investment funds employ various investment strategies, such as long/short equity and arbitrage/distressed. Included in this category are investments for which Chubb has the option to redeem at agreed upon value as described in each investment fund’s subscription agreement. Depending on the terms of the various subscription agreements, investment fund investments may be redeemed monthly, quarterly, semi-annually, or annually. If Chubb wishes to redeem an investment fund investment, it must first determine if the investment fund is still in a lock-up period (a time when Chubb cannot redeem its investment so that the investment fund manager has time to build the portfolio). If the investment fund is no longer in its lock-up period, Chubb must then notify the investment fund manager of its intention to redeem by the notification date prescribed by the subscription agreement. Subsequent to notification, the investment fund can redeem Chubb’s investment within several months of the notification. Notice periods for redemption of the investment funds range up to 270 days. Chubb can redeem its investment funds without consent from the investment fund managers. d) 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 June 30, 2020 and December 31, 2019 are investments, primarily fixed maturities, totaling $19.6 billion and $21.0 billion, respectively, and cash of $152 million and $109 million, respectively. The following table presents the components of restricted assets: June 30 December 31 (in millions of U.S. dollars) 2020 2019 Trust funds $ 12,522 $ 14,004 Deposits with U.S. regulatory authorities 2,424 2,466 Deposits with non-U.S. regulatory authorities 2,807 2,709 Assets pledged under repurchase agreements 1,460 1,464 Other pledged assets 523 490 Total $ 19,736 $ 21,133

Fair value measurements

Fair value measurements	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair value measurements	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, which include available relevant market information, benchmark curves, benchmarking of like securities, sector groupings, and matrix pricing. Additional valuation factors that can be taken into account are nominal spreads, dollar basis, and liquidity adjustments. The pricing services evaluate each asset class based on relevant market and credit information, perceived market movements, and sector news. The market inputs used in the pricing evaluation, listed in the approximate order of priority include: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, reference data, and industry and economic events. The extent of the use of each input is dependent on the asset class and the market conditions. Given the asset class, the priority of the use of inputs may change, or some market inputs may not be relevant. Additionally, fixed maturities valuation is more subjective when markets are less liquid due to the lack of market based inputs (i.e., stale pricing), which may increase the potential that an investment's estimated fair value is not reflective of the price at which an actual transaction would occur. The overwhelming majority of fixed maturities are classified within Level 2 because the most significant inputs used in the pricing techniques are observable. For a small number of fixed maturities, we obtain a single broker quote (typically from a market maker). Due to the disclaimers on the quotes that indicate that the price is indicative only, we include these fair value estimates in Level 3. Equity securities Equity securities with active markets are classified within Level 1 as fair values are based on quoted market prices. For equity securities in markets which are less active, fair values are based on market valuations and are classified within Level 2. Equity securities for which pricing is unobservable are classified within Level 3. Short-term investments Short-term investments, which comprise securities due to mature within one year of the date of purchase that are traded in active markets, are classified within Level 1 as fair values are based on quoted market prices. Securities such as commercial paper and discount notes are classified within Level 2 because these securities are typically not actively traded due to their approaching maturity and, as such, their cost approximates fair value. Short-term investments for which pricing is unobservable are classified within Level 3. Other investments Fair values for the majority of Other investments including investments in partially-owned investment companies, investment funds, and limited partnerships are based on their respective net asset values or equivalent (NAV) and are excluded from the fair value hierarchy table below. Certain of our long-duration contracts are supported by assets that do not qualify for separate account reporting under GAAP. These assets comprise mutual funds classified within Level 1 in the valuation hierarchy on the same basis as other equity securities traded in active markets. Other investments also include equity securities classified within Level 1, and fixed maturities, classified within Level 2, held in rabbi trusts maintained by Chubb for deferred compensation plans and 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 reserves for our guaranteed minimum death benefits (GMDB) and 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 and Future policy benefits in the Consolidated balance sheets. For GLB reinsurance, Chubb estimates fair value using an internal valuation model which includes current market information and estimates of policyholder behavior. All of the treaties contain claim limits, which are factored into the valuation model. The fair value depends on a number of factors, including interest rates, equity markets, credit risk, current account value, market volatility, expected annuitization rates and other policyholder behavior, and changes in policyholder mortality. 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 June 30, 2020 Level 1 Level 2 Level 3 Total (in millions of U.S. dollars) Assets: Fixed maturities available for sale U.S. Treasury / Agency $ 2,316 $ 559 $ — $ 2,875 Non-U.S. — 24,138 469 24,607 Corporate and asset-backed securities — 32,548 1,369 33,917 Mortgage-backed securities — 18,138 60 18,198 Municipal — 7,115 — 7,115 2,316 82,498 1,898 86,712 Equity securities 2,329 1 64 2,394 Short-term investments 2,707 1,294 2 4,003 Other investments (1) 361 383 10 754 Securities lending collateral — 1,832 — 1,832 Investment derivative instruments 19 — — 19 Other derivative instruments 1 — — 1 Separate account assets 3,394 132 — 3,526 Total assets measured at fair value (1) $ 11,127 $ 86,140 $ 1,974 $ 99,241 Liabilities: Investment derivative instruments $ 96 $ — $ — $ 96 GLB (2) — — 928 928 Total liabilities measured at fair value $ 96 $ — $ 928 $ 1,024 (1) Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,853 million, policy loans of $226 million and other investments of $90 million at June 30, 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. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. December 31, 2019 Level 1 Level 2 Level 3 Total (in millions of U.S. dollars) Assets: Fixed maturities available for sale U.S. Treasury / Agency $ 2,664 $ 619 $ — $ 3,283 Non-U.S. — 23,258 449 23,707 Corporate and asset-backed securities — 30,340 1,451 31,791 Mortgage-backed securities — 19,132 60 19,192 Municipal — 7,515 — 7,515 2,664 80,864 1,960 85,488 Equity securities 728 15 69 812 Short-term investments 2,803 1,482 6 4,291 Other investments (1) 412 377 10 799 Securities lending collateral — 994 — 994 Investment derivative instruments 24 — — 24 Other derivative instruments 2 — — 2 Separate account assets 3,437 136 — 3,573 Total assets measured at fair value (1) $ 10,070 $ 83,868 $ 2,045 $ 95,983 Liabilities: Investment derivative instruments $ 93 $ — $ — $ 93 Other derivative instruments 13 — — 13 GLB (2) — — 456 456 Total liabilities measured at fair value $ 106 $ — $ 456 $ 562 (1) Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,921 million and other investments of $95 million at December 31, 2019 measured using NAV as a practical expedient. (2) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. 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 Significant Ranges Weighted Average (1) June 30, 2020 December 31, 2019 GLB (1) $ 928 $ 456 Actuarial model Lapse rate 3% – 34% 4.6 % Annuitization rate 0% – 52% 4.1 % (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 and six months ended June 30, 2020 and 2019, 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 2019 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 Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 465 $ 1,502 $ 60 $ 67 $ 1 $ 10 $ 1,141 Transfers out of Level 3 (13) (71) — — — — — Change in Net Unrealized Gains (Losses) in OCI (6) 1 — (1) — — — Net Realized Gains/Losses (1) (13) — (1) — — (213) Purchases 67 83 — 8 1 — — Sales (16) (48) — (9) — — — Settlements (27) (85) — — — — — Balance – end of period $ 469 $ 1,369 $ 60 $ 64 $ 2 $ 10 $ 928 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ 5 $ — $ 1 $ — $ — $ (213) Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date $ (5) $ 7 $ — $ — $ — $ — $ — (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $1,372 million at June 30, 2020, and $1,591 million at March 31, 2020, which includes a fair value derivative adjustment of $928 million and $1,141 million, respectively. Assets Liabilities Three Months Ended Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 360 $ 1,342 $ 78 $ 55 $ — $ 11 $ 338 Transfers into Level 3 — 10 — — — — — Change in Net Unrealized Gains/Losses in OCI, including foreign exchange — 1 — 1 — — — Net Realized Gains/Losses — (1) — (1) — — 65 Purchases 43 121 — 5 4 — — Sales (14) (36) (1) (4) — — — Settlements (18) (78) (1) — — — — Balance – end of period $ 371 $ 1,359 $ 76 $ 56 $ 4 $ 11 $ 403 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ (1) $ — $ (1) $ — $ — $ 65 (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $815 million at June 30, 2019, and $741 million at March 31, 2019, which includes a fair value derivative adjustment of $403 million and $338 million, respectively. Assets Liabilities Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Six Months Ended Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 449 $ 1,451 $ 60 $ 69 $ 6 $ 10 $ 456 Transfers into Level 3 — 91 — — — — — Transfers out of Level 3 (16) (72) — — — — — Change in Net Unrealized Gains (Losses) in OCI, including foreign exchange (20) (44) — — — — — Net Realized Gains/Losses (3) (26) — (3) — — 472 Purchases 149 222 — 11 2 — — Sales (62) (67) — (13) — — — Settlements (28) (186) — — (6) — — Balance – end of period $ 469 $ 1,369 $ 60 $ 64 $ 2 $ 10 $ 928 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ (9) $ — $ (1) $ — $ — $ 472 Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date $ (20) $ (37) $ — $ — $ — $ — $ — (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $1,372 million at June 30, 2020, and $897 million at December 31, 2019, which includes a fair value derivative adjustment of $928 million and $456 million, respectively. Assets Liabilities Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Six Months Ended Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 345 $ 1,299 $ 61 $ 57 $ 1 $ 11 $ 452 Transfers into Level 3 3 15 — — — — — Transfers out of Level 3 (15) — — — — — — Change in Net Unrealized Gains/Losses in OCI, including foreign exchange 6 5 — 2 — — — Net Realized Gains/Losses (1) — — (3) — — (49) Purchases 96 249 18 14 4 — — Sales (19) (73) (1) (14) — — — Settlements (44) (136) (2) — (1) — — Balance – end of period $ 371 $ 1,359 $ 76 $ 56 $ 4 $ 11 $ 403 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ (1) $ — $ (2) $ — $ — $ (49) (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $815 million at June 30, 2019, and $861 million at December 31, 2018, which includes a fair value derivative adjustment of $403 million and $452 million, respectively. b) Financial instruments disclosed, but not measured, at fair value Chubb uses various financial instruments in the normal course of its business. Our insurance contracts are excluded from fair value of financial instruments accounting guidance, and therefore, are not included in the amounts discussed below. The carrying values of cash, other assets, other liabilities, and other financial instruments not included below approximated their fair values. Refer to the 2019 Form 10-K for information on the fair value methods and assumptions for investments in partially-owned insurance companies, short-term and long-term debt, repurchase agreements, and trust-preferred securities. The following tables present fair value, by valuation hierarchy, and carrying value of the financial instruments not measured at fair value: June 30, 2020 Fair Value Net Carrying (in millions of U.S. dollars) Level 1 Level 2 Level 3 Total Assets: Fixed maturities held to maturity U.S. Treasury / Agency $ 1,257 $ 58 $ — $ 1,315 $ 1,242 Non-U.S. — 1,370 — 1,370 1,270 Corporate and asset-backed securities — 2,428 — 2,428 2,191 Mortgage-backed securities — 2,331 — 2,331 2,188 Municipal — 5,176 — 5,176 4,954 Total assets $ 1,257 $ 11,363 $ — $ 12,620 $ 11,845 Liabilities: Repurchase agreements $ — $ 1,409 $ — $ 1,409 $ 1,409 Short-term debt — 1,309 — 1,309 1,300 Long-term debt — 15,650 — 15,650 13,656 Trust preferred securities — 453 — 453 308 Total liabilities $ — $ 18,821 $ — $ 18,821 $ 16,673 December 31, 2019 Fair Value Carrying (in millions of U.S. dollars) Level 1 Level 2 Level 3 Total Assets: Fixed maturities held to maturity U.S. Treasury / Agency $ 1,292 $ 55 $ — $ 1,347 $ 1,318 Non-U.S. — 1,485 — 1,485 1,423 Corporate and asset-backed securities — 2,436 32 2,468 2,349 Mortgage-backed securities — 2,396 — 2,396 2,331 Municipal — 5,309 — 5,309 5,160 Total assets $ 1,292 $ 11,681 $ 32 $ 13,005 $ 12,581 Liabilities: Repurchase agreements $ — $ 1,416 $ — $ 1,416 $ 1,416 Short-term debt — 1,307 — 1,307 1,299 Long-term debt — 15,048 — 15,048 13,559 Trust preferred securities — 467 — 467 308 Total liabilities $ — $ 18,238 $ — $ 18,238 $ 16,582

Reinsurance (Notes)

Reinsurance (Notes)	6 Months Ended
	Jun. 30, 2020
Credit Loss [Abstract]
Reinsurance [Text Block]	Reinsurance Reinsurance recoverable on ceded reinsurance June 30, 2020 December 31, 2019 (in millions of U.S. dollars) Net Reinsurance Recoverable (1) Valuation allowance Net Reinsurance Recoverable (1) Valuation allowance Reinsurance recoverable on unpaid losses and loss expenses $ 14,361 $ 240 $ 14,181 $ 240 Reinsurance recoverable on paid losses and loss expenses 846 63 1,000 76 Reinsurance recoverable on losses and loss expenses $ 15,207 $ 303 $ 15,181 $ 316 Reinsurance recoverable on policy benefits $ 197 $ 4 $ 197 $ 4 (1) Net of valuation allowance for uncollectible reinsurance. We evaluate the financial condition of our reinsurers and potential reinsurers on a regular basis and also monitor concentrations of credit risk with reinsurers. The valuation allowance for uncollectible reinsurance is required principally due to the potential failure of reinsurers to indemnify Chubb, primarily because of disputes under reinsurance contracts and insolvencies. We have established a valuation allowance for amounts estimated to be uncollectible on both unpaid and paid losses as well as future policy benefits. Management evaluates the need for a valuation allowance for uncollectible reinsurance recoverable using current and historical factors, and forecasts each quarter. These factors include a review of active and run-off lines of business, review of reinsurer financial strength ratings, and review of our largest reinsurers. The evaluation of the valuation allowance includes several judgments including certain aspects of the allocation of reinsurance recoverable on incurred but not reported (IBNR) claims by reinsurer and a default analysis to estimate uncollectible reinsurance. The primary components of the default analysis are reinsurance recoverable balances by reinsurer, net of collateral, and default factors used to determine the portion of a reinsurer's balance deemed uncollectible. Default factors require considerable judgment and are determined using principally the current financial strength rating, or rating equivalent, of each reinsurer. Changes in the valuation allowance for uncollectible reinsurance recoverables are recorded in Losses and loss expenses in the Consolidated statements of operations. For additional information, refer to Note 1 d) to the Consolidated Financial Statements of our 2019 Form 10-K. The evaluation of the valuation allowance at December 31, 2019 was consistent with the new accounting guidance adopted January 1, 2020, therefore, there was no material change to the valuation allowance upon adoption. The following table presents a roll-forward of valuation allowance for uncollectible reinsurance related to Reinsurance recoverable on loss and loss expenses: Six Months Ended June 30 (in millions of U.S. dollars) 2020 Reinsurance recoverable Valuation allowance for uncollectible reinsurance - beginning of period $ 316 Provision for uncollectible reinsurance 5 Write-offs charged against the valuation allowance (19) Foreign exchange revaluation 1 Valuation allowance for uncollectible reinsurance - end of period $ 303

Unpaid losses and loss expenses

Unpaid losses and loss expenses	6 Months Ended
	Jun. 30, 2020
Liability for Claims and Claims Adjustment Expense [Abstract]
Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block]	Unpaid losses and loss expenses The following table presents a reconciliation of beginning and ending Unpaid losses and loss expenses: Six Months Ended June 30 (in millions of U.S. dollars) 2020 2019 Gross unpaid losses and loss expenses – beginning of period $ 62,690 $ 62,960 Reinsurance recoverable on unpaid losses - beginning of period (1) (14,181) (14,689) Net unpaid losses and loss expenses – beginning of period 48,509 48,271 Net losses and loss expenses incurred in respect of losses occurring in: Current year 11,111 9,224 Prior years (2) (49) (411) Total 11,062 8,813 Net losses and loss expenses paid in respect of losses occurring in: Current year 2,263 2,288 Prior years 5,842 5,823 Total 8,105 8,111 Foreign currency revaluation and other (128) (1) Net unpaid losses and loss expenses – end of period 51,338 48,972 Reinsurance recoverable on unpaid losses (1) 14,361 14,233 Gross unpaid losses and loss expenses – end of period $ 65,699 $ 63,205 (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 $6 million and $19 million for the six months ended June 30, 2020 and 2019, respectively. Gross and net unpaid losses and loss expenses increased $3,009 million and $2,829 million, respectively, for the six months ended June 30, 2020, driven by catastrophe losses incurred principally related to the COVID-19 pandemic and an increase in underlying reserves, partially offset by favorable foreign exchange movement. 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 June 30 Six Months Ended June 30 (in millions of U.S. dollars) Long-tail Short-tail Total Long-tail Short-tail Total 2020 North America Commercial P&C Insurance $ (141) $ (5) $ (146) $ (184) $ (67) $ (251) North America Personal P&C Insurance — (1) (1) — — — North America Agricultural Insurance — — — — (14) (14) Overseas General Insurance (1) (35) (36) (1) (39) (40) Global Reinsurance (19) 3 (16) (19) (4) (23) Corporate 274 — 274 285 — 285 Total $ 113 $ (38) $ 75 $ 81 $ (124) $ (43) 2019 North America Commercial P&C Insurance $ (206) $ 21 $ (185) $ (271) $ (45) $ (316) North America Personal P&C Insurance — (16) (16) — (26) (26) North America Agricultural Insurance — — — — (61) (61) Overseas General Insurance — (20) (20) — (24) (24) Global Reinsurance (33) 33 — (34) 26 (8) Corporate 33 — 33 43 — 43 Total $ (206) $ 18 $ (188) $ (262) $ (130) $ (392) Significant prior period movements by segment, principally driven by reserve reviews completed during each respective period, are discussed in more detail below. The remaining net development for long-tail lines and short-tail business for each segment and Corporate comprises numerous favorable and adverse movements across a number of lines and accident years, none of which is significant individually or in the aggregate. North America Commercial P&C Insurance 2020 For the three months ended June 30, 2020, net favorable PPD was $146 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 $141 million in long-tail business, primarily from: • Net favorable development of $152 million in our workers’ compensation lines. This included favorable development of $62 million related to our annual assessment of multi-claimant events including industrial accidents, in the 2019 accident year. Consistent with prior years, we reviewed these potential exposures after the close of the accident year to allow for late reporting or identification of significant losses. This development in accident year 2019 was partially offset by some higher than expected activity from other claims. The remaining overall favorable development was mainly in accident years 2015 and prior, driven by lower than expected loss experience and related updates to loss development factors; • Net favorable development of $59 million in general liability portfolios, mainly driven by lower than expected paid and reported loss experience in accident years 2016 and prior, partly offset by some adverse emergence in accident years 2017 through 2019; • Net adverse development of $75 million in commercial automobile liability, mainly in high deductible and excess portfolios, driven by adverse paid and reported loss experience and related updates to loss development factors, mainly in accident years 2015 through 2019; and • Net adverse development of $5 million for U.S. child molestation claims, predominantly reviver statute-related. For the six months ended June 30, 2020, net favorable PPD was $251 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 $184 million in long-tail business, primarily from: • Net favorable development of $182 million in workers’ compensation lines, mainly due to the same factors experienced for the three months ended June 30, 2020, as described above; • Net favorable development of $66 million in professional liability (errors & omissions and cyber), in accident years 2016 and prior, due to lower than expected emergence; • Net favorable development of $43 million in voluntary environmental lines, in accident years 2016 and prior, due to lower than expected emergence and a favorable revision to loss development patterns; • Net favorable development of $36 million in general liability coverages, mainly due to the same factors experienced for the three months ended June 30, 2020, as described above, as well as adverse wholesale general liability results, driven by higher than expected reported loss emergence in accident years 2014 through 2019; • Net adverse development of $75 million in commercial automobile liability, due to the same factors experienced for the three months ended June 30, 2020, as described above; • Net adverse development of $40 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 $5 million for U.S. child molestation claims, predominantly reviver statute-related. • Net favorable development of $67 million in short-tail business, primarily from: • Net favorable development of $37 million, in accident & health, mainly in accident years 2018 and 2019, driven by lower than expected paid loss emergence; and • Net favorable development of $31 million in surety, driven by accident year 2018, where loss emergence was lower than expected. 2019 For the three months ended June 30, 2019, net favorable PPD was $185 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 $206 million in long-tail business, primarily from: • Net favorable development of $163 million in our workers’ compensation lines. This included favorable development of $61 million related to our annual assessment of multi-claimant events including industrial accidents, in the 2018 accident year. Consistent with prior years, we reviewed these potential exposures after the close of the accident year to allow for late reporting or identification of significant losses. This development in accident year 2018 was partially offset by some higher than expected activity from other claims and from involuntary pools. The remaining overall favorable development was mainly in accident years 2014 and prior, driven by lower than expected loss experience and related updates to loss development factors; • Net favorable development of $50 million in our general liability portfolios, mainly driven by lower than expected paid and reported loss experience in accident years 2015 and prior, partly offset by adverse developments in more recent accident years; and • Net adverse development of $25 million in automobile liability, driven by adverse paid and reported loss experience mainly in accident years 2014 through 2018. • Net adverse development of $21 million in short-tail business, which was the result of several adverse movements, in lines such as automobile physical damage and involuntary pools, none of which were significant individually or in the aggregate, mainly impacting accident year 2018. For the six months ended June 30, 2019, net favorable PPD was $316 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 $271 million in long-tail business, primarily from: • Net favorable development of $200 million in our workers’ compensation lines, mainly due to the same factors experienced for the three months ended June 30, 2019, as described above; • Net favorable development of $54 million in professional liability (errors & omissions and cyber), mainly in the 2015 and prior accident years where case activity was less than expected, partially offset by adverse development in the 2016 accident year, which was driven by several large adverse claim developments; • Net favorable development of $31 million in commercial excess and umbrella portfolios, driven by the 2013 and prior accident years, where case emergence was less than expected and greater weight was given to experience-based methods; this was partially offset by higher than expected claim activity in the 2015, 2016, and 2018 accident years which led to reserve strengthening in those years; and • Net adverse development of $31 million in automobile liability, mainly due to the same factors experienced for the three months ended June 30, 2019, as described above. • Net favorable development of $45 million in short-tail business, primarily from favorable development of $49 million in surety business, mainly in the 2017 accident year, driven by lower than expected reported loss activity. North America Agricultural Insurance Prior period development in this segment mainly relates to our Multiple Peril Crop Insurance (MPCI) business and was favorable due to better than expected crop yield results in certain states at the prior year-end period (i.e., 2020 results based on 2019 crop year). Overseas General Insurance For the three and six months ended June 30, 2020, net favorable PPD was $36 million and $40 million, respectively, which was the net result of several underlying favorable and adverse movements, including $19 million and $22 million, respectively, in marine lines across all regions mainly in accident years 2017 and 2018 and favorable case-specific settlements in accident years 2014 and prior. Global Reinsurance For the three and six months ended June 30, 2020, net favorable PPD was $16 million and $23 million, respectively, which was the net result of several underlying favorable and adverse movements, none of which is significant individually or in the aggregate. Corporate 2020 For the three and six months ended June 30, 2020, net adverse development was $274 million and $285 million, respectively, driven by adverse development of $254 million for U.S. child molestation claims, predominantly reviver statute-related. The remainder of the adverse development ($20 million and $31 million, respectively) was driven by increased claim costs on a limited number of non-A&E run-off casualty and workers’ compensation exposures, and charges relating to unallocated loss adjustment expenses due to run-off operating expenses. 2019 For the three and six months ended June 30, 2019, net adverse development was $33 million and $43 million, respectively, from the non A&E run-off casualty exposures, including workers' compensation, driven by increased claim costs and net adverse settlements on a limited number of claims and charges relating to unallocated loss adjustment expenses due to run-off operating expenses.

Commitments, contingencies, and

Commitments, contingencies, and guarantees	6 Months Ended
	Jun. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments, contingencies, and guarantees	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. Benefit reserves in respect of GLBs are classified as Future policy benefits (FPB) while the fair value derivative adjustment is classified within AP. Chubb also generally maintains positions in exchange-traded equity futures contracts on equity market indices to limit equity exposure in the GMDB and GLB 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: June 30, 2020 December 31, 2019 Consolidated Fair Value Notional Fair Value Notional (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) $ 16 $ (85) $ 2,462 $ 11 $ (78) $ 2,579 Options/Futures contracts on notes, bonds, and equities OA / (AP) 3 (11) 1,398 13 (15) 1,615 Convertible securities (1) FM AFS / ES 8 — 10 4 — 5 $ 27 $ (96) $ 3,870 $ 28 $ (93) $ 4,199 Other derivative instruments: Futures contracts on equities (2) OA / (AP) $ — $ — $ 598 $ — $ (13) $ 613 Other OA / (AP) 1 — 97 2 — 63 $ 1 $ — $ 695 $ 2 $ (13) $ 676 GLB (3) (AP) / (FPB) $ — $ (1,372) $ 2,196 $ — $ (897) $ 1,510 (1) Includes fair value of embedded derivatives. (2) Related to GMDB and GLB book of business. (3) Includes both future policy benefits reserves of $444 million and $441 million and fair value derivative adjustment of $928 million and $456 million at June 30, 2020 and December 31, 2019, respectively. Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts. At June 30, 2020 and December 31, 2019, derivative liabilities of $71 million and $75 million, respectively, included in the table above were subject to a master netting agreement. The remaining derivatives included in the table above were not subject to a master netting agreement. The following table presents net realized gains (losses) related to derivative instrument activity in the Consolidated statements of operations: Three Months Ended Six Months Ended June 30 June 30 (in millions of U.S. dollars) 2020 2019 2020 2019 Investment and embedded derivative instruments: Foreign currency forward contracts $ 10 $ (22) $ 53 $ (37) Interest rate swaps — (135) — (215) All other futures contracts, options, and equities 3 (25) (24) (61) Convertible securities (1) 1 1 — 2 Total investment and embedded derivative instruments $ 14 $ (181) $ 29 $ (311) GLB and other derivative instruments: GLB (2) $ 213 $ (65) $ (472) $ 49 Futures contracts on equities (3) (103) (20) 22 (83) Other (1) 7 (3) 6 Total GLB and other derivative instruments $ 109 $ (78) $ (453) $ (28) $ 123 $ (259) $ (424) $ (339) (1) Includes embedded derivatives. (2) Excludes foreign exchange gains (losses) related to GLB. (3) 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 foreign currencies at a future date. Chubb uses forwards to minimize the effect of fluctuating foreign currencies as discussed above. (ii) Duration management and market exposure Futures Futures contracts give the holder the right and obligation to participate in market movements, determined by the index or underlying security on which the futures contract is based. Settlement is made daily in cash by an amount equal to the change in value of the futures contract times a multiplier that scales the size of the contract. Exchange-traded futures contracts on money market instruments, notes, and bonds are used in fixed maturity portfolios to more efficiently manage duration, as substitutes for ownership of the money market instruments, bonds, and notes without significantly increasing the risk in the portfolio. Investments in futures contracts may be made only to the extent that there are assets under management not otherwise committed. Exchange-traded equity futures contracts are used to limit exposure to a severe equity market decline, which would cause an increase in expected claims and therefore, an increase in reserves for GMDB and GLB reinsurance business. Options An option contract conveys to the holder the right, but not the obligation, to purchase or sell a specified amount or value of an underlying security at a fixed price. Option contracts are used in 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. Premiums received under the reinsurance treaties are classified as premium. Expected losses allocated to premiums received are classified as Future policy benefits and valued similar to GMDB reinsurance. Other changes in fair value arise principally from changes in expected losses allocated to expected future premiums. 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 June 30, 2020 December 31, 2019 (in millions of U.S. dollars) Overnight and Continuous Collateral held under securities lending agreements: Cash $ 665 $ 346 U.S. Treasury / Agency 52 6 Non-U.S. 1,059 595 Corporate and asset-backed securities 20 5 Mortgage-backed securities — 18 Equity securities 36 24 $ 1,832 $ 994 Gross amount of recognized liability for securities lending payable $ 1,832 $ 994 At June 30, 2020 and December 31, 2019, our repurchase agreement obligations of $1,409 million and $1,416 million, respectively, were fully collateralized. In contrast to securities lending programs, the use of cash received is not restricted for the repurchase obligations. The fair value of the underlying securities sold remains in Fixed maturities available for sale and the repurchase agreement obligation is recorded in Repurchase agreements in the Consolidated balance sheets. The following table presents the carrying value of collateral pledged under repurchase agreements by investment category and remaining contractual maturity of the underlying agreements: Remaining contractual maturity June 30, 2020 December 31, 2019 Greater than Total Up to 30 Days 30-90 Days Greater than Total (in millions of U.S. dollars) Collateral pledged under repurchase agreements: Cash $ 1 $ 1 $ 2 $ — $ — $ 2 U.S. Treasury / Agency 109 109 107 — — 107 Mortgage-backed securities 1,350 1,350 399 476 480 1,355 $ 1,460 $ 1,460 $ 508 $ 476 $ 480 $ 1,464 Gross amount of recognized liabilities for repurchase agreements $ 1,409 $ 1,416 Difference (1) $ 51 $ 48 (1) Per the repurchase agreements, the amount of collateral posted is required to exceed the amount of gross liability. Potential risks exist in our secured borrowing transactions due to market conditions and counterparty exposure. With collateral that we pledge, there is a risk that the collateral may not be returned at the expiration of the agreement. If the counterparty fails to return the collateral, Chubb will have free use of the borrowed funds until our collateral is returned. In addition, we may encounter the risk that Chubb may not be able to renew outstanding borrowings with a new term or with an existing counterparty due to market conditions including a decrease in demand as well as more restrictive terms from banks due to increased regulatory and capital constraints. Should this condition occur, Chubb may seek alternative borrowing sources or reduce borrowings. Additionally, increased margins and collateral requirements due to market conditions would increase our restricted assets as we are required to provide additional collateral to support the transaction. d) Fixed maturities At June 30, 2020, we have commitments to purchase fixed income securities of $747 million over the next several years. e) Other investments At June 30, 2020, included in Other investments in the Consolidated balance sheet are investments in limited partnerships and partially-owned investment companies with a carrying value of $4.6 billion. In connection with these investments, we have commitments that may require funding of up to $3.3 billion over the next several years. f) Income taxes At June 30, 2020, $48 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 2010. g) Legal proceedings Our insurance subsidiaries are subject to claims litigation involving disputed interpretations of policy coverages and, in some jurisdictions, direct actions by allegedly-injured persons seeking damages from policyholders. These lawsuits, involving claims on policies issued by our subsidiaries which are typical to the insurance industry in general and in the normal course of business, are considered in our loss and loss expense reserves. In addition to claims litigation, we are subject to lawsuits and regulatory actions in the normal course of business that do not arise from or directly relate to claims on insurance policies. This category of business litigation typically involves, among other things, allegations of underwriting errors or misconduct, employment claims, regulatory activity, or disputes arising from our business ventures. In the opinion of management, our ultimate liability for these matters could be, but we believe is not likely to be, material to our consolidated financial condition and results of operations. h) Leases At June 30, 2020 and December 31, 2019, the right-of-use asset was $483 million and $551 million, respectively, and is recorded within Other assets on the Consolidated balance sheets. At June 30, 2020 and December 31, 2019, the lease liability was $531 million and $603 million, respectively, and is 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.

Shareholders' equity

Shareholders' equity	6 Months Ended
	Jun. 30, 2020
Stockholders' Equity Note [Abstract]
Shareholders' equity	Shareholders’ equity All of Chubb’s Common Shares are authorized under Swiss corporate law. Though the par value of Common Shares is stated in Swiss francs, Chubb continues to use U.S. dollars as its reporting currency for preparing consolidated financial statements. Under Swiss corporate law, dividends, including distributions through a reduction in par value (par value reduction) or from legal reserves, must be stated in Swiss francs though dividend payments are made by Chubb in U.S. dollars. At June 30, 2020, our Common Shares had a par value of CHF 24.15 per share. At our May 2019 and 2018 annual general meetings, our shareholders approved annual dividends for the following year of up to $3.00 per share and $2.92 per share, respectively, which were paid in four quarterly installments of $0.75 per share and $0.73 per share, respectively, at dates determined by the Board of Directors (Board) after the annual general meetings by way of a distribution from capital contribution reserves, transferred to free reserves for payment. At our May 2020 annual general meeting, our shareholders approved an annual dividend for the following year of up to $3.12 per share, expected to be paid in four quarterly installments of $0.78 per share after the general meeting by way of distribution from capital contribution reserves, transferred to free reserves for payment. The Board will determine the record and payment dates at which the annual dividend may be paid until the date of the 2021 annual general meeting, and is authorized to abstain from distributing a dividend at its discretion. The following table presents dividend distributions per Common Share in Swiss francs (CHF) and U.S. dollars (USD): Three Months Ended Six Months Ended June 30 June 30 2020 2019 2020 2019 CHF USD CHF USD CHF USD CHF USD Total dividend distributions per common share 0.75 $ 0.78 0.75 $ 0.75 1.47 $ 1.53 1.47 $ 1.48 Common Shares in treasury are used principally for issuance upon the exercise of employee stock options, grants of restricted stock, and purchases under the Employee Stock Purchase Plan (ESPP). At June 30, 2020, 28,423,841 Common Shares remain in treasury after net shares redeemed under employee share-based compensation plans. Chubb Limited securities repurchase authorizations In December 2018, the Board authorized the repurchase of up to $1.5 billion of Chubb's Common Shares from December 1, 2018 through December 31, 2019. 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. On April 22, 2020, we announced that given the current economic environment and to preserve capital for both risk and opportunity, we had suspended share repurchases. Share repurchases may be resumed at any time, at management's discretion. We did not engage in any share repurchase activity during the three months ended June 30, 2020. 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 Six Months Ended June 30 June 30 (in millions of U.S. dollars, except share data) 2020 2019 2020 2019 Number of shares repurchased — 2,584,466 2,266,150 5,338,220 Cost of shares repurchased $ — $ 376 $ 326 $ 743 Repurchase authorization remaining at end of period $ 1,124 $ 736 $ 1,124 $ 736

Share-based compensation

Share-based compensation	6 Months Ended
	Jun. 30, 2020
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 27, 2020, Chubb granted 1,957,505 stock options with a weighted-average grant date fair value of $19.89 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 27, 2020, Chubb granted 1,002,341 service-based restricted stock awards, 344,501 service-based restricted stock units, and 203,533 performance-based stock awards to employees and officers with a grant date fair value of $150.11 each. Each restricted stock unit represents our obligation to deliver to the holder one Common Share upon vesting.

Postretirement benefits

Postretirement benefits	6 Months Ended
	Jun. 30, 2020
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 (loss) in the Consolidated statements of operations were as follows: Pension Benefit Plans Other Postretirement 2020 2019 2020 2019 Three Months Ended June 30 U.S. Plans Non-U.S. Plans U.S. Plans Non-U.S. Plans (in millions of U.S. dollars) Service cost $ — $ 1 $ 13 $ 2 $ — $ — Non-service cost: Interest cost 25 5 29 7 — 1 Expected return on plan assets (56) (11) (48) (11) (1) (1) Amortization of net actuarial loss — 1 — 1 — — Amortization of prior service cost — — — — (20) (20) Settlements 1 — — — — — Total non-service (benefit) cost (30) (5) (19) (3) (21) (20) Net periodic (benefit) cost $ (30) $ (4) $ (6) $ (1) $ (21) $ (20) Pension Benefit Plans Other Postretirement 2020 2019 2020 2019 Six Months Ended June 30 U.S. Plans Non-U.S. Plans U.S. Plans Non-U.S. Plans (in millions of U.S. dollars) Service cost $ — $ 2 $ 25 $ 5 $ — $ — Non-service cost: Interest cost 50 11 59 14 1 2 Expected return on plan assets (112) (21) (95) (22) (2) (2) Amortization of net actuarial loss — 1 — 1 — — Amortization of prior service cost — — — — (40) (40) Settlements 2 — — — — — Total non-service (benefit) cost (60) (9) (36) (7) (41) (40) Net periodic (benefit) cost $ (60) $ (7) $ (11) $ (2) $ (41) $ (40) The line items in which the service and non-service cost components of net periodic (benefit) cost are included in the Consolidated statements of operations were as follows: Pension Benefit Plans Other Postretirement Benefit Plans Three Months Ended June 30 2020 2019 2020 2019 (in millions of U.S. dollars) Service cost: Losses and loss expenses $ — $ 1 $ — $ — Administrative expenses 1 14 — — Total service cost 1 15 — — Non-service cost: Losses and loss expenses (3) (2) (2) (2) Administrative expenses (32) (20) (19) (18) Total non-service (benefit) cost (35) (22) (21) (20) Net periodic (benefit) cost $ (34) $ (7) $ (21) $ (20) Pension Benefit Plans Other Postretirement Benefit Plans Six Months Ended June 30 2020 2019 2020 2019 (in millions of U.S. dollars) Service cost: Losses and loss expenses $ — $ 3 $ — $ — Administrative expenses 2 27 — — Total service cost 2 30 — — Non-service cost: Losses and loss expenses (6) (4) (4) (4) Administrative expenses (63) (39) (37) (36) Total non-service (benefit) cost (69) (43) (41) (40) Net periodic (benefit) cost $ (67) $ (13) $ (41) $ (40)

Segment information

Segment information	6 Months Ended
	Jun. 30, 2020
Segment Reporting [Abstract]
Segment information	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. For segment reporting purposes, certain items are presented in a different manner below than in the consolidated financial statements. Management uses underwriting income (loss) as the main measure of segment performance. Chubb calculates underwriting income (loss) by subtracting Losses and loss expenses, Policy benefits, Policy acquisition costs, and Administrative expenses from Net premiums earned. To calculate Segment income (loss), include Net investment income (loss), Other (income) expense, and Amortization expense of purchased intangibles. For the North America Agricultural Insurance segment, management includes gains and losses on crop derivatives as a component of underwriting income (loss). For example, for the three months ended June 30, 2020, underwriting income in our North America Agricultural Insurance segment was $31 million. This amount includes $1 million of realized losses related to crop derivatives which are reported in Net realized gains (losses) in the Corporate column below. For the Life Insurance segment, management includes Net investment income (loss) and (Gains) losses from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP as components of Life Insurance underwriting income (loss). For example, for the three months ended June 30, 2020, Life Insurance underwriting income of $71 million includes Net investment income of $95 million and gains from fair value changes in separate account assets of $40 million. The gains from fair value changes in separate account assets are reported in Other (income) expense in the table below. The following tables present the Statement of Operations by segment: For the Three Months Ended North America Commercial P&C Insurance North America Personal P&C Insurance North America Agricultural Insurance Overseas General Insurance Global Life Insurance Corporate Chubb Net premiums written $ 3,720 $ 1,327 $ 461 $ 2,021 $ 207 $ 619 $ — $ 8,355 Net premiums earned 3,595 1,192 376 2,194 163 608 — 8,128 Losses and loss expenses 3,498 762 312 1,485 73 171 276 6,577 Policy benefits — — — — — 223 — 223 Policy acquisition costs 471 231 29 624 42 196 — 1,593 Administrative expenses 249 66 3 241 9 82 77 727 Underwriting income (loss) (623) 133 32 (156) 39 (64) (353) (992) Net investment income (loss) 507 65 7 124 51 95 (22) 827 Other (income) expense 4 1 1 8 (8) (57) 109 58 Amortization expense of purchased intangibles — 3 6 11 — 1 51 72 Segment income (loss) $ (120) $ 194 $ 32 $ (51) $ 98 $ 87 $ (535) $ (295) Net realized gains (losses) 30 30 Interest expense 128 128 Income tax benefit (62) (62) Net loss $ (571) $ (331) For the Three Months Ended North America Commercial P&C Insurance North America Personal P&C Insurance North America Agricultural Insurance Overseas General Insurance Global Life Insurance Corporate Chubb Net premiums written $ 3,534 $ 1,309 $ 466 $ 2,258 $ 197 $ 579 $ — $ 8,343 Net premiums earned 3,390 1,168 378 2,225 159 571 — 7,891 Losses and loss expenses 2,214 747 316 1,125 90 189 34 4,715 Policy benefits — — — — — 161 — 161 Policy acquisition costs 459 237 27 629 42 150 — 1,544 Administrative expenses 259 71 4 265 7 78 74 758 Underwriting income (loss) 458 113 31 206 20 (7) (108) 713 Net investment income (loss) 521 64 4 151 55 97 (33) 859 Other (income) expense 2 1 1 3 (15) (7) (215) (230) Amortization expense of purchased intangibles — 3 7 12 — 1 54 77 Segment income $ 977 $ 173 $ 27 $ 342 $ 90 $ 96 $ 20 $ 1,725 Net realized gains (losses) including OTTI (223) (223) Interest expense 140 140 Chubb integration expenses 4 4 Income tax expense 208 208 Net income (loss) $ (555) $ 1,150 For the Six Months Ended North America Commercial P&C Insurance North America Personal P&C Insurance North America Agricultural Insurance Overseas General Insurance Global Reinsurance Life Insurance Corporate Chubb Consolidated Net premiums written $ 6,972 $ 2,434 $ 618 $ 4,619 $ 425 $ 1,264 $ — $ 16,332 Net premiums earned 6,971 2,392 470 4,501 349 1,239 — 15,922 Losses and loss expenses 5,679 1,445 375 2,743 160 373 287 11,062 Policy benefits — — — — — 352 — 352 Policy acquisition costs 963 476 40 1,266 87 376 — 3,208 Administrative expenses 508 134 7 499 19 158 143 1,468 Underwriting income (loss) (179) 337 48 (7) 83 (20) (430) (168) Net investment income (loss) 1,023 131 16 269 105 190 (46) 1,688 Other (income) expense 1 3 1 12 (23) (13) 132 113 Amortization expense of purchased intangibles — 6 13 23 — 2 101 145 Segment income (loss) $ 843 $ 459 $ 50 $ 227 $ 211 $ 181 $ (709) $ 1,262 Net realized gains (losses) (928) (928) Interest expense 260 260 Income tax expense 153 153 Net loss $ (2,050) $ (79) For the Six Months Ended North America Commercial P&C Insurance North America Personal P&C Insurance North America Agricultural Insurance Overseas General Insurance Global Reinsurance Life Insurance Corporate Chubb Consolidated Net premiums written $ 6,485 $ 2,365 $ 596 $ 4,653 $ 399 $ 1,158 $ — $ 15,656 Net premiums earned 6,475 2,322 433 4,339 327 1,132 — 15,028 Losses and loss expenses 4,187 1,504 289 2,231 166 391 45 8,813 Policy benefits — — — — — 357 — 357 Policy acquisition costs 918 468 34 1,225 85 278 — 3,008 Administrative expenses 499 139 5 514 17 157 137 1,468 Underwriting income (loss) 871 211 105 369 59 (51) (182) 1,382 Net investment income (loss) 1,031 128 14 295 111 186 (70) 1,695 Other (income) expense (3) 1 1 7 (24) (47) (204) (269) Amortization expense of purchased intangibles — 6 14 23 — 1 109 153 Segment income (loss) $ 1,905 $ 332 $ 104 $ 634 $ 194 $ 181 $ (157) $ 3,193 Net realized gains (losses) including OTTI (320) (320) Interest expense 280 280 Chubb integration expenses 7 7 Income tax expense 396 396 Net income (loss) $ (1,160) $ 2,190 Underwriting assets are reviewed in total by management for purposes of decision-making. Other than Unpaid losses and loss expenses, Reinsurance recoverables, Goodwill and Other intangible assets, Chubb does not allocate assets to its segments.

Earnings per share

Earnings per share	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Earnings per share	Earnings per share Three Months Ended Six Months Ended June 30 June 30 (in millions of U.S. dollars, except share and per share data) 2020 2019 2020 2019 Numerator: Net income (loss) $ (331) $ 1,150 $ (79) $ 2,190 Denominator: Denominator for basic earnings per share: Weighted-average shares outstanding 451,402,807 457,224,455 451,635,733 458,010,447 Denominator for diluted earnings per share: Share-based compensation plans (1) — 2,945,237 — 2,863,109 Weighted-average shares outstanding and assumed conversions 451,402,807 460,169,692 451,635,733 460,873,556 Basic earnings (loss) per share $ (0.73) $ 2.52 $ (0.17) $ 4.78 Diluted earnings (loss) per share $ (0.73) $ 2.50 $ (0.17) $ 4.75 Potential anti-dilutive share conversions 8,378,447 2,660,925 6,583,319 5,037,959 (1) For the three and six months ended June 30, 2020, weighted-average shares outstanding used in calculating diluted loss per share excludes the effect of dilutive securities of 1,395,951 and 2,044,144 shares, respectively. In periods where a net loss is recognized, inclusion of incremental dilution is antidilutive. 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 connect

Information provided in connection with outstanding debt of subsidiaries	6 Months Ended
	Jun. 30, 2020
Disclosure Text Block Supplement [Abstract]
Information provided in connection with outstanding debt of subsidiaries	Information provided in connection with outstanding debt of subsidiaries The following tables present condensed consolidating financial information at June 30, 2020 and December 31, 2019, and for the three and six months ended June 30, 2020 and 2019 for Chubb Limited (Parent Guarantor) and Chubb INA Holdings Inc. (Subsidiary Issuer). The Subsidiary Issuer is an indirect 100 percent-owned subsidiary of the Parent Guarantor. The Parent Guarantor fully and unconditionally guarantees certain of the debt of the Subsidiary Issuer. Condensed consolidating financial information of the Parent Guarantor and Subsidiary Issuer are presented on the equity method of accounting. The revenues and expenses and cash flows of the subsidiaries of the Subsidiary Issuer are presented in the Other Chubb Limited Subsidiaries column on a combined basis. Condensed Consolidating Balance Sheet at June 30, 2020 (in millions of U.S. dollars) Chubb Chubb INA Other Chubb Consolidating Chubb Limited Assets Investments $ — $ 195 $ 110,682 $ — $ 110,877 Cash (1) 1 — 2,624 (1,068) 1,557 Restricted cash — — 152 — 152 Insurance and reinsurance balances receivable — — 13,637 (2,784) 10,853 Reinsurance recoverable on losses and loss expenses — — 24,804 (9,597) 15,207 Reinsurance recoverable on policy benefits — — 292 (95) 197 Value of business acquired — — 290 — 290 Goodwill and other intangible assets — — 21,093 — 21,093 Investments in subsidiaries 52,339 52,752 — (105,091) — Due from subsidiaries and affiliates, net 3,636 — — (3,636) — Other assets 8 336 22,858 (1,954) 21,248 Total assets $ 55,984 $ 53,283 $ 196,432 $ (124,225) $ 181,474 Liabilities Unpaid losses and loss expenses $ — $ — $ 75,013 $ (9,314) $ 65,699 Unearned premiums — — 18,301 (1,220) 17,081 Future policy benefits — — 5,990 (95) 5,895 Due to subsidiaries and affiliates, net — 3,365 271 (3,636) — Affiliated notional cash pooling programs (1) 882 186 — (1,068) — Repurchase agreements — — 1,409 — 1,409 Short-term debt — 1,300 — — 1,300 Long-term debt — 13,656 — — 13,656 Trust preferred securities — 308 — — 308 Other liabilities 342 1,415 23,410 (3,801) 21,366 Total liabilities 1,224 20,230 124,394 (19,134) 126,714 Total shareholders’ equity 54,760 33,053 72,038 (105,091) 54,760 Total liabilities and shareholders’ equity $ 55,984 $ 53,283 $ 196,432 $ (124,225) $ 181,474 (1) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive. Condensed Consolidating Balance Sheet at December 31, 2019 (in millions of U.S. dollars) Chubb Chubb INA Other Chubb Consolidating Chubb Limited Assets Investments $ — $ 1,013 $ 108,221 $ — $ 109,234 Cash (1) 2 442 1,093 — 1,537 Restricted cash — — 109 — 109 Insurance and reinsurance balances receivable — — 12,920 (2,563) 10,357 Reinsurance recoverable on losses and loss expenses — — 24,780 (9,599) 15,181 Reinsurance recoverable on policy benefits — — 292 (95) 197 Value of business acquired — — 306 — 306 Goodwill and other intangible assets — — 21,359 — 21,359 Investments in subsidiaries 50,853 52,076 — (102,929) — Due from subsidiaries and affiliates, net 4,776 — — (4,776) — Other assets 12 408 20,072 (1,829) 18,663 Total assets $ 55,643 $ 53,939 $ 189,152 $ (121,791) $ 176,943 Liabilities Unpaid losses and loss expenses $ — $ — $ 71,916 $ (9,226) $ 62,690 Unearned premiums — — 17,978 (1,207) 16,771 Future policy benefits — — 5,909 (95) 5,814 Due to subsidiaries and affiliates, net — 4,446 330 (4,776) — Repurchase agreements — — 1,416 — 1,416 Short-term debt — 1,298 1 — 1,299 Long-term debt — 13,559 — — 13,559 Trust preferred securities — 308 — — 308 Other liabilities 312 1,649 21,352 (3,558) 19,755 Total liabilities 312 21,260 118,902 (18,862) 121,612 Total shareholders’ equity 55,331 32,679 70,250 (102,929) 55,331 Total liabilities and shareholders’ equity $ 55,643 $ 53,939 $ 189,152 $ (121,791) $ 176,943 (1) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to the 2019 Form 10-K for additional information. Condensed Consolidating Statements of Operations and Comprehensive Income (Loss) For the Three Months Ended June 30, 2020 Chubb Chubb INA Other Chubb Consolidating Chubb (in millions of U.S. dollars) Net premiums written $ — $ — $ 8,355 $ — $ 8,355 Net premiums earned — — 8,128 — 8,128 Net investment income — 1 826 — 827 Equity in earnings of subsidiaries (366) (271) — 637 — Net realized gains (losses) 23 (192) 199 — 30 Losses and loss expenses — — 6,577 — 6,577 Policy benefits — — 223 — 223 Policy acquisition costs and administrative expenses 21 (30) 2,329 — 2,320 Interest (income) expense (35) 149 14 — 128 Other (income) expense (8) (5) 71 — 58 Amortization of purchased intangibles — — 72 — 72 Income tax expense (benefit) 10 (66) (6) — (62) Net loss $ (331) $ (510) $ (127) $ 637 $ (331) Comprehensive income $ 2,860 $ 1,872 $ 3,078 $ (4,950) $ 2,860 Condensed Consolidating Statements of Operations and Comprehensive Income For the Three Months Ended June 30, 2019 Chubb Chubb INA Other Chubb Consolidating Chubb (in millions of U.S. dollars) Net premiums written $ — $ — $ 8,343 $ — $ 8,343 Net premiums earned — — 7,891 — 7,891 Net investment income 1 (6) 864 — 859 Equity in earnings of subsidiaries 1,104 762 — (1,866) — Net realized gains (losses) including OTTI 4 (21) (206) — (223) Losses and loss expenses — — 4,715 — 4,715 Policy benefits — — 161 — 161 Policy acquisition costs and administrative expenses 22 (5) 2,285 — 2,302 Interest (income) expense (62) 180 22 — 140 Other (income) expense (6) 1 (225) — (230) Amortization of purchased intangibles — — 77 — 77 Chubb integration expenses — — 4 — 4 Income tax expense (benefit) 5 (45) 248 — 208 Net income $ 1,150 $ 604 $ 1,262 $ (1,866) $ 1,150 Comprehensive income $ 2,059 $ 1,397 $ 2,181 $ (3,578) $ 2,059 Condensed Consolidating Statements of Operations and Comprehensive Income For the Six Months Ended June 30, 2020 Chubb Limited (Parent Guarantor) Chubb INA Holdings Inc. (Subsidiary Issuer) Other Chubb Limited Subsidiaries Consolidating Adjustments and Eliminations Chubb Limited Consolidated (in millions of U.S. dollars) Net premiums written $ — $ — $ 16,332 $ — $ 16,332 Net premiums earned — — 15,922 — 15,922 Net investment income (2) 5 1,685 — 1,688 Equity in earnings of subsidiaries (110) 322 — (212) — Net realized gains (losses) 2 (79) (851) — (928) Losses and loss expenses — — 11,062 — 11,062 Policy benefits — — 352 — 352 Policy acquisition costs and administrative expenses 45 (68) 4,699 — 4,676 Interest (income) expense (69) 297 32 — 260 Other (income) expense (17) 3 127 — 113 Amortization of purchased intangibles — — 145 — 145 Income tax expense (benefit) 10 (59) 202 — 153 Net income (loss) $ (79) $ 75 $ 137 $ (212) $ (79) Comprehensive income $ 400 $ 672 $ 660 $ (1,332) $ 400 Condensed Consolidating Statements of Operations and Comprehensive Income For the Six Months Ended June 30, 2019 Chubb Limited (Parent Guarantor) Chubb INA Holdings Inc. (Subsidiary Issuer) Other Chubb Limited Subsidiaries Consolidating Adjustments and Eliminations Chubb Limited Consolidated (in millions of U.S. dollars) Net premiums written $ — $ — $ 15,656 $ — $ 15,656 Net premiums earned — — 15,028 — 15,028 Net investment income 2 (10) 1,703 — 1,695 Equity in earnings of subsidiaries 2,094 1,521 — (3,615) — Net realized gains (losses) including OTTI 5 (34) (291) — (320) Losses and loss expenses — — 8,813 — 8,813 Policy benefits — — 357 — 357 Policy acquisition costs and administrative expenses 42 (20) 4,454 — 4,476 Interest (income) expense (128) 365 43 — 280 Other (income) expense (12) 4 (261) — (269) Amortization of purchased intangibles — — 153 — 153 Chubb integration expenses — 2 5 — 7 Income tax expense (benefit) 9 (87) 474 — 396 Net income $ 2,190 $ 1,213 $ 2,402 $ (3,615) $ 2,190 Comprehensive income $ 4,777 $ 3,338 $ 4,969 $ (8,307) $ 4,777 Condensed Consolidating Statement of Cash Flows Six Months Ended June 30, 2020 Chubb Chubb INA Other Chubb Consolidating Chubb (in millions of U.S. dollars) Net cash flows from (used for) operating activities $ 181 $ (307) $ 3,933 $ (110) $ 3,697 Cash flows from investing activities Purchases of fixed maturities available for sale — (13) (13,045) — (13,058) Purchases of fixed maturities held to maturity — — (42) — (42) Purchases of equity securities — — (2,824) — (2,824) Sales of fixed maturities available for sale — 7 7,727 — 7,734 Sales of equity securities — — 1,353 — 1,353 Maturities and redemptions of fixed maturities available for sale — 29 5,191 — 5,220 Maturities and redemptions of fixed maturities held to maturity — — 642 — 642 Net change in short-term investments — 761 (588) — 173 Net derivative instruments settlements — 69 (87) — (18) Private equity contributions — — (546) — (546) Private equity distributions — — 443 — 443 Deposit paid on share acquisition — — (1,550) — (1,550) Capital contribution (1,200) — — 1,200 — Other (1) (3) (217) — (221) Net cash flows from (used for) investing activities (1,201) 850 (3,543) 1,200 (2,694) Cash flows from financing activities Dividends paid on Common Shares (678) — — — (678) Common Shares repurchased (333) — — — (333) Proceeds from issuance of repurchase agreements — — 1,402 — 1,402 Repayment of repurchase agreements — — (1,402) — (1,402) Proceeds from share-based compensation plans — — 74 — 74 Dividend to parent company — — (110) 110 — Advances (to) from affiliates 1,149 (1,168) 19 — — Capital contribution — — 1,200 (1,200) — Net proceeds from (payments to) affiliated notional cash pooling programs (1) 882 186 — (1,068) — Policyholder contract deposits — — 215 — 215 Policyholder contract withdrawals — — (173) — (173) Other — (3) — — (3) Net cash flows from (used for) financing activities 1,020 (985) 1,225 (2,158) (898) Effect of foreign currency rate changes on cash and restricted cash (1) — (41) — (42) Net increase (decrease) in cash and restricted cash (1) (442) 1,574 (1,068) 63 Cash and restricted cash – beginning of period (1) 2 442 1,202 — 1,646 Cash and restricted cash – end of period (1) $ 1 $ — $ 2,776 $ (1,068) $ 1,709 (1) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020 and December 31, 2019, the cash balance of one or more entities was negative; however, the overall Pool balances were positive. Condensed Consolidating Statement of Cash Flows Six Months Ended June 30, 2019 Chubb Chubb INA Other Chubb Consolidating Chubb (in millions of U.S. dollars) Net cash flows from operating activities $ 323 $ 1,302 $ 2,943 $ (1,860) $ 2,708 Cash flows from investing activities Purchases of fixed maturities available for sale — (5) (12,561) — (12,566) Purchases of fixed maturities held to maturity — — (73) — (73) Purchases of equity securities — — (147) — (147) Sales of fixed maturities available for sale — — 7,838 — 7,838 Sales of equity securities — — 266 — 266 Maturities and redemptions of fixed maturities available for sale — 16 3,947 — 3,963 Maturities and redemptions of fixed maturities held to maturity — — 598 — 598 Net change in short-term investments — (11) (752) — (763) Net derivative instruments settlements — (35) (501) — (536) Private equity contributions — — (920) — (920) Private equity distributions — — 780 — 780 Capital contribution (600) (110) — 710 — Other — (12) (715) — (727) Net cash flows used for investing activities (600) (157) (2,240) 710 (2,287) Cash flows from financing activities Dividends paid on Common Shares (671) — — — (671) Common Shares repurchased — — (741) — (741) Proceeds from issuance of long-term debt — 1,289 — — 1,289 Repayment of long-term debt — (500) — — (500) Proceeds from issuance of repurchase agreements — — 1,984 — 1,984 Repayment of repurchase agreements — — (1,986) — (1,986) Proceeds from share-based compensation plans — — 95 — 95 Dividend to parent company — — (1,860) 1,860 — Advances (to) from affiliates 801 (1,498) 697 — — Capital contribution — — 710 (710) — Net proceeds from (payments to) affiliated notional cash pooling programs (1) 142 (437) — 295 — Policyholder contract deposits — — 237 — 237 Policyholder contract withdrawals — — (138) — (138) Other — — — — — Net cash flows from (used for) financing activities 272 (1,146) (1,002) 1,445 (431) Effect of foreign currency rate changes on cash and restricted cash 5 — 33 — 38 Net increase (decrease) in cash and restricted cash — (1) (266) 295 28 Cash and restricted cash – beginning of period (1) 1 2 1,989 (652) 1,340 Cash and restricted cash – end of period (1) $ 1 $ 1 $ 1,723 $ (357) $ 1,368 (1) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2019 and December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

General (Policies)

General (Policies)	6 Months Ended
	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation	Basis of presentation Chubb Limited is a holding company incorporated in Zurich, Switzerland. Chubb Limited, through its subsidiaries, provides a broad range of insurance and reinsurance products to insureds worldwide. Our results are reported through the following business segments: North America Commercial P&C Insurance, North America Personal P&C Insurance, North America Agricultural Insurance, Overseas General Insurance, Global Reinsurance, and Life Insurance. Refer to Note 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 2019 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: June 30 December 31 (in millions of U.S. dollars) 2020 2019 Cash $ 1,557 $ 1,537 Restricted cash 152 109 Total cash and restricted cash shown in the Consolidated statements of cash flows $ 1,709 $ 1,646
Accounting guidance adopted in current year	Accounting guidance adopted in 2020 Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments Effective January 1, 2020, we adopted, on a modified retrospective basis, new guidance on the accounting for credit losses of financial instruments that are measured at amortized cost, including held to maturity securities, and reinsurance recoverables, by applying an approach based on the current expected credit losses (CECL). The estimate of expected credit losses considers historical information, current information, as well as reasonable and supportable forecasts, including estimates of prepayments. In addition, the guidance also replaced the current available for sale (AFS) security other-than-temporary impairment model by requiring an estimate of the expected credit loss (ECL) only when the fair value is below the amortized cost of the asset. The length of time the fair value of an AFS security has been below its amortized cost no longer impacts the determination of whether a potential credit loss exists. The AFS security model also requires the use of a valuation allowance as compared to the previous practice of writing down the asset. In 2020, we recognized a cumulative effect adjustment and decreased beginning retained earnings by $79 million pre-tax, or $72 million after-tax, principally related to the valuation allowance for credit losses. We also adopted the required disclosures within Note 3 Investments and Note 5 Reinsurance. Results for reporting periods prior to January 1, 2020 are presented in accordance with the previous guidance.
Accounting guidance not yet adopted	Accounting guidance not yet adopted Effects of Reference Rate Reform on Financial Reporting In March 2020, the FASB issued guidance which provides optional expedients and exceptions for applying GAAP to investments, derivatives, or other transactions that reference the London Interbank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of reference rate reform. Along with the optional expedients, the amendments include a general principle that permits an entity to consider contract modifications due to reference reform to be an event that does not require contract re-measurement at the modification date or reassessment of a previous accounting determination. Additionally, a company may make a one-time election to sell, transfer, or both sell and transfer debt securities classified as held to maturity that reference a rate affected by reference rate reform and that were classified as held to maturity before January 1, 2020. This standard may be elected over time through December 31, 2022 as reference rate reform activities occur. We are currently assessing the effect of adopting this guidance on our financial condition and results of operations. 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 2022 with early adoption permitted. However, in July 2020, the FASB proposed to defer the adoption date by one year, therefore, if the guidance is amended, this standard will be effective for us in the first quarter of 2023. 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 Va

Fair value measurements Fair Value Measurement Policy (Policies)	6 Months Ended
	Jun. 30, 2020
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)

General General (Tables)	6 Months Ended
	Jun. 30, 2020
Cash and Cash Equivalents [Abstract]
Schedule of Cash and Cash Equivalents [Table Text Block]	The following table provides a reconciliation of cash and restricted cash reported within the Consolidated balance sheets that total to the amounts shown in the Consolidated statements of cash flows: June 30 December 31 (in millions of U.S. dollars) 2020 2019 Cash $ 1,557 $ 1,537 Restricted cash 152 109 Total cash and restricted cash shown in the Consolidated statements of cash flows $ 1,709 $ 1,646

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Schedule Of Amortized Cost And Fair Value Of HTM Fixed Maturities And Related OTTI Recognized In AOCI	June 30, 2020 Amortized Valuation Allowance Gross Gross Fair (in millions of U.S. dollars) Available for sale U.S. Treasury / Agency $ 2,636 $ — $ 239 $ — $ 2,875 Non-U.S. 23,370 (17) 1,420 (166) 24,607 Corporate and asset-backed securities 32,721 (52) 1,658 (410) 33,917 Mortgage-backed securities 17,165 — 1,051 (18) 18,198 Municipal 6,848 — 270 (3) 7,115 $ 82,740 $ (69) $ 4,638 $ (597) $ 86,712 Amortized Valuation Allowance Net Carrying Value Gross Gross Fair Held to maturity U.S. Treasury / Agency $ 1,242 $ — $ 1,242 $ 73 $ — $ 1,315 Non-U.S. 1,278 (8) 1,270 102 (2) 1,370 Corporate and asset-backed securities 2,232 (41) 2,191 247 (10) 2,428 Mortgage-backed securities 2,189 (1) 2,188 146 (3) 2,331 Municipal 4,955 (1) 4,954 223 (1) 5,176 $ 11,896 $ (51) $ 11,845 $ 791 $ (16) $ 12,620 December 31, 2019 Amortized Gross Gross Fair OTTI Recognized (in millions of U.S. dollars) Available for sale U.S. Treasury / Agency $ 3,188 $ 96 $ (1) $ 3,283 $ — Non-U.S. 22,670 1,099 (62) 23,707 (25) Corporate and asset-backed securities 30,689 1,180 (78) 31,791 (5) Mortgage-backed securities 18,712 494 (14) 19,192 — Municipal 7,321 205 (11) 7,515 — $ 82,580 $ 3,074 $ (166) $ 85,488 $ (30) Held to maturity U.S. Treasury / Agency $ 1,318 $ 29 $ — $ 1,347 $ — Non-U.S. 1,423 62 — 1,485 — Corporate and asset-backed securities 2,349 121 (2) 2,468 — Mortgage-backed securities 2,331 65 — 2,396 — Municipal 5,160 150 (1) 5,309 — $ 12,581 $ 427 $ (3) $ 13,005 $ —
Schedule Of Amortized Cost and Fair Value of Available-for-sale Securities and Related OTTI Recognized in AOCI	June 30, 2020 Amortized Valuation Allowance Gross Gross Fair (in millions of U.S. dollars) Available for sale U.S. Treasury / Agency $ 2,636 $ — $ 239 $ — $ 2,875 Non-U.S. 23,370 (17) 1,420 (166) 24,607 Corporate and asset-backed securities 32,721 (52) 1,658 (410) 33,917 Mortgage-backed securities 17,165 — 1,051 (18) 18,198 Municipal 6,848 — 270 (3) 7,115 $ 82,740 $ (69) $ 4,638 $ (597) $ 86,712 Amortized Valuation Allowance Net Carrying Value Gross Gross Fair Held to maturity U.S. Treasury / Agency $ 1,242 $ — $ 1,242 $ 73 $ — $ 1,315 Non-U.S. 1,278 (8) 1,270 102 (2) 1,370 Corporate and asset-backed securities 2,232 (41) 2,191 247 (10) 2,428 Mortgage-backed securities 2,189 (1) 2,188 146 (3) 2,331 Municipal 4,955 (1) 4,954 223 (1) 5,176 $ 11,896 $ (51) $ 11,845 $ 791 $ (16) $ 12,620 December 31, 2019 Amortized Gross Gross Fair OTTI Recognized (in millions of U.S. dollars) Available for sale U.S. Treasury / Agency $ 3,188 $ 96 $ (1) $ 3,283 $ — Non-U.S. 22,670 1,099 (62) 23,707 (25) Corporate and asset-backed securities 30,689 1,180 (78) 31,791 (5) Mortgage-backed securities 18,712 494 (14) 19,192 — Municipal 7,321 205 (11) 7,515 — $ 82,580 $ 3,074 $ (166) $ 85,488 $ (30) Held to maturity U.S. Treasury / Agency $ 1,318 $ 29 $ — $ 1,347 $ — Non-U.S. 1,423 62 — 1,485 — Corporate and asset-backed securities 2,349 121 (2) 2,468 — Mortgage-backed securities 2,331 65 — 2,396 — Municipal 5,160 150 (1) 5,309 — $ 12,581 $ 427 $ (3) $ 13,005 $ —
Schedule Of Fixed Maturities By Contractual Maturity	The following table presents fixed maturities by contractual maturity: June 30 December 31 2020 2019 (in millions of U.S. dollars) Net Carrying Value Fair Value Amortized Cost Fair Value Available for sale Due in 1 year or less $ 4,487 $ 4,487 $ 3,951 $ 3,973 Due after 1 year through 5 years 26,867 26,867 27,142 27,720 Due after 5 years through 10 years 25,465 25,465 23,901 24,874 Due after 10 years 11,695 11,695 8,874 9,729 68,514 68,514 63,868 66,296 Mortgage-backed securities 18,198 18,198 18,712 19,192 $ 86,712 $ 86,712 $ 82,580 $ 85,488 Held to maturity Due in 1 year or less $ 890 $ 902 $ 478 $ 479 Due after 1 year through 5 years 3,505 3,662 3,869 3,940 Due after 5 years through 10 years 3,328 3,516 3,756 3,883 Due after 10 years 1,934 2,209 2,147 2,307 9,657 10,289 10,250 10,609 Mortgage-backed securities 2,188 2,331 2,331 2,396 $ 11,845 $ 12,620 $ 12,581 $ 13,005
Schedule of Realized Gain (Loss)	The following table presents the components of Net realized gains (losses): Three Months Ended Six Months Ended June 30 June 30 (in millions of U.S. dollars) 2020 2019 2020 2019 Fixed maturities: OTTI on fixed maturities, gross $ — $ (14) $ — $ (27) OTTI on fixed maturities recognized in OCI (pre-tax) — 1 — 1 OTTI on fixed maturities, net — (13) — (26) Gross realized gains excluding OTTI 68 56 145 83 Gross realized losses excluding OTTI (174) (31) (299) (89) Provision for expected credit losses 104 — (46) — Impairment (1) (31) — (152) — Total fixed maturities $ (33) $ 12 $ (352) $ (32) Equity securities 148 5 119 63 Other investments (107) 30 (102) (14) Foreign exchange gains (losses) (61) (11) (129) 2 Investment and embedded derivative instruments 14 (181) 29 (311) Fair value adjustments on insurance derivative 213 (65) (472) 49 S&P futures (103) (20) 22 (83) Other derivative instruments (1) 7 (3) 6 Other (40) — (40) — Net realized gains (losses) (pre-tax) $ 30 $ (223) $ (928) $ (320) (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 June 30 2020 2019 (in millions of U.S. dollars) Equity Securities Other Investments Total Equity Securities Other Investments Total Net gains (losses) recognized during the period $ 148 $ (107) $ 41 $ 5 $ 30 $ 35 Less: Net gains (losses) recognized from sales of securities 187 — 187 32 — 32 Unrealized gains (losses) recognized for securities still held at reporting date $ (39) $ (107) $ (146) $ (27) $ 30 $ 3 Six Months Ended June 30 2020 2019 (in millions of U.S. dollars) Equity Securities Other Investments Total Equity Securities Other Investments Total Net gains (losses) recognized during the period $ 119 $ (102) $ 17 $ 63 $ (14) $ 49 Less: Net gains (losses) recognized from sales of securities 163 — 163 33 (2) 31 Unrealized gains (losses) recognized for securities still held at reporting date $ (44) $ (102) $ (146) $ 30 $ (12) $ 18
Schedule Of Aggregate Fair Value And Gross Unrealized Loss By Length Of Time The Security Has Continuously Been In An Unrealized Loss Position	The following table presents, for AFS fixed maturities in an unrealized loss position (including securities on loan) that are not deemed to have credit losses, the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position: 0 – 12 Months Over 12 Months Total June 30, 2020 Fair Value Gross Fair Value Gross Fair Value Gross (in millions of U.S. dollars) Non-U.S. $ 3,172 $ (117) $ 105 $ (22) $ 3,277 $ (139) Corporate and asset-backed securities 7,985 (295) 551 (35) 8,536 (330) Mortgage-backed securities 953 (13) 27 (2) 980 (15) Municipal 95 (1) 65 (2) 160 (3) Total AFS fixed maturities $ 12,205 $ (426) $ 748 $ (61) $ 12,953 $ (487) The following table presents, for all securities in an unrealized loss position (including securities on loan), the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position: 0 – 12 Months Over 12 Months Total December 31, 2019 Fair Value Gross Fair Value Gross Fair Value Gross (in millions of U.S. dollars) U.S. Treasury / Agency $ 234 $ (1) $ 339 $ — $ 573 $ (1) Non-U.S. 1,846 (34) 802 (28) 2,648 (62) Corporate and asset-backed securities 2,121 (40) 988 (40) 3,109 (80) Mortgage-backed securities 1,174 (6) 932 (8) 2,106 (14) Municipal 188 — 276 (12) 464 (12) Total fixed maturities $ 5,563 $ (81) $ 3,337 $ (88) $ 8,900 $ (169)
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: June 30, 2020 (in millions of U.S. dollars) Amortized cost % of Total AAA $ 2,583 22 % AA 6,397 54 % A 2,302 19 % BBB 591 5 % BB 21 — % Other 2 — % Total $ 11,896 100 %
Schedule Of Components Of Restricted Assets	The following table presents the components of restricted assets: June 30 December 31 (in millions of U.S. dollars) 2020 2019 Trust funds $ 12,522 $ 14,004 Deposits with U.S. regulatory authorities 2,424 2,466 Deposits with non-U.S. regulatory authorities 2,807 2,709 Assets pledged under repurchase agreements 1,460 1,464 Other pledged assets 523 490 Total $ 19,736 $ 21,133
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 Six Months Ended June 30 June 30 (in millions of U.S. dollars) 2020 2020 Available for sale Valuation allowance for expected credit losses - beginning of period $ 176 $ — Impact of adoption of new accounting guidance — 25 Provision for expected credit loss 29 178 Initial allowance for purchased securities with credit deterioration 3 5 Write-offs charged against the expected credit loss (5) (5) Recovery of expected credit loss (134) (134) Valuation allowance for expected credit losses - end of period $ 69 $ 69 Held to maturity Valuation allowance for expected credit losses - beginning of period $ 45 $ — Impact of adoption of new accounting guidance — 44 Provision for expected credit loss 6 7 Valuation allowance for expected credit losses - end of period $ 51 $ 51
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 Six Months Ended June 30 June 30 (in millions of U.S. dollars) 2020 2020 Available for sale Valuation allowance for expected credit losses - beginning of period $ 176 $ — Impact of adoption of new accounting guidance — 25 Provision for expected credit loss 29 178 Initial allowance for purchased securities with credit deterioration 3 5 Write-offs charged against the expected credit loss (5) (5) Recovery of expected credit loss (134) (134) Valuation allowance for expected credit losses - end of period $ 69 $ 69 Held to maturity Valuation allowance for expected credit losses - beginning of period $ 45 $ — Impact of adoption of new accounting guidance — 44 Provision for expected credit loss 6 7 Valuation allowance for expected credit losses - end of period $ 51 $ 51
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table Text Block]	June 30 December 31 Expected 2020 2019 (in millions of U.S. dollars) Fair Maximum Fair Maximum Financial 2 to 10 Years $ 521 $ 309 $ 611 $ 329 Real Assets 2 to 11 Years 674 749 712 422 Distressed 2 to 8 Years 220 158 263 80 Private Credit 3 to 8 Years 81 272 104 272 Traditional 2 to 14 Years 3,039 1,852 2,844 2,160 Vintage 1 to 2 Years 90 — 116 — Investment funds Not Applicable 228 — 271 — $ 4,853 $ 3,340 $ 4,921 $ 3,263

Fair value measurements (Tables

Fair value measurements (Tables)	6 Months Ended
	Jun. 30, 2020
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 June 30, 2020 Level 1 Level 2 Level 3 Total (in millions of U.S. dollars) Assets: Fixed maturities available for sale U.S. Treasury / Agency $ 2,316 $ 559 $ — $ 2,875 Non-U.S. — 24,138 469 24,607 Corporate and asset-backed securities — 32,548 1,369 33,917 Mortgage-backed securities — 18,138 60 18,198 Municipal — 7,115 — 7,115 2,316 82,498 1,898 86,712 Equity securities 2,329 1 64 2,394 Short-term investments 2,707 1,294 2 4,003 Other investments (1) 361 383 10 754 Securities lending collateral — 1,832 — 1,832 Investment derivative instruments 19 — — 19 Other derivative instruments 1 — — 1 Separate account assets 3,394 132 — 3,526 Total assets measured at fair value (1) $ 11,127 $ 86,140 $ 1,974 $ 99,241 Liabilities: Investment derivative instruments $ 96 $ — $ — $ 96 GLB (2) — — 928 928 Total liabilities measured at fair value $ 96 $ — $ 928 $ 1,024 (1) Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,853 million, policy loans of $226 million and other investments of $90 million at June 30, 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. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. December 31, 2019 Level 1 Level 2 Level 3 Total (in millions of U.S. dollars) Assets: Fixed maturities available for sale U.S. Treasury / Agency $ 2,664 $ 619 $ — $ 3,283 Non-U.S. — 23,258 449 23,707 Corporate and asset-backed securities — 30,340 1,451 31,791 Mortgage-backed securities — 19,132 60 19,192 Municipal — 7,515 — 7,515 2,664 80,864 1,960 85,488 Equity securities 728 15 69 812 Short-term investments 2,803 1,482 6 4,291 Other investments (1) 412 377 10 799 Securities lending collateral — 994 — 994 Investment derivative instruments 24 — — 24 Other derivative instruments 2 — — 2 Separate account assets 3,437 136 — 3,573 Total assets measured at fair value (1) $ 10,070 $ 83,868 $ 2,045 $ 95,983 Liabilities: Investment derivative instruments $ 93 $ — $ — $ 93 Other derivative instruments 13 — — 13 GLB (2) — — 456 456 Total liabilities measured at fair value $ 106 $ — $ 456 $ 562 (1) Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,921 million and other investments of $95 million at December 31, 2019 measured using NAV as a practical expedient. (2) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.
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 Significant Ranges Weighted Average (1) June 30, 2020 December 31, 2019 GLB (1) $ 928 $ 456 Actuarial model Lapse rate 3% – 34% 4.6 % Annuitization rate 0% – 52% 4.1 %
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	The following tables present a reconciliation of the beginning and ending balances of financial instruments measured at fair value using significant unobservable inputs (Level 3): Assets Liabilities Three Months Ended Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 465 $ 1,502 $ 60 $ 67 $ 1 $ 10 $ 1,141 Transfers out of Level 3 (13) (71) — — — — — Change in Net Unrealized Gains (Losses) in OCI (6) 1 — (1) — — — Net Realized Gains/Losses (1) (13) — (1) — — (213) Purchases 67 83 — 8 1 — — Sales (16) (48) — (9) — — — Settlements (27) (85) — — — — — Balance – end of period $ 469 $ 1,369 $ 60 $ 64 $ 2 $ 10 $ 928 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ 5 $ — $ 1 $ — $ — $ (213) Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date $ (5) $ 7 $ — $ — $ — $ — $ — (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $1,372 million at June 30, 2020, and $1,591 million at March 31, 2020, which includes a fair value derivative adjustment of $928 million and $1,141 million, respectively. Assets Liabilities Three Months Ended Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 360 $ 1,342 $ 78 $ 55 $ — $ 11 $ 338 Transfers into Level 3 — 10 — — — — — Change in Net Unrealized Gains/Losses in OCI, including foreign exchange — 1 — 1 — — — Net Realized Gains/Losses — (1) — (1) — — 65 Purchases 43 121 — 5 4 — — Sales (14) (36) (1) (4) — — — Settlements (18) (78) (1) — — — — Balance – end of period $ 371 $ 1,359 $ 76 $ 56 $ 4 $ 11 $ 403 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ (1) $ — $ (1) $ — $ — $ 65 (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $815 million at June 30, 2019, and $741 million at March 31, 2019, which includes a fair value derivative adjustment of $403 million and $338 million, respectively. Assets Liabilities Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Six Months Ended Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 449 $ 1,451 $ 60 $ 69 $ 6 $ 10 $ 456 Transfers into Level 3 — 91 — — — — — Transfers out of Level 3 (16) (72) — — — — — Change in Net Unrealized Gains (Losses) in OCI, including foreign exchange (20) (44) — — — — — Net Realized Gains/Losses (3) (26) — (3) — — 472 Purchases 149 222 — 11 2 — — Sales (62) (67) — (13) — — — Settlements (28) (186) — — (6) — — Balance – end of period $ 469 $ 1,369 $ 60 $ 64 $ 2 $ 10 $ 928 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ (9) $ — $ (1) $ — $ — $ 472 Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date $ (20) $ (37) $ — $ — $ — $ — $ — (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $1,372 million at June 30, 2020, and $897 million at December 31, 2019, which includes a fair value derivative adjustment of $928 million and $456 million, respectively. Assets Liabilities Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Six Months Ended Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 345 $ 1,299 $ 61 $ 57 $ 1 $ 11 $ 452 Transfers into Level 3 3 15 — — — — — Transfers out of Level 3 (15) — — — — — — Change in Net Unrealized Gains/Losses in OCI, including foreign exchange 6 5 — 2 — — — Net Realized Gains/Losses (1) — — (3) — — (49) Purchases 96 249 18 14 4 — — Sales (19) (73) (1) (14) — — — Settlements (44) (136) (2) — (1) — — Balance – end of period $ 371 $ 1,359 $ 76 $ 56 $ 4 $ 11 $ 403 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ (1) $ — $ (2) $ — $ — $ (49) (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $815 million at June 30, 2019, and $861 million at December 31, 2018, which includes a fair value derivative adjustment of $403 million and $452 million, respectively.
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	The following tables present a reconciliation of the beginning and ending balances of financial instruments measured at fair value using significant unobservable inputs (Level 3): Assets Liabilities Three Months Ended Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 465 $ 1,502 $ 60 $ 67 $ 1 $ 10 $ 1,141 Transfers out of Level 3 (13) (71) — — — — — Change in Net Unrealized Gains (Losses) in OCI (6) 1 — (1) — — — Net Realized Gains/Losses (1) (13) — (1) — — (213) Purchases 67 83 — 8 1 — — Sales (16) (48) — (9) — — — Settlements (27) (85) — — — — — Balance – end of period $ 469 $ 1,369 $ 60 $ 64 $ 2 $ 10 $ 928 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ 5 $ — $ 1 $ — $ — $ (213) Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date $ (5) $ 7 $ — $ — $ — $ — $ — (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $1,372 million at June 30, 2020, and $1,591 million at March 31, 2020, which includes a fair value derivative adjustment of $928 million and $1,141 million, respectively. Assets Liabilities Three Months Ended Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 360 $ 1,342 $ 78 $ 55 $ — $ 11 $ 338 Transfers into Level 3 — 10 — — — — — Change in Net Unrealized Gains/Losses in OCI, including foreign exchange — 1 — 1 — — — Net Realized Gains/Losses — (1) — (1) — — 65 Purchases 43 121 — 5 4 — — Sales (14) (36) (1) (4) — — — Settlements (18) (78) (1) — — — — Balance – end of period $ 371 $ 1,359 $ 76 $ 56 $ 4 $ 11 $ 403 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ (1) $ — $ (1) $ — $ — $ 65 (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $815 million at June 30, 2019, and $741 million at March 31, 2019, which includes a fair value derivative adjustment of $403 million and $338 million, respectively. Assets Liabilities Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Six Months Ended Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 449 $ 1,451 $ 60 $ 69 $ 6 $ 10 $ 456 Transfers into Level 3 — 91 — — — — — Transfers out of Level 3 (16) (72) — — — — — Change in Net Unrealized Gains (Losses) in OCI, including foreign exchange (20) (44) — — — — — Net Realized Gains/Losses (3) (26) — (3) — — 472 Purchases 149 222 — 11 2 — — Sales (62) (67) — (13) — — — Settlements (28) (186) — — (6) — — Balance – end of period $ 469 $ 1,369 $ 60 $ 64 $ 2 $ 10 $ 928 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ (9) $ — $ (1) $ — $ — $ 472 Change in Net Unrealized Gains/Losses included in OCI at the Balance sheet date $ (20) $ (37) $ — $ — $ — $ — $ — (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $1,372 million at June 30, 2020, and $897 million at December 31, 2019, which includes a fair value derivative adjustment of $928 million and $456 million, respectively. Assets Liabilities Available-for-Sale Debt Securities Equity Short-term investments Other GLB (1) Six Months Ended Non-U.S. Corporate and asset-backed securities MBS Balance – beginning of period $ 345 $ 1,299 $ 61 $ 57 $ 1 $ 11 $ 452 Transfers into Level 3 3 15 — — — — — Transfers out of Level 3 (15) — — — — — — Change in Net Unrealized Gains/Losses in OCI, including foreign exchange 6 5 — 2 — — — Net Realized Gains/Losses (1) — — (3) — — (49) Purchases 96 249 18 14 4 — — Sales (19) (73) (1) (14) — — — Settlements (44) (136) (2) — (1) — — Balance – end of period $ 371 $ 1,359 $ 76 $ 56 $ 4 $ 11 $ 403 Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date $ — $ (1) $ — $ (2) $ — $ — $ (49) (1) Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $815 million at June 30, 2019, and $861 million at December 31, 2018, which includes a fair value derivative adjustment of $403 million and $452 million, respectively.
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: June 30, 2020 Fair Value Net Carrying (in millions of U.S. dollars) Level 1 Level 2 Level 3 Total Assets: Fixed maturities held to maturity U.S. Treasury / Agency $ 1,257 $ 58 $ — $ 1,315 $ 1,242 Non-U.S. — 1,370 — 1,370 1,270 Corporate and asset-backed securities — 2,428 — 2,428 2,191 Mortgage-backed securities — 2,331 — 2,331 2,188 Municipal — 5,176 — 5,176 4,954 Total assets $ 1,257 $ 11,363 $ — $ 12,620 $ 11,845 Liabilities: Repurchase agreements $ — $ 1,409 $ — $ 1,409 $ 1,409 Short-term debt — 1,309 — 1,309 1,300 Long-term debt — 15,650 — 15,650 13,656 Trust preferred securities — 453 — 453 308 Total liabilities $ — $ 18,821 $ — $ 18,821 $ 16,673 December 31, 2019 Fair Value Carrying (in millions of U.S. dollars) Level 1 Level 2 Level 3 Total Assets: Fixed maturities held to maturity U.S. Treasury / Agency $ 1,292 $ 55 $ — $ 1,347 $ 1,318 Non-U.S. — 1,485 — 1,485 1,423 Corporate and asset-backed securities — 2,436 32 2,468 2,349 Mortgage-backed securities — 2,396 — 2,396 2,331 Municipal — 5,309 — 5,309 5,160 Total assets $ 1,292 $ 11,681 $ 32 $ 13,005 $ 12,581 Liabilities: Repurchase agreements $ — $ 1,416 $ — $ 1,416 $ 1,416 Short-term debt — 1,307 — 1,307 1,299 Long-term debt — 15,048 — 15,048 13,559 Trust preferred securities — 467 — 467 308 Total liabilities $ — $ 18,238 $ — $ 18,238 $ 16,582

Reinsurance (Tables)

Reinsurance (Tables)	6 Months Ended
	Jun. 30, 2020
Credit Loss [Abstract]
schedule of reinsurance recoverable on ceded insurance	June 30, 2020 December 31, 2019 (in millions of U.S. dollars) Net Reinsurance Recoverable (1) Valuation allowance Net Reinsurance Recoverable (1) Valuation allowance Reinsurance recoverable on unpaid losses and loss expenses $ 14,361 $ 240 $ 14,181 $ 240 Reinsurance recoverable on paid losses and loss expenses 846 63 1,000 76 Reinsurance recoverable on losses and loss expenses $ 15,207 $ 303 $ 15,181 $ 316 Reinsurance recoverable on policy benefits $ 197 $ 4 $ 197 $ 4 (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: Six Months Ended June 30 (in millions of U.S. dollars) 2020 Reinsurance recoverable Valuation allowance for uncollectible reinsurance - beginning of period $ 316 Provision for uncollectible reinsurance 5 Write-offs charged against the valuation allowance (19) Foreign exchange revaluation 1 Valuation allowance for uncollectible reinsurance - end of period $ 303

Unpaid losses and loss expens_2

Unpaid losses and loss expenses Unpaid losses and loss expenses (Tables)	6 Months Ended
	Jun. 30, 2020
Liability for Claims and Claims Adjustment Expense [Abstract]
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block]	The following table presents a reconciliation of beginning and ending Unpaid losses and loss expenses: Six Months Ended June 30 (in millions of U.S. dollars) 2020 2019 Gross unpaid losses and loss expenses – beginning of period $ 62,690 $ 62,960 Reinsurance recoverable on unpaid losses - beginning of period (1) (14,181) (14,689) Net unpaid losses and loss expenses – beginning of period 48,509 48,271 Net losses and loss expenses incurred in respect of losses occurring in: Current year 11,111 9,224 Prior years (2) (49) (411) Total 11,062 8,813 Net losses and loss expenses paid in respect of losses occurring in: Current year 2,263 2,288 Prior years 5,842 5,823 Total 8,105 8,111 Foreign currency revaluation and other (128) (1) Net unpaid losses and loss expenses – end of period 51,338 48,972 Reinsurance recoverable on unpaid losses (1) 14,361 14,233 Gross unpaid losses and loss expenses – end of period $ 65,699 $ 63,205 (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 $6 million and $19 million for the six months ended June 30, 2020 and 2019, respectively.
Prior Period Development, by Segment [Table Text Block]	The following table summarizes (favorable) and adverse PPD by segment. Three Months Ended June 30 Six Months Ended June 30 (in millions of U.S. dollars) Long-tail Short-tail Total Long-tail Short-tail Total 2020 North America Commercial P&C Insurance $ (141) $ (5) $ (146) $ (184) $ (67) $ (251) North America Personal P&C Insurance — (1) (1) — — — North America Agricultural Insurance — — — — (14) (14) Overseas General Insurance (1) (35) (36) (1) (39) (40) Global Reinsurance (19) 3 (16) (19) (4) (23) Corporate 274 — 274 285 — 285 Total $ 113 $ (38) $ 75 $ 81 $ (124) $ (43) 2019 North America Commercial P&C Insurance $ (206) $ 21 $ (185) $ (271) $ (45) $ (316) North America Personal P&C Insurance — (16) (16) — (26) (26) North America Agricultural Insurance — — — — (61) (61) Overseas General Insurance — (20) (20) — (24) (24) Global Reinsurance (33) 33 — (34) 26 (8) Corporate 33 — 33 43 — 43 Total $ (206) $ 18 $ (188) $ (262) $ (130) $ (392)

Commitments, contingencies, a_2

Commitments, contingencies, and guarantees (Tables)	6 Months Ended
	Jun. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Balance Sheet Locations, Fair Values In An Asset Or (Liability) Position, And Notional Values/Payment Provisions Of Derivative Instruments	The following table presents the balance sheet locations, fair values of derivative instruments in an asset or (liability) position, and notional values/payment provisions of our derivative instruments: June 30, 2020 December 31, 2019 Consolidated Fair Value Notional Fair Value Notional (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) $ 16 $ (85) $ 2,462 $ 11 $ (78) $ 2,579 Options/Futures contracts on notes, bonds, and equities OA / (AP) 3 (11) 1,398 13 (15) 1,615 Convertible securities (1) FM AFS / ES 8 — 10 4 — 5 $ 27 $ (96) $ 3,870 $ 28 $ (93) $ 4,199 Other derivative instruments: Futures contracts on equities (2) OA / (AP) $ — $ — $ 598 $ — $ (13) $ 613 Other OA / (AP) 1 — 97 2 — 63 $ 1 $ — $ 695 $ 2 $ (13) $ 676 GLB (3) (AP) / (FPB) $ — $ (1,372) $ 2,196 $ — $ (897) $ 1,510 (1) Includes fair value of embedded derivatives. (2) Related to GMDB and GLB book of business. (3) Includes both future policy benefits reserves of $444 million and $441 million and fair value derivative adjustment of $928 million and $456 million at June 30, 2020 and December 31, 2019, respectively. Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.
Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations	The following table presents net realized gains (losses) related to derivative instrument activity in the Consolidated statements of operations: Three Months Ended Six Months Ended June 30 June 30 (in millions of U.S. dollars) 2020 2019 2020 2019 Investment and embedded derivative instruments: Foreign currency forward contracts $ 10 $ (22) $ 53 $ (37) Interest rate swaps — (135) — (215) All other futures contracts, options, and equities 3 (25) (24) (61) Convertible securities (1) 1 1 — 2 Total investment and embedded derivative instruments $ 14 $ (181) $ 29 $ (311) GLB and other derivative instruments: GLB (2) $ 213 $ (65) $ (472) $ 49 Futures contracts on equities (3) (103) (20) 22 (83) Other (1) 7 (3) 6 Total GLB and other derivative instruments $ 109 $ (78) $ (453) $ (28) $ 123 $ (259) $ (424) $ (339) (1) Includes embedded derivatives. (2) Excludes foreign exchange gains (losses) related to GLB. (3) 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 June 30, 2020 December 31, 2019 (in millions of U.S. dollars) Overnight and Continuous Collateral held under securities lending agreements: Cash $ 665 $ 346 U.S. Treasury / Agency 52 6 Non-U.S. 1,059 595 Corporate and asset-backed securities 20 5 Mortgage-backed securities — 18 Equity securities 36 24 $ 1,832 $ 994 Gross amount of recognized liability for securities lending payable $ 1,832 $ 994 The following table presents the carrying value of collateral pledged under repurchase agreements by investment category and remaining contractual maturity of the underlying agreements: Remaining contractual maturity June 30, 2020 December 31, 2019 Greater than Total Up to 30 Days 30-90 Days Greater than Total (in millions of U.S. dollars) Collateral pledged under repurchase agreements: Cash $ 1 $ 1 $ 2 $ — $ — $ 2 U.S. Treasury / Agency 109 109 107 — — 107 Mortgage-backed securities 1,350 1,350 399 476 480 1,355 $ 1,460 $ 1,460 $ 508 $ 476 $ 480 $ 1,464 Gross amount of recognized liabilities for repurchase agreements $ 1,409 $ 1,416 Difference (1) $ 51 $ 48 (1) Per the repurchase agreements, the amount of collateral posted is required to exceed the amount of gross liability.

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2020
Stockholders' Equity Note [Abstract]
Dividends Declared	The following table presents dividend distributions per Common Share in Swiss francs (CHF) and U.S. dollars (USD): Three Months Ended Six Months Ended June 30 June 30 2020 2019 2020 2019 CHF USD CHF USD CHF USD CHF USD Total dividend distributions per common share 0.75 $ 0.78 0.75 $ 0.75 1.47 $ 1.53 1.47 $ 1.48
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 Six Months Ended June 30 June 30 (in millions of U.S. dollars, except share data) 2020 2019 2020 2019 Number of shares repurchased — 2,584,466 2,266,150 5,338,220 Cost of shares repurchased $ — $ 376 $ 326 $ 743 Repurchase authorization remaining at end of period $ 1,124 $ 736 $ 1,124 $ 736

Postretirement benefits (Tables

Postretirement benefits (Tables)	6 Months Ended
	Jun. 30, 2020
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 (loss) in the Consolidated statements of operations were as follows: Pension Benefit Plans Other Postretirement 2020 2019 2020 2019 Three Months Ended June 30 U.S. Plans Non-U.S. Plans U.S. Plans Non-U.S. Plans (in millions of U.S. dollars) Service cost $ — $ 1 $ 13 $ 2 $ — $ — Non-service cost: Interest cost 25 5 29 7 — 1 Expected return on plan assets (56) (11) (48) (11) (1) (1) Amortization of net actuarial loss — 1 — 1 — — Amortization of prior service cost — — — — (20) (20) Settlements 1 — — — — — Total non-service (benefit) cost (30) (5) (19) (3) (21) (20) Net periodic (benefit) cost $ (30) $ (4) $ (6) $ (1) $ (21) $ (20) Pension Benefit Plans Other Postretirement 2020 2019 2020 2019 Six Months Ended June 30 U.S. Plans Non-U.S. Plans U.S. Plans Non-U.S. Plans (in millions of U.S. dollars) Service cost $ — $ 2 $ 25 $ 5 $ — $ — Non-service cost: Interest cost 50 11 59 14 1 2 Expected return on plan assets (112) (21) (95) (22) (2) (2) Amortization of net actuarial loss — 1 — 1 — — Amortization of prior service cost — — — — (40) (40) Settlements 2 — — — — — Total non-service (benefit) cost (60) (9) (36) (7) (41) (40) Net periodic (benefit) cost $ (60) $ (7) $ (11) $ (2) $ (41) $ (40) The line items in which the service and non-service cost components of net periodic (benefit) cost are included in the Consolidated statements of operations were as follows: Pension Benefit Plans Other Postretirement Benefit Plans Three Months Ended June 30 2020 2019 2020 2019 (in millions of U.S. dollars) Service cost: Losses and loss expenses $ — $ 1 $ — $ — Administrative expenses 1 14 — — Total service cost 1 15 — — Non-service cost: Losses and loss expenses (3) (2) (2) (2) Administrative expenses (32) (20) (19) (18) Total non-service (benefit) cost (35) (22) (21) (20) Net periodic (benefit) cost $ (34) $ (7) $ (21) $ (20) Pension Benefit Plans Other Postretirement Benefit Plans Six Months Ended June 30 2020 2019 2020 2019 (in millions of U.S. dollars) Service cost: Losses and loss expenses $ — $ 3 $ — $ — Administrative expenses 2 27 — — Total service cost 2 30 — — Non-service cost: Losses and loss expenses (6) (4) (4) (4) Administrative expenses (63) (39) (37) (36) Total non-service (benefit) cost (69) (43) (41) (40) Net periodic (benefit) cost $ (67) $ (13) $ (41) $ (40)

Segment information (Tables)

Segment information (Tables)	6 Months Ended
	Jun. 30, 2020
Segment Reporting [Abstract]
Operations By Segment	The following tables present the Statement of Operations by segment: For the Three Months Ended North America Commercial P&C Insurance North America Personal P&C Insurance North America Agricultural Insurance Overseas General Insurance Global Life Insurance Corporate Chubb Net premiums written $ 3,720 $ 1,327 $ 461 $ 2,021 $ 207 $ 619 $ — $ 8,355 Net premiums earned 3,595 1,192 376 2,194 163 608 — 8,128 Losses and loss expenses 3,498 762 312 1,485 73 171 276 6,577 Policy benefits — — — — — 223 — 223 Policy acquisition costs 471 231 29 624 42 196 — 1,593 Administrative expenses 249 66 3 241 9 82 77 727 Underwriting income (loss) (623) 133 32 (156) 39 (64) (353) (992) Net investment income (loss) 507 65 7 124 51 95 (22) 827 Other (income) expense 4 1 1 8 (8) (57) 109 58 Amortization expense of purchased intangibles — 3 6 11 — 1 51 72 Segment income (loss) $ (120) $ 194 $ 32 $ (51) $ 98 $ 87 $ (535) $ (295) Net realized gains (losses) 30 30 Interest expense 128 128 Income tax benefit (62) (62) Net loss $ (571) $ (331) For the Three Months Ended North America Commercial P&C Insurance North America Personal P&C Insurance North America Agricultural Insurance Overseas General Insurance Global Life Insurance Corporate Chubb Net premiums written $ 3,534 $ 1,309 $ 466 $ 2,258 $ 197 $ 579 $ — $ 8,343 Net premiums earned 3,390 1,168 378 2,225 159 571 — 7,891 Losses and loss expenses 2,214 747 316 1,125 90 189 34 4,715 Policy benefits — — — — — 161 — 161 Policy acquisition costs 459 237 27 629 42 150 — 1,544 Administrative expenses 259 71 4 265 7 78 74 758 Underwriting income (loss) 458 113 31 206 20 (7) (108) 713 Net investment income (loss) 521 64 4 151 55 97 (33) 859 Other (income) expense 2 1 1 3 (15) (7) (215) (230) Amortization expense of purchased intangibles — 3 7 12 — 1 54 77 Segment income $ 977 $ 173 $ 27 $ 342 $ 90 $ 96 $ 20 $ 1,725 Net realized gains (losses) including OTTI (223) (223) Interest expense 140 140 Chubb integration expenses 4 4 Income tax expense 208 208 Net income (loss) $ (555) $ 1,150 For the Six Months Ended North America Commercial P&C Insurance North America Personal P&C Insurance North America Agricultural Insurance Overseas General Insurance Global Reinsurance Life Insurance Corporate Chubb Consolidated Net premiums written $ 6,972 $ 2,434 $ 618 $ 4,619 $ 425 $ 1,264 $ — $ 16,332 Net premiums earned 6,971 2,392 470 4,501 349 1,239 — 15,922 Losses and loss expenses 5,679 1,445 375 2,743 160 373 287 11,062 Policy benefits — — — — — 352 — 352 Policy acquisition costs 963 476 40 1,266 87 376 — 3,208 Administrative expenses 508 134 7 499 19 158 143 1,468 Underwriting income (loss) (179) 337 48 (7) 83 (20) (430) (168) Net investment income (loss) 1,023 131 16 269 105 190 (46) 1,688 Other (income) expense 1 3 1 12 (23) (13) 132 113 Amortization expense of purchased intangibles — 6 13 23 — 2 101 145 Segment income (loss) $ 843 $ 459 $ 50 $ 227 $ 211 $ 181 $ (709) $ 1,262 Net realized gains (losses) (928) (928) Interest expense 260 260 Income tax expense 153 153 Net loss $ (2,050) $ (79) For the Six Months Ended North America Commercial P&C Insurance North America Personal P&C Insurance North America Agricultural Insurance Overseas General Insurance Global Reinsurance Life Insurance Corporate Chubb Consolidated Net premiums written $ 6,485 $ 2,365 $ 596 $ 4,653 $ 399 $ 1,158 $ — $ 15,656 Net premiums earned 6,475 2,322 433 4,339 327 1,132 — 15,028 Losses and loss expenses 4,187 1,504 289 2,231 166 391 45 8,813 Policy benefits — — — — — 357 — 357 Policy acquisition costs 918 468 34 1,225 85 278 — 3,008 Administrative expenses 499 139 5 514 17 157 137 1,468 Underwriting income (loss) 871 211 105 369 59 (51) (182) 1,382 Net investment income (loss) 1,031 128 14 295 111 186 (70) 1,695 Other (income) expense (3) 1 1 7 (24) (47) (204) (269) Amortization expense of purchased intangibles — 6 14 23 — 1 109 153 Segment income (loss) $ 1,905 $ 332 $ 104 $ 634 $ 194 $ 181 $ (157) $ 3,193 Net realized gains (losses) including OTTI (320) (320) Interest expense 280 280 Chubb integration expenses 7 7 Income tax expense 396 396 Net income (loss) $ (1,160) $ 2,190

Earnings per share (Tables)

Earnings per share (Tables)	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Schedule Of Earnings Per Share, Basic And Diluted	Three Months Ended Six Months Ended June 30 June 30 (in millions of U.S. dollars, except share and per share data) 2020 2019 2020 2019 Numerator: Net income (loss) $ (331) $ 1,150 $ (79) $ 2,190 Denominator: Denominator for basic earnings per share: Weighted-average shares outstanding 451,402,807 457,224,455 451,635,733 458,010,447 Denominator for diluted earnings per share: Share-based compensation plans (1) — 2,945,237 — 2,863,109 Weighted-average shares outstanding and assumed conversions 451,402,807 460,169,692 451,635,733 460,873,556 Basic earnings (loss) per share $ (0.73) $ 2.52 $ (0.17) $ 4.78 Diluted earnings (loss) per share $ (0.73) $ 2.50 $ (0.17) $ 4.75 Potential anti-dilutive share conversions 8,378,447 2,660,925 6,583,319 5,037,959

Information provided in conne_2

Information provided in connection with outstanding debt of subsidiaries (Tables)	6 Months Ended
	Jun. 30, 2020
Table Text Block Supplement [Abstract]
Condensed Consolidating Balance Sheet	Condensed Consolidating Balance Sheet at June 30, 2020 (in millions of U.S. dollars) Chubb Chubb INA Other Chubb Consolidating Chubb Limited Assets Investments $ — $ 195 $ 110,682 $ — $ 110,877 Cash (1) 1 — 2,624 (1,068) 1,557 Restricted cash — — 152 — 152 Insurance and reinsurance balances receivable — — 13,637 (2,784) 10,853 Reinsurance recoverable on losses and loss expenses — — 24,804 (9,597) 15,207 Reinsurance recoverable on policy benefits — — 292 (95) 197 Value of business acquired — — 290 — 290 Goodwill and other intangible assets — — 21,093 — 21,093 Investments in subsidiaries 52,339 52,752 — (105,091) — Due from subsidiaries and affiliates, net 3,636 — — (3,636) — Other assets 8 336 22,858 (1,954) 21,248 Total assets $ 55,984 $ 53,283 $ 196,432 $ (124,225) $ 181,474 Liabilities Unpaid losses and loss expenses $ — $ — $ 75,013 $ (9,314) $ 65,699 Unearned premiums — — 18,301 (1,220) 17,081 Future policy benefits — — 5,990 (95) 5,895 Due to subsidiaries and affiliates, net — 3,365 271 (3,636) — Affiliated notional cash pooling programs (1) 882 186 — (1,068) — Repurchase agreements — — 1,409 — 1,409 Short-term debt — 1,300 — — 1,300 Long-term debt — 13,656 — — 13,656 Trust preferred securities — 308 — — 308 Other liabilities 342 1,415 23,410 (3,801) 21,366 Total liabilities 1,224 20,230 124,394 (19,134) 126,714 Total shareholders’ equity 54,760 33,053 72,038 (105,091) 54,760 Total liabilities and shareholders’ equity $ 55,984 $ 53,283 $ 196,432 $ (124,225) $ 181,474 (1) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive. Condensed Consolidating Balance Sheet at December 31, 2019 (in millions of U.S. dollars) Chubb Chubb INA Other Chubb Consolidating Chubb Limited Assets Investments $ — $ 1,013 $ 108,221 $ — $ 109,234 Cash (1) 2 442 1,093 — 1,537 Restricted cash — — 109 — 109 Insurance and reinsurance balances receivable — — 12,920 (2,563) 10,357 Reinsurance recoverable on losses and loss expenses — — 24,780 (9,599) 15,181 Reinsurance recoverable on policy benefits — — 292 (95) 197 Value of business acquired — — 306 — 306 Goodwill and other intangible assets — — 21,359 — 21,359 Investments in subsidiaries 50,853 52,076 — (102,929) — Due from subsidiaries and affiliates, net 4,776 — — (4,776) — Other assets 12 408 20,072 (1,829) 18,663 Total assets $ 55,643 $ 53,939 $ 189,152 $ (121,791) $ 176,943 Liabilities Unpaid losses and loss expenses $ — $ — $ 71,916 $ (9,226) $ 62,690 Unearned premiums — — 17,978 (1,207) 16,771 Future policy benefits — — 5,909 (95) 5,814 Due to subsidiaries and affiliates, net — 4,446 330 (4,776) — Repurchase agreements — — 1,416 — 1,416 Short-term debt — 1,298 1 — 1,299 Long-term debt — 13,559 — — 13,559 Trust preferred securities — 308 — — 308 Other liabilities 312 1,649 21,352 (3,558) 19,755 Total liabilities 312 21,260 118,902 (18,862) 121,612 Total shareholders’ equity 55,331 32,679 70,250 (102,929) 55,331 Total liabilities and shareholders’ equity $ 55,643 $ 53,939 $ 189,152 $ (121,791) $ 176,943
Condensed Consolidating Statement Of Operations and Comprehensive Income	Condensed Consolidating Statements of Operations and Comprehensive Income (Loss) For the Three Months Ended June 30, 2020 Chubb Chubb INA Other Chubb Consolidating Chubb (in millions of U.S. dollars) Net premiums written $ — $ — $ 8,355 $ — $ 8,355 Net premiums earned — — 8,128 — 8,128 Net investment income — 1 826 — 827 Equity in earnings of subsidiaries (366) (271) — 637 — Net realized gains (losses) 23 (192) 199 — 30 Losses and loss expenses — — 6,577 — 6,577 Policy benefits — — 223 — 223 Policy acquisition costs and administrative expenses 21 (30) 2,329 — 2,320 Interest (income) expense (35) 149 14 — 128 Other (income) expense (8) (5) 71 — 58 Amortization of purchased intangibles — — 72 — 72 Income tax expense (benefit) 10 (66) (6) — (62) Net loss $ (331) $ (510) $ (127) $ 637 $ (331) Comprehensive income $ 2,860 $ 1,872 $ 3,078 $ (4,950) $ 2,860 Condensed Consolidating Statements of Operations and Comprehensive Income For the Three Months Ended June 30, 2019 Chubb Chubb INA Other Chubb Consolidating Chubb (in millions of U.S. dollars) Net premiums written $ — $ — $ 8,343 $ — $ 8,343 Net premiums earned — — 7,891 — 7,891 Net investment income 1 (6) 864 — 859 Equity in earnings of subsidiaries 1,104 762 — (1,866) — Net realized gains (losses) including OTTI 4 (21) (206) — (223) Losses and loss expenses — — 4,715 — 4,715 Policy benefits — — 161 — 161 Policy acquisition costs and administrative expenses 22 (5) 2,285 — 2,302 Interest (income) expense (62) 180 22 — 140 Other (income) expense (6) 1 (225) — (230) Amortization of purchased intangibles — — 77 — 77 Chubb integration expenses — — 4 — 4 Income tax expense (benefit) 5 (45) 248 — 208 Net income $ 1,150 $ 604 $ 1,262 $ (1,866) $ 1,150 Comprehensive income $ 2,059 $ 1,397 $ 2,181 $ (3,578) $ 2,059 Condensed Consolidating Statements of Operations and Comprehensive Income For the Six Months Ended June 30, 2020 Chubb Limited (Parent Guarantor) Chubb INA Holdings Inc. (Subsidiary Issuer) Other Chubb Limited Subsidiaries Consolidating Adjustments and Eliminations Chubb Limited Consolidated (in millions of U.S. dollars) Net premiums written $ — $ — $ 16,332 $ — $ 16,332 Net premiums earned — — 15,922 — 15,922 Net investment income (2) 5 1,685 — 1,688 Equity in earnings of subsidiaries (110) 322 — (212) — Net realized gains (losses) 2 (79) (851) — (928) Losses and loss expenses — — 11,062 — 11,062 Policy benefits — — 352 — 352 Policy acquisition costs and administrative expenses 45 (68) 4,699 — 4,676 Interest (income) expense (69) 297 32 — 260 Other (income) expense (17) 3 127 — 113 Amortization of purchased intangibles — — 145 — 145 Income tax expense (benefit) 10 (59) 202 — 153 Net income (loss) $ (79) $ 75 $ 137 $ (212) $ (79) Comprehensive income $ 400 $ 672 $ 660 $ (1,332) $ 400 Condensed Consolidating Statements of Operations and Comprehensive Income For the Six Months Ended June 30, 2019 Chubb Limited (Parent Guarantor) Chubb INA Holdings Inc. (Subsidiary Issuer) Other Chubb Limited Subsidiaries Consolidating Adjustments and Eliminations Chubb Limited Consolidated (in millions of U.S. dollars) Net premiums written $ — $ — $ 15,656 $ — $ 15,656 Net premiums earned — — 15,028 — 15,028 Net investment income 2 (10) 1,703 — 1,695 Equity in earnings of subsidiaries 2,094 1,521 — (3,615) — Net realized gains (losses) including OTTI 5 (34) (291) — (320) Losses and loss expenses — — 8,813 — 8,813 Policy benefits — — 357 — 357 Policy acquisition costs and administrative expenses 42 (20) 4,454 — 4,476 Interest (income) expense (128) 365 43 — 280 Other (income) expense (12) 4 (261) — (269) Amortization of purchased intangibles — — 153 — 153 Chubb integration expenses — 2 5 — 7 Income tax expense (benefit) 9 (87) 474 — 396 Net income $ 2,190 $ 1,213 $ 2,402 $ (3,615) $ 2,190 Comprehensive income $ 4,777 $ 3,338 $ 4,969 $ (8,307) $ 4,777
Condensed Consolidating Statement of Cash Flows	Condensed Consolidating Statement of Cash Flows Six Months Ended June 30, 2020 Chubb Chubb INA Other Chubb Consolidating Chubb (in millions of U.S. dollars) Net cash flows from (used for) operating activities $ 181 $ (307) $ 3,933 $ (110) $ 3,697 Cash flows from investing activities Purchases of fixed maturities available for sale — (13) (13,045) — (13,058) Purchases of fixed maturities held to maturity — — (42) — (42) Purchases of equity securities — — (2,824) — (2,824) Sales of fixed maturities available for sale — 7 7,727 — 7,734 Sales of equity securities — — 1,353 — 1,353 Maturities and redemptions of fixed maturities available for sale — 29 5,191 — 5,220 Maturities and redemptions of fixed maturities held to maturity — — 642 — 642 Net change in short-term investments — 761 (588) — 173 Net derivative instruments settlements — 69 (87) — (18) Private equity contributions — — (546) — (546) Private equity distributions — — 443 — 443 Deposit paid on share acquisition — — (1,550) — (1,550) Capital contribution (1,200) — — 1,200 — Other (1) (3) (217) — (221) Net cash flows from (used for) investing activities (1,201) 850 (3,543) 1,200 (2,694) Cash flows from financing activities Dividends paid on Common Shares (678) — — — (678) Common Shares repurchased (333) — — — (333) Proceeds from issuance of repurchase agreements — — 1,402 — 1,402 Repayment of repurchase agreements — — (1,402) — (1,402) Proceeds from share-based compensation plans — — 74 — 74 Dividend to parent company — — (110) 110 — Advances (to) from affiliates 1,149 (1,168) 19 — — Capital contribution — — 1,200 (1,200) — Net proceeds from (payments to) affiliated notional cash pooling programs (1) 882 186 — (1,068) — Policyholder contract deposits — — 215 — 215 Policyholder contract withdrawals — — (173) — (173) Other — (3) — — (3) Net cash flows from (used for) financing activities 1,020 (985) 1,225 (2,158) (898) Effect of foreign currency rate changes on cash and restricted cash (1) — (41) — (42) Net increase (decrease) in cash and restricted cash (1) (442) 1,574 (1,068) 63 Cash and restricted cash – beginning of period (1) 2 442 1,202 — 1,646 Cash and restricted cash – end of period (1) $ 1 $ — $ 2,776 $ (1,068) $ 1,709 (1) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020 and December 31, 2019, the cash balance of one or more entities was negative; however, the overall Pool balances were positive. Condensed Consolidating Statement of Cash Flows Six Months Ended June 30, 2019 Chubb Chubb INA Other Chubb Consolidating Chubb (in millions of U.S. dollars) Net cash flows from operating activities $ 323 $ 1,302 $ 2,943 $ (1,860) $ 2,708 Cash flows from investing activities Purchases of fixed maturities available for sale — (5) (12,561) — (12,566) Purchases of fixed maturities held to maturity — — (73) — (73) Purchases of equity securities — — (147) — (147) Sales of fixed maturities available for sale — — 7,838 — 7,838 Sales of equity securities — — 266 — 266 Maturities and redemptions of fixed maturities available for sale — 16 3,947 — 3,963 Maturities and redemptions of fixed maturities held to maturity — — 598 — 598 Net change in short-term investments — (11) (752) — (763) Net derivative instruments settlements — (35) (501) — (536) Private equity contributions — — (920) — (920) Private equity distributions — — 780 — 780 Capital contribution (600) (110) — 710 — Other — (12) (715) — (727) Net cash flows used for investing activities (600) (157) (2,240) 710 (2,287) Cash flows from financing activities Dividends paid on Common Shares (671) — — — (671) Common Shares repurchased — — (741) — (741) Proceeds from issuance of long-term debt — 1,289 — — 1,289 Repayment of long-term debt — (500) — — (500) Proceeds from issuance of repurchase agreements — — 1,984 — 1,984 Repayment of repurchase agreements — — (1,986) — (1,986) Proceeds from share-based compensation plans — — 95 — 95 Dividend to parent company — — (1,860) 1,860 — Advances (to) from affiliates 801 (1,498) 697 — — Capital contribution — — 710 (710) — Net proceeds from (payments to) affiliated notional cash pooling programs (1) 142 (437) — 295 — Policyholder contract deposits — — 237 — 237 Policyholder contract withdrawals — — (138) — (138) Other — — — — — Net cash flows from (used for) financing activities 272 (1,146) (1,002) 1,445 (431) Effect of foreign currency rate changes on cash and restricted cash 5 — 33 — 38 Net increase (decrease) in cash and restricted cash — (1) (266) 295 28 Cash and restricted cash – beginning of period (1) 1 2 1,989 (652) 1,340 Cash and restricted cash – end of period (1) $ 1 $ 1 $ 1,723 $ (357) $ 1,368 (1) Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2019 and December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

General Schedule of Cash and Ca

General Schedule of Cash and Cash Equivalent (Details) - USD ($) $ in Millions	Jun. 30, 2020		Dec. 31, 2019		Jun. 30, 2019	[4]	Dec. 31, 2018	[4]
Cash and Cash Equivalents [Line Items]
Cash	$ 1,557	[1]	$ 1,537	[2]
Restricted cash	152		109
Total cash and restricted cash shown in the Consolidated statement of cash flows	$ 1,709	[3]	$ 1,646	[3]	$ 1,368		$ 1,340
[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to the 2019 Form 10-K for additional information.
[3]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020 and December 31, 2019, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[4]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2019 and December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

General Goodwill (Details)

General Goodwill (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Period Increase (Decrease)	$ (112)

General Adoption of New Account

General Adoption of New Accounting Pronouncements (Details) - USD ($) $ in Millions	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	$ (54,760)		$ (55,331)	$ (53,802)
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, Net of Tax	$ (35,991)	$ (36,322)	(36,070)	$ (33,878)	$ (32,728)	$ (31,688)
Retained Earnings [Member] | Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect on Retained Earnings, before Tax			79
Cumulative Effect on Retained Earnings, Net of Tax		$ 0	$ 72			$ 12

Acquisitions Acquisitions (narr

Acquisitions Acquisitions (narrative) (Details) - USD ($) $ in Millions	Jul. 13, 2020	Jun. 30, 2020	Jun. 30, 2019
Business Acquisition [Line Items]
Payments for Other Deposits		$ 1,550	$ 0
CHINA | Huatai Group [Member]
Business Acquisition [Line Items]
Payments for Other Deposits		$ 1,550
CHINA | Huatai Group [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Equity method investment, additional 15.3 ownership percentage obtained	15.30%

Acquisitions Investments (Detai

Acquisitions Investments (Details) - USD ($) $ in Millions	Jul. 13, 2020	Dec. 31, 2021	Jun. 30, 2020
Investment Holdings [Line Items]
Equity Method Investment, Ownership Percentage			100.00%
Huatai Group [Member]
Investment Holdings [Line Items]
Equity Method Investment, Ownership Percentage			30.90%
Huatai Group [Member] | CHINA | Subsequent Event [Member]
Investment Holdings [Line Items]
Equity method investment, additional ownership agreed to be purchased		22.40%
Amount agreed to acquire 22.4 percent of Huatai Group		$ 1,550
Equity method investment, additional 15.3 ownership percentage obtained	15.30%
Portion one of payments to acquire 22.4% of Huatai Group		$ 1,100
Equity method investment, additional 7.1 percentage obtained		7.10%
Portion two of payments to acquire equity method investments		$ 493

Investments (Narrative) (Detail

Investments (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Investments [Line Items]
Equity Method Investment, Ownership Percentage	100.00%	100.00%
Restricted assets in fixed maturities and short-term investments	$ 19,600	$ 19,600	$ 21,000
Restricted assets in cash	152	152	$ 109
Debt Securities, Available-for-sale, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	$ 3	5
Debt Securities, Available-for-sale, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date		5
Debt Securities, Available-for-sale, Purchased with Credit Deterioration, Amount at Par Value		143
Debt Securities, Available-for-sale, Purchased with Credit Deterioration, Amount at Purchase Price		$ 107

Investments Investments (Schedu

Investments Investments (Schedule Of Amortized Cost and Fair Value of Available-for-sale Securities and Related OTTI Recognized in AOCI) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	$ 82,740		$ 82,580
Debt Securities, Available-for-sale, Allowance for Credit Loss	(69)	$ (176)	0
Available for Sale, Gross Unrealized Appreciation	4,638		3,074
Available for Sale, Gross Unrealized Depreciation	(597)		(166)
Available for sale, Fair Value	86,712		85,488
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities			(30)
U.S. Treasury / Agency
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	2,636		3,188
Debt Securities, Available-for-sale, Allowance for Credit Loss	0
Available for Sale, Gross Unrealized Appreciation	239		96
Available for Sale, Gross Unrealized Depreciation	0		(1)
Available for sale, Fair Value	2,875		3,283
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities			0
Non-U.S.
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	23,370		22,670
Debt Securities, Available-for-sale, Allowance for Credit Loss	(17)
Available for Sale, Gross Unrealized Appreciation	1,420		1,099
Available for Sale, Gross Unrealized Depreciation	(166)		(62)
Available for sale, Fair Value	24,607		23,707
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities			(25)
Corporate and asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	32,721		30,689
Debt Securities, Available-for-sale, Allowance for Credit Loss	(52)
Available for Sale, Gross Unrealized Appreciation	1,658		1,180
Available for Sale, Gross Unrealized Depreciation	(410)		(78)
Available for sale, Fair Value	33,917		31,791
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities			(5)
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	17,165		18,712
Debt Securities, Available-for-sale, Allowance for Credit Loss	0
Available for Sale, Gross Unrealized Appreciation	1,051		494
Available for Sale, Gross Unrealized Depreciation	(18)		(14)
Available for sale, Fair Value	18,198		19,192
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities			0
Municipal
Debt Securities, Available-for-sale [Line Items]
Available for sale, at amortized cost	6,848		7,321
Debt Securities, Available-for-sale, Allowance for Credit Loss	0
Available for Sale, Gross Unrealized Appreciation	270		205
Available for Sale, Gross Unrealized Depreciation	(3)		(11)
Available for sale, Fair Value	$ 7,115		7,515
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities			$ 0

Investments (Schedule Of Amorti

Investments (Schedule Of Amortized Cost And Fair Value Of HTM Fixed Maturities And Related OTTI Recognized In Accumulated Other Comprehensive Income) (Detail) - USD ($) $ in Millions	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	$ 11,896		$ 12,581
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(51)	$ (45)	0
Debt securities, held to maturity, net carrying value	11,845
Held-to-maturity, Gross Unrealized Appreciation	791		427
Held-to-maturity, Gross Unrealized Depreciation	(16)		(3)
Held-to-maturity, Fair Value	12,620		13,005
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Held-to-maturity, Debt Securities			0
U.S. Treasury / Agency
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	1,242		1,318
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0
Debt securities, held to maturity, net carrying value	1,242
Held-to-maturity, Gross Unrealized Appreciation	73		29
Held-to-maturity, Gross Unrealized Depreciation	0		0
Held-to-maturity, Fair Value	1,315		1,347
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Held-to-maturity, Debt Securities			0
Non-U.S.
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	1,278		1,423
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(8)
Debt securities, held to maturity, net carrying value	1,270
Held-to-maturity, Gross Unrealized Appreciation	102		62
Held-to-maturity, Gross Unrealized Depreciation	(2)		0
Held-to-maturity, Fair Value	1,370		1,485
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Held-to-maturity, Debt Securities			0
Corporate and asset-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	2,232		2,349
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(41)
Debt securities, held to maturity, net carrying value	2,191
Held-to-maturity, Gross Unrealized Appreciation	247		121
Held-to-maturity, Gross Unrealized Depreciation	(10)		(2)
Held-to-maturity, Fair Value	2,428		2,468
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Held-to-maturity, Debt Securities			0
Mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	2,189		2,331
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(1)
Debt securities, held to maturity, net carrying value	2,188
Held-to-maturity, Gross Unrealized Appreciation	146		65
Held-to-maturity, Gross Unrealized Depreciation	(3)		0
Held-to-maturity, Fair Value	2,331		2,396
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Held-to-maturity, Debt Securities			0
Municipal
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Amortized Cost	4,955		5,160
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(1)
Debt securities, held to maturity, net carrying value	4,954
Held-to-maturity, Gross Unrealized Appreciation	223		150
Held-to-maturity, Gross Unrealized Depreciation	(1)		(1)
Held-to-maturity, Fair Value	$ 5,176		5,309
Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Held-to-maturity, Debt Securities			$ 0

Investments Investments (held-t

Investments Investments (held-to-maturity credit quality indicator) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 11,896	$ 12,581
Fixed Maturities Percent of Total Amortized cost	100.00%
Standard & Poor's, AAA Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 2,583
Fixed Maturities Percent of Total Amortized cost	22.00%
Standard & Poor's, AA Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 6,397
Fixed Maturities Percent of Total Amortized cost	54.00%
Standard & Poor's, A Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 2,302
Fixed Maturities Percent of Total Amortized cost	19.00%
Standard & Poor's, BBB Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 591
Fixed Maturities Percent of Total Amortized cost	5.00%
Standard & Poor's, BB Rating [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 21
Fixed Maturities Percent of Total Amortized cost	0.00%
Other [Member]
Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items]
Debt Securities, Held-to-maturity	$ 2
Fixed Maturities Percent of Total Amortized cost	0.00%

Investments (Schedule Of Fixed

Investments (Schedule Of Fixed Maturities By Contractual Maturity) (Detail) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Available for sale, Due in 1 year or less, Amortized Cost		$ 3,951
Available for sale, Due after 1 year through 5 years, Amortized Cost		27,142
Available for sale, Due after 5 years though 10 years, Amortized Cost		23,901
Available for sale, Due after 10 years, Amortized Cost		8,874
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost		63,868
Available for sale, Mortgage-backed securities, Amortized Cost		18,712
Available for sale, at amortized cost	$ 82,740	82,580
Available for sale, Due in 1 year or less, Fair Value	4,487	3,973
Available for sale, Due after 1 year through 5 years, Fair Value	26,867	27,720
Available for sale, Due after 5 years through 10 years, Fair Value	25,465	24,874
Available for sale, Due after 10 years, Fair Value	11,695	9,729
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	68,514	66,296
Available for sale, Mortgage backed securities, Fair Value	18,198	19,192
Available for sale, Fair Value	86,712	85,488
Debt securities, Held-to-maturity, maturity, allocated and single maturity date, within one year, net carrying value	890
Held to maturity, Due in 1 year or less, Amortized Cost		478
Held to maturity, Due after 1 year through 5 years, Amortized Cost		3,869
Held to maturity, Due after 5 years through 10 years, Amortized Cost		3,756
Held to maturity, Due after 10 years, Amortized Cost		2,147
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Amortized Cost		10,250
Held to maturity, Mortgage backed securities, Amortized Cost		2,331
Held to maturity, Amortized Cost	11,896	12,581
Held to maturity, Due in 1 year or less, Fair Value	902	479
Held-to-maturity, after one through five years, net carrying value	3,505
Held to maturity, Due after 1 year through 5, Fair Value	3,662	3,940
Held-to-maturity, after 5 through 10 years, net carrying value	3,328
Held to maturity, Due after 5 years through 10 years, Fair Value	3,516	3,883
Held-to-maturity, after 10 years, net carrying value	1,934
Held to maturity, Due after 10 years, Fair Value	2,209	2,307
Debt securities, Held-to-maturity, maturity, allocated and single maturity date, net carrying value	9,657
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Fair Value	10,289	10,609
Held-to-maturity, MBS, net carrying value	2,188
Held to maturity, Mortgage backed securities, Fair Value	2,331	2,396
Debt securities, held to maturity, net carrying value	11,845
Held to maturity, Fair Value	$ 12,620	$ 13,005

Investments (Aggregate Fair Val

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	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 12,205	$ 5,563
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(426)	(81)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	748	3,337
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(61)	(88)
Debt Securities, Available-for-sale, Unrealized Loss Position	12,953	8,900
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(487)	(169)
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		234
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(1)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		339
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Debt Securities, Available-for-sale, Unrealized Loss Position		573
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		(1)
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	3,172	1,846
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(117)	(34)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	105	802
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(22)	(28)
Debt Securities, Available-for-sale, Unrealized Loss Position	3,277	2,648
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(139)	(62)
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	7,985	2,121
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(295)	(40)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	551	988
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(35)	(40)
Debt Securities, Available-for-sale, Unrealized Loss Position	8,536	3,109
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(330)	(80)
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	953	1,174
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(13)	(6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	27	932
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2)	(8)
Debt Securities, Available-for-sale, Unrealized Loss Position	980	2,106
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(15)	(14)
Municipal
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	95	188
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1)	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	65	276
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2)	(12)
Debt Securities, Available-for-sale, Unrealized Loss Position	160	464
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (3)	$ (12)

Investments (Net Realized Gains

Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020		Jun. 30, 2019		Jun. 30, 2020		Jun. 30, 2019
Gain (Loss) on Securities [Line Items]
OTTI on fixed maturities, gross	$ 0		$ (14)		$ 0		$ (27)
Debt Securities, Allowance for Credit Loss, Period Increase (Decrease)	29				178
Debt Securities, Available-For-Sale, Credit Impairment Charges Intent to Sell	(31)	[1]	0	[1]	(152)	[1]	0
Foreign exchange gains	(61)		(11)		(129)		2
Gain (Loss) on Derivative	123		(259)		(424)		(339)
Other	(40)		0		(40)		0
Net Realized Gains (Losses)	30		(223)		(928)		(320)
Other than Temporary Impairment Loss, Investments, Portion in Other Comprehensive Loss, before Tax, Portion Attributable to Parent, Available-for-sale Securities	0		1		0		1
Other-than-temporary Impairment Loss, Debt Securities, Portion Recognized in Earnings	0		(13)		0		(26)
Fair Value, Option, Changes in Fair Value, Gain (Loss)	213		(65)		(472)		49
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, before Tax, Portion Attributable to Parent	0		1				1
Investment and embedded derivative instruments
Gain (Loss) on Securities [Line Items]
Gain (Loss) on Derivative	14		(181)		29		(311)
S&P put options and futures
Gain (Loss) on Securities [Line Items]
Gain (Loss) on Derivative	(103)		(20)		22		(83)
Other derivative instruments
Gain (Loss) on Securities [Line Items]
Gain (Loss) on Derivative	(1)		7		(3)		6
Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
OTTI on fixed maturities, gross			14		0		27
Debt Securities, Available-for-sale, Realized Gain, Excluding Other-than-temporary Impairment	68		56		145		83
Debt Securities, Available-for-sale, Realized Loss, Excluding Other-than-temporary Impairment	(174)		(31)		(299)		(89)
Debt Securities, Available-for-sale, Realized Gain (Loss)	(33)		12		(352)		(32)
Debt Securities [Member]
Gain (Loss) on Securities [Line Items]
Other-than-temporary Impairment Loss, Debt Securities, Portion Recognized in Earnings			(13)		0		(26)
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)	148		5		119		63
Other Investments [Member]
Gain (Loss) on Securities [Line Items]
Other investments gain (loss)	(107)		30		(102)		(14)
Accounting Standards Update 2016-13 [Member]
Gain (Loss) on Securities [Line Items]
Debt Securities, Allowance for Credit Loss, Period Increase (Decrease)	$ 104		$ 0		$ (46)		$ 0
[1]	Relates to certain securities we intended to sell and securities written to market entering default.

Investments Schedule of Gains a

Investments Schedule of Gains and Losses on Equity and Other Investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)	$ 148	$ 5	$ 119	$ 63
Less: Net gains (losses) recognized from sales of securities	187	32	163	33
Unrealized gains (losses) recognized for securities still held at reporting date	(39)	(27)	(44)	30
Other Investments [Member]
Gain (Loss) on Securities [Line Items]
Net gains (losses) recognized during the period	(107)	30	(102)	(14)
Less: Net gains (losses) recognized from sales of securities	0	0	0	(2)
Unrealized gains (losses) recognized for securities still held at reporting date	(107)	30	(102)	(12)
Equity securities and other investments [Member]
Gain (Loss) on Securities [Line Items]
Net gains (losses) recognized during the period	41	35	17	49
Less: Net gains (losses) recognized from sales of securities	187	32	163	31
Unrealized gains (losses) recognized for securities still held at reporting date	$ (146)	$ 3	$ (146)	$ 18

Investments Investments (Rollfo

Investments Investments (Rollforward of expected credit-losses, AFS) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 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	$ 69		$ 69		$ 176		$ 0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	3		5
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	29		178
Debt Securities, Available-for-sale, Allowance for Credit Loss, Recovery	(134)		(134)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Writeoff	(5)		(5)
Accounting Standards Update 2016-13 [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss						$ 25
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	$ 104	$ 0	$ (46)	$ 0

Investments Investments (Roll_2

Investments Investments (Rollforward of expected credit losses HTM) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Mar. 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	$ 51	$ 51	$ 45		$ 0
Debt Securities, Held-to-maturity, Allowance for Credit Loss, Period Increase (Decrease)	$ 6	$ 7
Accounting Standards Update 2016-13 [Member]
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss				$ 44

Investments Entities that Calcu

Investments Entities that Calculate Net Asset Value Per Share (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 3,340	$ 3,263
Alternative Investment	4,853	4,921
Financial [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	309	329
Alternative Investment	$ 521	$ 611
Financial [Member] | Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Financial [Member] | Maximum [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
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	$ 749	$ 422
Alternative Investment	$ 674	$ 712
Real Estate Funds [Member] | Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Real Estate Funds [Member] | Maximum [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
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	$ 158	$ 80
Alternative Investment	$ 220	$ 263
Distressed Alternative Investments [Member] | Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Distressed Alternative Investments [Member] | Maximum [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
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	$ 272	$ 272
Alternative Investment	$ 81	$ 104
Private Credit Alternative Investments [Member] | Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	3 years	3 years
Private Credit Alternative Investments [Member] | Maximum [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
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	$ 1,852	$ 2,160
Alternative Investment	$ 3,039	$ 2,844
Private Equity Funds [Member] | Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Private Equity Funds [Member] | Maximum [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
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	$ 90	$ 116
Vintage Alternative Investments [Member] | Minimum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	1 year	1 year
Vintage Alternative Investments [Member] | Maximum [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	2 years	2 years
Investment Funds 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	$ 228	$ 271

Investments (Schedule Of Compon

Investments (Schedule Of Components Of Restricted Assets) (Detail) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Trust funds	$ 12,522	$ 14,004
Deposits with U.S. regulatory authorities	2,424	2,466
Deposits With Non United States Regulatory Authorities	2,807	2,709
Assets pledged under repurchase agreements	1,460	1,464
Other pledged assets	523	490
Total restricted assets	$ 19,736	$ 21,133

Fair Value Measurements (Financ

Fair Value Measurements (Financial Instruments Measured At Fair Value On Recurring Basis) (Detail) - USD ($) $ in Millions		Jun. 30, 2020		Mar. 31, 2020	Dec. 31, 2019		Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		$ 86,712			$ 85,488
Equity securities, at fair value		2,394			812
Short-term investments		4,003			4,291
Other Investments		5,923			6,062
Securities lending collateral		1,832			994
U.S. Treasury / Agency
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		2,875			3,283
Non-U.S.
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		24,607			23,707
Corporate and asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		33,917			31,791
Mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		18,198			19,192
Municipal
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		7,115			7,515
Investment Funds Limited Partnerships Partially Owned Investment Companies Fair Value [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Other Investments		4,853			4,921
Other Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Other Investments		90			95
Policy Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Other Investments		226
Fair Value, Recurring [Member] | Level 1
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		2,316			2,664
Equity securities, at fair value		2,329			728
Short-term investments		2,707			2,803
Other Investments		361	[1]		412	[2]
Securities lending collateral		0			0
Investment derivative instruments, assets		19			24
Other Derivative Instruments Fair Value		1			2
Separate Account Asset		3,394			3,437
Total assets measured at fair value		11,127	[1]		10,070	[2]
Investment derivative instruments, liabilities		96			93
Other derivative instruments, liability					13
Liabilities Related to Investment Contracts, Fair Value Disclosure		96			106
Fair Value, Recurring [Member] | Level 1 | U.S. Treasury / Agency
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		2,316			2,664
Fair Value, Recurring [Member] | Level 1 | Non-U.S.
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		0			0
Fair Value, Recurring [Member] | Level 1 | Corporate and asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		0			0
Fair Value, Recurring [Member] | Level 1 | Mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		0			0
Fair Value, Recurring [Member] | Level 1 | Municipal
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		0			0
Fair Value, Recurring [Member] | Level 2
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		82,498			80,864
Equity securities, at fair value		1			15
Short-term investments		1,294			1,482
Other Investments		383	[1]		377	[2]
Securities lending collateral		1,832			994
Investment derivative instruments, assets		0			0
Other Derivative Instruments Fair Value		0			0
Separate Account Asset		132			136
Total assets measured at fair value		86,140	[1]		83,868	[2]
Investment derivative instruments, liabilities		0			0
Other derivative instruments, liability					0
Liabilities Related to Investment Contracts, Fair Value Disclosure		0			0
Fair Value, Recurring [Member] | Level 2 | U.S. Treasury / Agency
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		559			619
Fair Value, Recurring [Member] | Level 2 | Non-U.S.
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		24,138			23,258
Fair Value, Recurring [Member] | Level 2 | Corporate and asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		32,548			30,340
Fair Value, Recurring [Member] | Level 2 | Mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		18,138			19,132
Fair Value, Recurring [Member] | Level 2 | Municipal
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		7,115			7,515
Fair Value, Recurring [Member] | Level 3
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		1,898			1,960
Equity securities, at fair value		64			69
Short-term investments		2			6
Other Investments		10	[1]		10	[2]
Securities lending collateral		0			0
Investment derivative instruments, assets		0			0
Other Derivative Instruments Fair Value		0			0
Separate Account Asset		0			0
Total assets measured at fair value		1,974	[1]		2,045	[2]
Investment derivative instruments, liabilities		0			0
Other derivative instruments, liability					0
Liabilities Related to Investment Contracts, Fair Value Disclosure		928			456
Fair Value, Recurring [Member] | Level 3 | U.S. Treasury / Agency
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		0			0
Fair Value, Recurring [Member] | Level 3 | Non-U.S.
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		469			449
Fair Value, Recurring [Member] | Level 3 | Corporate and asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		1,369			1,451
Fair Value, Recurring [Member] | Level 3 | Mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		60			60
Fair Value, Recurring [Member] | Level 3 | Municipal
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		0			0
Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		86,712			85,488
Equity securities, at fair value		2,394			812
Short-term investments		4,003			4,291
Other Investments		754	[1]		799	[2]
Securities lending collateral		1,832			994
Investment derivative instruments, assets		19			24
Other Derivative Instruments Fair Value		1			2
Separate Account Asset		3,526			3,573
Total assets measured at fair value		99,241	[1]		95,983	[2]
Investment derivative instruments, liabilities		96			93
Other derivative instruments, liability					13
Liabilities Related to Investment Contracts, Fair Value Disclosure		1,024			562
Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | U.S. Treasury / Agency
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		2,875			3,283
Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Non-U.S.
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		24,607			23,707
Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Corporate and asset-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		33,917			31,791
Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		18,198			19,192
Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member] | Municipal
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Available for sale, Fair Value		7,115			7,515
Guaranteed Minimum Income Benefit [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value		928		$ 1,141	456		$ 403	$ 338	$ 452
Guaranteed Minimum Income Benefit [Member] | Fair Value, Recurring [Member] | Level 1
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value		0	[3]		0	[4]
Guaranteed Minimum Income Benefit [Member] | Fair Value, Recurring [Member] | Level 2
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value		0	[3]		0	[4]
Guaranteed Minimum Income Benefit [Member] | Fair Value, Recurring [Member] | Level 3
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value	[5]	928			456	[4]
Guaranteed Minimum Income Benefit [Member] | Fair Value, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value		$ 928	[3]		$ 456	[4]
[1]	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,853 million, policy loans of $226 million and other investments of $90 million at June 30, 2020 measured using NAV as a practical expedient.
[2]	Excluded from the table above are partially-owned investments, investment funds, and limited partnerships of $4,921 million and other investments of $95 million at December 31, 2019 measured using NAV as a practical expedient.
[3]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.
[4]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.
[5]	The weighted average lapse and annuitization rates are determined by weighting each treaty's rates by the GLB contracts fair value.

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule Of Significant Unobservable Inputs Used In Level 3 Liability Valuations) (Detail) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019		Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurements, Valuation Processes, Description		Actuarial model
GLB
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value		$ 928	$ 1,141	$ 456		$ 403	$ 338	$ 452
Guaranteed Benefit Liability, Net		$ 1,372	$ 1,591	897		$ 815	$ 741	$ 861
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]	4.10%
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		52.00%
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]	$ 928		$ 456	[2]
[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. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.

Fair Value Measurements (Assets

Fair Value Measurements (Assets Measured At Fair Value Using Significant Unobservable Inputs) (Detail) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2020		Jun. 30, 2019		Jun. 30, 2020		Jun. 30, 2019		Mar. 31, 2020		Dec. 31, 2019		Mar. 31, 2019		Dec. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers Into Level 3, Asset						$ 0		$ 0
Level 3 | Non-U.S.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of Period, Assets		$ 465		$ 360		449		345
Transfers Into Level 3, Asset				0		0		3
Transfers out of Level 3, Assets		(13)				(16)		(15)
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)		(6)		0		(20)		6
Net Realized Gains/ (Losses), Assets		(1)		0		(3)		(1)
Purchases, Assets		67		43		149		96
Sales, Assets		(16)		(14)		(62)		(19)
Settlements, Assets		(27)		(18)		(28)		(44)
Balance-End of Period, Assets		469		371		469		371
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0		0		0		0
Level 3 | Corporate and asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of Period, Assets		1,502		1,342		1,451		1,299
Transfers Into Level 3, Asset				10		91		15
Transfers out of Level 3, Assets		(71)				(72)		0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)		1		1		(44)		5
Net Realized Gains/ (Losses), Assets		(13)		(1)		(26)		0
Purchases, Assets		83		121		222		249
Sales, Assets		(48)		(36)		(67)		(73)
Settlements, Assets		(85)		(78)		(186)		(136)
Balance-End of Period, Assets		1,369		1,359		1,369		1,359
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		5		(1)		(9)		(1)
Level 3 | Mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance- Beginning of Period, Assets		60		78		60		61
Transfers Into Level 3, Asset				0
Transfers out of Level 3, Assets		0				0		0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0		0		0
Net Realized Gains/ (Losses), Assets		0		0		0		0
Purchases, Assets		0		0		0		18
Sales, Assets		0		(1)		0		(1)
Settlements, Assets		0		(1)		0		(2)
Balance-End of Period, Assets		60		76		60		76
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0		0		0		0
Level 3 | Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		0				0
Balance- Beginning of Period, Assets		67		55		69		57
Transfers Into Level 3, Asset				0
Transfers out of Level 3, Assets		0				0		0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)		(1)		1		0		2
Net Realized Gains/ (Losses), Assets		(1)		(1)		(3)		(3)
Purchases, Assets		8		5		11		14
Sales, Assets		(9)		(4)		(13)		(14)
Settlements, Assets		0		0		0		0
Balance-End of Period, Assets		64		56		64		56
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		1		(1)		(1)		(2)
Level 3 | Short-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		0				0
Balance- Beginning of Period, Assets		1		0		6		1
Transfers Into Level 3, Asset				0
Transfers out of Level 3, Assets		0				0		0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0		0		0
Net Realized Gains/ (Losses), Assets		0		0		0		0
Purchases, Assets		1		4		2		4
Sales, Assets		0		0		0		0
Settlements, Assets		0		0		(6)		(1)
Balance-End of Period, Assets		2		4		2		4
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0		0		0		0
Level 3 | Other Long-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		0				0
Balance- Beginning of Period, Assets		10		11		10		11
Transfers Into Level 3, Asset				0
Transfers out of Level 3, Assets		0				0		0
Asset, Net realized Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0		0		0
Net Realized Gains/ (Losses), Assets		0		0		0		0
Purchases, Assets		0		0		0		0
Sales, Assets		0		0		0		0
Settlements, Assets		0		0		0		0
Balance-End of Period, Assets		10		11		10		11
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0		0		0		0
Available-for-sale Securities [Member] | Level 3 | Non-U.S.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		(5)				(20)
Available-for-sale Securities [Member] | Level 3 | Corporate and asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		7				(37)
Available-for-sale Securities [Member] | Level 3 | Mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		0				0
Guaranteed Minimum Income Benefit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value		928		403		928		403		$ 1,141		$ 456		$ 338		$ 452
Guaranteed Minimum Income Benefit [Member] | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		0				0
Guaranteed Minimum Income Benefit [Member] | Fair Value, Recurring [Member] | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value	[1]	928				928						456	[2]
Guaranteed Minimum Income Benefit [Member] | Guarantees [Member] | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value		928	[3],[4]	403	[4]	928	[3],[4]	403	[4]	$ 1,141	[3]	$ 456		$ 338	[4]	$ 452	[4]
Transfers into level 3, liability				0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		(213)	[3]	65	[4]	472		(49)	[4]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements		0		0		0		0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)		(213)	[3]	$ 65	[4]	472		(49)	[4]
Transfers out of Level 3, Liabilities		$ 0				$ 0		$ 0
[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. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.
[3]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $1,372 million at June 30, 2020, and $1,591 million at March 31, 2020, which includes a fair value derivative adjustment of $928 million and $1,141 million, respectivel
[4]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $815 million at June 30, 2019, and $741 million at March 31, 2019, which includes a fair value derivative adjustment of $403 million and $338 million, respectively

Fair value measurements Fair _2

Fair value measurements Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation (Details) - Guaranteed Minimum Income Benefit [Member] - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2020		Jun. 30, 2019		Jun. 30, 2020		Jun. 30, 2019		Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Guaranteed Benefit Liability, Net		$ 1,372		$ 815		$ 1,372		$ 815		$ 1,591	$ 897	$ 741	$ 861
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - Beginning of Period, Liabilities		1,141		338		456		452
Balance - End of Period, Liabilities		928		403		928		403
Guarantees [Member] | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance - Beginning of Period, Liabilities		1,141	[1]	338	[2]	456		452	[2]
Transfers into level 3, liability				0		0		0
Transfers out of Level 3, Liabilities		0				0		0
Change in Net Unrealized Gains (Losses) included in OCI, Liabilities		0		0		0		0
Net Realized Gains/Losses, Liabilities		(213)	[1]	65	[2]	472		(49)	[2]
Purchases, Liabilities		0		0		0		0
Sales, Liabilities		0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements		0		0		0		0
Balance - End of Period, Liabilities	[2]	928	[1]	403		928	[1]	403
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)		$ (213)	[1]	$ 65	[2]	$ 472		$ (49)	[2]
[1]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $1,372 million at June 30, 2020, and $1,591 million at March 31, 2020, which includes a fair value derivative adjustment of $928 million and $1,141 million, respectivel
[2]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets. The liability for GLB reinsurance was $815 million at June 30, 2019, and $741 million at March 31, 2019, which includes a fair value derivative adjustment of $403 million and $338 million, respectively

Fair Value Measurements (Carryi

Fair Value Measurements (Carrying Values And Fair Values Of Financial Instruments Not Measured At Fair Value) (Detail) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	$ 12,620	$ 13,005
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)	11,896	12,581
Debt securities, held to maturity, net carrying value	11,845
Repurchase agreements	1,409	1,416
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term debt	1,300	1,299
Long-term debt	13,656	13,559
Total liabilities	126,714	121,612
U.S. Treasury / Agency
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	1,315	1,347
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)	1,242	1,318
Debt securities, held to maturity, net carrying value	1,242
Non-U.S.
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	1,370	1,485
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)	1,278	1,423
Debt securities, held to maturity, net carrying value	1,270
Corporate and asset-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	2,428	2,468
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)	2,232	2,349
Debt securities, held to maturity, net carrying value	2,191
Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	2,331	2,396
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)	2,189	2,331
Debt securities, held to maturity, net carrying value	2,188
Municipal
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	5,176	5,309
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)	4,955	5,160
Debt securities, held to maturity, net carrying value	4,954
Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	1,257	1,292
Repurchase agreements	0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term Debt, Fair Value	0	0
Long-term Debt, Fair Value	0	0
Trust preferred securities	0	0
Total liabilities	0	0
Level 1 | U.S. Treasury / Agency
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	1,257	1,292
Level 1 | Non-U.S.
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	0
Level 1 | Corporate and asset-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	0
Level 1 | Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	0
Level 1 | Municipal
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	0
Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	11,363	11,681
Repurchase agreements	1,409	1,416
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term Debt, Fair Value	1,309	1,307
Long-term Debt, Fair Value	15,650	15,048
Trust preferred securities	453	467
Total liabilities	18,821	18,238
Level 2 | U.S. Treasury / Agency
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	58	55
Level 2 | Non-U.S.
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	1,370	1,485
Level 2 | Corporate and asset-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	2,428	2,436
Level 2 | Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	2,331	2,396
Level 2 | Municipal
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	5,176	5,309
Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	32
Repurchase agreements	0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term Debt, Fair Value	0	0
Long-term Debt, Fair Value	0	0
Trust preferred securities	0	0
Total liabilities	0	0
Level 3 | U.S. Treasury / Agency
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	0
Level 3 | Non-U.S.
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	0
Level 3 | Corporate and asset-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	32
Level 3 | Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	0
Level 3 | Municipal
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	0	0
Estimate of Fair Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	12,620	13,005
Repurchase agreements	1,409	1,416
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term Debt, Fair Value	1,309	1,307
Long-term Debt, Fair Value	15,650	15,048
Trust preferred securities	453	467
Total liabilities	18,821	18,238
Estimate of Fair Value Measurement [Member] | U.S. Treasury / Agency
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	1,315	1,347
Estimate of Fair Value Measurement [Member] | Non-U.S.
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	1,370	1,485
Estimate of Fair Value Measurement [Member] | Corporate and asset-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	2,428	2,468
Estimate of Fair Value Measurement [Member] | Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	2,331	2,396
Estimate of Fair Value Measurement [Member] | Municipal
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Held-to-maturity, Fair Value	5,176	5,309
Reported Value Measurement [Member]
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)		12,581
Debt securities, held to maturity, net carrying value	11,845
Repurchase agreements	1,409	1,416
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Short-term debt	1,300	1,299
Long-term debt	13,656	13,559
Trust preferred securities	308	308
Total liabilities	16,673	16,582
Reported Value Measurement [Member] | U.S. Treasury / Agency
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)		1,318
Debt securities, held to maturity, net carrying value	1,242
Reported Value Measurement [Member] | Non-U.S.
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)		1,423
Debt securities, held to maturity, net carrying value	1,270
Reported Value Measurement [Member] | Corporate and asset-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)		2,349
Debt securities, held to maturity, net carrying value	2,191
Reported Value Measurement [Member] | Mortgage-backed securities
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)		2,331
Debt securities, held to maturity, net carrying value	2,188
Reported Value Measurement [Member] | Municipal
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Fixed maturities held to maturity, at amortized cost, net of valuation allowance - $51 at June 30, 2020 (fair value – $12,620 and $13,005)		$ 5,160
Debt securities, held to maturity, net carrying value	$ 4,954

Reinsurance (Reinsurance Recove

Reinsurance (Reinsurance Recoverable on Ceded Reinsurance) (Details) - USD ($) $ in Millions		Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Ceded Credit Risk [Line Items]
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	[1]	$ 14,361	$ 14,181	$ 14,233	$ 14,689
Reinsurance Recoverable for Paid Claims and Claims Adjustments		846	1,000
Reinsurance recoverable on losses and loss expenses, net of valuation allowance - $303 and $316		15,207	15,181
Reinsurance recoverable on policy benefits		197	197
Reinsurance Recoverables on Unpaid Losses, Allowance		240	240
Reinsurance Recoverables on Paid Losses, Allowance		63	76
Reinsurance Recoverable, Allowance for Credit Loss		303	316
Reinsurance Recoverables on Future Policy Benefits, Allowance		$ 4	$ 4
[1]	Net of valuation allowance for uncollectible reinsurance.

Reinsurance (Details)

Reinsurance (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020USD ($)
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Reinsurance Recoverable, Allowance for Credit Loss, Beginning of period	$ 316
Reinsurance Recoverable, Credit Loss Expense (Reversal)	5
Reinsurance, Loss on Uncollectible Accounts in Period, Amount	(19)
Reinsurance Recoverable, Allowance for Credit Loss, Other	1
Reinsurance Recoverable, Allowance for Credit Loss, end of period	$ 303

Unpaid losses and loss expens_3

Unpaid losses and loss expenses (RF) (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019
Unpaid Losses and Loss Expenses [Roll Forward]
Gross unpaid losses and loss expenses – beginning of period		$ 62,690	$ 62,960
Reinsurance recoverable on unpaid losses - beginning of period (1)	[1]	(14,181)	(14,689)
Net unpaid losses and loss expenses – beginning of period		48,509	48,271
Current Year Claims and Claims Adjustment Expense		11,111	9,224
Prior Year Claims and Claims Adjustment Expense	[2]	(49)	(411)
Total, Incurred		11,062	8,813
Net loss and loss expenses paid, Current Year		2,263	2,288
Net loss and loss expenses paid, Prior Years		5,842	5,823
Total, Paid		8,105	8,111
Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Revaluation And Other		(128)	(1)
Net unpaid losses and loss expenses – end of period		51,338	48,972
Reinsurance recoverable on unpaid losses (1)	[1]	14,361	14,233
Gross unpaid losses and loss expenses – end of period		65,699	63,205
prior period development, net adjustments		6	$ 19
Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease), Gross		3,009
Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease)		$ 2,829
[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 $6 million and $19 million for the six months ended June 30, 2020 and 2019, respectively.

Unpaid losses and loss expens_4

Unpaid losses and loss expenses Unpaid losses and loss expenses (PPD table) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	$ 75	$ (188)	$ (43)	$ (392)
North America Commercial P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(146)	(185)	(251)	(316)
North America Personal P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(1)	(16)	0	(26)
North American Agriculture Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0	(14)	(61)
Overseas General Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(36)	(20)	(40)	(24)
Global Reinsurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(16)	0	(23)	(8)
Corporate Segment [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	274	33	285	43
Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(38)	18	(124)	(130)
Short Tail [Member] | North America Commercial P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(5)	21	(67)	(45)
Short Tail [Member] | North America Personal P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(1)	(16)	0	(26)
Short Tail [Member] | North American Agriculture Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0	(14)	(61)
Short Tail [Member] | Overseas General Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(35)	(20)	(39)	(24)
Short Tail [Member] | Global Reinsurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	3	33	(4)	26
Short Tail [Member] | Corporate Segment [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0	0	0
Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	113	(206)	81	(262)
Long Tail [Member] | North America Commercial P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(141)	(206)	(184)	(271)
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	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	0	0
Long Tail [Member] | Overseas General Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(1)	0	(1)	0
Long Tail [Member] | Global Reinsurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(19)	(33)	(19)	(34)
Long Tail [Member] | Corporate Segment [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	$ 274	$ 33	$ 285	$ 43

Unpaid losses and loss expens_5

Unpaid losses and loss expenses Unpaid losses and loss expenses (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	$ 75	$ (188)	$ (43)	$ (392)
Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	113	(206)	81	(262)
Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(38)	18	(124)	(130)
North America Commercial P&C Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(146)	(185)	(251)	(316)
North America Commercial P&C Insurance [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(141)	(206)	(184)	(271)
North America Commercial P&C Insurance [Member] | Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(5)	21	(67)	(45)
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				(54)
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			(36)
North America Commercial P&C Insurance [Member] | Workers' Compensation Insurance [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(152)	(163)	(182)
North America Commercial P&C Insurance [Member] | Other [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	5		5
North America Commercial P&C Insurance [Member] | Accident Year 2013 and prior [Member] | Commercial Excess and Umbrella [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development				(31)
North America Commercial P&C Insurance [Member] | Accident year 2015 and prior [Member] | General Liability [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		(50)
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] | General Liability [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(59)
North America Commercial P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2017 [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] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Surety Product Line [Member] | Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development			(31)
North America Commercial P&C Insurance [Member] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Workers' Compensation Insurance [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		(61)		(200)
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			(37)
North America Commercial P&C Insurance [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Workers' Compensation Insurance [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(62)
North America Commercial P&C Insurance [Member] | Accident years 2015 to 2019 [Member] | Commercial Excess and Umbrella [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development			40
North America Commercial P&C Insurance [Member] | Accident years 2015 to 2019 [Member] | Other [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development			75
North America Commercial P&C Insurance [Member] | Accident years 2014 - 2018 [Member] | Other [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development		25		31
North America Agricultural Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0	(14)	(61)
North America Agricultural Insurance [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0	0	0
North America Agricultural Insurance [Member] | Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0	(14)	(61)
Corporate Segment [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	274	33	285	43
Corporate Segment [Member] | Discontinued Operations [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	20		31
Corporate Segment [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	274	33	285	43
Corporate Segment [Member] | Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	0	0	0	0
Corporate Segment [Member] | Other [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development			254
Overseas General Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(36)	(20)	(40)	(24)
Overseas General Insurance [Member] | Long Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(1)	0	(1)	0
Overseas General Insurance [Member] | Short Tail [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	(35)	$ (20)	(39)	$ (24)
Overseas General Insurance [Member] | Marine [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Net Prior Period Development	$ (19)		$ (22)

Commitments, Contingencies, A_3

Commitments, Contingencies, And Guarantees (Narrative) (Detail) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Financial Instruments Owned and Pledged as Collateral [Line Items]
Derivative liability subject to a master netting agreement	$ 71	$ 75
Repurchase agreements	1,409	1,416
Purchase Commitment, Remaining Minimum Amount Committed	747
Carrying value of limited partnerships and partially-owned investment companies included in other investments	4,600
Funding commitments relating to limited partnerships and partially-owned investment companies	3,300
Unrecognized tax benefits	48
Operating Lease, Right-of-Use Asset	483	551
Operating Lease, Liability	$ 531	$ 603

Commitments, Contingencies, A_4

Commitments, Contingencies, And Guarantees (Balance Sheet Locations, Fair Values In Asset Or (Liability) Position, And Notional Values/Payment Provisions Of Derivative Instruments) (Detail) - USD ($) $ in Millions		Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019		Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Future policy benefits		$ 5,895		$ 5,814
Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		2,462		2,579
Options/Futures contracts on notes, bonds, and equities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		1,398		1,615
Convertible securities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[1]	10		5
Total investment and embedded derivative instruments
Derivatives, Fair Value [Line Items]
Fair Value, Asset		27		28
Derivative, Notional Amount		3,870		4,199
Futures contracts on equities
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	[2]	598		613
Other
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		97		63
Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount		695		676
Guaranteed Minimum Income Benefit [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset	[3]	0		0
Derivative, Notional Amount	[3]	2,196		1,510
Future policy benefits		444		441
Other Assets [Member] | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Fair Value, Asset		16		11
Other Assets [Member] | Options/Futures contracts on notes, bonds, and equities
Derivatives, Fair Value [Line Items]
Fair Value, Asset		3		13
Other Assets [Member] | Futures contracts on equities
Derivatives, Fair Value [Line Items]
Fair Value, Asset	[2]	0		0
Other Assets [Member] | Other
Derivatives, Fair Value [Line Items]
Fair Value, Asset		1		2
Other Assets [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		1		2
Fixed Maturities [Member] | Convertible securities
Derivatives, Fair Value [Line Items]
Fair Value, Asset	[1]	8		4
Equity Securities [Member] | Convertible securities
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[1]	0		0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(85)		(78)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Options/Futures contracts on notes, bonds, and equities
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(11)		(15)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Total investment and embedded derivative instruments
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(96)		(93)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Futures contracts on equities
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[2]	0		(13)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other
Derivatives, Fair Value [Line Items]
Fair Value, Liability		0		0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		0		(13)
Balance Sheet Location Accounts Payable Future Policy Benefits [Member] | Guaranteed Minimum Income Benefit [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[3]	(1,372)		(897)
Guaranteed Minimum Income Benefit [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value		928	$ 1,141	456		$ 403	$ 338	$ 452
Guaranteed Benefit Liability, Net		1,372	$ 1,591	897		$ 815	$ 741	$ 861
Guaranteed Minimum Income Benefit [Member] | Fair Value, Recurring [Member] | Level 3
Derivatives, Fair Value [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value	[4]	$ 928		$ 456	[5]
[1]	Includes fair value of embedded derivatives.
[2]	Related to GMDB and GLB book of business.
[3]	Includes both future policy benefits reserves of $444 million and $441 million and fair value derivative adjustment of $928 million and $456 million at June 30, 2020 and December 31, 2019, respectively. 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.
[4]	The weighted average lapse and annuitization rates are determined by weighting each treaty's rates by the GLB contracts fair value.
[5]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the Consolidated balance sheets.

Commitments, Contingencies, A_5

Commitments, Contingencies, And Guarantees (Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative		$ 123	$ (259)	$ (424)	$ (339)
Foreign currency forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative		10	(22)	53	(37)
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative		0	(135)	0	(215)
All Other Futures Contracts, Options and equities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative		3	(25)	(24)	(61)
Convertible securities
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative	[1]	1	1	0	2
Total investment and embedded derivative instruments
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative		14	(181)	29	(311)
GLB
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative	[2]	213	(65)	(472)	49
Futures contracts on equities
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative	[3]	(103)	(20)	22	(83)
Other
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative		(1)	7	(3)	6
Guaranteed Living Benefit And Other Derivative Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Derivative		$ 109	$ (78)	$ (453)	$ (28)
[1]	Includes embedded derivatives.
[2]	Excludes foreign exchange gains (losses) related to GLB.
[3]	Related to GMDB and GLB book of business.

Commitments, contingencies, a_6

Commitments, contingencies, and guarantees Commitments, Contingencies, And Guarantees (Transactions accounted for as secured borrowings) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	$ 1,832	$ 994
Securities lending payable	1,832	994
Cash [Member] | Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	665	346
U.S. Treasury / Agency | Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	52	6
Foreign [Member] | Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	1,059	595
Corporate and asset-backed securities | Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	20	5
Mortgage-backed securities | Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	0	18
Equity Securities [Member] | Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Securities lending collateral	$ 36	$ 24

Commitments, contingencies, a_7

Commitments, contingencies, and guarantees Commitments, Contingencies, And Guarantees (Collateral pledged under repurchase agreements) (Details) - USD ($) $ in Millions		Jun. 30, 2020	Dec. 31, 2019
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements		$ 1,460	$ 1,464
Repurchase agreements		1,409	1,416
Cash [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements		1	2
U.S. Treasury / Agency
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements		109	107
Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements		1,350	1,355
Repurchase Agreements [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Secured Borrowings, Gross, Difference, Amount	[1]	51	48
Maturity Less than 30 Days [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements			508
Maturity Less than 30 Days [Member] | Cash [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements			2
Maturity Less than 30 Days [Member] | U.S. Treasury / Agency
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements			107
Maturity Less than 30 Days [Member] | Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements			399
Maturity 30 to 90 Days [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements			476
Maturity 30 to 90 Days [Member] | Cash [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements			0
Maturity 30 to 90 Days [Member] | U.S. Treasury / Agency
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements			0
Maturity 30 to 90 Days [Member] | Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements			476
Maturity Greater than 90 Days [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements		1,460	480
Maturity Greater than 90 Days [Member] | Cash [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements		1	0
Maturity Greater than 90 Days [Member] | U.S. Treasury / Agency
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements		109	0
Maturity Greater than 90 Days [Member] | Mortgage-backed securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Assets pledged under repurchase agreements		$ 1,350	$ 480
[1]	Per the repurchase agreements, the amount of collateral posted is required to exceed the amount of gross liability.

Shareholders' equity (Details)

Shareholders' equity (Details) - SFr / shares	Jun. 30, 2020	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Common Shares, par value	SFr 24.15	SFr 24.15
Common Shares in treasury, shares	28,423,841	27,812,297

Shareholders' equity Dividends

Shareholders' equity Dividends Declared (Details)	3 Months Ended				6 Months Ended
	Jun. 30, 2020$ / shares	Jun. 30, 2020SFr / shares	Jun. 30, 2019$ / shares	Jun. 30, 2019SFr / shares	Jun. 30, 2020$ / shares	Jun. 30, 2020SFr / shares	Jun. 30, 2019$ / shares	Jun. 30, 2019SFr / shares	May 20, 2020$ / shares	May 31, 2019$ / shares	May 31, 2018$ / shares
Equity, Class of Treasury Stock [Line Items]
Annual dividend per share approved by shareholders									$ 3.12	$ 3	$ 2.92
Common Stock, Dividend Rate Approved									$ 0.78	$ 0.75	$ 0.73
United States of America, Dollars
Equity, Class of Treasury Stock [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.78		$ 0.75		$ 1.53		$ 1.48
Switzerland, Francs
Equity, Class of Treasury Stock [Line Items]
Common Stock, Dividends, Per Share, Declared | SFr / shares		SFr 0.75		SFr 0.75		SFr 1.47		SFr 1.47

Shareholders' equity Share Repu

Shareholders' equity Share Repurchases (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Nov. 21, 2019	Dec. 01, 2018
Dec 2018 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount						$ 1,500
Number of shares repurchased		2,584,466		5,338,220
Cost of shares repurchased		$ 376		$ 743
Repurchase authorization remaining at end of period		$ 736		$ 736
Nov 2019 Stock Repurchase Plan [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 1,500
Number of shares repurchased	0		2,266,150
Cost of shares repurchased	$ 0		$ 326
Repurchase authorization remaining at end of period	$ 1,124		$ 1,124

Share-Based Compensation (Detai

Share-Based Compensation (Detail) - $ / shares	Feb. 27, 2020	Jun. 30, 2020
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	1,957,505
Weighted-average grant date fair value for stock options granted	$ 19.89
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	1,002,341
Grant date fair value of awards except for options granted to employees and officers of the company	$ 150.11
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	203,533
Grant date fair value of awards except for options granted to employees and officers of the company	$ 150.11
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	344,501
Grant date fair value of awards except for options granted to employees and officers of the company	$ 150.11

Postretirement benefits Compone

Postretirement benefits Components of net periodic benefit costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	$ 1	$ 15	$ 2	$ 30
Non-service (benefit) cost	(35)	(22)	(69)	(43)
Net periodic (benefit) cost	(34)	(7)	(67)	(13)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0	0	0
Interest cost	0	1	1	2
Expected return on plan assets	(1)	(1)	(2)	(2)
Defined Benefit Plan, Amortization of Gain (Loss)	0	0	0	0
Amortization of prior service cost	(20)	(20)	(40)	(40)
Settlements	0	0	0	0
Non-service (benefit) cost	(21)	(20)	(41)	(40)
Net periodic (benefit) cost	(21)	(20)	(41)	(40)
Losses and loss expenses | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	1	0	3
Non-service (benefit) cost	(3)	(2)	(6)	(4)
Losses and loss expenses | Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0	0	0
Non-service (benefit) cost	(2)	(2)	(4)	(4)
Administrative Expense | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	1	14	2	27
Non-service (benefit) cost	(32)	(20)	(63)	(39)
Administrative Expense | Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0	0	0
Non-service (benefit) cost	(19)	(18)	(37)	(36)
Foreign Plan [Member] | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	1	2	2	5
Interest cost	5	7	11	14
Expected return on plan assets	(11)	(11)	(21)	(22)
Defined Benefit Plan, Amortization of Gain (Loss)	1	1	1	1
Amortization of prior service cost	0	0	0	0
Settlements	0	0	0	0
Non-service (benefit) cost	(5)	(3)	(9)	(7)
Net periodic (benefit) cost	(4)	(1)	(7)	(2)
UNITED STATES | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	13	0	25
Interest cost	25	29	50	59
Expected return on plan assets	(56)	(48)	(112)	(95)
Defined Benefit Plan, Amortization of Gain (Loss)	0	0	0	0
Amortization of prior service cost	0	0	0	0
Settlements	1	0	2	0
Non-service (benefit) cost	(30)	(19)	(60)	(36)
Net periodic (benefit) cost	$ (30)	$ (6)	$ (60)	$ (11)

Segment information Segment Inf

Segment information Segment Information (narrative Detail (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Gain (Loss) on Derivative	$ (123)	$ 259	$ 424	$ 339
Net investment income	827	859	1,688	1,695
North America Agricultural Insurance [Member]
Segment Reporting Information [Line Items]
Segment Income Loss Including Gains Losses On Crop Derivatives	31
Gain (Loss) on Derivative	(1)
Net investment income	7	4	16	14
Segment Life [Member]
Segment Reporting Information [Line Items]
Net investment income	95	$ 97	$ 190	$ 186
Management Underwriting Income (Loss)	71
Gains(Losses) On Fair Value Changes In Separate Account Assets	$ 40

Segment Information (Operations

Segment Information (Operations By Segment) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net premiums written	$ 8,355	$ 8,343	$ 16,332	$ 15,656
Net premiums earned	8,128	7,891	15,922	15,028
Losses and loss expenses	6,577	4,715	11,062	8,813
Policy benefits	223	161	352	357
Policy acquisition costs	1,593	1,544	3,208	3,008
Administrative expenses	727	758	1,468	1,468
Underwriting income (loss)	(992)	713	(168)	1,382
Net investment income (loss)	827	859	1,688	1,695
Other (income) expense	58	(230)	113	(269)
Amortization of purchased intangibles	72	77	145	153
Segment Income (loss)	(295)	1,725	1,262	3,193
Net Realized Gains Losses	30	(223)	(928)	(320)
Interest expense	128	140	260	280
Chubb integration expenses	0	4	0	7
Income tax benefit	(62)	208	153	396
Net income (loss)	(331)	1,150	(79)	2,190
North America Commercial P&C Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	3,720	3,534	6,972	6,485
Net premiums earned	3,595	3,390	6,971	6,475
Losses and loss expenses	3,498	2,214	5,679	4,187
Policy benefits	0	0	0	0
Policy acquisition costs	471	459	963	918
Administrative expenses	249	259	508	499
Underwriting income (loss)	(623)	458	(179)	871
Net investment income (loss)	507	521	1,023	1,031
Other (income) expense	4	2	1	(3)
Amortization of purchased intangibles	0	0	0	0
Segment Income (loss)	(120)	977	843	1,905
North America Personal P&C Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	1,327	1,309	2,434	2,365
Net premiums earned	1,192	1,168	2,392	2,322
Losses and loss expenses	762	747	1,445	1,504
Policy benefits	0	0	0	0
Policy acquisition costs	231	237	476	468
Administrative expenses	66	71	134	139
Underwriting income (loss)	133	113	337	211
Net investment income (loss)	65	64	131	128
Other (income) expense	1	1	3	1
Amortization of purchased intangibles	3	3	6	6
Segment Income (loss)	194	173	459	332
North America Agricultural Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	461	466	618	596
Net premiums earned	376	378	470	433
Losses and loss expenses	312	316	375	289
Policy benefits	0	0	0	0
Policy acquisition costs	29	27	40	34
Administrative expenses	3	4	7	5
Underwriting income (loss)	32	31	48	105
Net investment income (loss)	7	4	16	14
Other (income) expense	1	1	1	1
Amortization of purchased intangibles	6	7	13	14
Segment Income (loss)	32	27	50	104
Overseas General Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	2,021	2,258	4,619	4,653
Net premiums earned	2,194	2,225	4,501	4,339
Losses and loss expenses	1,485	1,125	2,743	2,231
Policy benefits	0	0	0	0
Policy acquisition costs	624	629	1,266	1,225
Administrative expenses	241	265	499	514
Underwriting income (loss)	(156)	206	(7)	369
Net investment income (loss)	124	151	269	295
Other (income) expense	8	3	12	7
Amortization of purchased intangibles	11	12	23	23
Segment Income (loss)	(51)	342	227	634
Global Reinsurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	207	197	425	399
Net premiums earned	163	159	349	327
Losses and loss expenses	73	90	160	166
Policy benefits	0	0	0	0
Policy acquisition costs	42	42	87	85
Administrative expenses	9	7	19	17
Underwriting income (loss)	39	20	83	59
Net investment income (loss)	51	55	105	111
Other (income) expense	(8)	(15)	(23)	(24)
Amortization of purchased intangibles	0	0	0	0
Segment Income (loss)	98	90	211	194
Life Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums written	619	579	1,264	1,158
Net premiums earned	608	571	1,239	1,132
Losses and loss expenses	171	189	373	391
Policy benefits	223	161	352	357
Policy acquisition costs	196	150	376	278
Administrative expenses	82	78	158	157
Underwriting income (loss)	(64)	(7)	(20)	(51)
Net investment income (loss)	95	97	190	186
Other (income) expense	(57)	(7)	(13)	(47)
Amortization of purchased intangibles	1	1	2	1
Segment Income (loss)	87	96	181	181
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Net premiums written	0	0	0	0
Net premiums earned	0	0	0	0
Losses and loss expenses	276	34	287	45
Policy benefits	0	0	0	0
Policy acquisition costs	0	0	0	0
Administrative expenses	77	74	143	137
Underwriting income (loss)	(353)	(108)	(430)	(182)
Net investment income (loss)	(22)	(33)	(46)	(70)
Other (income) expense	109	(215)	132	(204)
Amortization of purchased intangibles	51	54	101	109
Segment Income (loss)	(535)	20	(709)	(157)
Net Realized Gains Losses	30	(223)	(928)	(320)
Interest expense	128	140	260	280
Chubb integration expenses		4		7
Income tax benefit	(62)	208	153	396
Net income (loss)	$ (571)	$ (555)	$ (2,050)	$ (1,160)

Earnings Per Share (Detail)

Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income	$ (331)	$ 1,150	$ (79)	$ 2,190
Weighted-average shares outstanding	451,402,807	457,224,455	451,635,733	458,010,447
Share-based compensation plans	1,395,951	2,945,237	2,044,144	2,863,109
Weighted-average shares outstanding and assumed conversions	451,402,807	460,169,692	451,635,733	460,873,556
Basic earnings per share (US$ per share)	$ (0.73)	$ 2.52	$ (0.17)	$ 4.78
Diluted earnings per share (US$ per share)	$ (0.73)	$ 2.50	$ (0.17)	$ 4.75
Potential anti-dilutive share conversions	8,378,447	2,660,925	6,583,319	5,037,959

Information provided in conne_3

Information provided in connection with outstanding debt of subsidiaries Information provided in connection with outstanding debt of subsidiaries (Narrative) (Details)	Jun. 30, 2020
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]
Equity Method Investment, Ownership Percentage	100.00%

Information Provided In Conne_4

Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Balance Sheet) (Detail) - USD ($) $ in Millions		Jun. 30, 2020		Dec. 31, 2019		Jun. 30, 2019	Dec. 31, 2018
Condensed Balance Sheet Statements, Captions [Line Items]
Investments		$ 110,877		$ 109,234
Cash		1,557	[1]	1,537	[2]
Restricted cash		152		109
Insurance and reinsurance balances receivable		10,853		10,357
Reinsurance recoverable on losses and loss expenses		15,207		15,181
Reinsurance recoverable on policy benefits		197		197
Operating Lease, Right-of-Use Asset		483		551
Value of business acquired		290		306
Goodwill and other intangible assets		21,093		21,359
Investments in subsidiaries		0		0
Due from subsidiaries and affiliates, net		0		0
Other assets		21,248		18,663
Total assets		181,474		176,943
Unpaid losses and loss expenses		65,699		62,690		$ 63,205	$ 62,960
Unearned premiums		17,081		16,771
Future policy benefits		5,895		5,814
Due to subsidiaries and affiliates, net		0		0
Affiliated notional cash pooling programs		0
Operating Lease, Liability		531		603
Repurchase agreements		1,409		1,416
Short-term debt		1,300		1,299
Long-term debt		13,656		13,559
Trust preferred securities		308		308
Other liabilities		21,366		19,755
Total liabilities		126,714		121,612
Total shareholders' equity		54,760		55,331		$ 53,802
Total liabilities and shareholders’ equity		181,474		176,943
Chubb Limited (Parent Guarantor)
Condensed Balance Sheet Statements, Captions [Line Items]
Investments		0		0
Cash		1	[1]	2	[2]
Restricted cash		0		0
Insurance and reinsurance balances receivable		0		0
Reinsurance recoverable on losses and loss expenses		0		0
Reinsurance recoverable on policy benefits		0		0
Value of business acquired		0		0
Goodwill and other intangible assets		0		0
Investments in subsidiaries		52,339		50,853
Due from subsidiaries and affiliates, net		3,636		4,776
Other assets		8		12
Total assets		55,984		55,643
Unpaid losses and loss expenses		0		0
Unearned premiums		0		0
Future policy benefits		0		0
Due to subsidiaries and affiliates, net		0		0
Affiliated notional cash pooling programs	[1]	882
Repurchase agreements		0		0
Short-term debt		0		0
Long-term debt		0		0
Trust preferred securities		0		0
Other liabilities		342		312
Total liabilities		1,224		312
Total shareholders' equity		54,760		55,331
Total liabilities and shareholders’ equity		55,984		55,643
Chubb INA Holdings Inc (Subsidiary Issuer)
Condensed Balance Sheet Statements, Captions [Line Items]
Investments		195		1,013
Cash		0	[1]	442	[2]
Restricted cash		0		0
Insurance and reinsurance balances receivable		0		0
Reinsurance recoverable on losses and loss expenses		0		0
Reinsurance recoverable on policy benefits		0		0
Value of business acquired		0		0
Goodwill and other intangible assets		0		0
Investments in subsidiaries		52,752		52,076
Due from subsidiaries and affiliates, net		0		0
Other assets		336		408
Total assets		53,283		53,939
Unpaid losses and loss expenses		0		0
Unearned premiums		0		0
Future policy benefits		0		0
Due to subsidiaries and affiliates, net		3,365		4,446
Affiliated notional cash pooling programs	[1]	186
Repurchase agreements		0		0
Short-term debt		1,300		1,298
Long-term debt		13,656		13,559
Trust preferred securities		308		308
Other liabilities		1,415		1,649
Total liabilities		20,230		21,260
Total shareholders' equity		33,053		32,679
Total liabilities and shareholders’ equity		53,283		53,939
Other Chubb Limited Subsidiaries
Condensed Balance Sheet Statements, Captions [Line Items]
Investments		110,682		108,221
Cash		2,624	[1]	1,093	[2]
Restricted cash		152		109
Insurance and reinsurance balances receivable		13,637		12,920
Reinsurance recoverable on losses and loss expenses		24,804		24,780
Reinsurance recoverable on policy benefits		292		292
Value of business acquired		290		306
Goodwill and other intangible assets		21,093		21,359
Investments in subsidiaries		0		0
Due from subsidiaries and affiliates, net		0		0
Other assets		22,858		20,072
Total assets		196,432		189,152
Unpaid losses and loss expenses		75,013		71,916
Unearned premiums		18,301		17,978
Future policy benefits		5,990		5,909
Due to subsidiaries and affiliates, net		271		330
Affiliated notional cash pooling programs	[1]	0
Repurchase agreements		1,409		1,416
Short-term debt		0		1
Long-term debt		0		0
Trust preferred securities		0		0
Other liabilities		23,410		21,352
Total liabilities		124,394		118,902
Total shareholders' equity		72,038		70,250
Total liabilities and shareholders’ equity		196,432		189,152
Consolidating Adjustments and Eliminations
Condensed Balance Sheet Statements, Captions [Line Items]
Investments		0		0
Cash		(1,068)	[1]	0	[2]
Restricted cash		0		0
Insurance and reinsurance balances receivable		(2,784)		(2,563)
Reinsurance recoverable on losses and loss expenses		(9,597)		(9,599)
Reinsurance recoverable on policy benefits		(95)		(95)
Value of business acquired		0		0
Goodwill and other intangible assets		0		0
Investments in subsidiaries		(105,091)		(102,929)
Due from subsidiaries and affiliates, net		(3,636)		(4,776)
Other assets		(1,954)		(1,829)
Total assets		(124,225)		(121,791)
Unpaid losses and loss expenses		(9,314)		(9,226)
Unearned premiums		(1,220)		(1,207)
Future policy benefits		(95)		(95)
Due to subsidiaries and affiliates, net		(3,636)		(4,776)
Affiliated notional cash pooling programs	[1]	(1,068)
Repurchase agreements		0		0
Short-term debt		0		0
Long-term debt		0		0
Trust preferred securities		0		0
Other liabilities		(3,801)		(3,558)
Total liabilities		(19,134)		(18,862)
Total shareholders' equity		(105,091)		(102,929)
Total liabilities and shareholders’ equity		$ (124,225)		$ (121,791)
[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to the 2019 Form 10-K for additional information.

Information Provided In Conne_5

Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Operations) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Condensed Statement of Income Captions [Line Items]
Net premiums written	$ 8,355	$ 8,343	$ 16,332	$ 15,656
Net premiums earned	8,128	7,891	15,922	15,028
Net investment income	827	859	1,688	1,695
Equity In Earnings Of Subsidiaries	0	0	0	0
Net Realized Gains Losses	30	(223)	(928)	(320)
Losses and loss expenses	6,577	4,715	11,062	8,813
Policy benefits	223	161	352	357
Policy acquisition costs and administrative expenses	2,320	2,302	4,676	4,476
Interest (income) expense	128	140	260	280
Other (income) expense	58	(230)	113	(269)
Amortization of purchased intangibles	72	77	145	153
Chubb integration expenses	0	4	0	7
Income tax benefit	(62)	208	153	396
Net income (loss)	(331)	1,150	(79)	2,190
Comprehensive income (loss)	2,860	2,059	400	4,777
Chubb Limited (Parent Guarantor)
Condensed Statement of Income Captions [Line Items]
Net premiums written	0	0	0	0
Net premiums earned	0	0	0	0
Net investment income	0	1	(2)	2
Equity In Earnings Of Subsidiaries	(366)	1,104	(110)	2,094
Net Realized Gains Losses	23	4	2	5
Losses and loss expenses	0	0	0	0
Policy benefits	0	0	0	0
Policy acquisition costs and administrative expenses	21	22	45	42
Interest (income) expense	(35)	(62)	(69)	(128)
Other (income) expense	(8)	(6)	(17)	(12)
Amortization of purchased intangibles	0	0	0	0
Chubb integration expenses		0		0
Income tax benefit	10	5	10	9
Net income (loss)	(331)	1,150	(79)	2,190
Comprehensive income (loss)	2,860	2,059	400	4,777
Chubb INA Holdings Inc (Subsidiary Issuer)
Condensed Statement of Income Captions [Line Items]
Net premiums written	0	0	0	0
Net premiums earned	0	0	0	0
Net investment income	1	(6)	5	(10)
Equity In Earnings Of Subsidiaries	(271)	762	322	1,521
Net Realized Gains Losses	(192)	(21)	(79)	(34)
Losses and loss expenses	0	0	0	0
Policy benefits	0	0	0	0
Policy acquisition costs and administrative expenses	(30)	(5)	(68)	(20)
Interest (income) expense	149	180	297	365
Other (income) expense	(5)	1	3	4
Amortization of purchased intangibles	0	0	0	0
Chubb integration expenses		0		2
Income tax benefit	(66)	(45)	(59)	(87)
Net income (loss)	(510)	604	75	1,213
Comprehensive income (loss)	1,872	1,397	672	3,338
Other Chubb Limited Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net premiums written	8,355	8,343	16,332	15,656
Net premiums earned	8,128	7,891	15,922	15,028
Net investment income	826	864	1,685	1,703
Equity In Earnings Of Subsidiaries	0	0	0	0
Net Realized Gains Losses	199	(206)	(851)	(291)
Losses and loss expenses	6,577	4,715	11,062	8,813
Policy benefits	223	161	352	357
Policy acquisition costs and administrative expenses	2,329	2,285	4,699	4,454
Interest (income) expense	14	22	32	43
Other (income) expense	71	(225)	127	(261)
Amortization of purchased intangibles	72	77	145	153
Chubb integration expenses		4		5
Income tax benefit	(6)	248	202	474
Net income (loss)	(127)	1,262	137	2,402
Comprehensive income (loss)	3,078	2,181	660	4,969
Consolidating Adjustments and Eliminations
Condensed Statement of Income Captions [Line Items]
Net premiums written	0	0	0	0
Net premiums earned	0	0	0	0
Net investment income	0	0	0	0
Equity In Earnings Of Subsidiaries	637	(1,866)	(212)	(3,615)
Net Realized Gains Losses	0	0	0	0
Losses and loss expenses	0	0	0	0
Policy benefits	0	0	0	0
Policy acquisition costs and administrative expenses	0	0	0	0
Interest (income) expense	0	0	0	0
Other (income) expense	0	0	0	0
Amortization of purchased intangibles	0	0	0	0
Chubb integration expenses		0		0
Income tax benefit	0	0	0	0
Net income (loss)	637	(1,866)	(212)	(3,615)
Comprehensive income (loss)	$ (4,950)	$ (3,578)	$ (1,332)	$ (8,307)

Information Provided In Conne_6

Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Cash Flows) (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020		Jun. 30, 2019
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	$ 3,697		$ 2,708
Purchases of fixed maturities available for sale	(13,058)		(12,566)
Purchases of fixed maturities held to maturity	(42)		(73)
Purchases of equity securities	(2,824)		(147)
Proceeds From Sale Of Available For Sale Securities Debt Condensed	7,734		7,838
Sales of equity securities	1,353		266
Maturities and redemptions of fixed maturities available for sale	5,220		3,963
Maturities and redemptions of fixed maturities held to maturity	642		598
Net change in short-term investments	173		(763)
Net derivative instruments settlements	(18)		(536)
Private equity contribution	(546)		(920)
Private equity distribution	443		780
Payments for Other Deposits	(1,550)		0
Capital contribution	0		0
Other	(221)		(727)
Net cash flows used for investing activities	(2,694)		(2,287)
Dividends paid on Common Shares	(678)		(671)
Common Shares repurchased	(333)		(741)
Proceeds from Issuance of Long-term Debt	0		1,289
Repayments of Long-term Debt	0		(500)
Proceeds from issuance of repurchase agreements	1,402		1,984
Repayments of repurchase agreements	(1,402)		(1,986)
Proceeds from share-based compensation plans	74		95
Dividend to Parent Company	0		0
Advances (to) from affiliates	0		0
Capital contribution	0		0
Net proceeds from (payments to) affiliated notional cash pooling program	0	[1]	0	[2]
Policyholder contract deposits	215		237
Policyholder contract withdrawals	(173)		(138)
Proceeds from (Payments for) Other Financing Activities	(3)		0
Net cash flows used for financing activities	(898)		(431)
Effect of foreign currency rate changes on cash and restricted cash	(42)		38
Net Increase (Decrease) in cash and restricted cash	63		28
Cash and restricted cash - beginning of period	1,646	[1]	1,340	[2]
Cash and restricted cash - end of period	1,709	[1]	1,368	[2]
Chubb Limited (Parent Guarantor)
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	181		323
Purchases of fixed maturities available for sale	0		0
Purchases of fixed maturities held to maturity	0		0
Purchases of equity securities	0		0
Proceeds From Sale Of Available For Sale Securities Debt Condensed	0		0
Sales of equity securities	0		0
Maturities and redemptions of fixed maturities available for sale	0		0
Maturities and redemptions of fixed maturities held to maturity	0		0
Net change in short-term investments	0		0
Net derivative instruments settlements	0		0
Private equity contribution	0		0
Private equity distribution	0		0
Payments for Other Deposits	0
Capital contribution	(1,200)		(600)
Other	(1)		0
Net cash flows used for investing activities	(1,201)		(600)
Dividends paid on Common Shares	(678)		(671)
Common Shares repurchased	(333)		0
Proceeds from Issuance of Long-term Debt			0
Repayments of Long-term Debt			0
Proceeds from issuance of repurchase agreements	0		0
Repayments of repurchase agreements	0		0
Proceeds from share-based compensation plans	0		0
Dividend to Parent Company	0		0
Advances (to) from affiliates	1,149		801
Capital contribution	0		0
Net proceeds from (payments to) affiliated notional cash pooling program	882	[1]	142	[2]
Policyholder contract deposits	0		0
Policyholder contract withdrawals	0		0
Proceeds from (Payments for) Other Financing Activities	0		0
Net cash flows used for financing activities	1,020		272
Effect of foreign currency rate changes on cash and restricted cash	(1)		5
Net Increase (Decrease) in cash and restricted cash	(1)		0
Cash and restricted cash - beginning of period	2	[1]	1	[2]
Cash and restricted cash - end of period	1	[1]	1	[2]
Chubb INA Holdings Inc (Subsidiary Issuer)
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	(307)		1,302
Purchases of fixed maturities available for sale	(13)		(5)
Purchases of fixed maturities held to maturity	0		0
Purchases of equity securities	0		0
Proceeds From Sale Of Available For Sale Securities Debt Condensed	7		0
Sales of equity securities	0		0
Maturities and redemptions of fixed maturities available for sale	29		16
Maturities and redemptions of fixed maturities held to maturity	0		0
Net change in short-term investments	761		(11)
Net derivative instruments settlements	69		(35)
Private equity contribution	0		0
Private equity distribution	0		0
Payments for Other Deposits	0
Capital contribution	0		(110)
Other	(3)		(12)
Net cash flows used for investing activities	850		(157)
Dividends paid on Common Shares	0		0
Common Shares repurchased	0		0
Proceeds from Issuance of Long-term Debt			1,289
Repayments of Long-term Debt			(500)
Proceeds from issuance of repurchase agreements	0		0
Repayments of repurchase agreements	0		0
Proceeds from share-based compensation plans	0		0
Dividend to Parent Company	0		0
Advances (to) from affiliates	(1,168)		(1,498)
Capital contribution	0		0
Net proceeds from (payments to) affiliated notional cash pooling program	186	[1]	(437)	[2]
Policyholder contract deposits	0		0
Policyholder contract withdrawals	0		0
Proceeds from (Payments for) Other Financing Activities	(3)		0
Net cash flows used for financing activities	(985)		(1,146)
Effect of foreign currency rate changes on cash and restricted cash	0		0
Net Increase (Decrease) in cash and restricted cash	(442)		(1)
Cash and restricted cash - beginning of period	442	[1]	2	[2]
Cash and restricted cash - end of period	0	[1]	1	[2]
Other Chubb Limited Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	3,933		2,943
Purchases of fixed maturities available for sale	(13,045)		(12,561)
Purchases of fixed maturities held to maturity	(42)		(73)
Purchases of equity securities	(2,824)		(147)
Proceeds From Sale Of Available For Sale Securities Debt Condensed	7,727		7,838
Sales of equity securities	1,353		266
Maturities and redemptions of fixed maturities available for sale	5,191		3,947
Maturities and redemptions of fixed maturities held to maturity	642		598
Net change in short-term investments	(588)		(752)
Net derivative instruments settlements	(87)		(501)
Private equity contribution	(546)		(920)
Private equity distribution	443		780
Payments for Other Deposits	(1,550)
Capital contribution	0		0
Other	(217)		(715)
Net cash flows used for investing activities	(3,543)		(2,240)
Dividends paid on Common Shares	0		0
Common Shares repurchased	0		(741)
Proceeds from Issuance of Long-term Debt			0
Repayments of Long-term Debt			0
Proceeds from issuance of repurchase agreements	1,402		1,984
Repayments of repurchase agreements	(1,402)		(1,986)
Proceeds from share-based compensation plans	74		95
Dividend to Parent Company	(110)		(1,860)
Advances (to) from affiliates	19		697
Capital contribution	1,200		710
Net proceeds from (payments to) affiliated notional cash pooling program	0	[1]	0	[2]
Policyholder contract deposits	215		237
Policyholder contract withdrawals	(173)		(138)
Proceeds from (Payments for) Other Financing Activities	0		0
Net cash flows used for financing activities	1,225		(1,002)
Effect of foreign currency rate changes on cash and restricted cash	(41)		33
Net Increase (Decrease) in cash and restricted cash	1,574		(266)
Cash and restricted cash - beginning of period	1,202	[1]	1,989	[2]
Cash and restricted cash - end of period	2,776	[1]	1,723	[2]
Consolidation, Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	(110)		(1,860)
Purchases of fixed maturities available for sale	0		0
Purchases of fixed maturities held to maturity	0		0
Purchases of equity securities	0		0
Proceeds From Sale Of Available For Sale Securities Debt Condensed	0		0
Sales of equity securities	0		0
Maturities and redemptions of fixed maturities available for sale	0		0
Maturities and redemptions of fixed maturities held to maturity	0		0
Net change in short-term investments	0		0
Net derivative instruments settlements	0		0
Private equity contribution	0		0
Private equity distribution	0		0
Payments for Other Deposits	0
Capital contribution	1,200		710
Other	0		0
Net cash flows used for investing activities	1,200		710
Dividends paid on Common Shares	0		0
Common Shares repurchased	0		0
Proceeds from Issuance of Long-term Debt			0
Repayments of Long-term Debt			0
Proceeds from issuance of repurchase agreements	0		0
Repayments of repurchase agreements	0		0
Proceeds from share-based compensation plans	0		0
Dividend to Parent Company	110		1,860
Advances (to) from affiliates	0		0
Capital contribution	(1,200)		(710)
Net proceeds from (payments to) affiliated notional cash pooling program	(1,068)	[1]	295	[2]
Policyholder contract deposits	0		0
Policyholder contract withdrawals	0		0
Proceeds from (Payments for) Other Financing Activities	0		0
Net cash flows used for financing activities	(2,158)		1,445
Effect of foreign currency rate changes on cash and restricted cash	0		0
Net Increase (Decrease) in cash and restricted cash	(1,068)		295
Cash and restricted cash - beginning of period	0	[1]	(652)	[2]
Cash and restricted cash - end of period	$ (1,068)	[1]	$ (357)	[2]
[1]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2020 and December 31, 2019, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various Chubb entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual Chubb accounts are translated daily into a single currency and pooled on a notional basis. Individual Chubb entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2019 and December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.