Consolidated Statements Of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Cash flows from operating activities
Net income		$ 3,533		$ 4,454		$ 3,962
Adjustments to reconcile net income to net cash flows from operating activities
Net Realized Gains Losses		498		530		652
Amortization of premiums/discounts on fixed maturities		367		395		592
Amortization of purchased intangibles		290		305		339
Deferred income taxes		(333)		(97)		16
Unpaid losses and loss expenses		4,664		(257)		570
Unearned premiums		846		1,051		654
Future policy benefits		236		215		235
Insurance and reinsurance balances payable		535		(302)		722
Accounts payable, accrued expenses, and other liabilities		(98)		(207)		375
Income taxes payable		46		(7)		161
Insurance and reinsurance balances receivable		(114)		(270)		(981)
Reinsurance recoverable		(336)		838		(1,165)
Deferred policy acquisition costs		(89)		(344)		(301)
Other		(260)		38		(351)
Net cash flows from operating activities		9,785		6,342		5,480
Cash flows from investing activities
Purchases of fixed maturities available for sale		(26,298)		(25,846)		(24,700)
Purchases of to be announced mortgage-backed securities		0		0		(35)
Purchases of fixed maturities held to maturity		(202)		(229)		(456)
Purchases of equity securities		(6,419)		(531)		(207)
Sales of fixed maturities available for sale		11,377		13,110		14,001
Sales of to be announced mortgage-backed securities		0		6		29
Sales of equity securities		3,880		611		315
Maturities and redemptions of fixed maturities available for sale		12,450		9,039		7,352
Maturities and redemptions of fixed maturities held to maturity		995		946		1,124
Net change in short-term investments		(81)		(1,117)		516
Net derivative instruments settlements		(113)		(703)		16
Private equity contributions		(1,924)		(1,315)		(1,337)
Private equity distributions		907		1,390		980
Acquisition of subsidiaries (net of cash acquired of nil, $45, and nil)		0		(29)		0
Payment, including deposit, for Huatai Group Interest		(1,623)		(580)
Other		(470)		(657)		(533)
Net Cash Provided by (Used in) Investing Activities		(7,521)		(5,905)		(2,935)
Cash flows from financing activities
Dividends paid on Common Shares		(1,388)		(1,354)		(1,337)
Common Shares repurchased		(523)		(1,530)		(1,044)
Proceeds from issuance of long-term debt		988		2,828		2,171
Proceeds from issuance of repurchase agreements		2,354		2,817		2,029
Repayments of Long-term Debt		(1,301)		(510)		(2,001)
Repayment of repurchase agreements		(2,354)		(2,817)		(2,019)
Proceeds from share-based compensation plans		145		204		115
Policyholder contract deposits		470		514		453
Policyholder contract withdrawals		(386)		(303)		(358)
Other		(87)		0		0
Net cash flows (used for) from financing activities		(2,082)		(151)		(1,991)
Effect of foreign currency rate changes on cash and restricted cash		8		20		(65)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect		190		306		489
Cash and restricted cash - beginning of year		1,646	[1],[2]	1,340	[2],[3]	851	[3]
Cash and restricted cash - end of year	[2]	1,836		1,646	[1]	1,340	[3]
Supplemental cash flow information
Taxes paid		902		912		503
Interest paid		524		512		621
Cash Acquired from Acquisition		0		45		0
CHINA | Huatai Group [Member]
Cash flows from investing activities
Payment, including deposit, for Huatai Group Interest		$ (1,623)		$ (580)		$ 0

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

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

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