Reinsurance - Summary of the composition of pool of assets (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2023		Sep. 30, 2022	Dec. 31, 2022		Jan. 01, 2021
Effects of Reinsurance [Line Items]
Bonds available for sale	[1]	$ 214,940			$ 226,156
Fixed maturity securities - fair value option	[1]	4,840			4,485
Investment real estate		2,208			2,153
Short-term investments	[1]	13,048			12,376
Other assets		11,857	[1]		12,384	[1]	$ 13,520
Total assets		521,521			522,228		$ 598,841
Carrying Value
Effects of Reinsurance [Line Items]
Short-term investments		6,589			6,668
Other assets		36			33
Hedge Funds and Private Equity Funds
Effects of Reinsurance [Line Items]
Fair Value Using NAV Per Share (or its equivalent)		11,643			11,809
Commercial mortgage loans
Effects of Reinsurance [Line Items]
Loans		37,996			37,128
Policy loans
Effects of Reinsurance [Line Items]
Loans		1,768			1,758
Fortitude Holdings
Effects of Reinsurance [Line Items]
Change in net unrealized gains (losses), gross		(740)		$ (7,700)
Change in net unrealized gains (losses), net of tax		(585)		$ (6,100)
Derivative asset, Fair value of collateral		18			192
Derivative liability, Fair value of collateral		27			28
Fortitude Holdings | Carrying Value
Effects of Reinsurance [Line Items]
Bonds available for sale		15,955			18,821
Fixed maturity securities - fair value option		4,418			4,182
Investment real estate		122			133
Short-term investments		152			75
Funds withheld investment assets		26,967			29,566
Derivative assets, net		2			90
Other assets		856			782
Total assets		27,825			30,438
Fortitude Holdings | Estimated Fair Value
Effects of Reinsurance [Line Items]
Bonds available for sale		15,955			18,821
Fixed maturity securities - fair value option		4,418			4,182
Investment real estate		295			348
Short-term investments		152			75
Funds withheld investment assets		26,833			29,511
Derivative assets, net		2			90
Other assets		856			782
Total(d)		27,691			30,383
Fortitude Holdings | Hedge Funds and Private Equity Funds | Carrying Value
Effects of Reinsurance [Line Items]
Fair Value Using NAV Per Share (or its equivalent)		1,856			1,893
Fortitude Holdings | Hedge Funds and Private Equity Funds | Estimated Fair Value
Effects of Reinsurance [Line Items]
Fair Value Using NAV Per Share (or its equivalent)		1,856			1,893
Fortitude Holdings | Commercial mortgage loans | Carrying Value
Effects of Reinsurance [Line Items]
Loans		4,129			4,107
Fortitude Holdings | Commercial mortgage loans | Estimated Fair Value
Effects of Reinsurance [Line Items]
Loans, fair value		3,822			3,837
Fortitude Holdings | Policy loans | Carrying Value
Effects of Reinsurance [Line Items]
Loans		335			355
Fortitude Holdings | Policy loans | Estimated Fair Value
Effects of Reinsurance [Line Items]
Loans, fair value		$ 335			$ 355

[1] See Note 10 for details of balances associated with variable interest entities.