Reinsurance - Summary of the composition of pool of assets (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022		Jan. 01, 2021
Effects of Reinsurance [Line Items]
Bonds available for sale	[1]	$ 231,733		$ 226,156
Fixed maturity securities - fair value option	[1]	5,241		4,485
Investment real estate		2,237		2,153
Fair Value Using NAV Per Share (or its equivalent)		11,320		11,809
Short-term investments	[1]	17,200		12,376
Other assets		13,089	[1]	12,384	[1]	$ 13,520
Total assets		539,306		522,228		$ 598,841
Carrying Value
Effects of Reinsurance [Line Items]
Short-term investments		6,428		6,668
Other assets		45		33
Commercial mortgage loans
Effects of Reinsurance [Line Items]
Loans		38,009		37,128
Policy loans
Effects of Reinsurance [Line Items]
Loans		1,753		1,758
Fortitude Holdings
Effects of Reinsurance [Line Items]
Change in net unrealized gains (losses), gross		734		(7,500)
Change in net unrealized gains (losses), net of tax		580		(5,900)
Derivative asset, Fair value of collateral		63		192
Derivative liability, Fair value of collateral		34		28
Fortitude Holdings | Carrying Value
Effects of Reinsurance [Line Items]
Bonds available for sale		17,384		18,821
Fixed maturity securities - fair value option		4,867		4,182
Investment real estate		184		133
Fair Value Using NAV Per Share (or its equivalent)		1,910		1,893
Short-term investments		176		75
Funds withheld investment assets		28,772		29,566
Derivative assets, net		45		90
Other assets		758		782
Total assets		29,575		30,438
Fortitude Holdings | Estimated Fair Value
Effects of Reinsurance [Line Items]
Bonds available for sale		17,384		18,821
Fixed maturity securities - fair value option		4,867		4,182
Investment real estate		329		348
Fair Value Using NAV Per Share (or its equivalent)		1,910		1,893
Short-term investments		176		75
Funds withheld investment assets		28,681		29,511
Derivative assets, net		45		90
Other assets		758		782
Total(d)		29,484		30,383
Fortitude Holdings | Commercial mortgage loans | Carrying Value
Effects of Reinsurance [Line Items]
Loans		3,921		4,107
Fortitude Holdings | Commercial mortgage loans | Estimated Fair Value
Effects of Reinsurance [Line Items]
Loans, fair value		3,685		3,837
Fortitude Holdings | Policy loans | Carrying Value
Effects of Reinsurance [Line Items]
Loans		330		355
Fortitude Holdings | Policy loans | Estimated Fair Value
Effects of Reinsurance [Line Items]
Loans, fair value		$ 330		$ 355

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