Reinsurance - Summary of the Impact of Funds Withheld (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Effects of Reinsurance [Line Items]
Total net investment income	$ 3,904	$ 3,533
Net realized gains (losses)	(424)	(1,909)
Income (loss) from continuing operations before income tax expense (benefit)	2,051	(231)
Income tax expense (benefit)	451	(144)
Net income (loss)	1,600	(87)
Change in unrealized depreciation of all other investments	(403)	112
Comprehensive income (loss)	543	3,826
Fortitude Re funds withheld assets
Effects of Reinsurance [Line Items]
Total net investment income	369	446
Fortitude Holdings
Effects of Reinsurance [Line Items]
Total net investment income	369	446
Net realized gains (losses)	(166)	(1,196)
Income (loss) from continuing operations before income tax expense (benefit)	203	(750)
Income tax expense (benefit)	43	(158)
Net income (loss)	160	(592)
Comprehensive income (loss)	32	(36)
Fortitude Holdings | Fortitude Re funds withheld assets
Effects of Reinsurance [Line Items]
Net realized gains (losses)	(179)	(31)
Fortitude Holdings | Fortitude Re funds withheld assets | Embedded derivatives
Effects of Reinsurance [Line Items]
Net realized gains (losses)	13	(1,165)
Fortitude Holdings | Other investments
Effects of Reinsurance [Line Items]
Change in unrealized depreciation of all other investments	$ (128)	$ 556