Reinsurance - Summary of the impact of funds withheld (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Effects of Reinsurance [Line Items]
Total net investment income	$ 3,533	$ 3,237
Total net realized gains (losses)	(1,909)	3,579
Income (loss) from continuing operations before income tax expense (benefit)	(231)	5,714
Income tax expense (benefit)	(144)	1,154
Net income (loss)	(87)	4,560
Change in unrealized depreciation of all other investments	112	873
Comprehensive income (loss)	3,826	(8,551)
Fortitude Re funds withheld assets
Effects of Reinsurance [Line Items]
Total net investment income	446	291
Fortitude Holdings
Effects of Reinsurance [Line Items]
Total net investment income	446	291
Total net realized gains (losses)	(1,196)	3,178
Income (loss) from continuing operations before income tax expense (benefit)	(750)	3,469
Income tax expense (benefit)	(158)	728
Net income (loss)	(592)	2,741
Comprehensive income (loss)	(36)	103
Fortitude Holdings | Fortitude Re funds withheld assets
Effects of Reinsurance [Line Items]
Total net realized gains (losses)	(31)	(140)
Fortitude Holdings | Fortitude Re funds withheld assets | Embedded derivatives
Effects of Reinsurance [Line Items]
Total net realized gains (losses)	(1,165)	3,318
Fortitude Holdings | Other investments
Effects of Reinsurance [Line Items]
Change in unrealized depreciation of all other investments	$ 556	$ (2,638)