Reinsurance - Summary of the impact of funds withheld (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Effects of Reinsurance [Line Items]
Total net investment income	$ 14,592	$ 11,767	$ 14,612
Total net realized gains (losses)	(4,608)	7,064	2,271
Income from continuing operations before income tax expense (benefit)	3,858	14,299	13,347
Income tax expense (benefit)	(20)	3,025	2,441
Net income	3,878	11,273	10,906
Change in unrealized depreciation of all other investments	(1,674)	(1,094)	873
Comprehensive income (loss)	9,818	(21,030)	5,482
Fortitude Re funds withheld assets
Effects of Reinsurance [Line Items]
Total net investment income	1,544	943	1,971
Fortitude Holdings
Effects of Reinsurance [Line Items]
Total net investment income	1,544	943	1,971
Total net realized gains (losses)	(2,302)	6,995	400
Income from continuing operations before income tax expense (benefit)	(758)	7,938	2,371
Income tax expense (benefit)	(159)	1,667	499
Net income	(599)	6,271	1,872
Comprehensive income (loss)	(19)	371	112
Fortitude Holdings | Fortitude Re funds withheld assets
Effects of Reinsurance [Line Items]
Total net realized gains (losses)	(295)	(486)	1,003
Fortitude Holdings | Fortitude Re funds withheld assets | Embedded derivatives
Effects of Reinsurance [Line Items]
Total net realized gains (losses)	(2,007)	7,481	(603)
Fortitude Holdings | Other investments
Effects of Reinsurance [Line Items]
Change in unrealized depreciation of all other investments	$ 580	$ (5,900)	$ (1,760)