Reinsurance - Summary of the impact of funds withheld (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Effects of Reinsurance [Line Items]
Total net investment income	$ 3,556	$ 2,668	$ 10,660	$ 8,509
Total net realized gains (losses)	1,081	2,572	(1,125)	8,783
Income (loss) from continuing operations before income tax expense (benefit)	3,568	3,904	5,204	13,543
Income tax expense (benefit)	821	817	853	2,816
Net income (loss)	2,747	3,087	4,351	10,726
Change in unrealized depreciation of all other investments			(795)	171
Comprehensive income (loss)	(2,171)	(5,219)	1,608	(23,308)
Fortitude Re funds withheld assets
Effects of Reinsurance [Line Items]
Total net investment income	264	155	1,001	634
Fortitude Holdings
Effects of Reinsurance [Line Items]
Total net investment income	264	155	1,001	634
Total net realized gains (losses)	910	1,671	(244)	7,539
Income (loss) from continuing operations before income tax expense (benefit)	1,174	1,826	757	8,173
Income tax expense (benefit)	247	383	159	1,716
Net income (loss)	927	1,443	598	6,457
Comprehensive income (loss)	45	126	13	346
Fortitude Holdings | Fortitude Re funds withheld assets
Effects of Reinsurance [Line Items]
Total net realized gains (losses)	(227)	(86)	(396)	(312)
Fortitude Holdings | Fortitude Re funds withheld assets | Embedded derivatives
Effects of Reinsurance [Line Items]
Total net realized gains (losses)	1,137	1,757	152	7,851
Fortitude Holdings | Other investments
Effects of Reinsurance [Line Items]
Change in unrealized depreciation of all other investments	$ (882)	$ (1,317)	$ (585)	$ (6,111)