Investments - Components of net investment income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Net Investment Income [Line Items]
Total investment income	$ 3,774	$ 2,777	$ 7,512	$ 6,169
Investment expenses	203	173	408	328
Net investment income	3,571	2,604	7,104	5,841
Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	3,477	2,580	6,760	5,672
Investment expenses	197	164	393	310
Net investment income	3,280	2,416	6,367	5,362
Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	297	197	752	497
Investment expenses	6	9	15	18
Net investment income	291	188	737	479
Available for sale fixed maturity securities, including short-term investments
Net Investment Income [Line Items]
Total investment income	2,861	2,414	5,650	4,756
Available for sale fixed maturity securities, including short-term investments | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	2,629	2,147	5,175	4,188
Available for sale fixed maturity securities, including short-term investments | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	232	267	475	568
Other fixed maturity securities
Net Investment Income [Line Items]
Total investment income	1	(355)	136	(674)
Gains/(losses) recognized in earnings on hedging derivatives		(55)		(151)
Other fixed maturity securities | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	8	(175)	20	(376)
Other fixed maturity securities | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	(7)	(180)	116	(298)
Equity securities
Net Investment Income [Line Items]
Total investment income	43	(30)	94	(57)
Equity securities | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	43	(30)	94	(57)
Equity securities | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	0	0	0	0
Interest on mortgage and other loans
Net Investment Income [Line Items]
Total investment income	683	511	1,309	1,010
Interest on mortgage and other loans | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	625	460	1,192	913
Interest on mortgage and other loans | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	58	51	117	97
Alternative investments
Net Investment Income [Line Items]
Total investment income	160	165	267	905
Alternative investments | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	147	109	223	778
Alternative investments | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	13	56	44	127
Real estate
Net Investment Income [Line Items]
Total investment income	17	32	20	32
Real estate | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	17	32	20	32
Real estate | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	0	0	0	0
Other investments
Net Investment Income [Line Items]
Total investment income	9	40	36	197
Gains/(losses) recognized in earnings on hedging derivatives	(1)	41	(4)	132
Other investments | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	8	37	36	194
Other investments | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	$ 1	$ 3	$ 0	$ 3