Investments - Components of net investment income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Net Investment Income [Line Items]
Total investment income	$ 3,738	$ 3,392
Investment expenses	205	155
Net investment income	3,533	3,237
Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	3,283	3,092
Investment expenses	196	146
Net investment income	3,087	2,946
Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	455	300
Investment expenses	9	9
Net investment income	446	291
Available for sale fixed maturity securities, including short-term investments
Net Investment Income [Line Items]
Total investment income	2,789	2,342
Available for sale fixed maturity securities, including short-term investments | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	2,546	2,041
Available for sale fixed maturity securities, including short-term investments | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	243	301
Other fixed maturity securities
Net Investment Income [Line Items]
Total investment income	135	(319)
Gains/(losses) recognized in earnings on hedging derivatives		(95)
Other fixed maturity securities | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	12	(201)
Other fixed maturity securities | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	123	(118)
Equity securities
Net Investment Income [Line Items]
Total investment income	51	(27)
Equity securities | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	51	(27)
Equity securities | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	0	0
Interest on mortgage and other loans
Net Investment Income [Line Items]
Total investment income	626	499
Interest on mortgage and other loans | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	567	453
Interest on mortgage and other loans | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	59	46
Alternative investments
Net Investment Income [Line Items]
Total investment income	107	740
Alternative investments | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	76	669
Alternative investments | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	31	71
Real estate
Net Investment Income [Line Items]
Total investment income	3	0
Real estate | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	3	0
Real estate | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	0	0
Other investments
Net Investment Income [Line Items]
Total investment income	27	157
Gains/(losses) recognized in earnings on hedging derivatives	(3)	91
Other investments | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	28	157
Other investments | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	$ (1)	$ 0