Investments - Components of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net Investment Income [Line Items]
Total investment income	$ 4,126	$ 3,738
Investment expenses	222	205
Net investment income	3,904	3,533
Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	3,749	3,283
Investment expenses	214	196
Net investment income	3,535	3,087
Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	377	455
Investment expenses	8	9
Net investment income	369	446
Available for sale fixed maturity securities, including short-term investments
Net Investment Income [Line Items]
Total investment income	3,162	2,789
Available for sale fixed maturity securities, including short-term investments | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	2,946	2,546
Available for sale fixed maturity securities, including short-term investments | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	216	243
Other fixed maturity securities
Net Investment Income [Line Items]
Total investment income	80	135
Other fixed maturity securities | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	9	12
Other fixed maturity securities | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	71	123
Equity securities
Net Investment Income [Line Items]
Total investment income	99	51
Equity securities | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	99	51
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	706	626
Interest on mortgage and other loans | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	649	567
Interest on mortgage and other loans | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	57	59
Alternative investments
Net Investment Income [Line Items]
Total investment income	41	107
Alternative investments | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	8	76
Alternative investments | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	33	31
Real estate
Net Investment Income [Line Items]
Total investment income	(2)	3
Real estate | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	5	3
Real estate | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	(7)	0
Other investments
Net Investment Income [Line Items]
Total investment income	40	27
Other investments | Excluding Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	33	28
Other investments | Fortitude Re Funds Withheld Assets
Net Investment Income [Line Items]
Total investment income	$ 7	$ (1)