Fair Value Measurements - Net realized and unrealized gains and losses included in income related to Level 3 assets and liabilities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	$ 65	$ 335	$ 201	$ 673
Net realized gains (losses), liabilities	(4,009)	3,332	(8,841)	(1,347)
Policyholder contract deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	(1,322)	1,363	(3,119)	(897)
Policyholder contract deposits | Net investment income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	0	0	0
Policyholder contract deposits | Net realized gains/(losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	(1,322)	1,363	(3,119)	(897)
Policyholder contract deposits | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	0	0	0
Derivative liabilities, net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	89	(87)	372	(124)
Derivative liabilities, net | Net investment income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	0	0	0
Derivative liabilities, net | Net realized gains/(losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	102	(72)	400	(95)
Derivative liabilities, net | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	(13)	(15)	(28)	(29)
Fortitude Re funds withheld payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	(2,776)	2,056	(6,094)	(326)
Fortitude Re funds withheld payable | Net investment income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	0	0	0
Fortitude Re funds withheld payable | Net realized gains/(losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	(2,776)	2,056	(6,094)	(326)
Fortitude Re funds withheld payable | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	0	0	0
Bonds available for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	85	175	230	369
Bonds available for sale | Net investment income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	142	163	306	348
Bonds available for sale | Net realized gains/(losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	(57)	12	(76)	21
Bonds available for sale | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	0	0	0	0
Other bond securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	(153)	46	(274)	37
Other bond securities | Net investment income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	(153)	46	(274)	37
Other bond securities | Net realized gains/(losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	0	0	0	0
Other bond securities | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	0	0	0	0
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	0	0	0	11
Equity securities | Net investment income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets				11
Equity securities | Net realized gains/(losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets				0
Equity securities | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets				0
Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	133	114	245	256
Other invested assets | Net investment income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	133	99	245	241
Other invested assets | Net realized gains/(losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	0	15	0	15
Other invested assets | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	$ 0	$ 0	$ 0	$ 0