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
	Mar. 31, 2023	Mar. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	$ 55	$ 136
Net realized gains (losses), liabilities	$ 1,531	$ (3,693)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Revenues	Revenues
Policyholder contract deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	$ 381	$ (658)
Policyholder contract deposits | Net investment income - excluding Fortitude Re funds withheld assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	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	381	(658)
Policyholder contract deposits | Change in the fair value of market risk benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	0
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
Market Risk Benefit Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	87	(702)
Market Risk Benefit Liabilities | Net investment income - excluding Fortitude Re funds withheld assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	0
Market Risk Benefit Liabilities | Net realized gains/(losses)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	(3)
Market Risk Benefit Liabilities | Change in the fair value of market risk benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	87	(699)
Market Risk Benefit Liabilities | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	0
Derivative liabilities, net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	(15)	283
Derivative liabilities, net | Net investment income - excluding Fortitude Re funds withheld assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	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	(88)	327
Derivative liabilities, net | Change in the fair value of market risk benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	89	(29)
Derivative liabilities, net | Other Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	(16)	(15)
Fortitude Re funds withheld payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	1,165	(3,318)
Fortitude Re funds withheld payable | Net investment income - excluding Fortitude Re funds withheld assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	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	1,165	(3,318)
Fortitude Re funds withheld payable | Change in the fair value of market risk benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), liabilities	0	0
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
Bonds available for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	66	145
Bonds available for sale | Net investment income - excluding Fortitude Re funds withheld assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	62	164
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	4	(19)
Bonds available for sale | Change in the fair value of market risk benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	0	0
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
Other bond securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	41	(121)
Other bond securities | Net investment income - excluding Fortitude Re funds withheld assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	41	(121)
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
Other bond securities | Change in the fair value of market risk benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	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
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	0	0
Other invested assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	(52)	112
Other invested assets | Net investment income - excluding Fortitude Re funds withheld assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	(51)	112
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	(1)	0
Other invested assets | Change in the fair value of market risk benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net realized gains (losses), assets	0	0
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