Fair Value Measurements - Assets measured at fair value on a non-recurring basis and related impairment charges (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	[1]	$ 16,054		$ 16,054		$ 15,953
Impairment Charges				35	$ 12
Fair value on a non-recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		46		46		12
Other assets		0		0
Total(d)		46		46		12
Impairment Charges		41	$ 11	58	11
Fair value on a non-recurring basis | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment Charges		9	11	9	11
Fair value on a non-recurring basis | Asset Class to Loans Held For Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total(d)						163
Fair value on a non-recurring basis | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment Charges		32	$ 0	49	$ 0
Fair value on a non-recurring basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		0		0		0
Other assets		0		0
Total(d)		0		0		0
Fair value on a non-recurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		0		0		0
Other assets		0		0
Total(d)		0		0		0
Fair value on a non-recurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		46		46		12
Other assets		0		0
Total(d)		$ 46		$ 46		$ 12

[1] See Note 10 for details of balances associated with variable interest entities.