Fair Value Measurements - Assets measured at fair value on a non-recurring basis and related impairment charges (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets	[1]	$ 16,217	$ 15,953
Impairment Charges		90	26	$ 46
Fair value on a non-recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other invested assets		80	12
Other assets		0
Total(d)		80	12
Impairment Charges		134	26	73
Fair value on a non-recurring basis | Other investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment Charges		13	25	6
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		121	1	$ 67
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
Other assets		0
Total(d)		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
Other assets		0
Total(d)		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		80	12
Other assets		0
Total(d)		$ 80	$ 12

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