Investments (Supplemental Net Investment Gains (Losses)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Investment Income [Line Items]
Equity Securities, FV-NI, Unrealized Gain (Loss)	$ 60	$ (86)	$ 177
Realized gains (losses) on investments sold or disposed	(1,028)	(880)	711
Gains (losses) on leveraged leases and renewable energy partnerships	24	33	12
Foreign Currency Transaction Gain (Loss), Realized	52	183	(9)
Debt and Equity Securities, Realized Gain (Loss)	(821)	(725)	1,229
Cash Flow Hedging [Member]
Net Investment Income [Line Items]
Realized gains (losses) on investments sold or disposed	(7)	38	88
Equity Securities
Net Investment Income [Line Items]
Equity Securities, FV-NI, Unrealized Gain (Loss)	$ 22	$ (89)	$ 77