Investments (Supplemental Net Investment Gains (Losses)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Net Investment Income [Line Items]
Equity Securities, FV-NI, Unrealized Gain (Loss)	$ 17	$ (42)	$ 58	$ (62)
Realized gains (losses) on investments sold or disposed	(20)	(445)	(566)	(656)
Foreign Currency Transaction Gain (Loss), Realized	(27)	(134)	14	(11)
Debt and Equity Securities, Realized Gain (Loss)	21	(405)	(487)	(547)
Net investment income
Net Investment Income [Line Items]
Debt and Equity Securities, Realized Gain (Loss)	41	40	79	109
Cash Flow Hedging [Member]
Net Investment Income [Line Items]
Realized gains (losses) on investments sold or disposed	(27)	42	(22)	60
Equity Securities
Net Investment Income [Line Items]
Equity Securities, FV-NI, Unrealized Gain (Loss)	$ 31	$ (40)	$ 20	$ (62)