Investments (Supplemental Net Investment Gains (Losses)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Net Investment Income [Line Items]
Changes in estimated fair value subsequent to purchase of equity securities still held at the end of the respective periods and recognized in net investment gains (losses)	$ (58)	$ (14)	$ (47)	$ 44
Realized gains (losses) on investments sold or disposed	(39)	(281)	(369)	(847)
Foreign currency gains (losses)	170	(21)	5	(7)
Net realized investment gains (losses) from sales and disposals of investments	26	(234)	(170)	(721)
Net investment income
Net Investment Income [Line Items]
Net realized investment gains (losses) from sales and disposals of investments	65	47	199	126
Cash Flow Hedging
Net Investment Income [Line Items]
Realized gains (losses) on investments sold or disposed	0	2	0	(20)
Equity Securities
Net Investment Income [Line Items]
Changes in estimated fair value subsequent to purchase of equity securities still held at the end of the respective periods and recognized in net investment gains (losses)	$ (36)	$ (10)	$ (23)	$ 9