Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 387	$ 333	$ 796
Other comprehensive income (loss), before tax:
Change in current discount rate	16	41	39
Unrealized gains (losses) on securities	661	(4,635)	(1,303)
Pension and other postretirement benefits liability			1
Other comprehensive income (loss), before tax	677	(4,594)	(1,264)
Income tax expense (benefit) related to items of other comprehensive income (loss)	141	(965)	(265)
Other comprehensive income (loss), after tax	536	(3,629)	(999)
Comprehensive income (loss)	$ 923	$ (3,296)	$ (203)