Consolidated Statements of Operations and Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income tax expense (benefit)	$ 36	$ 0	$ 41
Reclassification out of Accumulated Other Comprehensive Income [Member] | AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Net realized gains (losses)	(281)	(31)	(302)
Income tax expense (benefit)	$ (36)	$ 0	$ (41)