Condensed Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 54	$ 197
Change in net unrealized gains (losses) on:
Investments with no other-than-temporary impairment, net of tax provision (benefit) of $25 and $(29)	163	(128)
Investments with other-than-temporary impairment, net of tax provision (benefit) of $0 and $(1)	5	(2)
Change in net unrealized gains (losses) on investments	168	(130)
Change in net unrealized gains (losses) on financial guaranty variable interest entities' liabilities with recourse resulting from a change in the instrument-specific credit risk, net of tax	0	(2)
Other, net of tax provision (benefit) of $0 and $1	0	6
Other comprehensive income (loss)	168	(126)
Comprehensive income (loss)	$ 222	$ 71