Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 161	$ 12	$ 347	$ 40
Other comprehensive income (loss), before tax:
Unrealized gains/losses on securities	(83)	70	(783)	354
Other-than-temporary impairments	1	0	8	2
Pension and other postretirement benefits liability	(1)	(1)	(2)	(2)
Other comprehensive income (loss), before tax	(83)	69	(777)	354
Income tax expense (benefit) related to items of other comprehensive income (loss)	(24)	24	(172)	123
Other comprehensive income (loss), after tax	(59)	45	(605)	231
Comprehensive income (loss)	$ 102	$ 57	$ (258)	$ 271