Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 110	$ 161	$ 304	$ 347
Other comprehensive income (loss), before tax:
Unrealized gains/losses on securities	286	(83)	1,417	(783)
Other-than-temporary impairments	0	1	1	8
Pension and other postretirement benefits liability	0	(1)	(1)	(2)
Other comprehensive income (loss), before tax	286	(83)	1,417	(777)
Income tax expense (benefit) related to items of other comprehensive income (loss)	60	(24)	296	(172)
Other comprehensive income (loss), after tax	226	(59)	1,121	(605)
Comprehensive income (loss)	$ 336	$ 102	$ 1,425	$ (258)