Quarterly Results (Unaudited) Level 4 (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 571	$ 702	$ 622	$ 487	$ 499	$ 630	$ 702	$ 668	$ 2,382	$ 2,499	$ 3,362
Total benefits, losses and expenses	464	610	474	478	525	500	461	483	2,026	1,969	2,501
Net income	57	79	118	28	7	118	230	145	282	500	677
Less: Net income (loss) attributable to the noncontrolling interest	0	0	0	0	(1)	1	0	0	0	0	1
Net Income (Loss) Attributable to Parent	$ 57	$ 79	$ 118	$ 28	$ 8	$ 117	$ 230	$ 145	$ 282	$ 500	$ 676