Geographic Regions (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
Segment Revenues and Pretax Income (Loss) by Geographic Location [Line Items]
Revenues	$ 179	$ 180	$ 179	$ 180	$ 180	$ 187	$ 193	$ 195	$ 718	$ 755	$ 929
Pretax income	$ 20	$ 70	$ 65	$ 57	$ 68	$ 45	$ 69	$ 70	212	252	318
United States [Member]
Segment Revenues and Pretax Income (Loss) by Geographic Location [Line Items]
Revenues									440	442	524
Pretax income									16	111	165
Outside the United States [Member]
Segment Revenues and Pretax Income (Loss) by Geographic Location [Line Items]
Revenues									278	313	405
Pretax income									$ 196	$ 141	$ 153