Income Taxes (Provision) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015		Sep. 30, 2016	Sep. 30, 2015
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income before income taxes	$ 60	$ 40	[1],[2]	$ 136	$ 61	[1],[2]
Income tax expense	$ 13	$ 8	[2]	$ 25	$ 8	[2]
Effective income tax rate	21.66667%	20.00%		18.38235%	13.10%
U.S. federal statutory rate (as a percent)				35.00%

[1] (a) Retrospectively adjusted as discussed in Note 1, Nature of Business.

[2] (a) Retrospectively adjusted as discussed in Note 1, Nature of Business.