Income Taxes (Provision) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended			12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014		Sep. 30, 2015	Sep. 30, 2014		Dec. 31, 2014
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income before income taxes	$ 42	$ 49	[1]	$ 67	$ 122	[1]
Income tax expense	$ 8	$ 10		$ 8	$ 15
Effective income tax rate	19.04762%	20.40%		11.9403%	12.30%
U.S. federal statutory rate (as a percent)				35.00%
Adjustments to Additional Paid in Capital, Other				$ 29			$ 65

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