Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Prepaid Taxes	$ 51	$ 248
Change in valuation allowance	2	1
Unrecognized tax benefits that would impact effective tax rate	17
Interest expense (income) related to unrecognized tax benefits	(3)	1	$ 1
Interest accrued related to unrecognized tax benefits	$ 2	$ 6