Income Taxes (Income Tax Contingency and Taxes Paid Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Tax Contingency [Abstract]
Unrecognized benefit that would affect the effective tax rate	$ 5		$ 5
Amount of interest and penalties included in liabilities for uncertain tax positions	$ 3		$ 3
Effective Income Tax Rate, Continuing Operations	8.90%	34.60%	7.60%	34.00%
Cash Paid for Income Taxes, Net of Refunds Received [Abstract]
Cash paid for income taxes (refunds received), net	$ 4	$ 8	$ 4	$ 9