Income Taxes (Income Tax Expense (Benefit)) (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 [Line Items]
Income tax (expense) benefit	$ 14	$ (5)	$ (21)	$ (4)
Effective Income Tax Rate, Continuing Operations	33.00%	21.00%	(10.00%)	31.00%
Income Tax Uncertainties [Abstract]
Unrecognized Tax Benefits	$ 58		$ 58
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	18		18
Unrecognized Tax Benefit Related to Deferred Tax Asset	40		40
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	13		13
Minimum [Member]
Income Tax Contingency [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	0		0
Maximum [Member]
Income Tax Contingency [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 18		$ 18