v3.8.0.1
Income Taxes (Income Tax Expense (Benefit)) (Details)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Dec. 31, 2016
USD ($)
Income Tax Contingency [Line Items]          
Income tax (expense) benefit $ 2 $ 4 $ 0 $ (17)  
Effective Income Tax Rate, Continuing Operations (1.00%) (1.00%) 0.00% 20.00%  
Income Tax Uncertainties [Abstract]          
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions     $ 17    
Number of States for NOL Carryforwards         21
Unrecognized Tax Benefits $ 48   48    
Unrecognized Tax Benefits that Would Impact Effective Tax Rate 10   10    
Unrecognized Tax Benefit Related to Deferred Tax Asset 38   38    
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued 4   4    
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 $ 7   $ 7    
Expiration date 2024 through 2033 [Member]          
Income Tax Uncertainties [Abstract]          
Deferred Tax Assets, Operating Loss Carryforwards, Domestic         $ 6,700
Expiration date 2017 through 2036 [Member]          
Income Tax Uncertainties [Abstract]          
Deferred Tax Assets, Operating Loss Carryforwards, State and Local         3,700
Expiration date 2025 through 2033 [Member]          
Income Tax Uncertainties [Abstract]          
Deferred Tax Assets, Operating Loss Carryforwards, Foreign         647
Foreign Tax Authority [Member]          
Income Tax Uncertainties [Abstract]          
Deferred Tax Assets, Net of Valuation Allowance         161
Deferred Tax Assets, Valuation Allowance         $ 101