v3.8.0.1
Stock-Based Compensation Equity Classified Share Based Awards (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting period for graded and cliff vesting options - minimum     1 year    
Vesting period for graded and cliff vesting options - maximum     5 years    
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Minimum Range     5 years    
Share-based Compensation Arrangement by Share-based Payment Award, Award Expiration Maximum Range     10 years    
Allocated Share-based Compensation Expense $ 9 $ 7 $ 26 $ 22  
Restricted Stock [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 6,255,141 [1]   6,255,141 [1]   4,869,648
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options $ 28   $ 28    
Employee service share-based compensation, Nonvested awards, Restricted Stock 1 year 6 months        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value     $ 20 16  
Performance Shares [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 1,284,621   1,284,621   890,587
Allocated Share Based Compensation Expense Liability Classified Share-Based Awards $ 2 $ (1) $ 5 $ 1  
Director Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 63,075   63,075    
Common Stock, Capital Shares Reserved for Future Issuance 300,000   300,000    
Equity Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 6,192,066   6,192,066    
Common Stock, Capital Shares Reserved for Future Issuance 21,865,106   21,865,106    
Minimum [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term [2]     7 years 3 months 18 days    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate [3]     33.00%    
Maximum [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term [2]     10 years    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate [3]     40.00%    
[1] Includes 63,075 shares of restricted stock and restricted stock units outstanding under the Director Plans and 6,192,066 shares of restricted stock and restricted stock units outstanding under the Equity Plans
[2] Expected term calculated using historical exercise data.
[3] Volatility calculated using the implied volatility of our exchange traded stock options.