Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation - Narrative (Details)

v3.19.3.a.u2
Share-Based Compensation - Narrative (Details) - USD ($)
$ in Millions
1 Months Ended 12 Months Ended
Jan. 31, 2017
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Restricted Stock Share Awards [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting Period - service years, option 1   1 year    
Vesting Period - service years, option 2   2 years    
Vesting Period - service years, option 3   3 years    
Vesting Period - service years, option 4   4 years    
Vested in Period, Fair Value   $ 3 $ 53 $ 78
Number of Units Granted   0.0    
Restricted Stock Units (RSUs) [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting Period - service years, option 1   3 years    
Performance Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Award Vesting Period, Cliff Vesting   3 years    
Performance Units [Member] | Minimum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Percentage of Target Amount Earned Upon Vesting If Threshold Performance is Met   25.00%    
Performance Units [Member] | Maximum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Percentage of Target Amount Earned Upon Vesting If Threshold Performance is Met   300.00%    
Phantom Unit Awards [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting Period - service years, option 1   2 years    
Vesting Period - service years, option 2   3 years    
Vesting Period - service years, option 3   4 years    
Vested in Period, Fair Value   $ 11 $ 91 $ 86
Number of Units Granted   0 0 0
2003 Stock Incentive Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of Shares Authorized   21,000,000.0    
2011 Incentive Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of Shares Authorized   35,000,000.0    
Number of Additional Shares Authorized 7,800,000      
Inducement Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of Shares Authorized   1,000,000.0    
Number of Shares Granted Plan-to-Date   200,000    
Share-based Payment Award, Number of Shares Available for Grant   0