Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation - Narrative (Details)

v3.20.4
Share-Based Compensation - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Restricted Stock Units (RSUs) [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share Based Compensation Arrangement By Share Based Payment Award, Award Vesting Period, Vests Ratably Over Service Period 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 0.00%    
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%    
Common Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Units Granted 200,000    
Restricted Stock Share Awards [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Units Granted 100,000    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period 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    
Fair value of units vested $ 3 $ 3 $ 53
Phantom Unit Awards [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Units Granted 0    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period 2 years    
Vesting Period - service years, option 2 3 years    
Vesting Period - service years, option 3 4 years    
Fair value of units vested $ 4 $ 11 $ 91
2011 Incentive Plan [Member] | Common Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized 35,000,000.0    
2020 Incentive Plan [Member] | Common Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized 8,000,000.0