v3.20.4
Share-Based Payments (Details)
shares in Millions, $ in Millions
12 Months Ended
Dec. 31, 2020
USD ($)
shares
Long-Term Incentive Plan | Class A Common Stock  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Shares reserve for future issuance | shares 116
Stock Option  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period 10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period 4 years
Unrecognized compensation cost $ 37
Period over which unrecognized cost will be recognized, in years 2 years 1 month 6 days
Stock Option | Vesting period for retirement or disability  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period 7 months
Restricted Stock Units (RSUs)  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period 3 years
Unrecognized compensation cost $ 233
Period over which unrecognized cost will be recognized, in years 2 years 4 months 24 days
Performance Shares  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period 3 years
Performance Shares | Minimum vesting from date of retirement eligibility  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period 7 months
Performance-Based Restricted Stock  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Unrecognized compensation cost $ 38
Period over which unrecognized cost will be recognized, in years 1 year 4 months 24 days