Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation Plans - Additional Information (Details)

v3.20.4
Stock-based Compensation Plans - Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock-based compensation cost $ 2,100 $ 2,100 $ 1,800
Tax benefit from compensation expense 505 511 433
Cash used to settle awards 81 84 1,300
Restricted Stock and Restricted Stock Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total unrecognized compensation cost $ 2,000    
Expected period of total unrecognized compensation cost 4 years    
Total unrecognized compensation cost, period for recognition 2 years 2 months 12 days    
Fair value of vested in period $ 2,300 $ 2,600 $ 2,300
Cash-settled Restricted Stock Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Cash-settled RSUs outstanding (in shares) 2,000,000    
Key Employee Equity Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares authorized (in shares) 600,000,000    
Key Employee Equity Plan | Restricted Stock Units (RSUs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock units granted in period (in shares) 86,000,000 94,000,000  
Key Employee Equity Plan, Vesting In One-Third Increments | Restricted Stock Units (RSUs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock units granted in period (in shares) 61,000,000 71,000,000  
Number of vesting installments 3 years    
Key Employee Equity Plan, Vesting In One-Third Increments | Restricted Stock Units (RSUs) | Year 1      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting percentage 33.33%    
Key Employee Equity Plan, Vesting In One-Third Increments | Restricted Stock Units (RSUs) | Year 2      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting percentage 33.33%    
Key Employee Equity Plan, Vesting In One-Third Increments | Restricted Stock Units (RSUs) | Year 3      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting percentage 33.33%    
Key Employee Equity Plan, Vesting In One-Fourth Increments | Restricted Stock Units (RSUs)      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock units granted in period (in shares) 25,000,000 23,000,000  
Number of vesting installments 4 years    
Key Employee Equity Plan, Vesting In One-Fourth Increments | Restricted Stock Units (RSUs) | Year 1      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting percentage 25.00%    
Key Employee Equity Plan, Vesting In One-Fourth Increments | Restricted Stock Units (RSUs) | Year 2      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting percentage 25.00%    
Key Employee Equity Plan, Vesting In One-Fourth Increments | Restricted Stock Units (RSUs) | Year 3      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting percentage 25.00%    
Key Employee Equity Plan, Vesting In One-Fourth Increments | Restricted Stock Units (RSUs) | Year 4      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting percentage 25.00%