Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation Plans - Additional Information (Details)

v3.10.0.1
Stock-based Compensation Plans - Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock-based compensation cost $ 1,800 $ 2,200 $ 2,200
Tax benefit from compensation expense 433 829 835
Cash used to settle awards 1,300 1,900 1,700
Restricted Stock and Restricted Stock Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total unrecognized compensation cost $ 1,100    
Expected period of total unrecognized compensation cost 4 years    
Total unrecognized compensation cost, period for recognition 1 year 10 months 24 days    
Fair value of vested in period $ 2,300 $ 1,300 $ 358
Key Employee Equity Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares authorized (in shares) 450,000,000    
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) 71,000,000 85,000,000  
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) 63,000,000 85,000,000  
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) 8,000,000    
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%