Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation Plans - Additional Information (Details)

v3.8.0.1
Stock-based Compensation Plans - Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended 108 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2017
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock-based compensation cost $ 2,200 $ 2,200 $ 2,100    
Tax benefit from compensation expense $ 829 $ 835 $ 792    
Options granted (in shares)       0  
Restricted Stock Units (RSUs)          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of vesting installments 3 years        
Restricted Stock Units (RSUs) | Year 1          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage 33.33%        
Restricted Stock Units (RSUs) | Year 2          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage 33.33%        
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          
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) 85,000,000 163,000,000