Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation Plans - Restricted Stock Units (Details)

v3.8.0.1
Stock-based Compensation Plans - Restricted Stock Units (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Weighted-average Grant Date Fair Value      
Cash used to settle awards $ 1,900 $ 1,700 $ 3,000
Stock-settled Restricted Stock and Restricted Stock Units      
Shares/Units      
Outstanding at beginning of period (in shares) 156,492,946    
Granted (in shares) 81,555,447    
Vested (in shares) (52,187,746)    
Canceled (in shares) (6,587,404)    
Outstanding at end of period (in shares) 179,273,243 156,492,946  
Weighted-average Grant Date Fair Value      
Outstanding at beginning of period (in dollars per share) $ 11.99    
Granted (in dollars per share) 24.58    
Vested (in dollars per share) 12.01    
Canceled (in dollars per share) 16.93    
Outstanding at end of period (in dollars per share) $ 17.53 $ 11.99  
Cash-settled Restricted Stock Units | Key Employee Equity Plan      
Shares/Units      
Outstanding at beginning of period (in shares) 121,235,489    
Granted (in shares) 3,105,988    
Vested (in shares) (79,525,864)    
Canceled (in shares) (2,605,987)    
Outstanding at end of period (in shares) 42,209,626 121,235,489  
Restricted Stock and Restricted Stock Units      
Weighted-average Grant Date Fair Value      
Total unrecognized compensation cost $ 1,100    
Expected period of total unrecognized compensation cost 4 years    
Total unrecognized compensation cost, period for recognition 1 year 8 months 12 days    
Fair value of vested in period $ 1,300 $ 358 $ 145