Quarterly report pursuant to Section 13 or 15(d)

Roll-forward of Common Stock, Additional Paid-in Capital, and Retained Earnings Accounts (Detail)

v3.4.0.3
Roll-forward of Common Stock, Additional Paid-in Capital, and Retained Earnings Accounts (Detail) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Dec. 31, 2015
Stockholders Equity Note [Roll Forward]      
Common stock purchases (6.8)    
Balance at beginning of period $ 2,470    
Net income 1,131 $ 1,026  
Common stock purchases (680)    
Balance at end of period $ 2,457   $ 2,470
Class A common stock      
Stockholders Equity Note [Roll Forward]      
Balance at beginning of period 194.0 201.0 201.0
Common stock purchases (2.0) (1.0)  
Stock award plans 4.0 2.0  
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures $ 0 $ 0  
Common stock issuances 1.0 1.0  
Conversions of Class A to Class B common stock (3.0) (2.0)  
Stock Issued During Period, Value, Conversion of Convertible Securities $ 0 $ 0  
Balance at end of period 194.0 201.0 194.0
Balance at beginning of period $ 2 $ 2 $ 2
Common stock issuances 0 0  
Common stock purchases 0 0  
Balance at end of period $ 2 $ 2 $ 2
Class B common stock      
Stockholders Equity Note [Roll Forward]      
Balance at beginning of period 693.0 705.0 705.0
Common stock purchases (5.0) (6.0)  
Conversions of Class A to Class B common stock (3.0) (2.0)  
Stock Issued During Period, Value, Conversion of Convertible Securities $ 0 $ 0  
Balance at end of period 691.0 701.0 693.0
Balance at beginning of period $ 7 $ 7 $ 7
Common stock purchases 0 0  
Balance at end of period 7 7 7
Additional Paid-in Capital      
Stockholders Equity Note [Roll Forward]      
Balance at beginning of period 0 0 0
Stock award plans 137 124  
Common stock issuances 96 101  
Option premiums received (paid) 103 (99)  
Common stock purchases (336) (126)  
Balance at end of period 0 0 0
Retained Earnings      
Stockholders Equity Note [Roll Forward]      
Balance at beginning of period 6,001 5,726 5,726
Net income 1,131 1,026  
Dividends ($0.57 and $0.52 per share) (718) (683)  
Common stock purchases (319) (561)  
Balance at end of period $ 6,095 $ 5,508 $ 6,001
Common stock, cash paid for dividends, per share $ 0.78 $ 0.73