Quarterly report pursuant to Section 13 or 15(d)

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

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Roll-forward of Common Stock, Additional Paid-in Capital, and Retained Earnings Accounts (Detail) (USD $)
In Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2011
Jun. 30, 2010
Jun. 30, 2011
Jun. 30, 2010
Stockholders Equity Note [Line Items]        
Common stock purchases     (14.4) (6.9)
Balance at beginning of period     $ 7,979  
Net income 1,063 845 1,948 1,378
Common stock purchases     (1,055) (427)
Balance at end of period 8,254   8,254  
Class A common stock
        
Stockholders Equity Note [Line Items]        
Balance at beginning of period     258 285
Common stock purchases     (4.0) (3.0)
Stock award plans     2 2
Common stock issuances     2 2
Conversions of Class A to Class B common stock     (11) (17)
Balance at end of period 247 269 247 269
Balance at beginning of period     3 3
Stock award plans        
Conversions of Class A to Class B common stock        
Balance at end of period 3 3 3 3
Class B common stock
        
Stockholders Equity Note [Line Items]        
Balance at beginning of period     735 711
Common stock purchases     (10.0) (4.0)
Conversions of Class A to Class B common stock     11 17
Balance at end of period 736 724 736 724
Balance at beginning of period     7 7
Conversions of Class A to Class B common stock        
Balance at end of period 7 7 7 7
Additional Paid-In Capital
        
Stockholders Equity Note [Line Items]        
Balance at beginning of period       2
Stock award plans     236 206
Common stock purchases     (209) (318)
Common stock issuances     126 115
Option premiums paid     (150)  
Balance at end of period 3 5 3 5
Retained Earnings
        
Stockholders Equity Note [Line Items]        
Balance at beginning of period     14,164 12,745
Net income     1,948 1,378
Dividends ($1.04 and $0.94 per share)     (1,048) (947)
Common stock purchases     (846) (109)
Balance at end of period $ 14,218 $ 13,067 $ 14,218 $ 13,067