Quarterly report pursuant to Section 13 or 15(d)

Activity in Deferred Compensation Program (Detail)

v2.4.0.6
Activity in Deferred Compensation Program (Detail) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Dec. 31, 2012
Stockholders Equity Note [Roll Forward]      
Balance at beginning of period     (1)
Balance at end of period (1)   (1)
Balance at beginning of period     $ 4,653
Balance at end of period 4,028   4,653
Treasury Stock [Member]
      
Stockholders Equity Note [Roll Forward]      
Balance at beginning of period   (2) (1)
Reinvested dividends 0 0  
Benefit payments 0 0  
Balance at end of period (1) (2) (1)
Balance at beginning of period   (88) (78)
Reinvested dividends (1) (1)  
Benefit payments 13 13  
Balance at end of period (66) (76) (78)
Deferred Compensation Obligations
      
Stockholders Equity Note [Roll Forward]      
Balance at beginning of period   88 78
Reinvested dividends 1 1  
Benefit payments (13) (13)  
Balance at end of period $ 66 $ 76 $ 78