v2.4.0.6
Employee Benefit Plans - Summary of Restricted Stock Unit Activity (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Outstanding at December 31, 2008 7,802,863 6,719,552 5,927,698
Granted 2,746,045 2,890,010 2,910,095
Forfeited (299,531) (233,212) (207,932)
Issued (1,520,419) (1,573,487) (1,910,309)
Outstanding at December 31, 2009 8,728,958 7,802,863 6,719,552
Weighted-Average Grant-Date Fair Value, beginning of year $ 53.04 $ 57.08 $ 61.14
Not Vested at December 31, 2011 6,175,477    
Weighted-Average Grant-Date Fair Value, Granted $ 67.54 $ 46.38 $ 43.41
Weighted-Average Grant-Date Fair Value, Forfeited $ 56.43 $ 53.11 $ 51.84
Weighted-Average Grant-Date Fair Value, ending of year $ 55.41 $ 53.04 $ 57.08
Weighted-Average Grant-Date Fair Value Not Vested, ending of year $ 55.93    
Total Fair Value, issued $ 109 $ 79 $ 88
Performance Share Program [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Outstanding at December 31, 2008 3,434,586 3,404,878 3,176,178
Granted 615,780 317,072 659,812
Forfeited (23,240) (53,243) (23,670)
Issued (509,365) (234,121) (407,442)
Outstanding at December 31, 2009 3,517,761 3,434,586 3,404,878
Weighted-Average Grant-Date Fair Value, beginning of year $ 63.43 $ 64.63 $ 68.13
Not Vested at December 31, 2011 1,063,982    
Weighted-Average Grant-Date Fair Value, Granted $ 70.57 $ 48.39 $ 45.47
Weighted-Average Grant-Date Fair Value, Forfeited $ 63.18 $ 62.66 $ 65.00
Weighted-Average Grant-Date Fair Value, ending of year $ 64.35 $ 63.43 $ 64.63
Weighted-Average Grant-Date Fair Value Not Vested, ending of year $ 64.16    
Total Fair Value, issued $ 37 $ 12 $ 19