v2.4.0.6
Common Stock and Stock Plans, ESOP (Details) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Employee Stock Ownership Plan [Abstract]      
Allocated shares (common) 136,821,035 131,046,406 118,901,327
Preferred stock [Member]
     
Employee Stock Ownership Plan [Abstract]      
Unreleased shares 910,934 858,759 618,382
Fair value of unreleased ESOP $ 911 $ 859 $ 618
Dividends paid to ESOP 115 95 76
Common stock [Member]
     
Employee Stock Ownership Plan [Abstract]      
Dividends paid to ESOP $ 117 $ 60 $ 23