v2.4.0.6
Income Taxes, Effective Income Tax Expense and Rate (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]      
Statutory federal income tax expense $ 8,160 $ 6,545 $ 6,162
Statutory federal income tax expense rate 35.00% 35.00% 35.00%
Change in tax rate resulting from:      
State and local taxes on income, net of federal income tax benefit 730 586 468
State and local taxes on income, net of federal income tax benefit, rate 3.10% 3.10% 2.70%
Tax-exempt interest (334) (283) (260)
Tax-exempt interest, rate (1.40%) (1.50%) (1.50%)
Tax credits (735) (577) (533)
Tax credits, rate (3.20%) (3.10%) (3.00%)
Life insurance (222) (223) (257)
Life insurance, rate (1.00%) (1.20%) (1.50%)
Leveraged lease tax expense 272 461 400
Leveraged lease tax expense, rate 1.20% 2.50% 2.30%
Other (179) 87 (396)
Other, rate (0.70%) 0.40% (2.30%)
Effective income tax expense 7,445 6,338 5,331
Effective income tax rate 31.90% 33.90% 30.30%
Excludable dividends [Member]
     
Change in tax rate resulting from:      
Dividends $ (247) $ (258) $ (253)
Dividends, rate (1.10%) (1.30%) (1.40%)