v2.4.0.6
Income Taxes, Effective Income Tax Expense and Rate (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]      
Statutory federal income tax expense $ 9,800 $ 8,160 $ 6,545
Statutory federal income tax expense, rate 35.00% 35.00% 35.00%
Change in tax rate resulting from: [Abstract]      
State and local taxes on income, net of federal income tax benefit 856 730 586
State and local taxes on income, net of federal income tax benefit, rate 3.10% 3.10% 3.10%
Tax-exempt interest (414) (334) (283)
Tax-exempt interest, rate (1.50%) (1.40%) (1.50%)
Excludable dividends (132) (247) (258)
Excludable dividends, rate (0.50%) (1.10%) (1.30%)
Tax credits (815) (735) (577)
Tax credits, rate (2.90%) (3.20%) (3.10%)
Life insurance (524) (222) (223)
Life insurance, rate (1.90%) (1.00%) (1.20%)
Leveraged lease tax expense 347 272 461
Leveraged lease tax expense, rate 1.20% 1.20% 2.50%
Other (15) (179) 87
Other, rate 0.00% (0.70%) 0.40%
Effective income tax expense $ 9,103 $ 7,445 $ 6,338
Effective income tax rate 32.50% 31.90% 33.90%