Loans and Allowance for Credit Losses, Nonaccrual (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	$ 19,526	$ 20,486
Total Commercial [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	5,242	5,824
Commercial and Industrial Loans [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	1,193	1,422
Commercial Real Estate Mortgage [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	3,098	3,322
Commercial Real Estate Construction [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	870	1,003
Lease Financing [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	25	27
Foreign Loans [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	56	50
Total Consumer [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	14,284	14,662
Real estate 1-4 family first mortgage [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	11,320	11,455
Real estate 1-4 family junior lien mortgage [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	2,712	2,922
Automobile [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	220	245
Other revolving credit and installment [Member]
Nonaccrual Loans [Abstract]
Financing Receivable, Recorded Investment, nonaccrual status	$ 32	$ 40