Loans and Allowance for Credit Losses, Commitments to Lend (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	$ 483,091	$ 453,431
Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	294,370	269,681
Commercial and Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	257,488	238,962
Commercial Real Estate Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	5,436	5,910
Commercial Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	14,213	12,593
Foreign Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	17,233	12,216
Total Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	188,721	183,750
Real estate 1-4 family first mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	32,048	32,908
Real estate 1-4 family junior lien mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	45,829	47,668
Credit Card [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	86,915	78,961
Other revolving credit and installment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unfunded credit commitments	$ 23,929	$ 24,213