Loans Troubled Debt Restructurings (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 contracts	Mar. 31, 2013 contracts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	169	246
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	$ 7	$ 13
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	25	23
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	1	0
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	0	1
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	0	3
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	0	1
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	0	0
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	49	76
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	4	4
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	23	49
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	1	3
Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	4	6
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	0	1
Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	5	7
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	0	0
Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	43	39
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	1	1
Consumer Credit Card Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	20	44
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	$ 0	$ 1