Loans Troubled Debt Restructurings (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012 contracts		Sep. 30, 2011 contracts		Sep. 30, 2012 contracts		Sep. 30, 2011 contracts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	159	[1]	323	[2]	486	[1]	993	[2]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	$ 6	[1]	$ 54	[2]	$ 43	[1]	$ 173	[2]
Commercial Construction [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	2	[1]	1	[2]	9	[1]	15	[2]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	0	[1]	0	[2]	6	[1]	24	[2]
Residential Nonguaranteed [Member] | Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	31	[1]	60	[2]	87	[1]	394	[2]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	2	[1]	19	[2]	16	[1]	95	[2]
Home Equity | Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	32	[1]	60	[2]	113	[1]	171	[2]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	2	[1]	6	[2]	9	[1]	17	[2]
Residential Construction | Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	6	[1]	6	[2]	23	[1]	29	[2]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	1	[1]	1	[2]	3	[1]	6	[2]
Consumer Other Direct | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	2	[1]	2	[2]	4	[1]	9	[2]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	0	[1]	0	[2]	0	[1]	0	[2]
Consumer Indirect | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	15	[1]			15	[1]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	0	[1]			0	[1]
Commercial and Industrial | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	38	[1]	23	[2]	63	[1]	43	[2]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	1	[1]	6	[2]	4	[1]	8	[2]
Commercial Real Estate | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	0	[1]	5	[2]	4	[1]	11	[2]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	0	[1]	21	[2]	4	[1]	21	[2]
Consumer Credit Card | Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts	33	[1]	166	[2]	168	[1]	321	[2]
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default	$ 0	[1]	$ 1	[2]	$ 1	[1]	$ 2	[2]

[1] For the three and nine months ended September 30, 2012, this represents defaults on loans that were first modified between the periods July 1, 2011 and September 30, 2012, and January 1, 2011 and September 30, 2012, respectively, including loans modified under the terms of a TDR that were charged-off during the periods.

[2] For the three and nine months ended September 30, 2011, this represents defaults on loans that were first modified between the periods July 1, 2010 and September 30, 2011, and January 1, 2010 and September 30, 2011, respectively, including loans modified under the terms of a TDR that were charged-off during the periods.