Loans Troubled Debt Restructurings (Details) $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($) contracts	Dec. 31, 2015 USD ($) contracts	Dec. 31, 2014 USD ($) contracts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts \| contracts	448	552	678
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default \| $	$ 37	$ 25	$ 36
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts \| contracts	22	34	78
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default \| $	$ 15	$ 1	$ 10
Residential Nonguaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts \| contracts	55	120	158
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default \| $	$ 11	$ 16	$ 19
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts \| contracts	137	138	101
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default \| $	$ 10	$ 6	$ 5
Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts \| contracts			6
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default \| $			$ 0
Consumer Other Direct [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts \| contracts	20	5	9
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default \| $	$ 0	$ 0	$ 0
Consumer Indirect [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts \| contracts	117	171	181
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default \| $	$ 1	$ 2	$ 1
Credit Card Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Restructured, Payment Default During Peiriod, Number of Contracts \| contracts	97	84	145
Financing Receivable, Restructured, Payment Default During Period, Amortized Cost at Default \| $	$ 0	$ 0	$ 1

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953682-111524

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Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

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