Loans and ACL (Summary of the pre-default balance for modifications that experienced a payment default) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commercial and Industrial, Excluding Covered [Member]
Financing Receivable, Modifications [Line Items]
Modifications that defaulted during the period that had been classified as a TDR during the previous 12 months	$ 5	$ 8	$ 39
CRE - Other, Excluding Covered [Member]
Financing Receivable, Modifications [Line Items]
Modifications that defaulted during the period that had been classified as a TDR during the previous 12 months	11	6	92
CRE - Residential ADC, Excluding Covered [Member]
Financing Receivable, Modifications [Line Items]
Modifications that defaulted during the period that had been classified as a TDR during the previous 12 months	4	14	80
Direct Retail Lending, Excluding Covered [Member]
Financing Receivable, Modifications [Line Items]
Modifications that defaulted during the period that had been classified as a TDR during the previous 12 months	4	8	16
Retail Revolving Credit, Excluding Covered [Member]
Financing Receivable, Modifications [Line Items]
Modifications that defaulted during the period that had been classified as a TDR during the previous 12 months	10	12	15
Retail Residential Mortgage, Excluding Covered [Member]
Financing Receivable, Modifications [Line Items]
Modifications that defaulted during the period that had been classified as a TDR during the previous 12 months	17	36	31
Retail Sales Finance, Excluding Covered [Member]
Financing Receivable, Modifications [Line Items]
Modifications that defaulted during the period that had been classified as a TDR during the previous 12 months	1	0	2
Retail Other Lending Subsidiaries, Excluding Covered [Member]
Financing Receivable, Modifications [Line Items]
Modifications that defaulted during the period that had been classified as a TDR during the previous 12 months	$ 26	$ 12	$ 5