Asset Quality (Home Equity and Residential Real Estate Balances) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Purchased Impaired Loans - Outstanding Balance	$ 5,007,000,000		$ 6,485,000,000
Total loans	204,817,000,000	[1],[2]	195,613,000,000	[1],[2]	185,856,000,000
Total home equity and residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	43,348,000,000		44,376,000,000
Purchased Impaired Loans - Outstanding Balance	4,541,000,000		5,548,000,000
Government insured or guaranteed residential real estate mortgages	1,188,000,000		1,704,000,000
Purchase accounting adjustments - purchased impaired loans	7,000,000		(116,000,000)
Total loans	$ 49,084,000,000		$ 51,512,000,000

[1] Amounts represent the assets or liabilities of consolidated variable interest entities (VIEs).

[2] Amounts represent items for which we have elected the fair value option.