Loans - by Portfolio Segment and Class (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Loans by Portfolio Segment and Class [Line Items]
Total loans	$ 728,886,000,000	$ 733,796,000,000
Loans retained	722,529,000,000	726,835,000,000	712,898,000,000
Loans held-for-sale	4,196,000,000	4,406,000,000
Loans at fair value	2,161,000,000	2,555,000,000
Loans unearned income, unamortized discounts and premiums, and net deferred loan costs	2,400,000,000	2,500,000,000
Consumer, excluding credit card
Loans by Portfolio Segment and Class [Line Items]
Total loans	290,082,000,000	292,620,000,000
Loans retained	290,082,000,000	292,620,000,000	304,770,000,000
Loans held-for-sale	0	0
Loans at fair value	0	0
Consumer, excluding credit card | Consumer Loan Excluding Credit Card
Loans by Portfolio Segment and Class [Line Items]
Loans retained	290,082,000,000	292,620,000,000
Consumer, excluding credit card | Residential Real Estate, Excluding Purchased Credit-Impaired [Member]
Loans by Portfolio Segment and Class [Line Items]
Loans retained	150,427,000,000	151,896,000,000
Consumer, excluding credit card | Home Equity - Senior Lien
Loans by Portfolio Segment and Class [Line Items]
Loans retained	18,743,000,000	19,385,000,000
Consumer, excluding credit card | Home Equity - Junior Lien
Loans by Portfolio Segment and Class [Line Items]
Loans retained	46,055,000,000	48,000,000,000
Consumer, excluding credit card | Prime Mortgages, Including Option ARMs
Loans by Portfolio Segment and Class [Line Items]
Loans retained	77,626,000,000	76,256,000,000
Consumer, excluding credit card | Subprime Mortgages
Loans by Portfolio Segment and Class [Line Items]
Loans retained	8,003,000,000	8,255,000,000
Consumer, excluding credit card | Purchased Credit-Impaired [Member]
Loans by Portfolio Segment and Class [Line Items]
Loans retained	58,437,000,000	59,737,000,000
Consumer, excluding credit card | PCI Home Equity [Member]
Loans by Portfolio Segment and Class [Line Items]
Loans retained	20,525,000,000	20,971,000,000
Consumer, excluding credit card | PCI Prime Mortgage [Member]
Loans by Portfolio Segment and Class [Line Items]
Loans retained	13,366,000,000	13,674,000,000
Consumer, excluding credit card | PCI Subprime Mortgage [Member]
Loans by Portfolio Segment and Class [Line Items]
Loans retained	4,561,000,000	4,626,000,000
Consumer, excluding credit card | PCI Option ARMs [Member]
Loans by Portfolio Segment and Class [Line Items]
Loans retained	19,985,000,000	20,466,000,000
Consumer, excluding credit card | Other Consumer [Member]
Loans by Portfolio Segment and Class [Line Items]
Loans retained	81,218,000,000	80,987,000,000
Consumer, excluding credit card | Auto Loans
Loans by Portfolio Segment and Class [Line Items]
Loans retained	50,552,000,000	49,913,000,000
Consumer, excluding credit card | Business Banking Loans
Loans by Portfolio Segment and Class [Line Items]
Loans retained	18,739,000,000	18,883,000,000
Consumer, excluding credit card | Student and Other Loans
Loans by Portfolio Segment and Class [Line Items]
Loans retained	11,927,000,000	12,191,000,000
Credit card
Loans by Portfolio Segment and Class [Line Items]
Total loans	121,865,000,000	127,993,000,000
Loans retained	121,865,000,000	127,993,000,000	124,475,000,000
Loans held-for-sale	0	0
Loans at fair value	0	0
Wholesale
Loans by Portfolio Segment and Class [Line Items]
Total loans	316,939,000,000	313,183,000,000
Loans retained	310,582,000,000	306,222,000,000	283,653,000,000
Loans held-for-sale	4,196,000,000	4,406,000,000
Loans at fair value	$ 2,161,000,000	$ 2,555,000,000