Loans - Summary of Consumer Loans excluding Credit Card (Details 5) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	$ 712,898	$ 718,997	$ 675,437
Consumer Loan Excluding Credit Card
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	304,770	308,427
Residential real estate, excluding PCI [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	160,788	163,660
Home Equity - Senior Lien [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	21,202	21,765
Home Equity - Junior Lien [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	54,005	56,035
Prime Mortgages, including option ARMs [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	76,292	76,196
Subprime Mortgage [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	9,289	9,664
Total other consumer [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	79,921	79,221
Auto [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	48,245	47,426
Consumer business banking
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	17,822	17,652
Student And Other Loans [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	13,854	14,143
PCI Home Equity [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	22,305	22,697
PCI Prime Mortgage [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	14,781	15,180
PCI Subprime Mortgage [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	4,870	4,976
PCI Option ARMs [Member]
Consumer loans by class, excluding the credit card loan portfolio segment
Retained loans	$ 22,105	$ 22,693