Loans and Commitments to Extend Credit (Loans Outstanding) (Details) (USD $)	Sep. 30, 2012		Dec. 31, 2011		Sep. 30, 2011
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 181,864,000,000	[1],[2],[3],[4]	$ 159,014,000,000	[1],[2],[3],[4]	$ 154,543,000,000
Unearned income, net deferred loan fees, unamortized discounts and premiums, and purchase discounts and premiums	2,900,000,000		2,300,000,000
Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	105,200,000,000		88,314,000,000
Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	76,664,000,000		70,700,000,000
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	79,668,000,000		65,694,000,000
Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	79,668,000,000		65,694,000,000
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	18,609,000,000		16,204,000,000
Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	18,609,000,000		16,204,000,000
Equipment Lease Financing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,923,000,000		6,416,000,000
Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,923,000,000		6,416,000,000
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	35,878,000,000		33,089,000,000
Home Equity [Member] | Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	35,878,000,000		33,089,000,000
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	15,383,000,000		14,469,000,000
Residential Real Estate [Member] | Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	15,383,000,000		14,469,000,000
Credit Card [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	4,135,000,000		3,976,000,000
Credit Card [Member] | Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	4,135,000,000		3,976,000,000
Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	21,268,000,000		19,166,000,000
Other Consumer [Member] | Total consumer lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 21,268,000,000		$ 19,166,000,000

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

[2] Amounts represent items for which the Corporation has elected the fair value option.

[3] Net of unearned income, net deferred loan fees, unamortized discounts and premiums, and purchase discounts and premiums totaling $2.9 billion and $2.3 billion atSeptember 30, 2012 and December 31, 2011, respectively.

[4] Future accretable yield related to purchased impaired loans is not included in loans outstanding.