Asset Quality (Commercial Lending Asset Quality Indicators) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011		Sep. 30, 2011
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 181,864	[1],[2],[3],[4]	$ 159,014	[1],[2],[3],[4]	$ 154,543
Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	105,200		88,314
Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	79,314		65,554
Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	17,561		15,492
Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,923		6,416
Purchased Impaired Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,402		852
Pass [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	95,319		78,444
Pass [Member] | Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	74,228		60,649
Pass [Member] | Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	14,252		11,478
Pass [Member] | Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,750		6,210
Pass [Member] | Purchased Impaired Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	89		107
Special Mention [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	3,078		2,705
Special Mention [Member] | Commercial [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,130		1,831
Special Mention [Member] | Commercial Real Estate [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	842		791
Special Mention [Member] | Equipment Lease Financing [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	49		48
Special Mention [Member] | Purchased Impaired Loans [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	57		35
Substandard [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	6,005		6,335
Substandard [Member] | Commercial [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,749		2,817
Substandard [Member] | Commercial Real Estate [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,277		2,823
Substandard [Member] | Equipment Lease Financing [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	119		153
Substandard [Member] | Purchased Impaired Loans [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	860		542
Doubtful [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	798		830
Doubtful [Member] | Commercial [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	207		257
Doubtful [Member] | Commercial Real Estate [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	190		400
Doubtful [Member] | Equipment Lease Financing [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	5		5
Doubtful [Member] | Purchased Impaired Loans [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 396		$ 168

[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.