Asset Quality (Commercial Lending Asset Quality Indicators) (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	$ 5,167,000,000		$ 6,106,000,000		$ 6,398,000,000
Total Loans	200,872,000,000	[1],[2]	195,613,000,000	[1],[2]	192,856,000,000
Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	405,000,000				782,000,000
Total Loans	124,063,000,000		117,145,000,000		114,435,000,000
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	82,000,000		157,000,000
Total Loans	93,500,000,000		88,378,000,000
Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	93,418,000,000		88,221,000,000
Total Loans	93,500,000,000		88,378,000,000
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	323,000,000		516,000,000
Total Loans	22,942,000,000		21,191,000,000
Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	22,619,000,000		20,675,000,000
Total Loans	22,942,000,000		21,191,000,000
Equipment Lease Financing [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	7,621,000,000		7,576,000,000
Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	7,621,000,000		7,576,000,000
Total Loans	7,621,000,000		7,576,000,000
Purchased Impaired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	5,167,000,000		6,106,000,000
Purchased Impaired Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	405,000,000		673,000,000
Pass [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans			10,000,000
Total Loans	117,871,000,000		110,491,000,000
Pass [Member] | Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	88,809,000,000		83,903,000,000
Pass [Member] | Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	21,626,000,000		19,175,000,000
Pass [Member] | Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	7,436,000,000		7,403,000,000
Special Mention [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	4,000,000		31,000,000
Total Loans	2,390,000,000		2,303,000,000
Special Mention [Member] | Commercial [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	2,133,000,000		1,894,000,000
Special Mention [Member] | Commercial Real Estate [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	183,000,000		301,000,000
Special Mention [Member] | Equipment Lease Financing [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	70,000,000		77,000,000
Substandard [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	363,000,000		469,000,000
Total Loans	3,667,000,000		4,027,000,000
Substandard [Member] | Commercial [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	2,421,000,000		2,352,000,000
Substandard [Member] | Commercial Real Estate [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	770,000,000		1,113,000,000
Substandard [Member] | Equipment Lease Financing [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	113,000,000		93,000,000
Doubtful [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	38,000,000		163,000,000
Total Loans	135,000,000		324,000,000
Doubtful [Member] | Commercial [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	55,000,000		72,000,000
Doubtful [Member] | Commercial Real Estate [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	40,000,000		86,000,000
Doubtful [Member] | Equipment Lease Financing [Member] | Criticized Commercial Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	$ 2,000,000		$ 3,000,000

[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.