Asset Quality (Commercial Lending Asset Quality Indicators) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012		Jun. 30, 2012
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 189,775	[1],[2]	$ 185,856	[1],[2]	$ 180,425
Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	113,270		108,942
Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	86,699		82,732
Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	18,254		17,714
Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	7,349		7,247
Purchased Impaired Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	968		1,249
Pass [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	106,163		100,057
Pass [Member] | Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	82,619		78,048
Pass [Member] | Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	16,344		14,898
Pass [Member] | Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	7,169		7,062
Pass [Member] | Purchased Impaired Loans [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	31		49
Special Mention [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,147		2,871
Special Mention [Member] | Commercial [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,607		1,939
Special Mention [Member] | Commercial Real Estate [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	399		804
Special Mention [Member] | Equipment Lease Financing [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	99		68
Special Mention [Member] | Purchased Impaired Loans [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	42		60
Substandard [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	4,556		5,366
Substandard [Member] | Commercial [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2,363		2,600
Substandard [Member] | Commercial Real Estate [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	1,382		1,802
Substandard [Member] | Equipment Lease Financing [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	79		112
Substandard [Member] | Purchased Impaired Loans [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	732		852
Doubtful [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	404		648
Doubtful [Member] | Commercial [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	110		145
Doubtful [Member] | Commercial Real Estate [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	129		210
Doubtful [Member] | Equipment Lease Financing [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	2		5
Doubtful [Member] | Purchased Impaired Loans [Member] | Total commercial lending [Member] | Criticized Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans	$ 163		$ 288

[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.