Asset Quality (Commercial Lending Asset Quality Indicators) (Details) - USD ($)	Jun. 30, 2016		Dec. 31, 2015		Jun. 30, 2015
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	$ 3,236,000,000				$ 4,465,000,000
Total Loans	209,056,000,000	[1]	$ 206,696,000,000	[1]	205,153,000,000
Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	138,000,000		169,000,000		235,000,000
Total Loans	137,022,000,000		133,544,000,000		$ 130,722,000,000
Total commercial lending [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	100,536,000,000		98,572,000,000
Total Loans	100,562,000,000		98,608,000,000
Total commercial lending [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	28,728,000,000		27,335,000,000
Total Loans	28,840,000,000		27,468,000,000
Total commercial lending [Member] | Equipment Lease Financing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	7,620,000,000		7,468,000,000
Total Loans	7,620,000,000		7,468,000,000
Pass [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	35,000,000
Total Loans	130,584,000,000		127,323,000,000
Pass [Member] | Total commercial lending [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	94,962,000,000		93,364,000,000
Pass [Member] | Total commercial lending [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	28,251,000,000		26,729,000,000
Pass [Member] | Total commercial lending [Member] | Equipment Lease Financing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	7,336,000,000		7,230,000,000
Special Mention [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	1,000,000		6,000,000
Total Loans	2,299,000,000		2,242,000,000
Special Mention [Member] | Total commercial lending [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	2,174,000,000		2,029,000,000
Special Mention [Member] | Total commercial lending [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	68,000,000		120,000,000
Special Mention [Member] | Total commercial lending [Member] | Equipment Lease Financing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	56,000,000		87,000,000
Substandard [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	91,000,000		157,000,000
Total Loans	3,945,000,000		3,877,000,000
Substandard [Member] | Total commercial lending [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	3,237,000,000		3,089,000,000
Substandard [Member] | Total commercial lending [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	398,000,000		481,000,000
Substandard [Member] | Total commercial lending [Member] | Equipment Lease Financing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	219,000,000		150,000,000
Doubtful [Member] | Total commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Purchased impaired loans	11,000,000		6,000,000
Total Loans	194,000,000		102,000,000
Doubtful [Member] | Total commercial lending [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	163,000,000		90,000,000
Doubtful [Member] | Total commercial lending [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	11,000,000		5,000,000
Doubtful [Member] | Total commercial lending [Member] | Equipment Lease Financing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans - Excluding Purchased Impaired Loans	$ 9,000,000		$ 1,000,000

[1] Our consolidated assets at June 30, 2016 included the following for which we have elected the fair value option: Federal funds sold and resale agreements of $137 million, Loans held for sale of $2.1 billion, Loans of $.9 billion, and Other assets of $349 million. Our consolidated assets at December 31, 2015 included the following for which we have elected the fair value option: Federal funds sold and resale agreements of $137 million, Loans held for sale of $1.5 billion, Loans of $.9 billion, and Other assets of $521 million.