Outstanding Loans and Leases - Purchased Credit-Impaired Loans (Details) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Accretable yield, beginning of period	$ 6,219,000,000	$ 6,694,000,000
Accretion	(265,000,000)	(819,000,000)
Disposals/transfers	(241,000,000)	(424,000,000)
Reclassifications from nonaccretable difference	242,000,000	504,000,000
Accretable yield, September 30, 2014	5,955,000,000	5,955,000,000
Purchased credit impaired loans sold	1,300,000,000	1,900,000,000
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing receivable allowance sold	$ 131,000,000	$ 317,000,000