Commitments, Contingencies, Guarantees, and Others - Litigation (Details) (USD $)			1 Months Ended			3 Months Ended	1 Months Ended				3 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 Interchange Litigation	Jan. 31, 2014 Intellectual Ventures Corp claim	Dec. 31, 2013 Intellectual Ventures Corp claim	Jul. 31, 2012 Pending Litigation Interchange Litigation	Mar. 31, 2008 Pending Litigation Interchange Litigation	Apr. 30, 2014 Pending Litigation Intellectual Ventures Corp patent	Dec. 31, 2013 Pending Litigation Intellectual Ventures Corp patent	Feb. 28, 2009 GreenPoint Subsidiary Pending Litigation U.S. Bank Litigation Plaintiff MortgageLoan Contract	Sep. 30, 2010 GreenPoint Subsidiary Pending Litigation DBSP Litigation	Jul. 31, 2012 GreenPoint Subsidiary Pending Litigation FHFA Litigation summon trust	Jul. 31, 2013 GreenPoint Subsidiary Pending Litigation LXS Trust Litigation
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss	$ 250,000,000
Litigation settlement, attributable to reporting entity and third party					6,600,000,000
Litigation settlement, attributable to reporting entity and third party, percent of transactions					0.10%
Litigation settlement, attributable to reporting entity and third party, period of payment of settlement					8 months
Loss accrual increase (decrease)						(91,000,000)
Indemnification guarantees fair value		0
Number of contracts breached									2
Number of mortgage loans sold to third party under litigation									30,000
Mortgage loans sold to third party, face amount under litigation									$ 1,800,000,000	$ 353,000,000	$ 3,400,000,000	$ 915,000,000
Number of plaintiffs									2
Number of summons filed											3
Number of residential mortgage backed securities trusts											3
Number of claims dismissed			1	2
Number of patents not infringed							2	1