Commitments, Contingencies, and Guarantees - Narrative (Details) (Residential Mortgage, USD $)	9 Months Ended
	Sep. 30, 2013 Loan
Residential Mortgage
Representations and Warranties
Residential Mortgage Loans Sold, Unpaid Principal Balance	$ 3,000,000,000
Number of Mortgage Loans Repurchased	6
Repurchased Mortgage Loans, Unpaid Principal Balance	2,300,000
Number of Mortgage Loans Repurchased, Delinquent	3
Number of Mortgage Loans Repurchased, Pending	2
Pending Repurchase Mortgage Loans, Unpaid Principal Balance	$ 600,000
Current Residential Mortgage Loans Serviced for Third Parties as Percentage of Total	99.00%