Commitments and Guarantees (Resale and Repurchase Agreements) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Offsetting Assets [Line Items]
Gross Resale Agreements	$ 1,548	$ 1,646
Net Resale Agreements	1,548	1,646
Securities Collateral Held Under Master Netting Agreements	1,474	1,569
Net Amounts	74	77
Offsetting Liabilities [Line Items]
Gross Repurchase Agreements	2,132	3,406
Net Repurchase Agreements	2,132	3,406
Securities Collateral Pledged Under Master Netting Agreements	1,332	2,580
Net Amounts	800	826
Accrued Interest Expense [Member]
Offsetting Liabilities [Line Items]
Net Repurchase Agreements	0	0
Long Term Repurchase Agreements [Member]
Offsetting Liabilities [Line Items]
Net Repurchase Agreements	0	0
Accrued Interest Income [Member]
Offsetting Assets [Line Items]
Net Resale Agreements	$ 0	$ 1