Commitments and Guarantees (Resale and Repurchase Agreements) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Offsetting Assets [Line Items]
Gross Resale Agreements	$ 637	$ 1,082
Net Resale Agreements	637	1,082
Securities Collateral Held Under Master Netting Agreements	563	1,008
Net Amounts	74	74
Offsetting Liabilities [Line Items]
Gross Repurchase Agreements	1,231	1,767
Net Repurchase Agreements	1,231	1,767
Securities Collateral Pledged Under Master Netting Agreements	532	1,014
Net Amounts	699	753
Long Term Repurchase Agreements [Member]
Offsetting Liabilities [Line Items]
Net Repurchase Agreements	$ 0	$ 0