Commitments and Guarantees (Resale and Repurchase Agreements) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Offsetting Assets [Line Items]
Gross Resale Agreements	$ 1,646	$ 1,542
Net Resale Agreements	1,646	1,542
Securities Collateral Held Under Master Netting Agreements	1,569	1,453
Net Amounts	77	89
Offsetting Liabilities [Line Items]
Gross Repurchase Agreements	3,406	4,183
Net Repurchase Agreements	3,406	4,183
Securities Collateral Pledged Under Master Netting Agreements	2,580	3,166
Net Amounts	826	1,017
Municipalities, pension plans and certain trusts and insurance companies [Member]
Offsetting Liabilities [Line Items]
Net Repurchase Agreements	826	966
Long Term Repurchase Agreements [Member]
Offsetting Liabilities [Line Items]
Net Repurchase Agreements	0	50
Accrued Interest Income [Member]
Offsetting Assets [Line Items]
Net Resale Agreements	1	1
Long Term Resale Agreements [Member]
Offsetting Assets [Line Items]
Net Resale Agreements	$ 77	$ 89