Commitments and Guarantees (Resale and Repurchase Agreements) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Offsetting Assets [Line Items]
Gross Resale Agreements	$ 1,077	$ 1,542
Net Resale Agreements	1,077	1,542
Securities Collateral Held Under Master Netting Agreements	987	1,453
Net Amounts	90	89
Offsetting Liabilities [Line Items]
Gross Repurchase Agreements	3,055	4,183
Net Repurchase Agreements	3,055	4,183
Securities Collateral Pledged Under Master Netting Agreements	2,178	3,166
Net Amounts	877	1,017
Municipalities, pension plans and certain trusts and insurance companies [Member]
Offsetting Liabilities [Line Items]
Net Repurchase Agreements	873	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	$ 84	$ 89