Commitments and Guarantees (Analysis of Commercial Mortgage Recourse Obligations) (Details) (Recourse Obligations [Member], Commercial Mortgage [Member], USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011
Recourse Obligations [Member] \| Commercial Mortgage [Member]
Loss Contingencies [Line Items]
Reserves, Beginning balance	$ 47	$ 54
Reserve adjustments, net	4	2
Losses - loan repurchases and settlements	(8)	(7)
Reserves, Ending balance	$ 43	$ 49

The charge against earnings in the period to increase loss contingency liabilities, net of any adjustments to reduce previously estimated charges.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration