Variable Interest Entities and Securitization Activities (Transfers of Assets Treated as Secured Financings) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Commercial Mortgage Loans
Assets, carrying value	$ 0	$ 121
Liabilities, carrying value	0	121
Credit-Linked Notes
Assets, carrying value	283	383
Liabilities, carrying value	222	339
Equity-Linked Transactions
Assets, carrying value	422	1,243
Liabilities, carrying value	405	1,214
Other
Assets, carrying value	29	75
Liabilities, carrying value	$ 28	$ 74

Carrying amount of liabilities associated with financial assets accounted for as secured borrowings recognized in the transferor's statement of financial position at the end of each period presented.

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

-Publisher FASB

-Name Accounting Standards Codification

-Section 50

-Paragraph 1A

-Subparagraph (b)(1)

-SubTopic 30

-Topic 860

-URI http://asc.fasb.org/extlink&oid=6862952&loc=SL6224234-111729

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4/FIN46(R)-8

-Paragraph B12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Name:	us-gaap_TransfersAccountedForAsSecuredBorrowingsAssociatedLiabilitiesCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant