Financial Instruments Investment Segment and Holding Company Narrative (Details) (Investment Segment [Member], Investment Funds [Member], USD $)	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Investment Segment [Member] \| Investment Funds [Member]
Derivative [Line Items]
Maximum payout amounts relating to put options written	$ 630,000,000		$ 7,900,000,000
Covered put options on existing short positions			6,800,000,000
Realized and unrealized gain (loss) on derivatives, net	1,000,000	180,000,000
Fair value of derivative instruments with credit-risk related contingent features in a liability position	662,000,000		84,000,000
Cash collateral posted for derivative positions	$ 270,000,000		$ 148,000,000

Open Option Contracts Written, Covered Put Options on Existing Short Positions

No definition available.

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- Definition

The maximum payout of the open option contracts written for the investment.

+ References

No definition available.

+ Details

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- Definition

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4H

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624258-113959

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- Definition

Fair value of credit risk derivative liability.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4K

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5708775-113959

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- Details

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- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

+ Details

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