Commitments, Contingencies, And Guarantees (Narrative) (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Carrying value of limited partnerships and partially-owned investment companies included in other investments	$ 2,200,000,000
Funding commitments relating to limited partnerships and partially-owned investment companies	992,000,000
Repurchase obligations	1,402,000,000	1,402,000,000
Securities lending payable	1,034,000,000	1,331,000,000
Securities lending collateral	1,033,000,000	1,330,000,000
Unrecognized tax benefits	23,000,000us-gaap_UnrecognizedTaxBenefits
Derivative liability subject to a master netting agreement	$ 4,000,000	$ 34,000,000

Carrying value of limited partnerships and partially-owned investment companies included in other investments.

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- Definition

Funding commitments relating to limited partnerships and partially-owned investment companies included in other investments.

+ References

No definition available.

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Fair value, after effects of master netting arrangements, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset offset against the right to receive collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226016-175313

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-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (e)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=d3e41678-113959

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- Definition

The fair value of collateral received by the entity associated with securities borrowed that must be returned if the counterparty fulfills its obligations. It appears on the balance sheet as a liability and has a corresponding asset that appears on the balance sheet called Securities Received as Collateral.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.15)

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-Glossary Collateral

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The carrying amount (fair value) as of the balance sheet date of securities held that had been pledged by counterparties under financing and lending arrangements, pursuant to which the entity has the right by agreement or custom to sell or re-pledge such securities.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5086-111524

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(1))

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-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

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-Topic 210

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-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226008-175313

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph 1

-Article 9

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-Topic 210

-SubTopic 20

-Section 45

-Paragraph 11

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-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(m)(1)(a)(i))

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

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-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)

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