Commitments, Contingencies, And Guarantees (Balance Sheet Locations, Fair Values In Asset Or (Liability) Position, And Notional Values/Payment Provisions Of Derivative Instruments) (Detail) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Foreign Exchange Future [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision		$ 903	$ 1,029
Cross Currency Swap [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision		95	95
Futures contracts on notes and bonds [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision		1,235	751
Convertibles and Bonds with Warrants Attached [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision	[1]	7	40
Investment And Embedded Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		14	43
Notional Value/Payment Provision		2,240	1,915
Single-Stock Future [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision	[2]	1,171	1,197
Other Derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision		71	15
Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision		1,242	1,212
Guaranteed Living Benefits [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision	[3]	1,377	1,155
Other Assets [Member] | Foreign Exchange Future [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		6	7
Other Assets [Member] | Futures contracts on notes and bonds [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		5	5
Other Assets [Member] | Single-Stock Future [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset	[2]	0	0
Other Assets [Member] | Other Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		0	0
Other Assets [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		0	0
Other Assets [Member] | Guaranteed Living Benefits [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset	[3]		0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Foreign Exchange Future [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(19)	(11)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Futures contracts on notes and bonds [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(4)	(2)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Convertibles and Bonds with Warrants Attached [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[1]	0	0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Investment And Embedded Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(23)	(13)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Single-Stock Future [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[2]	(36)	(4)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(10)	(6)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(46)	(10)
Fixed Maturities Available For Sale [Member] | Convertibles and Bonds with Warrants Attached [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset	[1]	3	31
Accounts Payable Future Policy Benefits [Member] | Guaranteed Living Benefits [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[3]	$ (1,122)	$ (888)

[1] Includes fair value of embedded derivatives.

[2] Related to GMDB and GLB blocks of business.

[3] Includes both future policy benefits reserves and fair value derivative adjustment. Refer to Note 5 for additional information. Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.