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		Jun. 30, 2016	Dec. 31, 2015
Foreign Exchange Future [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision		$ 1,258	$ 1,029
Cross Currency Swap [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		0	0
Fair Value, Asset		0	0
Notional Value/Payment Provision		95	95
Futures contracts on notes and bonds [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision		1,249	751
Convertibles and Bonds with Warrants Attached [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision	[1]	6	40
Investment And Embedded Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		20	43
Notional Value/Payment Provision		2,608	1,915
Single-Stock Future [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision	[2]	1,225	1,197
Other Derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision		277	15
Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision		1,502	1,212
Guaranteed Living Benefits [Member]
Derivatives, Fair Value [Line Items]
Notional Value/Payment Provision	[3]	1,511	1,155
Other Assets [Member] | Foreign Exchange Future [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		10	7
Other Assets [Member] | Futures contracts on notes and bonds [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		8	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		7	0
Other Assets [Member] | Other Derivative Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset		7	0
Other Assets [Member] | Guaranteed Living Benefits [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset	[3]	0	0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Foreign Exchange Future [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(27)	(11)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Futures contracts on notes and bonds [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability		(44)	(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		(71)	(13)
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Single-Stock Future [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[2]	(4)	(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		(14)	(10)
Fixed Maturities Available For Sale [Member] | Convertibles and Bonds with Warrants Attached [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Asset	[1]	2	31
Accounts Payable Future Policy Benefits [Member] | Guaranteed Living Benefits [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Liability	[3]	$ (1,256)	$ (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.