Derivative Instruments (Total Fair Value Of Company's Derivative Assets And Liabilities By Instrument And Balance Sheet Location, Before Counterparty Netting) (Detail) (Not Designated as Hedging Instrument [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Derivative [Line Items]
Derivative notional amount	$ 17,750		$ 31,316
Derivative Liabilities [Member]
Derivative [Line Items]
Derivative Liabilities, Not designated, Fair Value	567	[1]	(1,347)	[1]
Derivative Assets [Member]
Derivative [Line Items]
Derivative Assets, Not designated, Fair Value	77	[1]	55	[1]
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative notional amount	1,477		1,495
Interest Rate Swap [Member] | Derivative Liabilities [Member]
Derivative [Line Items]
Derivative Liabilities, Not designated, Fair Value	(211)	[1]	(165)	[1]
Interest Rate Swap [Member] | Other Assets [Member]
Derivative [Line Items]
Derivative Assets, Not designated, Fair Value	69	[1]	46	[1]
Credit Default Swap [Member]
Derivative [Line Items]
Derivative notional amount	11,276		23,954
Credit Default Swap [Member] | Derivative Liabilities [Member]
Derivative [Line Items]
Derivative Liabilities, Not designated, Fair Value	(284)	[1]	(1,132)	[1]
Insured Swaps [Member]
Derivative [Line Items]
Derivative notional amount	4,111		4,945
Insured Swaps [Member] | Derivative Liabilities [Member]
Derivative [Line Items]
Derivative Liabilities, Not designated, Fair Value	(4)	[1]	(5)	[1]
Interest Rate Swaps Embedded [Member]
Derivative [Line Items]
Derivative notional amount	457		496
Interest Rate Swaps Embedded [Member] | Medium Term Notes [Member]
Derivative [Line Items]
Derivative Assets, Not designated, Fair Value	8	[1]	9	[1]
Derivative Liabilities, Not designated, Fair Value	(23)	[1]	(19)	[1]
Currency Swaps Vie [Member]
Derivative [Line Items]
Derivative notional amount	93		99
Currency Swaps Vie [Member] | Derivative Liabilities V I E [Member]
Derivative [Line Items]
Derivative Liabilities, Not designated, Fair Value	(7)	[1]	(11)	[1]
All Other [Member]
Derivative [Line Items]
Derivative notional amount	83		36
All Other [Member] | Derivative Liabilities [Member]
Derivative [Line Items]
Derivative Liabilities, Not designated, Fair Value	(38)	[1]	(15)	[1]
All Other V I E [Member]
Derivative [Line Items]
Derivative notional amount	241		280
All Other Embedded [Member]
Derivative [Line Items]
Derivative notional amount	12		11
All Other Embedded [Member] | Derivative Liabilities Other Investments [Member]
Derivative [Line Items]
Derivative Liabilities, Not designated, Fair Value	$ 0	[1]

[1] In accordance with the accounting guidance for derivative instruments and hedging activities, the balance sheet location of the Companys embedded derivative instruments is determined by the location of the related host contract