Derivative Instruments (Narrative) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Derivative [Line Items]
Maximum amount of future guarantee payments	$ 24,500,000,000
Insured derivatives ceded under reinsurance agreements	59,000,000
Cash collateral posted to derivative counterparties	160,000,000		285,000,000
Securities posted as collateral to derivative counterparties	42,000,000		0
Number of credit support annexes	1		1
Fair value of Credit Support Annex	4,000,000		4,000,000
Amount of counterparty netting	42,000,000		90,000,000
Derivative assets, after counterparty netting	13,000,000		12,000,000
Other assets and other assets of consolidated VIEs, after counterparty netting and embedded reclass	4,000,000		4,000,000
Counterparty netting	42,000,000		90,000,000
Derivative liabilities, after counterparty netting and posting of cash collateral	1,200,000,000		3,100,000,000
Derivative Liabilities [Member]
Derivative [Line Items]
Cash collateral posted to derivative counterparties	123,000,000		203,000,000
Total derivative liabilities	1,347,000,000	[1]	3,425,000,000	[1]
Other Liabilities [Member]
Derivative [Line Items]
Cash collateral posted to derivative counterparties	16,000,000		16,000,000
Other Assets [Member]
Derivative [Line Items]
Cash collateral posted to derivative counterparties	21,000,000		66,000,000
Medium Term Notes And Other Investments [Member]
Derivative [Line Items]
Embedded derivative assets	9,000,000		8,000,000
Medium Term Notes And Other Investments [Member] | Embedded [Member]
Derivative [Line Items]
Total derivative liabilities	$ 19,000,000		$ 36,000,000

[1] In accordance with the accounting guidance for derivative instruments and hedging activities, the balance sheet location of the Company’s embedded derivative instruments is determinedby the location of the related host contract.