Derivative Instruments (Credit Derivatives Sold) (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Derivative [Line Items]
Derivative notional amount	$ 22,513	$ 31,316
Insurance Operations [Member]
Derivative [Line Items]
Derivative notional amount	20,082	28,935
Total fair value of credit derivatives	(335)	(1,152)
Insurance Operations [Member] | Credit Default Swap [Member]
Derivative [Line Items]
Weighted average remaining expected maturity	2 years 3 months 18 days	2 years 7 months 6 days
Derivative notional amount	15,986	23,954
Total fair value of credit derivatives	(332)	(1,132)
Insurance Operations [Member] | Insured Swaps [Member]
Derivative [Line Items]
Weighted average remaining expected maturity	16 years 10 months 24 days	18 years 6 months 0 days
Derivative notional amount	4,096	4,945
Total fair value of credit derivatives	(3)	(5)
Insurance Operations [Member] | Other Credit Derivatives [Member]
Derivative [Line Items]
Weighted average remaining expected maturity		28 years 0 months 0 days
Derivative notional amount	0	36
Total fair value of credit derivatives	0	(15)
Credit Rating Aaa [Member] | Insurance Operations [Member]
Derivative [Line Items]
Derivative notional amount	6,938	7,406
Total fair value of credit derivatives	(2)	(2)
Credit Rating Aaa [Member] | Insurance Operations [Member] | Credit Default Swap [Member]
Derivative [Line Items]
Derivative notional amount	6,938	7,406
Credit Rating Aaa [Member] | Insurance Operations [Member] | Insured Swaps [Member]
Derivative [Line Items]
Derivative notional amount	0	0
Credit Rating Aaa [Member] | Insurance Operations [Member] | Other Credit Derivatives [Member]
Derivative [Line Items]
Derivative notional amount	0	0
Credit Rating Aa [Member] | Insurance Operations [Member]
Derivative [Line Items]
Derivative notional amount	635	2,049
Total fair value of credit derivatives	0	0
Credit Rating Aa [Member] | Insurance Operations [Member] | Credit Default Swap [Member]
Derivative [Line Items]
Derivative notional amount	560	1,972
Credit Rating Aa [Member] | Insurance Operations [Member] | Insured Swaps [Member]
Derivative [Line Items]
Derivative notional amount	75	77
Credit Rating Aa [Member] | Insurance Operations [Member] | Other Credit Derivatives [Member]
Derivative [Line Items]
Derivative notional amount	0	0
Credit Rating A [Member] | Insurance Operations [Member]
Derivative [Line Items]
Derivative notional amount	4,004	4,350
Total fair value of credit derivatives	(2)	(3)
Credit Rating A [Member] | Insurance Operations [Member] | Credit Default Swap [Member]
Derivative [Line Items]
Derivative notional amount	968	1,068
Credit Rating A [Member] | Insurance Operations [Member] | Insured Swaps [Member]
Derivative [Line Items]
Derivative notional amount	3,036	3,282
Credit Rating A [Member] | Insurance Operations [Member] | Other Credit Derivatives [Member]
Derivative [Line Items]
Derivative notional amount	0	0
Credit Rating Bbb [Member] | Insurance Operations [Member]
Derivative [Line Items]
Derivative notional amount	5,689	9,138
Total fair value of credit derivatives	(31)	(78)
Credit Rating Bbb [Member] | Insurance Operations [Member] | Credit Default Swap [Member]
Derivative [Line Items]
Derivative notional amount	4,704	7,552
Credit Rating Bbb [Member] | Insurance Operations [Member] | Insured Swaps [Member]
Derivative [Line Items]
Derivative notional amount	985	1,586
Credit Rating Bbb [Member] | Insurance Operations [Member] | Other Credit Derivatives [Member]
Derivative [Line Items]
Derivative notional amount	0	0
Credit Rating Below Investment Grade [Member] | Insurance Operations [Member]
Derivative [Line Items]
Derivative notional amount	2,816	5,992
Total fair value of credit derivatives	(300)	(1,069)
Credit Rating Below Investment Grade [Member] | Insurance Operations [Member] | Credit Default Swap [Member]
Derivative [Line Items]
Derivative notional amount	2,816	5,956
Credit Rating Below Investment Grade [Member] | Insurance Operations [Member] | Insured Swaps [Member]
Derivative [Line Items]
Derivative notional amount	0	0
Credit Rating Below Investment Grade [Member] | Insurance Operations [Member] | Other Credit Derivatives [Member]
Derivative [Line Items]
Derivative notional amount	$ 0	$ 36