Derivative Instruments (Credit Derivatives Sold) (Details) (Insurance Operations [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Derivative [Line Items]
Total Notional Value of Credit Derivatives	$ 67,359	$ 73,551
Total Fair Value of Credit Derivatives	(5,038)	(5,343)
Insured Credit Default Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	59,775	65,557
Total Fair Value of Credit Derivatives	(4,416)	(4,716)
Weighted Average Remaining Expected Maturity	5.7 Years	5.6 Years
Non-Insured Credit Default Swaps-VIE [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	643	643
Total Fair Value of Credit Derivatives	(525)	(527)
Weighted Average Remaining Expected Maturity	3.4 Years	3.6 Years
Insured Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	6,746	7,156
Total Fair Value of Credit Derivatives	(9)	(9)
Weighted Average Remaining Expected Maturity	20.6 Years	19.7 Years
All Other [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	195	195
Total Fair Value of Credit Derivatives	(88)	(91)
Weighted Average Remaining Expected Maturity	2.6 Years	2.8 Years
AAA [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	11,017	15,475
Total Fair Value of Credit Derivatives	(74)	(114)
AAA [Member] | Insured Credit Default Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	11,017	15,475
AA [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	10,209	12,229
Total Fair Value of Credit Derivatives	(91)	(116)
AA [Member] | Insured Credit Default Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	9,545	12,065
AA [Member] | Insured Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	664	164
A [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	9,329	10,606
Total Fair Value of Credit Derivatives	(206)	(205)
A [Member] | Insured Credit Default Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	5,363	6,336
A [Member] | Insured Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	3,966	4,270
BBB [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	14,629	16,631
Total Fair Value of Credit Derivatives	(1,172)	(1,355)
BBB [Member] | Insured Credit Default Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	12,606	14,042
BBB [Member] | Insured Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	2,023	2,589
Below BBB [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	22,175	18,610
Total Fair Value of Credit Derivatives	(3,495)	(3,553)
Below BBB [Member] | Insured Credit Default Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	21,244	17,639
Below BBB [Member] | Non-Insured Credit Default Swaps-VIE [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	643	643
Below BBB [Member] | Insured Swaps [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	93	133
Below BBB [Member] | All Other [Member]
Derivative [Line Items]
Total Notional Value of Credit Derivatives	$ 195	$ 195