Derivative Instruments (Summary Of Effect Of Derivative Instruments On Consolidated Statement Of Operations) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Derivatives In Fair Value Hedging Relationships [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Income on Derivative	$ (6)	$ (42)	$ (40)
Gain (Loss) Recognized in Income on Hedged item	6	41	32
Net Gain (Loss) Recognized in Income	(9)	(6)	(5)
Derivatives In Fair Value Hedging Relationships [Member] | Interest Rate Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Income on Derivative	(8)	(42)
Gain (Loss) Recognized in Income on Hedged item	8	41
Net Gain (Loss) Recognized in Income		(1)
Derivatives In Fair Value Hedging Relationships [Member] | Interest Rate Swaps [Member] | Interest Income (Expense) [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(9)	(5)	2
Derivatives In Fair Value Hedging Relationships [Member] | Interest Rate Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Income on Derivative			(57)
Gain (Loss) Recognized in Income on Hedged item			48
Net Gain (Loss) Recognized in Income			(9)
Derivatives In Fair Value Hedging Relationships [Member] | Currency Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Income on Derivative	2
Gain (Loss) Recognized in Income on Hedged item	(2)
Derivatives In Fair Value Hedging Relationships [Member] | Currency Swaps [Member] | Interest Income (Expense) [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income			1
Derivatives In Fair Value Hedging Relationships [Member] | Currency Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Income on Derivative			17
Gain (Loss) Recognized in Income on Hedged item			(16)
Net Gain (Loss) Recognized in Income			1
Derivatives Not Designated As Hedging Instruments [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(2,960)	(912)	1,554
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(193)		17
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income		(138)
Derivatives Not Designated As Hedging Instruments [Member] | Currency Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(1)		(1)
Derivatives Not Designated As Hedging Instruments [Member] | Currency Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income		10
Derivatives Not Designated As Hedging Instruments [Member] | Insured Credit Default Swaps [Member] | Unrealized Gains (Losses) On Insured Derivatives [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(389)	(596)	1,660
Derivatives Not Designated As Hedging Instruments [Member] | Insured Credit Default Swaps [Member] | Realized Gains (Losses) And Other Settlements On Insured Derivatives [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(2,371)	(162)	(167)
Derivatives Not Designated As Hedging Instruments [Member] | Insured Swaps [Member] | Unrealized Gains (Losses) On Insured Derivatives [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income		2	1
Derivatives Not Designated As Hedging Instruments [Member] | Non-Insured Credit Default Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(2)		17
Derivatives Not Designated As Hedging Instruments [Member] | Non-Insured Credit Default Swaps [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income		(1)
Derivatives Not Designated As Hedging Instruments [Member] | Non-Insured Credit Default Swaps-VIE [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	12	(24)
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps-VIE [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	53	25	13
Derivatives Not Designated As Hedging Instruments [Member] | Other [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(6)	(17)	(8)
Derivatives Not Designated As Hedging Instruments [Member] | Other [Member] | Unrealized Gains (Losses) On Insured Derivatives [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(52)	(13)	(11)
Derivatives Not Designated As Hedging Instruments [Member] | All Other-VIE [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	(8)	(16)
Derivatives Not Designated As Hedging Instruments [Member] | Credit Linked Notes [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income			27
Derivatives Not Designated As Hedging Instruments [Member] | Credit Linked Notes [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income		18
Derivatives Not Designated As Hedging Instruments [Member] | Total Return Swap [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income			6
Derivatives Not Designated As Hedging Instruments [Member] | Currency Swaps -VIE [Member] | Net Gains (Losses) On Financial Instruments At Fair Value And Foreign Exchange-VIE [Member]
Derivative [Line Items]
Net Gain (Loss) Recognized in Income	$ (3)