Financial Guaranty Contracts Accounted for as Credit Derivatives - Net Change in Unrealized Gains (Losses) on Credit Derivatives By Sector (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Credit Derivatives
Net unrealized gains (losses)	$ 88	[1]	$ 160	[1]	$ (142)	[1]	$ (450)	[1]
Net change in fair value of credit derivatives	103		74		(108)		(518)
Film securitization [Member]
Credit Derivatives
Net unrealized gains (losses)			(127)
Payments from Termination of Financial Guaranty Contracts Accounted for as Credit Derivatives			120
Net change in fair value of credit derivatives			(7)
Pooled corporate
Credit Derivatives
Net unrealized gains (losses)	64		(34)		6		(139)
U.S. RMBS
Credit Derivatives
Net unrealized gains (losses)	5		14		(135)		(443)
CMBS
Credit Derivatives
Net unrealized gains (losses)	2		(1)		2		(4)
Other
Credit Derivatives
Net unrealized gains (losses)	17	[2]	181	[2]	(15)	[2]	136	[2]
Guaranteed Interest Rate Swaps
Credit Derivatives
Net unrealized gains (losses)					$ (20)

[1] Except for net estimated credit impairments (i.e., net expected loss to be paid as discussed in Note 5), the unrealized gains and losses on credit derivatives are expected to reduce to zero as the exposure approaches its maturity date. With considerable volatility continuing in the market, unrealized gains (losses) on credit derivatives may fluctuate significantly in future periods.

[2] “Other” includes all other U.S. and international asset classes, such as commercial receivables, international infrastructure, international RMBS securities, and pooled infrastructure securities.