Expected Losses to be Paid (Roll Forward of Estimated Benefit From Recoveries) (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
R&W development and accretion of discount during period	$ 179		$ 1,038
Gross R&W amounts recovered	485		1,212
Prime first lien
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	3		1
R&W development and accretion of discount during period	1		2
R&W recovered during period	0	[1]	0	[1]
Future net R&W benefit at the end of the period	4	[2]	3
Alt-A first lien
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	407		149
R&W development and accretion of discount during period	40		260
R&W recovered during period	(69)	[1]	(2)	[1]
Future net R&W benefit at the end of the period	378	[2]	407
First mortgage, option adjustable rate mortgage
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	725		312
R&W development and accretion of discount during period	89		508
R&W recovered during period	(223)	[1]	(95)	[1]
Future net R&W benefit at the end of the period	591	[2]	725
First mortgage, subprime
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	101		27
R&W development and accretion of discount during period	8		74
R&W recovered during period	0	[1]	0	[1]
Future net R&W benefit at the end of the period	109	[2]	101
Total first lien
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	1,236		489
R&W development and accretion of discount during period	138		844
R&W recovered during period	(292)	[1]	(97)	[1]
Future net R&W benefit at the end of the period	1,082	[2]	1,236
Closed end second lien and HELOCs
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	224		178
R&W development and accretion of discount during period	5		55
R&W recovered during period	(91)	[1]	(9)	[1]
Future net R&W benefit at the end of the period	138	[2]	224
HELOCs
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	190		1,004
R&W development and accretion of discount during period	36		139
R&W recovered during period	(76)	[1]	(953)	[1]
Future net R&W benefit at the end of the period	150	[2]	190
Second lien
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	414		1,182
R&W development and accretion of discount during period	41		194
R&W recovered during period	(167)	[1]	(962)	[1]
Future net R&W benefit at the end of the period	288	[2]	414
U.S. RMBS
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	1,650		1,671
R&W development and accretion of discount during period	179		1,038
R&W recovered during period	(459)	[1]	(1,059)	[1]
Future net R&W benefit at the end of the period	$ 1,370	[2]	$ 1,650

[1] Gross amounts recovered were $485 million and $1,212 million for years ended December 31, 2012 and 2011, respectively.

[2] Includes excess spread that the Company will receive as salvage as a result of a settlement agreement with a R&W provider.