Expected Loss to be Paid - Narrative (Details) (USD $)	3 Months Ended				12 Months Ended		1 Months Ended
	Mar. 31, 2015 risk		Mar. 31, 2014		Dec. 31, 2014		Nov. 30, 2014	Dec. 31, 2013		Sep. 12, 2014 Transaction	Oct. 10, 2013 Transaction	May 06, 2013	Apr. 14, 2011	May 08, 2012
Schedule of Expected Losses to be Paid [Line Items]
Number of risks subject to R&W recovery	30				29
Risks subject to R&W recovery, related net debt service amount	$ 2,100,000,000				2,100,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	1,154,000,000	[1]	984,000,000	[1]	1,169,000,000	[1]		982,000,000	[1]
Economic loss development after recoveries for R&W	3,000,000		(12,000,000)
Net par amount outstanding	389,099,000,000	[2]			403,729,000,000	[3]
Minimum [Member]
Schedule of Expected Losses to be Paid [Line Items]
Discount factor (as a percent)	0.00%				0.00%
Maximum [Member]
Schedule of Expected Losses to be Paid [Line Items]
Discount factor (as a percent)	2.89%				2.95%
Puerto Rico [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	4,940,000,000				4,939,000,000
Gross par outstanding	6,036,000,000				6,035,000,000
RMBS [Member]
Schedule of Expected Losses to be Paid [Line Items]
Amount of liabilities agreed to be paid by entities providing R&W for transaction in which the Company provided insurance	4,200,000,000
RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Maximum number of payments behind to be considered performing borrower	1
Estimated benefit from loan repurchases related to breaches of R&W included in net expected loss estimates	245,000,000	[4]	721,000,000	[4]	317,000,000			712,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	570,000,000	[1]	480,000,000	[1]	584,000,000	[1]		493,000,000	[1]
Economic loss development after recoveries for R&W	(4,000,000)		10,000,000
Net par amount outstanding	9,078,000,000				9,417,000,000
RMBS [Member] | United States [Member] | Option ARM [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR	15.00%	[5],[6]			15.00%	[5],[6]
RMBS [Member] | United States [Member] | Subprime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR	15.00%	[5],[6]			15.00%	[5],[6]
RMBS [Member] | United States [Member] | Alt-A [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR					15.00%	[5],[6]
RMBS [Member] | United States [Member] | Closed-end [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR	15.00%	[5],[6]			15.00%	[5],[6]
RMBS [Member] | United States [Member] | Minimum [Member] | Alt-A [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR	15.00%	[5],[6]
RMBS [Member] | United States [Member] | Minimum [Member] | HELOCs [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR	10.00%	[5],[6]			15.00%	[5],[6]
RMBS [Member] | United States [Member] | Maximum [Member] | Alt-A [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR	22.40%	[5],[6]
RMBS [Member] | United States [Member] | Maximum [Member] | HELOCs [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR	23.20%	[5],[6]			21.80%	[5],[6]
HELOCs [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Initial period for which borrower can pay only interest payments	10 years
Percentage of expected default loans reaching amortization period	7.50%
Trust Preferred Securities (TruPS) [Member]
Schedule of Expected Losses to be Paid [Line Items]
Percentage of installment premiums denominated in currencies other than the U.S. dollar	72.00%
Liability for unpaid claims and claims adjustment expense, net largest single loss	14,000,000	[1]	32,000,000	[1]	23,000,000	[1]		51,000,000	[1]
Economic loss development after recoveries for R&W	9,000,000		19,000,000	[7]
Net par amount outstanding	4,075,000,000				4,326,000,000
Triple-X Life Insurance Transaction [Member]
Schedule of Expected Losses to be Paid [Line Items]
Liability for unpaid claims and claims adjustment expense, net largest single loss	165,000,000	[1]	87,000,000	[1]	161,000,000	[1]		75,000,000	[1]
Economic loss development after recoveries for R&W	(5,000,000)		(13,000,000)
Net par amount outstanding	3,133,000,000				3,133,000,000
Manufactured Housing Loans [Member]
Schedule of Expected Losses to be Paid [Line Items]
Liability for unpaid claims and claims adjustment expense, net largest single loss	25,000,000
Net par amount outstanding	215,000,000
Student Loan [Member]
Schedule of Expected Losses to be Paid [Line Items]
Liability for unpaid claims and claims adjustment expense, net largest single loss	75,000,000
Economic loss development after recoveries for R&W	(8,000,000)
Net par amount outstanding	2,500,000,000
Asset-backed Student Loan [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	1,800,000,000
Public Finance Student Loan [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	700,000,000
Public Finance [Member]
Schedule of Expected Losses to be Paid [Line Items]
Liability for unpaid claims and claims adjustment expense, net largest single loss	352,000,000	[1]	338,000,000	[1]	348,000,000	[1]		321,000,000	[1]
Economic loss development after recoveries for R&W	(6,000,000)		(23,000,000)
Public Finance [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Liability for unpaid claims and claims adjustment expense, net largest single loss	310,000,000	[1]	281,000,000	[1]	303,000,000	[1]		264,000,000	[1]
Economic loss development after recoveries for R&W	(9,000,000)		(23,000,000)
Net par amount outstanding	313,444,000,000	[2]			322,123,000,000	[3]
Public Finance [Member] | Puerto Rico [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	4,900,000,000
Public Finance Stockton General Fund [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	117,000,000
Cancelled lease revenue bonds	40,000,000
Non-Infrastructure Public Finance [Member] | Spain [Member] | Sovereign and Sub Sovereign [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	331,000,000
Gross par outstanding	461,000,000
Non-Infrastructure Public Finance [Member] | Portugal [Member] | Sovereign and Sub Sovereign [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	102,000,000
Gross par outstanding	114,000,000
Non-Infrastructure Public Finance [Member] | Hungary [Member] | Sovereign and Sub Sovereign [Member]
Schedule of Expected Losses to be Paid [Line Items]
Gross par outstanding	465,000,000
Non-Infrastructure Public Finance [Member] | Spain, Hungry and Portugal [Member] | Sovereign and Sub Sovereign [Member]
Schedule of Expected Losses to be Paid [Line Items]
Liability for unpaid claims and claims adjustment expense, net largest single loss	42,000,000
Economic loss development after recoveries for R&W	(3,000,000)
Deutsche Bank [Member]
Schedule of Expected Losses to be Paid [Line Items]
Assets held under trust for reimbursement payment	78,000,000
Number of transactions terminated					1					2	1
Number of transactions insured	8
City of Detroit [Member] | Public Finance [Member] | United States [Member] | Unlimited Tax General Obligation [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	20,000,000
Guarantor obligation on un-exchanged balance, percent							15.50%
Louisville Arena Authority [Member] | Public Finance [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	336,000,000
BIG [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	17,860,000,000				18,247,000,000
BIG [Member] | Puerto Rico [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	4,671,000,000
BIG [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	5,472,000,000				5,643,000,000
BIG [Member] | Trust Preferred Securities (TruPS) [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	1,155,000,000				1,333,000,000
BIG [Member] | Triple-X Life Insurance Transaction [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	598,000,000				598,000,000
BIG [Member] | Manufactured Housing Loans [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	155,000,000
BIG [Member] | Asset-backed Student Loan [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	193,000,000
BIG [Member] | Public Finance Student Loan [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	90,000,000
BIG [Member] | Public Finance [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	7,942,000,000				7,850,000,000
BIG [Member] | Public Finance [Member] | Puerto Rico [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	4,700,000,000
BIG [Member] | Non-Infrastructure Public Finance [Member] | Hungary [Member] | Sovereign and Sub Sovereign [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	439,000,000
BIG [Member] | Ballantyne Re Plc and Orkney Re I I Plc [Member] | Triple-X Life Insurance Transaction [Member]
Schedule of Expected Losses to be Paid [Line Items]
Number of transactions insured	2
Triple-X Life Insurance Transaction [Member] | Life Insurance [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	598,000,000
Refinancing Risk on Infrastructure Transactions [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	3,000,000,000
Financial insurance guaranty, infrastructure finance, possible claims requiring payment, gross before reinsurance	1,700,000,000
Refinancing Risk on Infrastructure Transactions [Member] | Minimum [Member]
Schedule of Expected Losses to be Paid [Line Items]
Estimated years for recoveries of infrastructure transactions	10 years
Refinancing Risk on Infrastructure Transactions [Member] | Maximum [Member]
Schedule of Expected Losses to be Paid [Line Items]
Estimated years for recoveries of infrastructure transactions	35 years
First Lien [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Number of delinquent payments	2
Projected loss assumptions, CDR, plateau rate, projection period	36 months
Projected loss assumptions, Final CDR, Period for voluntary prepayments to continue	12 months
Intermediate conditional default rate (as a percent)	5.00%
Number of scenarios weighted in estimating expected losses	5
Estimated benefit from loan repurchases related to breaches of R&W included in net expected loss estimates	162,000,000	[4]	570,000,000	[4]	232,000,000			569,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	569,000,000	[1]	593,000,000	[1]	595,000,000	[1]		620,000,000	[1]
Economic loss development after recoveries for R&W	2,000,000		17,000,000
First Lien [Member] | RMBS [Member] | United States [Member] | Option ARM [Member]
Schedule of Expected Losses to be Paid [Line Items]
Estimated benefit from loan repurchases related to breaches of R&W included in net expected loss estimates	(20,000,000)	[4]	152,000,000	[4]	15,000,000			173,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	(16,000,000)	[1]	(28,000,000)	[1]	(16,000,000)	[1]		(9,000,000)	[1]
Economic loss development after recoveries for R&W	(4,000,000)		15,000,000
Net par amount outstanding	374,000,000				407,000,000
First Lien [Member] | RMBS [Member] | United States [Member] | Subprime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Estimated benefit from loan repurchases related to breaches of R&W included in net expected loss estimates	87,000,000	[4]	146,000,000	[4]	109,000,000			118,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	293,000,000	[1]	295,000,000	[1]	303,000,000	[1]		304,000,000	[1]
Economic loss development after recoveries for R&W	1,000,000		7,000,000
Net par amount outstanding	3,935,000,000				4,051,000,000
First Lien [Member] | RMBS [Member] | United States [Member] | Prime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Estimated benefit from loan repurchases related to breaches of R&W included in net expected loss estimates	1,000,000	[4]	3,000,000	[4]	2,000,000			4,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	3,000,000	[1]	18,000,000	[1]	4,000,000	[1]		21,000,000	[1]
Economic loss development after recoveries for R&W	0		3,000,000
Net par amount outstanding	454,000,000				471,000,000
First Lien [Member] | RMBS [Member] | United States [Member] | Alt-A [Member]
Schedule of Expected Losses to be Paid [Line Items]
Estimated benefit from loan repurchases related to breaches of R&W included in net expected loss estimates	94,000,000	[4]	269,000,000	[4]	106,000,000			274,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	289,000,000	[1]	308,000,000	[1]	304,000,000	[1]		304,000,000	[1]
Economic loss development after recoveries for R&W	5,000,000		(8,000,000)
Net par amount outstanding	2,449,000,000				2,532,000,000
First Lien [Member] | Base Scenario [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, CDR, plateau rate, projection period	36 months
Period from plateau to intermediate conditional default rate (in months)	12 months
Period of constant intermediate conditional default rate (in months)	36 months
Intermediate conditional default rate as a percentage of plateau conditional default rate	20.00%
Final conditional default rate as a percentage of plateau conditional default rate	5.00%
Final conditional default rate, shortened term	3 months
Default from delinquentor rate, term	36 months
Projected loss assumptions, loss severity, subsequent period	18 months
Estimated loss severity rate, one through six months (as a percent)	18 months
Loss severity (as a percent)	40.00%
Projected loss assumptions, period to reach final loss severity rate	2 years 6 months
Projected loss assumptions, Final CDR, Period for voluntary prepayments to continue	8 years 3 months
Current conditional prepayment rate used in alternate scenario for loss estimate (as a percent)	15.00%
First Lien [Member] | Somewhat Stressful Environment [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, CDR, plateau rate, projection period	42 months
Projected loss assumptions, period to reach final loss severity rate	4 years 6 months
Increase in the plateau period used to calculate potential change in loss estimate (in months)	6 months
Projected loss assumptions, prior period to reach final loss severity rate	2 years 6 months
First Lien [Member] | Somewhat Stressful Environment [Member] | RMBS [Member] | United States [Member] | Option Adjustable Rate Mortgage and Alt-A Mortgage [Member]
Schedule of Expected Losses to be Paid [Line Items]
Loss severity (as a percent)	45.00%
First Lien [Member] | Somewhat Stressful Environment [Member] | RMBS [Member] | United States [Member] | Option ARM [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	2,000,000
First Lien [Member] | Somewhat Stressful Environment [Member] | RMBS [Member] | United States [Member] | Subprime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	72,000,000
First Lien [Member] | Somewhat Stressful Environment [Member] | RMBS [Member] | United States [Member] | Prime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	1,000,000
First Lien [Member] | Somewhat Stressful Environment [Member] | RMBS [Member] | United States [Member] | Alt-A [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	38,000,000
First Lien [Member] | Somewhat Stressful Environment [Member] | Subprime [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Loss severity (as a percent)	60.00%
First Lien [Member] | Somewhat Stressful Environment [Member] | Alt-A [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Loss severity (as a percent)	45.00%
First Lien [Member] | More Stressful Environment [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Period from plateau to intermediate conditional default rate (in months)	15 months
Projected loss assumptions, period to reach final loss severity rate	9 years
First Lien [Member] | More Stressful Environment [Member] | RMBS [Member] | United States [Member] | Option ARM [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	12,000,000
First Lien [Member] | More Stressful Environment [Member] | RMBS [Member] | United States [Member] | Subprime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	99,000,000
First Lien [Member] | More Stressful Environment [Member] | RMBS [Member] | United States [Member] | Prime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	4,000,000
First Lien [Member] | More Stressful Environment [Member] | RMBS [Member] | United States [Member] | Alt-A [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	84,000,000
First Lien [Member] | Somewhat Less Stressful Environment [Member] | RMBS [Member] | United States [Member] | Option ARM [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	14,000,000
First Lien [Member] | Somewhat Less Stressful Environment [Member] | RMBS [Member] | United States [Member] | Subprime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	11,000,000
First Lien [Member] | Somewhat Less Stressful Environment [Member] | RMBS [Member] | United States [Member] | Prime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	100,000
First Lien [Member] | Somewhat Less Stressful Environment [Member] | RMBS [Member] | United States [Member] | Alt-A [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	(400,000)
First Lien [Member] | Least Stressful Environment [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, CDR, plateau rate, projection period	30 months
Period from plateau to intermediate conditional default rate (in months)	9 months
Decrease in the plateau period used to calculate potential change in loss estimate (in months)	6 months
First Lien [Member] | Least Stressful Environment [Member] | RMBS [Member] | United States [Member] | Option ARM [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	(26,000,000)
First Lien [Member] | Least Stressful Environment [Member] | RMBS [Member] | United States [Member] | Subprime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	(47,000,000)
First Lien [Member] | Least Stressful Environment [Member] | RMBS [Member] | United States [Member] | Prime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	(500,000)
First Lien [Member] | Least Stressful Environment [Member] | RMBS [Member] | United States [Member] | Alt-A [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, increase (decrease) in expected loss to be paid, net	(26,000,000)
First Lien [Member] | Bank of America [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Collateral losses	4,200,000,000
First Lien [Member] | Bank of America [Member] | Base Scenario [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Collateral losses	5,200,000,000
First Lien [Member] | UBS [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Agreed reimbursement of R&W, percentage												85.00%
Assets held under trust for reimbursement payment	95,000,000
First Lien [Member] | BIG [Member] | RMBS [Member] | United States [Member] | Option ARM [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	170,000,000				183,000,000
First Lien [Member] | BIG [Member] | RMBS [Member] | United States [Member] | Subprime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	1,539,000,000				1,575,000,000
First Lien [Member] | BIG [Member] | RMBS [Member] | United States [Member] | Prime [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	349,000,000				353,000,000
First Lien [Member] | BIG [Member] | RMBS [Member] | United States [Member] | Alt-A [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	1,778,000,000				1,841,000,000
Second Lien [Member] | Closed-end [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR	15.00%
Second Lien [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Period from plateau to intermediate conditional default rate (in months)	28 months
Period of loan default estimate	5 months
Number of preceding months average liquidation rates used to estimate loan default rate	12 months
Number of months CDR is calculated by applying liquidation rates to past due balances	4 months
Stress period (in months)	34 months
Number of months of delinquent data	5 months
Period of constant conditional default rate (in months)	1 month
Conditional prepayment rate base case, average number of quarters	3 months
Number of conditional default rate curves modeled in estimating losses	3
Estimated benefit from loan repurchases related to breaches of R&W included in net expected loss estimates	83,000,000	[4]	151,000,000	[4]	85,000,000			143,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	1,000,000	[1]	(113,000,000)	[1]	(11,000,000)	[1]		(127,000,000)	[1]
Economic loss development after recoveries for R&W	(6,000,000)		(7,000,000)
Second Lien [Member] | RMBS [Member] | United States [Member] | HELOCs [Member]
Schedule of Expected Losses to be Paid [Line Items]
Estimated benefit from loan repurchases related to breaches of R&W included in net expected loss estimates	0	[4]	56,000,000	[4]	0			45,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	(10,000,000)	[1]	(109,000,000)	[1]	(19,000,000)	[1]		(116,000,000)	[1]
Economic loss development after recoveries for R&W	(5,000,000)		(2,000,000)
Net par amount outstanding	1,654,000,000				1,738,000,000
Second Lien [Member] | RMBS [Member] | United States [Member] | Closed-end [Member]
Schedule of Expected Losses to be Paid [Line Items]
Estimated benefit from loan repurchases related to breaches of R&W included in net expected loss estimates	83,000,000	[4]	95,000,000	[4]	85,000,000			98,000,000
Liability for unpaid claims and claims adjustment expense, net largest single loss	11,000,000	[1]	(4,000,000)	[1]	8,000,000	[1]		(11,000,000)	[1]
Economic loss development after recoveries for R&W	(1,000,000)		(5,000,000)
Net par amount outstanding	212,000,000				218,000,000
Second Lien [Member] | RMBS [Member] | United States [Member] | Home Equity Line of Credit and Closed-end Mortgage [Member]
Schedule of Expected Losses to be Paid [Line Items]
Final CPR	15.00%
Second Lien [Member] | HELOCs [Member]
Schedule of Expected Losses to be Paid [Line Items]
Loss recovery assumption (as a percent)					10.00%
Second Lien [Member] | Base Scenario [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Period from plateau to intermediate conditional default rate (in months)	28 months
Stress period (in months)	34 months
Period of constant conditional default rate (in months)	1 month
Second Lien [Member] | Base Scenario One [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Projected loss assumptions, CDR, plateau rate, projection period	4 months
Period from plateau to intermediate conditional default rate (in months)	33 months
Stress period (in months)	42 months
Increase in conditional default rate ramp down period	5 months
Second Lien [Member] | Base Scenario One [Member] | RMBS [Member] | United States [Member] | HELOCs [Member]
Schedule of Expected Losses to be Paid [Line Items]
Change in estimate for increased conditional default rate plateau period	14,000,000
Second Lien [Member] | Base Scenario One [Member] | RMBS [Member] | United States [Member] | Closed-end [Member]
Schedule of Expected Losses to be Paid [Line Items]
Change in estimate for decreased conditional default rate ramp down period	1,000,000
Second Lien [Member] | Based Scenario Two [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Stress period (in months)	24 months
Period of constant conditional default rate (in months)	1 month
Decreased conditional default rate ramp down period	18 months
Second Lien [Member] | Based Scenario Two [Member] | RMBS [Member] | United States [Member] | HELOCs [Member]
Schedule of Expected Losses to be Paid [Line Items]
Change in estimate for decreased conditional default rate ramp down period	14,000,000
Second Lien [Member] | Based Scenario Two [Member] | RMBS [Member] | United States [Member] | Closed-end [Member]
Schedule of Expected Losses to be Paid [Line Items]
Change in estimate for decreased conditional default rate ramp down period	1,000,000
Second Lien [Member] | Bank of America [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Agreed reimbursement of R&W, percentage													80.00%
Maximum loss up to which loss sharing percentage applicable													6,600,000,000
Second Lien [Member] | Bank of America [Member] | Base Scenario [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Assets held under trust for reimbursement payment	569,000,000
Second Lien [Member] | Guarantor Obligations, Group One [Member] | Deutsche Bank [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Maximum aggregate collateral losses up to which first layer of loss sharing will be applicable	319,000,000													319,000,000
Loss sharing percentage, first layer														80.00%
Second Lien [Member] | Guarantor Obligations, Group Two [Member] | Deutsche Bank [Member] | RMBS [Member] | United States [Member]
Schedule of Expected Losses to be Paid [Line Items]
Maximum aggregate collateral losses up to which first layer of loss sharing will be applicable														389,000,000
Loss sharing percentage, first layer														85.00%
Second Lien [Member] | Guarantor Obligations, Group Two [Member] | Deutsche Bank [Member] | RMBS [Member] | United States [Member] | Maximum [Member]
Schedule of Expected Losses to be Paid [Line Items]
Maximum aggregate collateral losses up to which first layer of loss sharing will be applicable														600,000,000
Second Lien [Member] | BIG [Member] | RMBS [Member] | United States [Member] | HELOCs [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	1,504,000,000				1,557,000,000
Second Lien [Member] | BIG [Member] | RMBS [Member] | United States [Member] | Closed-end [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	132,000,000				134,000,000
Other Assets [Member]
Schedule of Expected Losses to be Paid [Line Items]
Office building, carrying value	30,000,000
Southern District of Mississippi Vs Madison County, Mississippi [Member] | Radian [Member] | Public Finance [Member]
Schedule of Expected Losses to be Paid [Line Items]
Net par amount outstanding	$ 21,800,000

[1] Includes expected LAE to be paid of $13 million as of March 31, 2015 and $16 million as of December 31, 2014.

[2] Excludes $1.3 billion of loss mitigation securities insured and held by the Company as of March 31, 2015, which are primarily in the BIG category.

[3] Excludes $1.3 billion of loss mitigation securities insured and held by the Company as of December 31, 2014, which are primarily in the BIG category.

[4] See the section "Breaches of Representations and Warranties" below for eligible assets held in trust.

[5] For transactions where the initial CPR is higher than the final CPR, the initial CPR is held constant and the final CPR is not used.

[6] Represents variables for most heavily weighted scenario (the “base case”).

[7] Refer to Note 8, Financial Guaranty Contracts Accounted for as Credit Derivatives.