Loss Reserves (Details) (USD $)	3 Months Ended				12 Months Ended
	Mar. 31, 2014 Loan		Mar. 31, 2013 Loan		Dec. 31, 2012 Loan	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2013 Loan
Loss Reserve [Roll Forward]
Reserve at beginning of period	$ 3,061,401,000		$ 4,056,843,000
Less reinsurance recoverable	64,085,000		104,848,000
Net reserve at beginning of period	2,776,941,000	[1]	3,752,169,000	[1]	3,951,995,000			2,997,316,000
Losses and LAE incurred in respect of default notices related to:
Current year	155,982,000		268,793,000
Prior years	(33,374,000)	[2]	(2,585,000)	[2]
Subtotal	122,608,000		266,208,000
Losses and LAE paid in respect of default notices related to:
Current year	314,000		246,000
Prior years	342,669,000		468,933,000
Reinsurance terminations	0	[3]	(3,145,000)	[3]
Subtotal	342,983,000		466,034,000
Net reserve at beginning of period	2,776,941,000	[1]	3,752,169,000	[1]	3,951,995,000			2,997,316,000
Plus reinsurance recoverables	57,618,000		96,179,000		104,848,000
Reserve at end of period	2,834,559,000		3,848,348,000		4,056,843,000
Loss reserve reduction from rescission	70,000,000		200,000,000
Reduction in estimated rescissions					200,000,000
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves	(33,000,000)	[4]	(3,000,000)	[4]
Historical average period for uncured default to develop into paid claim	12 months
Premium refund liability, expected claim payments	126,000,000							131,000,000
Primary Default Inventory [Roll Forward]
Default inventory at the beginning of period	103,328		139,845
New Notices	23,346		27,864
Cures	(27,318)		(31,122)
Paids (including those charged to a deductible or captive)	(7,064)		(9,445)
Rescissions and denials	(450)		(532)
Default inventory at end of period	91,842		126,610		139,845
Pool insurance notice inventory [Abstract]
Pool insurance notice inventory (in number of loans)	5,646		7,890					6,563
Aging of the Primary Default Inventory [Abstract]
3 months or less	14,313		17,973					18,941
3 months or less (in hundredths)	16.00%		14.00%					18.00%
4 - 11 months	23,305		32,662					24,514
4 - 11 months (in hundredths)	25.00%		26.00%					24.00%
12 months or more	54,224		75,975					59,873
12 months or more (in hundredths)	59.00%		60.00%					58.00%
Total primary default inventory	91,842		126,610		139,845
Total primary default inventory (in hundredths)	100.00%		100.00%					100.00%
Primary claims received inventory included in ending default inventory	5,990	[5]	10,924	[5]				6,948	[5]
Primary claims received inventory included in ending default inventory (in hundredths)	7.00%	[5]	9.00%	[5]				7.00%	[5]
Number of payments delinquent [Abstract]
3 payments or less	23,035		28,376					28,095
3 payments or less (in hundredths)	25.00%		23.00%					27.00%
4 - 11 payments	22,766		32,253					24,605
4 - 11 payments (in hundredths)	25.00%		25.00%					24.00%
12 payments or more	46,041		65,981					50,628
12 payments or more (in hundredths)	50.00%		52.00%					49.00%
Total primary default inventory	91,842		126,610		139,845
Total primary default inventory (in hundredths)	100.00%		100.00%					100.00%
Estimated Rescission Reduction - Loss Reserve [Roll Forward]
Estimated rescission reduction - losses incurred						200,000,000	2,500,000,000
Premium refund liability, expected future rescissions	14,000,000							15,000,000
Countrywide Home Loans [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Number of rescindable loans affected by Company's decision to voluntarily suspend rescissions	1,525
Increase (Decrease) in Estimated Claim Rate On primary Defaults [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves	(30,000,000)	[4]	(15,000,000)	[4]
Percentage of prior year default inventory resolved (in hundredths)	25.00%		23.00%
Increase (Decrease) in Estimated Severity, Primary Defaults [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves	5,000,000	[4]	20,000,000	[4]
Change In Estimates Related to Pool Reserves, LAE Reserves and Reinsurance [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves	$ (8,000,000)	[4]	$ (8,000,000)	[4]

[1] At March 31, 2014 and 2013, the estimated reduction in loss reserves related to rescissions approximated $70 million and $0.2 billion, respectively.

[2] A negative number for prior year losses incurred indicates a redundancy of prior year loss reserves and a positive number for prior year losses incurred indicates a deficiency of prior year loss reserves.

[3] In a termination, the reinsurance agreement is cancelled, with no future premium ceded and funds for any incurred but unpaid losses transferred to us. The transferred funds result in an increase in our investment portfolio (including cash and cash equivalents) and a decrease in net losses paid (reduction to losses incurred). In addition, there is an offsetting decrease in the reinsurance recoverable (increase in losses incurred), and thus there is no net impact to losses incurred.

[4] A negative number for prior year loss development indicates a redundancy of prior year loss reserves, and a positive number indicates a deficiency of prior year loss reserves.

[5] Our claims received inventory includes suspended rescissions, as we have voluntarily suspended rescissions of coverage related to certain loans that we believed would be included in a potential resolution. As of March 31, 2014, rescissions of coverage on approximately 1,525 loans had been voluntarily suspended.