Litigation and contingencies (Details) (USD $)				3 Months Ended				3 Months Ended		12 Months Ended
	Mar. 31, 2012	Apr. 19, 2012 Class Action Complaint Under RESPA [Member] Pending Litigation [Member]	Mar. 31, 2012 Class Action Complaint Under RESPA [Member] Pending Litigation [Member] U.S. District Court for the Central District of California [Member]	Mar. 31, 2012 Housing discrimination complaint [Member] Pending Litigation [Member] U.S. District Court for the Western District of Pennsylvania [Member]	Dec. 31, 2011 Housing discrimination complaint [Member] Pending Litigation [Member] U.S. District Court for the Western District of Pennsylvania [Member]	Mar. 31, 2012 Class action lawsuit alleging discrimination [Member] Pending Litigation [Member] U.S. District Court for the Western District of Pennsylvania [Member]	Mar. 31, 2012 Class action complaint alleging violations of securities laws [Member] Pending Litigation [Member] U.S. District Court for the Eastern District of Wisconsin [Member]	Mar. 31, 2012 Countrywide Dispute [Member] Pending Litigation [Member]	Mar. 31, 2012 Freddie Mac's disagreement on aggregate loss limit [Member]	Dec. 31, 2011 Freddie Mac's disagreement on aggregate loss limit [Member]	Mar. 31, 2012 Lawsuits alleging improper recording and foreclosure activities by MERS [Member] Pending Litigation [Member]
Class action complaint under RESPA [Abstract]
Mortgage insurers named as defendants in class action			7
Number of similar cases filed naming various mortgage lenders and mortgage insurers as defendants		6
Number of cases dismissed voluntarily		1									1
Number of cases alleging violation of RESPA		7
Housing discrimination complaint - U.S. Department of Justice ("DOJ") [Abstract]
Number of employees named in the complaint					2
Settlement agreement date				2012-04-30
Settlement amount				$ 511,250		$ 500,000
Number of individuals covered by settlement				70
Loss Contingency, Settlement Agreement, Civil Penalty				38,750
Incentive fee						7,500
Class action complaints - Fulton County Employees' Retirement System [Abstract]
Number of previously filed purported class action complaints							5
Number of officers of C-BASS named as defendants in complaint							2
Number of officers named as defendants in amended complaint							2
Number of officers of C-BASS named as defendants in amended complaint							2
Countrywide dispute [Abstract]
Mitigation of paid losses								435,000,000
Average claims payment had the loans not been rescinded (per loan)								72,300
Amount of damages sought								700,000,000
Number of loans that each of the plaintiff and the defendant have selected								12
Number of members on arbitration panel								3
Total number of loans selected by both plaintiff and defendant combined								24
Number of rescindable loans affected by Company's decision to suspend rescissions	860							860
Total potential claim payments of rescindable loans affected by Company's decision to suspend rescissions	65,000,000							65,000,000
Number of loans in primary delinquency inventory related to plaintiff								34,825
Percentage of loans in primary delinquency inventory related to plaintiff (in hundredths)								22.00%
Claims paid (in hundredths)								80.00%
Claims rescinded (in hundredths)								20.00%
Claims paid had the Company processed the rescissions it has suspended								78.00%
Claims rescinded had the Company processed the rescissions it has suspended								22.00%
Mitigation of incurred losses since January 2008								3,100,000,000
Mitigation on paid losses, excluding deductible amounts								2,700,000,000
Amount excluded from mitigation on paid losses that would have been applied to a deductible								600,000,000
Total loss reserves, estimated benefit from rescissions								600,000,000
Freddie Mac dispute [Abstract]
Difference in aggregate loss limit under pool insurance policy									535,000,000
Impact of aggregate loss limit difference under pool insurance policy on results of operations									$ 49,000,000	$ 192,000,000
Lawsuits alleging improper recording and foreclosure activities by MERS [Abstract]
Number of lawsuits naming non-insurance subsidiary as defendant											4
Number of cases dismissed		1									1
Number of other lawsuits naming subsidiary as defendant that were dismissed											2