Litigation and Contingencies (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2009	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2013 Class Action Complaint Under RESPA [Member] Pending Litigation [Member] Case Lawsuit	Dec. 31, 2013 Countrywide Dispute [Member] Pending Litigation [Member]	Sep. 30, 2013 Bank of America, N.A. [Member] Pending Litigation [Member] Loan	Sep. 30, 2013 Lawsuits alleging improper recording and foreclosure activities by MERS [Member] Pending Litigation [Member] Loan
Class action complaint under RESPA [Abstract]
Civil penalty		$ 2,650,000
Period of existing captive reinsurance agreement		10 years
Number of lawsuits							12
Number of cases dismissed							7
Curtailments [Abstract]
Average paid claim reduction due to curtailments (in hundredths)		5.80%	4.10%	3.00%
Number of days after claim paid within which objection must be received for review		90 days
Claims resolved by rescissions [Abstract]
Mitigation of paid losses by rescission of policies		135,000,000	300,000,000	3,000,000,000	3,000,000,000	3,000,000,000
Percentage of claims received in a quarter resolved by rescission, lower range limit (in hundredths)		5.00%
Percentage of claims received in a quarter resolved by rescission, upper range limit (in hundredths)	28.00%
Statute of limitations to bring legal proceedings disputing right to rescind coverage		3 years
Mitigation of incurred losses by rescission of policies		0	0	0	200,000,000	2,500,000,000
Reduction in estimated rescissions			200,000,000
Loss reserve reduction from rescission		100,000,000	200,000,000	700,000,000	1,300,000,000
Rescissions dispute period not ended (in hundredths)		28.00%
Amount of damages sought								700,000,000
Number of rescindable loans affected by Company's decision to suspend rescissions for Countrywide									2,100
Maximum exposure above estimate provision		475,000,000
Exposure from rescission practices (in hundredths)		50.00%
Maximum exposure associated with other discussions and legal proceedings		260,000,000
Lawsuits alleging improper recording and foreclosure activities by MERS [Abstract]
Number of lawsuits naming non-insurance subsidiary as defendant										8
Number of lawsuits naming subsidiary as defendant that were dismissed										7
Other Legal Proceedings [Abstract]
Underwriting remedy expense		$ 5,000,000	$ 27,000,000	$ 23,000,000	$ 19,000,000