Litigation and Contingencies (Details) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended					36 Months Ended
	Mar. 31, 2014	Jun. 30, 2009	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011
Curtailments [Abstract]
Average paid claim reduction due to curtailments (in hundredths)	5.90%		5.80%
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	$ 26,000,000		$ 135,000,000	$ 300,000,000				$ 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%
Mitigation of incurred losses by rescission of policies	0		0	0	0	200,000,000	2,500,000,000
Reduction in estimated rescissions				200,000,000
Total loss reserves, estimated benefit from rescissions	70,000,000
Rescissions dispute period not ended (in hundredths)	26.00%
Statute of limitations to bring legal proceedings disputing right to rescind coverage	3 years
Maximum exposure above estimate provision	484,000,000
Exposure from rescission practices (in hundredths)	50.00%
Maximum exposure associated with other discussions and legal proceedings	266,000,000
Class action complaint under RESPA [Abstract]
Period of existing captive reinsurance agreement	10 years
Civil penalty			2,650,000
Other Legal Proceedings [Abstract]
Underwriting remedy expense	2,000,000		5,000,000
Class Action Complaint Under RESPA [Member] | Pending Litigation [Member]
Class action complaint under RESPA [Abstract]
Number of lawsuits	12
Number of cases dismissed	7
Countrywide Dispute [Member] | Pending Litigation [Member]
Claims resolved by rescissions [Abstract]
Amount of damages sought	$ 700,000,000
Lawsuits alleging improper recording and foreclosure activities by MERS [Member] | Pending Litigation [Member]
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