Commitments, Guarantees and Contingent Liabilities (Details 2) (USD $)	12 Months Ended		12 Months Ended						12 Months Ended		1 Months Ended	12 Months Ended				12 Months Ended
	Dec. 31, 2013 FL Citizens	Dec. 31, 2013 LA Citizens	Dec. 31, 2013 Florida Hurricane Catastrophe Fund	Dec. 31, 2010 Florida Hurricane Catastrophe Fund	Dec. 31, 2008 Florida Hurricane Catastrophe Fund	Dec. 31, 2013 California Earthquake Authority	Sep. 30, 2013 California Earthquake Authority	Dec. 31, 2012 California Earthquake Authority	Dec. 31, 2013 Guaranty Funds	Dec. 31, 2012 Guaranty Funds	Oct. 31, 2011 PMI runoff support agreement	Dec. 31, 2013 Texas Windstorm Insurance Association	Dec. 31, 2013 New Jersey Unsatisfied Claim and Judgment Fund	Dec. 31, 2013 North Carolina Reinsurance Facility	Dec. 31, 2013 North Carolina Joint Underwriters Association	Dec. 31, 2013 North Carolina Insurance Underwriting Association
Loss Contingencies
Assessment rate, percent of deficit or prior year premiums	2.00%	10.00%
Surcharge on policies, deadline for filing prior to imposing	15 days
Maximum emergency assessment as percent of premiums, first year			6.00%
Maximum emergency assessment as percent of premiums, second and subsequent years			10.00%
Catastrophe fund, bonds issued			$ 2,000,000,000	$ 676,000,000	$ 625,000,000
Emergency assessment ordered as percent of premiums from January 1, 2007 through December 31, 2010			1.00%
Emergency assessment ordered as percent of premiums after January 1, 2011			1.30%
CEA capital balance							4,430,000,000
CEA existing reinsurance layer							3,120,000,000
Current estimated maximum CEA assessment							1,660,000,000
CEA capital balance threshold							350,000,000
Estimated maximum second CEA assessment							385,000,000
CEA threshold earthquake losses							9,900,000,000
CEA capital balance to be restored							350,000,000
Projected aggregate claim paying capacity							9,900,000,000
Share of the CEA (as a percent)								14.80%
Maximum possible assessment						303,000,000						800,000,000				1,000,000,000
Issuance of securities to participating insurers upon utilization of funds set aside												1,000,000,000
Percentage of securities to be repaid by participating insurers' assessments												30.00%
Percentage of securities to be repaid by surcharges on coastal property policies												70.00%
Additional securities to be issued to participating insurers												500,000,000
Participation ratio												13.00%
Minimum medical benefits portion of personal injury protection coverage for reimbursement to insurers for policies issued or renewed prior to January 1, 1991													75,000
Minimum medical benefits portion of personal injury protection coverage for reimbursement to insurers for policies issued or renewed from January 1, 1991 to December 31, 2004													75,000
Maximum reimbursement to insurers for medical benefits paid under personal injury protection coverage.													250,000
Liability for insurance assessments									36,000,000	49,000,000			9,000,000
Fund's surplus to cover future losses														53,000,000
Plan surplus receivable															2,000,000
Percentage of surcharge on property insurance policy statewide to be remitted to the plan																10.00%
Insurance assessments, premium tax offsets									$ 31,000,000	$ 32,000,000
Percentage of claim payments to be made											50.00%