Commitments and Contingencies (Details) (USD $)	3 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended		1 Months Ended		12 Months Ended	1 Months Ended				0 Months Ended		1 Months Ended
	Sep. 30, 2013 Lawsuit	Dec. 31, 2008 Proceedings related to former financial products business Lawsuit	Jul. 31, 2010 AGMH Person	Sep. 30, 2009 AGMH Proceedings related to former financial products business Plaintiff	Dec. 31, 2008 AGMH Proceedings related to former financial products business Lawsuit	Dec. 31, 2008 AGM and AGMH Proceedings related to former financial products business Lawsuit	May 31, 2010 AGM and AGUS Proceedings related to former financial products business Lawsuit	Apr. 30, 2010 AGM and AGUS Proceedings related to former financial products business Lawsuit	Dec. 31, 2009 AGM and AGUS Proceedings related to former financial products business Lawsuit	Mar. 31, 2010 AGRe and AGCV's Ambac [Member] AG Re and AGC Guarantee obligations commutation	Nov. 28, 2011 LBIE vs. AG Financial Products [Member] AG Financial Products Inc. Guarantee obligations Transaction	Nov. 19, 2012 LBHI and LBSF vs CPT 283, FSA and AGM [Member] AGM	Nov. 19, 2012 LBHI and LBSF vs CPT 207, FSA and AGM [Member] AGM	Oct. 24, 2013 Subsequent Event [Member] AGRe and AGCV's Ambac [Member] AG Re and AGC Guarantee obligations	Sep. 25, 2013 Pending Litigation [Member] Wells Fargo Bank, N.A., Interpleader Complaint [Member] AGM	Oct. 31, 2013 Pending Litigation [Member] Subsequent Event [Member] Charles E. Wilson vs. JPMorgan Chase & Co et al [Member] AGM
Commitments and Contingencies Legal Proceedings
Minimum Number of Proceedings for Recoveries to Have Potential Material Impact	1
Litigation Case, Voting Class, Aggregate Claims Amount, Accept Vote																$ 3,900,000,000
Litigation Case, Voting Class, Aggregate Claims Amount, Reject Vote																18,000,000
Percentage of amount in segregated account payable in cash										25.00%
Percentage of amount in segregated account payable in surplus notes issued										75.00%
Number of commutations disputed										1
Loss of recovery														200,000
Number of credit derivative transactions for which termination payment is alleged to be improperly calculated											9
Number of credit derivative transactions alleged to be improperly terminated											28
Termination payments which LBIE owes to AG Financial Products as per calculation of AG Financial Products											25,000,000
Termination payments which AG Financial Products owes to LBIE as per calculation of LBIE											1,400,000,000
Termination payments which LBSF owes to CPT 283 and AG Financial Products as per calculation of AG Financial Products												43,800,000
Termination payments which AG Financial Products and CPT 283 owes to LBHI and LBSF as per calculation of LBHI and LBSF												67,300,000
Termination payments which LBSF owes to CPT 207 and AG Financial Products as per calculation of AG Financial Products													492,555
Termination payments which AG Financial Products and CPT 207 owes to LBHI and LBSF as per calculation of LBHI and LBSF													1,500,000
Loss Contingency Accrual, Period Increase (Decrease)															$ 10,000,000
Number of persons indicted who worked at Financial Guaranty Insurance Company			2
Number of persons convicted of conspiracy and fraud who worked at Financial Guaranty Insurance Company			2
Number of putative class action lawsuits filed in federal court		9			4	5
Number of plaintiffs filing consolidated complaints				4
Number of non-class action lawsuits filed						5	5		6
Number of non-class action lawsuits for which dismissal was denied								11