Contingencies, Commitments and Guarantees (details) (USD $)	6 Months Ended
	Jun. 30, 2011 years count	Dec. 31, 2010
Contingencies, Commitments and Guarantees disclosure
Number of purported class action suits filed against TPC and other insurers in state court in West Virginia relative to asbestos direct action litigation	2
Maximum lump-sum payment included in the settlement reached in November 2003 relative to Statutory and Hawaii Actions	$ 412,000,000
Maximum payment required under May 2004 settlement resolving substantially all pending and similar future Common Law Claims relative to Statutory and Hawaii Actions	90,000,000
Number of putative class action lawsuits brought against a number of insurers relative to broker anti-trust litigation	4
Amount Company has agreed to pay under broker anti-trust litigation settlement	6,750,000
Gain contingency	On August 20, 2010, in a reinsurance dispute in New York state court captioned United States Fidelity & Guaranty Company v. American Re-Insurance Company, et al., the trial court granted summary judgment for the Company, and on October 25, 2010, entered judgment awarding the Company $251 million plus pre-judgment interest in the amount of $169 million. United States Fidelity and Guaranty Company is a subsidiary of the Company. The $251 million awarded by the court represents the amount owed to the Company under the terms of the reinsurance agreements and is reported as part of reinsurance recoverables in the Company's consolidated balance sheet. The interest awarded by the Court is treated for accounting purposes as a gain contingency in accordance with FASB Topic 450, Contingencies, and accordingly has not been recognized in the Company's consolidated financial statements. Post-judgment interest continues to accrue at the rate of 9 percent (without compounding) on the total judgment of $420 million. The judgment, including the award of interest, was appealed to the New York Supreme Court, Appellate Division, First Department, and oral argument occurred on May 10, 2011. The parties await a ruling from the Appellate Division.
Unfunded commitments to private equity limited partnerships and real estate partnerships	$ 1,240,000,000	$ 1,260,000,000
Term of indemnification provisions arising from sales of business entities	In the ordinary course of selling business entities to third parties, the Company has agreed to indemnify purchasers for losses arising out of breaches of representations and warranties with respect to the business entities being sold, covenants and obligations of the Company and/or its subsidiaries following the closing, and in certain cases obligations arising from undisclosed liabilities, adverse reserve development, imposition of additional taxes due to either a change in the tax law or an adverse interpretation of the tax law, or certain named litigation. Such indemnification provisions generally survive for periods ranging from two years following the applicable closing date to the expiration of the relevant statutes of limitations, although, in some cases, there may be other agreed upon term limitations or no term limitations.