Investments (Details Textuals 2) (USD $)	Sep. 30, 2011	Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]
Amortized cost of the sovereign fixed maturity securities	$ 259,186,000,000	$ 238,214,000,000
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Equity securities holdings exposure in single issuer greater than stated percentage of Company's equity	10.00%	10.00%
Equity securities holdings exposure amount of a single issuer greater than 10% of Company's equity	0	0
Fixed maturity securities exposure to single issuer greater than a stated percentage of stockholders' equity	10.00%	10.00%
Fixed maturity securities exposure to single issuer less than a stated percentage of stockholders' equity	10.00%	10.00%
Fixed maturity securities exposure amount to single issuer greater than 10% of the Company's stockholders' equity other than the U.S. and Mexican government securities	0	0
Holdings in European sovereign fixed maturity securities at estimated fair value	629,000,000	1,562,000,000
Net exposure in holdings in European sovereign fixed maturity securities stated percentage of the Company's equity	1.00%	3.20%
Net exposure in holdings in European sovereign fixed maturity securities stated percentage of total cash and invested assets	0.10%	0.30%
European Sovereign Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost of the sovereign fixed maturity securities	571,000,000	1,644,000,000
Par Value of the sovereign fixed maturity securities	1,018,000,000	1,912,000,000
Mexico [Member] \| US Government Agencies Debt Securities [Member]
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Fair Value Concentration Of Risk Investments Less Than Ten Percent	$ 5,028,000,000

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading at Par Value.

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Investment disclosure of credit risk exposure amount to fixed maturity securities in single issuer other than securities of the U.S. government, certain U.S. government agencies and certain securities guaranteed by the U.S. government, as well as securities of the Mexican government and certain Mexican government agencies greater than a stated percentage of Company's stockholders' equity.

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Investment disclosure of credit risk exposure to fixed maturity securities in single issuer greater than a stated percentage of Company's stockholders' equity.

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Investment disclosure of credit risk exposure to fixed maturity securities in single issuer lesser than a stated percentage of Company's stockholders' equity.

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Investment disclosure of credit risk exposure to equity securities holdings greater than a stated percentage of the Company's stockholders' equity.

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Investment disclosure of holdings in sovereign fixed maturity securities of Portugal, Ireland, Italy, Greece and Spain, commonly referred to as Europe's perimeter region, stated at estimated fair value.

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This item represents disclosure of all significant concentrations of credit risk or market risk arising from the subject financial instrument (as defined), whether from an individual counterparty or groups of counterparties. This is not greater than 10% of the Company's Equity.

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Investment disclosure of Net exposure in holdings in sovereign fixed maturity securities of Portugal, Ireland, Italy, Greece and Spain, commonly referred to as Europe's perimeter region, stated percentage of total cash and invested assets.

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