Guarantees and Contingent Liabilities (Details) (USD $)	6 Months Ended
Jun. 30, 2011	Dec. 31, 2010
Proceedings:
Loss contingencies, reasonably possible pretax loss exposure in excess of the amount accrued, low estimate	$ 0
Loss contingencies, reasonably possible pretax loss exposure in excess of the amount accrued, high estimate	855,000,000
Accrued settlement due to prior year reserve reestimate in property-liability insurance claims and claims expense		75,000,000
Number of former employee agents plaintiffs seek benefits for	6,500
Reserves for asbestos claims	1,090,000,000	1,100,000,000
Reinsurance recoverables for asbestos claims	529,000,000	555,000,000
Reserves for environmental claims	192,000,000	201,000,000
Reinsurance recoverables for environmental claims	44,000,000	47,000,000
Percentage of net asbestos and environmental reserves that were for incurred but not reported estimated losses (as a percent)	61.00%	60.00%
Guarantee on fixed income securities
Guarantees:
Maximum amount at risk pursuant to a guarantee	67,000,000
Residual guarantee
Guarantees:
Maximum amount at risk pursuant to a guarantee	$ 8,000,000
Guarantee obligation term	Less than one year to three years

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Carrying amount as of the balance sheet date of reserves for the costs of settling insured claims and costs incurred in the claims settlement process attributable to asbestos, net of estimated reinsurance recoveries.

+ Details

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- Definition

Carrying amount as of the balance sheet date of reserves for the costs of settling insured claims and costs incurred in the claims settlement process attributable to environmental claims, net of estimated reinsurance recoveries.

+ Details

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- Definition

Represents the amount accrued for loss contingency settlement.

+ Details

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- Definition

Represents the amount of former employee agents plaintiffs seek benefits for.

+ Details

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- Definition

The percentage of net asbestos and environment reserves that were for incurred but not reported estimated losses.

+ Details

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- Definition

The known and estimated amount recoverable related to asbestos claims as of the balance sheet date from reinsurers for claims paid or incurred by the ceding insurer and associated claims settlement expenses, including estimated amounts for claims incurred but not reported, and policy benefits, net of any related valuation allowance.

+ Details

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- Definition

The known and estimated amount recoverable related to environment related claims as of the balance sheet date from reinsurers for claims paid or incurred by the ceding insurer and associated claims settlement expenses, including estimated amounts for claims incurred but not reported, and policy benefits, net of any related valuation allowance.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph b

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- Definition

Describe the approximate term of the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 45
-Paragraph 13
-Subparagraph a

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- Definition

The estimated maximum amount of possible loss from the contingency.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12

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The estimated minimum amount of possible loss from the contingency.

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