Segments Information (Details 1) (USD $) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Income (loss) before income tax [Abstract]
Total property and casualty insurance	$ 540	$ 652	$ 1,128	$ 1,236
Corporate and other loss	(63)	(40)	(126)	(103)
Realized investment gains, Net	69	90	229	217
Income Before Federal and Foreign Income Tax	546	702	1,231	1,350
Property and casualty insurance [Member]
Income (loss) before income tax [Abstract]
Underwriting income related to insurance business	93	241	265	410
Reinsurance assumed underwriting income	10	1	15	14
Statutory underwriting income	103	242	280	424
Increase in deferred policy acquisition costs	32	21	57	43
Underwriting income	135	263	337	467
Investment income	394	385	775	772
Other income (charges)	11	4	16	(3)
Property and casualty insurance [Member] \| Personal insurance [Member]
Income (loss) before income tax [Abstract]
Underwriting income related to insurance business	3	42	84	18
Property and casualty insurance [Member] \| Commercial insurance [Member]
Income (loss) before income tax [Abstract]
Underwriting income related to insurance business	(54)	68	(98)	111
Property and casualty insurance [Member] \| Specialty insurance [Member]
Income (loss) before income tax [Abstract]
Underwriting income related to insurance business	$ 144	$ 131	$ 279	$ 281

Represents income (loss) before income tax related to non-insurance companies before realized investment gain (loss).

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- Details

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- Definition

Amount of underwriting income (loss) for the reportable property and casualty insurance segments which is arrived at by reducing premiums earned by losses and loss expenses incurred and statutory underwriting expenses incurred, before reinsurance assumed business which is in run-off. Under statutory accounting principles, policy acquisition and other underwriting expenses are recognized immediately, not at the time premiums are earned.

+ Details

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- Definition

Reflects the sum of all other income and charges recognized by the entity in the period not otherwise specified separately.

+ Details

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- Definition

Amount of income (loss) before income tax for property and casualty insurance including underwriting income (loss), investment income (loss) and other income (charges), before realized investment gain (loss).

+ Details

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- Definition

Amount of underwriting income (loss) for the property and casualty insurance reinsurance assumed segment, which is in run-off, which is arrived at by reducing premiums earned by losses and loss expenses incurred and statutory underwriting expenses incurred. Under statutory accounting principles, policy acquisition and other underwriting expenses are recognized immediately, not at the time premiums are earned.

+ Details

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- Definition

Amount of underwriting income (loss) for the property and casualty insurance segments which is arrived at by reducing premiums earned by losses and loss expenses incurred and statutory underwriting expenses incurred. Under statutory accounting principles, policy acquisition and other underwriting expenses are recognized immediately, not at the time premiums are earned.

+ Details

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- Definition

Amount of underwriting income (loss) for the property and casualty insurance segments which is arrived at by reducing premiums earned by losses and loss expenses incurred and generally accepted accounting principles (GAAP) underwriting expenses incurred. Under GAAP, policy acquisition expenses are deferred and amortized over the period in which the related premiums are earned.

+ Details

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- Definition

This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain or loss of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain or loss which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains or losses realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments of the subject investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 7
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13, 22

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- Definition

Sum of operating profit and nonoperating income (expense) before income (loss) from equity method investments, income taxes, extraordinary items, cumulative effects of changes in accounting principles, and noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Subparagraph 1(i)
-Article 4

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- Definition

The net change during the reporting period in the balance sheet value of capitalized sales costs that are associated with acquiring a new insurance customers.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28

+ Details

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- Definition

The total amount of investment earnings, excluding realized and unrealized gain (loss), recognized in the period on the entity's investments, net of related investment expenses. Such amount includes interest, dividends, and rental income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 2
-Article 7

+ Details

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