Change in Unrealized Gains and Losses, Net of Taxes, Included in Other Comprehensive Income and Shareholders' Equity (Detail) (USD $) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Gain (Loss) on Investments [Line Items]
Adjustment to deferred acquisition costs and life policy reserves	$ (4)	$ (4)	$ (4)	$ (7)
Pension obligations	1		2	1
Income taxes on above	(26)	46	(72)	(6)
Total	48	(86)	134	12
Debt Securities
Gain (Loss) on Investments [Line Items]
Available for sale	96	123	104	209
Equity Securities
Gain (Loss) on Investments [Line Items]
Available for sale	(21)	(254)	101	(190)
Other Investments
Gain (Loss) on Investments [Line Items]
Other	$ 2	$ 3	$ 3	$ 5

This element represents Other Comprehensive Income or Loss, Net of Tax, for the period. Includes deferred gains or losses on qualifying hedges, unrealized holding gains or losses on available-for-sale securities, minimum pension liability, and cumulative translation adjustment. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label.

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-Name Statement of Financial Accounting Standard (FAS)
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Research Bulletin (ARB)
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+ Details

- Definition

Tax effect of the change in accumulated other comprehensive income (loss), that is, the tax effect on items included in other comprehensive income (loss) during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Number 109
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+ Details

- Definition

The pretax amount of the change in the additional minimum pension liability not yet recognized pursuant to FAS 87 as a net periodic pension cost. If the additional pension liability required to be recognized exceeds the unrecognized prior service costs, then the excess (which is the net loss not yet recognized as net periodic pension cost) is to be recorded as a separate component in other comprehensive income, before adjusting for tax effects. In a subsequent measurement, the elimination or adjustment to the amount of the minimum pension liability recorded in accumulated other comprehensive income is included in this line. Eliminated upon adoption of FAS 158.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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+ Details

- Definition

Gross appreciation or the gross loss in value of the total of unsold available-for-sale securities during the period being reported (except when designated as a fair value hedge).

+ References

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+ Details