Consolidated Statements Of Shareholders' Equity (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net unrealized appreciation on investments, Change in year, income tax (expense) benefit	$ (167)	$ 408	$ (198)
Cumulative translation adjustment, Change in year, income tax(expense) benefit	(12)	63	(35)
Pension liability adjustment, Change in year, income tax (expense) benefit	4	0	12
Net unrealized appreciation on investments
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	33	(88)
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Net unrealized appreciation on investments
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	(176)	391
Reclassification from Accumulated Other Comprehensive Income, Current Period, Tax	$ 9	$ 17

Reclassification from Accumulated Other Comprehensive Income, Current Period, Tax

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Amount of tax expense (benefit), after reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 10A

-Subparagraph (e)

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Amount of tax expense (benefit), after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

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-Section 45

-Paragraph 10A

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Amount of tax (expense) benefit, after reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

+ References

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

+ References

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-Publisher FASB

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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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