Investments (Details 6) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	$ 34	$ 23
Realized — impairments	(52)	(4)
Realized gains (losses) on securities	(18)	19
Fixed maturities [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	14	3
Realized — impairments	(16)	(5)
Realized gains (losses) on securities	(2)	(2)
Change in unrealized	453	218
Equity securities [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	23	21
Realized — impairments	(41)	(2)
Realized gains (losses) on securities	(18)	19
Change in unrealized	(23)	6
Other [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(3)	(1)
Realized — impairments	5	3
Realized gains (losses) on securities	2	2
Change in unrealized	(220)	(137)
Total Pretax [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	34	23
Realized — impairments	(52)	(4)
Realized gains (losses) on securities	(18)	19
Change in unrealized	210	87
Tax Effects [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	(12)	(8)
Realized — impairments	19	1
Realized gains (losses) on securities	7	(7)
Change in unrealized	(74)	(30)
Noncontrolling Interests [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	0	0
Realized — impairments	1	0
Realized gains (losses) on securities	1	0
Change in unrealized	(2)	(1)
Marketable Securities [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	22	15
Realized — impairments	(32)	(3)
Realized gains (losses) on securities	(10)	12
Change in unrealized	$ 134	$ 56

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Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments.

+ References

No definition available.

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This item represents the total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(c))
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27405-111563

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The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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