Reinsurance - Life Insurance Contract Holders' Benefits Incurred on Ceded Business (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Insurance losses and contract holders' benefits	$ 670	$ 686	$ 2,131	$ 2,181
Life Insurance Segment
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct contract holders' benefits incurred	70	80	214	228
Ceded contract holders' benefits incurred	(13)	(16)	(39)	(52)
Insurance losses and contract holders' benefits	$ 57	$ 64	$ 175	$ 176

Amount, before effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred.

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- Definition

Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.5)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 20

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6480758&loc=d3e6811-158387

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 5

-Article 7

+ Details

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- Definition

Amount of reduction of provision for policy benefits and costs incurred for policies ceded.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 20

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6480758&loc=d3e6811-158387

+ 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.

+ References

No definition available.

+ Details

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