Components of Net Postemployment Costs (Detail) (Postemployment Benefit Plans, USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9us-gaap_DefinedBenefitPlanServiceCost	$ 8us-gaap_DefinedBenefitPlanServiceCost	$ 12us-gaap_DefinedBenefitPlanServiceCost
Interest cost	6us-gaap_DefinedBenefitPlanInterestCost	5us-gaap_DefinedBenefitPlanInterestCost	8us-gaap_DefinedBenefitPlanInterestCost
Amortization of net (gains) / losses		(1)	(3)
Other		(1)us-gaap_DefinedBenefitPlanOtherCosts	3us-gaap_DefinedBenefitPlanOtherCosts
Net postemployment costs	15	11	15
Segment, Discontinued Operations
Defined Benefit Plan Disclosure [Line Items]
Net postemployment costs			$ (5)

The amount of gains or losses recognized in net periodic benefit cost.

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- Details

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- Definition

The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

+ References

+ Details

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- Definition

The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

+ References

+ Details

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- Definition

Amount of other defined benefit plan costs.

+ References

No definition available.

+ Details

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- Definition

The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (h)(1)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Service Cost (Component of Net Periodic Pension Cost)

-URI http://asc.fasb.org/extlink&oid=6525008

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

+ Details

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