Pension Benefits - Schedule Of Reconciliation Of Level 3 Plan Assets Held (Details) - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2016	Mar. 31, 2015
U.S. Plans
Change in plan assets
Fair value of plan assets at beginning of period	$ 298	$ 300
Fair value of plan assets at end of period	262	298
U.S. Plans \| Level 3
Change in plan assets
Fair value of plan assets at beginning of period	18	16
Acquisitions	0	0
Unrealized gain on plan assets still held	1	2
Purchases, sales and settlements	(2)	0
Fair value of plan assets at end of period	17	18
U.S. Plans \| Real Estate Funds
Change in plan assets
Fair value of plan assets at beginning of period	18
Fair value of plan assets at end of period	17	18
U.S. Plans \| Real Estate Funds \| Level 3
Change in plan assets
Fair value of plan assets at beginning of period	18	16
Acquisitions	0	0
Unrealized gain on plan assets still held	1	2
Purchases, sales and settlements	(2)	0
Fair value of plan assets at end of period	17	18
Non-U.S. Plans
Change in plan assets
Fair value of plan assets at beginning of period	612	590
Fair value of plan assets at end of period	607	612
Non-U.S. Plans \| Level 3
Change in plan assets
Fair value of plan assets at beginning of period	30	12
Acquisitions	0	0
Unrealized gain on plan assets still held	(3)	1
Purchases, sales and settlements	0	17
Fair value of plan assets at end of period	27	30
Non-U.S. Plans \| Real Estate Funds
Change in plan assets
Fair value of plan assets at beginning of period	26
Fair value of plan assets at end of period	24	26
Non-U.S. Plans \| Real Estate Funds \| Level 3
Change in plan assets
Fair value of plan assets at beginning of period	26	7
Acquisitions	0	0
Unrealized gain on plan assets still held	(2)	1
Purchases, sales and settlements	0	18
Fair value of plan assets at end of period	24	26
Non-U.S. Plans \| Other \| Level 3
Change in plan assets
Fair value of plan assets at beginning of period	4	5
Acquisitions	0	0
Unrealized gain on plan assets still held	(1)	0
Purchases, sales and settlements	0	(1)
Fair value of plan assets at end of period	$ 3	$ 4

Actual return on plan assets, separately identifying the amount related to assets still held at the reporting date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(02)(A)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(iv)(02)(A)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920

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- Definition

The amount of increase in the plan assets attributed to a business combination.

+ References

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
-Section 35
-Paragraph 50
-URI http://asc.fasb.org/extlink&oid=49178875&loc=d3e12355-114930

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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- Definition

Amount of increase (decrease) in plan assets from purchases, sales and settlement of plan obligations.

+ 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 (d)(iv)(02)(B)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)(iv)(02)(B)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920

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