Income Taxes (Unrecognized Tax Benefits Reconciliation) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 39us-gaap_UnrecognizedTaxBenefits	$ 30us-gaap_UnrecognizedTaxBenefits	$ 28us-gaap_UnrecognizedTaxBenefits
Additions based on tax positions related to the current period	7	7	5
Additions based on tax positions of prior years	3	1	3
Reductions based on tax positions of prior years	(1)	0	0
Settlements	(3)	0	(5)
Foreign exchange	(8)	1	(1)
Ending Balance	$ 37us-gaap_UnrecognizedTaxBenefits	$ 39us-gaap_UnrecognizedTaxBenefits	$ 30us-gaap_UnrecognizedTaxBenefits

Unrecognized Tax Benefits, Net Changes Resulting from Foreign Currency Translation

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- Definition

Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15A

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

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-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

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-Paragraph 15A

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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