Hedging Activities - Derivative Instruments Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2017	Mar. 31, 2017
Derivatives Designated for Hedge Accounting
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	$ 41	$ 156
Fair value of derivative, liability	163	0
Derivatives Designated for Hedge Accounting \| Foreign Exchange Contract \| Prepaid Expenses and Other
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	14	17
Fair value of derivative, liability	0	0
U.S. Dollar notional amount, asset	81	81
Derivatives Designated for Hedge Accounting \| Foreign Exchange Contract \| Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	27	32
Fair value of derivative, liability	0	0
U.S. Dollar notional amount, asset	162	162
Derivatives Designated for Hedge Accounting \| Cross Currency Swap \| Prepaid Expenses and Other
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	0	17
Fair value of derivative, liability	0	0
U.S. Dollar notional amount, asset	307	174
Derivatives Designated for Hedge Accounting \| Cross Currency Swap \| Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset		90
Fair value of derivative, liability		0
U.S. Dollar notional amount, asset		2,489
Derivatives Designated for Hedge Accounting \| Cross Currency Swap \| Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	0
Fair value of derivative, liability	163
U.S. Dollar notional amount, asset	3,104
Derivatives not Designated for Hedge Accounting
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	0	1
Fair value of derivative, liability	0	0
Derivatives not Designated for Hedge Accounting \| Foreign Exchange Contract \| Prepaid Expenses and Other
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	0	1
Fair value of derivative, liability	0	0
U.S. Dollar notional amount, asset	28	198
Derivatives not Designated for Hedge Accounting \| Foreign Exchange Contract \| Other Accrued Liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	0	0
Fair value of derivative, liability	0	0
U.S. Dollar, notional amount, liability	$ 6	$ 37

Nominal or face amount used to calculate payments on the derivative asset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5580258-113959

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226000-175313

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Nominal or face amount used to calculate payments on the derivative liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5580258-113959

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+ References

No definition available.

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