Hedging Activities - Derivative Instruments Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2020	Mar. 31, 2020
Derivatives designated for hedge accounting
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	$ 101	$ 294
Fair value of derivative, liability	65	19
Derivatives designated for hedge accounting \| Cross currency swap \| Prepaid expenses and other
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	20	112
Derivatives designated for hedge accounting \| Cross currency swap \| Other accrued liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative, liability	12	19
Derivatives designated for hedge accounting \| Cross currency swap \| Prepaid expenses and other/Other accrued liabilities
Derivatives, Fair Value [Line Items]
U.S. Dollar notional amount, asset	925	1,279
Derivatives designated for hedge accounting \| Cross currency swap \| Other noncurrent assets
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	81	182
Derivatives designated for hedge accounting \| Cross currency swap \| Other noncurrent liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative, liability	42	0
Derivatives designated for hedge accounting \| Cross currency swap \| Non-current Asset / Liability
Derivatives, Fair Value [Line Items]
U.S. Dollar notional amount, asset	3,313	3,313
Derivatives designated for hedge accounting \| Forward starting interest rate swaps \| Other accrued liabilities
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	0	0
Fair value of derivative, liability	11	0
U.S. Dollar notional amount, asset	1,203	0
Derivatives not designated for hedge accounting
Derivatives, Fair Value [Line Items]
Fair value of derivative, asset	1	2
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	1	2
Fair value of derivative, liability	0	0
U.S. Dollar notional amount, asset	32	24
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	$ 13	$ 5

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

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-Name Accounting Standards Codification
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Nominal or face amount used to calculate payments on the derivative liability.

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