Held for Sale - Narrative (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
Dec. 11, 2019	Dec. 31, 2019	Dec. 31, 2019	Mar. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale		$ 856	$ 856	$ 0
Liabilities held for sale		471	471	$ 0
Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale		856	856
Liabilities held for sale		471	471
Held-for-sale \| German Wholesale Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment loss	$ 282	282	282
Impairment loss, after tax	$ 282	$ 282	$ 282

Impairment of Long-Lived Assets to be Disposed of, Net of Tax

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Amount classified as assets attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.

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