Sale of Receivables (Details)	12 Months Ended
	Mar. 31, 2020 USD ($) extension	Mar. 31, 2019 USD ($)	Oct. 01, 2019 EUR (€)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Extension term	1 year
Gain (loss) on sale of receivables		$ 0
Transfer of Financial Assets Accounted for as Sales, Deferred Purchase Price [Roll Forward]
Transfers of receivables		464,000,000
Collections		521,000,000
Operating cash flow effect		(57,000,000)
Purchasers
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Receivables facility, amount				$ 750,000,000	$ 600,000,000
Availability under receivable facility	$ 750,000,000
Drawn amount	$ 750,000,000
Number of extensions | extension	1
Gain (loss) on sale of receivables	$ 0
Transfer of Financial Assets Accounted for as Sales, Deferred Purchase Price [Roll Forward]
Beginning balance	574,000,000	233,000,000
Transfers of receivables	1,214,000,000	5,435,000,000
Collections	(1,265,000,000)	(4,393,000,000)
Change in funding availability	2,000,000	(246,000,000)
Facility amendments	(525,000,000)	(457,000,000)
Fair value adjustment	0	2,000,000
Ending balance	0	574,000,000
DE Purchasers
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Receivables facility, amount	225,000,000		€ 200,000,000
Availability under receivable facility	116,000,000
Drawn amount	$ 105,000,000
Number of extensions | extension	1
Extension term	1 year
Transfer of Financial Assets Accounted for as Sales, Deferred Purchase Price [Roll Forward]
Beginning balance	$ 0
Transfers of receivables	996,000,000
Collections	(879,000,000)
Change in funding availability	(14,000,000)
Ending balance	103,000,000	$ 0
Receivable	$ 11,000,000