Revenue - Change in Contract Liabilities (Details) - USD ($) $ in Millions	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Change In Contract With Customer, Liability [Roll Forward]
Balance, beginning of period	$ 1,756	$ 1,886
Deferred revenue	1,355	1,400
Recognition of deferred revenue	(1,432)	(1,416)
Currency translation adjustment	80	(48)
Other	(88)	(22)
Balance, end of period	1,671	$ 1,800
Discontinued Operations - Held for sale | HHS Business
Capitalized Contract Cost [Line Items]
Contract liabilities reclassified as liabilities related to assets held for sale	$ 51