Goodwill and Intangible Assets, Net - Schedule of Information Regarding Intangible Assets (Details) - USD ($) $ in Millions	9 Months Ended
	Dec. 31, 2021	Mar. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 5,061	$ 6,646
Accumulated Amortization	(2,931)	(3,768)
Net Carrying Amount	2,130	2,878
European Assets Held for Sale | Held-for-sale
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 452
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Amortization Period (Years)	12 years
Gross Carrying Amount	$ 2,842	3,739
Accumulated Amortization	(1,718)	(2,269)
Net Carrying Amount	$ 1,124	1,470
Service agreements
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Amortization Period (Years)	9 years
Gross Carrying Amount	$ 1,083	1,081
Accumulated Amortization	(558)	(513)
Net Carrying Amount	525	568
Pharmacy licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	0	497
Accumulated Amortization	0	(244)
Net Carrying Amount	$ 0	253
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Amortization Period (Years)	12 years
Gross Carrying Amount	$ 816	925
Accumulated Amortization	(371)	(394)
Net Carrying Amount	$ 445	531
Technology
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Amortization Period (Years)	2 years
Gross Carrying Amount	$ 128	150
Accumulated Amortization	(113)	(122)
Net Carrying Amount	$ 15	28
Other
Finite-Lived Intangible Assets [Line Items]
Weighted- Average Remaining Amortization Period (Years)	8 years
Gross Carrying Amount	$ 192	254
Accumulated Amortization	(171)	(226)
Net Carrying Amount	$ 21	$ 28