Goodwill and Intangible Assets, Net - Schedule of Changes in the Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Goodwill [Roll Forward]
Goodwill, beginning balance		$ 10,924	$ 9,358	$ 10,924
Goodwill acquired			76	442
Acquisition accounting, transfers and other adjustments			12	35
Other changes/disposals			(6)
Goodwill impairment			(2)	(1,797)	$ (1,738)
Foreign currency translation adjustments, net			(78)	(246)
Goodwill, ending balance	$ 9,358		9,360	9,358	10,924
U.S. Pharmaceutical and Specialty Solutions
Goodwill [Roll Forward]
Goodwill, beginning balance		4,110	4,078	4,110
Goodwill acquired			0	17
Acquisition accounting, transfers and other adjustments			1	13
Other changes/disposals			(1)
Goodwill impairment			0	0
Foreign currency translation adjustments, net			(11)	(62)
Goodwill, ending balance	4,078		4,067	4,078	4,110
European Pharmaceutical Solutions
Goodwill [Roll Forward]
Goodwill, beginning balance		1,850	0	1,850
Goodwill acquired			62	52
Acquisition accounting, transfers and other adjustments			4	(5)
Other changes/disposals			0
Goodwill impairment	(1,200)	(570)	0	(1,776)	(1,300)
Foreign currency translation adjustments, net			(3)	(121)
Goodwill, ending balance	0		63	0	1,850
Medical-Surgical Solutions
Goodwill [Roll Forward]
Goodwill, beginning balance		2,070	2,451	2,070
Goodwill acquired			0	360
Acquisition accounting, transfers and other adjustments			7	21
Other changes/disposals			(5)
Goodwill impairment			0	0
Foreign currency translation adjustments, net			0	0
Goodwill, ending balance	2,451		2,453	2,451	2,070
Other
Goodwill [Roll Forward]
Goodwill, beginning balance		$ 2,894	2,829	2,894
Goodwill acquired			14	13
Acquisition accounting, transfers and other adjustments			0	6
Other changes/disposals			0
Goodwill impairment			(2)	(21)
Foreign currency translation adjustments, net			(64)	(63)
Goodwill, ending balance	$ 2,829		$ 2,777	$ 2,829	$ 2,894