Restructuring, Impairment and Related Charges - Summary of Restructuring Activity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Restructuring Reserve [Roll Forward]
Beginning balance			$ 157
Restructuring, impairment, and related charges	$ 40	$ 42	156	$ 110
Non-cash charges			(50)
Cash payments			(132)
Other			1
Ending balance	132		132
International
Restructuring Reserve [Roll Forward]
Restructuring, impairment, and related charges	131		189
Operating Segments | U.S. Pharmaceutical
Restructuring Reserve [Roll Forward]
Beginning balance			29
Restructuring, impairment, and related charges	6	7	18	9
Non-cash charges			0
Cash payments			(24)
Other			0
Ending balance	23		23
Operating Segments | International
Restructuring Reserve [Roll Forward]
Beginning balance			66
Restructuring, impairment, and related charges	16	6	74	22
Non-cash charges			(40)
Cash payments			(24)
Other			(1)
Ending balance	75		75
Operating Segments | Medical-Surgical Solutions
Restructuring Reserve [Roll Forward]
Beginning balance			22
Restructuring, impairment, and related charges	(2)	6	4	12
Non-cash charges			(1)
Cash payments			(19)
Other			0
Ending balance	6		6
Operating Segments | Prescription Technology Solutions
Restructuring Reserve [Roll Forward]
Beginning balance			1
Restructuring, impairment, and related charges	0	0	0	0
Non-cash charges			0
Cash payments			(1)
Other			0
Ending balance	0		0
Corporate
Restructuring Reserve [Roll Forward]
Beginning balance			39
Restructuring, impairment, and related charges	20	$ 23	60	$ 67
Non-cash charges			(9)
Cash payments			(64)
Other			2
Ending balance	28		28
Other accrued liabilities
Restructuring Reserve [Roll Forward]
Beginning balance			118
Ending balance	101		101
Other noncurrent liabilities
Restructuring Reserve [Roll Forward]
Beginning balance			39
Ending balance	$ 31		$ 31