Restructuring and Asset Impairment Charges - Summary of Restructuring Activity (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance	$ 150
Net restructuring charges recognized	23	$ 69
Non-cash charges	(5)
Cash Payments	(27)
Other	(8)
Ending balance	133
Strategic Growth Initiative Plan
Restructuring Reserve [Roll Forward]
Net restructuring charges recognized	4
Operating Segments | U.S. Pharmaceutical and Specialty Solutions | Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance	31
Net restructuring charges recognized	(1)	8
Non-cash charges	0
Cash Payments	(1)
Other	0
Ending balance	29
Operating Segments | European Pharmaceutical Solutions | Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance	38
Net restructuring charges recognized	3
Non-cash charges	(3)
Cash Payments	(7)
Other	1
Ending balance	32
Operating Segments | Medical-Surgical Solutions | Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance	15
Net restructuring charges recognized	3	12
Non-cash charges	(1)
Cash Payments	0
Other	0
Ending balance	17
Operating Segments | Other | Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance	29
Net restructuring charges recognized	1	38
Non-cash charges	0
Cash Payments	(12)
Other	(6)
Ending balance	12
Corporate | Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance	37
Net restructuring charges recognized	17	$ 11
Non-cash charges	(1)
Cash Payments	(7)
Other	(3)
Ending balance	$ 43