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Restructuring, Impairment and Related Charges - Summary of Restructuring Activity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Restructuring Reserve [Roll Forward]
Restructuring, impairment and related charges	$ 136	$ 110	$ 204	$ 288
Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance			150
Restructuring, impairment and related charges	37	71	103	215
Non-cash charges			(17)
Cash Payments			(86)
Other			(18)
Ending balance	132		132
Operating Segments \| U.S. Pharmaceutical and Specialty Solutions \| Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance			31
Restructuring, impairment and related charges	3	4	4	17
Non-cash charges			0
Cash Payments			(6)
Other			(1)
Ending balance	28		28
Operating Segments \| European Pharmaceutical Solutions \| Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance			38
Restructuring, impairment and related charges	5	4	18	4
Non-cash charges			(8)
Cash Payments			(13)
Other			(4)
Ending balance	31		31
Operating Segments \| Medical-Surgical Solutions \| Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance			15
Restructuring, impairment and related charges	6	6	12	24
Non-cash charges			(1)
Cash Payments			(8)
Other			(2)
Ending balance	16		16
Operating Segments \| Other \| Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance			29
Restructuring, impairment and related charges	0	9	2	89
Non-cash charges			0
Cash Payments			(16)
Other			(5)
Ending balance	10		10
Corporate \| Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance			37
Restructuring, impairment and related charges	23	$ 48	67	$ 81
Non-cash charges			(8)
Cash Payments			(43)
Other			(6)
Ending balance	47		47
Other accrued liabilities \| Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance			117
Ending balance	110		110
Other noncurrent liabilities \| Fiscal 2019 Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance			33
Ending balance	$ 22		$ 22