Restructuring, Impairment and Related Charges - Summary of Restructuring Charges (Details) - Fiscal 2019 Initiatives - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	$ 17	$ 10	$ 21	$ 24
Exit-related costs	19	63	33	98
Asset impairments and accelerated depreciation and amortization	7	2	12	22
Net restructuring charges recognized	43	75	66	144
Operating Segments | U.S. Pharmaceutical and Specialty Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	2	0	1	3
Exit-related costs	0	5	0	6
Asset impairments and accelerated depreciation and amortization	0	0	0	4
Net restructuring charges recognized	2	5	1	13
Operating Segments | European Pharmaceutical Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	3		2
Exit-related costs	4		5
Asset impairments and accelerated depreciation and amortization	3		6
Net restructuring charges recognized	10		13
Operating Segments | Medical-Surgical Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	1	0	1	10
Exit-related costs	2	5	4	7
Asset impairments and accelerated depreciation and amortization	0	1	1	1
Net restructuring charges recognized	3	6	6	18
Operating Segments | Other
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	1	6	1	7
Exit-related costs	0	35	1	56
Asset impairments and accelerated depreciation and amortization	0	1	0	17
Net restructuring charges recognized	1	42	2	80
Corporate
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	10	4	16	4
Exit-related costs	13	18	23	29
Asset impairments and accelerated depreciation and amortization	4	0	5	0
Net restructuring charges recognized	$ 27	$ 22	$ 44	$ 33