Restructuring, Impairment and Related Charges - Summary of Restructuring Charges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	$ 16	$ 19	$ 54	$ 23
Exit and other-related costs	15	19	28	33
Asset impairments and accelerated depreciation	29	7	34	12
Total	60	45	116	68
Operating Segments | U.S. Pharmaceutical
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	6	3	7	2
Exit and other-related costs	4	0	5	0
Asset impairments and accelerated depreciation	0	0	0	0
Total	10	3	12	2
Operating Segments | International
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	3	5	20	4
Exit and other-related costs	5	4	7	6
Asset impairments and accelerated depreciation	27	3	31	6
Total	35	12	58	16
Operating Segments | Medical-Surgical Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	3	1	3	1
Exit and other-related costs	(1)	2	2	4
Asset impairments and accelerated depreciation	1	0	1	1
Total	3	3	6	6
Operating Segments | Prescription Technology Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	0	0	0	0
Exit and other-related costs	0	0	0	0
Asset impairments and accelerated depreciation	0	0	0	0
Total	0	0	0	0
Corporate
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	4	10	24	16
Exit and other-related costs	7	13	14	23
Asset impairments and accelerated depreciation	1	4	2	5
Total	$ 12	$ 27	$ 40	$ 44