Restructuring, Impairment, and Related Charges - Summary of Details for Charges Recorded (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	$ 104	$ 47	$ 154
Exit-related costs	59	79	164
Asset impairments and accelerated depreciation	56	30	34
Total	219	156	352
Operating Segments | U.S. Pharmaceutical
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	10	12	46
Exit-related costs	11	1	9
Asset impairments and accelerated depreciation	0	10	6
Total	21	23	61
Operating Segments | International
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	22	2	51
Exit-related costs	17	13	83
Asset impairments and accelerated depreciation	46	6	24
Total	85	21	158
Operating Segments | Medical-Surgical Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	(1)	4	18
Exit-related costs	4	19	20
Asset impairments and accelerated depreciation	1	1	3
Total	4	24	41
Operating Segments | Prescription Technology Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	4	(1)	3
Exit-related costs	0	0	0
Asset impairments and accelerated depreciation	0	0	0
Total	4	(1)	3
Corporate
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	69	30	36
Exit-related costs	27	46	52
Asset impairments and accelerated depreciation	9	13	1
Total	$ 105	$ 89	$ 89