Restructuring, Impairment, and Related Charges - Summary of Restructuring Charges (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	$ 14	$ 38
Exit and other-related costs	40	13
Asset impairments and accelerated depreciation	104	5
Total	158	56
International
Restructuring Cost and Reserve [Line Items]
Total	6	14
Operating Segments | U.S. Pharmaceutical
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	2	1
Exit and other-related costs	2	1
Asset impairments and accelerated depreciation	8	0
Total	12	2
Operating Segments | Prescription Technology Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	0	0
Exit and other-related costs	1	0
Asset impairments and accelerated depreciation	17	0
Total	18	0
Operating Segments | Medical-Surgical Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	0	0
Exit and other-related costs	2	3
Asset impairments and accelerated depreciation	4	0
Total	6	3
Operating Segments | International
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	12	17
Exit and other-related costs	14	2
Asset impairments and accelerated depreciation	34	4
Total	60	23
Corporate
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	0	20
Exit and other-related costs	21	7
Asset impairments and accelerated depreciation	41	1
Total	$ 62	$ 28