Restructuring and Asset Impairment Charges - Summary of Restructuring Charges (Details) - Strategic Growth Initiative Plan - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Dec. 31, 2018	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	$ 41	$ 61
Exit-related costs	6	75
Asset impairments and accelerated depreciation and amortization	3	25
Net restructuring charges recognized	50	161
Corporate
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	31	31
Exit-related costs	0	0
Asset impairments and accelerated depreciation and amortization	0	0
Net restructuring charges recognized	31	31
Operating Segments | U.S. Pharmaceutical and Specialty Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	1	4
Exit-related costs	1	7
Asset impairments and accelerated depreciation and amortization	2	6
Net restructuring charges recognized	4	17
Operating Segments | Medical-Surgical Solutions
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	0	10
Exit-related costs	5	12
Asset impairments and accelerated depreciation and amortization	1	2
Net restructuring charges recognized	6	24
Operating Segments | Other
Restructuring Cost and Reserve [Line Items]
Severance and employee-related costs, net	9	16
Exit-related costs	0	56
Asset impairments and accelerated depreciation and amortization	0	17
Net restructuring charges recognized	$ 9	$ 89