Commitments and Contingent Liabilities - Narrative (Details) complaint in Thousands				3 Months Ended
	Apr. 03, 2018 state	Apr. 03, 2018 city	May 17, 2013 USD ($)	Jun. 30, 2019 state_attorney complaint	Jun. 30, 2019 state complaint	Jun. 30, 2019 municipality	Jun. 30, 2019 case
In re: National Prescription Opiate Litigation
Loss Contingencies [Line Items]
Complaints filed against the entity				2	2	21	245
Number of plaintiffs				19	30
United States ex rel. Omni Healthcare Inc. v. McKesson Corporation, et al.
Loss Contingencies [Line Items]
Number of plaintiffs	30	2
Minimum | True Health Chiropractic Inc., et al. v. McKesson Corporation, et al.
Loss Contingencies [Line Items]
Loss Contingency, Damages Sought, Value			$ 500
Maximum | True Health Chiropractic Inc., et al. v. McKesson Corporation, et al.
Loss Contingencies [Line Items]
Loss Contingency, Damages Sought, Value			$ 1,500