Commitments and Contingent Liabilities - Other Litigation and Claims (Narrative) (Details)	May 17, 2013 USD ($) plaintiff	Apr. 25, 2018 city
United States ex rel. Omni Healthcare Inc. v. McKesson Corporation, et al.
Loss Contingencies [Line Items]
Number of cities filed on behalf of | city		33
True Health Chiropractic Inc., et al. v. McKesson Corporation, et al., No. CV-13-02219
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff	2
Amounts awarded to plaintiff | $	$ 6,500