Commitments and Contingent Liabilities	3 Months Ended
Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Commitments and Contingent Liabilities In addition to commitments and obligations in the ordinary course of business, we are subject to various claims, including claims with customers and vendors, pending and potential legal actions for damages, investigations relating to governmental laws and regulations and other matters arising out of the normal conduct of our business. As described below, many of these proceedings are at preliminary stages and many seek an indeterminate amount of damages. When a loss is considered probable and reasonably estimable, we record a liability in the amount of our best estimate for the ultimate loss. However, the likelihood of a loss with respect to a particular contingency is often difficult to predict and determining a meaningful estimate of the loss or a range of loss may not be practicable based on the information available and the potential effect of future events and decisions by third parties that will determine the ultimate resolution of the contingency. Moreover, it is not uncommon for such matters to be resolved over many years, during which time relevant developments and new information must be reevaluated at least quarterly to determine both the likelihood of potential loss and whether it is possible to reasonably estimate a range of possible loss. When a loss is probable but a reasonable estimate cannot be made, disclosure of the proceeding is provided. Disclosure also is provided when it is reasonably possible that a loss will be incurred or when it is reasonably possible that the amount of a loss will exceed the recorded provision. We review all contingencies at least quarterly to determine whether the likelihood of loss has changed and to assess whether a reasonable estimate of the loss or range of loss can be made. As discussed above, development of a meaningful estimate of loss or a range of potential loss is complex when the outcome is directly dependent on negotiations with or decisions by third parties, such as regulatory agencies, the court system and other interested parties. Such factors bear directly on whether it is possible to reasonably estimate a range of potential loss and boundaries of high and low estimates. Significant developments in previously reported proceedings and in other litigation and claims, since the filing of our 2016 Annual Report are set out below. Unless otherwise stated, we are currently unable to estimate a range of reasonably possible losses for the unresolved proceedings described below. Should any one or a combination of more than one of these proceedings be successful, or should we determine to settle any or a combination of these matters, we may be required to pay substantial sums, become subject to the entry of an injunction or be forced to change the manner in which we operate our business, which could have a material adverse impact on our financial position or results of operations. Litigation, Government Subpoenas and Investigations As previously disclosed, on September 7, 2007, McKesson Specialty Arizona Inc. was served with a complaint filed in the New York Supreme Court, New York County by PSKW, LLC, alleging that McKesson Specialty Arizona misappropriated trade secrets and confidential information in launching its LoyaltyScript® program, PSKW, LLC v. McKesson Specialty Arizona Inc., Index No. 602921/07. The trial and post-trial briefing have concluded. The court has not yet entered an order of judgment. As previously disclosed, on May 21, 2014, four hedge funds managed by Magnetar Capital filed a complaint against Celesio Holdings Deutschland GmbH & Co. KGaA (formerly known as “Dragonfly GmbH & Co KGaA” and “McKesson Deutschland GmbH & Co. KGaA) (“Dragonfly” or “Celesio Holdings”), a wholly-owned subsidiary of the Company, in a German court in Frankfurt, Germany, alleging that Celesio Holdings violated German takeover law in connection with the Company’s acquisition of Celesio by paying more to some holders of Celesio’s convertible bonds than it paid to the shareholders of Celesio’s stock, Magnetar Capital Master Fund Ltd. et al. v. Dragonfly GmbH & Co KGaA, No. 3- 05 O 44/14. On December 5, 2014, the court dismissed Magnetar’s lawsuit in Celesio Holdings’ favor. Magnetar subsequently appealed that ruling. On January 19, 2016, the Appellate Court reversed the lower court’s ruling and entered judgment against Celesio Holdings. Celesio Holdings has appealed this judgment. From time to time, the Company receives subpoenas or requests for information from various government agencies. The Company generally responds to such subpoenas and requests in a cooperative, thorough and timely manner. For example, the Company was served with a Civil Investigative Demand by the U.S. Attorney’s Office for the Southern District of New York relating to certain business analytics tools offered to its customers. As another example, the Company was served with a subpoena by the Office of Inspector General to the U.S. Department of Health and Human Services concerning billing and coding services relating to ambulance providers. The Company is currently responding to these requests. These responses sometimes require time and effort and can result in considerable costs being incurred by the Company. Such subpoenas and requests also can lead to the assertion of claims or the commencement of civil or criminal legal proceedings against the Company and other members of the health care industry, as well as to settlements.

Commitments and Contingent Liabilities

In addition to commitments and obligations in the ordinary course of business, we are subject to various claims, including claims with customers and vendors, pending and potential legal actions for damages, investigations relating to governmental laws and regulations and other matters arising out of the normal conduct of our business. As described below, many of these proceedings are at preliminary stages and many seek an indeterminate amount of damages.

When a loss is considered probable and reasonably estimable, we record a liability in the amount of our best estimate for the ultimate loss. However, the likelihood of a loss with respect to a particular contingency is often difficult to predict and determining a meaningful estimate of the loss or a range of loss may not be practicable based on the information available and the potential effect of future events and decisions by third parties that will determine the ultimate resolution of the contingency. Moreover, it is not uncommon for such matters to be resolved over many years, during which time relevant developments and new information must be reevaluated at least quarterly to determine both the likelihood of potential loss and whether it is possible to reasonably estimate a range of possible loss. When a loss is probable but a reasonable estimate cannot be made, disclosure of the proceeding is provided.

Disclosure also is provided when it is reasonably possible that a loss will be incurred or when it is reasonably possible that the amount of a loss will exceed the recorded provision. We review all contingencies at least quarterly to determine whether the likelihood of loss has changed and to assess whether a reasonable estimate of the loss or range of loss can be made. As discussed above, development of a meaningful estimate of loss or a range of potential loss is complex when the outcome is directly dependent on negotiations with or decisions by third parties, such as regulatory agencies, the court system and other interested parties. Such factors bear directly on whether it is possible to reasonably estimate a range of potential loss and boundaries of high and low estimates.

Significant developments in previously reported proceedings and in other litigation and claims, since the filing of our 2016 Annual Report are set out below. Unless otherwise stated, we are currently unable to estimate a range of reasonably possible losses for the unresolved proceedings described below. Should any one or a combination of more than one of these proceedings be successful, or should we determine to settle any or a combination of these matters, we may be required to pay substantial sums, become subject to the entry of an injunction or be forced to change the manner in which we operate our business, which could have a material adverse impact on our financial position or results of operations.

Litigation, Government Subpoenas and Investigations

As previously disclosed, on September 7, 2007, McKesson Specialty Arizona Inc. was served with a complaint filed in the New York Supreme Court, New York County by PSKW, LLC, alleging that McKesson Specialty Arizona misappropriated trade secrets and confidential information in launching its LoyaltyScript® program, PSKW, LLC v. McKesson Specialty Arizona Inc., Index No. 602921/07. The trial and post-trial briefing have concluded. The court has not yet entered an order of judgment.

As previously disclosed, on May 21, 2014, four hedge funds managed by Magnetar Capital filed a complaint against Celesio Holdings Deutschland GmbH & Co. KGaA (formerly known as “Dragonfly GmbH & Co KGaA” and “McKesson Deutschland GmbH & Co. KGaA) (“Dragonfly” or “Celesio Holdings”), a wholly-owned subsidiary of the Company, in a German court in Frankfurt, Germany, alleging that Celesio Holdings violated German takeover law in connection with the Company’s acquisition of Celesio by paying more to some holders of Celesio’s convertible bonds than it paid to the shareholders of Celesio’s stock, Magnetar Capital Master Fund Ltd. et al. v. Dragonfly GmbH & Co KGaA, No. 3- 05 O 44/14. On December 5, 2014, the court dismissed Magnetar’s lawsuit in Celesio Holdings’ favor. Magnetar subsequently appealed that ruling. On January 19, 2016, the Appellate Court reversed the lower court’s ruling and entered judgment against Celesio Holdings. Celesio Holdings has appealed this judgment.

From time to time, the Company receives subpoenas or requests for information from various government agencies. The Company generally responds to such subpoenas and requests in a cooperative, thorough and timely manner. For example, the Company was served with a Civil Investigative Demand by the U.S. Attorney’s Office for the Southern District of New York relating to certain business analytics tools offered to its customers. As another example, the Company was served with a subpoena by the Office of Inspector General to the U.S. Department of Health and Human Services concerning billing and coding services relating to ambulance providers. The Company is currently responding to these requests. These responses sometimes require time and effort and can result in considerable costs being incurred by the Company. Such subpoenas and requests also can lead to the assertion of claims or the commencement of civil or criminal legal proceedings against the Company and other members of the health care industry, as well as to settlements.