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Number of sites that hazardous substances were allegedly disposed at.

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Legal Settlements, Annual Installment Amounts to be Paid

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Legal Settlements, Installment Period

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Legal Settlements, Number of Installments

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Loss Contingency, Number of Additional Defendants

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Loss Contingency, Number of Cases Consolidated

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Loss Contingency, Number of Cities Filed On Behalf Of

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Loss Contingency Number of Relators

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Loss Contingency Number of States Filed On Behalf Of

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Loss Contingency, Party Substitution Period to Prevent Case Dismissal

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Motion Granted to Stay Proceedings, Period

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- Definition

Number of Sites Selected for Preferred Remedy

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- Definition

Opioid Stewardship Act, Annual Surcharge on Licensed Manufacturers and Distributors of Opioids

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- Definition

The number of sites requiring environmental conditions to be addressed.

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- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

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Undiscounted amount of the accrual for environmental loss contingencies.

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Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Number of claims dismissed.

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The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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The total number of new claims filed pertaining to a loss contingency during the period.

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Number of plaintiffs that have filed claims pertaining to a loss contingency.

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Number of pending claims pertaining to a loss contingency.

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The amount of cash paid for the settlement of litigation or for other legal issues during the period.

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Estimated time frame of disbursements over which the accrued or presently unrecognized amounts may be paid out for an individual site.

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Commitments and Contingent Liabilities (Details) $ in Millions												1 Months Ended		12 Months Ended				16 Months Ended
	May 03, 2019 USD ($) installment	Mar. 19, 2019	Feb. 25, 2019	Jan. 08, 2019 municipality	Dec. 29, 2018 county	Dec. 12, 2018 defendant	Apr. 03, 2018 state city	Dec. 30, 2017 investment_fund	Dec. 29, 2017 investment_fund	Oct. 17, 2017 case	Apr. 16, 2013 defendant state relator	Sep. 30, 2017 state	Jan. 31, 2017 USD ($)	Mar. 31, 2019 USD ($) site case	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2019 USD ($) site state_attorney state case	Aug. 31, 2018 case	Apr. 30, 2018 USD ($)	Oct. 09, 2017 case
Loss Contingencies [Line Items]
Payments for legal settlements														$ 0.0	$ 0.0	$ 150.0
In re McKesson Corporation Derivative Litigation
Loss Contingencies [Line Items]
Number of actions consolidated \| case																					2
Police & Fire Ret. Sys. of the City of Detroit v. McKesson Corporation, et al., Amalgamated Bank v. McKesson Corporation, et al., and Greene v. McKesson Corporation, et al.
Loss Contingencies [Line Items]
Number of lawsuits filed \| case										3
United States ex rel. Manchester v. Purdue Pharma, L.P., et al
Loss Contingencies [Line Items]
Period within which party can be substituted			90 days
Polygon European Equity Opportunity Master Fund et al. v. McKesson Europe Holdings GmbH & Co. KGaA
Loss Contingencies [Line Items]
Number of plaintiffs \| investment_fund									2
Davidson Kempner International (BVI) Ltd. et al. v. McKesson Europe Holdings GmbH & Co. KGaA
Loss Contingencies [Line Items]
Number of plaintiffs \| investment_fund								4
United States ex rel. Nguyen v. McKesson Corp., et al
Loss Contingencies [Line Items]
Number of states filed on behalf of \| state							30
Granted period on motion to stay		90 days
Number of cities filed on behalf of \| city							2
The Great Atlantic & Pacific Tea Company, Inc., et al
Loss Contingencies [Line Items]
Alleged preferential transfers sought to be recovered														$ 68.0
In re McKesson Corporation Stockholder Derivative Litigation
Loss Contingencies [Line Items]
Number of actions consolidated \| case										4
Drug Enforcement Administration, Department of Justice and U.S. Attorneys' Investigative Claims
Loss Contingencies [Line Items]
Payments for legal settlements													$ 150.0
Litigation pre-tax charge																	$ 150.0
Anti-Kickback Claim
Loss Contingencies [Line Items]
Number of states filed on behalf of \| state											21
Number of relators \| relator											2
Number of additional defendants \| defendant											5
Civil Investigative Demands by the U.S. Attorney’s Office for the Eastern District of New York
Loss Contingencies [Line Items]
Number of lawsuits filed \| case																			2
Investigation into Factors Contributing to Increase in Opioid-related Hospitalizations and Deaths
Loss Contingencies [Line Items]
Number of complaints served \| case														240				240
Number of states filed on behalf of \| state												40						37
Number of plaintiffs \| state_attorney																		16
Number of dismissed cases				21	8
Investigation into Factors Contributing to Increase in Opioid-related Hospitalizations and Deaths \| In re: National Prescription Opiate Litigation
Loss Contingencies [Line Items]
Number of complaints served \| case														1,700				1,700
New York Opioid Statute
Loss Contingencies [Line Items]
Opioid Stewardship Act, Annual Surcharge on Licensed Manufacturers and Distributors of Opioids																				$ 100.0
Environmental Litigation
Loss Contingencies [Line Items]
Number of sites \| site														5				5
Remediation costs														$ 10.0				$ 10.0
Hazardous substance sites, number \| site														14
Number of sites selected for preferred remediation \| site														1				1
Estimated environmental assessment and cleanup costs														$ 1,380.0
Estimated loss														$ 23.1				$ 23.1
Environmental Litigation \| Minimum
Loss Contingencies [Line Items]
Time frame of disbursements														Apr. 01, 2019
Environmental Litigation \| Maximum
Loss Contingencies [Line Items]
Time frame of disbursements														Mar. 31, 2049
Subsequent Event \| Investigation into Factors Contributing to Increase in Opioid-related Hospitalizations and Deaths \| State of West Virginia ex rel. Patrick Morrisey v. McKesson Corp
Loss Contingencies [Line Items]
Payments for legal settlements	$ 14.5
Number of installments \| installment	5
Amount to be paid in each installment	$ 4.5
Installment payment period	5 years
Officer [Member] \| Evanston Police Pension Fund v. McKesson Corporation
Loss Contingencies [Line Items]
Number of additional defendants \| defendant						2