XML 65 R54.htm IDEA: XBRL DOCUMENT
v3.21.2

Commitments and Contingent Liabilities - Narrative (Details) |  |  | 2 Months Ended | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Jul. 21, 2021 USD ($) distributor | Jul. 20, 2021 USD ($) distributor | Sep. 30, 2021 USD ($) | Jun. 30, 2021 USD ($) case state stateAttorney | Mar. 31, 2021 USD ($) | Apr. 30, 2018 USD ($)
National Prescription Opioid Litigation |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Pre-tax expenses related to estimated litigation liability |  |  |  | $ 74,000,000 | $ 8,100,000,000 |
After-tax expenses related to estimated litigation liability |  |  |  | 61,000,000 | $ 6,800,000,000 |
Total litigation liabilities |  |  |  | 8,141,000,000 |  |
National Prescription Opioid Litigation | State of New York |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Pre-tax expenses related to estimated litigation liability |  |  |  | 27,000,000 |  |
After-tax expenses related to estimated litigation liability |  |  |  | 22,000,000 |  |
National Prescription Opioid Litigation | State and local governmental entities |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Pre-tax expenses related to estimated litigation liability |  |  |  | 47,000,000 |  |
After-tax expenses related to estimated litigation liability |  |  |  | 39,000,000 |  |
State Opioid Statutes |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Aggregate annual surcharge on licensed manufacturers and distributors of opioids |  |  |  |  |  | $ 100,000,000
Total litigation liabilities |  |  |  | 50,000,000 |  |
After-tax accrual |  |  |  | $ 37,000,000 |  |
National Prescription Opioid Litigation |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Complaints filed against the entity | case |  |  |  | 2,900 |  |
Canada | National Prescription Opioid Litigation |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Complaints filed against the entity | case |  |  |  | 3 |  |
Canada | National Prescription Opioid Litigation | Governmental entities |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Complaints filed against the entity | case |  |  |  | 2 |  |
Canada | National Prescription Opioid Litigation | An individual |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Complaints filed against the entity | case |  |  |  | 1 |  |
Pending |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Complaints filed against the entity | case |  |  |  | 300 |  |
Number of states in which court cases are pending | state |  |  |  | 38 |  |
Number of attorney generals that have filed claims | stateAttorney |  |  |  | 26 |  |
Pending | National Prescription Opioid Litigation |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Number of cases selected for remand to other federal courts | case |  |  |  | 3 |  |
Pending | National Prescription Opioid Litigation | Expected |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Expected settlement payment |  |  | $ 482,000,000 |  |  |
Pending | National Prescription Opioid Litigation | Subsequent Event |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Number of other national distributors named in suit | distributor | 2 |  |  |  |  |
Number of distributors | distributor | 3 |  |  |  |  |
Award payable under proposed framework | $ 7,900,000,000 |  |  |  |  |
Portion of settlement to be paid by the Company | 38.10% |  |  |  |  |
Portion of settlement award to be used by state and local government for remediation (percent) | 85.00% |  |  |  |  |
Pending | National Prescription Opioid Litigation | Subsequent Event | State of New York |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Number of other national distributors named in suit | distributor |  | 2 |  |  |  |
Award payable under proposed framework |  | $ 1,200,000,000 |  |  |  |
Portion of settlement to be paid by the Company |  | 38.10% |  |  |  |
Pending | Canada |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Complaints filed against the entity | case |  |  |  | 3 |  |
Pending | Three Largest U.S. Pharmaceutical Distributors | National Prescription Opioid Litigation | Subsequent Event |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Award payable under proposed framework | $ 21,000,000,000 |  |  |  |  |
Period over which award would be payable under proposed framework | 18 years |  |  |  |  |

X
- Definition Litigation Settlement, Amount Awarded to Other Party, Percentage of Total Settlement Award + References No definition available. + Details
Name: | mck_LitigationSettlementAmountAwardedToOtherPartyPercentageOfTotalSettlementAward
Namespace Prefix: | mck_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Litigation Settlement, Award Amount To Be Used by State and Local Government + References No definition available. + Details
Name: | mck_LitigationSettlementAwardAmountToBeUsedByStateAndLocalGovernment
Namespace Prefix: | mck_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Loss Contingency Accrual, After Tax + References No definition available. + Details
Name: | mck_LossContingencyAccrualAfterTax
Namespace Prefix: | mck_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Loss Contingency Accrual, Period Increase (Decrease), Net of Tax + References No definition available. + Details
Name: | mck_LossContingencyAccrualPeriodIncreaseDecreaseNetOfTax
Namespace Prefix: | mck_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Loss Contingency, Number of Other Defendants + References No definition available. + Details
Name: | mck_LossContingencyNumberOfOtherDefendants
Namespace Prefix: | mck_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Loss Contingency, Number of Cases Selected For Remand to Other Federal Courts + References No definition available. + Details
Name: | mck_LossContingencyNumberofCasesSelectedForRemandtoOtherFederalCourts
Namespace Prefix: | mck_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Loss Contingency, Number of State Attorney Generals + References No definition available. + Details
Name: | mck_LossContingencyNumberofStateAttorneyGenerals
Namespace Prefix: | mck_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Loss Contingency, Number of States + References No definition available. + Details
Name: | mck_LossContingencyNumberofStates
Namespace Prefix: | mck_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Loss Contingency, Settlement Agreement, Award Payment Period + References No definition available. + Details
Name: | mck_LossContingencySettlementAgreementAwardPaymentPeriod
Namespace Prefix: | mck_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Opioid Stewardship Act, Annual Surcharge on Licensed Manufacturers and Distributors of Opioids + References No definition available. + Details
Name: | mck_OpioidStewardshipActAnnualSurchargeOnLicensedManufacturersAndDistributorsOfOpioids
Namespace Prefix: | mck_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount awarded to other party in judgment or settlement of litigation. + References No definition available. + Details
Name: | us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of loss contingency liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349 + Details
Name: | us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase (decrease) in loss contingency liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349 + Details
Name: | us-gaap_LossContingencyAccrualCarryingValuePeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of defendants named in a legal action. + References No definition available. + Details
Name: | us-gaap_LossContingencyNumberOfDefendants
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of pending claims pertaining to a loss contingency. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349 + Details
Name: | us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of cash paid for the settlement of litigation or for other legal issues during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3536-108585 + Details
Name: | us-gaap_PaymentsForLegalSettlements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=mck_NationalPrescriptionOpiateLitigationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=mck_StateOfNewYorkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=mck_StateAndLocalGovernmentalEntitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=mck_StateOpioidStatutesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=mck_NationalPrescriptionOpiateLitigationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=country_CA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=mck_GovernmentalEntitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=mck_IndividualClaimantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LitigationStatusAxis=us-gaap_PendingLitigationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=mck_ThreeLargestU.S.PharmaceuticalDistributorsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |