Litigation Settlement, Amount Awarded to Other Party, Percentage of Total Settlement to Be Used to Remediate Damages

No definition available.

Name:	mck_LitigationSettlementAmountAwardedToOtherPartyPercentageOfTotalSettlementToBeUsedToRemediateDamages
Namespace Prefix:	mck_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- 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-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Loss Contingency, Claims Settled, Number Of Jurisdictions Not Participating In Settlement

+ References

No definition available.

+ Details

Name:	mck_LossContingencyClaimsSettledNumberOfJurisdictionsNotParticipatingInSettlement
Namespace Prefix:	mck_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Loss Contingency, Number Of Cases Dismissed

+ References

No definition available.

+ Details

Name:	mck_LossContingencyNumberOfCasesDismissed
Namespace Prefix:	mck_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Loss Contingency, Number of Cities Filed On Behalf Of

+ References

No definition available.

+ Details

Name:	mck_LossContingencyNumberOfCitiesFiledOnBehalfOf
Namespace Prefix:	mck_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- 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

- Definition

Loss Contingency, Number of States Filed On Behalf Of

+ References

No definition available.

+ Details

Name:	mck_LossContingencyNumberOfStatesFiledOnBehalfOf
Namespace Prefix:	mck_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- 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

- Definition

Number Of Antitrust Settlements

+ References

No definition available.

+ Details

Name:	mck_NumberOfAntitrustSettlements
Namespace Prefix:	mck_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process.

+ References

+ Details

Name:	us-gaap_GainLossRelatedToLitigationSettlement
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

- 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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 720
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483359/720-20-50-1

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 27
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482395/460-10-55-27

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-3

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of damages awarded to the plaintiff in the legal matter.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

+ Details

Name:	us-gaap_LossContingencyDamagesAwardedValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of pending claims pertaining to a loss contingency.

+ References

+ Details

Name:	us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- 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
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (g)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25

+ Details

Name:	us-gaap_PaymentsForLegalSettlements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Cash received for the settlement of litigation during the current period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25

+ Details

Name:	us-gaap_ProceedsFromLegalSettlements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-8

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(1)(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

+ Details

Name:	us-gaap_RestrictedCash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=mck_USPharmaceuticalSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_CorporateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=mck_CorporateSegmentAndU.S.PharmaceuticalSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_CA
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=mck_IndividualClaimantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=mck_NationalPrescriptionOpiateLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=mck_StateOfAlabamaAndSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=mck_NativeAmericanTribesOtherThanCherokeeNationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=mck_SettlingGovernmentalEntitiesAndCherokeeNationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationStatusAxis=us-gaap_SettledLitigationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=mck_ThreeLargestUSPharmaceuticalDistributorsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=mck_ThreeNationalPharmaceuticalDistributorsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=mck_StateOfWestVirginiaAndSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=mck_CherokeeNationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=mck_UnitedStatesExRelHartVMcKessonCorporationEtAl15Cv00903RAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=mck_UnitedStatesExRel.OmniHealthcareInc.V.McKessonCorporationEtAl.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingent Liabilities - Narrative (Details) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Nov. 12, 2024 USD ($)	Jan. 31, 2025 USD ($)	Dec. 31, 2024 USD ($) distributor case state subdivision settlement	Dec. 31, 2023 USD ($)	Dec. 31, 2024 USD ($) distributor case state subdivision	Dec. 31, 2023 USD ($)	Mar. 31, 2024 USD ($)	Nov. 27, 2024 USD ($)	Jul. 31, 2020 state	Apr. 25, 2018 city
Loss Contingencies [Line Items]
Claims and litigation charges			$ 0	$ 0	$ 108	$ (2)
Proceeds from legal settlements			$ 31
Number of antitrust settlement \| settlement			2
Subsequent Event
Loss Contingencies [Line Items]
Proceeds from legal settlements		$ 247
U.S. Pharmaceutical
Loss Contingencies [Line Items]
Proceeds from legal settlements			$ 31	$ 23	184	$ 220
National Prescription Opioid Litigation
Loss Contingencies [Line Items]
Claims and litigation charges					114		$ 149
National Prescription Opioid Litigation \| Corporate
Loss Contingencies [Line Items]
Claims and litigation charges							(75)
National Prescription Opioid Litigation \| U.S. Pharmaceutical
Loss Contingencies [Line Items]
Claims and litigation charges							$ (74)
National Prescription Opioid Litigation \| Corporate Segment and U.S. Pharmaceutical Segment
Loss Contingencies [Line Items]
Claims and litigation charges					$ 57
National Prescription Opioid Litigation \| Canada
Loss Contingencies [Line Items]
Complaints filed against the entity \| case			4		4
National Prescription Opioid Litigation \| An individual \| Canada
Loss Contingencies [Line Items]
Complaints filed against the entity \| case			1		1
National Prescription Opioid Litigation
Loss Contingencies [Line Items]
Number of other national distributors named in suit \| distributor			2		2
Number of states in which court cases are pending \| state			48		48
Loss contingency, number of cases dismissed \| case			2,300		2,300
Portion of settlement award to be used by state and local government for remediation (as a percent)			85.00%		85.00%
Loss contingency, claims settled, number of jurisdictions not participating in settlement \| subdivision			1		1
Amounts awarded to plaintiff	$ 192
Restricted cash in escrow								$ 149
National Prescription Opioid Litigation \| State of Alabama and Subdivisions
Loss Contingencies [Line Items]
Settlement payment					$ 75
Award payable under proposed framework					$ 99
National Prescription Opioid Litigation \| Native American Tribes Other Than Cherokee Nation
Loss Contingencies [Line Items]
Litigation settlement, amount awarded to other party, percentage of total settlement to be used to remediate damages (as a percent)			0.85		0.85
National Prescription Opioid Litigation \| Settling Governmental Entities and Cherokee Nation \| Settled Litigation
Loss Contingencies [Line Items]
Settlement payment					$ 500
National Prescription Opioid Litigation \| Three Largest U.S. Pharmaceutical Distributors
Loss Contingencies [Line Items]
Settlement payment					2,000
Award payable under proposed framework					5,900
National Prescription Opioid Litigation \| Three National Pharmaceutical Distributors \| State of West Virginia and Subdivisions
Loss Contingencies [Line Items]
Settlement payment					53
Award payable under proposed framework					84
National Prescription Opioid Litigation \| Three National Pharmaceutical Distributors \| State of West Virginia and Subdivisions \| Subsequent Event
Loss Contingencies [Line Items]
Settlement payment		$ 15
National Prescription Opioid Litigation \| Three National Pharmaceutical Distributors \| Cherokee Nation
Loss Contingencies [Line Items]
Settlement payment					112
National Prescription Opioid Litigation \| Three National Pharmaceutical Distributors \| Native American Tribes Other Than Cherokee Nation
Loss Contingencies [Line Items]
Award payable under proposed framework					$ 84
United States ex rel. Hart v. McKesson Corporation, et al., 15-cv-00903-RA
Loss Contingencies [Line Items]
Number of states filed on behalf of \| state									27
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