Debt Instrument, Days Available For Borrowing

No definition available.

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Period Type:	duration

- Definition

Debt Instrument, Number Of Separate Borrowings

+ References

No definition available.

+ Details

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The maximum amount of borrowing capacity under a line of credit that is available as of the balance sheet date for a specific purpose other than for financing goods acquired for inventory or imminent delivery to a customer.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
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+ Details

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Balance Type:	debit
Period Type:	duration

- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Debt and Financing Activities - Revolving Credit Facilities (Details)		3 Months Ended	12 Months Ended
	Nov. 07, 2022 USD ($)	Dec. 31, 2023 USD ($)	Mar. 31, 2024 USD ($) borrowing	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)
Line of Credit Facility [Line Items]
Total debt			$ 5,629,000,000	$ 5,594,000,000
Line of Credit
Line of Credit Facility [Line Items]
Committed balance					$ 7,000,000
Uncommitted balance					111,000,000
Term Loan
Line of Credit Facility [Line Items]
Term of facility		3 months
Total debt		$ 500,000,000
Term Loan \| Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate		1.10%
Senior Unsecured Credit Facility (the 2022 Credit Facility) \| Unsecured debt \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit facility borrowing capacity	$ 4,000,000,000
Senior Unsecured Credit Facility (the 2022 Credit Facility), Canadian Dollar, British Pound Sterling, and Euros Sublimit \| Unsecured debt \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit facility borrowing capacity	3,600,000,000
Amount borrowed under facility			0	0
Credit facility outstanding			$ 0	0
Senior Unsecured Credit Facility (the 2020 Credit Facility) \| Unsecured debt \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Credit facility borrowing capacity	$ 4,000,000,000
Term of facility	5 years
Senior Unsecured Credit Facility (the 2020 Credit Facility), Canadian Dollar, British Pound Sterling, and Euros Sublimit \| Unsecured debt \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Amount borrowed under facility				$ 0	$ 0
Credit facility outstanding	$ 0
2022 Term Loan Credit Facility \| Line of Credit
Line of Credit Facility [Line Items]
Credit facility borrowing capacity	$ 500,000,000
Debt instrument, number of separate borrowings \| borrowing			3
Debt instrument, days available for borrowing	90 days