Debt Instrument, Days Available For Borrowing

No definition available.

Name:	mck_DebtInstrumentDaysAvailableForBorrowing
Namespace Prefix:	mck_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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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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

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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

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+ Details

Name:	us-gaap_LineOfCredit
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

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
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

+ Details

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

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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+ Details

Name:	us-gaap_LongTermDebt
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://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:	debit
Period Type:	duration

- Details

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Data Type:	na
Balance Type:
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- Details

Name:	us-gaap_VariableRateAxis=mck_SecuredOvernightFinancingRateSOFRMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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- Details

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Balance Type:
Period Type:

- Details

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- Details

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- Details

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- Details

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- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
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Debt and Financing Activities - Revolving Credit Facilities (Details) - USD ($)		3 Months Ended	12 Months Ended
	Nov. 07, 2022	Dec. 31, 2022	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Line of Credit Facility [Line Items]
Total debt			$ 5,594,000,000	$ 5,879,000,000
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
Term of facility	5 years
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
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	$ 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, days available for borrowing	90 days