XML 11 R69.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Stockholders' Equity - Schedule of Other Comprehensive Income (Loss), Net of Tax (Details) € in Millions, £ in Millions, $ in Millions | 3 Months Ended | 9 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2019 EUR (€) | Dec. 31, 2019 GBP (£) | Sep. 30, 2019 GBP (£) | Mar. 31, 2019 USD ($) | Mar. 31, 2019 EUR (€) | Mar. 31, 2019 GBP (£) | Dec. 31, 2018 EUR (€) | Dec. 31, 2018 GBP (£)
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | $ 45 | $ (76) | $ 86 | $ (169) |  |  |  |  |  |  |  |
Reclassified to income statement, net of income tax expense | 6 | 1 | 98 | 5 |  |  |  |  |  |  |  |
Other Comprehensive Income (Loss), Net of Tax | 51 | (75) | 184 | (164) |  |  |  |  |  |  |  |
Foreign currency translation adjustments arising during period, tax | 0 | 0 | 0 | 0 |  |  |  |  |  |  |  |
Reclassified to income statement, tax | 0 | 0 | 0 | 0 |  |  |  |  |  |  |  |
Unrealized gains on cash flow hedges arising during period, tax | 3 | (5) | (7) | (5) |  |  |  |  |  |  |  |
Net actuarial loss and prior service cost arising during the period, tax | 0 | 0 | 1 | 0 |  |  |  |  |  |  |  |
Amortization of actuarial (gain) loss and prior service costs, tax | 0 | 1 | 0 | (1) |  |  |  |  |  |  |  |
Foreign currency translation adjustments and other, tax | 0 | 0 | 0 | 0 |  |  |  |  |  |  |  |
Long-term debt outstanding | 7,700 |  | 7,700 |  |  |  |  | $ 7,600 |  |  |  |
Net actuarial gain (losses) attributable to redeemable noncontrolling interest | (2) | 0 | (1) | 2 |  |  |  |  |  |  |  |
Foreign Currency Translation Adjustments, Net of Tax |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | 101 | (188) | 57 | (456) |  |  |  |  |  |  |  |
Reclassified to income statement, net of income tax expense | 0 | 0 | 0 | 0 |  |  |  |  |  |  |  |
Other Comprehensive Income (Loss), Net of Tax | 101 | (188) | 57 | (456) |  |  |  |  |  |  |  |
Translation gain (loss) attributable to redeemable noncontrolling interest | 12 | (11) | (1) | (57) |  |  |  |  |  |  |  |
Unrealized Gains (Losses) on Net Investment Hedges, Net of Tax |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | (58) | 75 | (2) | 240 |  |  |  |  |  |  |  |
Reclassified to income statement, net of income tax expense | 0 | 0 | 0 | 0 |  |  |  |  |  |  |  |
Other Comprehensive Income (Loss), Net of Tax | (58) | 75 | (2) | 240 |  |  |  |  |  |  |  |
Unrealized gains (losses) on net investment hedges arising during period, tax | 21 | (27) | 1 | (85) |  |  |  |  |  |  |  |
Reclassified to income statement, tax | 0 | 0 | 0 | 0 |  |  |  |  |  |  |  |
Unrealized Gains (Losses) on Cash Flow Hedges, Net of Tax |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | 8 | 35 | 33 | 37 |  |  |  |  |  |  |  |
Reclassified to income statement, net of income tax expense | 0 | 0 | 0 | 0 |  |  |  |  |  |  |  |
Other Comprehensive Income (Loss), Net of Tax | 8 | 35 | 33 | 37 |  |  |  |  |  |  |  |
Reclassified to income statement, tax | 0 | 0 | 0 | 0 |  |  |  |  |  |  |  |
Accumulated Defined Benefit Plans Adjustment, Net Prior Service and Net Gain (Loss) Including Portion Attributable to Noncontrolling Interest |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | 0 | 0 | (3) | 0 |  |  |  |  |  |  |  |
Accumulated Defined Benefit Plans Adjustment, Amortization of Actuarial Loss, Prior Service Cost and Transition Obligation, Including Portion Attributable to Noncontrolling Interest |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | (2) | 1 | 0 | 5 |  |  |  |  |  |  |  |
Accumulated Defined Benefit Plans, Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Other comprehensive income (loss) before reclassifications | (6) | 2 | 1 | 10 |  |  |  |  |  |  |  |
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Reclassified to income statement, net of income tax expense | 8 | 0 | 98 | 0 |  |  |  |  |  |  |  |
Other Comprehensive Income (Loss), Net of Tax | 0 | 3 | 96 | 15 |  |  |  |  |  |  |  |
Reclassified to income statement, tax | 3 | 0 | 35 | 0 |  |  |  |  |  |  |  |
Euro Denominated Notes | Term Loan |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt outstanding | € |  |  |  |  | € 250 |  |  |  |  |  | € 1,950 |
British Pound Sterling Denominated Notes | Term Loan |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt outstanding | £ |  |  |  |  |  | £ 450 | £ 450 |  |  | £ 450 |  | £ 450
Net Investment Hedging | Euro Denominated Notes | Term Loan |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt outstanding | € |  |  |  |  | € 1,700 |  |  |  | € 1,950 |  |  |
Derivatives designated for hedge accounting |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) from net investment hedges recorded within other comprehensive income | (59) | 39 | (8) | 223 |  |  |  |  |  |  |  |
Derivatives designated for hedge accounting | Net Investment Hedging |  |  |  |  |  |  |  |  |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Derivatives used in net investment hedge, gains (loss) gross | $ (20) | $ 63 | $ (11) | $ 102 |  |  |  |  |  |  |  |

X
- Definition Other Comprehensive Income (Loss) Defined Benefit Plans Net Unamortized Gain Loss Attributable to Redeemable Noncontrolling Interest Arising During Period Net Of Tax + References No definition available. + Details
Name: | mck_OtherComprehensiveIncomeLossDefinedBenefitPlansNetUnamortizedGainLossAttributabletoRedeemableNoncontrollingInterestArisingDuringPeriodNetOfTax
Namespace Prefix: | mck_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Other Comprehensive Income (Loss) Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Redeemable Noncontrolling Interest + References No definition available. + Details
Name: | mck_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToRedeemableNoncontrollingInterest
Namespace Prefix: | mck_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Other Comprehensive Income Translation Impact On Pension Plans, Tax + References No definition available. + Details
Name: | mck_OtherComprehensiveIncomeTranslationImpactOnPensionPlansTax
Namespace Prefix: | mck_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_AccumulatedOtherComprehensiveIncomeLossLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of tax expense (benefit), before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 20 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=118261656&loc=d3e32211-110900 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580 + Details
Name: | us-gaap_OtherComprehensiveIncomeForeignCurrencyTranslationGainLossArisingDuringPeriodTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of tax (expense) benefit of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount after tax, before reclassification adjustments of other comprehensive income (loss). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 55 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=118951672&loc=d3e1436-108581 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of tax expense (benefit) allocated to other comprehensive income (loss) before reclassification adjustment from accumulated other comprehensive income (loss). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 11 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109238882&loc=d3e39076-109324 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, after reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for translation gain (loss) realized upon the sale or liquidation of an investment in a foreign entity and foreign currency hedges that are designated and qualified as hedging instruments for hedges of the foreign currency exposure of a net investment in a foreign operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 21 -URI http://asc.fasb.org/extlink&oid=118261656&loc=d3e32262-110900 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationReclassificationAdjustmentFromAOCIRealizedUponSaleOrLiquidationTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, before tax and reclassification, of gain (loss) from derivative designated and qualifying as net investment hedge. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4CCC -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109998896-113959 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossNetInvestmentHedgeGainLossBeforeReclassificationAndTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax and reclassification adjustments of other comprehensive income (loss). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 1A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669619-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 55 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=118951672&loc=d3e1436-108581 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 1B -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669625-108580 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of tax (expense) benefit for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 45 -Paragraph 19 -URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569616-111683 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax of reclassification adjustments of other comprehensive income (loss). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 17B -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL34724394-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 55 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=118951672&loc=d3e1436-108581 + Details
Name: | us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e640-108580 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 17A -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL34724391-108580 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 11 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109238882&loc=d3e39076-109324 + Details
Name: | us-gaap_ReclassificationFromAociCurrentPeriodTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, before tax, of increase (decrease) in the cumulative translation adjustment from gain (loss) on foreign currency derivatives that are designated as, and are effective as, economic hedges of a net investment in a foreign entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 20 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118261656&loc=d3e32211-110900 + Details
Name: | us-gaap_TranslationAdjustmentForNetInvestmentHedgeIncreaseDecreaseGrossOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedNetInvestmentGainLossIncludingPortionAttributableToNoncontrollingInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=mck_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceandNetGainLossIncludingPortionAttributabletoNoncontrollingInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=mck_AccumulatedDefinedBenefitPlansAdjustmentAmortizationofActuarialLossPriorServiceCostandTransitionObligationIncludingPortionAttributabletoNoncontrollingInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=mck_AccumulatedDefinedBenefitPlansForeignCurrencyAdjustmentIncludingPortionAttributabletoNoncontrollingInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mck_EuroDenominatedNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_LoansPayableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=mck_BritishPoundSterlingDenominatedNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_NetInvestmentHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |