XML 131 R116.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Hedging Activities - Narrative (Details) € in Millions, £ in Millions | 12 Months Ended |
--- | --- | ---
Mar. 31, 2018 USD ($) | Mar. 31, 2017 USD ($) | Mar. 31, 2016 USD ($) | Mar. 31, 2018 EUR (€) | Mar. 31, 2018 USD ($) | Mar. 31, 2018 GBP (£)
Derivative [Line Items] |  |  |  |  |  |
Total debt outstanding |  | $ 8,362,000,000 |  |  | $ 7,880,000,000 |
Losses from net investment hedges | $ 268,000,000 | 13,000,000 |  |  |  |
(Losses) gains recorded in other comprehensive income | (30,000,000) | (19,000,000) | $ 9,000,000 |  |  |
Derivatives Designated for Hedge Accounting |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
(Losses) gains recorded in other comprehensive income | (30,000,000) | (19,000,000) | 9,000,000 |  |  |
Forward Contracts | Derivatives Designated for Hedge Accounting |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative, notional amount |  | 243,000,000 |  |  | 162,000,000 |
Foreign Exchange Contract | Derivatives Not Designated for Hedge Accounting |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Net gains on derivatives | 0 | 5,000,000 | $ 60,000,000 |  |  |
Currency Swap | Derivatives Designated for Hedge Accounting |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative, notional amount |  | 2,663,000,000 |  |  | 3,412,000,000 |
Euro Denominated Notes | Notes |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Total debt outstanding | € |  |  |  | € 1,950 |  |
British Pound Sterling Denominated Notes | Notes |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Total debt outstanding | £ |  |  |  |  |  | £ 450
Canada, Dollars | Foreign Exchange Contract | Derivatives Not Designated for Hedge Accounting |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative, notional amount |  | 173,000,000 |  |  |  |
United Kingdom, Pounds | Foreign Exchange Contract | Derivatives Not Designated for Hedge Accounting |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative, notional amount |  | $ 62,000,000 |  |  | $ 29,000,000 |
Net Investment Hedging |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Losses recorded in other comprehensive income | $ 7,000,000 |  |  |  |  |
Net Investment Hedging | Cross Currency Swap |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative, notional amount | £ |  |  |  |  |  | £ 432

X
- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
Name: | invest_DerivativeNotionalAmount
Namespace Prefix: | invest_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5618551-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
Name: | us-gaap_DerivativeGainLossOnDerivativeNet
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_DerivativeLineItems
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/presentationRef -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=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -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 3: http://www.xbrl.org/2003/role/presentationRef -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 after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669646-108580 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax
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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 20 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=64808268&loc=d3e32211-110900 + Details
Name: | us-gaap_TranslationAdjustmentForNetInvestmentHedgeIncreaseDecreaseGrossOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Current period adjustment in other comprehensive income reflecting gains or losses on foreign currency transactions that are designated as, and are effective as, hedges of a net investment in a foreign entity, net of tax effect. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 20 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=64808268&loc=d3e32211-110900 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
Name: | us-gaap_TranslationAdjustmentForNetInvestmentHedgeIncreaseDecreaseNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForwardContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CurrencySwapMember
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_CurrencyAxis=currency_CAD
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CurrencyAxis=currency_GBP
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_DerivativeInstrumentRiskAxis=mck_CrossCurrencySwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |