Consolidation Less Than Wholly Owned Subsidiary Parent Ownership Interest Changes Increase In Paid In Capital.

No definition available.

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Namespace Prefix:	mck_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

Consolidation Less Than Wholly Owned Subsidiary Parent Ownership Interest Changes Purchase Of Interest By Parent Common Shares

+ References

No definition available.

+ Details

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Namespace Prefix:	mck_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Consolidation, Less Than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Purchase Of Interest By Parent, Consideration Paid

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Consolidation Less Than Wholly Owned Subsidiary Parent Ownership Interest Changes Purchase Of Interest By Parent Percent

+ References

No definition available.

+ Details

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Namespace Prefix:	mck_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the total net income attributable to the parent for the period and the effect of net changes during the period impacting the parent's ownership interest in a subsidiary as it relates to the total (consolidated) equity attributable to the parent. The changes to the parent's ownership interest in a subsidiary represented by this element did not result in a deconsolidation of the subsidiary from the consolidated financial statements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

-Paragraph 4M

-URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591554-111686

+ Details

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

- Definition

Represents the purchase by the parent of an additional equity interest in a subsidiary during the period, thereby effecting a change in total (consolidated) equity attributable to the parent. The purchase of the additional equity interest represented by this element increases the parent's controlling interest in the subsidiary.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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- Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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Noncontrolling Interests (Ownership Changes) (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Mar. 31, 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
NCI change from shares acquired		$ (60)
NCI shares acquired, change in APIC	0	(3)
NCI shares acquired, change in parent net income and transfers to NCI	472	1,341
Celesio [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
NCI ownership interest, parent			75.40%
NCI shares acquired, cash paid		32
NCI shares acquired		1
NCI shares acquired, change in ownership percentage		0.50%
NCI change from shares acquired		$ (35)
Oncoprod [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
NCI ownership interest, parent			60.00%
NCI shares acquired, change in ownership percentage		40.00%