Convertible Senior Notes (Note Hedges) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Jun. 30, 2012
Debt Disclosure [Abstract]
Aggregate amount of hedge		$ 58.2invest_DerivativeNotionalAmount
Shares exercisable upon conversion		9.8mdco_SharesExercisableUponConversion
Fair Value Hedges, Net	$ 56.2us-gaap_FairValueHedgesAtFairValueNet

Net fair value of all derivative instruments designated as fair value hedging instruments.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

Name:	us-gaap_FairValueHedgesAtFairValueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant