Document And Entity Information - USD ($) $ in Billions	12 Months Ended
	Jun. 30, 2015	Sep. 17, 2015	Dec. 31, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Entity Registrant Name	Zayo Group Holdings, Inc.
Entity Central Index Key	0001608249
Current Fiscal Year End Date	--06-30
Entity Filer Category	Non-accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	Yes
Entity Current Reporting Status	Yes
Entity Public Float			$ 7.3
Entity Common Stock, Shares Outstanding		243,008,679