Name:	jdsu_CarryingAmountOfLiabilityAndEquityComponentAbstract
Namespace Prefix:	jdsu_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

Debts and Letters of Credit (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended		0 Months Ended
	Dec. 27, 2014 item	Dec. 28, 2013	Dec. 27, 2014 item	Dec. 28, 2013	Aug. 21, 2013	Jun. 28, 2014
Debt details
Short-term debt	$ 0us-gaap_ShortTermBorrowings		$ 0us-gaap_ShortTermBorrowings			$ 0us-gaap_ShortTermBorrowings
Details of the Company's debt:
Effective interest rate (as a percent)	5.40%	5.40%	5.40%	5.40%
Effective interest rate and interest expense for the contractual interest and the accretion of debt discount:
Effective interest rate (as a percent)	5.40%	5.40%	5.40%	5.40%
Interest expense-contractual interest	1.0	1.0	2.0	1.4
Accretion of debt discount	6.3	6.0	12.5	8.6
Outstanding Letters of Credit
Number of standby letters of credit	12jdsu_LettersOfCreditNumberOutstanding		12jdsu_LettersOfCreditNumberOutstanding
Outstanding balance	32.3us-gaap_LineOfCredit		32.3us-gaap_LineOfCredit		0us-gaap_LineOfCredit
Revolving Credit Facility
Debt details
Revolving credit facility terminated					250.0
Details of the Company's debt:
Unamortized portion of debt issuance cost					1.3
0.625% Senior Convertible Debentures due 2033 ("notes")
Debt details
Conversion price of convertible debt (in dollars per share)	$ 18.83		$ 18.83
Amount outstanding	650.0		650.0			650.0
Details of the Company's debt:
Principal amount of 0.625% Senior Convertible Notes	650.0		650.0			650.0
Unamortized discount of liability component	(101.2)		(101.2)			(113.7)
Carrying amount of liability component	548.8		548.8		515.6	536.3
Carrying amount of equity component	134.4		134.4		134.4	134.4
Interest rate on senior convertible notes (as a percent)	0.625%		0.625%		0.625%
Aggregate principal amount of convertible debt					650.0
Proceeds from issuance of convertible notes after issuance costs					636.3
Discount rate used to calculate the carrying value of the liability component of the convertible debt (as a percent)					5.40%
Variable rate basis on which discount rate is based			5-year swap
Remaining term of convertible notes			3 years 7 months 6 days
Deferred finance costs					13.7
Liability component, debt issuance cost					10.9
Equity component, debt issuance cost					2.8
Fair market value of convertible debt	685.5		685.5			653.0
0.625% Senior Convertible Debentures due 2033 ("notes") \| Other non-current assets
Details of the Company's debt:
Unamortized portion of debt issuance cost	$ 8.2		$ 8.2