Description of Business and Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended			6 Months Ended		12 Months Ended
		Aug. 01, 2015	Dec. 26, 2015	Sep. 26, 2015	Dec. 27, 2014	Dec. 26, 2015	Dec. 27, 2014	Jun. 25, 2016	Jun. 27, 2015
Property, Plant and Equipment
Percentage of outstanding shares distributed		80.10%
Ownership percentage		19.90%
Fiscal period									364 days
Accretion expense of Series A preferred stock			$ 2.0		$ 0.0	$ 11.7	$ 0.0
Net income (loss) available to common stockholders			$ 0.6		$ (4.1)	$ (9.4)	$ 0.2
Net income (loss) attributable to common shareholders, basic (usd per share)	[1]		$ 0.01		$ (0.07)	$ (0.16)	$ 0.00
Net income (loss) attributable to common shareholders, diluted (usd per share)	[1]		$ 0.01		$ (0.07)	$ (0.16)	$ 0.00
Forecast
Property, Plant and Equipment
Fiscal period								371 days
Restatement adjustment
Property, Plant and Equipment
Accretion expense of Series A preferred stock				$ 2.0
Net income (loss) available to common stockholders			$ 2.0	(2.0)
Net income (loss) available to common stockholders, diluted			$ 2.0	$ (2.0)
Net income (loss) attributable to common shareholders, basic (usd per share)			$ 0.03	$ (0.03)
Net income (loss) attributable to common shareholders, diluted (usd per share)			$ 0.03	$ (0.03)
Increase in mezzanine equity			$ 2.0
Decrease in stockholders' equity			$ 2.0
Spin Off Transaction
Property, Plant and Equipment
Conversion ratio of prior shares of JDSU to Lumentum		0.2

[1] On August 1, 2015, JDS Uniphase Corporation (“JDSU”) distributed 47.1 million shares, or 80.1% of the outstanding shares of common stock of Lumentum Holdings Inc. (“we”, “our”, “Company” or “Lumentum”) to existing holders of JDSU common stock. JDSU was renamed Viavi Solutions Inc. (“Viavi”) and at the time of the distribution, retained 11.7 million shares, or 19.9% of Lumentum’s outstanding shares. Basic and diluted net income (loss) per share for the three and six months ended December 27, 2014 is calculated using the shares of Lumentum common stock outstanding on August 1, 2015, as if such shares were outstanding for the entire period.