Earnings Per Share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Jun. 27, 2020	Mar. 28, 2020	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 27, 2020	Jun. 29, 2019	Jun. 30, 2018
Numerator:
Income (loss) from continuing operations, net of taxes	$ 26.7	$ (32.8)	$ 28.0	$ 6.8	$ 12.5	$ (4.8)	$ 15.4	$ (15.3)	$ 28.7	$ 7.8	$ (48.6)
Loss from discontinued operations, net of taxes	0.0	0.0	0.0	0.0	0.0	0.0	(2.4)	0.0	0.0	(2.4)	0.0
Net income (loss)	$ 26.7	$ (32.8)	$ 28.0	$ 6.8	$ 12.5	$ (4.8)	$ 13.0	$ (15.3)	$ 28.7	$ 5.4	$ (48.6)
Weighted-average shares outstanding:
Basic (in shares)	228.1	230.0	230.0	229.4	228.7	228.3	228.3	227.2	229.4	228.1	227.1
Shares issuable assuming conversion of convertible notes (in shares)									1.2	0.0	0.0
Effect of dilutive securities from stock-based benefit plans (in shares)									3.1	3.1	0.0
Diluted (in shares)	230.3	230.0	238.3	236.4	232.5	228.3	230.4	227.2	233.7	231.2	227.1
Net income (loss) per share from - basic:
Continuing operations (usd per share)	$ 0.12	$ (0.14)	$ 0.12	$ 0.03	$ 0.05	$ (0.02)	$ 0.07	$ (0.07)	$ 0.13	$ 0.03	$ (0.21)
Discontinued operations (usd per share)	0	0	0	0	0	0	(0.01)	0	0	(0.01)	0
Net income (loss) (usd per share)	0.12	(0.14)	0.12	0.03	0.05	(0.02)	0.06	(0.07)	0.13	0.02	(0.21)
Net income (loss) per share from - diluted:
Continuing operations (usd per share)	0.12	(0.14)	0.12	0.03	0.05	(0.02)	0.07	(0.07)	0.12	0.03	(0.21)
Discontinued operations (usd per share)	0	0	0	0	0	0	(0.01)	0	0	(0.01)	0
Net income (loss) (usd per share)	$ 0.12	$ (0.14)	$ 0.12	$ 0.03	$ 0.05	$ (0.02)	$ 0.06	$ (0.07)	$ 0.12	$ 0.02	$ (0.21)