Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 29, 2018	Dec. 30, 2017	May 29, 2018	Aug. 21, 2013
Numerator:
Income (loss) from continuing operations, net of taxes	$ 15.4	$ (1.1)	$ 0.1	$ (8.7)
Loss from discontinued operations, net of taxes	(2.4)	0.0	(2.4)	0.0
Net income (loss)	$ 13.0	$ (1.1)	$ (2.3)	$ (8.7)
Weighted-average number of common shares outstanding
Basic (in shares)	228.3	227.4	227.8	227.7
Effect of dilutive securities from stock-based benefit plans (in shares)	2.1	0.0	2.7	0.0
Diluted (in shares)	230.4	227.4	230.5	227.7
Net income (loss) per share - basic:
Continuing operations (in dollars per share)	$ 0.07	$ 0.00	$ 0.00	$ (0.04)
Discontinued operations (in dollars per share)	(0.01)	0.00	(0.01)	0.00
Net income (loss) per share - basic (in dollars per share)	0.06	0.00	(0.01)	(0.04)
Net income (loss) per share - diluted:
Continuing operations (in dollars per share)	0.07	0.00	0.00	(0.04)
Discontinued operations (in dollars per share)	(0.01)	0.00	(0.01)	0.00
Net income (loss) per share - diluted (in dollars per share)	$ 0.06	$ 0.00	$ (0.01)	$ (0.04)
Anti-dilutive securities excluded from computation of earnings per share
Total potentially dilutive securities (in shares)	0.3	9.3	0.8	9.4
2033 Notes | Convertible Notes
Convertible notes
Interest rate on senior convertible notes	0.625%		0.625%			0.625%
Conversion price of debt (in dollars per share)			$ 11.28
2024 Notes | Convertible Notes
Convertible notes
Interest rate on senior convertible notes	1.00%		1.00%
Conversion price of debt (in dollars per share)	$ 13.22
2023 Notes | Convertible Notes
Convertible notes
Interest rate on senior convertible notes	1.75%		1.75%		1.75%
Conversion price of debt (in dollars per share)			$ 13.94
Stock options and ESPP
Anti-dilutive securities excluded from computation of earnings per share
Total potentially dilutive securities (in shares)	0.1	1.6	0.1	1.6
Restricted Stock Units
Anti-dilutive securities excluded from computation of earnings per share
Total potentially dilutive securities (in shares)	0.2	7.7	0.7	7.8