Presentation of Financial Information - Earning Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Jul. 02, 2017	Jul. 03, 2016	Jul. 02, 2017	Jul. 03, 2016
BASIC
Net income (loss)	$ 13.6	$ 115.2	$ 74.3	$ (73.1)
Weighted-average common shares outstanding (in shares)	115,000,000	112,100,000	114,700,000	105,300,000
Basic earnings (loss) per share (USD per share)	$ 0.12	$ 1.03	$ 0.65	$ (0.69)
DILUTED
Net income (loss)	$ 13.6	$ 115.2	$ 74.3	$ (73.1)
Weighted-average common shares outstanding (in shares)	115,000,000	112,100,000	114,700,000	105,300,000
Dilutive effect of stock awards	2,200,000	2,500,000	2,100,000	0
Weighted-average common shares outstanding on a diluted basis (in shares)	117,200,000	114,600,000	116,800,000	105,300,000
Diluted earnings per share (USD per share)	$ 0.12	$ 1.00	$ 0.64	$ (0.69)
Stock awards excluded in computation of diluted EPS		200,000	0