Presentation of Financial Information - Earning Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Apr. 01, 2018	Apr. 02, 2017	Apr. 01, 2018	Apr. 02, 2017
BASIC
Net income	$ 12.3	$ 41.2	$ 60.2	$ 60.6
Weighted-average common shares outstanding (in shares)	117.4	114.7	117.2	114.4
Basic earnings (loss) per share (USD per share)	$ 0.10	$ 0.36	$ 0.51	$ 0.53
DILUTED
Net income	$ 12.3	$ 41.2	$ 60.2	$ 60.6
Weighted-average common shares outstanding (in shares)	117.4	114.7	117.2	114.4
Dilutive effect of stock awards	2.2	2.3	2.1	2.2
Weighted-average common shares outstanding on a diluted basis (in shares)	119.6	117.0	119.3	116.6
Diluted earnings per share (USD per share)	$ 0.10	$ 0.35	$ 0.50	$ 0.52
Stock awards excluded in computation of diluted EPS			0.2