Earnings (Loss) per Share Schedule of Earnings per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Sep. 25, 2015		Jun. 26, 2015		Mar. 27, 2015		Dec. 26, 2014		Sep. 26, 2014		Jun. 27, 2014		Mar. 28, 2014		Dec. 27, 2013		Sep. 25, 2015	Sep. 26, 2014	Sep. 27, 2013
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ 90.0		$ 55.6		$ 75.2		$ 87.4		$ (173.5)		$ (29.0)		$ 20.2		$ 38.5		$ 308.2	$ (143.8)	$ 8.2
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic																	2.5	0.0	0.0
Income (Loss) From Continuing Operations Attributable To Common Stockholders																	305.7	(143.8)	8.2
Income (loss) from discontinued operations, net of income taxes	$ (14.8)		$ 2.4		$ 23.6		$ 5.3		$ (178.9)		$ 4.9		$ (8.6)		$ 7.1		16.5	(175.5)	50.6
Income (Loss) From Discontinued Operations Attributable To Common Stockholders																	0.1	0.0	0.0
Net Income (Loss) Available to Common Stockholders, Basic																	16.4	(175.5)	50.6
Net Income (Loss) Available to Common Stockholders, Basic																	$ 322.1	$ (319.3)	$ 58.8
Weighted Average Number of Shares Outstanding, Basic																	115.8	64.9	57.7
Weighted Average Number of Shares Outstanding, Diluted																	1.4	0.0	0.1
Weighted Average Number of Shares Outstanding, Diluted																	117.2	64.9	57.8
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.77	[1]	$ 0.47	[1]	$ 0.64	[1]	$ 0.75	[1]	$ (2.04)	[1]	$ (0.50)	[1]	$ 0.35	[1]	$ 0.67	[1]	$ 2.64	$ (2.22)	$ 0.14
Earnings Per Share, Basic																	0.14	(2.70)	0.88
Earnings Per Share, Basic																	2.78	(4.92)	1.02
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.76	[1]	$ 0.47	[1]	$ 0.64	[1]	$ 0.74	[1]	$ (2.04)	[1]	$ (0.50)	[1]	$ 0.34	[1]	$ 0.66	[1]	2.61	(2.22)	0.14
Earnings Per Share, Diluted																	0.14	(2.70)	0.88
Earnings Per Share, Diluted																	$ 2.75	$ (4.92)	$ 1.02

[1] Quarterly and annual computations are prepared independently. Therefore, the sum of each quarter may not necessarily total the fiscal period amounts noted elsewhere within this Annual Report on Form 10-K.