Consolidated and Combined Statements of Comprehensive Income - USD ($) $ 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
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 75.2	$ 58.0	$ 98.8	$ 92.7	$ (352.4)	$ (24.1)	$ 11.6	$ 45.6	$ 324.7	$ (319.3)	$ 58.8
Other comprehensive income (loss), net of tax
Currency translation adjustments									(70.8)	(27.6)	1.5
Unrecognized gain (loss) on derivatives, net of tax (benefit) expense of $0.2, $0.2 and $-									0.4	0.5	(7.3)
Unrecognized gain (loss) on benefit plans, net of tax (benefit) expense of $(2.1), $(7.3) and $23.9									5.6	(15.7)	34.2
Total other comprehensive income (loss), net of tax									(64.8)	(42.8)	28.4
Comprehensive income (loss)									$ 259.9	$ (362.1)	$ 87.2