Consolidated and Combined Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Sep. 25, 2015	Jun. 26, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 115.0	$ 199.3	$ 118.3	$ 211.1	$ 75.2	$ 58.0	$ 98.8	$ 92.7	$ 643.7	$ 324.7	$ (319.3)
Other comprehensive (loss), net of tax
Currency translation adjustments									(58.6)	(70.8)	(27.6)
Unrecognized gain on derivatives, net of tax expense of $0.2, $0.2 and $0.2									0.5	0.4	0.5
Unrecognized gain (loss) on benefit plans, net of tax (benefit) expense of $(15.0), $(2.1) and $(7.3)									(28.4)	5.6	(15.7)
Total other comprehensive (loss), net of tax									(86.5)	(64.8)	(42.8)
Comprehensive income (loss)									$ 557.2	$ 259.9	$ (362.1)