Stockholders' Equity and Noncontrolling Interests - Schedule of Accumulated Other Comprehensive Loss and Related Tax Effects (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	$ 1,521.9	$ 1,797.9	$ 1,783.0
Balance at end of period	1,588.7	1,521.9	1,797.9
Net Unrealized Gains (Losses) Defined Benefit Pension and Post-Retirement Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	(44.1)	(63.3)	(46.1)
Other comprehensive (loss) earnings before reclassifications	9.0	19.8	(23.4)
Amounts reclassified out of other comprehensive loss	1.7	3.4	2.4
Tax expense	(1.8)	(4.0)	3.8
Balance at end of period	(35.2)	(44.1)	(63.3)
Net Unrealized Gains (Losses) Cash Flow Hedging Instruments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	0.0	0.0	0.0
Other comprehensive (loss) earnings before reclassifications	(0.9)	0.0	(1.0)
Amounts reclassified out of other comprehensive loss	0.9	0.0	1.0
Tax expense	0.0	0.0	0.0
Balance at end of period	0.0	0.0	0.0
Net Unrealized Gains (Losses) Available-for- Sale Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	0.0	0.0	(0.1)
Other comprehensive (loss) earnings before reclassifications	0.0	0.0	(0.4)
Amounts reclassified out of other comprehensive loss	0.0	0.0	0.6
Tax expense	0.0	0.0	(0.1)
Balance at end of period	0.0	0.0	0.0
Cumulative Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	(24.7)	(37.5)	(40.3)
Other comprehensive (loss) earnings before reclassifications	(5.4)	12.8	2.8
Amounts reclassified out of other comprehensive loss	0.0	0.0	0.0
Tax expense	0.0	0.0	0.0
Balance at end of period	(30.1)	(24.7)	(37.5)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	(68.8)	(100.8)	(86.5)
Other comprehensive (loss) earnings before reclassifications	2.7	32.6	(22.0)
Amounts reclassified out of other comprehensive loss	2.6	3.4	4.0
Tax expense	(1.8)	(4.0)	3.7
Balance at end of period	$ (65.3)	$ (68.8)	$ (100.8)