CONSOLIDATED STATEMENTS OF COMPREHENSIVE EARNINGS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Oct. 02, 2015	Sep. 26, 2014
Statement of Comprehensive Income [Abstract]
Net gain/(loss) arising during the year, tax benefit/(expense)	$ 4.3	$ 0.9	$ 0.9
Prior service cost arising during the year, tax expense	(0.2)		(1.2)
Amortization of prior service cost included in net periodic benefit cost, tax benefit/(expense)	0.2	0.1	(0.1)
Amortization of net actuarial loss included in net periodic benefit cost, tax expense	(0.5)	(0.6)	(0.5)
Increase (decrease) in unrealized gain, tax benefit/(expense)	0.4	(0.8)	(1.4)
Reclassification adjustments, tax benefit/(expense)	(0.4)	1.4	0.5
Increase (decrease) in unrealized gain (loss), tax benefit	0.1	0.1	0.0
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, Tax	$ (0.2)	$ 0.0	$ 0.0