Stockholders' Equity and Noncontrolling Interests - Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Oct. 02, 2015
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	$ 1,744.2	$ 1,726.3	$ 1,616.4
Net earnings (loss) attributable to noncontrolling interests	(0.7)	(0.4)	(0.5)
Balance at end of period	1,499.3	1,744.2	1,726.3
Stockholders' Equity Attributable to Redeemable Noncontrolling Interest
Balance at beginning of period	10.3	0.0
Net earnings (loss) attributable to noncontrolling interests	0.1	0.5
Reclassification of noncontrolling interests in MeVis to redeemable noncontrolling interests	0.0	10.4
Transfer of redeemable noncontrolling interests in MeVis to Varex	(10.3)	0.0
Other	(0.1)	(0.6)
Balance at end of period	0.0	10.3	0.0
Noncontrolling Interests
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period	3.7	14.7	0.0
Net earnings (loss) attributable to noncontrolling interests	0.6	(0.1)
Reclassification of noncontrolling interests in MeVis to redeemable noncontrolling interests	0.0	(10.4)
Transfer of redeemable noncontrolling interests in MeVis to Varex	0.0	0.0
Other	0.0	(0.5)
Balance at end of period	$ 4.3	$ 3.7	$ 14.7