Discontinued Operations - Cash Flow Disclosures (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016
Operating activities:
Share-based compensation expense	$ 45.9	$ 41.2	$ 48.3
Depreciation	52.1	58.5	64.2
Amortization of intangible assets	20.6	18.4	15.6
Investing activities:
Purchases of property, plant & equipment	(47.7)	(59.1)	(80.4)
Acquisitions, net of cash acquired	(109.0)	(3.0)	(21.1)
Sale of available-for-sale securities	15.9	0.0	8.6
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Operating activities:
Share-based compensation expense		2.0	6.1
Depreciation		4.8	10.5
Amortization of intangible assets		1.8	5.5
Investing activities:
Purchases of property, plant & equipment		(6.4)	(28.9)
Acquisitions, net of cash acquired		0.0	(1.2)
Sale of available-for-sale securities		$ 0.0	$ 8.6
Varex Imaging \| Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net assets	$ 2.3

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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