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Business Combinations - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions						3 Months Ended								6 Months Ended	12 Months Ended
	Oct. 01, 2018	Jul. 31, 2018	Dec. 11, 2017	Apr. 07, 2017	Mar. 22, 2017	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2016	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Sep. 24, 2016
Business Acquisition [Line Items]
Goodwill impairment								$ 685.7							$ 685.7	$ 0.0	$ 0.0
Revenues						$ 813.5	$ 824.0	789.3	$ 791.1	$ 0.8	$ 0.8	$ 0.7	$ 0.7		3,217.9	3,058.8	2,832.7
Pre-tax loss															237.9	(1,370.2)	$ (548.6)
Goodwill						2,533.2				3,171.2				$ 3,171.2	2,533.2	$ 3,171.2
Cynosure
Business Acquisition [Line Items]
Purchase price (in dollars per share)					$ 66.00
Total purchase price					$ 1,660.0
Transaction costs					18.8
Intangible assets												$ 994.0
Goodwill impairment								685.7
Revenues														207.5
Pre-tax loss														$ 96.4
Goodwill					685.7
Property, plant and equipment					44.1
Cynosure \| In-process research and development
Business Acquisition [Line Items]
Intangible assets					107.0
Estimated costs to complete					$ 18.0
Cynosure \| Developed technology
Business Acquisition [Line Items]
Project fair value										$ 61.0
Impairment charge								$ 46.0
Weighted average period					11 years 9 months 18 days
Cynosure \| Distribution agreement
Business Acquisition [Line Items]
Weighted average period					8 years
Cynosure \| Customer relationships
Business Acquisition [Line Items]
Weighted average period					7 years 8 months 12 days
Cynosure \| Trade names
Business Acquisition [Line Items]
Weighted average period					8 years 10 months 24 days
Cynosure \| Minimum \| Other intangible assets
Business Acquisition [Line Items]
Discount rate (as a percent)					11.00%
Cynosure \| Minimum \| In-process research and development
Business Acquisition [Line Items]
Discount rate (as a percent)					14.00%
Cynosure \| Maximum \| Other intangible assets
Business Acquisition [Line Items]
Discount rate (as a percent)					12.00%
Cynosure \| Maximum \| In-process research and development
Business Acquisition [Line Items]
Discount rate (as a percent)					22.00%
Medicor Medical Supply
Business Acquisition [Line Items]
Cash paid				$ 19.0
Intangible assets				$ 5.4							$ 5.4
Weighted average period				7 years 8 months 12 days
Acquisition price adjustment				$ 2.0
Purchase price withheld				1.9
Goodwill				8.9
Property, plant and equipment				$ 4.7
Emsor
Business Acquisition [Line Items]
Total purchase price			$ 16.3
Intangible assets			4.6
Purchase price withheld			$ 0.5			4.9									4.9
Payment period for contingent consideration			18 months
Goodwill			$ 5.7
Property, plant and equipment			$ 6.0
Faxitron
Business Acquisition [Line Items]
Total purchase price		$ 89.0
Intangible assets						53.4									53.4
Purchase price withheld		$ 11.7				$ 2.9									$ 2.9
Payment period for contingent consideration		1 year
Goodwill		$ 41.6
Faxitron \| Customer relationships
Business Acquisition [Line Items]
Weighted average period		9 years
Faxitron \| Trade names
Business Acquisition [Line Items]
Weighted average period		7 years
Faxitron \| Minimum \| In-process research and development
Business Acquisition [Line Items]
Discount rate (as a percent)		17.00%
Faxitron \| Maximum \| In-process research and development
Business Acquisition [Line Items]
Discount rate (as a percent)		19.00%
Subsequent Event \| Focal
Business Acquisition [Line Items]
Total purchase price	$ 125.0
Cash paid	$ 108.0