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Business Segments and Geographic Information - Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 30, 2017	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Total revenue	$ 865.8	$ 852.4	$ 818.4	$ 830.7	$ 813.5	$ 824.0	$ 789.3	$ 791.1	$ 3,367.3	$ 3,217.9	$ 3,058.8
Operating income									(123.8)	(237.9)	1,370.2
Depreciation and amortization									463.1	480.3	449.2
Capital expenditures									109.1	105.6	107.6
Identifiable assets	6,442.1				7,230.9				6,442.1	7,230.9	7,979.6
Corporate
Segment Reporting Information [Line Items]
Capital expenditures									7.7	7.3	21.0
Identifiable assets	1,522.5				1,457.1				1,522.5	1,457.1	1,262.7
Diagnostics
Segment Reporting Information [Line Items]
Total revenue									1,205.5	1,147.4	1,197.1
Operating income									163.1	145.5	1,054.2
Depreciation and amortization									246.6	257.3	278.9
Capital expenditures									59.2	57.7	50.9
Identifiable assets	2,276.6				2,442.9				2,276.6	2,442.9	2,621.6
Breast Health
Segment Reporting Information [Line Items]
Total revenue									1,314.2	1,218.2	1,138.3
Operating income									399.3	399.7	373.4
Depreciation and amortization									36.8	22.7	19.7
Capital expenditures									18.3	14.8	12.0
Identifiable assets	1,127.8				972.4				1,127.8	972.4	824.0
Medical Aesthetics
Segment Reporting Information [Line Items]
Total revenue									315.6	339.1	207.5
Operating income									(781.2)	(844.7)	(115.9)
Depreciation and amortization									91.4	108.1	54.2
Capital expenditures									7.0	9.4	7.3
Identifiable assets	159.3				913.3				159.3	913.3	1,751.2
GYN Surgical
Segment Reporting Information [Line Items]
Total revenue									437.2	422.0	427.1
Operating income									99.2	58.3	65.0
Depreciation and amortization									87.7	91.6	95.7
Capital expenditures									15.7	13.1	15.2
Identifiable assets	1,328.6				1,414.9				1,328.6	1,414.9	1,494.6
Skeletal Health
Segment Reporting Information [Line Items]
Total revenue									94.8	91.2	88.8
Operating income									(4.2)	3.3	(6.5)
Depreciation and amortization									0.6	0.6	0.7
Capital expenditures									1.2	3.3	1.2
Identifiable assets	$ 27.3				$ 30.3				$ 27.3	$ 30.3	$ 25.5