Business Segments and Geographic Information - Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Sep. 28, 2019
Segment Reporting Information [Line Items]
Total revenues	$ 822.9	$ 852.4	$ 2,429.5	$ 2,501.4
Income (loss) from operations	191.0	145.3	472.2	(37.3)
Depreciation and amortization	93.6	113.3	281.7	349.7
Capital expenditures	35.0	25.8	98.0	77.7
Identifiable assets	6,803.1		6,803.1		$ 6,442.1
Diagnostics
Segment Reporting Information [Line Items]
Total revenues	532.2	305.4	1,163.2	898.6
Income (loss) from operations	233.9	45.7	340.7	120.1
Depreciation and amortization	59.4	61.6	177.8	184.9
Capital expenditures	28.4	14.2	63.7	44.7
Identifiable assets	2,169.0		2,169.0		2,276.6
Breast Health
Segment Reporting Information [Line Items]
Total revenues	224.0	325.4	862.8	971.6
Income (loss) from operations	(11.1)	97.5	158.6	294.3
Depreciation and amortization	13.0	9.3	36.2	27.5
Capital expenditures	3.0	3.0	17.5	9.7
Identifiable assets	1,225.8		1,225.8		1,127.8
Medical Aesthetics
Segment Reporting Information [Line Items]
Total revenues	0.0	85.0	65.3	238.6
Income (loss) from operations	(1.0)	(18.6)	(54.3)	(517.6)
Depreciation and amortization	0.0	20.4	4.1	71.0
Capital expenditures	0.0	1.2	1.4	5.7
Identifiable assets	0.0		0.0		159.3
GYN Surgical
Segment Reporting Information [Line Items]
Total revenues	51.5	112.2	275.9	322.8
Income (loss) from operations	(23.4)	22.5	32.0	70.0
Depreciation and amortization	21.0	21.9	63.1	65.8
Capital expenditures	2.4	4.3	12.9	10.9
Identifiable assets	1,271.6		1,271.6		1,328.6
Skeletal Health
Segment Reporting Information [Line Items]
Total revenues	15.2	24.4	62.3	69.8
Income (loss) from operations	(7.4)	(1.8)	(4.8)	(4.1)
Depreciation and amortization	0.2	0.1	0.5	0.5
Capital expenditures	0.1	0.4	0.3	1.0
Identifiable assets	32.4		32.4		27.3
Corporate
Segment Reporting Information [Line Items]
Capital expenditures	1.1	$ 2.7	2.2	$ 5.7
Identifiable assets	$ 2,104.3		$ 2,104.3		$ 1,522.5