Business Segments and Geographic Information - Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 25, 2021	Dec. 26, 2020	Sep. 25, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 1,471.1	$ 1,609.8
Income (loss) from operations	641.3	885.5
Depreciation and amortization	108.0	92.8
Capital expenditures	16.2	44.8
Identifiable assets	9,285.1		$ 8,919.9
Diagnostics
Segment Reporting Information [Line Items]
Total revenues	950.4	1,128.2
Income (loss) from operations	531.8	784.5
Depreciation and amortization	69.4	56.3
Capital expenditures	9.7	38.3
Identifiable assets	3,272.1		3,348.8
Breast Health
Segment Reporting Information [Line Items]
Total revenues	359.3	332.7
Income (loss) from operations	81.7	86.3
Depreciation and amortization	15.5	13.1
Capital expenditures	4.2	2.9
Identifiable assets	1,218.7		1,233.9
GYN Surgical
Segment Reporting Information [Line Items]
Total revenues	134.3	124.0
Income (loss) from operations	26.6	13.7
Depreciation and amortization	22.9	23.2
Capital expenditures	2.1	3.3
Identifiable assets	1,517.1		1,369.7
Skeletal Health
Segment Reporting Information [Line Items]
Total revenues	27.1	24.9
Income (loss) from operations	1.2	1.0
Depreciation and amortization	0.2	0.2
Capital expenditures	0.1	0.0
Identifiable assets	38.1		31.9
Corporate
Segment Reporting Information [Line Items]
Capital expenditures	0.1	$ 0.3
Identifiable assets	$ 3,239.1		$ 2,935.6