Property, plant and equipment, net - Schedule of Property, Plant, Equipment and Accumulated Depreciation Balances. (Details) - USD ($) $ in Millions	Jan. 02, 2022	Jan. 03, 2021
Property Plant And Equipment [Line Items]
Total property, plant and equipment	$ 1,902.4	$ 1,800.4
Less: Accumulated depreciation	(1,111.0)	(968.4)
Net property, plant and equipment	791.4	832.0
Land and leasehold improvements
Property Plant And Equipment [Line Items]
Total property, plant and equipment	23.3	23.3
Building and Building Improvements
Property Plant And Equipment [Line Items]
Total property, plant and equipment	245.9	246.8
Machinery and Equipment
Property Plant And Equipment [Line Items]
Total property, plant and equipment	475.1	458.3
Computer software and development costs
Property Plant And Equipment [Line Items]
Total property, plant and equipment	294.0	273.6
Customer Leased Instruments
Property Plant And Equipment [Line Items]
Total property, plant and equipment	775.9	727.3
Construction in Progress
Property Plant And Equipment [Line Items]
Total property, plant and equipment	$ 88.3	$ 71.1