Revenue - Disaggregation of Revenues by Geographic Region (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2023	Oct. 02, 2022	Oct. 01, 2023	Oct. 02, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 1,118.0	$ 1,167.9	$ 3,603.5	$ 3,731.6
Americas
Disaggregation of Revenue [Line Items]
Revenue	891.3	943.5	2,925.5	2,986.4
Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenue	10.9	10.3	32.9	32.6
Science, Engineering & Technology
Disaggregation of Revenue [Line Items]
Revenue	295.7	321.3	903.5	962.7
Science, Engineering & Technology | Americas
Disaggregation of Revenue [Line Items]
Revenue	292.0	317.2	891.4	951.4
Science, Engineering & Technology | Europe
Disaggregation of Revenue [Line Items]
Revenue	3.7	4.1	12.1	11.3
Outsourcing & Consulting
Disaggregation of Revenue [Line Items]
Revenue	114.1	118.5	342.4	352.0
Outsourcing & Consulting | Americas
Disaggregation of Revenue [Line Items]
Revenue	94.1	103.1	281.2	302.5
Outsourcing & Consulting | Europe
Disaggregation of Revenue [Line Items]
Revenue	9.1	5.1	28.3	16.9
Outsourcing & Consulting | Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenue	10.9	10.3	32.9	32.6
International
Disaggregation of Revenue [Line Items]
Revenue	220.6	215.5	657.5	715.9
International | Americas
Disaggregation of Revenue [Line Items]
Revenue	17.6	10.6	52.8	31.5
International | Europe
Disaggregation of Revenue [Line Items]
Revenue	$ 203.0	$ 204.9	$ 604.7	$ 684.4