Revenue - Revenue by Country (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2024	Dec. 31, 2023	Jan. 01, 2023
Disaggregation of Revenue [Line Items]
Revenue from services	$ 4,331.8	$ 4,835.7	$ 4,965.4
Total Americas Region
Disaggregation of Revenue [Line Items]
Revenue from services	4,234.2	3,928.3	3,998.6
United States
Disaggregation of Revenue [Line Items]
Revenue from services	3,876.9	3,555.8	3,671.5
Canada
Disaggregation of Revenue [Line Items]
Revenue from services	188.6	189.8	168.2
Puerto Rico
Disaggregation of Revenue [Line Items]
Revenue from services	108.0	107.0	112.4
Mexico
Disaggregation of Revenue [Line Items]
Revenue from services	60.7	75.7	46.5
Total Europe Region
Disaggregation of Revenue [Line Items]
Revenue from services	41.9	863.7	924.7
Switzerland
Disaggregation of Revenue [Line Items]
Revenue from services	4.0	224.2	222.8
France
Disaggregation of Revenue [Line Items]
Revenue from services	0.4	194.4	199.4
Portugal
Disaggregation of Revenue [Line Items]
Revenue from services	0.0	189.4	169.5
Italy
Disaggregation of Revenue [Line Items]
Revenue from services	0.0	63.9	69.3
Russia
Disaggregation of Revenue [Line Items]
Revenue from services	0.0	0.0	63.4
Other
Disaggregation of Revenue [Line Items]
Revenue from services	37.5	191.8	200.3
Total Asia-Pacific Region
Disaggregation of Revenue [Line Items]
Revenue from services	$ 55.7	$ 43.7	$ 42.1