SEGMENT AND CUSTOMER REPORTING - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Total revenue	$ 2,648.6	$ 2,208.9
Total Segment Costs	2,460.8	2,078.3
ATS
Segment Reporting Information [Line Items]
Total revenue	807.2	767.9
Cost of sales	726.5	701.2
Other segment costs	$ 40.0	$ 34.8
ATS | Revenue from Contract with Customer, Segment Benchmark | Segment Concentration Risk
Segment Reporting Information [Line Items]
% of Total	30.00%	35.00%
CCS
Segment Reporting Information [Line Items]
Total revenue	$ 1,841.4	$ 1,441.0
Cost of sales	1,630.6	1,289.5
Other segment costs	$ 63.7	$ 52.8
CCS | Revenue from Contract with Customer, Segment Benchmark | Segment Concentration Risk
Segment Reporting Information [Line Items]
% of Total	70.00%	65.00%
CCS | CCS, Communication Segment
Segment Reporting Information [Line Items]
Total revenue	$ 1,427.7	$ 764.2
CCS | CCS, Communication Segment | Revenue from Contract with Customer, Segment Benchmark | Segment Concentration Risk
Segment Reporting Information [Line Items]
% of Total	54.00%	34.00%
CCS | CCS, Enterprise Segment
Segment Reporting Information [Line Items]
Total revenue	$ 413.7	$ 676.8
CCS | CCS, Enterprise Segment | Revenue from Contract with Customer, Segment Benchmark | Segment Concentration Risk
Segment Reporting Information [Line Items]
% of Total	16.00%	31.00%