SEGMENT AND CUSTOMER REPORTING - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Total revenue	$ 3,194.0	$ 2,499.5	$ 8,736.0	$ 7,100.3
Total Segment Costs	2,951.8	2,330.7	8,091.3	6,651.3
ATS
Segment Reporting Information [Line Items]
Total revenue	781.0	814.1	2,407.3	2,349.7
Cost of sales	698.0	746.1	2,150.6	2,148.2
Other segment costs	$ 40.2	$ 27.9	$ 129.7	$ 94.4
ATS | Revenue from Contract with Customer, Segment Benchmark | Segment Concentration Risk
Segment Reporting Information [Line Items]
% of total	24.00%	33.00%	28.00%	33.00%
CCS
Segment Reporting Information [Line Items]
Total revenue	$ 2,413.0	$ 1,685.4	$ 6,328.7	$ 4,750.6
Cost of sales	2,121.6	1,484.8	5,581.8	4,212.9
Other segment costs	$ 92.0	$ 71.9	$ 229.2	$ 195.8
CCS | Revenue from Contract with Customer, Segment Benchmark | Segment Concentration Risk
Segment Reporting Information [Line Items]
% of total	76.00%	67.00%	72.00%	67.00%
CCS | CCS, Communication Segment
Segment Reporting Information [Line Items]
Total revenue	$ 1,942.9	$ 1,067.3	$ 5,011.8	$ 2,766.7
CCS | CCS, Communication Segment | Revenue from Contract with Customer, Segment Benchmark | Segment Concentration Risk
Segment Reporting Information [Line Items]
% of total	61.00%	42.00%	57.00%	39.00%
CCS | CCS, Enterprise Segment
Segment Reporting Information [Line Items]
Total revenue	$ 470.1	$ 618.1	$ 1,316.9	$ 1,983.9
CCS | CCS, Enterprise Segment | Revenue from Contract with Customer, Segment Benchmark | Segment Concentration Risk
Segment Reporting Information [Line Items]
% of total	15.00%	25.00%	15.00%	28.00%