SEGMENT AND GEOGRAPHIC INFORMATION - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total revenue	$ 12,390.9	$ 9,646.0	$ 7,961.0
Costs and Expenses	11,463.9	9,023.4	7,519.4
ATS
Segment Reporting Information [Line Items]
Total revenue	3,202.4	3,155.5	3,319.8
Cost of sales	2,876.1	2,894.9	3,044.3
Other segment costs	$ 157.2	$ 116.5	$ 120.5
ATS \| Revenue from Contract with Customer, Segment Benchmark \| Segment Concentration Risk
Segment Reporting Information [Line Items]
% of Total	26.00%	33.00%	42.00%
CCS
Segment Reporting Information [Line Items]
Total revenue	$ 9,188.5	$ 6,490.5	$ 4,641.2
Cost of sales	8,099.8	5,732.1	4,136.4
Other segment costs	$ 330.8	$ 279.9	$ 218.2
CCS \| Revenue from Contract with Customer, Segment Benchmark \| Segment Concentration Risk
Segment Reporting Information [Line Items]
% of Total	74.00%	67.00%	58.00%
CCS \| CCS, Communication Segment
Segment Reporting Information [Line Items]
Total revenue	$ 7,126.4	$ 3,946.7	$ 2,675.6
CCS \| CCS, Communication Segment \| Revenue from Contract with Customer, Segment Benchmark \| Segment Concentration Risk
Segment Reporting Information [Line Items]
% of Total	57.00%	41.00%	33.00%
CCS \| CCS, Enterprise Segment
Segment Reporting Information [Line Items]
Total revenue	$ 2,062.1	$ 2,543.8	$ 1,965.6
CCS \| CCS, Enterprise Segment \| Revenue from Contract with Customer, Segment Benchmark \| Segment Concentration Risk
Segment Reporting Information [Line Items]
% of Total	17.00%	26.00%	25.00%