SEGMENT AND CUSTOMER REPORTING - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Segment Reporting [Line Items]
Total revenue	$ 4,698.6	$ 2,893.4	$ 8,745.6	$ 5,542.0
Total Segment Costs	4,312.3	2,678.7	8,034.1	5,139.5
CCS
Segment Reporting [Line Items]
Total revenue	3,810.3	2,074.3	7,051.3	3,915.7
Cost of sales	3,374.0	1,829.6	6,252.4	3,460.2
Other segment costs	$ 106.4	$ 73.5	$ 191.8	$ 137.2
CCS \| Revenue from Contract with Customer, Segment Benchmark \| Segment Concentration Risk
Segment Reporting [Line Items]
% of total	81.00%	72.00%	81.00%	71.00%
CCS \| CCS, Communication Segment
Segment Reporting [Line Items]
Total revenue	$ 2,653.2	$ 1,641.2	$ 5,063.8	$ 3,068.9
CCS \| CCS, Communication Segment \| Revenue from Contract with Customer, Segment Benchmark \| Segment Concentration Risk
Segment Reporting [Line Items]
% of total	56.00%	57.00%	58.00%	56.00%
CCS \| CCS, Enterprise Segment
Segment Reporting [Line Items]
Total revenue	$ 1,157.1	$ 433.1	$ 1,987.5	$ 846.8
CCS \| CCS, Enterprise Segment \| Revenue from Contract with Customer, Segment Benchmark \| Segment Concentration Risk
Segment Reporting [Line Items]
% of total	25.00%	15.00%	23.00%	15.00%
ATS
Segment Reporting [Line Items]
Total revenue	$ 888.3	$ 819.1	$ 1,694.3	$ 1,626.3
Cost of sales	785.9	726.1	1,496.2	1,452.6
Other segment costs	$ 46.0	$ 49.5	$ 93.7	$ 89.5
ATS \| Revenue from Contract with Customer, Segment Benchmark \| Segment Concentration Risk
Segment Reporting [Line Items]
% of total	19.00%	28.00%	19.00%	29.00%