GEOGRAPHIC INFORMATION - Revenue and Long-lived Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Total operating revenues	$ 5,716.4	$ 6,048.9	$ 6,894.5
Long-lived assets	599.5	561.1	518.1
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Total operating revenues	4,380.3	4,665.1	5,174.7
Long-lived assets	416.0	395.4	341.4
APAC
Revenues from External Customers and Long-Lived Assets [Line Items]
Total operating revenues	263.8	284.9	348.6
Long-lived assets	40.0	28.0	23.6
EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total operating revenues	1,072.3	1,098.9	1,371.2
Long-lived assets	$ 143.5	$ 137.7	$ 153.1