LEASES - Lease expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lease expense
Operating lease cost	$ 41.1
Short-term lease cost	2.7
Variable lease cost	6.8
Total	$ 50.6
Lease expense		$ 47.5	$ 67.3
Remaining lease term - operating leases	11 years 6 months
Discount rate - operating leases	5.20%
Supplemental cash flow information related to leases was as follows:
Operating cash flows from operating leases	$ 46.6
Operating leases - Right-of-use assets obtained in exchange for lease obligations	$ 28.4