RECEIVABLES - Roll-forward of allowance for credit losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Contract assets
Allowance for credit losses at December 31, 2021	$ 1.1
Allowance for credit losses at March 31, 2022	1.3
Trade receivables
Trade receivables
Allowance for credit losses at December 31, 2021	38.1	$ 40.2
Current period provision (release) for expected credit losses	0.9	3.8
Recoveries	(0.5)	(5.5)
Allowance for credit losses at March 31, 2022	38.5	38.5
Contract assets
Contract assets
Allowance for credit losses at December 31, 2021	1.1	2.4
Current period provision (release) for expected credit losses	0.2	(0.6)
Recoveries	0.0	(0.7)
Allowance for credit losses at March 31, 2022	1.3	1.1
Loans receivable
Loans receivable
Allowance for credit losses at December 31, 2021	0.3	7.5
Current period provision (release) for expected credit losses	(0.1)	(0.5)
Recoveries	0.0	(1.1)
Allowance for credit losses at March 31, 2022	0.2	5.9
Security deposit and other
Security deposit and other
Allowance for credit losses at December 31, 2021	0.3	0.4
Current period provision (release) for expected credit losses	(0.3)	0.2
Recoveries	0.0	0.0
Allowance for credit losses at March 31, 2022	0.0	0.6
Held-to-maturity debt securities
Held-to-maturity debt securities
Allowance for credit losses at December 31, 2021	2.7	0.5
Current period provision (release) for expected credit losses	(0.6)	(0.5)
Recoveries	0.0	0.0
Allowance for credit losses at March 31, 2022	$ 2.1	$ 0.0