OTHER CURRENT ASSETS & OTHER CURRENT LIABILITIES - Other Current Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Other Current Assets and Other Current Liabilities [Abstract]
Warranty accruals and project contingencies	$ 175.9	$ 168.8
Legal provisions	131.9	127.6
Value - added tax and other taxes payable	103.5	109.6
Social security liability	66.7	67.9
Compensation accrual	42.1	54.3
Provisions	35.3	53.0
Current portion of accrued pension and other post-retirement benefits	6.8	6.9
TIOS non-controlling interest	48.7	0.0
Other accrued liabilities	194.8	230.2
Total other current liabilities	$ 805.7	$ 818.3