LEASES - Lease costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Lessee, Lease, Description [Line Items]
Interest expense on lease liabilities	$ 1.0	$ 1.4	$ 2.2	$ 2.8
Total lease cost	247.5	215.9	490.6	415.4
Rent
Lessee, Lease, Description [Line Items]
Operating lease cost	204.4	190.7	406.9	366.2
Operating expense (income)
Lessee, Lease, Description [Line Items]
Operating lease cost	1.4		2.6	0.1
Operating lease cost		(0.7)
Depreciation and amortization
Lessee, Lease, Description [Line Items]
Amortization of finance lease assets	0.7	1.3	1.4	2.6
Finance lease obligations
Lessee, Lease, Description [Line Items]
Interest expense on lease liabilities	1.0	1.4	2.2	2.8
57 Theatres | Rent
Lessee, Lease, Description [Line Items]
Variable lease cost	18.0	14.8	38.7	31.4
Equipment | Operating expense (income)
Lessee, Lease, Description [Line Items]
Operating lease cost	1.9	2.3	4.7	4.6
Variable lease cost	18.8	4.8	31.4	5.0
Office And Other | General and administrative: other
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 1.3	$ 1.3	$ 2.7	$ 2.7