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Amount of lease cost recognized by lessee for lease contract.

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Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

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LEASES - Lease costs (Details) - USD ($) $ in Millions	12 Months Ended
LEASES - Lease costs (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Interest on lease liabilities	$ 5.9	$ 7.6	$ 38.5
Total lease cost	925.9	1,069.9
Depreciation and amortization
Lessee, Lease, Description [Line Items]
Amortization of finance lease assets	6.7	9.2
Finance lease obligations
Lessee, Lease, Description [Line Items]
Interest on lease liabilities	5.9	7.6
Theatres \| Rent
Lessee, Lease, Description [Line Items]
Operating lease cost	813.7	876.0
Variable lease cost	70.4	91.8
Theatres \| Operating expense
Lessee, Lease, Description [Line Items]
Operating lease cost	2.8	9.1
Equipment \| Operating expense
Lessee, Lease, Description [Line Items]
Operating lease cost	14.6	14.4
Variable lease cost	6.4	56.3
Office And Other \| General and administrative: other
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 5.4	$ 5.5