LEASES - Lease costs (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Lessee, Lease, Description [Line Items]
Interest expense on lease liabilities	$ 1.0	$ 1.2	$ 3.2	$ 4.0
Total lease cost	243.6	230.6	734.2	646.0
Depreciation and amortization
Lessee, Lease, Description [Line Items]
Amortization of finance lease assets	0.6	1.1	2.0	3.7
Finance lease obligations
Lessee, Lease, Description [Line Items]
Interest expense on lease liabilities	0.9	1.2	3.1	4.0
57 Theatres \| Rent
Lessee, Lease, Description [Line Items]
Operating lease cost	202.0	186.4	608.9	552.6
Variable lease cost	21.2	28.5	59.9	59.9
57 Theatres \| Operating expense (income)
Lessee, Lease, Description [Line Items]
Operating lease cost	1.5	0.7	4.1	0.8
Equipment \| Operating expense (income)
Lessee, Lease, Description [Line Items]
Operating lease cost	2.7	3.4	7.4	8.0
Variable lease cost	13.4	7.9	44.8	12.9
Office And Other \| General and administrative: other
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 1.3	$ 1.4	$ 4.0	$ 4.1

Amount of interest expense on finance lease liability.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 4
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-URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918638-209977

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
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-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971

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- Definition

Amount of amortization expense attributable to right-of-use asset from finance lease.

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- Definition

Amount of lease cost recognized by lessee for lease contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980

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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

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