v3.19.3.a.u2
INVESTMENTS - Rollforwards (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Mar. 14, 2019
Jun. 18, 2018
Mar. 15, 2018
Jun. 30, 2017
Changes in carrying amount of investment in NCM and equity in losses of NCM              
Balance at the beginning of the period $ 232.4            
Balance at the end of the period 239.1 $ 232.4          
Common Membership Units rollforward              
Price per share (in dollars per share)   $ 6.86         $ 7.42
Total impairment loss $ 87.9 $ 13.8 $ 43.6        
Number of shares issued     616.8        
Exhibitor Services Agreement              
Common Membership Units rollforward              
Term of amortization of the exhibitor services agreement (ESA) with NCM 30 years            
NCM              
Changes in carrying amount of investment in NCM and equity in losses of NCM              
Balance at the beginning of the period   161.1 $ 323.9        
Surrender of common units for transferred theatres $ (6.3) (6.3) (36.4)        
Receipt of excess cash distributions   (15.3) (28.6)        
Other-than-temporary impairment loss - held for sale   (14.4) (206.3)        
Equity in earnings   3.2 15.3        
Receipt of common units     235.2        
Surrender of common units for make whole agreement     (23.1)        
Equity in loss from amortization of basis difference     (2.4)        
Sale of common units   (128.3)          
Balance at the end of the period     $ 161.1        
Common Membership Units rollforward              
Units exchanged for NCM, Inc. shares     (116.5)        
Surrender of common units for transferred theatres (6.3) (6.3) $ (36.4)        
Price per share (in dollars per share)       $ 7.24 $ 7.30 $ 5.64  
Gain (loss) on sale   28.9 (22.2)        
NCM | Exhibitor Services Agreement              
Changes in carrying amount of investment in NCM and equity in losses of NCM              
Balance at the beginning of the period (564.0) (530.9) (359.2)        
ASC 606 revenue recognition change in amortization method   (52.9)          
Surrender of common units for transferred theatres 5.2 5.2 35.7        
Amortization of ESA 15.7 14.6 27.8        
Receipt of common units (1.4)   (235.2)        
Balance at the end of the period (549.7) (564.0) (530.9)        
Common Membership Units rollforward              
Surrender of common units for transferred theatres $ 5.2 5.2 35.7        
Term of amortization of the exhibitor services agreement (ESA) with NCM 30 years            
NCM | Other Comprehensive (Income)              
Changes in carrying amount of investment in NCM and equity in losses of NCM              
Balance at the beginning of the period   (2.5) (4.0)        
Equity in earnings   0.1 1.5        
Sale of common units   2.4          
Balance at the end of the period     (2.5)        
NCM | Cash Received (Paid)              
Changes in carrying amount of investment in NCM and equity in losses of NCM              
Balance at the beginning of the period $ 170.7 28.6          
Receipt of excess cash distributions   15.3 28.6        
Sale of common units   156.8          
Expenses on sale of shares   (1.4)          
Balance at the end of the period   170.7 28.6        
NCM | Equity in (Earnings)/Loss              
Changes in carrying amount of investment in NCM and equity in losses of NCM              
Balance at the beginning of the period (17.3) 193.1          
Surrender of common units for transferred theatres 1.1 1.1 0.7        
Other-than-temporary impairment loss - held for sale   14.4 206.3        
Equity in earnings   (3.3) (16.8)        
Surrender of common units for make whole agreement     0.5        
Equity in loss from amortization of basis difference     2.4        
Sale of common units   (30.9)          
Expenses on sale of shares   1.4          
Balance at the end of the period   (17.3) 193.1        
Common Membership Units rollforward              
Surrender of common units for transferred theatres 1.1 1.1 0.7        
NCM | G&A: Mergers and Acquisitions Expense              
Changes in carrying amount of investment in NCM and equity in losses of NCM              
Balance at the beginning of the period   22.6          
Surrender of common units for make whole agreement     22.6        
Balance at the end of the period     22.6        
NCM | Advertising (Revenue)              
Changes in carrying amount of investment in NCM and equity in losses of NCM              
Balance at the beginning of the period (14.6) (27.8)          
Amortization of ESA (15.7) (14.6) (27.8)        
Balance at the end of the period $ (15.7) $ (14.6) $ (27.8)