STOCKHOLDERS' DEFICIT - Equity statements (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Increase (Decrease) in Stockholders' Equity
Balance at the beginning of the period	$ (2,031.0)	$ (1,847.9)	$ (2,590.3)	$ (2,624.5)	$ (1,847.9)	$ (2,624.5)
Net loss	(32.8)	(163.5)	8.6	(235.5)	(196.3)	(226.9)
Other comprehensive income (loss)	2.8	(35.4)	(40.0)	(7.3)
Debt for equity exchange	116.4	14.2
Share issuance	243.6		32.7	70.5
Taxes paid for restricted unit withholdings		(2.2)	(1.1)	(13.1)
Share issuance costs		(0.5)
Stock-based compensation	4.4	4.3	7.5	25.9
Balance at the end of the period	(1,696.6)	(2,031.0)	(2,582.6)	(2,590.3)	(1,696.6)	(2,582.6)
Carrying value of corporate borrowings	4,302.9				4,302.9		$ 4,504.3
Forward purchase agreement
Increase (Decrease) in Stockholders' Equity
Share issuance				193.7
Conversion of principal amount				118.6
Preferred Stock
Increase (Decrease) in Stockholders' Equity
Balance at the beginning of the period			0.1	0.1		0.1
Balance at the end of the period			0.1	0.1		0.1
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity
Balance at the beginning of the period	6,237.7	6,221.9	5,326.8	5,049.8	6,221.9	5,049.8
Debt for equity exchange	116.1	14.2
Share issuance	242.9		32.7	70.5
Taxes paid for restricted unit withholdings		(2.2)	(1.1)	(13.1)
Share issuance costs		(0.5)
Stock-based compensation	4.4	4.3	7.5	25.9
Balance at the end of the period	6,601.1	6,237.7	5,365.9	5,326.8	6,601.1	5,365.9
Additional Paid-in Capital | Forward purchase agreement
Increase (Decrease) in Stockholders' Equity
Share issuance				193.7
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity
Balance at the beginning of the period	(113.6)	(78.2)	(84.6)	(77.3)	(78.2)	(77.3)
Other comprehensive income (loss)	2.8	(35.4)	(40.0)	(7.3)
Balance at the end of the period	(110.8)	(113.6)	(124.6)	(84.6)	(110.8)	(124.6)
Accumulated Earnings (Deficit)
Increase (Decrease) in Stockholders' Equity
Balance at the beginning of the period	(8,157.7)	(7,994.2)	(7,833.1)	(7,597.6)	(7,994.2)	(7,597.6)
Net loss	(32.8)	(163.5)	8.6	(235.5)
Balance at the end of the period	(8,190.5)	(8,157.7)	(7,824.5)	(7,833.1)	(8,190.5)	(7,824.5)
Class A common stock | Common Stock
Increase (Decrease) in Stockholders' Equity
Balance at the beginning of the period	$ 2.6	$ 2.6	$ 0.5	$ 0.5	$ 2.6	$ 0.5
Balance (in shares)	263,604,984	260,574,392	51,919,238	51,683,892	260,574,392	51,683,892
Debt for equity exchange (shares)	25,004,075	2,541,250
Debt for equity exchange	$ 0.3
Share issuance	$ 0.7
Stock issued in period (in shares)	72,549,972
Stock-based compensation (in shares)	195,924	489,342		235,346
Balance at the end of the period	$ 3.6	$ 2.6	$ 0.5	$ 0.5	$ 3.6	$ 0.5
Balance (in shares)	361,354,955	263,604,984	51,919,238	51,919,238	361,354,955	51,919,238
Common Stock | Board of Director
Increase (Decrease) in Stockholders' Equity
Stock issued in period (in shares)					195,924
Stock-based compensation (in shares)				8,555
Common Stock | RSU and PSU Units
Increase (Decrease) in Stockholders' Equity
Shares Vested				226,791
Series A Convertible Participating Preferred Stock | Preferred Stock
Increase (Decrease) in Stockholders' Equity
Balance (in shares)			9,741,909	7,245,872		7,245,872
Stock issued in period (in shares)			212,156	492,880
Stock-based compensation (in shares)				26,944
Balance (in shares)			9,954,065	9,741,909		9,954,065
Series A Convertible Participating Preferred Stock | Preferred Stock | Forward purchase agreement
Increase (Decrease) in Stockholders' Equity
Stock issued in period (in shares)				1,976,213
AMC Preferred Stock Depository Shares | Preferred Stock
Increase (Decrease) in Stockholders' Equity
Balance (in shares)			97,419,080	72,458,706		72,458,706
Stock issued in period (in shares)			2,121,562	4,928,800
Stock-based compensation (in shares)				269,444
Balance (in shares)			99,540,642	97,419,080		99,540,642
AMC Preferred Stock Depository Shares | Preferred Stock | Forward purchase agreement
Increase (Decrease) in Stockholders' Equity
Stock issued in period (in shares)				19,762,130
AMC Preferred Equity Units
Increase (Decrease) in Stockholders' Equity
Net proceeds from AMC Preferred Equity Units issuance				$ 75.1
AMC Preferred Equity Units | Board of Director
Increase (Decrease) in Stockholders' Equity
Shares awarded			15,370
AMC Preferred Equity Units | RSU and PSU Units
Increase (Decrease) in Stockholders' Equity
Stock-based compensation (in shares)				254,074