PENSION AND POST-RETIREMENT BENEFITS - Summary of Amounts Recognized in Respect to Pension Plans and Other Post-retirement Benefit Plans (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Other long-term assets	$ 109.1	$ 121.1
Accrued expenses and other	(420.9)	(414.9)
Pension and other post-retirement benefit liabilities	(212.4)	(181.2)
Accumulated other comprehensive loss, gross	312.6
Income tax benefit	(51.5)
Portion allocated to Revlon Holdings	(0.6)
Accumulated other comprehensive loss, net	260.5
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Other long-term assets	1.3	3.6
Accrued expenses and other	(6.2)	(2.7)
Pension and other post-retirement benefit liabilities	(198.6)	(168.2)
Total liability	(203.5)	(167.3)
Accumulated other comprehensive loss, gross	307.5	266.1
Income tax benefit	(50.6)	(48.7)
Portion allocated to Revlon Holdings	(0.8)	(0.8)
Accumulated other comprehensive loss, net	256.1	216.6
Other Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Other long-term assets	0.0	0.0
Accrued expenses and other	(0.7)	(0.4)
Pension and other post-retirement benefit liabilities	(13.8)	(13.0)
Total liability	(14.5)	(13.4)
Accumulated other comprehensive loss, gross	5.1	4.0
Income tax benefit	(0.9)	(1.0)
Portion allocated to Revlon Holdings	0.2	0.2
Accumulated other comprehensive loss, net	$ 4.4	$ 3.2