INCOME TAXES - Narrative (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets, Operating Loss Carryforwards, Components [Abstract]
Income tax benefit related to net operating loss carryforwards		$ 40.8
Income tax benefit related to net operating loss carryforwards recorded as a reduction to goodwill		26.9
Tax credit carryforwards		159.5
Tax credit carryforwards that can be carried forward indefinitely		41.2
Tax credit carryforwards expiring primarily by 2018 and 2037		118.3
Valuation Allowance
Decrease in valuation allowance		13.8
Valuation allowance at end of period		129.6
Income Taxes Paid, Net [Abstract]
Interest on income taxes accrued		4.1	$ 3.4
Income tax penalties accrued		1.1	1.4
Unrecognized tax benefits including tax interest accrued		74.4	52.3
Tax positions for which the ultimate deductibility is highly certain but timing is uncertain		69.2	49.1
Change in unrecognized tax benefits unrelated to Federal income taxes statute of limitations expiring within twelve months of current reporting period		24.5
Tax benefits that would impact effective tax rate		24.3
Reduction in the Transition Tax	$ 9.2
Undistributed foreign earnings with no provision		2.1
Undistributed foreign earnings indefinitely reinvested outside of domestic country		41.8
Undistributed foreign earnings		171.2
Federal Tax Authority
Deferred Tax Assets, Operating Loss Carryforwards, Components [Abstract]
Net operating loss carryforwards		990.3
Net operating loss carryforwards not subject to expiration		80.2
Net operating loss carryforwards without restrictions		617.5
Interest carryforwards		95.1
State Tax Authority
Deferred Tax Assets, Operating Loss Carryforwards, Components [Abstract]
Net operating loss carryforwards		827.2
Net operating loss carryforwards without restrictions		457.4
Tax credit carryforwards		2.4
Foreign Tax Authority
Deferred Tax Assets, Operating Loss Carryforwards, Components [Abstract]
Net operating loss carryforwards		436.2
Net operating loss carryforwards not subject to expiration		402.7
Net operating loss carryforwards subject to expiration within 20 years		33.5
Interest carryforwards		46.4
Tax credit carryforwards		48.7
Tax credit carryforwards related to research and development		108.4
Continuing Operations
Income Taxes Paid, Net [Abstract]
Unrecognized tax benefit (expense), net of related deferred taxes		0.5	0.3	$ (0.1)
Deferred taxes for interest on unrecognized tax benefits (continuing operations)		$ 0.2	$ 0.1	$ 0.1