DISCONTINUED OPERATIONS - Components of Income From Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations, net of taxes	$ 0.0	$ 91.7
Discontinued Operations, Disposed of by Sale \| ATC TIPL
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	0.0	321.5
Cost of operations	0.0	(169.4)
Depreciation, amortization and accretion	0.0	(40.6)
Selling, general, administrative and development expense	0.0	(12.7)
Other operating expense	0.0	(3.2)
Operating income	0.0	95.6
Interest income	0.0	17.0
Interest expense	0.0	(2.9)
Other expense, net	0.0	(0.1)
Income from discontinued operations before taxes	0.0	109.6
Income tax provision	0.0	(17.9)
Income from discontinued operations, net of taxes	$ 0.0	$ 91.7

Disposal Group, Including Discontinued Operation, Other Income (Expense), Net

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Disposal Group, Including Discontinued Operation, Other Operating Expense

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Amount before tax of income (loss) from a discontinued operation. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

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Amount of costs of goods sold attributable to disposal group, including, but not limited to, discontinued operation.

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Amount of depreciation and amortization expense attributable to disposal group, including, but not limited to, discontinued operation.

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Amount of interest expense attributable to disposal group, including, but not limited to, discontinued operation.

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Amount of operating income (loss) attributable to disposal group, including, but not limited to, discontinued operation.

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Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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