INCOME TAXES - DEFERRED ASSETS AND LIABILITIES (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Jan. 01, 2021
Deferred tax assets:
Net federal operating loss carryforwards	$ 100.1	$ 166.0
Net state operating loss carryforwards	2.5	2.5
Insurance liabilities	312.8	298.5
Indirect costs allocable to self-constructed real estate assets	244.5	214.8
Accumulated other comprehensive loss	552.6	552.4
Other	2.9	7.3
Gross deferred tax assets	1,215.4	1,241.5
Deferred tax liabilities:
Investments	(30.8)	(37.2)
Present value of future profits and deferred acquisition costs	(158.6)	(148.9)
Gross deferred tax liabilities	(189.4)	(186.1)
Net deferred tax assets	1,026.0	1,055.4
Current income taxes prepaid	13.8	8.0
Income tax assets, net	$ 1,039.8	$ 1,063.4	$ 806.4

Deferred Income Tax Assets, Net, Including Net of Current Income Tax Payable

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Deferred Tax Assets, Indirect Costs Allocable to Self-Constructed Real Estate Assets

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Prepaid (Accrued) Income Taxes, Current

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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-Name Accounting Standards Codification
-Section 50
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Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, without jurisdictional netting.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible domestic operating loss carryforwards. Excludes state and local operating loss carryforwards.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible state and local operating loss carryforwards.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from unrealized losses in other comprehensive income.

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The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from estimated policyholder reserves, which will be deductible from future taxable income when actual costs are incurred, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the tax deduction to be taken.

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

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The amount as of the balance sheet date of the estimated future tax effects attributable to policy acquisition costs being expensed for tax purposes but capitalized in conformity with generally accepted accounting principles, which will reverse in future periods when amortization of such capitalized costs cannot be deducted for tax purposes.

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Amount of deferred tax liability attributable to taxable temporary differences from investments (excludes investments in subsidiaries and equity method investments).

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