FAIR VALUE MEASUREMENTS - Fair value on a nonrecurring basis (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Other Fair Value Measurement Disclosures
Current maturities of corporate borrowings, carrying value	$ 20.0	$ 20.0
Corporate borrowings, noncurrent, carrying value	5,439.4	$ 5,695.8
Total Carrying Value
Other Fair Value Measurement Disclosures
Current maturities of corporate borrowings, carrying value	20.0
Corporate borrowings, noncurrent, carrying value	5,439.4
Significant other observable inputs (Level 2)
Other Fair Value Measurement Disclosures
Current maturities of corporate borrowings, fair value	17.4
Corporate borrowings, noncurrent, fair value	3,838.9
Significant unobservable inputs (Level 3)
Other Fair Value Measurement Disclosures
Corporate borrowings, noncurrent, fair value	$ 719.5

The fair value of the long-term debt current maturities which are not separately disclosed in the statement of financial position.

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- References

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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