FAIR VALUE - Items Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Cash equivalents:
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Assets, Current, Sundry	Assets, Current, Sundry
Liabilities:
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Liabilities, Noncurrent, Other current liabilities	Liabilities, Noncurrent, Other current liabilities
Fair Value, Measurements, Recurring | Total
Cash equivalents:
Derivative assets (Note 12)	$ 3.5	$ 2.9
Total assets	201.2	174.7
Liabilities:
Derivative liabilities (Note 12)	4.2	5.9
Total liabilities	50.5	49.9
Fair Value, Measurements, Recurring | Total | Diversified investments associated with the ESU program
Cash equivalents:
Diversified investments associated with the ESU program	45.7	42.8
Fair Value, Measurements, Recurring | Total | Liabilities associated with the ESUP
Liabilities:
Liabilities associated with the ESU program	46.3	44.0
Fair Value, Measurements, Recurring | Total | Bank time deposits with original maturities of three months or less
Cash equivalents:
Bank time deposits with original maturities of three months or less	152.0	129.0
Fair Value, Measurements, Recurring | Level 1
Cash equivalents:
Derivative assets (Note 12)	0.0	0.0
Total assets	45.7	42.8
Liabilities:
Derivative liabilities (Note 12)	0.0	0.0
Total liabilities	46.3	44.0
Fair Value, Measurements, Recurring | Level 1 | Diversified investments associated with the ESU program
Cash equivalents:
Diversified investments associated with the ESU program	45.7	42.8
Fair Value, Measurements, Recurring | Level 1 | Liabilities associated with the ESUP
Liabilities:
Liabilities associated with the ESU program	46.3	44.0
Fair Value, Measurements, Recurring | Level 1 | Bank time deposits with original maturities of three months or less
Cash equivalents:
Bank time deposits with original maturities of three months or less	0.0	0.0
Fair Value, Measurements, Recurring | Level 2
Cash equivalents:
Derivative assets (Note 12)	3.5	2.9
Total assets	155.5	131.9
Liabilities:
Derivative liabilities (Note 12)	4.2	5.9
Total liabilities	4.2	5.9
Fair Value, Measurements, Recurring | Level 2 | Diversified investments associated with the ESU program
Cash equivalents:
Diversified investments associated with the ESU program	0.0	0.0
Fair Value, Measurements, Recurring | Level 2 | Liabilities associated with the ESUP
Liabilities:
Liabilities associated with the ESU program	0.0	0.0
Fair Value, Measurements, Recurring | Level 2 | Bank time deposits with original maturities of three months or less
Cash equivalents:
Bank time deposits with original maturities of three months or less	152.0	129.0
Fair Value, Measurements, Recurring | Level 3
Cash equivalents:
Derivative assets (Note 12)	0.0	0.0
Total assets	0.0	0.0
Liabilities:
Derivative liabilities (Note 12)	0.0	0.0
Total liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Level 3 | Diversified investments associated with the ESU program
Cash equivalents:
Diversified investments associated with the ESU program	0.0	0.0
Fair Value, Measurements, Recurring | Level 3 | Liabilities associated with the ESUP
Liabilities:
Liabilities associated with the ESU program	0.0	0.0
Fair Value, Measurements, Recurring | Level 3 | Bank time deposits with original maturities of three months or less
Cash equivalents:
Bank time deposits with original maturities of three months or less	$ 0.0	$ 0.0