INCOME TAXES - SUMMARY (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Current:
Federal	$ 171.5	$ 181.2
State	18.3	35.6	$ 8.7
Foreign	1.3	2.5	1.4
Total	191.1	219.3	10.1
Deferred:
Deferred tax expense	97.3	24.6	55.8
Total income taxes	$ 288.4	$ 243.9	$ 65.9
Difference of Income tax expense from amounts computed by applying the statutory federal rate to income from continuing operations before income taxes
Computed federal income tax expense (as a percent)	21.00%	21.00%	21.00%
State income tax (as a percent)	2.80%	3.10%	3.50%
Foreign-derived intangible income (FDII) (as a percent)	(2.40%)	(2.50%)
Valuation allowance (as a percent)		(0.30%)	(0.20%)
Foreign taxes (as a percent)	0.10%	0.20%	0.60%
Share-based payments (as a percent)		(0.20%)	(0.50%)
Other-net (as a percent)	(0.20%)	(0.50%)	1.00%
Effective income tax rate , Percent, Total	21.30%	20.80%	25.40%
Valuation allowances	$ 7.4	$ 5.3
Deferred tax assets:
Operating lease liabilities	102.9	111.7
Multi-employer withdrawal liabilities	13.3	13.8
Deferred compensation	10.9	10.4
U.S. State alternative minimum tax credits	8.8	4.6
Pension and post-retirement plans		11.1
Other	22.7	24.6
Total deferred tax assets	158.6	176.2
Valuation allowance	(7.4)	(5.3)
Total Deferred tax assets, net of valuation allowance	151.2	170.9
Deferred tax liabilities:
Basis differences for property and equipment	433.1	423.5
Operating lease right of use assets	100.7	109.3
Intangibles	42.0	41.3
Investment in SSAT	18.7	12.4
Capital Construction Fund	194.0	1.3
Other	9.2	6.0
Total deferred tax liabilities	797.7	593.8
Deferred tax liability, net , Total	$ 646.5	$ 422.9