OTHER COMPREHENSIVE INCOME (Tables)	12 Months Ended
	Dec. 31, 2021
OTHER COMPREHENSIVE INCOME [Abstract]
Accumulated Other Comprehensive Income, Net of Tax	in millions2021 2020 2019 AOCI Interest rate hedges$          (22.5) $         (24.0) $         (11.0) Pension and postretirement plans (130.2) (157.3) (186.7) Total$        (152.7) $       (181.3) $       (197.7)
Changes in Accumulated Other Comprehensive Income, Net of Tax	Pension and Interest Rate Postretirement in millionsHedges Benefit Plans Total AOCI Balances at December 31, 2018$          (11.2) $       (161.0) $       (172.2) Other comprehensive income (loss) before reclassifications 0.0  (26.9) (26.9) Amounts reclassified from AOCI 0.2  1.2  1.4  Net OCI changes 0.2  (25.7) (25.5) Balances at December 31, 2019$          (11.0) $       (186.7) $       (197.7) Other comprehensive income (loss) before reclassifications (14.7) 6.4  (8.3) Amounts reclassified from AOCI 1.7  23.0  24.7  Net OCI changes (13.0) 29.4  16.4  Balances at December 31, 2020$          (24.0) $       (157.3) $       (181.3) Other comprehensive income (loss) before reclassifications 0.0  13.4  13.4  Amounts reclassified from AOCI 1.5  13.7  15.2  Net OCI changes 1.5  27.1  28.6  Balances at December 31, 2021$          (22.5) $       (130.2) $       (152.7)
Amounts Reclassified from Accumulated Other Comprehensive Income to Earnings	in millions2021 2020 2019 Amortization of Interest Rate Hedge Losses Interest expense$             2.0  $            2.3  $            0.3  Benefit from income taxes (0.5) (0.6) (0.1) Total$             1.5  $            1.7  $            0.2  Amortization of Pension and Postretirement Plan Actuarial Loss and Prior Service Cost Other nonoperating expense$           18.5  $          31.2  $            1.6  Benefit from income taxes (4.8) (8.2) (0.4) Total$           13.7  $          23.0  $            1.2  Total reclassifications from AOCI to earnings$           15.2  $          24.7  $            1.4