v3.26.1
Accumulated Other Comprehensive Income - Schedule of Accumulated Other Comprehensive Income (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance $ 826.1 $ 743.1
Other comprehensive income, net of tax 5.2 2.6
Ending balance 877.3 756.8
Defined Benefit Plans:    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 22.5 19.1
Less: income tax benefit [1] (0.1) (0.1)
Other comprehensive income, net of tax 0.2 0.1
Ending balance 22.7 19.2
Defined Benefit Plans: Actuarial Loss    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Unrealized gain on cash flow hedges   (0.1)
Reclassification of unrealized gain upon settlement of cash flow hedges [2] (0.6) (0.6)
Defined Benefit Plans: Net Prior Service Cost    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Reclassification of unrealized gain upon settlement of cash flow hedges [2] 0.9 0.9
Cash Flow Hedges:    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 4.3 1.4
Unrealized gain on cash flow hedges 15.8 8.7
Less: income tax expense (3.7) (2.0)
Net unrealized gain on cash flow hedges 12.1 6.7
Reclassification of unrealized gain upon settlement of cash flow hedges (9.3) (5.5)
Less: income tax benefit [1] 2.2 1.3
Net gain reclassified from AOCI to Net income (7.1) (4.2)
Other comprehensive income, net of tax 5.0 2.5
Ending balance [3] 9.3 3.9
Accumulated Other Comprehensive Income (Loss)    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Beginning balance 26.8 20.5
Other comprehensive income, net of tax 5.2 2.6
Ending balance $ 32.0 $ 23.1
[1] Income tax amounts reclassified out of AOCI were included as a component of Income tax provision.
[2] Amounts amortized out of AOCI related to pension and other postretirement and postemployment benefits were included within Net periodic postretirement and postemployment benefit cost (see Note 3).
[3] As of March 31, 2026, we estimate a net mark-to-market gain before tax of $13.0 million in AOCI will be reclassified into Net income upon settlement within the next 12 months.