Employee Benefits - Summary of Components of Net Periodic Postretirement Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Total net periodic postretirement and postemployment benefit cost	$ 5.1	$ 4.3	$ 8.4
Salaried VEBA
Defined Benefit Plan Disclosure [Line Items]
Interest cost	2.2	2.2
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	3.4	3.6	3.8
Interest cost	1.7	1.6	1.3
Expected return on plan assets	(1.5)	(1.4)	(1.1)
Amortization of prior service cost	0.9	0.8	0.4
Amortization of net actuarial gain	(0.1)
Settlement gain recognized	0.0	(0.5)
Total net periodic postretirement and postemployment benefit cost	4.4	4.1	4.4
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1.0	1.1	1.1
Interest cost	3.5	3.3	3.4
Amortization of net actuarial gain	(1.9)	(1.1)	(1.1)
Total net periodic postretirement and postemployment benefit cost	2.6	3.3	3.4
Postretirement Health Coverage | Salaried VEBA
Defined Benefit Plan Disclosure [Line Items]
Interest cost	2.2	2.2	2.9
Expected return on plan assets	(2.3)	(2.2)	(2.2)
Amortization of prior service cost	3.0	1.7	4.9
Amortization of net actuarial gain	(0.4)	(0.1)
Total net periodic postretirement and postemployment benefit cost	$ 2.5	$ 1.6	$ 5.6