Employee Benefits - Summary of Components of Net Periodic Postretirement Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Total net periodic postretirement benefit cost	$ 1.5	$ 2.2	$ 3.3	$ 6.1
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.7	1.0	2.7	2.8
Interest cost	0.4	0.3	1.2	0.9
Expected return on plan assets	(0.3)	(0.3)	(1.0)	(0.8)
Amortization of prior service cost	0.2	0.2	0.5	0.3
Total net periodic postretirement benefit cost	1.0	1.2	3.4	3.2
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.3	0.3	0.8	0.8
Interest cost	0.8	0.8	2.5	2.5
Amortization of net actuarial gain	(0.3)	(0.3)	(0.8)	(0.9)
Total net periodic postretirement benefit cost	0.8	0.8	2.5	2.4
Postretirement Health Coverage | Salaried VEBA
Defined Benefit Plan Disclosure [Line Items]
Interest cost	0.5	0.7	1.6	2.1
Expected return on plan assets	(0.6)	(0.6)	(1.7)	(1.7)
Amortization of prior service cost	0.8	1.2	1.0	3.7
Total net periodic postretirement benefit cost	$ 0.7	$ 1.3	$ 0.9	$ 4.1