Retirement Benefits - Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive (Loss) (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	$ 0.1	$ (9.4)
Accumulated other comprehensive (income) loss, gross	0.1	(9.4)
Deferred income tax provision	0.0	2.3
Accumulated other comprehensive (income) loss, net	0.1	(7.1)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	(0.3)	(8.7)
Accumulated other comprehensive (income) loss, gross	(0.3)	(8.7)
Deferred income tax provision	0.1	2.1
Accumulated other comprehensive (income) loss, net	(0.2)	(6.6)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	0.4	(0.7)
Accumulated other comprehensive (income) loss, gross	0.4	(0.7)
Deferred income tax provision	(0.1)	0.2
Accumulated other comprehensive (income) loss, net	$ 0.3	$ (0.5)