Retirement Benefits - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer	$ 3.9
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected contribution for next fiscal year	3.9
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected contribution for next fiscal year	$ 1.1