Pension Benefits and Postretirement Benefits Other Than Pensions (Tables)

3 Months Ended

Mar. 31, 2023

Pension Plans

Defined Benefit Plan Disclosure [Line Items]

Schedule of Defined Benefit Plans Disclosures

The components of Pension Expense for the Pension Plan for the three months ended March 31, 2023 and 2022 were:

	Three Months Ended
(Dollars in Millions)	Mar 31, 2023		Mar 31, 2022
Interest Cost on Projected Benefit Obligation	$	3.4	$	2.2
Expected Return on Plan Assets	(3.3)		(1.9)
Amortization of Prior Service Cost	0.2		0.2
Amortization of Net Actuarial Loss	—		0.4
Total Pension Expense	$	0.3	$	0.9

Postretirement Benefits Other than Pensions

Defined Benefit Plan Disclosure [Line Items]

Schedule of Defined Benefit Plans Disclosures

The components of OPEB Benefit for the OPEB Plans for the three months ended March 31, 2023 and 2022 were:

	Three Months Ended
(Dollars in Millions)	Mar 31, 2023		Mar 31, 2022
Service Cost	$	—	$	0.1
Interest Cost on Accumulated Postretirement Benefit Obligation	0.1		—
Amortization of Prior Service Credit	(0.3)		(0.3)
Amortization of Net Gain	(0.4)		(0.4)
Total OPEB Benefit	$	(0.6)	$	(0.6)