Pension Benefits and Postretirement Benefits Other Than Pensions (Tables)

9 Months Ended

Sep. 30, 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 nine and three months ended September 30, 2023 and 2022 were:

	Nine Months Ended				Three Months Ended
(Dollars in Millions)	Sep 30, 2023		Sep 30, 2022		Sep 30, 2023		Sep 30, 2022
Interest Cost on Projected Benefit Obligation	$	8.4	$	6.5	$	1.5	$	2.2
Expected Return on Plan Assets	(7.9)		(5.6)		(1.4)		(1.9)
Amortization of Prior Service Cost	0.4		0.5		0.1		0.2
Amortization of Net Actuarial Loss	—		1.3		—		0.4
Pension Settlement Expense	70.2		—		70.2		—
Total Pension Expense	$	71.1	$	2.7	$	70.4	$	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 nine and three months ended September 30, 2023 and 2022 were:

	Nine Months Ended				Three Months Ended
(Dollars in Millions)	Sep 30, 2023		Sep 30, 2022		Sep 30, 2023		Sep 30, 2022
Service Cost	$	0.1	$	0.1	$	—	$	—
Interest Cost on Accumulated Postretirement Benefit Obligation	0.3		0.1		0.1		—
Amortization of Prior Service Credit	(1.0)		(1.0)		(0.3)		(0.3)
Amortization of Net Gain	(1.3)		(1.3)		(0.4)		(0.5)
Total OPEB Benefit	$	(1.9)	$	(2.1)	$	(0.6)	$	(0.8)