Three Months Ended March 31,

2024

2023

2024

2023

(dollars in millions)

Pension Benefits

Postretirement and Other Benefits

Service cost

$

—

$

—

$

0.1

$

0.1

Other components of pension and postretirement benefit plans expense:

Interest cost on projected benefit obligation

5.1

5.5

1.2

1.3

Expected return on plan assets

(5.7

)

(5.2

)

—

—

Amortization of:

Prior service benefit

—

—

(0.2

)

(0.2

)

Actuarial gain

—

(0.1

)

(0.9

)

(0.9

)

Pension / postretirement (benefit) cost

$

(0.6

)

$

0.2

$

0.2

$

0.3