Retirement Benefits (Tables)

9 Months Ended

Sep. 30, 2022

Retirement Benefits [Abstract]

Schedule of Components of Retirement Benefit Expense (Benefit)

The following table presents the components of retirement benefits expense (income): 

	Pension Benefits				Postretirement Medical and Life Insurance Benefits
	Three months ended September 30,
	2022		2021		2022		2021
	(In millions)
Interest cost on benefit obligation	$	8.9	$	8.4	$	0.1	$	0.1
Expected return on assets	(15.7)		(15.3)		—		—
Amortization of net losses (gains)	7.6		16.0		(0.7)		(0.7)
Retirement benefits expense (income)	$	0.8	$	9.1	$	(0.6)	$	(0.6)

	Pension Benefits				Postretirement Medical and Life Insurance Benefits
	Nine months ended September 30,
	2022		2021		2022		2021
	(In millions)
Interest cost on benefit obligation	$	26.7	$	25.1	$	0.3	$	0.4
Expected return on assets	(47.2)		(46.0)		—		—
Amortization of prior service costs	0.1		0.1		—		—
Amortization of net losses (gains)	22.9		47.9		(2.1)		(2.1)
Retirement benefits expense (income)	$	2.5	$	27.1	$	(1.8)	$	(1.7)