Retirement Benefits (Tables)

6 Months Ended

Jun. 30, 2020

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 June 30,
	2020			2019			2020			2019
	(In millions)
Interest cost on benefit obligation	$	10.6		$	13.1		$	0.2		$	0.3
Expected return on assets	(15.1		)	(16.2		)	—			—
Amortization of prior service costs (credits)	—			0.1			—			—
Amortization of net losses (gains)	14.4			10.2			(1.0		)	(1.0		)
Retirement benefits expense (income)	$	9.9		$	7.2		$	(0.8	)	$	(0.7	)

	Pension Benefits						Postretirement Medical and Life Insurance Benefits
	Six months ended June 30,
	2020			2019			2020			2019
	(In millions)
Interest cost on benefit obligation	$	21.2		$	26.3		$	0.4		$	0.6
Expected return on assets	(30.2		)	(32.4		)	—			—
Amortization of prior service costs (credits)	0.1			0.1			—			(0.1		)
Amortization of net losses (gains)	28.7			20.4			(1.9		)	(1.9		)
Retirement benefits expense (income)	$	19.8		$	14.4		$	(1.5	)	$	(1.4	)