Retirement benefits (Tables)

3 Months Ended

Mar. 31, 2017

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Benefit Costs

The components of net periodic pension cost for our pension plans were as follows:

	U.S. Plans					Non-U.S. Plans				Total
(In millions)	2017			2016		2017		2016		2017		2016
Three months ended March 31,
Service cost	$	—		—		2.9		2.8		2.9		2.8
Interest cost on projected benefit obligation	8.8			9.2		4.8		3.4		13.6		12.6
Return on assets – expected	(13.3		)	(13.7	)	(2.4	)	(2.3	)	(15.7	)	(16.0	)
Amortization of losses	6.3			6.1		1.3		1.2		7.6		7.3
Amortization of prior service cost	—			—		0.2		—		0.2		—
Settlement loss	—			—		0.3		0.8		0.3		0.8
Net periodic pension cost	$	1.8		1.6		7.1		5.9		8.9		7.5

Schedule of Costs of Retirement Plans

The components of net periodic postretirement cost related to retirement benefits other than pensions were as follows:

	UMWA Plans					Black Lung and Other Plans		Total
(In millions)	2017			2016		2017	2016	2017		2016
Three months ended March 31,
Interest cost on accumulated postretirement benefit obligations	$	4.4		4.6		0.7	0.6	5.1		5.2
Return on assets – expected	(4.2		)	(4.4	)	—	—	(4.2	)	(4.4	)
Amortization of losses	4.4			4.3		0.9	0.5	5.3		4.8
Amortization of prior service (credit) cost	(1.1		)	(1.1	)	0.5	0.5	(0.6	)	(0.6	)
Net periodic postretirement cost	$	3.5		3.4		2.1	1.6	5.6		5.0