Employee benefit plans (Tables)

9 Months Ended

Sep. 30, 2012

Other postretirement benefits [Member]

Defined benefit plans

Other postretirement benefits - The components of our net periodic other postretirement benefit cost are presented in the table below.

	Three months  ended September 30,						Nine months  ended September 30,
	2011			2012			2011			2012
	(In millions)
Service cost	$	.1		$	.1		$	.2		$	.2
Interest cost		.2			.1			.7			.6
Amortization of prior service credit		(.6	)		(.5	)		(1.7	)		(1.4	)
Recognized actuarial losses		—			.1			—			.1
Total	$	(.3	)	$	(.2	)	$	(.8	)	$	(.5	)

Defined benefit plans [Member]

Defined benefit plans

Defined benefit plans - The components of our net periodic defined benefit pension cost are presented in the table below.

	Three months  ended September 30,						Nine months ended September 30,
	2011			2012			2011			2012
	(In millions)
Service cost	$	2.8		$	2.5		$	8.3		$	7.7
Interest cost		6.9			6.2			20.5			19.1
Expected return on plan assets		(5.8	)		(5.5	)		(17.2	)		(16.5	)
Amortization of unrecognized:
Prior service cost		.3			.4			1.1			1.2
Net transition obligations		.2			.1			.4			.3
Recognized actuarial losses		1.9			2.3			5.6			6.9
Total	$	6.3		$	6.0		$	18.7		$	18.7