PENSION AND POSTRETIREMENT LIABILITIES: (Tables)

3 Months Ended

Mar. 31, 2013

PENSION AND POSTRETIREMENT LIABILITIES:

Net periodic benefit cost of defined benefit pension plans

	Three months ended
	March 31,
($ in millions)	2013			2012
Service cost	$	3.3		$	2.4
Interest cost	6.9			7.9
Expected return on assets	(3.6		)	(3.9		)
Amortization of actuarial losses	4.2			1.8
Amortization of prior service cost	0.2			0.2
Total pension cost	$	11.0		$	8.4