Non-operating Income (Expense) (Tables)

12 Months Ended

Dec. 31, 2014

Nonoperating Income (Expense) [Abstract]

Schedule of Other Nonoperating Income (Expense) [Table Text Block]

	Year ended December 31,
Dollar amounts in millions	2014			2013			2012
Interest expense	$	(29.9	)	$	(36.2	)	$	(48.0	)
Amortization of debt charges	(1.2		)	(1.4		)	(1.5		)
Capitalized interest	1.3			1.6			0.2
Interest expense, net of capitalized interest	(29.8		)	(36.0		)	(49.3		)
Investment income	5.5			9.4			13.0
SERP market adjustments	—			0.9			1.8
Investment income	5.5			10.3			14.8
Foreign currency losses	(3.1		)	(5.3		)	(2.7		)
Gain on settlement of litigation related to ARS	—			—			20.0
Gain on acquisition	—			35.9			—
Gain on the sale of joint venture	—			1.2			—
Early debt extinguishment	—			(2.3		)	(52.2		)
Other non-operating income (expense)	(3.1		)	29.5			(34.9		)
Total non-operating income (expense)	$	(27.4	)	$	3.8		$	(69.4	)