Common Stock (Tables)

12 Months Ended

Dec. 31, 2015

Common Stock.

Summary of shares repurchased

	Years Ended December 31,
	2015				2014
	Number of shares repurchased		Cost of shares repurchased		Number of shares repurchased		Cost of shares repurchased
	(amounts in millions, except share amount)
Stock repurchase programs:
April 30, 2013		497,010	$	27.3		669,681	$	39.6
July 27, 2015		315,530		17.3		—		—
Total		812,540	$	44.6		669,681	$	39.6