Quarterly Financial Information - Unaudited (Notes)

12 Months Ended

Dec. 31, 2015

Selected Quarterly Financial Information [Abstract]

Quarterly Financial Information (Unaudited)

Quarterly Financial Information (Unaudited)

Following is a summary of unaudited quarterly financial information:

	First Quarter		Second Quarter		Third Quarter		Fourth Quarter		Year
	(in millions, except per-share amounts)
2015
Revenues	$	428.6	$	199.3	$	142.3	$	364.7	$	1,134.9
Operating income	147.0		75.3		62.3		89.8		374.4
Net income	84.6		40.6		32.6		50.9		208.7
Asset impairment charge, before income taxes	—		—		—		12.1		12.1
Pension settlement costs, before income taxes	—		—		—		16.7		16.7
Basic earnings per common share	$	0.48	$	0.23	$	0.18	$	0.29	$	1.18
Diluted earnings per common share	0.48		0.23		0.18		0.29		1.18
2014
Revenues	$	456.9	$	201.3	$	157.9	$	373.2	$	1,189.3
Operating income	148.3		76.5		68.9		111.7		405.4
Net income	85.1		40.3		38.6		62.5		226.5
Basic earnings per common share	$	0.48	$	0.23	$	0.22	$	0.36	$	1.29
Diluted earnings per common share	0.48		0.23		0.22		0.35		1.29