Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Net sales	$ 1,417.4	$ 1,454.3	$ 2,818.4	$ 2,880.0
Cost of sales	(1,097.3)	(1,136.6)	(2,199.3)	(2,285.3)
Gross profit	320.1	317.7	619.1	594.7
Selling, general, and administrative expenses	(114.8)	(115.9)	(229.1)	(233.2)
Other expense, net	(5.1)	(4.2)	(9.0)	(6.8)
Income from operations	200.2	197.6	381.0	354.7
Interest expense, net	(22.5)	(22.2)	(44.1)	(41.4)
Income before taxes	177.7	175.4	336.9	313.3
Income tax provision	(61.8)	(61.4)	(117.3)	(108.5)
Net income	$ 115.9	$ 114.0	$ 219.6	$ 204.8
Net income per common share:
Basic (in dollars per share)	$ 1.23	$ 1.16	$ 2.32	$ 2.09
Diluted (in dollars per share)	1.23	1.16	2.32	2.08
Dividends declared per common share (in dollars per share)	$ 0.55	$ 0.55	$ 1.10	$ 1.10
Statements of Comprehensive Income:
Net income	$ 115.9	$ 114.0	$ 219.6	$ 204.8
Foreign currency translation adjustment	0.0	4.2	0.0	2.8
Reclassification adjustments to cash flow hedges included in net income, net of tax of $0.6 million, $0.5 million, $1.1 million, and $1.1 million	0.8	0.9	1.7	1.7
Amortization of pension and postretirement plans actuarial loss and prior service cost, net of tax of $1.0 million, $1.4 million, $2.0 million, and $2.8 million	1.6	2.2	3.2	4.4
Changes in unfunded employee benefit obligations net of tax of $2.0 million and $2.0 million	3.1	0.0	3.1	0.0
Other comprehensive income	5.5	7.3	8.0	8.9
Comprehensive income	$ 121.4	$ 121.3	$ 227.6	$ 213.7