Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Net sales	$ 1,484.0	$ 1,470.8	$ 4,302.4	$ 4,350.8
Cost of sales	(1,154.5)	(1,142.5)	(3,353.8)	(3,427.9)
Gross profit	329.5	328.3	948.6	922.9
Selling, general, and administrative expenses	(116.9)	(112.7)	(346.0)	(345.9)
Other income (expense), net	(6.2)	3.8	(15.2)	(2.9)
Income from operations	206.4	219.4	587.4	574.1
Interest expense, net	(23.4)	(21.7)	(67.5)	(63.2)
Income before taxes	183.0	197.7	519.9	510.9
Income tax provision	(63.7)	(69.9)	(181.0)	(178.3)
Net income	119.3	127.8	338.9	332.6
Less net income attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Net income attributable to Packaging Corporation of America	$ 119.3	$ 127.8	$ 338.9	$ 332.6
Net income per common share attributable to Packaging Corporation of America common shareholders:
Basic (in dollars per share)	$ 1.27	$ 1.31	$ 3.59	$ 3.39
Diluted (in dollars per share)	1.26	1.31	3.58	3.39
Dividends declared per common share (in dollars per share)	$ 0.63	$ 0.55	$ 1.73	$ 1.65
Statements of Comprehensive Income:
Net income	$ 119.3	$ 127.8	$ 338.9	$ 332.6
Foreign currency translation adjustment	0.0	0.0	0.0	2.8
Reclassification adjustments to cash flow hedges included in net income, net of tax of $0.5 million, $0.5 million, $1.6 million, and $1.6 million	0.9	0.9	2.6	2.6
Amortization of pension and postretirement plans actuarial loss and prior service cost, net of tax of $1.0 million, $1.4 million, $3.1 million, and $4.2 million	1.8	2.1	5.0	6.5
Changes in unfunded employee benefit obligations net of tax of $2.0 million	0.0	0.0	3.1	0.0
Other comprehensive income	2.7	3.0	10.7	11.9
Less net income attributable to noncontrolling interests	0.0	0.0	0.0	0.0
Comprehensive income attributable to Packaging Corporation of America	$ 122.0	$ 130.8	$ 349.6	$ 344.5