Stockholders' Equity - Reclassifications Out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2016	[2]	Sep. 30, 2016	[3]	Jun. 30, 2016	[4]	Mar. 31, 2016	[5]	Dec. 31, 2015	[6]	Sep. 30, 2015	[7]	Jun. 30, 2015	[8]	Mar. 31, 2015	[9]	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest expense, net																	$ (91.8)	$ (85.5)	$ (88.4)	[1]
Income before taxes																	688.5	664.5	614.3
Provision for income taxes																	(238.9)	(227.7)	(221.7)
Net income attributable to Packaging Corporation of America	$ 110.6		$ 119.4		$ 115.9		$ 103.7		$ 104.3		$ 127.8		$ 114.0		$ 90.8		449.6	436.8	$ 392.6
Unfunded Employee Benefit Obligations | Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Amortization of prior service cost																	(5.5)	(5.6)
Amortization of actuarial gain / (losses)																	(5.4)	(8.8)
Income before taxes																	(10.9)	(14.4)
Provision for income taxes																	4.2	5.6
Net income attributable to Packaging Corporation of America																	(6.7)	(8.8)
Foreign Exchange Contract | Foreign Currency Translation Adjustments | Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest expense, net																	0.0	(4.2)
Provision for income taxes																	0.0	0.0
Net income attributable to Packaging Corporation of America																	0.0	(4.2)
Treasury Lock | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges | Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Interest expense, net																	(5.7)	(5.7)
Provision for income taxes																	2.2	2.2
Net income attributable to Packaging Corporation of America																	$ (3.5)	$ (3.5)

[1] Includes $1.5 million of expense related to the write-off of deferred financing costs in connection with the debt refinancing discussed in Note 9, Debt.

[2] Includes $4.5 million of closure costs related to a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No.1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of acquisition-related costs for TimBar Corporation and Columbus Container, Inc. acquisitions ($0.8 million after-tax or $0.01 per diluted share).

[3] Includes $2.0 million of closure costs related to a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of acquisition-related costs for TimBar Corporation and Columbus Container, Inc. acquisitions ($1.9 million after-tax or $0.02 per diluted share).

[4] Includes $1.7 million of closure costs related to a corrugated products facility and a paper products facility ($1.0 million after-tax or $0.01 per diluted share), $0.3 million of acquisition-related costs for TimBar Corporation ($0.2 million after-tax or $0.0 per diluted share), and $0.9 million related to our withdrawal from a multiemployer pension plan for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share).

[5] Includes $2.8 million of closure costs related to a corrugated products facility and a paper products facility. ($1.9 million after-tax or $0.02 per diluted share).

[6] Includes $3.5 million of income from DeRidder restructuring ($2.2 million after-tax or $0.02 per diluted share) and $3.8 million of integration-related and other costs ($2.6 million after-tax or $0.03 per diluted share).

[7] Includes $3.8 million of income from DeRidder restructuring ($2.3 million after-tax or $0.02 per diluted share) and $2.4 million of integration-related and other costs ($1.7 million after-tax or $0.02 per diluted share). Also includes $6.7 million gain from the sale of our paper mill site at St. Helens, Oregon ($4.4 million after tax or $0.05 per diluted share).

[8] Includes $1.0 million of income from DeRidder restructuring ($0.7 million after-tax or $0.01 per diluted share) and $3.7 million of integration-related and other costs ($2.3 million after-tax or $0.03 per diluted share).

[9] Includes $10.3 million of DeRidder restructuring charges ($6.6 million after-tax or $0.07 per diluted share) and $3.5 million of integration-related and other costs ($2.2 million after-tax or $0.02 per diluted share). Also includes a $3.6 million tax credit from the State of Louisiana related to our capital investment and the jobs retained at the DeRidder, Louisiana mill.