Debt instrument redeem date.

No definition available.

Name:	pkg_DebtInstrumentRedeemDate
Namespace Prefix:	pkg_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument redemption amount.

+ References

No definition available.

+ Details

Name:	pkg_DebtInstrumentRedemptionAmount
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt instrument redemption amount included premiums, accrued and unpaid interest.

+ References

No definition available.

+ Details

Name:	pkg_DebtInstrumentRedemptionAmountIncludedPremiumsAccruedAndUnpaidInterest
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Long term debt maturities repayments of principal in year five and thereafter.

+ References

No definition available.

+ Details

Name:	pkg_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFiveAndThereafter
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(8))
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399

+ Details

Name:	us-gaap_AmortizationOfFinancingCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Increase for accrued, but unpaid interest on the debt instrument for the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Name:	us-gaap_DebtInstrumentIncreaseAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

+ Details

Name:	us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

Name:	us-gaap_ExtinguishmentOfDebtAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash paid for interest, including, but not limited to, capitalized interest and payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount; classified as operating and investing activities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

+ Details

Name:	us-gaap_InterestPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

+ Details

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

+ References

No definition available.

+ Details

Name:	us-gaap_LongtermDebtPercentageBearingFixedInterestAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

+ Details

Name:	us-gaap_PaymentsOfDebtIssuanceCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The excess of the (1) fair value of consideration transferred to the holders of a security in excess of (2) the carrying amount of the security reported on the registrant's balance sheet, which will be deducted from net earnings to derive net earnings available to common shareholders. This amount is generally an adjustment considered in the computation of earnings per share.

+ References

No definition available.

+ Details

Name:	us-gaap_RedemptionPremium
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_RepaymentsOfLongTermDebtAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

+ Details

Name:	us-gaap_WriteOffOfDeferredDebtIssuanceCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_TreasuryLockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_ThreePointZeroPercentageSeniorNotesDueDecemberTwoThousandAndTwentyNineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_FourPointZeroFivePercentageSeniorNotesDueDecemberTwoThousandAndFortyNineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_TwoPointFourFivePercentageSeniorNotesDueDecemberTwoThousandAndTwentyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_SeniorNotesThreePointNinePercentageSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_A4Point50SeniorNotesDueNovember2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_ThreePointSixFiveSeniorNotesDueSeptemberTwoThousandAndTwentyFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_ThreePointFourPercentageSeniorNotesDueDecemberTwoThousandAndTwentySevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_FixedRateSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_SeniorNotesSixPointFivePercentageSeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=pkg_RedemptionPremiumsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt - Additional Information (Details) - USD ($)								1 Months Ended	3 Months Ended	12 Months Ended
Debt - Additional Information (Details) - USD ($)	Dec. 23, 2019	Dec. 06, 2019	Nov. 21, 2019	Dec. 13, 2017	Sep. 05, 2014	Oct. 22, 2013	Jun. 26, 2012	Nov. 30, 2019	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 18, 2013
Annual Principal Maturities for Debt [Abstract]
2020									$ 0	$ 0
2021									0	0
2022									0	0
2023									700,000,000.0	700,000,000.0
2024 and thereafter									1,800,000,000	1,800,000,000
Interest payments										114,000,000.0	$ 97,000,000.0	$ 96,300,000
Amortization of net (loss) gain on treasury lock										(18,200,000)	(5,300,000)	(5,700,000)
Amortization of financing costs										4,500,000	$ 2,700,000	4,000,000.0
Write-off of deferred debt issuance costs								$ 1,800,000				$ 1,800,000
Treasury Lock
Annual Principal Maturities for Debt [Abstract]
Amortization of net (loss) gain on treasury lock								$ (13,100,000)	(13,100,000)
Senior Notes
Debt Instrument [Line Items]
Debt issuance costs										8,300,000
Unsecured Debt \| Revolving Credit Facility
Debt Instrument [Line Items]
Debt, face amount													$ 1,650,000,000
Line of Credit
Debt Instrument [Line Items]
Credit facility borrowing capacity													$ 350,000,000.0
Unused borrowing capacity									329,200,000	329,200,000
Line of Credit \| Letter of Credit
Debt Instrument [Line Items]
Outstanding letters of credit									$ 20,800,000	$ 20,800,000
3.00% Senior Notes, due December 2029
Debt Instrument [Line Items]
Stated interest rate									3.00%	3.00%
3.00% Senior Notes, due December 2029 \| Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 500,000,000.0
Stated interest rate			3.00%						3.00%	3.00%
Debt instrument, maturity date			Dec. 15, 2029							Dec. 15, 2029
4.05% Senior Notes, due December 2049
Debt Instrument [Line Items]
Stated interest rate									4.05%	4.05%
4.05% Senior Notes, due December 2049 \| Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 400,000,000.0
Stated interest rate			4.05%						4.05%	4.05%
Debt instrument, maturity date			Dec. 15, 2049							Dec. 15, 2049
2.45% Senior Notes, due December 2020
Debt Instrument [Line Items]
Stated interest rate									2.45%	2.45%		2.45%
Debt instrument, redemption amount included premiums, accrued and unpaid interest									$ 509,700,000	$ 509,700,000
2.45% Senior Notes, due December 2020 \| Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 500,000,000.0	$ 500,000,000.0
Stated interest rate		2.45%	2.45%	2.45%							2.45%
Debt instrument, maturity date			Dec. 15, 2020	Dec. 15, 2020							Dec. 15, 2020
Debt instrument, redemption amount		$ 509,700,000
Debt instrument, redemption premium		3,800,000
Debt instrument, accrued and unpaid interest		$ 5,800,000
3.90% Senior Notes, due June 2022
Debt Instrument [Line Items]
Stated interest rate									3.90%	3.90%
Debt instrument, redemption amount included premiums, accrued and unpaid interest									$ 418,700,000	$ 418,700,000
3.90% Senior Notes, due June 2022 \| Senior Notes
Debt Instrument [Line Items]
Debt, face amount			$ 400,000,000.0				$ 400,000,000.0
Stated interest rate	3.90%		3.90%				3.90%				3.90%
Debt instrument, maturity date			Jun. 15, 2022				Jun. 15, 2022				Jun. 15, 2022
Debt instrument, redeem date			2019-12
Debt instrument, redemption amount	$ 418,700,000
Debt instrument, redemption premium	18,400,000
Debt instrument, accrued and unpaid interest	$ 300,000
4.50% Senior Notes, due November 2023 \| Senior Notes
Debt Instrument [Line Items]
Debt, face amount						$ 700,000,000.0
Stated interest rate						4.50%			4.50%	4.50%	4.50%
Debt instrument, maturity date						Nov. 01, 2023				Nov. 01, 2023	Nov. 01, 2023
3.65% Senior Notes, due September 2024 \| Senior Notes
Debt Instrument [Line Items]
Debt, face amount					$ 400,000,000.0
Stated interest rate					3.65%				3.65%	3.65%	3.65%
Debt instrument, maturity date					Sep. 15, 2024					Sep. 15, 2024	Sep. 15, 2024
3.40% Senior Notes, due December 2027
Debt Instrument [Line Items]
Stated interest rate												3.40%
3.40% Senior Notes, due December 2027 \| Senior Notes
Debt Instrument [Line Items]
Debt, face amount				$ 500,000,000.0
Stated interest rate				3.40%					3.40%	3.40%	3.40%
Debt instrument, maturity date				Dec. 15, 2027						Dec. 15, 2027	Dec. 15, 2027
Fixed-Rate Senior Notes \| Senior Notes
Debt Instrument [Line Items]
Book value of fixed rate debt									$ 2,493,100,000	$ 2,493,100,000
Long-term debt (fixed-rate debt), fair value									$ 2,616,200,000	2,616,200,000
6.50% Senior Notes due March 2018 \| Senior Notes
Debt Instrument [Line Items]
Stated interest rate											6.50%
Debt instrument, maturity date											Mar. 15, 2018
Repayment of debt											$ 150,000,000.0
Term Loan \| Unsecured Debt
Debt Instrument [Line Items]
Repayment of debt												$ 1,000,000,000.0
Redemption Premiums
Annual Principal Maturities for Debt [Abstract]
Interest payments										$ 22,200,000