Plum Creek Timber (PCL) 10-Q 6 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Entity Registrant Name	PLUM CREEK TIMBER CO INC
Entity Central Index Key	849213
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		175,626,328
PLUM CREEK TIMBERLANDS L P [Member]
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Entity Registrant Name	Plum Creek Timberlands LP
Entity Central Index Key	1296350
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest Expense, net:
Net Income	$42	$30
PER SHARE AMOUNTS:
Net Income per Share-Basic	$0.24	$0.17
Net Income per Share-Diluted	$0.24	$0.17
Weighted-Average Number of Shares Outstanding
-Basic	175.9	177
-Diluted	176.2	177.3
PLUM CREEK TIMBER CO INC [Member]
REVENUES:
Timber	192	192
Real Estate	109	23
Manufacturing	94	90
Energy and Natural Resources	8	9
Other	3	3
Total Revenues	406	317
COSTS AND EXPENSES:
Timber	139	138
Real Estate	89	10
Manufacturing	83	79
Energy and Natural Resources	2	2
Other	2	3
Total Cost of Goods Sold	315	232
Selling, General and Administrative	33	29
Total Costs and Expenses	348	261
Other Operating Income (Expense), net	3	1
Operating Income	61	57
Earnings from Unconsolidated Entities	22	14
Interest Expense, net:
Interest Expense (Debt Obligations to Unrelated Parties)	27	27
Interest Expense (Note Payable to Timberland Venture)	14	14
Total Interest Expense, net	41	41
Income before Income Taxes	42	30
Provision (Benefit) for Income Taxes	0	0
Net Income	42	30
PER SHARE AMOUNTS:
Net Income per Share-Basic	$0.24	$0.17
Net Income per Share-Diluted	$0.24	$0.17
Dividends Declared - per Common Share Outstanding	$0.44	$0.44
Weighted-Average Number of Shares Outstanding
-Basic	175.9	177
-Diluted	176.2	177.3
PLUM CREEK TIMBERLANDS L P [Member]
REVENUES:
Timber	192	192
Real Estate	109	23
Manufacturing	94	90
Energy and Natural Resources	8	9
Other	3	3
Total Revenues	406	317
COSTS AND EXPENSES:
Timber	139	138
Real Estate	89	10
Manufacturing	83	79
Energy and Natural Resources	2	2
Other	2	3
Total Cost of Goods Sold	315	232
Selling, General and Administrative	33	29
Total Costs and Expenses	348	261
Other Operating Income (Expense), net	3	1
Operating Income	61	57
Earnings from Unconsolidated Entities	22	14
Interest Expense, net:
Total Interest Expense, net	27	27
Income before Income Taxes	56	44
Provision (Benefit) for Income Taxes	0	0
Net Income before Allocation to Series T-1 Preferred Interest and Partners	56	44
Net Income Allocable to Series T-1 Preferred Interest	-14	-14
Net Income	42	30
Timberland Venture [Member] | PLUM CREEK TIMBER CO INC [Member]
COSTS AND EXPENSES:
Earnings from Unconsolidated Entities	23	15
Timberland Venture [Member] | PLUM CREEK TIMBERLANDS L P [Member]
COSTS AND EXPENSES:
Earnings from Unconsolidated Entities	23	15
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member]
COSTS AND EXPENSES:
Earnings from Unconsolidated Entities	-1	-1
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member]
COSTS AND EXPENSES:
Earnings from Unconsolidated Entities	($1)	($1)

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Net Income	$42	$30
PLUM CREEK TIMBER CO INC [Member]
Net Income	42	30
Defined Benefit Pension Plans [Abstract]
Amortization of Actuarial Loss Reclassified to Pension Expense	1	0
Unrealized Gains (Losses) on Grantor Trust Assets [Abstract]
Unrealized Holding Gains (Losses) Arising During Period	-1	1
Reclassification for Amounts Recognized in Net Income	-1	0
Other Comprehensive Income (Loss), before Tax	-1	1
Income Tax Expense (Benefit) Related to Items of Other Comprehensive Income	0	0
Other Comprehensive Income (Loss) After Tax	-1	1
Comprehensive Income	41	31
PLUM CREEK TIMBERLANDS L P [Member]
Net Income	42	30
Net Income before Allocation to Series T-1 Preferred Interest and Partners	56	44
Defined Benefit Pension Plans [Abstract]
Amortization of Actuarial Loss Reclassified to Pension Expense	1	0
Unrealized Gains (Losses) on Grantor Trust Assets [Abstract]
Unrealized Holding Gains (Losses) Arising During Period	-1	1
Reclassification for Amounts Recognized in Net Income	-1	0
Other Comprehensive Income (Loss), before Tax	-1	1
Income Tax Expense (Benefit) Related to Items of Other Comprehensive Income	0	0
Other Comprehensive Income (Loss) After Tax	-1	1
Comprehensive Income	$55	$45

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
PLUM CREEK TIMBER CO INC [Member]
Current Assets:
Cash and Cash Equivalents	$94	$92
Accounts Receivable	47	38
Inventories	59	61
Deferred Tax Asset	6	6
Assets Held for Sale	54	98
Other Current Assets	15	15
Total Current Assets	275	310
Timber and Timberlands, net	3,958	4,009
Minerals and Mineral Rights, net	288	289
Property, Plant and Equipment, net	118	120
Equity Investment in Timberland Venture	210	217
Equity Investment in Real Estate Development Ventures	125	126
Deferred Tax Asset	23	23
Investment in Grantor Trusts ($48 and $48 at Fair Value in 2015 and 2014)	48	48
Other Assets	41	45
Total Assets	5,086	5,187
Current Liabilities:
Current Portion of Long-Term Debt	439	439
Line of Credit	56	95
Accounts Payable	32	27
Interest Payable	34	22
Wages Payable	12	31
Taxes Payable	10	10
Deferred Revenue	16	23
Other Current Liabilities	10	10
Total Current Liabilities	609	657
Long-Term Debt	1,976	1,976
Note Payable to Timberland Venture	783	783
Other Liabilities	100	100
Total Liabilities	3,468	3,516
Commitments and Contingencies
Stockholders' Equity
Preferred Stock, $0.01 Par Value, Authorized Shares - 75.0, Outstanding - None	0	0
Common Stock, $0.01 Par Value, Authorized Shares - 300.6, Outstanding (net of Treasury Stock) - 175.6 at March 31, 2015 and 175.9 at December 31, 2014	2	2
Additional Paid-In Capital	2,959	2,955
Retained Earnings (Accumulated Deficit)	-306	-271
Treasury Stock, at Cost, Common Shares - 28.7 at March 31, 2015 and 28.3 at December 31, 2014	-1,013	-992
Accumulated Other Comprehensive Income (Loss)	-24	-23
Total Stockholders' Equity	1,618	1,671
Total Liabilities and Stockholders' Equity	5,086	5,187
PLUM CREEK TIMBERLANDS L P [Member]
Current Assets:
Cash and Cash Equivalents	94	92
Accounts Receivable	47	38
Inventories	59	61
Deferred Tax Asset	6	6
Assets Held for Sale	54	98
Other Current Assets	15	15
Total Current Assets	275	310
Timber and Timberlands, net	3,958	4,009
Minerals and Mineral Rights, net	288	289
Property, Plant and Equipment, net	118	120
Equity Investment in Timberland Venture	210	217
Equity Investment in Real Estate Development Ventures	125	126
Deferred Tax Asset	23	23
Investment in Grantor Trusts ($48 and $48 at Fair Value in 2015 and 2014)	49	49
Other Assets	41	45
Total Assets	5,087	5,188
Current Liabilities:
Current Portion of Long-Term Debt	439	439
Line of Credit	56	95
Accounts Payable	32	27
Interest Payable	27	15
Wages Payable	12	31
Taxes Payable	10	10
Deferred Revenue	16	23
Other Current Liabilities	10	10
Total Current Liabilities	602	650
Long-Term Debt	1,976	1,976
Other Liabilities	101	101
Total Liabilities	2,679	2,727
Commitments and Contingencies
Stockholders' Equity
Accumulated Other Comprehensive Income (Loss)	-24	-23
PARTNERSHIP CAPITAL
Series T-1 Preferred Interest	790	790
Partners' Capital (Common Partnership Interests)	1,618	1,671
Total Partnership Capital	2,408	2,461
Total Liabilities and Partnership Capital	$5,087	$5,188

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets Parenthetical (Parentheticals) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, except Per Share data, unless otherwise specified
PLUM CREEK TIMBER CO INC [Member]
Preferred Stock, Par or Stated Value Per Share	$0.01	$0.01
Preferred Stock, Shares Authorized	75	75
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$0.01	$0.01
Common Stock, Shares Authorized	300.6	300.6
Common Stock, Shares, Outstanding	175.6	175.9
Treasury Stock, Shares	28.7	28.3
PLUM CREEK TIMBERLANDS L P [Member]
Other Marketable Securities Noncurrent Fair Value	$48	$48

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	$42	$30
PLUM CREEK TIMBER CO INC [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	42	30
Adjustments to Reconcile Net Income to Net Cash Provided By Operating Activities:
Depreciation, Depletion and Amortization	33	32
Basis of Real Estate Sold	83	6
Earnings from Unconsolidated Entities	-22	-14
Distributions from Timberland Venture	30	28
Working Capital Changes	-16	-25
Other	1	0
Net Cash Provided By (Used In) Operating Activities	151	57
CASH FLOWS FROM INVESTING ACTIVITIES
Capital Expenditures (Excluding Timberland Acquisitions)	-14	-16
Timberlands Acquired	0	0
Contributions to Real Estate Development Ventures	-2	-4
Distributions from Real Estate Development Ventures	2	0
Sales (Purchases) of Marketable Securities, net	1	0
Net Cash Provided By (Used In) Investing Activities	-13	-20
CASH FLOWS FROM FINANCING ACTIVITIES
Dividends	-77	-78
Borrowings on Line of Credit	58	283
Repayments on Line of Credit	-97	-570
Proceeds from Stock Option Exercises	1	1
Acquisition of Treasury Stock	-21	-2
Net Cash Provided By (Used In) Financing Activities	-136	-366
Increase (Decrease) In Cash and Cash Equivalents	2	-329
Cash and Cash Equivalents:
Beginning of Period	92	433
End of Period	94	104
PLUM CREEK TIMBERLANDS L P [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	42	30
Net Income before Allocation to Series T-1 Preferred Interest and Partners	56	44
Adjustments to Reconcile Net Income to Net Cash Provided By Operating Activities:
Depreciation, Depletion and Amortization	33	32
Basis of Real Estate Sold	83	6
Earnings from Unconsolidated Entities	-22	-14
Distributions from Timberland Venture	30	28
Working Capital Changes	-16	-25
Other	1	0
Net Cash Provided By (Used In) Operating Activities	165	71
CASH FLOWS FROM INVESTING ACTIVITIES
Capital Expenditures (Excluding Timberland Acquisitions)	-14	-16
Timberlands Acquired	0	0
Contributions to Real Estate Development Ventures	-2	-4
Distributions from Real Estate Development Ventures	2	0
Sales (Purchases) of Marketable Securities, net	1	0
Net Cash Provided By (Used In) Investing Activities	-13	-20
CASH FLOWS FROM FINANCING ACTIVITIES
Cash Distributions to Common Partners	-97	-79
Cash Distributions for Series T-1 Preferred Interest	-14	-14
Borrowings on Line of Credit	58	283
Repayments on Line of Credit	-97	-570
Net Cash Provided By (Used In) Financing Activities	-150	-380
Increase (Decrease) In Cash and Cash Equivalents	2	-329
Cash and Cash Equivalents:
Beginning of Period	92	433
End of Period	$94	$104

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Basis of Presentation	Basis of Presentation
	General. When we refer to “Plum Creek,” “the company,” “we,” “us,” or “our,” we mean Plum Creek Timber Company, Inc., a Delaware Corporation and a real estate investment trust, or “REIT,” and all of its wholly-owned consolidated subsidiaries.
	The consolidated financial statements include all of the accounts of Plum Creek and its subsidiaries. At March 31, 2015, the company owned and managed approximately 6.4 million acres of timberlands in the Northwest, Southern, and Northeast United States. Included in the 6.4 million acres are approximately 675,000 acres of higher value timberlands, which are expected to be sold and/or developed over the next fifteen years for recreational, conservation or residential purposes. Included within the 675,000 acres of higher value timberlands are approximately 500,000 acres we expect to sell for recreational uses, approximately 100,000 acres we expect to sell for conservation and approximately 75,000 acres that are identified as having development potential. In addition, the company has approximately 225,000 acres of non-strategic timberlands, which are expected to be sold in smaller acreage transactions over the near and medium term. In the meantime, all of our timberlands continue to be managed productively in our business of growing and selling timber. At March 31, 2015, the company owned seven wood product conversion facilities in the Northwest United States. In March 2015, due to the loss of a significant customer, the company permanently closed its remanufacturing facility in Meridian, Idaho.
	Plum Creek has elected to be taxed as a REIT under sections 856-860 of the United States Internal Revenue Code and, as such, generally does not pay corporate-level income tax. However, the company conducts certain non-REIT activities through various taxable REIT subsidiaries, which are subject to corporate-level income tax. These activities include our manufacturing operations, the harvesting and selling of logs, the development and/or sale of some of our higher value timberlands, timber and wood fiber procurement services, coal leases, and the company's investment in real estate development ventures. Plum Creek’s overall effective tax rate is lower than the federal statutory corporate rate due to Plum Creek’s status as a REIT.
	Intercompany transactions and accounts have been eliminated in consolidation. All transactions are denominated in United States dollars.
	The consolidated financial statements included in this Form 10-Q are unaudited and do not contain all of the information required by U.S. generally accepted accounting principles to be included in a full set of financial statements. The consolidated balance sheet at December 31, 2014 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements. The audited financial statements in the company’s 2014 Annual Report on Form 10-K include a summary of significant accounting policies of the company and should be read in conjunction with this Form 10-Q. In the opinion of management, all material adjustments necessary to present fairly the results of operations for such periods have been included in this Form 10-Q. All such adjustments are of a normal and recurring nature. The results of operations for interim periods are not necessarily indicative of the results of operations for the entire year.
	Reclassifications. Certain prior year amounts have been reclassified to conform to the 2015 presentation. The reclassifications had no impact on operating income or net income.
PLUM CREEK TIMBERLANDS L P [Member]
Basis of Presentation	Basis of Presentation
	General. Plum Creek Timberlands, L.P. is a Delaware Limited Partnership and a wholly-owned subsidiary of Plum Creek Timber Company, Inc. (“Parent”), a Delaware Corporation and a real estate investment trust, or “REIT.” References herein to “the Operating Partnership,” “we,” “us,” or “our” relate to Plum Creek Timberlands, L.P. and all of its wholly-owned consolidated subsidiaries; references to “Plum Creek” or “Parent” relate to Plum Creek Timber Company, Inc. and all of its wholly-owned consolidated subsidiaries.
	At March 31, 2015, the Operating Partnership owned and managed approximately 6.4 million acres of timberlands in the Northwest, Southern and Northeast United States. Included in the 6.4 million acres are approximately 675,000 acres of higher value timberlands, which are expected to be sold and/or developed over the next fifteen years for recreational, conservation or residential purposes. Included within the 675,000 acres of higher value timberlands are approximately 500,000 acres we expect to sell for recreational uses, approximately 100,000 acres we expect to sell for conservation and approximately 75,000 acres that are identified as having development potential. In addition, the Operating Partnership has approximately 225,000 acres of non-strategic timberlands, which are expected to be sold in smaller acreage transactions over the near and medium term. In the meantime, all of our timberlands continue to be managed productively in our business of growing and selling timber. At March 31, 2015, the Operating Partnership owned seven wood product conversion facilities in the Northwest United States. In March 2015, due to the loss of a significant customer, the Operating Partnership permanently closed its remanufacturing facility in Meridian, Idaho.
	The consolidated financial statements of the Operating Partnership include the accounts of Plum Creek Timberlands, L.P. and its subsidiaries. The Operating Partnership is 100% owned by Plum Creek. Plum Creek has no assets or liabilities other than its direct and indirect ownership interests in Plum Creek Timberlands, L.P. and its interest in Plum Creek Ventures I, LLC (“PC Ventures”), a 100% owned subsidiary of Plum Creek. The Parent has no operations other than its investment in these subsidiaries and transactions in its own equity, such as the issuance and/or repurchase of common stock and the receipt of proceeds from stock option exercises. Intercompany transactions and accounts between Plum Creek Timberlands, L.P. and its subsidiaries have been eliminated in consolidation. All transactions are denominated in United States dollars.
	Plum Creek Timber Company, Inc. has elected to be taxed as a REIT under sections 856-860 of the United States Internal Revenue Code and, as such, generally does not pay corporate-level income tax. However, the Operating Partnership conducts certain non-REIT activities through various wholly-owned taxable REIT subsidiaries, which are subject to corporate-level income tax. These activities include our manufacturing operations, the harvesting and selling of logs, the development and/or sale of some of the Operating Partnership's higher value timberlands, timber and wood fiber procurement services, coal leases, and the Operating Partnership's investment in real estate development ventures. The Operating Partnership’s tax provision includes the tax expense and/or benefit associated with Plum Creek’s wholly-owned taxable REIT subsidiaries, as well as any tax expense and/or benefit incurred by the REIT. The effective tax rate for the Operating Partnership is lower than the federal corporate statutory rate primarily due to Plum Creek’s status as a REIT.
	The consolidated financial statements included in this Form 10-Q are unaudited and do not contain all of the information required by U.S. generally accepted accounting principles to be included in a full set of financial statements. These interim consolidated financial statements in this Form 10-Q should be read in conjunction with the audited consolidated financial statements of Plum Creek Timberlands, L.P. for the three years ended December 31, 2014, which were included on Form 10-K of Plum Creek Timber Company, Inc. and filed with the SEC on February 26, 2015, and which include a summary of significant accounting policies of the Operating Partnership. In the opinion of management, all material adjustments necessary to present fairly the results of operations for such periods have been included in this Form 10-Q. All such adjustments are of a normal and recurring nature. The results of operations for interim periods are not necessarily indicative of the results of operations for the entire year.
	Reclassifications. Certain prior year amounts have been reclassified to conform to the 2015 presentation. The reclassifications had no impact on operating income or net income.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share
	The following table sets forth the reconciliation of basic and diluted earnings per share for the quarterly periods ended March 31 (in millions, except per share amounts):
		Quarter Ended March 31,
		2015		2014
	Net Income Available to Common Stockholders	$	42	$	30
	Denominator for Basic Earnings per Share	175.9		177
	Effect of Dilutive Securities – Stock Options	0.3		0.2
	Effect of Dilutive Securities – Restricted Stock Units and Value Management Plan	—		0.1
	Denominator for Diluted Earnings per Share – Adjusted for Dilutive Securities	176.2		177.3
	Per Share Amounts:
	Net Income Per Share – Basic	$	0.24	$	0.17
	Net Income Per Share – Diluted	$	0.24	$	0.17
	Under the company's Stock Incentive Plan, the company grants restricted stock units, which prior to vesting, are entitled to non-forfeitable cash payments equal to dividends paid on the company's common shares. These awards are considered participating securities for purposes of computing basic and diluted earnings per share.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Inventories	Inventories
	Inventories, accounted for using the lower of average cost or market, consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Raw Materials (primarily logs)	$	9	$	12
	Work-In-Process	3		3
	Finished Goods	32		31
		44		46
	Supplies	15		15
	Total	$	59	$	61
PLUM CREEK TIMBERLANDS L P [Member]
Inventories	Inventories
	Inventories, accounted for using the lower of average cost or market, consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Raw Materials (primarily logs)	$	9	$	12
	Work-In-Process	3		3
	Finished Goods	32		31
		44		46
	Supplies	15		15
	Total	$	59	$	61

Timber_and_Timberlands

Timber and Timberlands	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Timber and Timberlands	Timber and Timberlands
	Timber and Timberlands consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Timber and Logging Roads, net	$	2,494	$	2,518
	Timber Deeds, net	79		83
	Timberlands	1,385		1,408
	Timber and Timberlands, net	$	3,958	$	4,009
PLUM CREEK TIMBERLANDS L P [Member]
Timber and Timberlands	Timber and Timberlands
	Timber and Timberlands consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Timber and Logging Roads, net	$	2,494	$	2,518
	Timber Deeds, net	79		83
	Timberlands	1,385		1,408
	Timber and Timberlands, net	$	3,958	$	4,009

Property_Plant_and_Equipment

Property, Plant and Equipment	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Property, Plant and Equipment	Property, Plant and Equipment
	Property, Plant and Equipment consisted of the following (in millions):
		March 31, 2015			December 31, 2014
	Land, Buildings and Improvements	$	99		$	97
	Machinery and Equipment	331			331
		430			428
	Accumulated Depreciation	(312		)	(308		)
	Property, Plant and Equipment, net	$	118		$	120
PLUM CREEK TIMBERLANDS L P [Member]
Property, Plant and Equipment	Property, Plant and Equipment
	Property, Plant and Equipment consisted of the following (in millions):
		March 31, 2015			December 31, 2014
	Land, Buildings and Improvements	$	99		$	97
	Machinery and Equipment	331			331
		430			428
	Accumulated Depreciation	(312		)	(308		)
	Property, Plant and Equipment, net	$	118		$	120

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Income Tax Disclosure [Text Block]	Income Taxes
	Plum Creek has elected to be taxed as a REIT under sections 856-860 of the United States Internal Revenue Code. A REIT generally does not pay corporate-level income tax if it distributes 100% of its taxable income to shareholders and satisfies other organizational and operational requirements as set forth in the Internal Revenue Code. If a company fails to qualify as a REIT in any taxable year, it will be subject to federal income taxes at regular corporate rates (including any applicable alternative minimum tax) and may not be able to qualify as a REIT for four subsequent taxable years.
	Plum Creek operates as a REIT through various wholly-owned subsidiaries and a joint venture partnership. The activities of the operating partnerships and joint venture partnership consist primarily of sales of standing timber under pay-as-cut sales contracts.
	Plum Creek conducts certain activities through various wholly-owned taxable REIT subsidiaries, which are subject to corporate-level income tax. These activities include the company's manufacturing operations, the harvesting and sale of logs, the development and/or sale of some of the company's higher value timberlands, timber and wood fiber procurement services, coal leases, and the company's investment in real estate development ventures. Plum Creek's taxable REIT subsidiaries file a consolidated federal income tax return.
	Prior to 2011, Plum Creek was generally subject to corporate-level tax (built-in gains tax) when the company made a taxable disposition of certain properties acquired in a 2001 merger. The built-in gains tax applied to gains recognized from such asset sales to the extent that the fair value of the property exceeded its tax basis at the merger date. Built-in gains tax was generally not payable on dispositions of property to the extent the proceeds from such dispositions were reinvested in qualifying like-kind replacement property.
	The company's 2008 federal income tax return is currently being audited by the Internal Revenue Service (“IRS”). The IRS has proposed an adjustment to the company's U.S. federal income tax treatment of the Timberland Venture formation transaction, which occurred on October 1, 2008, on the basis that the transfer of the timberlands to Southern Diversified Timber, LLC was a taxable transaction to the company at the time of the transfer rather than a nontaxable capital contribution to the Timberland Venture. The company has filed a protest with IRS Appeals.
	If the IRS's position is upheld on administrative or judicial appeal, it could result in a maximum built-in gains tax liability of approximately $100 million. In addition, the company could be required to accelerate the distribution to its stockholders of up to $600 million of gain from the transaction. The company expects that as much as 80% of any such distribution could be made with the company's common stock, and stockholders would be subject to tax on the distribution at the applicable capital gains tax rate. The company would also be required to pay interest, which could be substantial, and, if applicable, penalties.
	We believe the transfer of the timberlands was a nontaxable contribution to the Timberland Venture and not a taxable transaction. We have not accrued income taxes for financial reporting purposes with respect to this matter and do not believe it is reasonably possible any material accrual will be made within the next twelve months. We are confident in our position and believe that the proposed re-characterization of the Timberland Venture formation transaction by the IRS will ultimately be unsuccessful. We intend to vigorously contest this re-characterization.
PLUM CREEK TIMBERLANDS L P [Member]
Income Tax Disclosure [Text Block]	Income Taxes
	Plum Creek Timberlands, L.P. is a wholly-owned limited partnership and therefore, not subject to income tax. Plum Creek Timberlands, L.P.’s taxable income is allocated 100% (directly and indirectly) to its parent, Plum Creek Timber Company, Inc., which has elected to be taxed as a REIT under sections 856-860 of the United States Internal Revenue Code. A REIT generally does not pay corporate-level income tax if it distributes 100% of its taxable income to shareholders and satisfies other organizational and operational requirements as set forth in the Internal Revenue Code. If a company fails to qualify as a REIT in any taxable year, it will be subject to federal income taxes at regular corporate rates (including any applicable alternative minimum tax) and may not be able to qualify as a REIT for four subsequent taxable years.
	The Operating Partnership conducts certain non-REIT activities through various wholly-owned taxable REIT subsidiaries, which are subject to corporate-level income tax. These activities include our manufacturing operations, the harvesting and sale of logs, the development and/or sale of some of the Operating Partnership's higher value timberlands, timber and wood fiber procurement services, coal leases, and the Operating Partnership's investment in real estate development ventures. The Operating Partnership's tax provision includes the tax expense and/or benefit associated with Plum Creek's wholly-owned taxable REIT subsidiaries, as well as any tax expense and/or benefit incurred by the REIT.
	Prior to 2011, Plum Creek was generally subject to corporate-level tax (built-in gains tax) when the Operating Partnership made a taxable disposition of certain properties acquired in a 2001 merger. The built-in gains tax applied to gains recognized from such asset sales to the extent that the fair value of the property exceeded its tax basis at the merger date. Built-in gains tax was generally not payable on dispositions of property to the extent the proceeds from such dispositions were reinvested in qualifying like-kind replacement property.
	Plum Creek's 2008 federal income tax return is currently being audited by the Internal Revenue Service (“IRS”). The IRS has proposed an adjustment to Plum Creek's U.S. federal income tax treatment of the Timberland Venture formation transaction, which occurred on October 1, 2008, on the basis that the transfer of the timberlands to Southern Diversified Timber, LLC was a taxable transaction to Plum Creek at the time of the transfer rather than a nontaxable capital contribution to the Timberland Venture. Plum Creek has filed a protest with IRS Appeals.
	If the IRS's position is upheld on administrative or judicial appeal, it could result in a maximum built-in gains tax liability of approximately $100 million. In addition, Plum Creek could be required to accelerate the distribution to its stockholders of up to $600 million of gain from the transaction. Plum Creek expects that as much as 80% of any such distribution could be made with Plum Creek's common stock, and stockholders would be subject to tax on the distribution at the applicable capital gains tax rate. Plum Creek would also be required to pay interest, which could be substantial, and, if applicable, penalties.
	We believe the transfer of the timberlands was a nontaxable contribution to the Timberland Venture and not a taxable transaction. We have not accrued income taxes for financial reporting purposes with respect to this matter and do not believe it is reasonably possible any material accrual will be made within the next twelve months. We are confident in our position and believe that the proposed re-characterization of the Timberland Venture formation transaction by the IRS will ultimately be unsuccessful. We intend to vigorously contest this re-characterization.

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Borrowings	Borrowings
	Debt consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Variable Rate Debt
	Term Credit Agreement (A)	$	225	$	225
	Revolving Line of Credit (B)	56		95
	Fixed Rate Debt
	Senior Notes	1,330		1,330
	Installment Note Payable	860		860
	Note Payable to Timberland Venture	783		783
	Total Debt	3,254		3,293
	Less:
	Current Portion of Long-Term Debt	439		439
	Line of Credit	56		95
	Long-Term Portion	$	2,759	$	2,759
	(A)	The company has a $225 million term credit agreement that matures on April 3, 2019. The interest rate on the $225 million term credit agreement was 1.68% and 1.67% as of March 31, 2015 and December 31, 2014, respectively. After giving effect to expected patronage distributions, the effective net interest rate on the term loan was approximately 1% as of both March 31, 2015 and December 31, 2014.
	(B)	The weighted-average interest rate for the borrowings on the line of credit was 1.36% and 1.34% as of March 31, 2015 and December 31, 2014, respectively. As of March 31, 2015, we had $56 million of borrowings and $2 million of standby letters of credit outstanding; $642 million remained available for borrowing under our $700 million line of credit. As of April 1, 2015, all of the borrowings under our line of credit were repaid.
PLUM CREEK TIMBERLANDS L P [Member]
Borrowings	Borrowings
	Debt consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Variable Rate Debt
	Term Credit Agreement (A)	$	225	$	225
	Revolving Line of Credit (B)	56		95
	Fixed Rate Debt
	Senior Notes	1,330		1,330
	Installment Note Payable	860		860
	Total Debt	2,471		2,510
	Less:
	Current Portion of Long-Term Debt	439		439
	Line of Credit	56		95
	Long-Term Portion	$	1,976	$	1,976
	(A)	The Operating Partnership has a $225 million term credit agreement that matures on April 3, 2019. The interest rate on the $225 million term credit agreement was 1.68% and 1.67% as of March 31, 2015 and December 31, 2014, respectively. After giving effect to expected patronage distributions, the effective net interest rate on the term loan was approximately 1% as of both March 31, 2015 and December 31, 2014.
	(B)	The weighted-average interest rate for the borrowings on the line of credit was 1.36% and 1.34% as of March 31, 2015 and December 31, 2014, respectively. As of March 31, 2015, we had $56 million of borrowings and $2 million of standby letters of credit outstanding; $642 million remained available for borrowing under our $700 million line of credit. As of April 1, 2015, all of the borrowings under our line of credit were repaid.

Stockholders_Equity

Stockholders' Equity (PLUM CREEK TIMBER CO INC [Member])	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Stockholders' Equity	Stockholders’ Equity
	The changes in the company’s stockholders’ equity accounts were as follows during 2015 (in millions):
		Common Stock										Retained							Accumulated
												Earnings (Accumulated Deficit)							Other
																			Comprehensive
		Shares			Dollars				Paid-in							Treasury			Income (Loss)			Total
									Capital							Stock						Equity
	January 1, 2015	175.9			$	2			$	2,955		$	(271	)		$	(992	)	$	(23	)	$	1,671
	Net Income											42										42
	Other Comprehensive Income (Loss)																		(1		)	(1		)
	Dividends											(77		)								(77		)
	Stock Option Exercises	—			—				1													1
	Shares Issued under Stock Incentive Plans	0.2			—				—													—
	Share-based Compensation								3													3
	Common Stock Repurchased	(0.5	)		—											(21		)				(21		)
	March 31, 2015	175.6			$	2			$	2,959		$	(306	)		$	(1,013	)	$	(24	)	$	1,618
	The changes in the company’s accumulated other comprehensive income (loss) by component, net of tax, were as follows during 2015 (in millions):
		Net Unrealized Holding Gain (Loss) (A)				Defined Benefit Plan Actuarial Net Loss (B)				Gain on Cash Flow Hedge			Total
	January 1, 2015	$	14			$	(42	)		$	5		$	(23	)
	Other Comprehensive Income (Loss) before Reclassifications	(1		)		—				—			(1		)
	Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(1		)		1				—			—
	31-Mar-15	$	12			$	(41	)		$	5		$	(24	)
	(A)    Unrealized holding gains were reclassified to Other Operating Income (Expense), net in the Consolidated
	Statements of Income when the related available for sale securities are sold.
	(B)    Amortization of actuarial gains and losses on the company's defined benefit pension plans is included in the
	computation of pension cost. See Note 10 of the Notes to Consolidated Financial Statements.

Partners_Capital

Partners' Capital (PLUM CREEK TIMBERLANDS L P [Member])	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBERLANDS L P [Member]
Partners' Capital	Partners’ Capital
	The changes in the Operating Partnership’s capital accounts were as follows during 2015 (in millions):
		Preferred			Common			Accumulated			Total
		Partnership			Partners’			Other			Partnership
		Interest			Capital			Comprehensive			Capital
								Income (Loss)
	January 1, 2015	$	790		$	1,694		$	(23	)	$	2,461
	Net Income before Allocation to Series T-1 Preferred Interest and Partners				56						56
	Other Comprehensive Income (Loss)							(1		)	(1		)
	Net Income Allocation to Series T-1 Preferred Interest	14			(14		)				—
	Distributions to Partners (Common Partnership Interests)				(97		)				(97		)
	Distributions for Series T-1 Preferred Interest	(14		)							(14		)
	Capital Contributions from Parent				3						3
	March 31, 2015	$	790		$	1,642		$	(24	)	$	2,408
	The changes in the Operating Partnership's accumulated other comprehensive income (loss) by component, net of tax, were as follows during 2015 (in millions):
		Net Unrealized Holding Gain (Loss) (A)			Defined Benefit Plan Actuarial Net Loss (B)			Gain on Cash Flow Hedge			Total
	January 1, 2015	$	14		$	(42	)	$	5		$	(23	)
	Other Comprehensive Income (Loss) before Reclassifications	(1		)	—			—			(1		)
	Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(1		)	1			—			—
	31-Mar-15	$	12		$	(41	)	$	5		$	(24	)
	(A)    Unrealized holding gains were reclassified to Other Operating Income (Expense), net in the Consolidated
	Statements of Income when the related available for sale securities are sold.
	(B)    Amortization of actuarial gains and losses on the Operating Partnership's defined benefit pension plans is included in
	the computation of pension cost. See Note 9 of the Notes to Consolidated Financial Statements.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Fair Value Measurements	Fair Value Measurements
	Assets and Liabilities Measured at Fair Value on a Recurring Basis. The company’s fair value measurements of its cash equivalents, available-for-sale securities, and trading securities, measured on a recurring basis, are categorized as Level 1 measurements under the fair value hierarchy in the Accounting Standards Codification. A Level 1 valuation is based on quoted prices in active markets at the measurement date for identical unrestricted assets or liabilities. Summarized below are the Level 1 assets reported in the company’s financial statements at fair value, measured on a recurring basis (in millions):
		Balance at			Fair Value Measurements
		31-Mar-15			at Reporting Date Using
					Quoted Prices in Active
					Markets of Identical Assets
					(Level 1 Measurements)
	Cash Equivalents (A)	$	91		$	91
	Available-for-Sale Securities (B)	43			43
	Trading Securities (B)	5			5
	Total	$	139		$	139
		Balance at			Fair Value Measurements
		31-Dec-14			at Reporting Date Using
					Quoted Prices in Active
					Markets of Identical Assets
					(Level 1 Measurements)
	Cash Equivalents (A)	$	90		$	90
	Available-for-Sale Securities (B)	43			43
	Trading Securities (B)	5			5
	Total	$	138		$	138
	(A)	Consists of several money market funds and is included in the $94 million and $92 million of Cash and Cash Equivalents in the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014, respectively.
	(B)	Consists of several mutual funds and is included in Investment in Grantor Trusts in the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014. At March 31, 2015, investments in these mutual funds were approximately 45% in domestic (U.S.) equities, 25% in international equities and 30% in debt securities.
	Available-for-Sale Securities. Certain investments in the grantor trusts relate to the company's non-qualified pension plans and are classified as available-for-sale securities. The company has invested in various money market, debt and equity mutual funds and plans to use these investments to fund its non-qualified pension obligations. Unrealized holding gains and losses are included as a component of accumulated other comprehensive income. The company records changes in unrealized holding gains and losses in Other Comprehensive Income, unless an other than temporary impairment has occurred, which is then charged to expense. Changes in the fair value of available-for-sale securities were not material to the company's financial position or results of operations for the quarters ended March 31, 2015 and March 31, 2014. As of both March 31, 2015 and December 31, 2014, the amortized cost of the available-for-sale securities was approximately $31 million. See Note 8 of the Notes to Consolidated Financial Statements.
	Trading Securities. Certain investments in the grantor trusts relate to the company's deferred compensation plans and are classified as trading securities. Deferred compensation amounts are invested in various money market, debt and equity mutual funds. The company plans to use these investments to fund deferred compensation obligations. Realized gains and losses and changes in unrealized gains and losses (and a corresponding amount of compensation expense) are recognized in the company's Consolidated Statements of Income. Deferred compensation obligations are included in Other Liabilities and were $5 million at both March 31, 2015 and December 31, 2014. Changes in the fair value of trading securities were not material to the company's financial position or results of operations for the quarters ended March 31, 2015 and March 31, 2014.
	Other Instruments. Summarized below are the carrying amount and fair value of the company's debt (estimated using the discounted cash flow method) along with the categorization under the fair value hierarchy in the Accounting Standards Codification (in millions):
						Fair Value at March 31, 2015
			Carrying Amount at March 31, 2015			Quoted Prices		Significant		Significant		Total
						In Active		Observable		Unobservable
						Markets for		Inputs		Inputs
						Identical Assets		(Level 2)		(Level 3)
						(Level 1)
	Public Debt (A)		$	1,330		$	—	$	1,402	$	—	$	1,402
	Term Credit Agreement (B)		225			—		225		—		225
	Line of Credit (C)		56			—		56		—		56
	Installment Note Payable (D)		860			—		924		—		924
	Note Payable to Timberland Venture (E)		783			—		—		895		895
	Total Debt		$	3,254		$	—	$	2,607	$	895	$	3,502
						Fair Value at December 31, 2014
			Carrying Amount at			Quoted Prices		Significant		Significant		Total
			31-Dec-14			In Active		Observable		Unobservable
						Markets for		Inputs		Inputs
						Identical Assets		(Level 2)		(Level 3)
						(Level 1)
	Public Debt (A)		$	1,330		$	—	$	1,398	$	—	$	1,398
	Term Credit Agreement (B)		225			—		225		—		225
	Line of Credit (C)		95			—		95		—		95
	Installment Note Payable (D)		860			—		906		—		906
	Note Payable to Timberland Venture (E)		783			—		—		892		892
	Total Debt		$	3,293		$	—	$	2,624	$	892	$	3,516
	(A)	Fair value of the company's Public Debt (publicly issued Senior Notes) is estimated using multiple market quotes for the company's public bonds.
	(B)	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable debt.
	(C)	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable credit lines.
	(D)	Fair value is estimated by adjusting the spread over the applicable Treasury rate to a current market quote for comparable debt.
	(E)	Fair value is estimated by using market quotes for the company's Public Debt adjusted by an estimated risk premium for holding company debt and the different maturity.
	Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis. There were no fair value measurements of assets or liabilities measured on a nonrecurring basis during the three-month periods ended March 31, 2015 and 2014.
PLUM CREEK TIMBERLANDS L P [Member]
Fair Value Measurements	Fair Value Measurements
	Assets and Liabilities Measured at Fair Value on a Recurring Basis. The Operating Partnership’s fair value measurements of its cash equivalents, available-for-sale securities, and trading securities, measured on a recurring basis, are categorized as Level 1 measurements under the fair value hierarchy in the Accounting Standards Codification. A Level 1 valuation is based on quoted prices in active markets at the measurement date for identical unrestricted assets or liabilities. Summarized below are the Level 1 assets reported in the Operating Partnership’s financial statements at fair value, measured on a recurring basis (in millions):
		Balance at			Fair Value Measurements
		31-Mar-15			at Reporting Date Using
					Quoted Prices in Active
					Markets of Identical Assets
					(Level 1 Measurements)
	Cash Equivalents (A)	$	91		$	91
	Available-for-Sale Securities (B)	43			43
	Trading Securities (B)	5			5
	Total	$	139		$	139
		Balance at			Fair Value Measurements
		31-Dec-14			at Reporting Date Using
					Quoted Prices in Active
					Markets of Identical Assets
					(Level 1 Measurements)
	Cash Equivalents (A)	$	90		$	90
	Available-for-Sale Securities (B)	43			43
	Trading Securities (B)	5			5
	Total	$	138		$	138
	(A)	Consists of several money market funds and is included in the $94 million and $92 million of Cash and Cash Equivalents in the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014, respectively.
	(B)	Consists of several mutual funds and is included in Investment in Grantor Trusts in the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014. At March 31, 2015, investments in these mutual funds were approximately 45% in domestic (U.S.) equities, 25% in international equities and 30% in debt securities.
	Available-for-Sale Securities. Certain investments in the grantor trusts relate to the Operating Partnership's non-qualified pension plans and are classified as available-for-sale securities. The Operating Partnership has invested in various money market, debt and equity mutual funds and plans to use these investments to fund its non-qualified pension obligations. Unrealized holding gains and losses are included as a component of accumulated other comprehensive income. The Operating Partnership records changes in unrealized holding gains and losses in Other Comprehensive Income, unless an other than temporary impairment has occurred, which is then charged to expense. Changes in the fair value of available-for-sale securities were not material to the Operating Partnership's financial position or results of operations for the quarters ended March 31, 2015 and March 31, 2014. As of both March 31, 2015 and December 31, 2014, the amortized cost of the available-for-sale securities was approximately $31 million. See Note 7 of the Notes to Consolidated Financial Statements.
	Trading Securities. Certain investments in the grantor trusts relate to the Operating Partnership's deferred compensation plans and are classified as trading securities. Deferred compensation amounts are invested in various money market, debt and equity mutual funds. The Operating Partnership plans to use these investments to fund deferred compensation obligations. Realized gains and losses and changes in unrealized gains and losses (and a corresponding amount of compensation expense) are recognized in the Operating Partnership's Consolidated Statements of Income. Deferred compensation obligations are included in Other Liabilities and were $5 million at both March 31, 2015 and December 31, 2014. Changes in the fair value of trading securities were not material to the Operating Partnership's financial position or results of operations for the quarters ended March 31, 2015 and March 31, 2014.
	Other Instruments. Summarized below are the carrying amount and fair value of the Operating Partnership's debt (estimated using the discounted cash flow method) along with the categorization under the fair value hierarchy in the Accounting Standards Codification (in millions):
						Fair Value at March 31, 2015
			Carrying Amount at March 31, 2015			Quoted Prices		Significant		Significant		Total
						In Active		Observable		Unobservable
						Markets for		Inputs		Inputs
						Identical Assets		(Level 2)		(Level 3)
						(Level 1)
	Public Debt (A)		$	1,330		$	—	$	1,402	$	—	$	1,402
	Term Credit Agreement (B)		225			—		225		—		225
	Line of Credit (C)		56			—		56		—		56
	Installment Note Payable (D)		860			—		924		—		924
	Total Debt		$	2,471		$	—	$	2,607	$	—	$	2,607
						Fair Value at December 31, 2014
			Carrying Amount at			Quoted Prices		Significant		Significant		Total
			31-Dec-14			In Active		Observable		Unobservable
						Markets for		Inputs		Inputs
						Identical Assets		(Level 2)		(Level 3)
						(Level 1)
	Public Debt (A)		$	1,330		$	—	$	1,398	$	—	$	1,398
	Term Credit Agreement (B)		225			—		225		—		225
	Line of Credit (C)		95			—		95		—		95
	Installment Note Payable (D)		860			—		906		—		906
	Total Debt		$	2,510		$	—	$	2,624	$	—	$	2,624
	(A)	Fair value of the Operating Partnership's Public Debt (publicly issued Senior Notes) is estimated using multiple market quotes for the Operating Partnership's public bonds.
	(B)	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable debt.
	(C)	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable credit lines.
	(D)	Fair value is estimated by adjusting the spread over the applicable Treasury rate to a current market quote for comparable debt.
	Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis. There were no fair value measurements of assets or liabilities measured on a nonrecurring basis during the three-month periods ended March 31, 2015 and 2014.

Employee_Pension_Plans

Employee Pension Plans	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Employee Pension Plans	Employee Pension Plans
	The components of pension cost were as follows for the quarterly periods ended March 31 (in millions):
		Quarter Ended March 31,
		2015			2014
	Service Cost	$	2		$	2
	Interest Cost	2			2
	Expected Return on Plan Assets	(3		)	(2		)
	Recognized Actuarial Loss	1			—
	Total Pension Cost	$	2		$	2
PLUM CREEK TIMBERLANDS L P [Member]
Employee Pension Plans	Employee Pension Plans
	The components of pension cost were as follows for the quarterly periods ended March 31 (in millions):
		Quarter Ended March 31,
		2015			2014
	Service Cost	$	2		$	2
	Interest Cost	2			2
	Expected Return on Plan Assets	(3		)	(2		)
	Recognized Actuarial Loss	1			—
	Total Pension Cost	$	2		$	2

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Commitments and Contingencies	Commitments and Contingencies
	Contingencies. The company is subject to regulations regarding forest, harvest and manufacturing practices and is, from time to time, involved in various legal proceedings, including, but not limited to, environmental and regulatory matters, incidental to its business. Reserves have been established for any probable losses. Except as discussed in Note 6, management does not believe that these matters, individually or in the aggregate, are material. However, it is possible that one or more of these matters could become material in the future, and an unfavorable outcome in one or more of these matters could have a material negative financial impact on the company. See Note 6 of the Notes to Consolidated Financial Statements for a discussion of a tax proceeding involving the company and its consolidated subsidiaries.
PLUM CREEK TIMBERLANDS L P [Member]
Commitments and Contingencies	Commitments and Contingencies
	Contingencies. The Operating Partnership is subject to regulations regarding forest, harvest and manufacturing practices and is, from time to time, involved in various legal proceedings, including, but not limited to, environmental and regulatory matters, incidental to its business. Reserves have been established for any probable losses. Except as discussed in Note 5, management does not believe that these matters, individually or in the aggregate, are material. However, it is possible that one or more of these matters could become material in the future, and an unfavorable outcome in one or more of these matters could have a material negative financial impact on the Operating Partnership. See Note 5 of the Notes to Consolidated Financial Statements for a discussion of a tax proceeding involving Plum Creek.

Variable_Interest_Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Consolidation, Variable Interest Entity, Policy [Policy Text Block]	Variable Interest Entities
	Real Estate Development Ventures. MWV-Charleston Land Partners, LLC (“MWV-CLP”) is a variable interest entity. The primary activities of MWV-CLP are the active development of residential and commercial real estate on approximately 22,000 acres ("Class A Properties") and the identification, entitlement, marketing, and selling of approximately 71,000 acres of high-value rural and development-quality lands ("Class B Properties"). MWV-CLP is managed by an affiliate of MeadWestvaco Corporation ("MWV"). MWV-CLP is financed by regular capital calls from the manager of MWV-CLP in proportion to a member’s ownership interest. If a member does not make a capital contribution, the member’s ownership interest is diluted. The company made an initial capital contribution of $152 million in 2013. Also, during the years 2014 to 2020, the company agreed to make additional capital contributions of at least $48 million in connection with its interest in the Class B Properties, of which $37 million remained outstanding as of March 31, 2015. The company does not intend to provide any other sources of financing for MWV-CLP. We account for our interest in MWV-CLP under the equity method of accounting.
	The company is not the primary beneficiary of MWV-CLP. The company considers the activities that most significantly impact the economic performance of MWV-CLP to be the day-to-day operating decisions along with the oversight responsibilities for the real estate development projects and properties. MWV has the power to direct the activities of MWV-CLP that most significantly impact its economic performance through its ability to manage the day-to-day operations of MWV-CLP. MWV also has the ability to control all management decisions associated with the 22,000 acres of the Class A Properties through its majority representation on the board of directors for the Class A Properties and its joint control of the Class B Properties due to its equal representation on the board of directors for the Class B Properties.
	The carrying amount of our investment in MWV-CLP is $125 million as of March 31, 2015 and $126 million as of December 31, 2014, and is reported in the Consolidated Balance Sheets as Equity Investment in Real Estate Development Ventures. Our maximum exposure to loss is $125 million, our carrying amount of our investment, plus any future capital contributions we elect to contribute to MWV-CLP. At a minimum, the company has agreed to make capital contributions in connection with its interest in Class B Properties of $37 million over the next six years. The company has a 50% ownership interest in the Class B Properties, and therefore, is entitled to 50% of the earnings or losses associated with these properties. Additionally, the company has a 4% ownership interest in the Class A Properties in which it is generally entitled to 4% of the earnings or losses associated with these properties.
	Timberland Venture. In 2008, the company contributed 454,000 acres of timberlands located in its Southern Resources Segment to Southern Diversified Timber, LLC (“the Timberland Venture”) in exchange for a $705 million preferred interest and a 9% common interest valued at $78 million. The Timberland Venture’s other member, an affiliate of The Campbell Group LLC, contributed $783 million of cash in exchange for 91% of the Timberland Venture’s common interest. Following the contribution, the company borrowed $783 million from the Timberland Venture (“Note Payable to Timberland Venture”). The company accounts for its interest in the Timberland Venture under the equity method of accounting.
	The Timberland Venture is a variable interest entity. The primary operating activities of the Timberland Venture consist of owning timberlands and entering into cutting contracts with an affiliate of the other member. Besides quarterly interest payments on the Note Payable to Timberland Venture, the company has not provided financing or other support to the venture. The venture generates sufficient cash from operating activities to finance its operations.
	We are not the primary beneficiary of the Timberland Venture. The company does not manage the day-to-day operations of the Timberland Venture, has only limited protective rights and its involvement is generally limited to receiving distributions on its preferred and common interests. We are not the primary beneficiary because we do not direct the activities that most significantly impact the Timberland Venture’s economic performance. We believe that the activities that most significantly impact the Timberland Venture’s economic performance include managing the timberlands along with the timing and extent of the harvesting activities, neither of which we control.
	The carrying amount of the investment is $210 million at March 31, 2015 and $217 million at December 31, 2014, and it is reported in the Consolidated Balance Sheets as Equity Investment in Timberland Venture. Our maximum exposure to loss is $210 million, the carrying amount of the investment. Generally, losses are first allocated among the common interests based on positive capital accounts in which we hold a 9% common interest. No losses are allocated to our preferred interest ($705 million) until the common interests have absorbed losses of approximately $861 million.
PLUM CREEK TIMBERLANDS L P [Member]
Consolidation, Variable Interest Entity, Policy [Policy Text Block]	Variable Interest Entities
	Real Estate Development Ventures. MWV-Charleston Land Partners, LLC (“MWV-CLP”) is a variable interest entity. The primary activities of MWV-CLP are the active development of residential and commercial real estate on approximately 22,000 acres ("Class A Properties") and the identification, entitlement, marketing, and selling of approximately 71,000 acres of high-value rural and development-quality lands ("Class B Properties"). MWV-CLP is managed by an affiliate of MeadWestvaco Corporation ("MWV"). MWV-CLP is financed by regular capital calls from the manager of MWV-CLP in proportion to a member’s ownership interest. If a member does not make a capital contribution, the member’s ownership interest is diluted. The Operating Partnership made an initial capital contribution of $152 million in 2013. Also, during the years 2014 to 2020, the Operating Partnership agreed to make additional capital contributions of at least $48 million in connection with its interest in the Class B Properties, of which $37 million remained outstanding as of March 31, 2015. The Operating Partnership does not intend to provide any other sources of financing for MWV-CLP. The Operating Partnership accounts for its interest in MWV-CLP under the equity method of accounting.
	The Operating Partnership is not the primary beneficiary of MWV-CLP. The Operating Partnership considers the activities that most significantly impact the economic performance of MWV-CLP to be the day-to-day operating decisions along with the oversight responsibilities for the real estate development projects and properties. MWV has the power to direct the activities of MWV-CLP that most significantly impact its economic performance through its ability to manage the day-to-day operations of MWV-CLP. MWV also has the ability to control all management decisions associated with the 22,000 acres of the Class A Properties through its majority representation on the board of directors for the Class A Properties and its joint control of the Class B Properties due to its equal representation on the board of directors for the Class B Properties.
	The carrying amount of our investment in MWV-CLP is $125 million as of March 31, 2015 and $126 million as of December 31, 2014, and is reported in the Consolidated Balance Sheets as Equity Investment in Real Estate Development Ventures. Our maximum exposure to loss is $125 million, our carrying amount of our investment, plus any future capital contributions we elect to contribute to MWV-CLP. At a minimum, the Operating Partnership has agreed to make capital contributions in connection with its interest in Class B Properties of $37 million over the next six years. The Operating Partnership has a 50% ownership interest in the Class B Properties, and therefore, is entitled to 50% of the earnings or losses associated with these properties. Additionally, the Operating Partnership has a 4% ownership interest in the Class A Properties in which it is generally entitled to 4% of the earnings or losses associated with these properties.
	Timberland Venture. In 2008, a subsidiary of the Operating Partnership, Plum Creek Timber Operations I, LLC (“PC Member”), contributed 454,000 acres of timberlands located in its Southern Resources Segment to Southern Diversified Timber, LLC (“the Timberland Venture”) in exchange for a $705 million preferred interest and a 9% common interest valued at $78 million. The Timberland Venture’s other member, an affiliate of The Campbell Group LLC, contributed $783 million of cash in exchange for 91% of the Timberland Venture’s common interest. Following the formation of the Timberland Venture, Plum Creek Ventures I, LLC (“PC Ventures”), a 100% wholly-owned subsidiary of Plum Creek Timber Company, Inc., borrowed $783 million from the Timberland Venture. PC Ventures used the proceeds from the borrowing to make a $783 million capital contribution to the Operating Partnership. The Operating Partnership accounts for its interest in the Timberland Venture under the equity method of accounting.
	The Timberland Venture is a variable interest entity. The primary operating activities of the Timberland Venture consist of owning timberlands and entering into cutting contracts with an affiliate of the other member. Besides quarterly distributions to PC Ventures which it uses to fund interest payments on the loan owed by PC Ventures, the Operating Partnership has not provided financing or other support to the venture. The venture generates sufficient cash from operating activities to finance its operations.
	We are not the primary beneficiary of the Timberland Venture. PC Member does not manage the day-to-day operations of the Timberland Venture, has only limited protective rights and its involvement is generally limited to receiving distributions on its preferred and common interests. We are not the primary beneficiary because we do not direct the activities that most significantly impact the Timberland Venture’s economic performance. We believe that the activities that most significantly impact the Timberland Venture’s economic performance include managing the timberlands along with the timing and extent of the harvesting activities, neither of which we control.
	The carrying amount of the investment is $210 million at March 31, 2015 and $217 million at December 31, 2014, and it is reported in the Consolidated Balance Sheets as Equity Investment in Timberland Venture. Our maximum exposure to loss is $210 million, the carrying amount of the investment. Generally, losses are first allocated among the common interests based on positive capital accounts in which we hold a 9% common interest. No losses are allocated to our preferred interest ($705 million) until the common interests have absorbed losses of approximately $861 million.

Summarized_Income_Statement_In

Summarized Income Statement Information of the Timberland Venture	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Summarized Income Statement Information of Affiliate	Summarized Income Statement Information of the Timberland Venture
	The earnings of the Timberland Venture are a significant component of consolidated earnings. See Note 12 of the Notes to Consolidated Financial Statements. Equity earnings for the Timberland Venture were $23 million for the three-month period ending March 31, 2015 and were $15 million for the three-month period ending March 31, 2014. Equity earnings includes the amortization of the difference between the book value of the company’s investment and its proportionate share of the Timberland Venture’s net assets. For the three-month periods ended March 31, 2015 and March 31, 2014, amortization of basis difference was $10 million and $2 million, respectively. Furthermore, interest expense in connection with the loan from the Timberland Venture was $14 million for each of the three-month periods ended March 31, 2015 and 2014. The table below presents summarized income statement information for the Timberland Venture (in millions):
		Three Months Ended March 31,
		2015			2014
	Revenues	$	5		$	5
	Cost of Goods Sold (A)	4			5
	Selling, General and Administrative Expenses	2			1
	Operating Income (Loss)	(1		)	(1		)
	Interest Income, net	14			14
	Net Income before Allocation to Preferred and Common Interests	$	13		$	13
	(A)	Cost of Goods Sold includes Depreciation, Depletion and Amortization of $4 million and $5 million for the three-month periods ended March 31, 2015 and 2014, respectively.
PLUM CREEK TIMBERLANDS L P [Member]
Summarized Income Statement Information of Affiliate	Summarized Income Statement Information of the Timberland Venture
	The earnings of the Timberland Venture are a significant component of consolidated earnings. See Note 11 of the Notes to Consolidated Financial Statements. Equity earnings for the Timberland Venture were $23 million for the three-month period ending March 31, 2015 and were $15 million for the three-month period ending March 31, 2014. Equity earnings includes the amortization of the difference between the book value of the Operating Partnership’s investment and its proportionate share of the Timberland Venture’s net assets. For the three-month periods ended March 31, 2015 and March 31, 2014, amortization of basis difference was $10 million and $2 million, respectively. The table below presents summarized income statement information for the Timberland Venture (in millions):
		Three Months Ended March 31,
		2015			2014
	Revenues	$	5		$	5
	Cost of Goods Sold (A)	4			5
	Selling, General and Administrative Expenses	2			1
	Operating Income (Loss)	(1		)	(1		)
	Interest Income, net	14			14
	Net Income before Allocation to Preferred and Common Interests	$	13		$	13
	(A)	Cost of Goods Sold includes Depreciation, Depletion and Amortization of $4 million and $5 million for the three-month periods ended March 31, 2015 and 2014, respectively.

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Segment Information	Segment Information
	The tables below present information about reported segments for the quarterly periods ended March 31 (in millions):
		Northern			Southern			Real		Manufacturing		Energy and Natural Resources		Other(B)			Total(C)
		Resources			Resources			Estate(A)
	Quarter Ended March 31, 2015
	External Revenues	$	64		$	128		$	109	$	94	$	8	$	3		$	406
	Intersegment Revenues	6			—			—		—		—		—			6
	Depreciation, Depletion and Amortization	7			20			—		3		2		—			32
	Basis of Real Estate Sold	—			—			83		—		—		—			83
	Equity Earnings (Loss)	—			—			—		—		—		(1		)	(1		)
	Operating Income (Loss)	13			31			19		9		5		(1		)	76
	Quarter Ended March 31, 2014
	External Revenues	$	69		$	123		$	23	$	90	$	9	$	3		$	317
	Intersegment Revenues	8			—			—		—		—		—			8
	Depreciation, Depletion and Amortization	8			18			—		3		2		—			31
	Basis of Real Estate Sold	—			—			6		—		—		—			6
	Equity Earnings (Loss)	—			—			—		—		—		(1		)	(1		)
	Operating Income (Loss)	16			31			12		9		6		(1		)	73
	(A)	During the first quarter of 2015, the company closed the second phase of a two-phase transaction with The Nature Conservancy, selling approximately 117,000 acres in Montana for $85 million. The first phase of the transaction, a sale of approximately 48,000 acres in Washington, closed in 2014. The total sales price of $131 million was allocated among the Montana and Washington properties based on an external appraisal.
	(B)	For segment reporting, Equity Earnings (Loss) from Real Estate Development Ventures of $1 million for each of the quarterly periods ended March 31, 2015 and March 31, 2014 is included in Operating Income (Loss) for the Other Segment.
	(C)	Consolidated depreciation, depletion and amortization includes unallocated corporate expense of $1 million for each of the quarterly periods ended March 31, 2015 and March 31, 2014.
	A reconciliation of total segment operating income to income before income taxes is presented below for the quarterly periods ended March 31 (in millions):
		Quarter Ended March 31,
		2015			2014
	Total Segment Operating Income	$	76		$	73
	Corporate and Other Unallocated Expenses	(19		)	(18		)
	Other Unallocated Operating Income (Expense), net	3			1
	Equity Earnings from Timberland Venture	23			15
	Total Interest Expense, net	(41		)	(41		)
	Income before Income Taxes	$	42		$	30
PLUM CREEK TIMBERLANDS L P [Member]
Segment Information	Segment Information
	The tables below present information about reported segments for the quarterly periods ended March 31 (in millions):
		Northern			Southern			Real		Manufacturing		Energy and Natural Resources		Other(B)			Total(C)
		Resources			Resources			Estate(A)
	Quarter Ended March 31, 2015
	External Revenues	$	64		$	128		$	109	$	94	$	8	$	3		$	406
	Intersegment Revenues	6			—			—		—		—		—			6
	Depreciation, Depletion and Amortization	7			20			—		3		2		—			32
	Basis of Real Estate Sold	—			—			83		—		—		—			83
	Equity Earnings (Loss)	—			—			—		—		—		(1		)	(1		)
	Operating Income (Loss)	13			31			19		9		5		(1		)	76
	Quarter Ended March 31, 2014
	External Revenues	$	69		$	123		$	23	$	90	$	9	$	3		$	317
	Intersegment Revenues	8			—			—		—		—		—			8
	Depreciation, Depletion and Amortization	8			18			—		3		2		—			31
	Basis of Real Estate Sold	—			—			6		—		—		—			6
	Equity Earnings (Loss)	—			—			—		—		—		(1		)	(1		)
	Operating Income (Loss)	16			31			12		9		6		(1		)	73
	(A)	During the first quarter of 2015, the Operating Partnership closed the second phase of a two-phase transaction with The Nature Conservancy, selling approximately 117,000 acres in Montana for $85 million. The first phase of the transaction, a sale of approximately 48,000 acres in Washington, closed in 2014. The total sales price of $131 million was allocated among the Montana and Washington properties based on an external appraisal.
	(B)	For segment reporting, Equity Earnings (Loss) from Real Estate Development Ventures of $1 million for each of the quarterly periods ended March 31, 2015 and March 31, 2014 is included in Operating Income (Loss) for the Other Segment.
	(C)	Consolidated depreciation, depletion and amortization includes unallocated corporate expense of $1 million for each of the quarterly periods ended March 31, 2015 and March 31, 2014.
	A reconciliation of total segment operating income to income before income taxes is presented below for the quarterly periods ended March 31 (in millions):
		Quarter Ended March 31,
		2015			2014
	Total Segment Operating Income	$	76		$	73
	Corporate and Other Unallocated Expenses	(19		)	(18		)
	Other Unallocated Operating Income (Expense), net	3			1
	Equity Earnings from Timberland Venture	23			15
	Interest Expense, net	(27		)	(27		)
	Income before Income Taxes	$	56		$	44

Subsequent_Events

Subsequent Events (PLUM CREEK TIMBER CO INC [Member])	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Subsequent Events [Text Block]	Subsequent Events
	Quarterly Dividend. On May 5, 2015, the Board of Directors authorized the company to make a dividend payment of $0.44 per share, or approximately $77 million, which will be paid on May 29, 2015 to stockholders of record on May 15, 2015.

Supplemental_Disclosures

Supplemental Disclosures	3 Months Ended
	Mar. 31, 2015
Supplemental Disclosures Abstract
Supplemental Disclosures	FINANCIAL STATEMENTS (CONTINUED)
	Included in this item are the consolidated financial statements related to Plum Creek Timberlands, L.P., a Delaware Limited Partnership and a wholly-owned subsidiary of Plum Creek Timber Company, Inc. These financial statements are provided pursuant to Rule 3-10 of Regulation S-X in connection with the shelf registration statement on Form S-3 filed in November of 2014 pursuant to which Plum Creek Timberlands, L.P. has registered and from time to time may offer and sell debt securities. As of March 31, 2015, Plum Creek Timberlands, L.P. has publicly issued and outstanding $1,333 million aggregate principal amount of Senior Notes ("Public Debt") pursuant to the shelf registration statement.

Basis_of_Presentation_Accounti

Basis of Presentation (Accounting Policies) (PLUM CREEK TIMBERLANDS L P [Member])	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBERLANDS L P [Member]
Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block]	The consolidated financial statements of the Operating Partnership include the accounts of Plum Creek Timberlands, L.P. and its subsidiaries. The Operating Partnership is 100% owned by Plum Creek. Plum Creek has no assets or liabilities other than its direct and indirect ownership interests in Plum Creek Timberlands, L.P. and its interest in Plum Creek Ventures I, LLC (“PC Ventures”), a 100% owned subsidiary of Plum Creek. The Parent has no operations other than its investment in these subsidiaries and transactions in its own equity, such as the issuance and/or repurchase of common stock and the receipt of proceeds from stock option exercises. Intercompany transactions and accounts between Plum Creek Timberlands, L.P. and its subsidiaries have been eliminated in consolidation. All transactions are denominated in United States dollars.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following table sets forth the reconciliation of basic and diluted earnings per share for the quarterly periods ended March 31 (in millions, except per share amounts):
		Quarter Ended March 31,
		2015		2014
	Net Income Available to Common Stockholders	$	42	$	30
	Denominator for Basic Earnings per Share	175.9		177
	Effect of Dilutive Securities – Stock Options	0.3		0.2
	Effect of Dilutive Securities – Restricted Stock Units and Value Management Plan	—		0.1
	Denominator for Diluted Earnings per Share – Adjusted for Dilutive Securities	176.2		177.3
	Per Share Amounts:
	Net Income Per Share – Basic	$	0.24	$	0.17
	Net Income Per Share – Diluted	$	0.24	$	0.17

Inventories_Tables

Inventories (Tables)	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Inventory [Line Items]
Schedule of Inventory, Current [Table Text Block]	Inventories, accounted for using the lower of average cost or market, consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Raw Materials (primarily logs)	$	9	$	12
	Work-In-Process	3		3
	Finished Goods	32		31
		44		46
	Supplies	15		15
	Total	$	59	$	61
PLUM CREEK TIMBERLANDS L P [Member]
Inventory [Line Items]
Schedule of Inventory, Current [Table Text Block]	Inventories, accounted for using the lower of average cost or market, consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Raw Materials (primarily logs)	$	9	$	12
	Work-In-Process	3		3
	Finished Goods	32		31
		44		46
	Supplies	15		15
	Total	$	59	$	61

Timber_and_Timberlands_Tables

Timber and Timberlands (Tables)	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Timber and Timberlands [Line Items]
Timber and Timberlands Tables	Timber and Timberlands consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Timber and Logging Roads, net	$	2,494	$	2,518
	Timber Deeds, net	79		83
	Timberlands	1,385		1,408
	Timber and Timberlands, net	$	3,958	$	4,009
PLUM CREEK TIMBERLANDS L P [Member]
Timber and Timberlands [Line Items]
Timber and Timberlands Tables	Timber and Timberlands consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Timber and Logging Roads, net	$	2,494	$	2,518
	Timber Deeds, net	79		83
	Timberlands	1,385		1,408
	Timber and Timberlands, net	$	3,958	$	4,009

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	Property, Plant and Equipment consisted of the following (in millions):
		March 31, 2015			December 31, 2014
	Land, Buildings and Improvements	$	99		$	97
	Machinery and Equipment	331			331
		430			428
	Accumulated Depreciation	(312		)	(308		)
	Property, Plant and Equipment, net	$	118		$	120
PLUM CREEK TIMBERLANDS L P [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	Property, Plant and Equipment consisted of the following (in millions):
		March 31, 2015			December 31, 2014
	Land, Buildings and Improvements	$	99		$	97
	Machinery and Equipment	331			331
		430			428
	Accumulated Depreciation	(312		)	(308		)
	Property, Plant and Equipment, net	$	118		$	120

Borrowings_Tables

Borrowings (Tables)	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Debt Instrument [Line Items]
Debt	Debt consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Variable Rate Debt
	Term Credit Agreement (A)	$	225	$	225
	Revolving Line of Credit (B)	56		95
	Fixed Rate Debt
	Senior Notes	1,330		1,330
	Installment Note Payable	860		860
	Note Payable to Timberland Venture	783		783
	Total Debt	3,254		3,293
	Less:
	Current Portion of Long-Term Debt	439		439
	Line of Credit	56		95
	Long-Term Portion	$	2,759	$	2,759
	(A)	The company has a $225 million term credit agreement that matures on April 3, 2019. The interest rate on the $225 million term credit agreement was 1.68% and 1.67% as of March 31, 2015 and December 31, 2014, respectively. After giving effect to expected patronage distributions, the effective net interest rate on the term loan was approximately 1% as of both March 31, 2015 and December 31, 2014.
	(B)	The weighted-average interest rate for the borrowings on the line of credit was 1.36% and 1.34% as of March 31, 2015 and December 31, 2014, respectively. As of March 31, 2015, we had $56 million of borrowings and $2 million of standby letters of credit outstanding; $642 million remained available for borrowing under our $700 million line of credit. As of April 1, 2015, all of the borrowings under our line of credit were repaid.
PLUM CREEK TIMBERLANDS L P [Member]
Debt Instrument [Line Items]
Debt	Debt consisted of the following (in millions):
		March 31, 2015		December 31, 2014
	Variable Rate Debt
	Term Credit Agreement (A)	$	225	$	225
	Revolving Line of Credit (B)	56		95
	Fixed Rate Debt
	Senior Notes	1,330		1,330
	Installment Note Payable	860		860
	Total Debt	2,471		2,510
	Less:
	Current Portion of Long-Term Debt	439		439
	Line of Credit	56		95
	Long-Term Portion	$	1,976	$	1,976
	(A)	The Operating Partnership has a $225 million term credit agreement that matures on April 3, 2019. The interest rate on the $225 million term credit agreement was 1.68% and 1.67% as of March 31, 2015 and December 31, 2014, respectively. After giving effect to expected patronage distributions, the effective net interest rate on the term loan was approximately 1% as of both March 31, 2015 and December 31, 2014.
	(B)	The weighted-average interest rate for the borrowings on the line of credit was 1.36% and 1.34% as of March 31, 2015 and December 31, 2014, respectively. As of March 31, 2015, we had $56 million of borrowings and $2 million of standby letters of credit outstanding; $642 million remained available for borrowing under our $700 million line of credit. As of April 1, 2015, all of the borrowings under our line of credit were repaid.

Stockholders_Equity_Tables

Stockholders' Equity (Tables) (PLUM CREEK TIMBER CO INC [Member])	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Stockholders' Equity [Line Items]
Schedule of Stockholders Equity [Table Text Block]	The changes in the company’s stockholders’ equity accounts were as follows during 2015 (in millions):
		Common Stock										Retained							Accumulated
												Earnings (Accumulated Deficit)							Other
																			Comprehensive
		Shares			Dollars				Paid-in							Treasury			Income (Loss)			Total
									Capital							Stock						Equity
	January 1, 2015	175.9			$	2			$	2,955		$	(271	)		$	(992	)	$	(23	)	$	1,671
	Net Income											42										42
	Other Comprehensive Income (Loss)																		(1		)	(1		)
	Dividends											(77		)								(77		)
	Stock Option Exercises	—			—				1													1
	Shares Issued under Stock Incentive Plans	0.2			—				—													—
	Share-based Compensation								3													3
	Common Stock Repurchased	(0.5	)		—											(21		)				(21		)
	March 31, 2015	175.6			$	2			$	2,959		$	(306	)		$	(1,013	)	$	(24	)	$	1,618
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The changes in the company’s accumulated other comprehensive income (loss) by component, net of tax, were as follows during 2015 (in millions):
		Net Unrealized Holding Gain (Loss) (A)				Defined Benefit Plan Actuarial Net Loss (B)				Gain on Cash Flow Hedge			Total
	January 1, 2015	$	14			$	(42	)		$	5		$	(23	)
	Other Comprehensive Income (Loss) before Reclassifications	(1		)		—				—			(1		)
	Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(1		)		1				—			—
	31-Mar-15	$	12			$	(41	)		$	5		$	(24	)
	(A)    Unrealized holding gains were reclassified to Other Operating Income (Expense), net in the Consolidated
	Statements of Income when the related available for sale securities are sold.
	(B)    Amortization of actuarial gains and losses on the company's defined benefit pension plans is included in the
	computation of pension cost. See Note 10 of the Notes to Consolidated Financial Statements.

Partners_Capital_Tables

Partners' Capital (Tables) (PLUM CREEK TIMBERLANDS L P [Member])	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBERLANDS L P [Member]
Partners' Capital [Line Items]
Schedule Of Components Of Partners' Capital	The changes in the Operating Partnership’s capital accounts were as follows during 2015 (in millions):
		Preferred			Common			Accumulated			Total
		Partnership			Partners’			Other			Partnership
		Interest			Capital			Comprehensive			Capital
								Income (Loss)
	January 1, 2015	$	790		$	1,694		$	(23	)	$	2,461
	Net Income before Allocation to Series T-1 Preferred Interest and Partners				56						56
	Other Comprehensive Income (Loss)							(1		)	(1		)
	Net Income Allocation to Series T-1 Preferred Interest	14			(14		)				—
	Distributions to Partners (Common Partnership Interests)				(97		)				(97		)
	Distributions for Series T-1 Preferred Interest	(14		)							(14		)
	Capital Contributions from Parent				3						3
	March 31, 2015	$	790		$	1,642		$	(24	)	$	2,408
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The changes in the Operating Partnership's accumulated other comprehensive income (loss) by component, net of tax, were as follows during 2015 (in millions):
		Net Unrealized Holding Gain (Loss) (A)			Defined Benefit Plan Actuarial Net Loss (B)			Gain on Cash Flow Hedge			Total
	January 1, 2015	$	14		$	(42	)	$	5		$	(23	)
	Other Comprehensive Income (Loss) before Reclassifications	(1		)	—			—			(1		)
	Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(1		)	1			—			—
	31-Mar-15	$	12		$	(41	)	$	5		$	(24	)
	(A)    Unrealized holding gains were reclassified to Other Operating Income (Expense), net in the Consolidated
	Statements of Income when the related available for sale securities are sold.
	(B)    Amortization of actuarial gains and losses on the Operating Partnership's defined benefit pension plans is included in
	the computation of pension cost. See Note 9 of the Notes to Consolidated Financial Statements.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Level 1 Assets Reported in the Company's Financial Statements at Fair Value, Measured on a Recurring Basis	Assets and Liabilities Measured at Fair Value on a Recurring Basis. The company’s fair value measurements of its cash equivalents, available-for-sale securities, and trading securities, measured on a recurring basis, are categorized as Level 1 measurements under the fair value hierarchy in the Accounting Standards Codification. A Level 1 valuation is based on quoted prices in active markets at the measurement date for identical unrestricted assets or liabilities. Summarized below are the Level 1 assets reported in the company’s financial statements at fair value, measured on a recurring basis (in millions):
		Balance at			Fair Value Measurements
		31-Mar-15			at Reporting Date Using
					Quoted Prices in Active
					Markets of Identical Assets
					(Level 1 Measurements)
	Cash Equivalents (A)	$	91		$	91
	Available-for-Sale Securities (B)	43			43
	Trading Securities (B)	5			5
	Total	$	139		$	139
		Balance at			Fair Value Measurements
		31-Dec-14			at Reporting Date Using
					Quoted Prices in Active
					Markets of Identical Assets
					(Level 1 Measurements)
	Cash Equivalents (A)	$	90		$	90
	Available-for-Sale Securities (B)	43			43
	Trading Securities (B)	5			5
	Total	$	138		$	138
	(A)	Consists of several money market funds and is included in the $94 million and $92 million of Cash and Cash Equivalents in the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014, respectively.
	(B)	Consists of several mutual funds and is included in Investment in Grantor Trusts in the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014. At March 31, 2015, investments in these mutual funds were approximately 45% in domestic (U.S.) equities, 25% in international equities and 30% in debt securities.
Fair Value, Liabilities Measured on Recurring Basis [Table Text Block]	Other Instruments. Summarized below are the carrying amount and fair value of the company's debt (estimated using the discounted cash flow method) along with the categorization under the fair value hierarchy in the Accounting Standards Codification (in millions):
						Fair Value at March 31, 2015
			Carrying Amount at March 31, 2015			Quoted Prices		Significant		Significant		Total
						In Active		Observable		Unobservable
						Markets for		Inputs		Inputs
						Identical Assets		(Level 2)		(Level 3)
						(Level 1)
	Public Debt (A)		$	1,330		$	—	$	1,402	$	—	$	1,402
	Term Credit Agreement (B)		225			—		225		—		225
	Line of Credit (C)		56			—		56		—		56
	Installment Note Payable (D)		860			—		924		—		924
	Note Payable to Timberland Venture (E)		783			—		—		895		895
	Total Debt		$	3,254		$	—	$	2,607	$	895	$	3,502
						Fair Value at December 31, 2014
			Carrying Amount at			Quoted Prices		Significant		Significant		Total
			31-Dec-14			In Active		Observable		Unobservable
						Markets for		Inputs		Inputs
						Identical Assets		(Level 2)		(Level 3)
						(Level 1)
	Public Debt (A)		$	1,330		$	—	$	1,398	$	—	$	1,398
	Term Credit Agreement (B)		225			—		225		—		225
	Line of Credit (C)		95			—		95		—		95
	Installment Note Payable (D)		860			—		906		—		906
	Note Payable to Timberland Venture (E)		783			—		—		892		892
	Total Debt		$	3,293		$	—	$	2,624	$	892	$	3,516
	(A)	Fair value of the company's Public Debt (publicly issued Senior Notes) is estimated using multiple market quotes for the company's public bonds.
	(B)	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable debt.
	(C)	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable credit lines.
	(D)	Fair value is estimated by adjusting the spread over the applicable Treasury rate to a current market quote for comparable debt.
	(E)	Fair value is estimated by using market quotes for the company's Public Debt adjusted by an estimated risk premium for holding company debt and the different maturity.
PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Level 1 Assets Reported in the Company's Financial Statements at Fair Value, Measured on a Recurring Basis	Assets and Liabilities Measured at Fair Value on a Recurring Basis. The Operating Partnership’s fair value measurements of its cash equivalents, available-for-sale securities, and trading securities, measured on a recurring basis, are categorized as Level 1 measurements under the fair value hierarchy in the Accounting Standards Codification. A Level 1 valuation is based on quoted prices in active markets at the measurement date for identical unrestricted assets or liabilities. Summarized below are the Level 1 assets reported in the Operating Partnership’s financial statements at fair value, measured on a recurring basis (in millions):
		Balance at			Fair Value Measurements
		31-Mar-15			at Reporting Date Using
					Quoted Prices in Active
					Markets of Identical Assets
					(Level 1 Measurements)
	Cash Equivalents (A)	$	91		$	91
	Available-for-Sale Securities (B)	43			43
	Trading Securities (B)	5			5
	Total	$	139		$	139
		Balance at			Fair Value Measurements
		31-Dec-14			at Reporting Date Using
					Quoted Prices in Active
					Markets of Identical Assets
					(Level 1 Measurements)
	Cash Equivalents (A)	$	90		$	90
	Available-for-Sale Securities (B)	43			43
	Trading Securities (B)	5			5
	Total	$	138		$	138
	(A)	Consists of several money market funds and is included in the $94 million and $92 million of Cash and Cash Equivalents in the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014, respectively.
	(B)	Consists of several mutual funds and is included in Investment in Grantor Trusts in the Consolidated Balance Sheets at March 31, 2015 and December 31, 2014. At March 31, 2015, investments in these mutual funds were approximately 45% in domestic (U.S.) equities, 25% in international equities and 30% in debt securities.
Fair Value, Liabilities Measured on Recurring Basis [Table Text Block]	Other Instruments. Summarized below are the carrying amount and fair value of the Operating Partnership's debt (estimated using the discounted cash flow method) along with the categorization under the fair value hierarchy in the Accounting Standards Codification (in millions):
						Fair Value at March 31, 2015
			Carrying Amount at March 31, 2015			Quoted Prices		Significant		Significant		Total
						In Active		Observable		Unobservable
						Markets for		Inputs		Inputs
						Identical Assets		(Level 2)		(Level 3)
						(Level 1)
	Public Debt (A)		$	1,330		$	—	$	1,402	$	—	$	1,402
	Term Credit Agreement (B)		225			—		225		—		225
	Line of Credit (C)		56			—		56		—		56
	Installment Note Payable (D)		860			—		924		—		924
	Total Debt		$	2,471		$	—	$	2,607	$	—	$	2,607
						Fair Value at December 31, 2014
			Carrying Amount at			Quoted Prices		Significant		Significant		Total
			31-Dec-14			In Active		Observable		Unobservable
						Markets for		Inputs		Inputs
						Identical Assets		(Level 2)		(Level 3)
						(Level 1)
	Public Debt (A)		$	1,330		$	—	$	1,398	$	—	$	1,398
	Term Credit Agreement (B)		225			—		225		—		225
	Line of Credit (C)		95			—		95		—		95
	Installment Note Payable (D)		860			—		906		—		906
	Total Debt		$	2,510		$	—	$	2,624	$	—	$	2,624
	(A)	Fair value of the Operating Partnership's Public Debt (publicly issued Senior Notes) is estimated using multiple market quotes for the Operating Partnership's public bonds.
	(B)	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable debt.
	(C)	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable credit lines.
	(D)	Fair value is estimated by adjusting the spread over the applicable Treasury rate to a current market quote for comparable debt.

Employee_Pension_Plans_Tables

Employee Pension Plans (Tables)	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of Net Benefit Costs [Table Text Block]	The components of pension cost were as follows for the quarterly periods ended March 31 (in millions):
		Quarter Ended March 31,
		2015			2014
	Service Cost	$	2		$	2
	Interest Cost	2			2
	Expected Return on Plan Assets	(3		)	(2		)
	Recognized Actuarial Loss	1			—
	Total Pension Cost	$	2		$	2
PLUM CREEK TIMBERLANDS L P [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of Net Benefit Costs [Table Text Block]	The components of pension cost were as follows for the quarterly periods ended March 31 (in millions):
		Quarter Ended March 31,
		2015			2014
	Service Cost	$	2		$	2
	Interest Cost	2			2
	Expected Return on Plan Assets	(3		)	(2		)
	Recognized Actuarial Loss	1			—
	Total Pension Cost	$	2		$	2

Summarized_Income_Statement_In1

Summarized Income Statement Information of the Timberland Venture (Tables)	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments [Table Text Block]	The table below presents summarized income statement information for the Timberland Venture (in millions):
		Three Months Ended March 31,
		2015			2014
	Revenues	$	5		$	5
	Cost of Goods Sold (A)	4			5
	Selling, General and Administrative Expenses	2			1
	Operating Income (Loss)	(1		)	(1		)
	Interest Income, net	14			14
	Net Income before Allocation to Preferred and Common Interests	$	13		$	13
	(A)	Cost of Goods Sold includes Depreciation, Depletion and Amortization of $4 million and $5 million for the three-month periods ended March 31, 2015 and 2014, respectively.
PLUM CREEK TIMBERLANDS L P [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments [Table Text Block]	The table below presents summarized income statement information for the Timberland Venture (in millions):
		Three Months Ended March 31,
		2015			2014
	Revenues	$	5		$	5
	Cost of Goods Sold (A)	4			5
	Selling, General and Administrative Expenses	2			1
	Operating Income (Loss)	(1		)	(1		)
	Interest Income, net	14			14
	Net Income before Allocation to Preferred and Common Interests	$	13		$	13
	(A)	Cost of Goods Sold includes Depreciation, Depletion and Amortization of $4 million and $5 million for the three-month periods ended March 31, 2015 and 2014, respectively.

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2015
PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	The tables below present information about reported segments for the quarterly periods ended March 31 (in millions):
		Northern			Southern			Real		Manufacturing		Energy and Natural Resources		Other(B)			Total(C)
		Resources			Resources			Estate(A)
	Quarter Ended March 31, 2015
	External Revenues	$	64		$	128		$	109	$	94	$	8	$	3		$	406
	Intersegment Revenues	6			—			—		—		—		—			6
	Depreciation, Depletion and Amortization	7			20			—		3		2		—			32
	Basis of Real Estate Sold	—			—			83		—		—		—			83
	Equity Earnings (Loss)	—			—			—		—		—		(1		)	(1		)
	Operating Income (Loss)	13			31			19		9		5		(1		)	76
	Quarter Ended March 31, 2014
	External Revenues	$	69		$	123		$	23	$	90	$	9	$	3		$	317
	Intersegment Revenues	8			—			—		—		—		—			8
	Depreciation, Depletion and Amortization	8			18			—		3		2		—			31
	Basis of Real Estate Sold	—			—			6		—		—		—			6
	Equity Earnings (Loss)	—			—			—		—		—		(1		)	(1		)
	Operating Income (Loss)	16			31			12		9		6		(1		)	73
	(A)	During the first quarter of 2015, the company closed the second phase of a two-phase transaction with The Nature Conservancy, selling approximately 117,000 acres in Montana for $85 million. The first phase of the transaction, a sale of approximately 48,000 acres in Washington, closed in 2014. The total sales price of $131 million was allocated among the Montana and Washington properties based on an external appraisal.
	(B)	For segment reporting, Equity Earnings (Loss) from Real Estate Development Ventures of $1 million for each of the quarterly periods ended March 31, 2015 and March 31, 2014 is included in Operating Income (Loss) for the Other Segment.
	(C)	Consolidated depreciation, depletion and amortization includes unallocated corporate expense of $1 million for each of the quarterly periods ended March 31, 2015 and March 31, 2014
Reconciliation of Total Segment Operating Income to Consolidated Income Before Income Taxes	A reconciliation of total segment operating income to income before income taxes is presented below for the quarterly periods ended March 31 (in millions):
		Quarter Ended March 31,
		2015			2014
	Total Segment Operating Income	$	76		$	73
	Corporate and Other Unallocated Expenses	(19		)	(18		)
	Other Unallocated Operating Income (Expense), net	3			1
	Equity Earnings from Timberland Venture	23			15
	Total Interest Expense, net	(41		)	(41		)
	Income before Income Taxes	$	42		$	30
PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	The tables below present information about reported segments for the quarterly periods ended March 31 (in millions):
		Northern			Southern			Real		Manufacturing		Energy and Natural Resources		Other(B)			Total(C)
		Resources			Resources			Estate(A)
	Quarter Ended March 31, 2015
	External Revenues	$	64		$	128		$	109	$	94	$	8	$	3		$	406
	Intersegment Revenues	6			—			—		—		—		—			6
	Depreciation, Depletion and Amortization	7			20			—		3		2		—			32
	Basis of Real Estate Sold	—			—			83		—		—		—			83
	Equity Earnings (Loss)	—			—			—		—		—		(1		)	(1		)
	Operating Income (Loss)	13			31			19		9		5		(1		)	76
	Quarter Ended March 31, 2014
	External Revenues	$	69		$	123		$	23	$	90	$	9	$	3		$	317
	Intersegment Revenues	8			—			—		—		—		—			8
	Depreciation, Depletion and Amortization	8			18			—		3		2		—			31
	Basis of Real Estate Sold	—			—			6		—		—		—			6
	Equity Earnings (Loss)	—			—			—		—		—		(1		)	(1		)
	Operating Income (Loss)	16			31			12		9		6		(1		)	73
	(A)	During the first quarter of 2015, the Operating Partnership closed the second phase of a two-phase transaction with The Nature Conservancy, selling approximately 117,000 acres in Montana for $85 million. The first phase of the transaction, a sale of approximately 48,000 acres in Washington, closed in 2014. The total sales price of $131 million was allocated among the Montana and Washington properties based on an external appraisal.
	(B)	For segment reporting, Equity Earnings (Loss) from Real Estate Development Ventures of $1 million for each of the quarterly periods ended March 31, 2015 and March 31, 2014 is included in Operating Income (Loss) for the Other Segment.
	(C)	Consolidated depreciation, depletion and amortization includes unallocated corporate expense of $1 million for each of the quarterly periods ended March 31, 2015 and March 31, 2014.
Reconciliation of Total Segment Operating Income to Consolidated Income Before Income Taxes	A reconciliation of total segment operating income to income before income taxes is presented below for the quarterly periods ended March 31 (in millions):
		Quarter Ended March 31,
		2015			2014
	Total Segment Operating Income	$	76		$	73
	Corporate and Other Unallocated Expenses	(19		)	(18		)
	Other Unallocated Operating Income (Expense), net	3			1
	Equity Earnings from Timberland Venture	23			15
	Interest Expense, net	(27		)	(27		)
	Income before Income Taxes	$	56		$	44

Basis_of_Presentation_Narrativ

Basis of Presentation (Narrative) (Details)	Mar. 31, 2015
	acre
PLUM CREEK TIMBER CO INC [Member]
Basis of Presentation [Line Items]
Timber and Timberlands, net (acres)	6,400,000
Product conversion facilities owned in the Northwest United States	7
Higher and better use timberlands, which are expected to be sold and/or developed, acres	675,000
Land Expect To Sell For Recreational Uses In Acres	500,000
Land Expect To Sell For Conservation In Acres	100,000
Land Designated With Development Potential In Acres	75,000
Total acres of non-strategic timberlands	225,000
PLUM CREEK TIMBERLANDS L P [Member]
Basis of Presentation [Line Items]
Percentage Of Ownership	100.00%
Timber and Timberlands, net (acres)	6,400,000
Product conversion facilities owned in the Northwest United States	7
Higher and better use timberlands, which are expected to be sold and/or developed, acres	675,000
Land Expect To Sell For Recreational Uses In Acres	500,000
Land Expect To Sell For Conservation In Acres	100,000
Land Designated With Development Potential In Acres	75,000
Total acres of non-strategic timberlands	225,000

Earnings_Per_Share_Schedule_of

Earnings Per Share (Schedule of Basic and Diluted Earnings Per Share) (Details) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net Income Available to Common Stockholders	$42	$30
Denominator for Basic Earnings per Share	175.9	177
Effect of Dilutive Securities - Stock Options	0.3	0.2
Effect of Dilutive Securities - Restricted Stock Units and Value Management Plan	0	0.1
Denominator for Diluted Earnings per Share - Adjusted for Dilutive Securities	176.2	177.3
Net Income per Share-Basic	$0.24	$0.17
Net Income per Share-Diluted	$0.24	$0.17

Inventories_Details

Inventories (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
PLUM CREEK TIMBER CO INC [Member]
Inventory [Line Items]
Raw Materials (primarily logs)	$9	$12
Work-In-Process	3	3
Finished Goods	32	31
Inventory Raw Materials Finished Goods And Work In Process	44	46
Supplies	15	15
Total	59	61
PLUM CREEK TIMBERLANDS L P [Member]
Inventory [Line Items]
Raw Materials (primarily logs)	9	12
Work-In-Process	3	3
Finished Goods	32	31
Inventory Raw Materials Finished Goods And Work In Process	44	46
Supplies	15	15
Total	$59	$61

Timber_and_Timberlands_Timber_

Timber and Timberlands (Timber and Timberlands Table) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
PLUM CREEK TIMBER CO INC [Member]
Timber and Timberlands [Line Items]
Timber and Logging Roads, net	$2,494	$2,518
Timber Deeds, net	79	83
Timberlands	1,385	1,408
Timber and Timberlands, net	3,958	4,009
PLUM CREEK TIMBERLANDS L P [Member]
Timber and Timberlands [Line Items]
Timber and Logging Roads, net	2,494	2,518
Timber Deeds, net	79	83
Timberlands	1,385	1,408
Timber and Timberlands, net	$3,958	$4,009

Property_Plant_and_Equipment_P

Property, Plant and Equipment (Property, Plant and Equipment Table) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
PLUM CREEK TIMBER CO INC [Member]
Property, Plant and Equipment [Line Items]
Land, Buildings and Improvements	$99	$97
Machinery and Equipment	331	331
Property, Plant and Equipment, gross	430	428
Accumulated Depreciation	-312	-308
Property, Plant and Equipment, net	118	120
PLUM CREEK TIMBERLANDS L P [Member]
Property, Plant and Equipment [Line Items]
Land, Buildings and Improvements	99	97
Machinery and Equipment	331	331
Property, Plant and Equipment, gross	430	428
Accumulated Depreciation	-312	-308
Property, Plant and Equipment, net	$118	$120

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
PLUM CREEK TIMBER CO INC [Member]
Income Tax Examination [Line Items]
Tax Liability from Potential Adjustment	$100
Gain from Potential Tax Adjustment	600
Percentage of Gain Distributed in Common Stock	80.00%
PLUM CREEK TIMBERLANDS L P [Member]
Income Tax Examination [Line Items]
Tax Liability from Potential Adjustment	100
Gain from Potential Tax Adjustment	$600
Percentage of Gain Distributed in Common Stock	80.00%

Borrowings_Schedule_of_Debt_In

Borrowings (Schedule of Debt Information) (Details) (USD $)	3 Months Ended			1 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014	Apr. 30, 2015	Dec. 31, 2014		Dec. 31, 2008
PLUM CREEK TIMBER CO INC [Member]
Debt Instrument [Line Items]
Senior Notes	$1,330				$1,330
Installment Note Payable	860				860
Note Payable to Timberland Venture	783				783		783
Long-term Debt	3,254				3,293
Current Portion of Long-Term Debt	439				439
Line of Credit	56				95
Long Term Portion Of Total Borrowings	2,759				2,759
Line of Credit Facility, Decrease, Repayments	97		570
PLUM CREEK TIMBERLANDS L P [Member]
Debt Instrument [Line Items]
Senior Notes	1,330				1,330
Installment Note Payable	860				860
Long-term Debt	2,471				2,510
Current Portion of Long-Term Debt	439				439
Line of Credit	56				95
Long Term Portion Of Total Borrowings	1,976				1,976
Line of Credit Facility, Decrease, Repayments	97		570
Line of Credit [Member] | PLUM CREEK TIMBER CO INC [Member]
Debt Instrument [Line Items]
Line of Credit	56	[1]			95	[1]
Letters of Credit Outstanding, Amount	2
Line of Credit, Remained Available	642
Line of Credit Capacity	700
Debt, Weighted Average Interest Rate	1.36%				1.34%
Line of Credit [Member] | PLUM CREEK TIMBER CO INC [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Decrease, Repayments				56
Line of Credit [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Debt Instrument [Line Items]
Line of Credit	56	[1]			95	[1]
Letters of Credit Outstanding, Amount	2
Line of Credit, Remained Available	642
Line of Credit Capacity	700
Debt, Weighted Average Interest Rate	1.36%				1.34%
Line of Credit [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Decrease, Repayments				56
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBER CO INC [Member]
Debt Instrument [Line Items]
Long-term Debt	225	[2]			225	[2]
Term Credit Agreement, Interest	1.68%				1.67%
Effective Interest Rate, Percentage	1.00%				1.00%
Debt Instrument, Maturity Date	3-Apr-19
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Debt Instrument [Line Items]
Long-term Debt	$225	[3]			$225	[3]
Term Credit Agreement, Interest	1.68%				1.67%
Effective Interest Rate, Percentage	1.00%				1.00%
Debt Instrument, Maturity Date	3-Apr-19
[1]	The weighted-average interest rate for the borrowings on the line of credit was 1.36% and 1.34% as of MarchB 31, 2015 and DecemberB 31, 2014, respectively. As of MarchB 31, 2015, we had $56 million of borrowings and $2 million of standby letters of credit outstanding; $642 million remained available for borrowing under our $700 million line of credit. As of AprilB 1, 2015, all of the borrowings under our line of credit were repaid.
[2]	The company has a $225 million term credit agreement that matures on April 3, 2019. The interest rate on the $225 million term credit agreement was 1.68% and 1.67% as of MarchB 31, 2015 and DecemberB 31, 2014, respectively. After giving effect to expected patronage distributions, the effective net interest rate on the term loan was approximately 1% as of both MarchB 31, 2015 and DecemberB 31, 2014.
[3]	The Operating Partnership has a $225 million term credit agreement that matures on April 3, 2019. The interest rate on the $225 million term credit agreement was 1.68% and 1.67% as of MarchB 31, 2015 and DecemberB 31, 2014, respectively. After giving effect to expected patronage distributions, the effective net interest rate on the term loan was approximately 1% as of both MarchB 31, 2015 and DecemberB 31, 2014.

Stockholders_Equity_Schedule_O

Stockholders' Equity (Schedule Of Components Of Stockholders Equity) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$42	$30
PLUM CREEK TIMBER CO INC [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance Shares	175.9
Beginning Balance	1,671
Net Income	42	30
Other Comprehensive Income (Loss), net of tax	-1	1
Dividends	-77
Stock Option Exercises	1
Shares Issued under Stock Incentive Plans	0
Share-based Compensation	3
Common Stock Repurchased	-21
Ending Balance Shares	175.6
Ending Balance	1,618
Common Stock [Member] | PLUM CREEK TIMBER CO INC [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance Shares	175.9
Beginning Balance	2
Stock Option Exercises (in shares)	0
Stock Option Exercises	0
Shares Issued under Stock Incentive Plans (shares)	0.2
Shares Issued under Stock Incentive Plans	0
Stock Repurchased During Period, Shares	-0.5
Common Stock Repurchased	0
Ending Balance Shares	175.6
Ending Balance	2
Paid-in Capital [Member] | PLUM CREEK TIMBER CO INC [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	2,955
Stock Option Exercises	1
Shares Issued under Stock Incentive Plans	0
Share-based Compensation	3
Ending Balance	2,959
Retained Earnings (Accumulated Deficit) [Member] | PLUM CREEK TIMBER CO INC [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	-271
Net Income	42
Dividends	-77
Ending Balance	-306
Treasury Stock [Member] | PLUM CREEK TIMBER CO INC [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	-992
Common Stock Repurchased	-21
Ending Balance	-1,013
Accumulated Other Comprehensive Income (Loss) [Member] | PLUM CREEK TIMBER CO INC [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	-23
Other Comprehensive Income (Loss), net of tax	-1
Ending Balance	($24)

Stockholders_Equity_Accumulate

Stockholders' Equity Accumulated Other Comprehensive Income (Details) (PLUM CREEK TIMBER CO INC [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Stockholders' Equity [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	($24)		($23)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-1
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Stockholders' Equity [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	12		14
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-1
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-1	[1]
Accumulated Defined Benefit Plans Adjustment [Member]
Stockholders' Equity [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	-41		-42
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1	[2]
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Stockholders' Equity [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	5		5
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$0
[1]	Unrealized holding gains were reclassified to Other Operating Income (Expense), net in the Consolidated Statements of Income when the related available for sale securities are sold.
[2]	Amortization of actuarial gains and losses on the company's defined benefit pension plans is included in the computation of pension cost. See Note 10 of the Notes to Consolidated Financial Statements.

Partners_Capital_Schedule_Of_C

Partners' Capital (Schedule Of Components Of Partners' Capital) (Details) (PLUM CREEK TIMBERLANDS L P [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Partners' Capital [Line Items]
Beginning Balances	$2,461
Net Income before Allocation to Series T-1 Preferred Interest and Partners	56	44
Other Comprehensive Income (Loss), net of tax	-1	1
Net Income Allocation to Series T-1 Preferred Interest	0
Distributions to Partners (Common Partnership Interests)	-97	-79
Distributions for Series T-1 Preferred Interest	-14	-14
Capital Contributions from Parent	3
Ending Balances	2,408
Preferred Partnership Interest [Member]
Partners' Capital [Line Items]
Beginning Balances	790
Net Income Allocation to Series T-1 Preferred Interest	14
Distributions for Series T-1 Preferred Interest	-14
Ending Balances	790
Common Partners' Capital [Member]
Partners' Capital [Line Items]
Beginning Balances	1,694
Net Income before Allocation to Series T-1 Preferred Interest and Partners	56
Net Income Allocation to Series T-1 Preferred Interest	-14
Distributions to Partners (Common Partnership Interests)	-97
Capital Contributions from Parent	3
Ending Balances	1,642
Accumulated Other Comprehensive Income (Loss) [Member]
Partners' Capital [Line Items]
Beginning Balances	-23
Other Comprehensive Income (Loss), net of tax	-1
Ending Balances	($24)

Partners_Capital_Accumulated_O

Partners' Capital Accumulated Other Comprehensive Income (Details) (PLUM CREEK TIMBERLANDS L P [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Partners' Capital [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	($24)		($23)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-1
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Partners' Capital [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	12		14
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	-1
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-1	[1]
Accumulated Defined Benefit Plans Adjustment [Member]
Partners' Capital [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	-41		-42
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	1	[2]
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Partners' Capital [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	5		5
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$0
[1]	Unrealized holding gains were reclassified to Other Operating Income (Expense), net in the Consolidated Statements of Income when the related available for sale securities are sold.
[2]	Amortization of actuarial gains and losses on the Operating Partnership's defined benefit pension plans is included inthe computation of pension cost. See Note 9 of the Notes to Consolidated Financial Statements.

Fair_Value_Measurements_Level_

Fair Value Measurements (Level 1 Assets Reported in the Company's Financial Statements at Fair Value, Measured on a Recurring Basis) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	$94		$92		$104	$433
Domestic Portion of Mutual Funds (percentage)	45.00%
International Portion of Mutual Funds (percentage)	25.00%
Debt Securities Portion of Mutual Funds (percentage)	30.00%
PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	94		92		104	433
Domestic Portion of Mutual Funds (percentage)	45.00%
International Portion of Mutual Funds (percentage)	25.00%
Debt Securities Portion of Mutual Funds (percentage)	30.00%
Fair Value, Measurements, Recurring [Member] | PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	91	[1]	90	[1]
Available-for-Sale Securities	43	[2]	43	[2]
Trading Securities	5	[2]	5	[2]
Total	139		138
Fair Value, Measurements, Recurring [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	91	[1]	90	[1]
Available-for-Sale Securities	43	[2]	43	[2]
Trading Securities	5	[2]	5	[2]
Total	139		138
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	91	[1]	90	[1]
Available-for-Sale Securities	43	[2]	43	[2]
Trading Securities	5	[2]	5	[2]
Total	139		138
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	91	[1]	90	[1]
Available-for-Sale Securities	43	[2]	43	[2]
Trading Securities	5	[2]	5	[2]
Total	$139		$138
[1]	Consists of several money market funds and is included in the $94 million and $92 million of Cash and Cash Equivalents in the Consolidated Balance Sheets at MarchB 31, 2015 and DecemberB 31, 2014, respectively.
[2]	Consists of several mutual funds and is included in Investment in Grantor Trusts in the Consolidated Balance Sheets at MarchB 31, 2015 and DecemberB 31, 2014. At MarchB 31, 2015, investments in these mutual funds were approximately 45% in domestic (U.S.) equities, 25% in international equities and 30% in debt securities.

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$31	$31
PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Amortized Cost Basis	31	31
Categories of Investments, Marketable Securities, Trading Securities [Member] | PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Obligations Included in Other Liabilities	5	5
Categories of Investments, Marketable Securities, Trading Securities [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Compensation Obligations Included in Other Liabilities	$5	$5

Fair_Value_Measurements_Fair_V

Fair Value Measurements Fair Value, Liabilities Measured on a Recurring Basis (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014		Dec. 31, 2008
PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes	$1,330,000,000		$1,330,000,000
Debt Instrument, Fair Value Disclosure	3,502,000,000		3,516,000,000
Line of Credit, Current	56,000,000		95,000,000
Installment Note Payable	860,000,000		860,000,000
Note Payable to Timberland Venture	783,000,000		783,000,000		783,000,000
Long-term Debt	3,254,000,000		3,293,000,000
PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	2,607,000,000		2,624,000,000
PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	895,000,000		892,000,000
PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes	1,330,000,000		1,330,000,000
Debt Instrument, Fair Value Disclosure	2,607,000,000		2,624,000,000
Line of Credit, Current	56,000,000		95,000,000
Installment Note Payable	860,000,000		860,000,000
Long-term Debt	2,471,000,000		2,510,000,000
PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	2,607,000,000		2,624,000,000
PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Public Debt [Member] | PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes	1,330,000,000		1,330,000,000
Debt Instrument, Fair Value Disclosure	1,402,000,000		1,398,000,000
Public Debt [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Public Debt [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	1,402,000,000	[1]	1,398,000,000	[1]
Public Debt [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Public Debt [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior Notes	1,330,000,000		1,330,000,000
Debt Instrument, Fair Value Disclosure	1,402,000,000		1,398,000,000
Public Debt [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Public Debt [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	1,402,000,000	[2]	1,398,000,000	[2]
Public Debt [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	225,000,000		225,000,000
Long-term Debt	225,000,000	[3]	225,000,000	[3]
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	225,000,000	[4]	225,000,000	[4]
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	225,000,000		225,000,000
Long-term Debt	225,000,000	[5]	225,000,000	[5]
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	225,000,000	[4]	225,000,000	[4]
Term Credit Agreement 1 [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Line of Credit [Member] | PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of Credit, Current	56,000,000		95,000,000
Lines of Credit, Fair Value Disclosure	56,000,000		95,000,000
Line of Credit [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Lines of Credit, Fair Value Disclosure	0		0
Line of Credit [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Lines of Credit, Fair Value Disclosure	56,000,000	[6]	95,000,000	[6]
Line of Credit [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Lines of Credit, Fair Value Disclosure	0		0
Line of Credit [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of Credit, Current	56,000,000		95,000,000
Lines of Credit, Fair Value Disclosure	56,000,000		95,000,000
Line of Credit [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Lines of Credit, Fair Value Disclosure	0		0
Line of Credit [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Lines of Credit, Fair Value Disclosure	56,000,000	[6]	95,000,000	[6]
Line of Credit [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Lines of Credit, Fair Value Disclosure	0		0
Installment Note Payable [Member] | PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Installment Note Payable	860,000,000		860,000,000
Notes Payable, Fair Value Disclosure	924,000,000		906,000,000
Installment Note Payable [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes Payable, Fair Value Disclosure	0		0
Installment Note Payable [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes Payable, Fair Value Disclosure	924,000,000	[7]	906,000,000	[7]
Installment Note Payable [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes Payable, Fair Value Disclosure	0		0
Installment Note Payable [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Installment Note Payable	860,000,000		860,000,000
Notes Payable, Fair Value Disclosure	924,000,000		906,000,000
Installment Note Payable [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes Payable, Fair Value Disclosure	0		0
Installment Note Payable [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes Payable, Fair Value Disclosure	924,000,000	[7]	906,000,000	[7]
Installment Note Payable [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes Payable, Fair Value Disclosure	0		0
Note Payable to Timberland Venture [Member] | PLUM CREEK TIMBER CO INC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	895,000,000		892,000,000
Note Payable to Timberland Venture	783,000,000		783,000,000
Note Payable to Timberland Venture [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Note Payable to Timberland Venture [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	0		0
Note Payable to Timberland Venture [Member] | PLUM CREEK TIMBER CO INC [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	$895,000,000	[8]	$892,000,000	[8]
[1]	Fair value of the company's Public Debt (publicly issued Senior Notes) is estimated using multiple market quotes for the company's public bonds.
[2]	Fair value of the Operating Partnership's Public Debt (publicly issued Senior Notes) is estimated using multiple market quotes for the Operating Partnership's public bonds.
[3]	The company has a $225 million term credit agreement that matures on April 3, 2019. The interest rate on the $225 million term credit agreement was 1.68% and 1.67% as of MarchB 31, 2015 and DecemberB 31, 2014, respectively. After giving effect to expected patronage distributions, the effective net interest rate on the term loan was approximately 1% as of both MarchB 31, 2015 and DecemberB 31, 2014.
[4]	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable debt.
[5]	The Operating Partnership has a $225 million term credit agreement that matures on April 3, 2019. The interest rate on the $225 million term credit agreement was 1.68% and 1.67% as of MarchB 31, 2015 and DecemberB 31, 2014, respectively. After giving effect to expected patronage distributions, the effective net interest rate on the term loan was approximately 1% as of both MarchB 31, 2015 and DecemberB 31, 2014.
[6]	Fair value is estimated by adjusting the spread over LIBOR to a current market quote for comparable credit lines.
[7]	Fair value is estimated by adjusting the spread over the applicable Treasury rate to a current market quote for comparable debt.
[8]	Fair value is estimated by using market quotes for the company's Public Debt adjusted by an estimated risk premium for holding company debt and the different maturity.

Employee_Pension_Plans_Compone

Employee Pension Plans (Component of Pension Cost Recognized in Net Income) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
PLUM CREEK TIMBER CO INC [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$2	$2
Interest Cost	2	2
Expected Return on Plan Assets	-3	-2
Recognized Actuarial Loss	1	0
Total Pension Cost	2	2
PLUM CREEK TIMBERLANDS L P [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	2	2
Interest Cost	2	2
Expected Return on Plan Assets	-3	-2
Recognized Actuarial Loss	1	0
Total Pension Cost	$2	$2

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	12 Months Ended	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2008	Mar. 31, 2015	Dec. 31, 2013	Dec. 31, 2014
		acre
PLUM CREEK TIMBER CO INC [Member]
Variable Interest Entity [Line Items]
Land Designated With Development Potential In Acres		75,000
Equity Investment in Real Estate Development Ventures		$125		$126
Amount borrowed from the Timberland Venture	783	783		783
Equity Investment in Timberland Venture		210		217
PLUM CREEK TIMBERLANDS L P [Member]
Variable Interest Entity [Line Items]
Land Designated With Development Potential In Acres		75,000
Equity Investment in Real Estate Development Ventures		125		126
Proceeds from Partnership Contribution	783
Equity Investment in Timberland Venture		210		217
PC Ventures [Member]
Variable Interest Entity [Line Items]
Amount borrowed from the Timberland Venture	783
Variable Interest Entity, Not Primary Beneficiary [Member] | PLUM CREEK TIMBER CO INC [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss		210
Variable Interest Entity, Not Primary Beneficiary [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss		210
MWV-CLP (Class A Properties) [Member] | PLUM CREEK TIMBER CO INC [Member]
Variable Interest Entity [Line Items]
Land Designated With Development Potential In Acres		22,000
Equity Method Investment, Ownership Percentage		4.00%
MWV-CLP (Class A Properties) [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Variable Interest Entity [Line Items]
Land Designated With Development Potential In Acres		22,000
Equity Method Investment, Ownership Percentage		4.00%
MWV-CLP (Class B Properties) [Member] | PLUM CREEK TIMBER CO INC [Member]
Variable Interest Entity [Line Items]
Land Designated With Development Potential In Acres		71,000
Variable Interest Entity, Financial or Other Support, Amount			48
Additional Capital Contributions Outstanding		37
Variable Interest Entity, Financial or Other Support, Period Committed		6 years
Equity Method Investment, Ownership Percentage		50.00%
MWV-CLP (Class B Properties) [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Variable Interest Entity [Line Items]
Land Designated With Development Potential In Acres		71,000
Variable Interest Entity, Financial or Other Support, Amount			48
Additional Capital Contributions Outstanding		37
Variable Interest Entity, Financial or Other Support, Period Committed		6 years
Equity Method Investment, Ownership Percentage		50.00%
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member]
Variable Interest Entity [Line Items]
Payments to Acquire Equity Method Investments			152
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Variable Interest Entity [Line Items]
Payments to Acquire Equity Method Investments			152
MWV-CLP [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | PLUM CREEK TIMBER CO INC [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss		125
MWV-CLP [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss		125
Timberland Venture [Member] | PLUM CREEK TIMBER CO INC [Member]
Variable Interest Entity [Line Items]
Contributed Acres of Timberlands to Venture	454,000
Preferred Interest in Venture	705
Common Interest in Venture (Percent)	9.00%
Common Interest in Venture	78
Proceeds from Partnership Contribution	783
Other Partnership Ownership Percentage	91.00%
Total Common Interests in Venture		861
Timberland Venture [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Variable Interest Entity [Line Items]
Contributed Acres of Timberlands to Venture	454,000
Preferred Interest in Venture	705
Common Interest in Venture (Percent)	9.00%
Common Interest in Venture	78
Proceeds from Partnership Contribution	783
Other Partnership Ownership Percentage	91.00%
Total Common Interests in Venture		$861

Summarized_Income_Statement_In2

Summarized Income Statement Information of the Timberland Venture (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
PLUM CREEK TIMBER CO INC [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from Unconsolidated Entities	$22		$14
Amortization of Basis Difference	10		2
Interest Expense, Related Party	14		14
Revenues	5		5
Cost of Goods Sold	4	[1]	5	[1]
Selling, General and Administrative Expenses	2		1
Operating Income (Loss)	-1		-1
Interest Income, net	14		14
Net Income before Allocation to Preferred and Common Interests	13		13
Depreciation, Depletion and Amortization included in Cost of Goods Sold	4		5
PLUM CREEK TIMBERLANDS L P [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from Unconsolidated Entities	22		14
Amortization of Basis Difference	10		2
Revenues	5		5
Cost of Goods Sold	4	[1]	5	[1]
Selling, General and Administrative Expenses	2		1
Operating Income (Loss)	-1		-1
Interest Income, net	14		14
Net Income before Allocation to Preferred and Common Interests	13		13
Depreciation, Depletion and Amortization included in Cost of Goods Sold	4		5
Timberland Venture [Member] | PLUM CREEK TIMBER CO INC [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from Unconsolidated Entities	23		15
Timberland Venture [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from Unconsolidated Entities	$23		$15
[1]	Cost of Goods Sold includes Depreciation, Depletion and Amortization of $4 million and $5 million for the three-month periods ended MarchB 31, 2015 and 2014, respectively.

Segment_Information_Summary_of

Segment Information (Summary of Reported Segments) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
External Revenues	$406		$317
Depreciation, Depletion and Amortization	33		32
Basis of Real Estate Sold	83		6
Earnings from Unconsolidated Entities	22		14
Operating Income (Loss)	61		57
PLUM CREEK TIMBER CO INC [Member] | Northern Resources [Member]
Segment Reporting Information [Line Items]
External Revenues	64		69
Intersegment Revenues	6		8
Depreciation, Depletion and Amortization	7		8
Basis of Real Estate Sold	0		0
Operating Income (Loss)	13		16
PLUM CREEK TIMBER CO INC [Member] | Southern Resources [Member]
Segment Reporting Information [Line Items]
External Revenues	128		123
Intersegment Revenues	0		0
Depreciation, Depletion and Amortization	20		18
Basis of Real Estate Sold	0		0
Operating Income (Loss)	31		31
PLUM CREEK TIMBER CO INC [Member] | Real Estate [Member]
Segment Reporting Information [Line Items]
External Revenues	109	[1]	23	[1]
Intersegment Revenues	0	[1]	0	[1]
Depreciation, Depletion and Amortization	0	[1]	0	[1]
Basis of Real Estate Sold	83	[1]	6	[1]
Operating Income (Loss)	19	[1]	12	[1]
PLUM CREEK TIMBER CO INC [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
External Revenues	94		90
Intersegment Revenues	0		0
Depreciation, Depletion and Amortization	3		3
Basis of Real Estate Sold	0		0
Operating Income (Loss)	9		9
PLUM CREEK TIMBER CO INC [Member] | Energy and Natural Resources [Member]
Segment Reporting Information [Line Items]
External Revenues	8		9
Intersegment Revenues	0		0
Depreciation, Depletion and Amortization	2		2
Basis of Real Estate Sold	0		0
Operating Income (Loss)	5		6
PLUM CREEK TIMBER CO INC [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
External Revenues	3		3
Intersegment Revenues	0		0
Depreciation, Depletion and Amortization	0		0
Basis of Real Estate Sold	0		0
Operating Income (Loss)	-1	[2]	-1	[2]
PLUM CREEK TIMBER CO INC [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
External Revenues	406		317
Intersegment Revenues	6		8
Depreciation, Depletion and Amortization	32	[3]	31	[3]
Basis of Real Estate Sold	83		6
Operating Income (Loss)	76		73
PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
External Revenues	406		317
Depreciation, Depletion and Amortization	33		32
Basis of Real Estate Sold	83		6
Earnings from Unconsolidated Entities	22		14
Operating Income (Loss)	61		57
PLUM CREEK TIMBERLANDS L P [Member] | Northern Resources [Member]
Segment Reporting Information [Line Items]
External Revenues	64		69
Intersegment Revenues	6		8
Depreciation, Depletion and Amortization	7		8
Basis of Real Estate Sold	0		0
Operating Income (Loss)	13		16
PLUM CREEK TIMBERLANDS L P [Member] | Southern Resources [Member]
Segment Reporting Information [Line Items]
External Revenues	128		123
Intersegment Revenues	0		0
Depreciation, Depletion and Amortization	20		18
Basis of Real Estate Sold	0		0
Operating Income (Loss)	31		31
PLUM CREEK TIMBERLANDS L P [Member] | Real Estate [Member]
Segment Reporting Information [Line Items]
External Revenues	109	[4]	23	[4]
Intersegment Revenues	0	[4]	0	[4]
Depreciation, Depletion and Amortization	0	[4]	0	[4]
Basis of Real Estate Sold	83	[4]	6	[4]
Operating Income (Loss)	19	[4]	12	[4]
PLUM CREEK TIMBERLANDS L P [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
External Revenues	94		90
Intersegment Revenues	0		0
Depreciation, Depletion and Amortization	3		3
Basis of Real Estate Sold	0		0
Operating Income (Loss)	9		9
PLUM CREEK TIMBERLANDS L P [Member] | Energy and Natural Resources [Member]
Segment Reporting Information [Line Items]
External Revenues	8		9
Intersegment Revenues	0		0
Depreciation, Depletion and Amortization	2		2
Basis of Real Estate Sold	0		0
Operating Income (Loss)	5		6
PLUM CREEK TIMBERLANDS L P [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
External Revenues	3		3
Intersegment Revenues	0		0
Depreciation, Depletion and Amortization	0		0
Basis of Real Estate Sold	0		0
Operating Income (Loss)	-1	[2]	-1	[2]
PLUM CREEK TIMBERLANDS L P [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
External Revenues	406		317
Intersegment Revenues	6		8
Depreciation, Depletion and Amortization	32	[3]	31	[3]
Basis of Real Estate Sold	83		6
Operating Income (Loss)	76		73
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	-1		-1
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member] | Northern Resources [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0		0
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member] | Southern Resources [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0		0
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member] | Real Estate [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0	[1]	0	[1]
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0		0
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member] | Energy and Natural Resources [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0		0
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	-1	[2]	-1	[2]
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	-1		-1
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	-1		-1
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Northern Resources [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0		0
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Southern Resources [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0		0
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Real Estate [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0	[4]	0	[4]
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Manufacturing [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0		0
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Energy and Natural Resources [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	0		0
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	-1	[2]	-1	[2]
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	($1)		($1)
[1]	During the first quarter of 2015, the company closed the second phase of a two-phase transaction with The Nature Conservancy, selling approximately 117,000 acres in Montana for $85 million. The first phase of the transaction, a sale of approximately 48,000 acres in Washington, closed in 2014. The total sales price of $131 million was allocated among the Montana and Washington properties based on an external appraisal.
[2]	For segment reporting, Equity Earnings (Loss) from Real Estate Development Ventures of $1 million for each of the quarterly periods ended MarchB 31, 2015 and MarchB 31, 2014 is included in Operating Income (Loss) for the Other Segment.
[3]	Consolidated depreciation, depletion and amortization includes unallocated corporate expense of $1 million for each of the quarterly periods ended MarchB 31, 2015 and MarchB 31, 2014.
[4]	During the first quarter of 2015, the Operating Partnership closed the second phase of a two-phase transaction with The Nature Conservancy, selling approximately 117,000 acres in Montana for $85 million. The first phase of the transaction, a sale of approximately 48,000 acres in Washington, closed in 2014. The total sales price of $131 million was allocated among the Montana and Washington properties based on an external appraisal.

Segment_Information_Narrative_

Segment Information (Narrative) (Details) (USD $)	3 Months Ended				12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
					acre
PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Land Sales	$109		$23
Depreciation, Depletion and Amortization	33		32
Earnings from Unconsolidated Entities	-22		-14
PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Land Sales	109		23
Depreciation, Depletion and Amortization	33		32
Earnings from Unconsolidated Entities	-22		-14
Other Segments [Member] | PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization	0		0
Other Segments [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization	0		0
Corporate Segment [Member] | PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization	1		1
Corporate Segment [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization	1		1
MWV-CLP [Member] | PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	1		1
MWV-CLP [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	1		1
MWV-CLP [Member] | Other Segments [Member] | PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	1	[1]	1	[1]
MWV-CLP [Member] | Other Segments [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Earnings from Unconsolidated Entities	1	[1]	1	[1]
Montana TNC Sale [Member] | PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Land Dispositions (Acres)	117,000
Land Sales	85
Montana TNC Sale [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Land Dispositions (Acres)	117,000
Land Sales	85
Washington TNC Sale [Member] | PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Land Dispositions (Acres)					48,000
Washington TNC Sale [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Land Dispositions (Acres)					48,000
Total TNC Sale [Member] | PLUM CREEK TIMBER CO INC [Member]
Segment Reporting Information [Line Items]
Land Sales	131
Total TNC Sale [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting Information [Line Items]
Land Sales	$131
[1]	For segment reporting, Equity Earnings (Loss) from Real Estate Development Ventures of $1 million for each of the quarterly periods ended MarchB 31, 2015 and MarchB 31, 2014 is included in Operating Income (Loss) for the Other Segment.

Segment_Information_Reconcilia

Segment Information (Reconciliation of Total Segment Operating Income to Consolidated Income Before Income Taxes) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
PLUM CREEK TIMBER CO INC [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss)	$61	$57
Earnings from Unconsolidated Entities	22	14
Total Interest Expense, net	-41	-41
Income before Income Taxes	42	30
PLUM CREEK TIMBER CO INC [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss)	76	73
PLUM CREEK TIMBER CO INC [Member] | Corporate, Non-Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss)	-19	-18
PLUM CREEK TIMBER CO INC [Member] | Other Unallocated Operating Income Expense Net [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss)	3	1
PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss)	61	57
Earnings from Unconsolidated Entities	22	14
Total Interest Expense, net	-27	-27
Income before Income Taxes	56	44
PLUM CREEK TIMBERLANDS L P [Member] | Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss)	76	73
PLUM CREEK TIMBERLANDS L P [Member] | Corporate, Non-Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss)	-19	-18
PLUM CREEK TIMBERLANDS L P [Member] | Other Unallocated Operating Income Expense Net [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss)	3	1
Timberland Venture [Member] | PLUM CREEK TIMBER CO INC [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Earnings from Unconsolidated Entities	23	15
Timberland Venture [Member] | PLUM CREEK TIMBERLANDS L P [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Earnings from Unconsolidated Entities	$23	$15

Subsequent_Events_Details

Subsequent Events (Details) (Subsequent Event [Member], PLUM CREEK TIMBER CO INC [Member], USD $)	5-May-15
In Millions, except Per Share data, unless otherwise specified
Subsequent Event [Member] | PLUM CREEK TIMBER CO INC [Member]
Dividends Payable [Line Items]
Dividend Payment per Share	$0.44
Dividend Payment, Approximately	$77

Supplemental_Disclosures_Detai

Supplemental Disclosures (Details) (PLUM CREEK TIMBERLANDS L P [Member], USD $)	Mar. 31, 2015
In Millions, unless otherwise specified
PLUM CREEK TIMBERLANDS L P [Member]
Supplemental Disclosures [Line Items]
Senior Notes Short and Long Term Aggregate	$1,333