Borrowings (Schedule of Debt and Parenthetical Information) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011		Dec. 31, 2010
PLUM CREEK TIMBER CO INC [Member] | Term Credit Agreement [Member]
Total Debt	$ 350	[1]	$ 350	[1]
Term Credit Agreement, Interest	0.57%
Debt Instrument, Maturity Date	Jun. 15, 2012
PLUM CREEK TIMBERLANDS L P [Member] | Term Credit Agreement [Member]
Total Debt	350	[1]	350	[1]
Term Credit Agreement, Interest	0.57%
Debt Instrument, Maturity Date	Jun. 15, 2012
PLUM CREEK TIMBER CO INC [Member] | Revolving Line of Credit [Member]
Line of Credit	227	[2]	166	[2]
Line of Credit, Weighted-Average Interest Rate	1.65%
Line of Credit Capacity	600
PLUM CREEK TIMBERLANDS L P [Member] | Revolving Line of Credit [Member]
Line of Credit	227	[2]	166	[2]
Line of Credit, Weighted-Average Interest Rate	1.65%
Line of Credit Capacity	600
PLUM CREEK TIMBER CO INC [Member]
Senior Notes	1,338		1,387
Note Payable to Timberland Venture	783		783
Total Debt	2,698		2,686
Current Portion of Long-Term Debt	395		94
Line of Credit	227		166
Long Term Portion Of Total Borrowings	2,076		2,426
Letter of Credit, Standby Outstanding	3
Line of Credit, Remained Available	370
PLUM CREEK TIMBERLANDS L P [Member]
Senior Notes	1,338		1,387
Total Debt	1,915		1,903
Current Portion of Long-Term Debt	395		94
Line of Credit	227		166
Long Term Portion Of Total Borrowings	1,293		1,643
Letter of Credit, Standby Outstanding	3
Line of Credit, Remained Available	$ 370

[1] As of June 30, 2011, the interest rate on the $350 million term credit agreement was 0.57%. This agreement matures June 15, 2012.

[2] As of June 30, 2011, the weighted-average interest rate for the borrowings on the line of credit was 1.65%. As of June 30, 2011, we had $227 million of borrowings and $3 million of standby letters of credit outstanding; $370 million remained available for borrowing under our $600 million line of credit. As of July 1, 2011, all of the borrowings outstanding under our line of credit were repaid.