Segment Information (Reconciliation of Total Segment Operating Income to Consolidated Income Before Income Taxes) (Details) (USD $) In Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
PLUM CREEK TIMBER CO INC [Member] | Operating Segments [Member]
Operating Income	$ 77	[1]	$ 67	[1]	$ 152	[1]	$ 178	[1]
PLUM CREEK TIMBERLANDS L P [Member] | Operating Segments [Member]
Operating Income	77	[2]	67	[2]	152	[2]	178	[2]
PLUM CREEK TIMBER CO INC [Member] | Unallocated Amount to Segment [Member]
Operating Income	(14)		(12)		(30)		(28)
PLUM CREEK TIMBERLANDS L P [Member] | Unallocated Amount to Segment [Member]
Operating Income	(14)		(12)		(30)		(28)
PLUM CREEK TIMBER CO INC [Member] | Other Unallocated Operating Income Expense Net [Member]
Operating Income	0		1		1		1
PLUM CREEK TIMBERLANDS L P [Member] | Other Unallocated Operating Income Expense Net [Member]
Operating Income	0		1		1		1
PLUM CREEK TIMBER CO INC [Member]
Operating Income	63		56		123		151
Equity Earnings from Timberland Venture	16		15		30		29
Total Interest Expense, net	(35)		(34)		(70)		(68)
Income before Income Taxes	44		37		83		112
PLUM CREEK TIMBERLANDS L P [Member]
Operating Income	63		56		123		151
Equity Earnings from Timberland Venture	16		15		30		29
Total Interest Expense, net	(20)		(19)		(41)		(39)
Income before Income Taxes	$ 59		$ 52		$ 112		$ 141

[1] Consolidated depreciation, depletion and amortization includes unallocated corporate depreciation of $1 million and $1 million for each of the quarterly periods ended June 30, 2011 and June 30, 2010; and $2 million and $2 million for each of the six-month periods ended June 30, 2011 and June 30, 2010.

[2] Consolidated depreciation, depletion and amortization includes unallocated corporate depreciation of $1 million and $1 million for each of the quarterly periods ended June 30, 2011 and June 30, 2010; and $2 million and $2 million for each of the six-month periods ended June 30, 2011 and June 30, 2010