CONDENSED CONSOLIDATING FINANCIAL INFORMATION Condensed Consolidating Financial Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Cash and Cash Equivalents, at Carrying Value, Including Discontinued Operations		$ 1,158	$ 1,012	$ 1,580
Net sales	$ 1,835	1,727
Cost of products sold	1,475	1,385
Gross margin	360	342
Other operating expenses, net	174	142
Operating income	186	200
Non-operating expense, net	(85)	(80)
Earnings before income taxes	101	120
Income taxes	20	19
Net earnings	81	101
Dividends on preference shares	(11)	(11)
Net earnings attributable to Weyerhaeuser common shareholders	70	90
Foreign currency translation adjustments	41	(47)
Actuarial gains, net of tax expense	10	62
Prior service costs, net of tax expense	(2)	(2)
Unrealized gains on available-for-sale securities	0	1
Total other comprehensive income	49	14
Comprehensive income (loss)	130	115
Cash and cash equivalents	415		1,012
Other current assets	1,415		1,162
Total current assets	1,830		2,174
Property and equipment, net	2,763		2,572
Timber and timberlands at cost, net	14,548		6,480
Investments in and advances to subsidiaries	0		0
Other assets	2,638		1,244
Total assets			12,470
Total current liabilities	984		875
Note payable to Timberland Venture	835		0
Long-term debt	7,803		4,875
Other long-term liabilities	1,876		1,851
Total liabilities	11,498		7,601
Mandatory convertible preference shares	14		14
Common shares	948		638
Other equity	9,319		4,217
Total equity	10,281		4,869
Total liabilities and equity	21,779		12,470
Net cash from (used in) operations	47	87
Capital expenditures	(73)	(89)
Acquisition of timberlands	(6)	(32)
Proceeds from sale of non-strategic assets	70	2
Issuance of note to parent		0
Distributions from joint ventures	24	0
Cash acquired in merger with Plum Creek	9	0
Distribution from subsidiaries	0	0
Net cash from (used in) investing activities	24	(119)
Net proceeds from issuance of debt	1,098	0
Payments on debt	(720)	0
Proceeds from note from subsidiary		0
Cash dividends on common shares	(241)	(152)
Repurchase of common stock	(798)	(253)
Distribution to parent	0	0
Other	(7)	15
Net cash from (used in) financing activities	(668)	(390)
Parent Company [Member]
Net sales	186	198
Cost of products sold	57	61
Gross margin	129	137
Other operating expenses, net	81	19
Operating income	48	118
Non-operating expense, net	(12)	(6)
Earnings before income taxes	36	112
Income taxes	0	0
Net earnings	36	112
Dividends on preference shares	(11)	(11)
Net earnings attributable to Weyerhaeuser common shareholders	25	101
Foreign currency translation adjustments	0	0
Actuarial gains, net of tax expense	2	5
Prior service costs, net of tax expense	0	0
Unrealized gains on available-for-sale securities	0	0
Total other comprehensive income	2	5
Comprehensive income (loss)	38	117
Cash and cash equivalents	216		673
Other current assets	54		7
Total current assets	270		680
Property and equipment, net	165		167
Timber and timberlands at cost, net	3,485		3,538
Investments in and advances to subsidiaries	10,896		2,948
Other assets	88		88
Total assets	14,904		7,421
Total current liabilities	141		66
Note payable to Timberland Venture	0
Long-term debt	2,743		1,645
Other long-term liabilities	91		91
Total liabilities	2,975		1,802
Mandatory convertible preference shares	14		14
Common shares	948		638
Other equity	10,967		4,967
Total equity	11,929		5,619
Total liabilities and equity	14,904		7,421
Net cash from (used in) operations	29	(50)
Capital expenditures	(14)	(19)
Acquisition of timberlands	0	(26)
Proceeds from sale of non-strategic assets	0	0
Issuance of note to parent		0
Distributions from joint ventures	0
Cash acquired in merger with Plum Creek	0
Distribution from subsidiaries	196	144
Net cash from (used in) investing activities	182	99
Net proceeds from issuance of debt	1,098
Payments on debt	(720)
Proceeds from note from subsidiary		600
Cash dividends on common shares	(241)	(152)
Repurchase of common stock	(798)	(253)
Distribution to parent	0	0
Other	(7)	11
Net cash from (used in) financing activities	(668)	206
Subsidiary Issuer [Member]
Guaranteed registered debt securities	894
Net sales	27	0
Cost of products sold	24	0
Gross margin	3	0
Other operating expenses, net	22	0
Operating income	(19)	0
Non-operating expense, net	(6)	0
Earnings before income taxes	(25)	0
Income taxes	0	0
Net earnings	(25)	0
Dividends on preference shares	0	0
Net earnings attributable to Weyerhaeuser common shareholders	(25)	0
Foreign currency translation adjustments	0	0
Actuarial gains, net of tax expense	0	0
Prior service costs, net of tax expense	0	0
Unrealized gains on available-for-sale securities	0	0
Total other comprehensive income	0	0
Comprehensive income (loss)	(25)	0
Cash and cash equivalents	29		0
Other current assets	7		0
Total current assets	36		0
Property and equipment, net	66		0
Timber and timberlands at cost, net	5,713		0
Investments in and advances to subsidiaries	4,535		0
Other assets	143		0
Total assets	10,493		0
Total current liabilities	59		0
Note payable to Timberland Venture	0
Long-term debt	1,829		0
Other long-term liabilities	67		0
Total liabilities	1,955		0
Mandatory convertible preference shares	0		0
Common shares	0		0
Other equity	8,538		0
Total equity	8,538		0
Total liabilities and equity	10,493		0
Net cash from (used in) operations	25	0
Capital expenditures	0	0
Acquisition of timberlands	0	0
Proceeds from sale of non-strategic assets	0	0
Issuance of note to parent		0
Distributions from joint ventures	0
Cash acquired in merger with Plum Creek	4
Distribution from subsidiaries	0	0
Net cash from (used in) investing activities	4	0
Net proceeds from issuance of debt	0
Payments on debt	0
Proceeds from note from subsidiary		0
Cash dividends on common shares	0	0
Repurchase of common stock	0	0
Distribution to parent	0	0
Other	0	0
Net cash from (used in) financing activities	0	0
Non-Guarantor Subsidiaries [Member]
Net sales	1,808	1,699
Cost of products sold	1,577	1,495
Gross margin	231	204
Other operating expenses, net	71	123
Operating income	160	81
Non-operating expense, net	(67)	(74)
Earnings before income taxes	93	7
Income taxes	(20)	(19)
Net earnings	73	(12)
Dividends on preference shares	0	0
Net earnings attributable to Weyerhaeuser common shareholders	73	(12)
Foreign currency translation adjustments	41	(47)
Actuarial gains, net of tax expense	8	57
Prior service costs, net of tax expense	(2)	(2)
Unrealized gains on available-for-sale securities	0	1
Total other comprehensive income	47	9
Comprehensive income (loss)	120	(3)
Cash and cash equivalents	170		339
Other current assets	1,359		1,161
Total current assets	1,529		1,500
Property and equipment, net	2,532		2,405
Timber and timberlands at cost, net	5,373		2,965
Investments in and advances to subsidiaries	781		0
Other assets	3,042		1,791
Total assets	13,257		8,661
Total current liabilities	785		814
Note payable to Timberland Venture	835
Long-term debt	3,831		3,830
Other long-term liabilities	1,718		1,760
Total liabilities	7,169		6,404
Mandatory convertible preference shares	0		0
Common shares	0		0
Other equity	6,088		2,257
Total equity	6,088		2,257
Total liabilities and equity	13,257		8,661
Net cash from (used in) operations	(7)	137
Capital expenditures	(59)	(70)
Acquisition of timberlands	(6)	(6)
Proceeds from sale of non-strategic assets	70	2
Issuance of note to parent		(600)
Distributions from joint ventures	24
Cash acquired in merger with Plum Creek	5
Distribution from subsidiaries	0	0
Net cash from (used in) investing activities	34	(674)
Net proceeds from issuance of debt	0
Payments on debt	0
Proceeds from note from subsidiary		0
Cash dividends on common shares	0	0
Repurchase of common stock	0	0
Distribution to parent	(196)	(144)
Other	0	4
Net cash from (used in) financing activities	(196)	(140)
Consolidation, Eliminations [Member]
Net sales	(186)	(170)
Cost of products sold	(183)	(171)
Gross margin	(3)	1
Other operating expenses, net	0	0
Operating income	(3)	1
Non-operating expense, net	0	0
Earnings before income taxes	(3)	1
Income taxes	0	0
Net earnings	(3)	1
Dividends on preference shares	0	0
Net earnings attributable to Weyerhaeuser common shareholders	(3)	1
Foreign currency translation adjustments	0	0
Actuarial gains, net of tax expense	0	0
Prior service costs, net of tax expense	0	0
Unrealized gains on available-for-sale securities	0	0
Total other comprehensive income	0	0
Comprehensive income (loss)	(3)	1
Cash and cash equivalents	0		0
Other current assets	(5)		(6)
Total current assets	(5)		(6)
Property and equipment, net	0		0
Timber and timberlands at cost, net	(23)		(23)
Investments in and advances to subsidiaries	(16,212)		(2,948)
Other assets	(635)		(635)
Total assets	(16,875)		(3,612)
Total current liabilities	(1)		(5)
Note payable to Timberland Venture	0
Long-term debt	(600)		(600)
Other long-term liabilities	0		0
Total liabilities	(601)		(605)
Mandatory convertible preference shares	0		0
Common shares	0		0
Other equity	(16,274)		(3,007)
Total equity	(16,274)		(3,007)
Total liabilities and equity	(16,875)		$ (3,612)
Net cash from (used in) operations	0	0
Capital expenditures	0	0
Acquisition of timberlands	0	0
Proceeds from sale of non-strategic assets	0	0
Issuance of note to parent		600
Distributions from joint ventures	0
Cash acquired in merger with Plum Creek	0
Distribution from subsidiaries	(196)	(144)
Net cash from (used in) investing activities	(196)	456
Net proceeds from issuance of debt	0
Payments on debt	0
Proceeds from note from subsidiary		(600)
Cash dividends on common shares	0	0
Repurchase of common stock	0	0
Distribution to parent	196	144
Other	0	0
Net cash from (used in) financing activities	$ 196	$ (456)