SELECTED QUARTERLY FINANCIAL INFORMATION (unaudited) - Key Quarterly Financial Data for the Last Two Years (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net sales	$ 1,823	$ 1,872	$ 1,808	$ 1,693	$ 1,596	$ 1,709	$ 1,655	$ 1,405	$ 7,196	$ 6,365	$ 5,246
Operating income from continuing operations	476	205	157	293	174	261	248	139	1,131	822	644
Earnings from continuing operations before income taxes	374	103	58	181	87	184	161	72	716	504	353
Net earnings	271	130	24	157	551	227	168	81	582	1,027	506
Net earnings attributable to Weyerhaeuser common shareholders	$ 271	$ 130	$ 24	$ 157	$ 551	$ 227	$ 157	$ 70	$ 582	$ 1,005	$ 462
Basic net earnings per share attributable to Weyerhaeuser common shareholders	$ 0.36	$ 0.17	$ 0.03	$ 0.21	$ 0.74	$ 0.30	$ 0.21	$ 0.11	$ 0.77	$ 1.40	$ 0.89
Diluted net earnings per share attributable to Weyerhaeuser common shareholders	0.36	0.17	0.03	0.21	0.73	0.30	0.21	0.11	0.77	1.39	0.89
Dividends paid per share	0.32	0.31	0.31	0.31	0.31	0.31	0.31	0.31	1.25	1.24	$ 1.20
Maximum
Market prices - high/low	36.92	34.46	35.50	34.37	33.28	33.17	32.56	31.38	36.92	33.28
Minimum
Market prices - high/low	$ 33.92	$ 30.95	$ 32.28	$ 29.88	$ 28.58	$ 29.52	$ 26.55	$ 22.06	$ 29.88	$ 22.06