NET EARNINGS PER SHARE Additional Information (Detail) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 28, 2016 $ / shares	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2015 $ / shares	Sep. 30, 2016 USD ($) $ / shares shares	Sep. 30, 2015 $ / shares	Dec. 31, 2015 USD ($) shares	Jul. 01, 2016 shares
Basic earnings per share attributable to Weyerhaeuser shareholders | $ / shares		$ 0.30	$ 0.35	$ 0.64	$ 0.78
Diluted earnings per share attributable to Weyerhaeuser shareholders | $ / shares		$ 0.30	$ 0.35	$ 0.64	$ 0.77
Stock repurchase program, shares repurchased		9,775,873		67,816,810
Stock repurchase program, shares repurchased value | $		$ 306		$ 2,000
Stock repurchase program, authorized repurchase amount | $						$ 2,500
Stock repurchase program, remaining authorized repurchase amount | $		$ 500		$ 500
Preference shares conversion ratio							1.6929
Shares issued upon conversion of stock		23,200,000
Volume weighted average price per share | $ / shares	$ 29.54
Unsettled Share Repurchases [Member]
Stock repurchase program, shares repurchased				0		0
6.375 percent Mandatory Convertible Preference Shares, Series A
Preference shares, outstanding		0		0		13,799,711	13,700,000