DISCONTINUED OPERATIONS - Components of the net gain on divestiture (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Common shares tendered (58,813,151 shares at $33.22 per share)		$ 0	$ 1,954	$ 0
Cash		$ 0	$ 707	$ 0
Common stock in exchange for the distribution of shares of Weyerhaeuser Real Estate Company (WRECO) to our shareholders	(59,000,000)	0	(58,813,151)	0
Share price of common shares tendered			$ 33.22
Real Estate Divestiture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Common shares tendered (58,813,151 shares at $33.22 per share)			$ 1,954
Cash	$ 707		707
Proceeds			2,661
Net book value of contributed assets			1,671
Transaction costs, net of reimbursement			18
Net book value of contributed assets and transaction costs, net of reimbursement			$ 1,689