Selected Segment Data (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Revenues	$ 588.0	$ 811.0	$ 1,170.0	$ 1,502.0
Operating profit (loss):	23.0	215.0	45.0	342.0
Other operating credits and charges, net	3.0	5.0	1.0	5.0
Gain (loss) on sale or impairment of long-lived assets, net	(0.0)	0.0	(1.0)	1.0
General corporate and other expenses, net	8.0	6.0	16.0	12.0
Interest expense, net	(2.0)	0.0	(1.0)	(1.0)
Other non-operating items	(2.0)	(1.0)	9.0	(2.0)
Income from continuing operations before taxes	21.0	214.0	54.0	339.0
Provision for income taxes	3.0	51.0	11.0	81.0
Income from continuing operations attributed to LP	17.0	163.0	44.0	258.0
Siding [Member]
Segment Reporting Information [Line Items]
Revenues	238.0	262.0	474.0	489.0
Operating profit (loss):	37.0	53.0	70.0	89.0
OSB [Member]
Segment Reporting Information [Line Items]
Revenues	199.0	387.0	407.0	701.0
Operating profit (loss):	(18.0)	149.0	(25.0)	238.0
EWP [Member]
Segment Reporting Information [Line Items]
Revenues	107.0	113.0	197.0	219.0
Operating profit (loss):	6.0	6.0	9.0	6.0
South America [Member]
Segment Reporting Information [Line Items]
Revenues	40.0	45.0	85.0	88.0
Operating profit (loss):	7.0	10.0	15.0	19.0
Other [Member]
Segment Reporting Information [Line Items]
Revenues	5.0	3.0	10.0	6.0
Operating profit (loss):	(2.0)	(2.0)	(5.0)	(4.0)
Intersegment [Member]
Segment Reporting Information [Line Items]
Revenues	$ (2.0)	$ 0.0	$ (4.0)	$ 0.0