REVENUE - Disaggregated Revenue (DETAIL) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 1,692	$ 1,883	$ 1,918	$ 1,667	$ 1,724	$ 1,818	$ 1,824	$ 1,691	$ 7,160	$ 7,057	$ 6,384
Europe
Disaggregation of Revenue [Line Items]
Net sales									1,209	1,209
Asia Pacific
Disaggregation of Revenue [Line Items]
Net sales									664	656
Rest of World
Disaggregation of Revenue [Line Items]
Net sales									511	545
Composites
Disaggregation of Revenue [Line Items]
Net sales									2,059	2,041
Composites | Europe
Disaggregation of Revenue [Line Items]
Net sales									572	590
Composites | Asia Pacific
Disaggregation of Revenue [Line Items]
Net sales									475	464
Composites | Rest of World
Disaggregation of Revenue [Line Items]
Net sales									129	126
Insulation
Disaggregation of Revenue [Line Items]
Net sales									2,668	2,720
Insulation | Europe
Disaggregation of Revenue [Line Items]
Net sales									625	605
Insulation | Asia Pacific
Disaggregation of Revenue [Line Items]
Net sales									176	178
Insulation | Rest of World
Disaggregation of Revenue [Line Items]
Net sales									297	322
Roofing
Disaggregation of Revenue [Line Items]
Net sales									2,634	2,492
Roofing | Europe
Disaggregation of Revenue [Line Items]
Net sales									13	14
Roofing | Asia Pacific
Disaggregation of Revenue [Line Items]
Net sales									13	15
Roofing | Rest of World
Disaggregation of Revenue [Line Items]
Net sales									90	103
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Net sales									(201)	(196)
Intersegment Eliminations | Europe
Disaggregation of Revenue [Line Items]
Net sales									(1)	0
Intersegment Eliminations | Asia Pacific
Disaggregation of Revenue [Line Items]
Net sales									0	(1)
Intersegment Eliminations | Rest of World
Disaggregation of Revenue [Line Items]
Net sales									(5)	(6)
Residential | United States
Disaggregation of Revenue [Line Items]
Net sales									3,376	3,275
Residential | Composites | United States
Disaggregation of Revenue [Line Items]
Net sales									269	263
Residential | Insulation | United States
Disaggregation of Revenue [Line Items]
Net sales									927	990
Residential | Roofing | United States
Disaggregation of Revenue [Line Items]
Net sales									2,375	2,199
Residential | Intersegment Eliminations | United States
Disaggregation of Revenue [Line Items]
Net sales									(195)	(177)
Commercial and Industrial Sector | United States
Disaggregation of Revenue [Line Items]
Net sales									1,400	1,372
Commercial and Industrial Sector | Composites | United States
Disaggregation of Revenue [Line Items]
Net sales									614	598
Commercial and Industrial Sector | Insulation | United States
Disaggregation of Revenue [Line Items]
Net sales									643	625
Commercial and Industrial Sector | Roofing | United States
Disaggregation of Revenue [Line Items]
Net sales									143	161
Commercial and Industrial Sector | Intersegment Eliminations | United States
Disaggregation of Revenue [Line Items]
Net sales									$ 0	$ (12)