REVENUE - Disaggregated Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Disaggregated revenue	$ 1,667	$ 1,691
Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	296	279
Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	149	142
Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	122	142
Composites
Disaggregation of Revenue [Line Items]
Disaggregated revenue	513	511
Composites | Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	150
Composites | Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	112
Composites | Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	30
Insulation
Disaggregation of Revenue [Line Items]
Disaggregated revenue	591	596
Insulation | Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	143
Insulation | Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	34
Insulation | Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	63
Roofing
Disaggregation of Revenue [Line Items]
Disaggregated revenue	614	642
Roofing | Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	4
Roofing | Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	3
Roofing | Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	31
Eliminations
Disaggregation of Revenue [Line Items]
Disaggregated revenue	(51)	(58)
Eliminations | Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	(1)
Eliminations | Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	0
Eliminations | Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	(2)
U.S. residential | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	766	804
U.S. residential | Composites | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	67
U.S. residential | Insulation | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	196
U.S. residential | Roofing | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	551
U.S. residential | Eliminations | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	(48)
U.S. commercial and industrial | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	334	$ 324
U.S. commercial and industrial | Composites | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	154
U.S. commercial and industrial | Insulation | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	155
U.S. commercial and industrial | Roofing | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	25
U.S. commercial and industrial | Eliminations | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	$ 0