REVENUE - Disaggregated Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Disaggregated revenue	$ 1,918	$ 1,824	$ 3,585	$ 3,515
Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	314	326	610	605
Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	174	176	323	318
Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	133	133	255	275
Composites
Disaggregation of Revenue [Line Items]
Disaggregated revenue	535	541	1,048	1,052
Composites | Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	150	156	300	313
Composites | Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	119	122	231	228
Composites | Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	33	32	62	65
Insulation
Disaggregation of Revenue [Line Items]
Disaggregated revenue	661	682	1,252	1,278
Insulation | Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	161	166	304	285
Insulation | Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	52	51	86	84
Insulation | Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	73	79	136	154
Roofing
Disaggregation of Revenue [Line Items]
Disaggregated revenue	778	659	1,392	1,301
Roofing | Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	4	4	7	7
Roofing | Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	3	3	6	7
Roofing | Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	27	24	59	61
Eliminations
Disaggregation of Revenue [Line Items]
Disaggregated revenue	(56)	(58)	(107)	(116)
Eliminations | Europe
Disaggregation of Revenue [Line Items]
Disaggregated revenue	(1)	0	(1)	0
Eliminations | Asia-Pacific
Disaggregation of Revenue [Line Items]
Disaggregated revenue	0	0	0	(1)
Eliminations | Rest of world
Disaggregation of Revenue [Line Items]
Disaggregated revenue	0	(2)	(2)	(5)
U.S. residential | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	944	825	1,710	1,629
U.S. residential | Composites | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	75	75	142	151
U.S. residential | Insulation | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	217	226	413	448
U.S. residential | Roofing | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	707	578	1,258	1,137
U.S. residential | Eliminations | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	(55)	(54)	(103)	(107)
U.S. commercial and industrial | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	353	364	687	688
U.S. commercial and industrial | Composites | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	158	156	313	295
U.S. commercial and industrial | Insulation | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	158	160	313	307
U.S. commercial and industrial | Roofing | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	37	50	62	89
U.S. commercial and industrial | Eliminations | U.S.
Disaggregation of Revenue [Line Items]
Disaggregated revenue	$ 0	$ (2)	$ (1)	$ (3)