Segments - UBBP (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Assets	$ 3,851	$ 3,869	$ 4,736
USG Boral Building Products
Segment Reporting Information [Line Items]
Net sales	1,200	1,052	1,003
Operating profit	160	133	124
Net income attributable to UBBP	117	99	96
Depreciation, depletion, and amortization	45	43	43
Capital expenditures	49	45	49
Assets	1,419	1,292	1,303
Geographic Areas, Long-Lived Assets [Abstract]
Long-Lived Assets:	710	653	680
USG Boral Building Products | Reportable geographical components | Australia
Segment Reporting Information [Line Items]
Net sales	431	381	345
Geographic Areas, Long-Lived Assets [Abstract]
Long-Lived Assets:	229	217	216
USG Boral Building Products | Reportable geographical components | South Korea
Segment Reporting Information [Line Items]
Net sales	287	223	200
Geographic Areas, Long-Lived Assets [Abstract]
Long-Lived Assets:	123	107	106
USG Boral Building Products | Reportable geographical components | Thailand
Segment Reporting Information [Line Items]
Net sales	150	141	145
Geographic Areas, Long-Lived Assets [Abstract]
Long-Lived Assets:	86	75	72
USG Boral Building Products | Reportable geographical components | China
Segment Reporting Information [Line Items]
Net sales	119	103	120
Geographic Areas, Long-Lived Assets [Abstract]
Long-Lived Assets:	101	97	116
USG Boral Building Products | Reportable geographical components | Oman
Geographic Areas, Long-Lived Assets [Abstract]
Long-Lived Assets:	85	86	103
USG Boral Building Products | Reportable geographical components | Other
Segment Reporting Information [Line Items]
Net sales	271	255	234
Geographic Areas, Long-Lived Assets [Abstract]
Long-Lived Assets:	86	71	67
USG Boral Building Products | Geographic transfers
Segment Reporting Information [Line Items]
Net sales	$ (58)	$ (51)	$ (41)