Segments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net Sales:
Net sales	$ 1,002	$ 970	$ 1,972	$ 1,879
Operating Profit (Loss):
Operating profit	133	105	260	181
Operating segments | Gypsum
Net Sales:
Net sales	635	617	1,270	1,194
Operating Profit (Loss):
Operating profit	113	98	224	166
Operating segments | Ceilings
Net Sales:
Net sales	137	131	262	254
Operating Profit (Loss):
Operating profit	33	25	62	46
Operating segments | Distribution
Net Sales:
Net sales	386	364	743	698
Operating Profit (Loss):
Operating profit	15	9	26	13
Corporate
Operating Profit (Loss):
Operating profit	(26)	(24)	(47)	(47)
Eliminations
Net Sales:
Net sales	(156)	(142)	(303)	(267)
Operating Profit (Loss):
Operating profit	$ (2)	$ (3)	$ (5)	$ 3