Employee Retirement Plans - Components of Net Pension and Postretirement Benefit Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost of benefits earned	$ 50	$ 44	$ 45
Interest cost on projected benefit obligation	62	61	66
Expected return on plan assets	(97)	(93)	(89)
Settlement	0	25	35
Curtailment	0	0	0
Net amortization	31	22	22
Net pension & postretirement cost	46	59	79
Net actuarial (loss) gain	(14)	77	58
Net amortization	(31)	(22)	(22)
Settlement	0	(25)	(35)
Curtailment	0	0	0
Deferred currency exchange	(7)	4	2
Total recognized in other comprehensive income	(52)	34	3
Total recognized in net pension & postretirement cost and other comprehensive income	(6)	93	82
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost of benefits earned	2	2	2
Interest cost on projected benefit obligation	5	5	6
Expected return on plan assets	0	0	0
Settlement	0	0	0
Curtailment	0	0	(20)
Net amortization	(23)	(23)	(27)
Net pension & postretirement cost	(16)	(16)	(39)
Net actuarial (loss) gain	(15)	10	(6)
Net amortization	23	23	27
Settlement	0	0	0
Curtailment	0	0	20
Deferred currency exchange	(1)	1	(7)
Total recognized in other comprehensive income	7	34	34
Total recognized in net pension & postretirement cost and other comprehensive income	(9)	18	(5)
USG Corporation Pension Plan - L&W Supply | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement		25	26
Net pension & postretirement cost	(1)	(1)	7
USG Corporation Pension Plan - L&W Supply | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net pension & postretirement cost	$ (3)	$ (1)	(3)
USG Corporation Pension Plan - Other | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement			$ 9