Significant Accounting Policies - Consolidation and Presentation (Details)	Dec. 31, 2015	Dec. 31, 2014	Feb. 27, 2014
Knauf USG
Schedule of Equity Method Investments [Line Items]
Ownership percentage interest	50.00%
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Ownership percentage interest	50.00%	50.00%	50.00%
USG Boral Building Products | Co-venturer
Schedule of Equity Method Investments [Line Items]
Ownership percentage by joint venture partner			50.00%
Minimum
Schedule of Equity Method Investments [Line Items]
Ownership percentage interest	20.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Ownership percentage interest	50.00%