Usg (USG) 10-K 14 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	USG CORP
Entity Central Index Key	757,011
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 2,461,833,172
Entity Common Stock, Shares Outstanding		141,056,498

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 3,204	$ 3,017	$ 2,913
Cost of products sold	2,539	2,312	2,263
Gross profit	665	705	650
Selling and administrative expenses	298	304	302
Long-lived asset impairment charges	0	10	0
Recovery of receivable	0	(3)	(6)
Gain on disposal of shipping operations, net	0	0	(1)
Operating profit	367	394	355
Income from equity method investments	59	49	48
Interest expense	(69)	(145)	(163)
Interest income	4	4	2
Income and gain from the sale of equity method investment to related party	0	0	13
Loss on extinguishment of debt	(22)	(37)	(19)
Other (expense) income, net	(4)	9	0
Income from continuing operations before income taxes	335	274	236
Income tax (expense) benefit	(238)	(63)	740
Income from continuing operations	97	211	976
(Loss) income from discontinued operations, net of tax	(9)	20	15
Gain on sale of discontinued operations, net of tax	0	279	0
Net income	$ 88	$ 510	$ 991
Earnings per common share - basic:
Income from continuing operations (in dollars per share)	$ 0.67	$ 1.45	$ 6.70
(Loss) income from and gain on sale of discontinued operations (in dollars per share)	(0.06)	2.04	0.11
Net income (in dollars per share)	0.61	3.49	6.81
Earnings per common share - diluted:
Income from continuing operations (in dollars per share)	0.66	1.44	6.62
(Loss) income from and gain on sale of discontinued operations (in dollars per share)	(0.06)	2.02	0.11
Net income (in dollars per share)	$ 0.60	$ 3.46	$ 6.73
Average common shares (in shares)	144,447,488	145,929,506	145,457,208
Dilutive awards under long-term incentive plan (in shares)	2,263,358	1,731,473	1,624,866
Deferred shares for non-employee directors (in shares)	0	0	164,526
Average diluted common shares (in shares)	146,710,846	147,660,979	147,246,600

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 88	$ 510	$ 991
Derivatives qualifying as cash flow hedges:
(Loss) gain on derivatives qualifying as cash flow hedges, net of tax (benefit) of ($10), $2, and $4, respectively	(14)	1	(5)
Less: Reclassification adjustment for loss on derivatives included in net income, net of tax (benefit) of ($3), ($4), and $2, respectively	(3)	(6)	(9)
Derivatives qualifying as cash flow hedges, net of tax (benefit) of ($7), $6, and $2, respectively	(11)	7	4
Pension and postretirement benefits:
Changes in pension and postretirement benefits, net of tax (benefit) of ($27), ($19), and $6, respectively	(65)	(34)	74
Less: Amortization of prior service benefit cost included in net periodic benefit cost, net of tax (benefit) of ($10), ($7), and ($1), respectively	(14)	(9)	(7)
Pension and postretirement benefits, net of tax (benefit) of ($17), ($12), and $7, respectively	(51)	(25)	81
Foreign currency translation:
Changes in foreign currency translation, net of tax of $0 in all periods	58	(53)	(67)
Less: Translation loss realized upon sale of foreign entities, net of tax of $0 in all periods	0	0	(6)
Foreign currency translation, net of tax of $0 in all periods	58	(53)	(61)
Other comprehensive (loss) income, net of tax	(4)	(71)	24
Comprehensive income	$ 84	$ 439	$ 1,015

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivatives qualifying as cash flow hedges:
Gain (loss) on derivatives qualifying as cash flow hedges, tax (benefit)	$ (10)	$ 2	$ 4
Less: Reclassification adjustment for gain (loss) on derivatives included in net income, tax (benefit)	(3)	(4)	2
Derivatives qualifying as cash flow hedges, tax (benefit)	(7)	6	2
Pension and postretirement benefits:
Changes in pension and postretirement benefits, tax (benefit)	(27)	(19)	6
Less: Amortization of prior service benefit (cost) included in net periodic pension cost, tax (benefit)	(10)	(7)	(1)
Pension and postretirement benefits, tax benefit	(17)	(12)	7
Foreign currency translation:
Changes in foreign currency translation, tax (benefit)	0	0	0
Less: Translation gains realized upon sale of foreign entities, tax (benefit)	0	0	0
Foreign currency translation, tax (benefit)	$ 0	$ 0	$ 0

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 394	$ 427
Short-term marketable securities	62	62
Receivables (net of reserves: 2017 - $9 and 2016 - $8)	233	183
Inventories	252	236
Income taxes receivable	15	1
Other current assets	35	40
Total current assets	991	949
Long-term marketable securities	37	29
Property, plant and equipment, net	1,762	1,707
Deferred income taxes	287	492
Equity method investments	686	628
Goodwill and intangible assets	43	8
Other assets	45	56
Total assets	3,851	3,869
Liabilities and Stockholders’ Equity
Accounts payable	280	237
Accrued expenses	135	175
Income taxes payable	0	10
Total current liabilities	415	422
Long-term debt	1,078	1,083
Deferred income taxes	4	4
Pension and other postretirement benefits	326	290
Other liabilities	183	184
Total liabilities	2,006	1,983
Stockholders’ Equity:
Preferred stock – $1 par value, authorized 36,000,000 shares; outstanding - none	0	0
Common stock – $0.10 par value; authorized 200,000,000 shares; issued: 2017 - 146,513,000 shares and 2016 - 146,167,000 shares	15	15
Treasury stock at cost; 2017 - 5,571,000 shares and 2016 - 0 shares	(169)	0
Additional paid-in capital	3,057	3,038
Accumulated other comprehensive loss	(389)	(385)
Retained earnings (accumulated deficit)	(669)	(782)
Total stockholders’ equity	1,845	1,886
Total liabilities and stockholders’ equity	$ 3,851	$ 3,869

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Reserves on receivables	$ 9	$ 8
Preferred stock - par value (in dollars per share)	$ 1	$ 1
Preferred stock - authorized shares (in shares)	36,000,000	36,000,000
Preferred stock - outstanding shares (in shares)	0	0
Common stock - par value (in dollars per share)	$ 0.1	$ 0.1
Common stock - authorized shares (in shares)	200,000,000	200,000,000
Common stock - issued shares (in shares)	146,513,000	146,167,000
Treasury stock, shares (in shares)	5,571,000	0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities
Net income	$ 88	$ 510	$ 991
(Loss) income from discontinued operations, net of tax	(9)	20	15
Gain on sale of discontinued operations, net of tax	0	279	0
Income from continuing operations	97	211	976
Adjustments to reconcile income from continuing operations to net cash:
Depreciation, depletion, and amortization	132	134	131
Loss on extinguishment of debt	22	37	19
Long-lived asset impairment charges	0	10	0
Recovery of receivable	0	(3)	(6)
Share-based compensation expense	18	18	14
Deferred income taxes	255	57	(742)
(Loss) gain on asset dispositions	1	(9)	(13)
Gain from the sale of equity method investment to related party	0	0	(6)
Income from equity method investments	(59)	(49)	(50)
Dividends received from equity method investments	42	47	38
Pension settlement	12	20	1
(Increase) decrease in working capital
Receivables	(32)	6	21
Income taxes receivable	(12)	3	(3)
Inventories	(13)	(20)	(16)
Other current assets	(3)	9	1
Payables	20	21	(16)
Accrued expenses	(36)	(39)	(61)
Decrease in other assets	4	0	4
Decrease in pension and other postretirement benefits	(57)	(142)	(28)
Decrease in other liabilities	(13)	(6)	(7)
Other, net	4	9	22
Net cash provided by operating activities of continuing operations	382	314	279
Net cash provided by operating activities of discontinued operations	0	59	52
Net cash provided by operating activities of continuing operations	382	373	331
Investing Activities
Purchases of marketable securities	(105)	(274)	(246)
Sales or maturities of marketable securities	97	413	170
Capital expenditures	(168)	(83)	(87)
Proceeds from asset dispositions	2	12	58
Net proceeds from the sale of equity method investment to related party	0	0	52
Acquisition of business	(52)	0	0
Return of capital	0	1	0
Insurance proceeds	1	1	0
Return (deposit) of restricted cash	0	9	(8)
Net cash (used for) provided by investing activities of continuing operations	(225)	79	(61)
Net cash provided by (used for) investing activities of discontinued operations	6	667	(2)
Net cash (used for) provided by investing activities of continuing operations	(219)	746	(63)
Financing Activities
Issuance of debt	500	0	350
Repayment of debt	(521)	(1,131)	(386)
Payment of debt issuance fees	(8)	0	(6)
Issuance of common stock	15	4	6
Repurchase of common stock	(184)	0	0
Repurchases of common stock to satisfy employee tax withholding obligations	(4)	(2)	(8)
Net cash used for financing activities of continuing operations	(202)	(1,129)	(44)
Effect of exchange rate changes on cash	6	(5)	(10)
Net (decrease) increase in cash and cash equivalents from continuing operations	(39)	(741)	164
Net increase in cash and cash equivalents from discontinued operations	6	726	50
Change in cash balance included in discontinued operations	0	0	(3)
Net (decrease) increase in cash and cash equivalents	(33)	(15)	211
Cash and cash equivalents at beginning of period	427	442	231
Cash and cash equivalents at end of period	394	427	442
Supplemental Cash Flow Disclosures:
Interest paid, net of interest capitalized	82	153	158
Income taxes paid, net of refunds received	10	4	0
Noncash Investing and Financing Activities:
Amount in accounts payable for capital expenditures	18	15	5
Reversal of USG Boral Building Products earnout	$ 0	$ (24)	$ 0

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Deficit)	Stockholders' Equity	Non-controlling Interest
Balance at beginning of period at Dec. 31, 2014	$ 408	$ 14	$ 0	$ 3,014	$ (338)	$ (2,283)	$ 407	$ 1
Balance at beginning of period (in shares) at Dec. 31, 2014		144,768	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	991					991	991
Other comprehensive income (loss)	24				24		24
Share-based compensation	15			15			15
Stock issuances	7	$ 1	$ 8	(2)			7
Stock issuances (in shares)		899	283
Repurchase of common stock	(8)		$ (8)				(8)
Repurchase of common stock (in shares)			(283)
Changes in noncontrolling interest	(1)						0	(1)
Balance at end of period at Dec. 31, 2015	1,436	$ 15	$ 0	3,027	(314)	(1,292)	1,436	0
Balance at end of period (in shares) at Dec. 31, 2015		145,667	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	510					510	510
Other comprehensive income (loss)	(71)				(71)		(71)
Share-based compensation	18			18			18
Tax deficiencies in share-based compensation	(11)			(11)			(11)
Stock issuances	6	$ 0	$ 2	4			6
Stock issuances (in shares)		500	85
Repurchase of common stock	(2)		$ (2)				(2)
Repurchase of common stock (in shares)			(85)
Balance at end of period at Dec. 31, 2016	1,886	$ 15	$ 0	3,038	(385)	(782)	1,886	0
Balance at end of period (in shares) at Dec. 31, 2016		146,167	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Impact due to adoption of ASU 2016-09	25					25	25
Net income	88					88	88
Other comprehensive income (loss)	(4)				(4)		(4)
Share-based compensation	18			18			18
Stock issuances	14	$ 0	$ 19	(5)			14
Stock issuances (in shares)		346	577
Repurchase of common stock	(188)		$ (188)				(188)
Repurchase of common stock (in shares)			(6,148)
Other	6			6			6
Balance at end of period at Dec. 31, 2017	$ 1,845	$ 15	$ (169)	$ 3,057	$ (389)	$ (669)	$ 1,845	$ 0
Balance at end of period (in shares) at Dec. 31, 2017		146,513	(5,571)

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Nature of Operations USG, through our subsidiaries and joint ventures, is a leading manufacturer of building materials and innovative solutions. We produce a wide range of products for use in new residential, new nonresidential, and residential and nonresidential repair and remodel construction as well as products used in certain industrial processes. Our products are distributed through building materials dealers, home improvement centers and other retailers and specialty wallboard distributors and sold directly to contractors. Segments During the fourth quarter of 2017, we realigned our operating structure to reflect changes in our organizational structure and management's operation and view of our businesses. Our realigned operating structure is generally aligned by product type and consists of three divisions, in addition to our USG Boral Building Products, or UBBP, our joint ventures in Asia, Australasia and the Middle East: Gypsum, Performance Materials and Ceilings. The operations of the divisions are similar throughout North America. This change to our operating structure modified how the business is managed and the financial information received by the chief operating decision maker to assess operating performance and allocate resources, and thus, triggered a review of our segment structure. Effective for the quarter ended December 31, 2017, we changed the composition of our reportable segments to reflect this change. We now have five reportable segments: U.S. Wallboard and Surfaces, U.S. Performance Materials, U.S. Ceilings, Canada, and UBBP. Our prior period results have been recast to reflect these changes and present comparative year over year information by segment. See Note 14 , Segments. Our reportable segments are determined considering both qualitative and quantitative metrics for aggregation of the product type within geographies for which discrete financial information is available. Our U.S. Wallboard and Surfaces, U.S. Performance Materials and U.S. Ceilings reportable segments were identified based on products manufactured and marketed. Our Canada segment is a separately reportable segment, as while it has similar qualitative factors to U.S. operations, it has different quantitative metrics and, therefore, cannot be aggregated. Our operating segments in Mexico and Latin America, as well as our mining operation in Little Narrows, Nova Scotia, Canada, which we indefinitely idled in 2016, and our shipping company, which we exited in 2015, are now included in Other as reconciling items to our consolidated segments. There has been no change to our UBBP segment. Consolidation and Presentation Our consolidated financial statements include the accounts of USG Corporation and its majority-owned subsidiaries. Entities in which we have more than a 20% but not more than 50% ownership interest are accounted for using the equity method of accounting. All intercompany balances and transactions are eliminated in consolidation. Certain other reclassifications have been made to prior year amounts in order to conform with current year presentation. On our consolidated balance sheet, we reclassified the balance of our intangible assets from '"Other assets" to "Goodwill and intangible assets." Use of Estimates The preparation of our consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets, liabilities, revenues and expenses. Actual results could differ from these estimates. Revenue Recognition We recognize revenue when shipment is received by the customer. We enter into agreements with customers to offer rebates, generally based on achievement of specified sales levels and various marketing allowances that are common industry practice. Estimated reductions to revenue for customer programs and incentive offerings, including promotions and other volume–based incentives, are recorded in the period in which the sale occurs. Provisions for early payment discounts are accrued in the same period in which the sale occurs. Shipping and Handling Costs Shipping and handling costs billed to customers are included in net sales and the related costs are presented in cost of products sold. Advertising Advertising expenses consist of media advertising and related production costs and sponsorships. We charge advertising expenses to earnings as incurred. These expenses amounted to $ 10 million , $ 12 million and $16 million for the years ended December 31, 2017 , 2016 and 2015 , respectively, and are included in "Selling and administrative expenses" in our consolidated statements of income. Research and Development We charge research and development expenditures to earnings as incurred. These expenditures amounted to $23 million , $24 million and $23 million for the years ended December 31, 2017 , 2016 and 2015 , respectively, and are included in "Cost of products sold" and "Selling and administrative expenses" in our consolidated statements of income. Legal Costs We expense legal costs as incurred. Income Taxes We record income tax expense (benefit) under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized based on temporary differences between the financial statement carrying values of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply in the years in which the temporary differences are expected to be recovered or paid. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in earnings in the period when the change is enacted. Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not that a tax benefit will not be realized. A reduction of the carrying values of deferred tax assets by a valuation allowance is required if, based on all available evidence, it is more likely than not that such assets will not be realized. The need to establish valuation allowances for deferred tax assets is assessed at each reporting date. In assessing the requirement for, and amount of, a valuation allowance in accordance with the more-likely-than-not standard, we give appropriate consideration to all positive and negative evidence related to the realization of the deferred tax assets. This assessment considers, among other matters, the nature, frequency and severity of current and cumulative losses, forecasts of future profitability, the duration of statutory carryforward periods, our experience with operating loss and tax credit carryforwards not expiring unused and tax planning strategies. A history of cumulative losses for a certain threshold period is a significant form of negative evidence used in the assessment, and we are required to have a policy regarding the duration of the threshold period. We believe the historical cyclical nature of our operations show economic cycles ranging from 7 to 10 years with demand troughs historically showing recovery over four years . Accordingly, we have a policy of four years as our threshold period for cumulative losses. Inventory Valuation All of our inventories are stated at the lower of cost or net realizable value and are valued under the average cost method. Our inventories include materials, labor and applicable factory overhead costs. Depreciation associated with manufacturing assets is excluded from inventory cost but is included in cost of products sold. Earnings per Share Basic earnings per share is based on the weighted average number of common shares outstanding. Diluted earnings per share is based on the weighted average number of common shares outstanding plus the dilutive effect, if any, of market share units, or MSUs, restricted stock units, or RSUs, performance shares, stock options and the deferred shares associated with our deferred compensation program for non-employee directors. The shares that were not included in the computation of diluted earnings per share for those periods because their inclusion would be anti-dilutive were as follows: (millions, common shares) 2017 2016 2015 Stock options, RSUs, MSUs and performance shares 0.7 1.5 1.9 Deferred shares associated with a deferred compensation program for non-employee directors 0.2 0.2 — Business Combinations Business combinations are accounted for using the acquisition method of accounting. The purchase price of the acquisition is allocated to the tangible and intangible assets acquired and liabilities assumed based on their fair values at the acquisition date. The calculation of fair value of the identified intangible assets are determined using cash flow models following the income approach or a discounted market-based methodology approach. Significant inputs include projected revenues, gross margins, operating expenses, estimated attrition rate and discount rates. The excess of fair value of the purchase price over the fair values of the tangible and identifiable intangible assets acquired and liabilities assumed is recorded as goodwill. During the measurement period, which may be up to one year from the acquisition date, we may record adjustments to the net assets with the corresponding offset to goodwill. The results of operations of the acquired business are included in our consolidated results of operations beginning on the date of the acquisition. Acquisition-related expenses, including legal costs, due diligence costs and business valuation costs, are expensed as incurred. Cash and Cash Equivalents Cash and cash equivalents include highly liquid investments, primarily money market funds, with maturities of three months or less at the time of purchase. Marketable Securities Marketable securities are classified as available-for-sale securities and reported at fair value, with unrealized gains and losses excluded from earnings and reported in accumulated other comprehensive income (loss), or AOCI. If it is deemed that marketable securities have unrealized losses that are other than temporary, these losses will be recorded in earnings immediately. Situations in which losses may be considered other than temporary include when we have decided to sell a security or when it is more likely than not that we will be required to sell the security before we recover its amortized cost basis. Cost basis for securities sold are determined on a first-in-first-out basis. Receivables Receivables are recorded at net realizable value, which includes allowances for cash discounts and doubtful accounts. We review the collectability of receivables on an ongoing basis and reserve for receivables determined to be uncollectible. This determination is based on the delinquency of the account, the financial condition of the customer and our collection experience. We include short-term financing receivables in "Receivables" and long-term financing and loan receivables in "Other assets" on our consolidated balance sheets. Financing and loan receivables are recorded at net realizable value which includes an allowance for credit losses. We review the collectability of financing and loan receivables on an ongoing basis and reserve for financing and loan receivables determined to be uncollectible. This determination is based on the delinquency of the account and the financial condition of the other party. As of December 31, 2017 , the allowance for credit losses was immaterial. Investments in Unconsolidated Joint Ventures The equity method of accounting is used for investments in joint ventures that we do not consolidate, but over which we have the ability to exercise significant influence. These investments are initially recorded at cost and subsequently adjusted for our share of the net income or loss and cash contributions and distributions to or from these entities. If the underlying net assets in our investments are denominated in a foreign currency, we adjust the value of our investment for translation gains or losses with a corresponding adjustment to our AOCI. We are required to pay Boral, our UBBP joint venture partner, an earnout of $50 million in 2019 if certain financial metrics are met. At least quarterly, we review the probability of this earnout payment to Boral. At December 31, 2017 , we concluded that it is currently not probable that the earnout target will be achieved. If our conclusion on the probability of achievement were to change, we will record a liability representing the present value of the second earnout payment with a corresponding increase to our investment. Losses in the value of an equity method investment that are other than temporary are recognized when the current fair value of the investment is less than its carrying value. We review our investments in equity method investments for impairment whenever factors indicate an other than temporary loss in value. If we conclude a loss in value is other than temporary, an impairment charge is recognized for the difference between the investment’s carrying value and its estimated fair value. Property, Plant and Equipment Property, plant and equipment is recorded at cost. We record depreciation of property, plant and equipment on a straight-line basis over the expected useful lives of the assets. We have determined estimated useful lives to be 50 years for buildings and improvements, a range of 10 to 25 years for machinery and equipment, and a range of 5 to 7 years for computer software and systems development costs. Leasehold improvements are capitalized and amortized over the shorter of the remaining lease term or remaining economic useful life. We compute depletion on a basis calculated to spread the cost of gypsum and other applicable resources over the estimated quantities of material recoverable. We capitalize interest during the active construction period of major capital projects. Capitalized interest is added to the cost of the underlying assets and is depreciated over the useful lives of those assets. We recorded capitalized interest of $3 million , $1 million and $3 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. Facility start-up costs that cannot be capitalized are expensed as incurred and recorded in cost of products sold. Property, plant and equipment is reviewed for impairment when indicators of a potential impairment are present by comparing the carrying values of the assets with their estimated future undiscounted cash flows. If we determine an impairment exists, the asset is written down to fair value. Intangible Assets We perform impairment tests for intangible assets with indefinite useful lives once a year, or more frequently if events occur or circumstances change that would more likely than not reduce the fair value of an intangible asset below its carrying value. The impairment test for assets with indefinite lives consists of a comparison of the fair value of the asset with its carrying value. If the carrying value of an intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. Intangible assets determined to have indefinite useful lives, primarily composed of trade names, are not amortized. An income approach is used for valuing trade names. Assumptions used in the income approach include projected revenues and assumed royalty, long-term growth and discount rates. As of December 31, 2017 and 2016 , our indefinite lived intangibles, which are included in "Goodwill and intangible assets" on our consolidated balance sheets, totaled $19 million and $8 million , respectively. We perform impairment tests on definite lived intangible assets upon identification of events or circumstances that may indicate the carrying value of the assets might be unrecoverable by comparing their undiscounted cash flows with their carrying value. If we determine impairment exists, the assets are written down to estimated fair value. As of December 31, 2017 and 2016 , our definite lived intangibles, which are included in "Goodwill and intangible assets" on our consolidated balance sheets, totaled $8 million and $0 million , respectively. Goodwill We perform an impairment test on goodwill as of October 1, or more frequently if events occur or circumstances change that would more likely than not reduce the fair value below its carrying value. In testing goodwill for impairment, we have the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the estimated fair value of a reporting unit is less than its carrying value. If we elect to perform a qualitative assessment and determine that an impairment is more likely than not, we are then required to perform a quantitative impairment test, otherwise no further analysis is required. We also may elect not to perform the qualitative assessment and, instead, proceed directly to the quantitative impairment test. We perform a quantitative analysis which involves comparing the current fair value of each reporting unit to its carrying value, including goodwill. If the carrying value of a reporting unit exceeds its fair value, we recognize an impairment loss equal to the difference between the carrying value and the estimated fair value of the reporting unit. As of December 31, 2017 and 2016 , goodwill totaled $16 million and $0 million , respectively, and is included in "Goodwill and intangible assets" on our consolidated balance sheets. Asset Retirement Obligations Our asset retirement obligations include reclamation requirements as regulated by government authorities related principally to assets such as our mines, quarries, landfills, ponds and wells. The accounting for asset retirement obligations requires estimates by management about the timing of asset retirements, the cost of retirement obligations, discount and inflation rates used in determining fair values and the methods of remediation associated with our asset retirement obligations. We generally use assumptions and estimates that reflect the most likely remediation method on a site-by-site basis. Our estimated liability for asset retirement obligations is revised annually, and whenever events or changes in circumstances indicate that a revision to the estimate is necessary. In instances where a decrease in the asset retirement obligation is in excess of the related remaining net book value of the asset retirement costs, the excess is recorded to the consolidated statement of income as a reduction in "Cost of products sold." Asset retirement obligations are included in "Other liabilities" on the consolidated balance sheets. Share-Based Compensation We award share-based compensation to employees in the form of MSUs, performance shares and RSUs and to non-employee directors in the form of shares of our common stock. All grants under share-based payment programs are accounted for at fair value at the date of grant. We recognize expense on all share-based awards to employees expected to vest over the service period, which is the shorter of the period until the employees’ retirement eligibility dates or the service period of the award. We record forfeitures as they occur. Derivative Instruments We use derivative instruments to manage selected commodity price and foreign currency exposures. We do not use derivative instruments for speculative trading purposes, and we typically do not hedge beyond six years . All derivative instruments are recorded on the balance sheet at fair value. For derivatives designated as cash flow hedges, the effective portion of changes in the fair value of the derivative is recorded to AOCI, and is reclassified to earnings when the underlying forecasted transaction affects earnings. The ineffective portion of changes in the fair value of the derivative is reported in cost of products sold in the current period. For contracts designated as cash flow hedges, we reassess the probability of the underlying forecasted transactions occurring on a quarterly basis. For derivatives designated as net investment hedges, we record changes in fair value to AOCI. For derivatives not designated as hedging instruments, all changes in fair value are recorded to earnings in the current period. Cash flows from derivative instruments are included in operating activities in our consolidated statements of cash flows. We use swaps to hedge a significant portion of our anticipated purchases of natural gas to be used in our manufacturing operations. Generally, we hedge the cost of a majority of our anticipated purchases of natural gas over the next 12 months . However, we review our positions regularly and make adjustments as market conditions warrant. The majority of contracts currently in place are designated as cash flow hedges and the remainder are not designated as hedging instruments. We have operations outside of the United States and use forward contracts to hedge the risk of changes in cash flows resulting from selected forecasted intercompany and third-party sales or purchases, as well as intercompany loans, denominated in non-U.S. currencies, or to hedge the risk of selected changes in our net investment in foreign subsidiaries. These contracts are designated as either cash flow or net investment hedges or are not designated as hedging instruments. Foreign Currency Translation We translate foreign-currency-denominated assets and liabilities into U.S. Dollars at the exchange rates existing as of the respective balance sheet dates. We translate income and expense items at the average exchange rates during the respective periods. We record translation adjustments resulting from fluctuations in exchange rates to AOCI on our consolidated balance sheets. We record transaction gains and losses to earnings. We recorded a total transaction loss of $4 million in 2017 , a gain of $3 million in 2016 and a loss of $7 million in 2015 . Transaction gains and losses are included in "Other (expense) income, net" in our consolidated statements of income. Fair Value Measurements Certain assets and liabilities are required to be recorded at fair value. The estimated fair values of those assets and liabilities have been determined using market information and valuation methodologies. Changes in assumptions or estimation methods could affect the fair value estimates. However, we do not believe any such changes would have a material impact on our financial condition, results of operations or cash flows. There are three levels of inputs that may be used to measure fair value: • Level 1 – Quoted prices for identical assets and liabilities in active markets; • Level 2 – Quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets; and • Level 3 – Valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. Certain assets and liabilities are measured at fair value on a nonrecurring basis rather than on an ongoing basis, but are subject to fair value adjustments in certain circumstances, such as an acquisition, when evidence of impairment or when a new liability is being established that requires fair value measurement.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Accounting Pronouncements We adopted Accounting Standards Update, or ASU 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment," on November 30, 2017 in connection with our acquisition of Ceilings Plus, which eliminates Step 2 from the goodwill impairment test. Under the new standard, an impairment charge would be recognized for the amount by which the carrying value exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The adoption did not have an impact on our consolidated financial statements. We adopted ASU 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting,” on January 1, 2017. This ASU simplifies certain aspects of accounting for employee share-based payments. Upon adoption, we recorded to retained earnings a $25 million cumulative-effect adjustment for previously unrecognized excess tax benefits and an immaterial cumulative-effect adjustment for the reversal of cumulative forfeiture estimates to record forfeitures as they occur. Recently Issued Accounting Pronouncements In August 2017, the Financial Accounting Standards Board, or FASB, issued ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities,” which expands and refines hedge accounting for both non-financial and financial risk components and aligns the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. The new standard will be effective for us on January 1, 2019. We do not expect the adoption of ASU 2017-12 to have a significant impact to our consolidated financial statements or disclosures. In March 2017, the FASB issued ASU 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” which will require us to disaggregate and present current service cost along with other current compensation costs for employees while presenting other net benefit cost components below operating profit. In addition, only the service cost component of net benefit cost is eligible for capitalization in our inventory and fixed assets. We will retrospectively adopt the standard on January 1, 2018 for the presentation of service cost using the practical expedient and prospectively adopt the capitalization of only service cost into inventory and fixed assets. Select line items from our consolidated statements of income for the years ended December 31, 2017 and 2016 which reflect the changes in presentation of net benefit costs are as follows: (millions) Year ended December 31, 2017 Year ended December 31, 2016 After Adoption As Reported After Adoption As Reported Gross profit $ 656 $ 665 $ 700 $ 705 Operating profit 353 367 396 394 Other net periodic postretirement benefit (costs) 14 — (2 ) — Net income 88 88 510 510 We do not expect the adoption of ASU 2017-07 to have a significant impact on our other financial statements. In January 2017, the FASB issued ASU 2017-01, "Business Combinations (Topic 805): Clarifying the Definition of a Business," which clarifies the definition of a business in order to assist in the evaluation of whether transactions should be accounted for as acquisitions or disposals of assets or businesses. We will prospectively adopt the standard on January 1, 2018. The impact of our adoption of ASU 2017-01 will be dependent on the nature of future acquisitions or dispositions, if any. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash,” which requires amounts generally described as restricted cash and restricted cash equivalents to be included with cash and cash equivalents when reconciling beginning-of-period and end-of-period total amounts shown on the statement of cash flows. We will adopt the standard on January 1, 2018 using the retrospective approach. The adoption will result in a $9 million reduction of our net cash provided by investing activities on our consolidated statement of cash flows for the year ended December 31, 2016. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842),” which supersedes existing lease guidance to require lessees to recognize assets and liabilities on the balance sheet for the rights and obligations created by long-term leases and to disclose additional quantitative and qualitative information about leasing arrangements. We will adopt the new standard on January 1, 2019 using the modified retrospective approach. As a result of the new standard, we will implement a new lease accounting system, new processes and accounting policies. Further, we anticipate the adoption of ASU 2016-02 will have a significant impact to our consolidated balance sheets and disclosures. We are currently finalizing our accounting policies and analyzing our lease population and, thus, we are unable to quantify the financial statement impact at this time. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition requirements in “Revenue Recognition (Topic 605),” and requires entities to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Subsequently, the FASB has issued various ASUs to provide further clarification around certain aspects of Topic 606. We will adopt, via the modified retrospective approach, the standard on January 1, 2018 using practical expedients. With our adoption of the new revenue guidance, we will modify the point in time at which we record revenue to be upon shipment for most of our customers and will record an adjustment to opening retained earnings of $2 million . The adoption will not have a significant impact to our consolidated financial statements. However, we will expand our disclosures to include disaggregation of revenue and discussion on the satisfaction of our performance obligations.

Acquisition and Disposition

Acquisition and Disposition	12 Months Ended
	Dec. 31, 2017
Business Combinations And Discontinued Operations and Disposal Groups [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions Acquisition of Ceilings Plus On November 30, 2017, we completed our acquisition of Ceilings Plus for $52 million with an expected working capital adjustment to be measured and recorded in 2018. The addition of Ceilings Plus to our U.S. Ceilings segment expands our operations in the specialty ceilings markets. The preliminary fair value of tangible assets acquired, less liabilities assumed, in connection with the Ceilings Plus acquisition was $16 million . The preliminary fair value of intangible assets acquired, which included customer relationships and trade names, totaled $20 million . The resulting preliminary goodwill recorded was $16 million and all is expected to be deductible for tax purposes. The goodwill resulting from this acquisition consists largely of the company’s expected future product sales and synergies with the existing U.S. Ceilings product offerings. No impairments were recorded in 2017. The acquisition is immaterial to our consolidated statement of income for the year end December 31, 2017. Discontinued Operations On October 31, 2016, we completed the sale of our L&W distribution business to ABC Supply for total cash consideration of $675 million inclusive of the final working capital adjustment and recorded a gain on the sale of $279 million . For the year ended December 31, 2016, L&W met the criteria to be classified as held for sale and to be presented as a discontinued operation. Accordingly, we reclassified the results of operations and the cash flows of L&W to discontinued operations in our consolidated statements of income and consolidated statements of cash flows for all periods presented. The summarized financial information related to L&W that has been excluded from continuing operations and reported as a discontinued operation is as follows: (millions) For the year ended December 31, 2016(a) 2015 Net sales $ 1,252 $ 1,428 Cost of products sold 1,196 1,387 Gross profit 56 41 Selling and administrative expenses (b) 22 15 Operating profit 34 26 Income tax expense 12 11 Net income from discontinued operations (c) $ 22 $ 15 Gain on sale of discontinued operations $ 279 $ — (a) Operating results for 2016 are presented for the ten months ended October 31, 2016. (b) The ten month period ended October 31, 2016 included transaction costs of $8 million . (c) The year ended December 31, 2016 included $2 million of net loss from discontinued operations from our European business, which were sold in 2012. For the twelve months ended December 31, 2017, we recorded a net loss of $9 million to "(Loss) income from discontinued operations," which reflected a $8 million loss for L&W primarily due to a pension settlement and a loss of $1 million for our European operations which were sold in December 2012. Additionally, upon the close of the sale, we entered into a supply agreement with L&W. For the year ended December 31, 2017, we recorded sales of $510 million and cash inflows related to payments on trade receivables of $489 million . For the years ended December 31, 2016 and 2015, the sales that were sold by L&W to third party customers were $568 million and $531 million , respectively. For the two months in 2016 after the sale of L&W, we recorded a cash inflow of $102 million related to payments on trade receivables.

Equity Method Investments

Equity Method Investments	12 Months Ended
	Dec. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	Equity Method Investments Equity method investments were as follows: December 31, 2017 December 31, 2016 (millions) Carrying Value Ownership Percentage Carrying Value Ownership Percentage USG Boral Building Products $ 679 50% $ 621 50% Other equity method investments 7 33% - 50% $ 7 33% - 50% Total equity method investments $ 686 $ 628 Investments in USG Boral Building Products (UBBP) During 2017 , UBBP paid cash dividends on earnings through September 2017 of which our 50% share totaled $42 million . As of December 31, 2017 , the amount of our consolidated retained earnings which represents undistributed earnings from UBBP is $60 million . In the event certain U.S. Dollar denominated performance targets are satisfied by UBBP, we are obligated to pay Boral an earnout payment of up to $50 million based on performance through 2019. We have not recorded a liability for this earnout payment as we have concluded that it is currently not probable that the five years performance target will be achieved. In the second quarter of 2016, we reversed a liability with a corresponding reduction to our investment for an earn-out payment that was based on a three years performance target. Translation gains and losses recorded in other comprehensive income were as follows: (millions) 2017 2016 2015 Translation gain (loss) $ 40 $ (30 ) $ (23 ) Transactions with UBBP Our U.S. Wallboard and Surfaces and U.S. Performance Materials segments sell products to UBBP. Total sales to UBBP for each of the years ended December 31, 2017 , 2016 and 2015 were immaterial. In 2014, in connection with the formation of UBBP, we contributed our ownership interest in a joint venture in China to UBBP but retained our loan receivable from this joint venture. As of December 31, 2017 and 2016 , the loan receivable, including interest, totaled $13 million and $15 million , respectively, and is included in "Other assets" on our consolidated balance sheets. Investment in Knauf-USG Joint Venture In 2015, we sold our 50% interest in Knauf/USG Verwaltungs GmbH and Knauf/USG Systems GmbH & Co. KG, or collectively the Knauf-USG joint venture, to our joint venture partner, Knauf Aquapanel GmbH, a subsidiary of Gebr. Knauf Verwaltungsgesellschaft KG (Knauf) for €48 million in cash, or approximately $52 million . The Knauf-USG joint venture manufactured and distributed Aquapanel ® brand cement-based panels in Europe (excluding Turkey) and all countries that were part of the former Soviet Union. Affiliates of Knauf are the beneficial owners of approximately 10% of USG's outstanding shares of common stock. We recorded a gain of approximately $6 million , which is net of $5 million for income taxes payable on the sale. The gross gain and our equity method income in the Knauf-USG joint venture was $13 million for the year ended December 31, 2015 and is recorded in "Income and gain from the sale of equity method investment to related party" in our consolidated statement of income. Summarized Financial Information Summarized financial information for our equity method investments is as follows: Statements of Income For the year ended December 31, (millions) 2017 2016 2015 USG Boral Building Products: Net sales $ 1,200 $ 1,052 $ 1,003 Gross profit (a) 369 337 278 Operating profit 160 133 124 Net income before taxes 174 142 132 Net income 121 95 101 Net income attributable to USG Boral Building Products 117 99 96 USG share of income from USG Boral Building Products (b) 59 49 48 Other equity method investments (c) : USG share of income from other investments accounted for using the equity method — — 2 Total income from equity method investments 59 49 50 (a) Year ended December 31, 2016 includes long-lived asset impairment charges of $8 million for China and of $14 million for Oman. (b) Year ended December 31, 2016 includes long-lived asset impairment charges of $4 million for China and of $4 million for Oman. (c) Amounts represent our share of income or loss from all equity method investments, other than UBBP. Balance Sheets (millions) December 31, 2017 December 31, 2016 USG Boral Building Products: Current assets $ 438 $ 389 Non-current assets 981 903 Current liabilities (a) 255 211 Long-term debt 10 37 Other non-current liabilities 12 17 Shareholders' equity (b) 1,142 1,027 (a) Includes the current portion of long-term debt of $16 million and $15 million as of December 31, 2017 and 2016 , respectively. (b) Shareholders' equity includes $66 million and $50 million related to non-controlling interests as of December 31, 2017 and 2016 , respectivel y.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Marketable Securities Our investments in marketable securities as of December 31, 2017 and 2016 consisted of the following: 2017 2016 (millions) Amortized Cost Fair Value Amortized Cost Fair Value Corporate debt securities $ 68 $ 68 $ 69 $ 69 U.S. government and agency debt securities 6 6 14 14 Asset-backed debt securities 11 11 2 2 Certificates of deposit 13 13 6 6 Municipal debt securities 1 1 — — Total marketable securities $ 99 $ 99 $ 91 $ 91 The realized and unrealized gains and losses as of and for the years ended December 31, 2017 , 2016 and 2015 were immaterial. Contractual maturities of marketable securities as of December 31, 2017 were as follows: (millions) Amortized Cost Fair Value Due in 1 year or less $ 62 $ 62 Due in 1-5 years 37 37 Total marketable securities $ 99 $ 99 Actual maturities may differ from the contractual maturities because issuers of the securities may have the right to prepay them.

Debt

Debt	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Debt	Debt Total debt as of December 31 consisted of the following: (millions) 2017 2016 4.875% senior notes due 2027 $ 500 $ — 5.5% senior notes due 2025 350 350 7.75% senior notes due 2018 — 500 Industrial revenue bonds (due 2028 through 2034) 239 239 Total $ 1,089 $ 1,089 Less: Unamortized debt issuance costs 11 6 Total $ 1,078 $ 1,083 Issuance of Senior Notes During 2017, we issued $500 million of 4.875% senior notes due 2027, referred to as our 4.875% Notes. The net proceeds from the issuance of these notes and cash on hand were used to fund the repurchase of our 7.75% senior notes due 2018, referred to as our 7.75% Notes, and all related costs and expenses. We deferred $7 million of debt issuance costs that are being amortized to interest expense over the term of the 4.875% Notes. In 2015, we issued $350 million of 5.5% senior notes due 2025, referred to as our 5.5% Notes. The net proceeds from the issuance of these notes and cash on hand were used to fund the repurchase of our 8.375% senior notes due 2018, referred to as our 8.375% Notes, and all related costs and expenses. We deferred approximately $6 million of debt issuance costs that are being amortized to interest expense over the term of the notes. Repurchases and Redemptions of Senior Notes During 2017, we repurchased $500 million of our 7.75% Notes through a cash tender offer and subsequent redemption for aggregate consideration of $536 million , including premiums of $20 million and accrued interest of $16 million . For the year ended December 31, 2017, we recorded a pre-tax loss on the early extinguishment of debt of $21 million . During 2016, we repaid $500 million of our 6.3% senior notes due 2016, referred to as the 6.3% Notes, $250 million of our 7.875% senior notes due 2020, referred to as the 7.875% Notes, and $350 million of our 5.875% senior notes due 2021, referred to as the 5.875% Notes. The retirement of the 6.3% Notes, the 7.875% Notes and the 5.875% Notes included premiums of $30 million and accrued interest of $9 million . As a result of these transactions, we recorded a loss on the early extinguishment of debt, before tax, of $37 million including premiums, write-off of deferred financing fees, debt discount and broker fees. During 2015, we repurchased $350 million of our 8.375% Notes, through a cash tender offer and subsequent redemption for aggregate consideration, including tender offer premium and accrued and unpaid interest, of $377 million . As a result of the repurchases, we recorded a loss on the early extinguishment of debt of $19 million including the write-off of unamortized debt issuance costs. Senior Notes Our senior notes are senior unsecured obligations, rank equally with all of our other existing and future unsecured senior indebtedness and are guaranteed by certain of our domestic subsidiaries. The indentures governing the notes contain events of default, covenants and restrictions that are customary for similar securities, including a limitation on our ability and the ability of certain of our subsidiaries to create or incur secured indebtedness. Interest rate 5.5% 4.875% Principal net of discount (in millions) (a) $350 $500 Maturity March 1, 2025 June 1, 2027 Call date (b) March 1, 2020 June 1, 2022 Mandatory redemption offer at 101% plus accrued and unpaid interest in the event of a change in control at 101% plus accrued and unpaid interest in the event of a change in control (a) Principal amounts exclude unamortized debt issuance costs. (b) Callable at any time, in whole or in part, prior to the call date at a redemption price equal to 100% of the principal plus a premium (as outlined in the respective indentures), plus any accrued and unpaid interest on the principal amount being called. Callable after the call date at stated redemption prices (as outlined in the applicable indenture), plus any accrued and unpaid interest on the principal amount being called. Credit Facility In 2017, we amended and restated our credit facility agreement to, among other things, increase the maximum borrowing limit from $180 million to $220 million . As a result, we recorded a pre-tax loss on extinguishment of debt of $1 million for the year ended December 31, 2017 and incurred $1 million of debt issuance costs. Our amended and restated agreement requires us to maintain a minimum fixed charge coverage ratio in the event excess availability falls below a minimum threshold. Because our excess borrowing availability as of December 31, 2017 of $155 million exceeds this threshold, the requirement to maintain the minimum fixed charge coverage ratio is not applicable. As of December 31, 2017 , we were in compliance with the covenants contained in our credit facility. As of December 31, 2017 and during the year then ended, there were no borrowings under the facility. Outstanding letters of credit as of December 31, 2017 totaled $29 million . Industrial Revenue Bonds Our $239 million of industrial revenue bonds have fixed interest rates ranging from 5.5% to 6.4% . The weighted average rate of interest on our industrial revenue bonds is 5.875% . These bonds mature during the years 2028 through 2034 . OTHER INFORMATION (millions) December 31, 2017 December 31, 2016 Fair value of debt $ 1,134 $ 1,129 Accrued interest 12 31 The fair value of our debt was determined using the fair value hierarchy of inputs described in Note 1. The fair values were determined utilizing prices from independent pricing services. The vendors’ methodologies utilize various forms of market data, including but not limited to, trade data, yield, spreads, bids and offers. We review the values provided by the independent pricing service for reasonableness by comparing the valuations received from the independent pricing service to valuations from at least one other observable source. We have not adjusted the prices obtained from the independent pricing service. As a result, the fair values are classified as Level 2. See Note 8 for further discussion on fair value measurements. As of December 31, 2017 , the amounts of total debt outstanding maturing in each of the next five years and beyond were as follows: (millions) 2018 through 2022 After 2022 Debt maturities (principal amounts) $ — $ 1,089

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments We use derivative instruments to manage selected commodity price and foreign currency exposures as described below. Derivative Instruments Type Hedged Item Aggregate Notional Amount Contracts Maturing Through Commodity Natural gas swaps Purchases of natural gas 38 million mmBTUs* December 31, 2022 Foreign Exchange Forward contracts Purchases of products and services denominated in a foreign currency $95 million December 31, 2018 * - millions of British Thermal Units During 2015, we entered into foreign exchange forward contracts with a notional amount of $35 million to hedge a portion of our net investment in our Knauf-USG joint venture. These forward contracts were designated as net investment hedges and no ineffectiveness was recorded. On December 22, 2015, we completed the sale of our Knauf-USG joint venture and, as a result, we terminated the outstanding foreign exchange forward contracts and reclassified a $1 million net gain realized for these contracts from AOCI to earnings which increased the gain on the sale of the equity method investment. See Note 4 for further discussion on the sale. COUNTERPARTY RISK, MASTER NETTING ARRANGEMENTS AND BALANCE SHEET OFFSETTING We are exposed to credit losses in the event of nonperformance by the counterparties to our derivative instruments. As of December 31, 2017 , our derivatives were in a $15 million net liability position. All of our counterparties have investment grade credit ratings; accordingly, we anticipate that they will be able to fully satisfy their obligations under the contracts. All of our derivative contracts are governed by master netting agreements negotiated between us and the counterparties that reduce our counterparty credit exposure. The agreements outline the conditions (such as credit ratings and net derivative fair values) upon which we, or the counterparties, are required to post collateral. As required by certain of our agreements, we had $13 million of collateral posted with our counterparties related to our derivatives as of December 31, 2017 . Amounts paid as cash collateral are included in "Receivables" on our consolidated balance sheets. We have not adopted an accounting policy to offset fair value amounts related to derivative contracts under our master netting arrangements; therefore, individual derivative contracts are reflected on a gross basis, as either assets or liabilities, on our consolidated balance sheets, based on their fair value as of the balance sheet date. FINANCIAL STATEMENT INFORMATION The following are the pre-tax effects of derivative instruments on our consolidated statements of income and our consolidated statements of comprehensive income for the years ended December 31, 2017 , 2016 and 2015 : Amount of Gain or (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives (Effective Portion) Location of Gain or (Loss) Reclassified from AOCI into Income (Effective Portion) Amount of Gain or (Loss) Reclassified from AOCI into Income (Effective Portion) (millions) 2017 2016 2015 2017 2016 2015 Derivatives Designated as Hedging Instruments Commodity contracts $ (19 ) $ 6 $ (14 ) Cost of products sold $ (4 ) $ (15 ) $ (15 ) Foreign exchange contracts (5 ) (3 ) 12 Cost of products sold (2 ) 5 7 Foreign exchange contracts — — 1 Income and gain from the sale of equity method investment to related party — — 1 Total $ (24 ) $ 3 $ (1 ) $ (6 ) $ (10 ) $ (7 ) Location of Gain or (Loss) Recognized in Income on Derivatives Amount of Gain or (Loss) Recognized in Income on Derivatives (millions) 2017 2016 2015 Derivatives Not Designated as Hedging Instruments Commodity contracts Cost of products sold $ (1 ) $ 1 $ (3 ) Foreign exchange contracts Other (income) expense, net — — 2 Total $ (1 ) $ 1 $ (1 ) For both commodity contracts and foreign exchange contracts, no ineffectiveness was recorded in 2017 , 2016 or 2015 . The fair values of derivative instruments on the consolidated balance sheets are as follows: Balance Sheet Location Fair Value Balance Sheet Location Fair Value (millions) 12/31/17 12/31/16 12/31/17 12/31/16 Derivatives Designated as Hedging Instruments Commodity contracts Other current assets $ 1 $ 8 Accrued expenses $ 6 $ 4 Commodity contracts Other assets 1 3 Other liabilities 8 5 Foreign exchange contracts Other current assets — 1 Accrued expenses 3 1 Total derivatives in hedging relationships $ 2 $ 12 $ 17 $ 10 Derivatives Not Designated as Hedging Instruments Commodity contracts Other current assets $ — $ 1 Accrued expenses $ — $ — Commodity contracts Other assets — — Other liabilities — — Total derivatives not designated as hedging instruments $ — $ 1 $ — $ — Total derivatives Total assets $ 2 $ 13 Total liabilities $ 17 $ 10 As of December 31, 2017 , we had no derivatives designated as net investment or fair value hedges.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities are required to be recorded at fair value. The fair values of our cash equivalents, equity mutual funds, marketable securities and derivatives were determined using the fair value hierarchy of inputs described in Note 1 . Level USG Valuation Method Level 1 Cash equivalents and equity mutual funds consist of money market funds that are valued based on quoted prices in active markets. Level 2 Marketable securities, including certain cash equivalents, are valued using a "market value" approach. Values are based on quoted prices and other observable market inputs received from data providers. Derivatives are valued using the "income" approach such as discounted-cash-flow models and readily observable market data. The inputs for the valuation models are obtained from data providers and include end-of-period spot and forward natural gas prices, foreign currency exchange rates, natural gas price volatility and LIBOR and swap rates for discounting the cash flows implied from the derivative contracts. Level 3 No level 3 investments. Our assets and liabilities measured at fair value on a recurring basis were as follows: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (millions) 12/31/17 12/31/16 12/31/17 12/31/16 12/31/17 12/31/16 12/31/17 12/31/16 Cash equivalents $ 124 $ 38 $ 24 $ 34 $ — $ — $ 148 $ 72 Equity mutual funds 6 5 — — — — 6 5 Marketable securities: Corporate debt securities — — 68 69 — — 68 69 U.S. government and agency debt securities — — 6 14 — — 6 14 Asset-backed debt securities — — 11 2 — — 11 2 Certificates of deposit — — 13 6 — — 13 6 Municipal debt securities — — 1 — — — 1 — Derivative assets — — 2 13 — — 2 13 Derivative liabilities — — (17 ) (10 ) — — (17 ) (10 )

Employee Retirement Plans

Employee Retirement Plans	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Employee Retirement Plans	Employee Retirement Plans We maintain defined benefit pension plans for most of our employees. Most of these plans require employee contributions in order to accrue benefits. Benefits payable under the plans are based on employees’ years of service and compensation during specified years of employment. Effective December 31, 2010, we amended the USG Corporation defined benefit pension plan to replace the final average pay formula with a cash balance formula for employees hired after that date. In November 2016, we amended the U.S. pension plan to allow retirees and all terminated vested employees to take a lump-sum at all times without restriction. We also maintain plans that provide postretirement benefits (retiree health care and life insurance) for eligible employees. Employees hired before January 1, 2002 generally become eligible for the postretirement benefit plans when they meet minimum retirement age and service requirements. The cost of providing most postretirement benefits is shared with retirees. Upon the sale of L&W, we retained responsibility for the benefits payable to employees of L&W for the benefits accrued while employed by USG under the USG pension and postretirement plans. All L&W employees had the option to receive a lump sum benefit payment from the USG Corporation pension plan upon termination of their employment from USG. The total of the lump sum distributions made by the USG Corporation pension plan to both L&W employees and USG retirees or terminated vested employees during both 2017 and 2016 exceeded the settlement threshold and, as a result, we incurred settlement expense of $25 million and $26 million , respectively. The benefits payable to employees of L&W who did not take lump sum distributions in connection with their termination or retirement from USG are included in our benefit obligation as of December 31, 2017. The location of the settlement expense within our consolidated statements of income and the group of employees for which it is related is as follows: (millions) 2017 2016 Cost of products sold USG retirees or terminated vested employees $ 10 $ 7 Selling and administrative expenses USG retirees or terminated vested employees 2 4 (Loss) income from discontinued operations Terminated employees of L&W 13 — Gain on sale of discontinued operations Terminated employees of L&W — 15 Total $ 25 $ 26 Additionally, as a result of the sale of L&W, we recorded a curtailment gain of $20 million for the year ended December 31, 2016 for our postretirement plan to "Gain on sale of discontinued operations" in our consolidated statement of income, for those benefits no longer accruable to the employees of L&W who were not retirement eligible or did not elect retirement upon employment termination from USG. In 2011 and 2014, we amended our U.S. postretirement benefit plan to require retiree medical plan participants to begin purchasing individual coverage in the Affordable Insurance Exchanges or individual Medicare marketplace beginning January 1, 2016 using a company-funded subsidy. The subsidy is determined based upon years of service at retirement and Medicare eligibility. As a result of the amendments, the measurement of the accumulated postretirement benefit obligation, or APBO, was reduced and a credit to unrecognized prior service cost is being amortized into the statement of income over the average remaining service of active plan participants to retirement eligibility. This is reflected in net amortization of postretirement benefits in the table below. The subsidy provided to retirees eligible for Medicare will end December 31, 2019 at which time there will be no remaining credit to be amortized to the income statement for the unrecognized prior service cost. The components of net pension and postretirement benefit costs are summarized in the following table: (millions) 2017 2016 2015 Pension Benefits: Service cost of benefits earned $ 44 $ 45 $ 49 Interest cost on projected benefit obligation 61 66 66 Expected return on plan assets (93 ) (89 ) (83 ) Settlement (a) 25 35 1 Net amortization 22 22 39 Net pension cost (b) $ 59 $ 79 $ 72 Postretirement Benefits: Service cost of benefits earned $ 2 $ 2 $ 2 Interest cost on projected benefit obligation 5 6 6 Curtailment — (20 ) — Net amortization (23 ) (27 ) (31 ) Net postretirement benefit (c) $ (16 ) $ (39 ) $ (23 ) (a) In 2016, $26 million of the settlement charge reflects the increase in lump sum benefits paid largely driven by the sale of L&W and $9 million reflected payments from our supplemental plan. (b) Net pension costs, excluding settlement costs, includes amounts allocated to (loss) income from discontinued operations for L&W totaling a benefit of $1 million for 2017 and expense of $7 million for 2016 and $12 million for 2015. (c) Net postretirement benefit, excluding curtailment gain, includes a net benefit allocated to (loss) income from discontinued operations for L&W of $1 million for 2017, $3 million for 2016 and $3 million for 2015. We use a December 31 measurement date for our plans. The accumulated benefit obligation, or ABO, for the defined benefit pension plans was $ 1.506 billion as of December 31, 2017 and $ 1.396 billion as of December 31, 2016 . As of December 31, (millions) 2017 2016 Selected information for pension plans with accumulated benefit obligations in excess of plan assets: Accumulated benefit obligation $ (35 ) $ (39 ) Fair value of plan assets 3 2 Selected information for pension plans with benefit obligations in excess of plan assets: Benefit obligation $ (1,769 ) $ (1,384 ) Fair value of plan assets 1,576 1,205 The following table summarizes projected benefit obligations, plan assets and funded status as of December 31: Pension Postretirement (millions) 2017 2016 2017 2016 Change in Benefit Obligation: Benefit obligation as of January 1 $ 1,610 $ 1,564 $ 135 $ 144 Service cost 44 45 2 2 Interest cost 61 66 5 6 Settlements (121 ) (123 ) — — Curtailments — (37 ) — (7 ) Participant contributions 9 11 — — Benefits paid (51 ) (33 ) (6 ) (7 ) Actuarial (gain) loss 202 112 10 (5 ) Foreign currency translation 16 5 4 2 Benefit obligation as of December 31 $ 1,770 $ 1,610 $ 150 $ 135 Change in Plan Assets: Fair value as of January 1 $ 1,435 $ 1,301 $ — $ — Actual return on plan assets 217 107 — — Employer contributions 71 167 6 7 Participant contributions 9 11 — — Benefits paid (51 ) (33 ) (6 ) (7 ) Settlements (121 ) (123 ) — — Foreign currency translation 17 5 — — Fair value as of December 31 $ 1,577 $ 1,435 $ — $ — Funded status $ (193 ) $ (175 ) $ (150 ) $ (135 ) Components on the Consolidated Balance Sheets: Noncurrent assets $ — $ 4 $ — $ — Current liabilities (8 ) (16 ) (9 ) (8 ) Noncurrent liabilities (185 ) (163 ) (141 ) (127 ) Net liability as of December 31 $ (193 ) $ (175 ) $ (150 ) $ (135 ) Pretax Components in AOCI: Net actuarial loss $ 421 $ 388 $ 11 $ — Prior service credit — (1 ) (42 ) (65 ) Total as of December 31 $ 421 $ 387 $ (31 ) $ (65 ) For our defined benefit pension plans, the 2017 actuarial loss of $202 million was primarily due to a decrease in the discount rates partially offset by the adoption of the new mortality tables used to determine the benefit obligation. For the defined benefit pension plans, we estimate that during 2018 we will amortize from AOCI into net pension cost a net actuarial loss of $ 31 million and no prior service cost . For the postretirement benefit plans, we estimate that during 2018 we will amortize from AOCI into net postretirement cost a net actuarial loss of $ 1 million and a prior service credit of $ 23 million . ASSUMPTIONS The following tables reflect the assumptions used in the accounting for our plans: Pension Postretirement 2017 2016 2017 2016 Weighted average assumptions used to determine benefit obligations as of December 31: Discount rate 3.55 % 4.02 % 3.42 % 3.90 % Compensation increase rate 3.54 % 3.55 % N/A N/A Weighted average assumptions used to determine net cost for years ended December 31: Discount rate 4.02 % 4.43 % 3.90 % 4.24 % Expected return on plan assets 6.54 % 6.66 % N/A N/A Compensation increase rate 3.55 % 3.55 % N/A N/A We no longer have significant exposure to health care cost trend rates due to the modifications we made to our U.S. postretirement health care plan to limit the increase in the annual amount we pay for retiree health care coverage for certain current and future retirees to 3% and to require retiree medical plan participants to begin purchasing individual coverage in the Affordable Insurance Exchanges or individual Medicare marketplace beginning January 1, 2016 using a company-funded subsidy based upon years of service at retirement. For the measurement of the APBO at December 31, 2017 for our Canadian postretirement health care plan, the assumed health care cost trend rates start with a 5.95% increase in 2018 , followed by a gradual decline in increases to 4% for 2046. For the measurement of the APBO at December 31, 2016 , the assumed health care cost trend rates started with a 7.75% increase in 2017 , followed by a gradual decline in increases to 4% for 2032 and beyond. A one percentage point change in the assumed health care cost trend rates would have the following effects on our Canadian plans: (millions) One-Percentage- Point Increase One-Percentage- Point Decrease Effect on total service and interest cost $ 1 $ — Effect on postretirement benefit obligation 13 (10 ) RETIREMENT PLAN ASSETS Investment Policies and Strategies : We have established investment policies and strategies for the defined benefit pension plans’ assets with a long-term objective of maintaining the plans’ assets at a level equal to or greater than that of their liabilities (as measured by a funded ratio of 100% or more of the ABO) and maximizing returns on the plans’ assets consistent with our moderate tolerance for risk. Contributions are made to the plans periodically as needed to meet funding targets or requirements. Factors influencing our determination to accept a moderate degree of risk include the timing of plan participants’ retirements and the resulting disbursement of retirement benefits, the liquidity requirements of the plans and our financial condition. Our overall long-term objective is to achieve a 6.5% rate of return on plan assets with a moderate level of risk as indicated by the volatility of investment returns. This rate of return target was established using a “building block” approach. In this approach, ranges of long-term expected returns for the various asset classes in which the plans invest are estimated. The estimated ranges are primarily based on observations of historical asset returns and their historical volatility. In determining the expected returns, we also consider consensus forecasts of certain market and economic factors that influence returns, such as inflation, gross domestic product trends and dividend yields. We then calculate an overall range of likely expected rates of return by applying the expected asset returns to the plans’ target asset allocation. The most likely rate of return is then determined and is adjusted to account for investment management fees. Our investment strategy is to invest in a diversified mix of asset classes in accordance with an asset allocation that we believe is likely to achieve our long-term target return while prudently considering risk. In order to manage risk, the plans’ pension and investment committees periodically rebalance the asset allocations as outlined by our investment policy statements. Our investment policy statements include glide paths which outline how our asset allocation would increase the portion of liability-hedging assets, such as fixed income, as our funded status improves in the future. This liability-driven investing approach is carried out by professional investment managers who help the committees in this process. The committees also monitor the investment performance of the individual investment managers compared to their benchmark returns and investment guidelines on an ongoing basis, in part through the use of quarterly investment portfolio reviews and compliance reporting by investment managers. The pension and investment committees also evaluate risk by periodically conducting asset/liability studies to assess the correlation of the plans’ assets and liabilities and the degree of risk in the target asset allocations. The plans limit the use of leverage to select investment strategies where leverage is typically employed, such as private equity and real estate. Certain investment managers utilize derivatives, such as swaps, bond futures, and options, as part of their investment strategies. This is done primarily to gain a desired market exposure or manage factors such as interest rate risk or duration of a bond portfolio. The following table shows the aggregate target asset allocation on a weighted average basis for all the plans and the acceptable ranges around the targets as of December 31, 2017 . Investment Policy Asset Categories Asset Category Description Target Range Equity Institutional commingled/pooled equity funds, equity mutual funds and direct holdings of the common stock of U.S. and non-U.S. companies; equity funds and direct holdings are invested in companies with a range of market capitalizations 36% 32%-40% Fixed income U.S. Treasury securities, non-U.S. government debt securities such as Canadian federal bonds, corporate bonds of companies from diversified industries and mortgage-backed securities 54% 45%-63% Limited partnerships Investments in funds that follow any of several different strategies, including investing in distressed debt, energy development, infrastructure, and hedge funds. These investments use strategies with returns normally expected to have a reduced correlation to the return of equities as compared to other asset classes and often provide a current income component that is a meaningful portion of the investment’s total return. 5% 1%-8% Other real assets Primarily investments in large core, private real estate funds that directly own a diverse portfolio of properties located in the United States. It also includes an allocation to funds investing in equities of real estate and infrastructure companies 5% 2%-9% Cash equivalents and short-term investments Primarily held in short-term investment funds or registered money market funds with daily liquidity —% 0%-5% Total 100% Fair Values of Plan Assets : Pension assets are classified based on the valuation methodologies and inputs used to determine the fair value as described in Note 1. Level 1 investments include direct investments in common stocks of U.S. and non-U.S. companies that trade on liquid exchanges. These investments are valued based on the closing price on these exchanges. Level 2 investments include primarily fixed income securities such as corporate, or government debentures, mortgage- and asset-backed securities. They are valued primarily using income and market approaches, such as pricing based on recent market transactions, and values are based on quoted prices or other observable market inputs received from data providers. Commingled funds not traded on an exchange, even though their underlying investments are common stocks traded on liquid exchanges, are also included in the Level 2 category. The net asset value of commingled funds investing in either stocks or fixed income securities is calculated by subtracting the value of any liabilities from the market value of all securities owned by a fund. Level 3 investments include real estate, infrastructure, or direct energy investments as well as distressed securities or hedge funds. These are valued using income approach methodologies such as discounted cash flows, or market approach methodologies such as relative value (specific to equity securities), direct capitalization and comparable sales (specific to real estate investments). Some of the key inputs used to value these securities include discount rate, EBITDA multiple, yield-to-worst, yield-to-maturity, and cap rate (specific to real estate investments). The fair values by hierarchy of inputs as of December 31 were as follows: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (millions) 2017 2016 2017 2016 2017 2016 2017 2016 Asset Categories: Equity: Common and preferred stock $ 92 $ 66 $ — $ — $ — $ — $ 92 $ 66 Commingled/pooled/mutual funds (a) — — 553 490 — — 553 490 Total equity 92 66 553 490 — — 645 556 Fixed income: U.S. government and agency debt securities — — 8 194 — — 8 194 Non-U.S. government and agency debt securities — — 68 54 — — 68 54 Investment-grade debt securities — — 334 197 — — 334 197 High-yield debt securities — — 42 53 — — 42 53 Commingled/pooled funds (a) — — 305 165 — — 305 165 Mortgaged backed securities — — 1 3 — — 1 3 Other — — 13 10 1 1 14 11 Total fixed income — — 771 676 1 1 772 677 Limited partnerships — — — — 91 103 91 103 Other real estate assets — — 18 16 39 38 57 54 Cash equivalents and short-term investments — — 14 11 — — 14 11 Total $ 92 $ 66 $ 1,356 $ 1,193 $ 131 $ 142 $ 1,579 $ 1,401 Cash on hand — — Receivables 2 35 Accounts payable (4 ) (1 ) Total $ 1,577 $ 1,435 (a) Certain investments in commingled/pooled equity funds have been classified as Level 2 because observable quoted prices for these institutional funds are not available. A reconciliation of the change in the fair value measurement of the defined benefit plans’ consolidated assets using significant unobservable inputs (Level 3) between January 1, 2016 and December 31, 2017 is as follows: (millions) Fixed Income Other Real Estate Assets Limited Partnerships Total Balance as of January 1, 2016 $ 1 $ 37 $ 106 $ 144 Realized losses — 1 5 6 Unrealized gains — 2 (3 ) (1 ) Purchases, sales and settlements: Purchases — — 1 1 Sales — (2 ) (6 ) (8 ) Settlements — — — — Net transfers into (out of) Level 3 — — — — Balance as of December 31, 2016 $ 1 $ 38 $ 103 $ 142 Realized gains — 1 15 16 Unrealized gains (losses) — 2 (1 ) 1 Purchases, sales and settlements: Purchases — — 9 9 Sales — (2 ) (35 ) (37 ) Settlements — — — — Net transfers into (out of) Level 3 — — — — Balance as of December 31, 2017 $ 1 $ 39 $ 91 $ 131 CASH FLOWS We are evaluating our level of funding for pension plans and currently estimate that we will contribute approximately $63 million to our pension plans in 2018 . Our cash payments for postretirement plans are estimated to be $9 million in 2018 . Total benefit payments we expect to make to participants, which include payments funded from USG’s assets as well as payments from our pension plans' assets, are as follows (in millions): Years ended December 31 Pension Benefits Postretirement Benefits 2018 $ 120 $ 9 2019 125 9 2020 137 8 2021 134 8 2022 141 8 2023 - 2027 634 42 DEFINED CONTRIBUTION PLANS Total charges for our defined contribution plans amounted to approximately $8 million , $5 million and $6 million for the years ended December 31, 2017 , 2016 and 2015 , respectively. USG’s contributions are charged to cost of products sold and selling and administrative expenses.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation We grant share-based compensation to eligible participants under our 2016 Long-Term Incentive Plan, or New LTIP, which was approved by our Board of Directors and stockholders in 2016, and prior thereto under our Long-Term Incentive Plan, which, together with the New LTIP, is referred to as the LTIP. As of December 31, 2017 , a total of 7 million shares of common stock were reserved for future grants under the New LTIP. The New LTIP authorizes the Board’s Compensation and Organization Committee to provide equity-based compensation in the form of stock options, stock appreciation rights, or SARs, restricted stock, restricted stock units, or RSUs, market share units, or MSUs, performance shares and units, and other cash incentive and share-based awards for the purpose of providing our employees, officers and non-employee directors incentives and rewards for performance. We may issue shares of our common stock upon option exercises and upon the vesting or grant of other awards under the LTIP from our authorized but unissued shares or from treasury shares. Our expense in continuing operations for share-based arrangements was $18 million in 2017 , $ 18 million in 2016 and $ 14 million in 2015 and is included in "Selling and administrative expenses" in our consolidated statements of income. No net income tax effects were recognized for share-based arrangements in the consolidated statements of income in 2017 , 2016 and 2015 . Certain employees of L&W previously received grants of MSUs, performance shares and RSUs. On October 31, 2016, any unvested awards were forfeited upon the sale of L&W and are included as forfeited in the respective tables below. The expense associated with these awards was $ 1 million for 2016 and 2015 and is included in "(Loss) income from discontinued operations" in our consolidated statements of income. MARKET SHARE UNITS We granted MSUs with the following weighted average grant date fair values: 2017 2016 2015 Weighted average grant date fair values $ 35.79 $ 19.59 $ 30.06 MSUs generally vest after a three -year period based on our actual stock price performance during such period. The number of MSUs earned will vary from 0% to 150% of the number of MSUs awarded depending on the actual performance of our stock price. In the case of termination of employment due to death, disability or retirement during the performance period, vesting will be pro-rated based on the number of full months employed in the grant year. Awards earned will be issued at the end of the three -year period. MSUs may vest earlier in the case of a change in control in most circumstances only if there is also a related loss of employment or diminution of duties. Each MSU earned will be settled in shares of our common stock. We estimated the fair value of each MSU granted on the date of grant using a Monte Carlo simulation that used the assumptions noted in the following table. Volatility was based on stock price history immediately prior to grant for a period commensurate with the expected term. The risk-free rate was based on zero-coupon U.S. government issues at the time of grant. The expected term represents the period from the valuation date to the end of the performance period. Assumptions: 2017 2016 2015 Expected volatility 32.10 % 34.02 % 42.70 % Risk-free rate 1.39 % 0.86 % 1.09 % Expected term (in years) 2.96 2.95 2.95 Expected dividends — — — Nonvested MSUs outstanding as of December 31, 2017 and MSU activity during 2017 were as follows: Number of MSUs (000) Weighted Average Grant Date Fair Value Nonvested at January 1, 2017 1,157 $ 23.39 Granted 371 35.79 Vested (417 ) 30.06 Forfeited (14 ) 26.20 Nonvested at December 31, 2017 1,097 25.01 With respect to the MSUs granted in 2015 , for which the three -year period ended December 31, 2017 , 417,001 vested for approximately 554,624 shares of common stock based on the actual performance of our stock price. Total unrecognized compensation cost related to nonvested share-based compensation awards represented by MSUs granted under the LTIP was $ 5 million as of December 31, 2017 . We expect that cost to be recognized over a weighted average period of 1.7 years. PERFORMANCE SHARES We granted performance shares with the following weighted average grant date fair values: 2017 2016 2015 Weighted average grant date fair values $ 39.42 $ 21.10 $ 30.63 The performance shares generally vest after a three -year period based on our total stockholder return relative to the performance of the Dow Jones U.S. Construction and Materials Index, with adjustments to that index in certain circumstances, for the three-year period. The number of performance shares earned will vary from 0% to 200% of the number of performance shares awarded depending on that relative performance. Vesting will be pro-rated based on the number of full months employed during the performance period in the case of death, disability, retirement or a change in control, and pro-rated awards earned will be settled in common stock at the end of the three -year period. We estimated the fair value of each performance share granted on the date of grant using a Monte Carlo simulation that uses the assumptions noted in the following table. Volatility was based on stock price history immediately prior to grant for a period commensurate with the expected term. The risk-free rate was based on zero-coupon U.S. government issues at the time of grant. The expected term represents the period from the grant date to the end of the three -year performance period. Assumptions: 2017 2016 2015 Expected volatility 32.10 % 34.02 % 42.70 % Risk-free rate 1.39 % 0.86 % 1.09 % Expected term (in years) 2.96 2.95 2.95 Expected dividends — — — Nonvested performance shares outstanding as of December 31, 2017 and performance share activity during 2017 were as follows: Number of Performance Shares (000) Weighted Average Grant Date Fair Value Nonvested at January 1, 2017 246 $ 24.98 Granted 113 39.42 Vested (99 ) 30.63 Forfeited (4 ) 26.75 Nonvested at December 31, 2017 256 29.14 With respect to the performance shares granted in 2015 , for which the three -year performance period ended December 31, 2017 , 99,238 of the performance awards vested for no common shares. Total unrecognized compensation cost related to nonvested share-based compensation awards represented by performance shares granted under the LTIP was $4 million as of December 31, 2017 . We expect that cost to be recognized over a weighted average period of 1.8 years. RESTRICTED STOCK UNITS We granted RSUs with the following weighted average grant date fair values: 2017 2016 2015 Weighted average grant date fair values $ 31.57 $ 23.94 $ 28.56 RSUs granted as special retention awards, including those granted in 2017 , generally vest after a specified number of years from the date of grant or at a specified date and RSUs granted with performance goals vest if those goals are attained. RSUs may vest earlier in the case of death, disability, retirement or a change in control. Each RSU is settled in a share of our common stock after the vesting period. The fair value of each RSU granted is equal to the closing market price of our common stock on the date of grant. The RSUs granted in 2017 were special retention awards that generally vest in three years from the date of grant. RSUs outstanding as of December 31, 2017 and RSU activity during the year then ended were as follows: Number of RSUs (000) Weighted Average Grant Date Fair Value Nonvested at January 1, 2017 228 $ 27.31 Granted 133 31.57 Vested (54 ) 31.38 Forfeited (3 ) 29.83 Nonvested at December 31, 2017 304 14.67 As of December 31, 2017 , there was $5 million of total unrecognized compensation cost related to nonvested share-based compensation awards represented by RSUs granted under the LTIP. We expect that cost to be recognized over a weighted average period of 2.2 years . The total fair value of RSUs that vested was $2 million during 2017 , $ 2 million during 2016 and $ 4 million during 2015 . STOCK OPTIONS We last granted stock options in 2012. All outstanding stock options are exercisable. The stock options generally expire ten years from the date of grant, or earlier in the event of death, disability or retirement. A summary of stock options outstanding as of December 31, 2017 and of stock option activity during the year then ended is presented below: Number of Options (000) Weighted Average Exercise Price Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value (millions) Outstanding at January 1, 2017 2,174 $ 22.55 2.78 $ 22 Exercised (590 ) 23.88 Canceled (323 ) 46.80 Outstanding at December 31, 2017 1,261 $ 15.72 2.48 $ 28 Exercisable at December 31, 2017 1,261 $ 15.72 2.48 $ 28 Vested at December 31, 2017 1,261 $ 15.72 2.48 $ 28 (millions) 2017 2016 2015 Intrinsic value of stock options exercised $ 7 $ 4 $ 6 Cash received from stock options exercised $ 14 $ 4 $ 6 Fair value of stock options vested $ — $ 1 $ 1 Intrinsic value for stock options is defined as the difference between the current market value of our common stock and the exercise price of the stock options. NON-EMPLOYEE DIRECTOR DEFERRED STOCK UNITS Our non-employee directors may elect to receive a portion of their compensation as deferred stock units. In August 2017, we amended this program to remove the election to receive cash or shares of USG common stock upon termination of board service and, as a result, all deferred stock units granted after August 2017 will be paid in shares of USG common stock. Also in August 2017, four of our non-employee directors elected to receive shares of stock for previously granted deferred stock units, and as a result, in 2017, we recorded a reclassification from a liability to equity of $6 million for these previously deferred awards.

Supplemental Balance Sheet Info

Supplemental Balance Sheet Information	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Balance Sheet Information	Supplemental Balance Sheet Information INVENTORIES Inventories as of December 31 consisted of the following: (millions) 2017 2016 Finished goods $ 140 $ 132 Work in progress 39 37 Raw materials 73 67 Total $ 252 $ 236 PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment as of December 31 consisted of the following: (millions) 2017 2016 Land and mineral deposits $ 120 $ 116 Buildings and improvements 1,100 1,078 Machinery and equipment 2,595 2,473 3,815 3,667 Reserves for depreciation and depletion (2,053 ) (1,960 ) Total $ 1,762 $ 1,707 Annual depreciation and depletion expense $ 129 $ 129 ACCRUED EXPENSES Accrued expenses as of December 31 consisted of the following: (millions) 2017 2016 Self-insurance reserves $ 12 $ 12 Employee compensation 17 35 Interest 12 31 Derivatives 9 5 Pension and other postretirement benefits 17 24 Environmental 17 18 Other 51 50 Total $ 135 $ 175 ASSET RETIREMENT OBLIGATIONS Changes in our liability for asset retirement obligations consisted of the following: (millions) 2017 2016 Balance as of January 1 $ 113 $ 119 Accretion expense 7 7 Liabilities incurred 3 2 Changes in estimated cash flows (a) (4 ) (12 ) Liabilities settled (3 ) (4 ) Foreign currency translation 2 1 Balance as of December 31 $ 118 $ 113 (a) Changes in estimated cash flows for the year ended December 31, 2016 includes a $8 million reduction related to one of our quarries. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) Changes in the balances of each component of accumulated other comprehensive income (loss), or AOCI, are summarized in the following table: (millions) Derivatives Pension and Other Postretirement Benefit Plans Foreign Total AOCI Balance as of January 1, 2015 $ 16 $ (302 ) $ (52 ) $ (338 ) Other comprehensive income (loss) before reclassifications, net of tax (5 ) 74 (67 ) 2 Less: Amounts reclassified from AOCI, net of tax (9 ) (7 ) (6 ) (22 ) Other comprehensive income (loss), net of tax 4 81 (61 ) 24 Balance as of December 31, 2015 $ 20 $ (221 ) $ (113 ) $ (314 ) Other comprehensive income (loss) before reclassifications, net of tax 1 (34 ) (53 ) (86 ) Less: Amounts reclassified from AOCI, net of tax (6 ) (9 ) — (15 ) Other comprehensive income (loss), net of tax 7 (25 ) (53 ) (71 ) Balance as of December 31, 2016 $ 27 $ (246 ) $ (166 ) $ (385 ) Other comprehensive income (loss) before reclassifications, net of tax (14 ) (65 ) 58 (21 ) Less: Amounts reclassified from AOCI, net of tax (3 ) (14 ) — (17 ) Other comprehensive income (loss), net of tax (11 ) (51 ) 58 (4 ) Balance as of December 31, 2017 $ 16 $ (297 ) $ (108 ) $ (389 ) Amounts reclassified from AOCI, net of tax, for the years ended December 31, 2017 , 2016 and 2015 were as follows: (millions) 2017 2016 2015 Derivatives Net reclassification from AOCI for cash flow hedges included in cost of products sold $ (6 ) $ (10 ) $ (8 ) Net reclassification from AOCI for cash flow hedges included in income and gain from the sale of equity method investment to related party — — 1 Less: Income tax (benefit) expense on reclassification from AOCI included in income tax expense (3 ) (4 ) 2 Net amount reclassified from AOCI $ (3 ) $ (6 ) $ (9 ) Pension and postretirement benefits Net reclassification from AOCI for amortization of prior service (benefit) cost included in cost of products sold $ (8 ) $ (1 ) $ 1 Net reclassification from AOCI for amortization of prior service benefit included in selling and administrative expenses (5 ) (12 ) (5 ) Net reclassification from AOCI for amortization of prior service benefit included in (loss) income from and gain on sale of discontinued operations (11 ) (3 ) (4 ) Less: Income tax expense on reclassification from AOCI included in income tax expense (10 ) (7 ) (1 ) Net amount reclassified from AOCI $ (14 ) $ (9 ) $ (7 ) Foreign Currency Translation Net reclassification from AOCI for translation loss realized upon the sale of foreign entities $ — $ — $ (6 ) Net amount reclassified from AOCI $ — $ — $ (6 ) We estimate that we will reclassify a net $6 million after-tax loss on derivatives from AOCI to earnings within the next 12 months.

Long-Lived Asset Impairment Cha

Long-Lived Asset Impairment Charges	12 Months Ended
	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Long-Lived Asset Impairment Charges	Long-Lived Asset Impairment Charges In 2016, we indefinitely idled our mining operations in Little Narrows, Nova Scotia, Canada after completing a review of our gypsum sourcing needs. At such time, we assessed the property, plant and equipment for potential impairment. We compared the carrying values of those assets with their future undiscounted cash flows for their remaining useful lives. We measured the fair value of the machinery, equipment and buildings using measurements classified as Level 3, as a result we recorded long-lived asset impairment charges of $10 million , which are included in our consolidated statements of income in "Long-lived asset impairment charges". We also recorded severance and other charges of $2 million for the termination of employees at the Little Narrows location, which are included in "Costs of products sold" on our consolidated statements of income. Both the impairment and severance charges are included in Other. Gypsum Transportation Limited In the second quarter of 2015, we sold our two self-unloading ocean vessels previously owned by Gypsum Transportation Limited, or GTL, for $42 million and recorded a gain of $7 million on the disposition and incurred charges of $6 million to exit our shipping operations. The net impact of the gain on the sale of the vessels and charges incurred to exit the shipping operations of $1 million is recorded in “Gain on disposal of shipping operations, net” on the consolidated statement of income. In November 2015, we entered into a release and debt settlement agreement to recover a portion of our loss incurred when our former trading partner ceased performing under the contract. We recorded a recovery of $6 million in 2015 and it is presented within the "Recovery of receivable" on our consolidated statements of income. We received an additional $8 million for the recovery in 2016, of which $3 million is recorded within "Recovery of receivable," $1 million is recorded within "Interest income" and $4 million is recorded within "Other (expense) income, net" on our consolidated statements of income. GTL recorded operating profit of $0 million , $3 million and $7 million in 2017, 2016 and 2015 , respectively, which is reflected within Other.

Gypsum Transportation Limited

Gypsum Transportation Limited	12 Months Ended
	Dec. 31, 2017
Restructuring and Related Activities [Abstract]
Gypsum Transportation Limited	Long-Lived Asset Impairment Charges In 2016, we indefinitely idled our mining operations in Little Narrows, Nova Scotia, Canada after completing a review of our gypsum sourcing needs. At such time, we assessed the property, plant and equipment for potential impairment. We compared the carrying values of those assets with their future undiscounted cash flows for their remaining useful lives. We measured the fair value of the machinery, equipment and buildings using measurements classified as Level 3, as a result we recorded long-lived asset impairment charges of $10 million , which are included in our consolidated statements of income in "Long-lived asset impairment charges". We also recorded severance and other charges of $2 million for the termination of employees at the Little Narrows location, which are included in "Costs of products sold" on our consolidated statements of income. Both the impairment and severance charges are included in Other. Gypsum Transportation Limited In the second quarter of 2015, we sold our two self-unloading ocean vessels previously owned by Gypsum Transportation Limited, or GTL, for $42 million and recorded a gain of $7 million on the disposition and incurred charges of $6 million to exit our shipping operations. The net impact of the gain on the sale of the vessels and charges incurred to exit the shipping operations of $1 million is recorded in “Gain on disposal of shipping operations, net” on the consolidated statement of income. In November 2015, we entered into a release and debt settlement agreement to recover a portion of our loss incurred when our former trading partner ceased performing under the contract. We recorded a recovery of $6 million in 2015 and it is presented within the "Recovery of receivable" on our consolidated statements of income. We received an additional $8 million for the recovery in 2016, of which $3 million is recorded within "Recovery of receivable," $1 million is recorded within "Interest income" and $4 million is recorded within "Other (expense) income, net" on our consolidated statements of income. GTL recorded operating profit of $0 million , $3 million and $7 million in 2017, 2016 and 2015 , respectively, which is reflected within Other.

Segments

Segments	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segments	Segments During the fourth quarter of 2017, as part of the realignment of our operating structure, we changed the composition of our reportable segments, effective for the quarter ended December 31, 2017. See Note 1, Significant Accounting Policies, for additional information regarding the changes to our reportable segments. The results of our five reportable segments are as follows: CONSOLIDATED SEGMENTS For the year ended December 31, (millions) 2017 2016 2015 Net Sales: U.S. Wallboard and Surfaces $ 1,916 $ 1,778 $ 1,720 U.S. Performance Materials 373 357 321 U.S. Ceilings 477 467 464 Canada 405 389 372 Other 245 220 239 Eliminations (212 ) (194 ) (203 ) Total $ 3,204 $ 3,017 $ 2,913 Operating Profit (Loss): U.S. Wallboard and Surfaces $ 314 $ 334 $ 298 U.S. Performance Materials 26 41 31 U.S. Ceilings 95 101 80 Canada 12 26 10 Other 11 (4 ) 30 Corporate (90 ) (104 ) (94 ) Eliminations (1 ) — — Total $ 367 $ 394 $ 355 Depreciation, Depletion and Amortization: U.S. Wallboard and Surfaces $ 91 $ 87 $ 85 U.S. Performance Materials 9 9 8 U.S. Ceilings 15 15 15 Canada 6 6 6 Other 5 7 8 Corporate 6 10 9 Total $ 132 $ 134 $ 131 Capital Expenditures: U.S. Wallboard and Surfaces $ 104 $ 60 $ 73 U.S. Performance Materials 31 11 4 U.S. Ceilings 17 4 3 Canada 10 4 4 Other 5 3 3 Corporate 1 1 — Total $ 168 $ 83 $ 87 As of December 31, Assets: 2017 2016 2015 U.S. Wallboard and Surfaces $ 1,574 $ 1,540 $ 1,590 U.S. Performance Materials 172 154 147 U.S. Ceilings 307 225 267 Canada 134 124 126 Other 144 135 160 Corporate 856 1,080 1,483 Equity method investments 686 628 682 Assets related to discontinued operations — — 357 Eliminations (22 ) (17 ) (76 ) Total $ 3,851 $ 3,869 $ 4,736 CONSOLIDATED PRODUCT SALES INFORMATION For the year ended December 31, (millions) 2017 2016 2015 Net Sales: Gypsum $ 2,331 $ 2,169 $ 2,105 Performance Materials 373 357 321 Ceilings 509 500 496 Elimination (9 ) (9 ) (9 ) Total $ 3,204 $ 3,017 $ 2,913 CONSOLIDATED GEOGRAPHIC INFORMATION For the year ended December 31, (millions) 2017 2016 2015 Net Sales: United States $ 2,787 $ 2,625 $ 2,524 Canada 406 389 379 Other Foreign 204 189 196 Geographic transfers (193 ) (186 ) (186 ) Total $ 3,204 $ 3,017 $ 2,913 Consolidated long-lived assets, consisting of property, plant and equipment, net, by geographic location were as follows: As of December 31, (millions) 2017 2016 2015 Long-Lived Assets: United States $ 1,604 $ 1,563 $ 1,605 Canada 90 80 90 Other Foreign 68 64 76 Total $ 1,762 $ 1,707 $ 1,771 UBBP For the year ended December 31, (millions) 2017 2016 2015 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 As of December 31, 2017 2016 2015 Assets $ 1,419 $ 1,292 $ 1,303 UBBP GEOGRAPHIC INFORMATION For the year ended December 31, (millions) 2017 2016 2015 Net Sales: Australia $ 431 $ 381 $ 345 South Korea 287 223 200 Thailand 150 141 145 China 119 103 120 Other 271 255 234 Geographic Transfers (58 ) (51 ) (41 ) Total $ 1,200 $ 1,052 $ 1,003 Long-lived assets, consisting of property, plant and equipment, net, by geographic location for UBBP were as follows: As of December 31, (millions) 2017 2016 2015 Long-Lived Assets: Australia $ 229 $ 217 $ 216 South Korea 123 107 106 China 101 97 116 Oman 85 86 103 Thailand 86 75 72 Other 86 71 67 Total $ 710 $ 653 $ 680 OTHER SEGMENT INFORMATION Segment operating profit (loss) includes all costs and expenses directly related to the segment involved and an allocation of expenses that benefit more than one segment. Revenues are attributed to geographic areas based on the location of the assets producing the revenues. Transactions between reportable segments and geographic areas are accounted for at transfer prices that are approximately equal to market value. Geographic transfers largely reflect intercompany sales from our domestic segments of U.S. Wallboard and Surfaces, U.S. Performance Materials and U.S. Ceilings to Canada and Mexico. Sales to our significant customers were as follows: Significant Customer Segment with Sales to Significant Customer 2017 2016 2015 The Home Depot U.S. Wallboard and Surfaces, U.S. Performance Materials, U.S. Ceilings, and Canada 23 % 23 % 23 % L&W U.S. Wallboard and Surfaces, U.S. Performance Materials and U.S. Ceilings 16 % 19 % 18 %

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On December 22, 2017, the President of the United States signed into law the Tax Cuts and Jobs Act, or the 2017 Tax Act. The 2017 Tax Act amends the Internal Revenue Code to reduce tax rates and modify policies, credits and deductions. For businesses, the 2017 Tax Act reduces the corporate federal tax rate from a maximum of 35% to a flat 21% . The provisional effect on deferred tax assets and liabilities of the change in tax rates was recognized in earnings in the period ended December 31, 2017, which was when the change was enacted. As part of the 2017 Tax Act's change to a quasi-territorial system, a transition tax was imposed on our accumulated foreign earnings, partially offset by foreign tax credits, which was also recognized in the period ending December 31, 2017. The 2017 Tax Act made significant changes to how foreign tax credits may be realized to offset future tax liabilities. Further clarity may change our anticipated realization of our foreign tax credits. In addition, we may make an election to forgo the use of net operating losses, or NOLs, to offset the impact of the transition tax as allowed under the 2017 Tax Act. Due to the timing of the enactment and the complexity involved in applying the provisions of the 2017 Tax Act, we have made reasonable estimates of the effects and recorded provisional amounts in our financial statements as of December 31, 2017. As we collect and prepare necessary data, and interpret the 2017 Tax Act and any additional guidance issued by the U.S. Treasury Department, the IRS, and other standard-setting bodies, we may make adjustments to the provisional amounts. The 2017 Tax Act also repealed the corporate alternative minimum tax, or AMT, for tax years beginning January 1, 2018, and provides that existing AMT credit carryovers are refundable beginning in 2018. We have approximately $32 million of AMT credit carryovers, net of our estimate of anticipated sequestration reduction, that are expected to be refunded by 2022. As of December 31, 2017, we recorded a $12 million receivable, which is included in "Income taxes receivable" on our consolidated balance sheet. Income from continuing operations before income taxes consisted of the following: (millions) 2017 2016 2015 U.S. $ 272 $ 201 $ 152 Foreign 63 73 84 Total $ 335 $ 274 $ 236 Income tax expense (benefit) on continuing operations consisted of the following: (millions) 2017 2016 2015 Current: Federal $ (21 ) $ — $ — Foreign 2 5 12 State 2 1 1 Total current $ (17 ) $ 6 $ 13 Deferred: Federal $ 243 $ 41 $ (631 ) Foreign — 2 (4 ) State 12 14 (118 ) Total deferred $ 255 $ 57 $ (753 ) Total $ 238 $ 63 $ (740 ) For our continuing operations, differences between actual provisions for income taxes and provisions for income taxes at the U.S. federal statutory rate ( 35% ), prior to changes under the 2017 Tax Act, were as follows: (millions) 2017 2016 2015 Taxes on income from continuing operations at U.S. federal statutory rate $ 117 $ 96 $ 82 Foreign earnings subject to different tax rates (a) 3 (3 ) (3 ) State income tax, net of federal benefit 9 10 8 Change in valuation allowance — — (827 ) Income from equity method investments (b) (21 ) (17 ) (16 ) Law changes (c) 145 — — Prior year return adjustments (7 ) — — Benefits from unrecognized tax positions — — (6 ) Foreign tax credits — (21 ) — Tax expense on distribution of foreign earnings — — 20 Other, net (8 ) (2 ) 2 Provision for income tax expense (benefit) $ 238 $ 63 $ (740 ) Effective income tax rate 71.0 % 22.9 % (313.6 )% (a) Foreign earnings subject to different tax rates includes amounts related to impairments and other charges associated with our former shipping operations. (b) Included in income from equity method investments are taxes associated with that income in the respective jurisdictions. These taxes, which are predominately foreign statutory rates, are at rates that are lower than the U.S. federal statutory rate. (c) The impact of the 2017 Tax Act included the transition tax on deferred foreign earnings, net of foreign tax credits, of $9 million , an increase in the valuation allowance related to foreign tax credits of $106 million , an increase in the valuation allowance of our state NOLs due to the change in federal benefit related to those assets of $18 million , anticipated sequestration of our AMT credits of $3 million and the impact of the corporate rate change on deferred tax assets and liabilities of $9 million . Significant components of deferred tax assets and liabilities were as follows: As of December 31, (millions) 2017 2016 Deferred Tax Assets: Net operating loss and tax credit carryforwards $ 477 $ 599 Pension and postretirement benefits 86 112 Reserves not deductible until paid 14 20 Self insurance 2 2 Capitalized interest 7 13 Inventories 4 6 Share-based compensation 14 28 Other 7 4 Deferred tax assets before valuation allowance 611 784 Valuation allowance (175 ) (51 ) Total deferred tax assets $ 436 $ 733 Deferred Tax Liabilities: Property, plant and equipment 153 245 Other — — Total deferred tax liabilities $ 153 $ 245 Net deferred tax assets $ 283 $ 488 During 2017, we recorded an increase in the valuation allowance against our deferred tax assets of $124 million . The increase was primarily related to law changes under the 2017 Tax Act, including the federal rate change, from 35% to 21%, and the ability to realize foreign tax credits. As of December 31, 2017 , we had net deferred tax assets of $283 million , which included a valuation allowance of $175 million . The components of the valuation allowance relate to certain state NOL carryforwards and foreign tax credit carryforwards that we anticipate will not be used prior to their expiration. Our ability to realize our deferred tax assets, including our foreign tax credit carryforwards, is subject to further clarification of the 2017 Tax Act. As a result, the actual impact on the realizability of our net deferred tax assets may vary from the estimated amount due to uncertainties in our preliminary assessment and estimate. As of December 31, 2017 , we had federal NOL carryforwards of approximately $477 million that are available to offset future federal taxable income and will expire in the years 2030 through 2032 . In addition, as of that date, we had federal AMT credit carryforwards of approximately $20 million that are available to reduce future regular federal income taxes with the full benefit being realized by 2022 as described in the 2017 Tax Act. We have foreign tax credit carryforwards of $223 million that are available to offset future federal taxable income and expire in the years 2022 through 2027. The foreign tax credits are attributable to tax planning strategies to optimize foreign tax credit utilization and management’s intention to amend its tax returns for the tax years 2012-2013 in order to claim credits for previously deducted foreign tax. In 2017, additional foreign tax credits were attributed to the transition tax as enacted by the 2017 Tax Act. The calculation of the foreign tax credit carryforwards and our ability to use them in the future is based on currently available information and is subject to revaluation as further clarification on the new law is available. In order to fully realize the U.S. federal net deferred tax assets, taxable income of approximately $1.663 billion would need to be generated during the period before their expiration based on our current interpretation of the 2017 Tax Act. As of December 31, 2017 , we had a deferred tax asset of $169 million related to state NOLs and tax credit carryforwards. The NOLs will expire if unused in years 2018 through 2036 . To the extent that we do not generate sufficient state taxable income within the statutory carryforward periods to utilize the NOL and tax credit carryforwards in these states, they will expire unused. In 2016, we recorded a decrease in the valuation allowance against our deferred tax assets of $19 million which was related to the expiration of state Net Operating Loss (NOL) carryforwards. In 2015, we reversed $731 million of our valuation allowance. We considered all positive and negative evidence and gave more weight to evidence that was objective in nature as compared to subjective evidence. Significant weight was given to evidence that directly relates to our current financial performance. As of December 31, 2015, we emerged from a four-year cumulative pre-tax loss and had five consecutive quarters of domestic pre-tax earnings. The recent domestic pre-tax operating earnings was a significant, principal piece of positive evidence, which was weighed with the underlying momentum in the business, and generally improved market and economic conditions. Other evidence included strategic actions taken by management to lower costs and our expected utilization of deferred tax assets. All of this positive evidence lead to the determination that December 31, 2015 was the appropriate time to reverse a significant portion of the valuation allowance. The Internal Revenue Code imposes limitations on a corporation’s ability to utilize NOLs if it experiences an “ownership change,” which can result from transactions increasing the ownership of certain stockholders in the stock of a corporation by more than 50 percentage points over a three -year period. If we were to experience an ownership change, utilization of our NOLs would be subject to an annual limitation that may be carried over to later years within the allowed NOL carryforward period. Over the entire carryforward period, we may not be able to use all our NOLs due to the aforementioned annual limitation. If an ownership change had occurred as of December 31, 2017 , our annual U.S. federal NOL utilization would have been limited to approximately $107 million per year. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: (millions) 2017 2016 2015 Balance as of January 1 $ 15 $ 18 $ 22 Tax positions related to the current period: Gross increase — — 4 Gross decrease — — — Tax positions related to prior periods: Gross increase — — — Gross decrease (1 ) (3 ) (1 ) Settlements — — (6 ) Lapse of statutes of limitations (2 ) — (1 ) Balance as of December 31 $ 12 $ 15 $ 18 We classify interest expense and penalties related to unrecognized tax benefits and interest income on tax overpayments as components of income taxes (benefit). We do no t have amounts related to interest expense and penalties recognized on our consolidated balance sheets as of December 31, 2017 and had $2 million as of December 31, 2016 . We recorded no interest and penalties in our consolidated statements of income in each of the three years ended December 31, 2017 , 2016 and 2015 . The total amounts of unrecognized tax benefit that, if recognized, would affect our effective tax rate were $12 million , $14 million and $17 million for 2017 , 2016 and 2015 , respectively. Our federal income tax return for 2014 is currently under examination by the Internal Revenue Service, or IRS. Our federal income tax returns for 2008 and prior years have been examined by the IRS. The U.S. federal statute of limitations remains open for 2006 -2012 and 2014 to the present. We are under examination in various U.S. state and foreign jurisdictions. We do not believe our gross unrecognized tax benefits will change as a result of the conclusion of these examinations. There are statutes, however, that are expiring within the next 12 months that could result in recognition of approximately $2 million of tax benefit. Foreign and U.S. state jurisdictions have statutes of limitations generally ranging from three to five years. We do not provide for U.S. income taxes on the portion of undistributed earnings of foreign subsidiaries that is intended to be permanently reinvested. It is not practical to calculate the residual income tax which would result if basis differences reversed due to the complexities of the tax law impacted by the 2017 Tax Act and the hypothetical nature of the calculations. Our reevaluation of our permanently reinvested assertion is subject to further clarification of the 2017 Tax Act, the impact of which cannot be estimated at this time.

Stockholder Rights Plan

Stockholder Rights Plan	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Stockholder Rights Plan	Stockholder Rights Plan NOL Protective Provisions of our Rights Plan We have a stockholder rights plan that is intended to protect our substantial NOL carryforwards and related tax benefits. See Note 15 for a description of our NOL carryforwards. Under federal tax laws, we generally can use our NOLs and certain related tax credits to reduce ordinary income tax paid in our prior two tax years or on our future taxable income for up to 20 years, when they “expire” for such purposes. Our ability to use our NOLs could be substantially limited if we experience an “ownership change,” as defined under Section 382 of the Internal Revenue Code of 1986, as amended (the "Code"), and the rights plan has been designed to help prevent such an “ownership change.” Under Section 382 of the Code, an “ownership change” occurs if, over a rolling three -year period, there has been an aggregate increase of 50 percentage points or more in the percentage of our common stock owned by one or more of our “ 5 -percent stockholders” (as determined under Section 382 of the Code). The rights plan provides that if any person becomes the beneficial owner (as defined in the Code) of 4.9% or more of our common stock, stockholders other than the triggering stockholder will have the right to purchase additional shares of our common stock at half the market price, thereby diluting the triggering stockholder; provided that stockholders whose beneficial ownership, as defined in Section 382 of the Code, exceeded 4.9% of our common stock outstanding on February 11, 2015 will not be deemed to have triggered the rights plan, so long as they do not thereafter acquire beneficial ownership of additional common stock other than in certain specified exempt transactions. The rights will expire at the close of business on May 31, 2019, unless earlier redeemed or exchanged. Our Board of Directors has the power to accelerate or extend the expiration date of the rights. The NOL protective provisions of the rights plan described above will be effective until the earliest of the close of business on (i) May 31, 2019, (ii) the date on which our Board of Directors determines that these provisions are no longer necessary for the protection of certain tax benefits because of the repeal of Section 382 of the Code, (iii) the first day of a taxable year as to which our Board of Directors determines that no tax benefits may be carried forward, or (iv) such other date as our Board of Directors determines that these provisions are no longer necessary for the preservation of tax benefits (the "Special Period"). After the end of the Special Period, the triggering threshold for the rights issued pursuant to the rights plan will revert to 15% of our outstanding common stock and the definition of “beneficial owner” will revert to definitions that do not track Section 382 of the Code. At our 2016 annual meeting our stockholders ratified, on an advisory basis, the extension of the term of the rights plan and the NOL protective provisions described above. A board committee composed solely of independent directors reviews the rights plan at least once every three years to determine whether to modify the rights plan in light of all relevant factors. This review was most recently conducted in November 2015. The next review is required by the end of 2018. Restated Certificate of Incorporation Our Restated Certificate of Incorporation also restricts certain transfers of our common stock and includes provisions intended to further protect the tax benefits of our NOL carryforwards. Subject to certain limited exceptions, these transfer restrictions restrict any person from transferring our common stock (or any interest in our common stock) if the transfer would result in a stockholder (or several stockholders, in the aggregate, who hold their stock as a “group” under Section 382 of the Code) owning 4.9% or more of our common stock. Any direct or indirect transfer attempted in violation of these transfer restrictions would be void as of the date of the prohibited transfer as to the purported transferee, and the purported transferee would not be recognized as the owner of the shares attempted to be owned in violation of the transfer restrictions for any purpose, including for purposes of voting and receiving dividends or other distributions in respect of that common stock, or in the case of options, receiving our common stock in respect of their exercise. These restrictions are effective until the earliest of (i) the close of business on May 31, 2019, (ii) the repeal of Section 382 of the Code if our Board of Directors determines that the restrictions are no longer necessary or desirable for the preservation of tax benefits, (iii) the close of business on the first day of a taxable year as to which our Board of Directors determines that no tax benefits may be carried forward, or (iv) such other date as determined by our Board of Directors pursuant to the provisions described above. Treatment of Berkshire Hathaway under Rights Plan and Restated Certificate of Incorporation Pursuant to a Shareholder’s Agreement reached in 2006, Berkshire Hathaway and certain of its affiliates may acquire beneficial ownership of up to 50% of our voting stock on a fully-diluted basis without triggering the ownership thresholds in our Restated Certificate of Incorporation or the rights plan, and may acquire beneficial ownership of more than 50% of our voting stock on a fully-diluted basis without triggering the ownership thresholds in our Restated Certificate of Incorporation or the rights plan through an offer to purchase all of our common stock that remains open for at least 60 days, in each case subject to specified exceptions.

Lease Commitments

Lease Commitments	12 Months Ended
	Dec. 31, 2017
Lease Commitments [Abstract]
Lease Commitments	Lease Commitments We lease some of our offices, buildings, machinery and equipment, and autos under noncancelable operating leases. These leases have various escalation terms and renewal options. Lease expense amounted to $38 million in 2017 , $37 million in 2016 and $36 million in 2015 . Future minimum lease payments required under operating leases with initial or remaining noncancelable terms in excess of one year as of December 31, 2017 were as follows: (millions) 2018 2019 2020 2021 2022 After 2022 Future minimum lease payments $ 36 $ 31 $ 25 $ 19 $ 10 $ 9

Litigation

Litigation	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Litigation	Litigation WALLBOARD PRICING CLASS ACTION LAWSUITS In 2015, USG, our subsidiary United States Gypsum Company, our former subsidiary L&W Supply Corporation, and seven other wallboard manufacturers were named as defendants in a lawsuit filed in federal court in California by twelve homebuilders alleging that since at least September 2011, U.S. wallboard manufacturers conspired to fix and raise the price of gypsum wallboard sold in the United States and to effectuate the alleged conspiracy by ending the practice of providing job quotes on wallboard. The lawsuit was transferred to the United States District Court for the Eastern District of Pennsylvania under the title In re: Domestic Drywall Antitrust Litigation, MDL No. 2437. In the second quarter of 2016, the Court dismissed with prejudice the portions of the homebuilders’ complaint alleging a conspiracy in 2014 and 2015, ruling that there were insufficient factual allegations to allow such a claim to go forward. The homebuilders' claims alleging a conspiracy prior to 2014 have not been dismissed, and the case proceeds as to those claims. USG has agreed to defend and indemnify L&W Supply Corporation with regard to this matter. Beginning in the third quarter of 2013, class action lawsuits making similar allegations with regard to Canada were filed in Quebec, Ontario and British Columbia courts on behalf of purchasers of wallboard in Canada and naming USG, United States Gypsum Company, CGC Inc., and other wallboard manufacturers as defendants. We believe that the cost, if any, of resolving the homebuilders’ lawsuit and Canadian class action litigation will not have a material effect on our results of operations, financial position or cash flows. ENVIRONMENTAL LITIGATION We are involved in environmental cleanups of property that we own or have owned. In addition, we have been notified by state and federal environmental protection agencies of possible involvement as one of numerous “potentially responsible parties” in certain Superfund sites in the United States to pay for some part of the cleanup of hazardous waste. In most of these sites, our involvement is expected to be minimal. As of December 31, 2017 and December 31, 2016 , we had an accrual of $17 million and $18 million , respectively, for our probable and reasonably estimable liability in connection with these matters. Our accruals take into account all known or estimated undiscounted costs associated with these sites, including site investigations and feasibility costs, site cleanup and remediation, certain legal costs, and fines and penalties, if any. However, we continue to review these accruals as additional information becomes available and revise them as appropriate. Based on the information known to us, we believe these environmental matters will not have a material effect on our results of operations, financial position or cash flows. OTHER LITIGATION We are named as defendants in other claims and lawsuits arising from our operations, including lawsuits or claims arising from commercial disputes, product performance, product liabilities and worksite or vehicular accidents. We believe that we have properly accrued for our probable liability in connection with these claims and suits, taking into account the probability of liability, whether our exposure can be reasonably estimated and, if so, our estimate of our liability or the range of our liability. We do not expect these or any other litigation matters involving USG to have a material effect on our results of operations, financial position or cash flows.

Quarterly Financial Data (unaud

Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (unaudited)	Quarterly Financial Data (unaudited) Quarter (millions, except per-share data) First Second Third Fourth 2017 Net sales $ 767 $ 811 $ 795 $ 831 Gross profit 164 168 163 170 Operating profit 91 96 93 87 Income (loss) from continuing operations (b) 55 46 66 (70 ) (Loss) income from discontinued operations, net of tax — (10 ) — 1 Net income (loss) (b) 55 36 66 (69 ) Income per average common share: Basic (a) $ 0.38 $ 0.25 $ 0.47 $ (0.49 ) Diluted (a) 0.37 0.24 0.46 (0.49 ) 2016 Net sales $ 747 $ 769 $ 767 $ 734 Gross profit 181 193 181 150 Operating profit 116 122 97 59 Income from continuing operations (c) 60 67 56 28 Gain on sale of discontinued operations, net of tax — — — 279 Income from discontinued operations, net of tax 7 7 6 — Net income (c) 67 74 62 307 Income per average common share: Basic (a) $ 0.46 $ 0.50 $ 0.43 $ 2.10 Diluted (a) 0.46 0.50 0.42 2.07 (a) The sum of the four quarters is not necessarily the same as the total for the year. (b) Income from continuing operations and net income included a loss on extinguishment of debt of $22 million for the second quarter of 2017 and income tax expense of $145 million related to the 2017 Tax Act for the fourth quarter of 2017. See Notes 6 and 15, respectively. (c) Income from continuing operations and net income included a loss on extinguishment of debt of $32 million for the fourth quarter of 2016. See Note 6.

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On February 1, 2018, we announced that our Board of Directors approved a $250 million increase to our stock repurchase program, bringing the total authorization to $500 million . Under the program, we may repurchase shares from time to time in open market transactions or in privately-negotiated transactions in accordance with applicable securities laws. We may discontinue the program at any time. The timing and the amount of any repurchases will be determined based on market conditions and other factors. We expect that stock repurchases will be funded with available cash on hand. During 2017, we repurchased $184 million of our common stock, leaving $316 million of authorization remaining.

Schedule II - Valuation And Qua

Schedule II - Valuation And Qualifying Accounts	12 Months Ended
	Dec. 31, 2017
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation And Qualifying Accounts	SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS Additions (millions) Balance at beginning of period Charged to costs and expenses Charged to other accounts Deductions (a) Balance at end of period Year ended December 31, 2017: Doubtful accounts $ 5 $ 2 $ — $ (1 ) $ 6 Cash discounts 3 34 — (34 ) 3 Income tax valuation allowance 51 124 — — 175 Year ended December 31, 2016: Doubtful accounts 7 1 — (3 ) 5 Cash discounts 2 34 — (33 ) 3 Income tax valuation allowance 70 — — (19 ) 51 Year ended December 31, 2015: Doubtful accounts 14 (6 ) — (1 ) 7 Cash discounts 1 37 — (36 ) 2 Income tax valuation allowance 1,023 — — (953 ) 70 (a) Reflects receivables written off as related to doubtful accounts, discounts allowed as related to cash discounts and reductions in the income tax valuation allowance.

Significant Accounting Polici30

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations USG, through our subsidiaries and joint ventures, is a leading manufacturer of building materials and innovative solutions. We produce a wide range of products for use in new residential, new nonresidential, and residential and nonresidential repair and remodel construction as well as products used in certain industrial processes. Our products are distributed through building materials dealers, home improvement centers and other retailers and specialty wallboard distributors and sold directly to contractors.
Segments	Segments During the fourth quarter of 2017, we realigned our operating structure to reflect changes in our organizational structure and management's operation and view of our businesses. Our realigned operating structure is generally aligned by product type and consists of three divisions, in addition to our USG Boral Building Products, or UBBP, our joint ventures in Asia, Australasia and the Middle East: Gypsum, Performance Materials and Ceilings. The operations of the divisions are similar throughout North America. This change to our operating structure modified how the business is managed and the financial information received by the chief operating decision maker to assess operating performance and allocate resources, and thus, triggered a review of our segment structure. Effective for the quarter ended December 31, 2017, we changed the composition of our reportable segments to reflect this change. We now have five reportable segments: U.S. Wallboard and Surfaces, U.S. Performance Materials, U.S. Ceilings, Canada, and UBBP. Our prior period results have been recast to reflect these changes and present comparative year over year information by segment. See Note 14 , Segments. Our reportable segments are determined considering both qualitative and quantitative metrics for aggregation of the product type within geographies for which discrete financial information is available. Our U.S. Wallboard and Surfaces, U.S. Performance Materials and U.S. Ceilings reportable segments were identified based on products manufactured and marketed. Our Canada segment is a separately reportable segment, as while it has similar qualitative factors to U.S. operations, it has different quantitative metrics and, therefore, cannot be aggregated. Our operating segments in Mexico and Latin America, as well as our mining operation in Little Narrows, Nova Scotia, Canada, which we indefinitely idled in 2016, and our shipping company, which we exited in 2015, are now included in Other as reconciling items to our consolidated segments. There has been no change to our UBBP segment.
Consolidation and Presentation	Consolidation and Presentation Our consolidated financial statements include the accounts of USG Corporation and its majority-owned subsidiaries. Entities in which we have more than a 20% but not more than 50% ownership interest are accounted for using the equity method of accounting. All intercompany balances and transactions are eliminated in consolidation. Certain other reclassifications have been made to prior year amounts in order to conform with current year presentation. On our consolidated balance sheet, we reclassified the balance of our intangible assets from '"Other assets" to "Goodwill and intangible assets."
Use of Estimates	Use of Estimates The preparation of our consolidated financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets, liabilities, revenues and expenses. Actual results could differ from these estimates.
Revenue Recognition	Revenue Recognition We recognize revenue when shipment is received by the customer. We enter into agreements with customers to offer rebates, generally based on achievement of specified sales levels and various marketing allowances that are common industry practice. Estimated reductions to revenue for customer programs and incentive offerings, including promotions and other volume–based incentives, are recorded in the period in which the sale occurs. Provisions for early payment discounts are accrued in the same period in which the sale occurs.
Shipping and Handling Costs	Shipping and Handling Costs Shipping and handling costs billed to customers are included in net sales and the related costs are presented in cost of products sold.
Advertising	Advertising Advertising expenses consist of media advertising and related production costs and sponsorships. We charge advertising expenses to earnings as incurred.
Research and Development	Research and Development We charge research and development expenditures to earnings as incurred.
Litigation Costs	Legal Costs We expense legal costs as incurred.
Income Taxes	Income Taxes We record income tax expense (benefit) under the asset and liability method. Under this method, deferred tax assets and liabilities are recognized based on temporary differences between the financial statement carrying values of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply in the years in which the temporary differences are expected to be recovered or paid. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in earnings in the period when the change is enacted. Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not that a tax benefit will not be realized. A reduction of the carrying values of deferred tax assets by a valuation allowance is required if, based on all available evidence, it is more likely than not that such assets will not be realized. The need to establish valuation allowances for deferred tax assets is assessed at each reporting date. In assessing the requirement for, and amount of, a valuation allowance in accordance with the more-likely-than-not standard, we give appropriate consideration to all positive and negative evidence related to the realization of the deferred tax assets. This assessment considers, among other matters, the nature, frequency and severity of current and cumulative losses, forecasts of future profitability, the duration of statutory carryforward periods, our experience with operating loss and tax credit carryforwards not expiring unused and tax planning strategies. A history of cumulative losses for a certain threshold period is a significant form of negative evidence used in the assessment, and we are required to have a policy regarding the duration of the threshold period. We believe the historical cyclical nature of our operations show economic cycles ranging from 7 to 10 years with demand troughs historically showing recovery over four years . Accordingly, we have a policy of four years as our threshold period for cumulative losses.
Inventory Valuation	Inventory Valuation All of our inventories are stated at the lower of cost or net realizable value and are valued under the average cost method. Our inventories include materials, labor and applicable factory overhead costs. Depreciation associated with manufacturing assets is excluded from inventory cost but is included in cost of products sold.
Earnings per Share	Earnings per Share Basic earnings per share is based on the weighted average number of common shares outstanding. Diluted earnings per share is based on the weighted average number of common shares outstanding plus the dilutive effect, if any, of market share units, or MSUs, restricted stock units, or RSUs, performance shares, stock options and the deferred shares associated with our deferred compensation program for non-employee directors.
Business Combinations	Business Combinations Business combinations are accounted for using the acquisition method of accounting. The purchase price of the acquisition is allocated to the tangible and intangible assets acquired and liabilities assumed based on their fair values at the acquisition date. The calculation of fair value of the identified intangible assets are determined using cash flow models following the income approach or a discounted market-based methodology approach. Significant inputs include projected revenues, gross margins, operating expenses, estimated attrition rate and discount rates. The excess of fair value of the purchase price over the fair values of the tangible and identifiable intangible assets acquired and liabilities assumed is recorded as goodwill. During the measurement period, which may be up to one year from the acquisition date, we may record adjustments to the net assets with the corresponding offset to goodwill. The results of operations of the acquired business are included in our consolidated results of operations beginning on the date of the acquisition. Acquisition-related expenses, including legal costs, due diligence costs and business valuation costs, are expensed as incurred.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include highly liquid investments, primarily money market funds, with maturities of three months or less at the time of purchase.
Marketable Securities	Marketable Securities Marketable securities are classified as available-for-sale securities and reported at fair value, with unrealized gains and losses excluded from earnings and reported in accumulated other comprehensive income (loss), or AOCI. If it is deemed that marketable securities have unrealized losses that are other than temporary, these losses will be recorded in earnings immediately. Situations in which losses may be considered other than temporary include when we have decided to sell a security or when it is more likely than not that we will be required to sell the security before we recover its amortized cost basis. Cost basis for securities sold are determined on a first-in-first-out basis.
Receivables	Receivables Receivables are recorded at net realizable value, which includes allowances for cash discounts and doubtful accounts. We review the collectability of receivables on an ongoing basis and reserve for receivables determined to be uncollectible. This determination is based on the delinquency of the account, the financial condition of the customer and our collection experience. We include short-term financing receivables in "Receivables" and long-term financing and loan receivables in "Other assets" on our consolidated balance sheets. Financing and loan receivables are recorded at net realizable value which includes an allowance for credit losses. We review the collectability of financing and loan receivables on an ongoing basis and reserve for financing and loan receivables determined to be uncollectible. This determination is based on the delinquency of the account and the financial condition of the other party.
Investments in Unconsolidated Joint Ventures	Investments in Unconsolidated Joint Ventures The equity method of accounting is used for investments in joint ventures that we do not consolidate, but over which we have the ability to exercise significant influence. These investments are initially recorded at cost and subsequently adjusted for our share of the net income or loss and cash contributions and distributions to or from these entities. If the underlying net assets in our investments are denominated in a foreign currency, we adjust the value of our investment for translation gains or losses with a corresponding adjustment to our AOCI. We are required to pay Boral, our UBBP joint venture partner, an earnout of $50 million in 2019 if certain financial metrics are met. At least quarterly, we review the probability of this earnout payment to Boral. At December 31, 2017 , we concluded that it is currently not probable that the earnout target will be achieved. If our conclusion on the probability of achievement were to change, we will record a liability representing the present value of the second earnout payment with a corresponding increase to our investment. Losses in the value of an equity method investment that are other than temporary are recognized when the current fair value of the investment is less than its carrying value. We review our investments in equity method investments for impairment whenever factors indicate an other than temporary loss in value. If we conclude a loss in value is other than temporary, an impairment charge is recognized for the difference between the investment’s carrying value and its estimated fair value.
Property, Plant and Equipment	Facility start-up costs that cannot be capitalized are expensed as incurred and recorded in cost of products sold. Property, plant and equipment is reviewed for impairment when indicators of a potential impairment are present by comparing the carrying values of the assets with their estimated future undiscounted cash flows. If we determine an impairment exists, the asset is written down to fair value. Property, Plant and Equipment Property, plant and equipment is recorded at cost. We record depreciation of property, plant and equipment on a straight-line basis over the expected useful lives of the assets. We have determined estimated useful lives to be 50 years for buildings and improvements, a range of 10 to 25 years for machinery and equipment, and a range of 5 to 7 years for computer software and systems development costs. Leasehold improvements are capitalized and amortized over the shorter of the remaining lease term or remaining economic useful life. We compute depletion on a basis calculated to spread the cost of gypsum and other applicable resources over the estimated quantities of material recoverable. We capitalize interest during the active construction period of major capital projects. Capitalized interest is added to the cost of the underlying assets and is depreciated over the useful lives of those assets.
Intangible Assets, Indefinite Lived	Intangible Assets We perform impairment tests for intangible assets with indefinite useful lives once a year, or more frequently if events occur or circumstances change that would more likely than not reduce the fair value of an intangible asset below its carrying value. The impairment test for assets with indefinite lives consists of a comparison of the fair value of the asset with its carrying value. If the carrying value of an intangible asset exceeds its fair value, an impairment loss is recognized in an amount equal to that excess. Intangible assets determined to have indefinite useful lives, primarily composed of trade names, are not amortized. An income approach is used for valuing trade names. Assumptions used in the income approach include projected revenues and assumed royalty, long-term growth and discount rates.
Intangible Assets, Definite Lived	We perform impairment tests on definite lived intangible assets upon identification of events or circumstances that may indicate the carrying value of the assets might be unrecoverable by comparing their undiscounted cash flows with their carrying value. If we determine impairment exists, the assets are written down to estimated fair value.
Goodwill	Goodwill We perform an impairment test on goodwill as of October 1, or more frequently if events occur or circumstances change that would more likely than not reduce the fair value below its carrying value. In testing goodwill for impairment, we have the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the estimated fair value of a reporting unit is less than its carrying value. If we elect to perform a qualitative assessment and determine that an impairment is more likely than not, we are then required to perform a quantitative impairment test, otherwise no further analysis is required. We also may elect not to perform the qualitative assessment and, instead, proceed directly to the quantitative impairment test. We perform a quantitative analysis which involves comparing the current fair value of each reporting unit to its carrying value, including goodwill. If the carrying value of a reporting unit exceeds its fair value, we recognize an impairment loss equal to the difference between the carrying value and the estimated fair value of the reporting unit.
Asset Retirement Obligations	Asset Retirement Obligations Our asset retirement obligations include reclamation requirements as regulated by government authorities related principally to assets such as our mines, quarries, landfills, ponds and wells. The accounting for asset retirement obligations requires estimates by management about the timing of asset retirements, the cost of retirement obligations, discount and inflation rates used in determining fair values and the methods of remediation associated with our asset retirement obligations. We generally use assumptions and estimates that reflect the most likely remediation method on a site-by-site basis. Our estimated liability for asset retirement obligations is revised annually, and whenever events or changes in circumstances indicate that a revision to the estimate is necessary. In instances where a decrease in the asset retirement obligation is in excess of the related remaining net book value of the asset retirement costs, the excess is recorded to the consolidated statement of income as a reduction in "Cost of products sold." Asset retirement obligations are included in "Other liabilities" on the consolidated balance sheets.
Share-Based Compensation	Share-Based Compensation We award share-based compensation to employees in the form of MSUs, performance shares and RSUs and to non-employee directors in the form of shares of our common stock. All grants under share-based payment programs are accounted for at fair value at the date of grant. We recognize expense on all share-based awards to employees expected to vest over the service period, which is the shorter of the period until the employees’ retirement eligibility dates or the service period of the award. We record forfeitures as they occur.
Derivative Instruments	Derivative Instruments We use derivative instruments to manage selected commodity price and foreign currency exposures. We do not use derivative instruments for speculative trading purposes, and we typically do not hedge beyond six years . All derivative instruments are recorded on the balance sheet at fair value. For derivatives designated as cash flow hedges, the effective portion of changes in the fair value of the derivative is recorded to AOCI, and is reclassified to earnings when the underlying forecasted transaction affects earnings. The ineffective portion of changes in the fair value of the derivative is reported in cost of products sold in the current period. For contracts designated as cash flow hedges, we reassess the probability of the underlying forecasted transactions occurring on a quarterly basis. For derivatives designated as net investment hedges, we record changes in fair value to AOCI. For derivatives not designated as hedging instruments, all changes in fair value are recorded to earnings in the current period. Cash flows from derivative instruments are included in operating activities in our consolidated statements of cash flows. We use swaps to hedge a significant portion of our anticipated purchases of natural gas to be used in our manufacturing operations. Generally, we hedge the cost of a majority of our anticipated purchases of natural gas over the next 12 months . However, we review our positions regularly and make adjustments as market conditions warrant. The majority of contracts currently in place are designated as cash flow hedges and the remainder are not designated as hedging instruments. We have operations outside of the United States and use forward contracts to hedge the risk of changes in cash flows resulting from selected forecasted intercompany and third-party sales or purchases, as well as intercompany loans, denominated in non-U.S. currencies, or to hedge the risk of selected changes in our net investment in foreign subsidiaries. These contracts are designated as either cash flow or net investment hedges or are not designated as hedging instruments.
Foreign Currency Translation	Foreign Currency Translation We translate foreign-currency-denominated assets and liabilities into U.S. Dollars at the exchange rates existing as of the respective balance sheet dates. We translate income and expense items at the average exchange rates during the respective periods. We record translation adjustments resulting from fluctuations in exchange rates to AOCI on our consolidated balance sheets. We record transaction gains and losses to earnings.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities are required to be recorded at fair value. The estimated fair values of those assets and liabilities have been determined using market information and valuation methodologies. Changes in assumptions or estimation methods could affect the fair value estimates. However, we do not believe any such changes would have a material impact on our financial condition, results of operations or cash flows. There are three levels of inputs that may be used to measure fair value: • Level 1 – Quoted prices for identical assets and liabilities in active markets; • Level 2 – Quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets; and • Level 3 – Valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. Certain assets and liabilities are measured at fair value on a nonrecurring basis rather than on an ongoing basis, but are subject to fair value adjustments in certain circumstances, such as an acquisition, when evidence of impairment or when a new liability is being established that requires fair value measurement.

Significant Accounting Polici31

Significant Accounting Policies - Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Schedule of ant-dilutive securities excluded from computation of diluted earnings (loss) per share	The shares that were not included in the computation of diluted earnings per share for those periods because their inclusion would be anti-dilutive were as follows: (millions, common shares) 2017 2016 2015 Stock options, RSUs, MSUs and performance shares 0.7 1.5 1.9 Deferred shares associated with a deferred compensation program for non-employee directors 0.2 0.2 —

Recent Accounting Pronounceme32

Recent Accounting Pronouncements - Recent Accounting Pronouncements (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Changes in presentation of net benefit costs	Select line items from our consolidated statements of income for the years ended December 31, 2017 and 2016 which reflect the changes in presentation of net benefit costs are as follows: (millions) Year ended December 31, 2017 Year ended December 31, 2016 After Adoption As Reported After Adoption As Reported Gross profit $ 656 $ 665 $ 700 $ 705 Operating profit 353 367 396 394 Other net periodic postretirement benefit (costs) 14 — (2 ) — Net income 88 88 510 510

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations And Discontinued Operations and Disposal Groups [Abstract]
Summarized financial information of discontinued operations	The summarized financial information related to L&W that has been excluded from continuing operations and reported as a discontinued operation is as follows: (millions) For the year ended December 31, 2016(a) 2015 Net sales $ 1,252 $ 1,428 Cost of products sold 1,196 1,387 Gross profit 56 41 Selling and administrative expenses (b) 22 15 Operating profit 34 26 Income tax expense 12 11 Net income from discontinued operations (c) $ 22 $ 15 Gain on sale of discontinued operations $ 279 $ — (a) Operating results for 2016 are presented for the ten months ended October 31, 2016. (b) The ten month period ended October 31, 2016 included transaction costs of $8 million . (c) The year ended December 31, 2016 included $2 million of net loss from discontinued operations from our European business, which were sold in 2012.

Equity Method Investments (Tabl

Equity Method Investments (Tables)	12 Months Ended
	Dec. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Schedule of equity method investments	Equity method investments were as follows: December 31, 2017 December 31, 2016 (millions) Carrying Value Ownership Percentage Carrying Value Ownership Percentage USG Boral Building Products $ 679 50% $ 621 50% Other equity method investments 7 33% - 50% $ 7 33% - 50% Total equity method investments $ 686 $ 628
Schedule of translation gains or losses recorded in other comprehensive income	Translation gains and losses recorded in other comprehensive income were as follows: (millions) 2017 2016 2015 Translation gain (loss) $ 40 $ (30 ) $ (23 )
Statement of operations from equity method investments	Summarized financial information for our equity method investments is as follows: Statements of Income For the year ended December 31, (millions) 2017 2016 2015 USG Boral Building Products: Net sales $ 1,200 $ 1,052 $ 1,003 Gross profit (a) 369 337 278 Operating profit 160 133 124 Net income before taxes 174 142 132 Net income 121 95 101 Net income attributable to USG Boral Building Products 117 99 96 USG share of income from USG Boral Building Products (b) 59 49 48 Other equity method investments (c) : USG share of income from other investments accounted for using the equity method — — 2 Total income from equity method investments 59 49 50 (a) Year ended December 31, 2016 includes long-lived asset impairment charges of $8 million for China and of $14 million for Oman. (b) Year ended December 31, 2016 includes long-lived asset impairment charges of $4 million for China and of $4 million for Oman. (c) Amounts represent our share of income or loss from all equity method investments, other than UBBP.
Balance Sheet from equity method investments	Balance Sheets (millions) December 31, 2017 December 31, 2016 USG Boral Building Products: Current assets $ 438 $ 389 Non-current assets 981 903 Current liabilities (a) 255 211 Long-term debt 10 37 Other non-current liabilities 12 17 Shareholders' equity (b) 1,142 1,027 (a) Includes the current portion of long-term debt of $16 million and $15 million as of December 31, 2017 and 2016 , respectively. (b) Shareholders' equity includes $66 million and $50 million related to non-controlling interests as of December 31, 2017 and 2016 , respectivel y.

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Schedule of investments in marketable securities	Our investments in marketable securities as of December 31, 2017 and 2016 consisted of the following: 2017 2016 (millions) Amortized Cost Fair Value Amortized Cost Fair Value Corporate debt securities $ 68 $ 68 $ 69 $ 69 U.S. government and agency debt securities 6 6 14 14 Asset-backed debt securities 11 11 2 2 Certificates of deposit 13 13 6 6 Municipal debt securities 1 1 — — Total marketable securities $ 99 $ 99 $ 91 $ 91
Schedule of contractual maturities of marketable securities	Contractual maturities of marketable securities as of December 31, 2017 were as follows: (millions) Amortized Cost Fair Value Due in 1 year or less $ 62 $ 62 Due in 1-5 years 37 37 Total marketable securities $ 99 $ 99

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of total debt	Total debt as of December 31 consisted of the following: (millions) 2017 2016 4.875% senior notes due 2027 $ 500 $ — 5.5% senior notes due 2025 350 350 7.75% senior notes due 2018 — 500 Industrial revenue bonds (due 2028 through 2034) 239 239 Total $ 1,089 $ 1,089 Less: Unamortized debt issuance costs 11 6 Total $ 1,078 $ 1,083 Interest rate 5.5% 4.875% Principal net of discount (in millions) (a) $350 $500 Maturity March 1, 2025 June 1, 2027 Call date (b) March 1, 2020 June 1, 2022 Mandatory redemption offer at 101% plus accrued and unpaid interest in the event of a change in control at 101% plus accrued and unpaid interest in the event of a change in control (a) Principal amounts exclude unamortized debt issuance costs. (b) Callable at any time, in whole or in part, prior to the call date at a redemption price equal to 100% of the principal plus a premium (as outlined in the respective indentures), plus any accrued and unpaid interest on the principal amount being called. Callable after the call date at stated redemption prices (as outlined in the applicable indenture), plus any accrued and unpaid interest on the principal amount being called.
Schedule of fair value of debt	(millions) December 31, 2017 December 31, 2016 Fair value of debt $ 1,134 $ 1,129 Accrued interest 12 31
Schedule of amounts of total debt outstanding maturing in each of next five years and beyond	As of December 31, 2017 , the amounts of total debt outstanding maturing in each of the next five years and beyond were as follows: (millions) 2018 through 2022 After 2022 Debt maturities (principal amounts) $ — $ 1,089

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of derivative Instruments used to manage commodity price and foreign currency exposure	We use derivative instruments to manage selected commodity price and foreign currency exposures as described below. Derivative Instruments Type Hedged Item Aggregate Notional Amount Contracts Maturing Through Commodity Natural gas swaps Purchases of natural gas 38 million mmBTUs* December 31, 2022 Foreign Exchange Forward contracts Purchases of products and services denominated in a foreign currency $95 million December 31, 2018 * - millions of British Thermal Units
Schedule of pretax effects of derivative instruments	The following are the pre-tax effects of derivative instruments on our consolidated statements of income and our consolidated statements of comprehensive income for the years ended December 31, 2017 , 2016 and 2015 : Amount of Gain or (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives (Effective Portion) Location of Gain or (Loss) Reclassified from AOCI into Income (Effective Portion) Amount of Gain or (Loss) Reclassified from AOCI into Income (Effective Portion) (millions) 2017 2016 2015 2017 2016 2015 Derivatives Designated as Hedging Instruments Commodity contracts $ (19 ) $ 6 $ (14 ) Cost of products sold $ (4 ) $ (15 ) $ (15 ) Foreign exchange contracts (5 ) (3 ) 12 Cost of products sold (2 ) 5 7 Foreign exchange contracts — — 1 Income and gain from the sale of equity method investment to related party — — 1 Total $ (24 ) $ 3 $ (1 ) $ (6 ) $ (10 ) $ (7 ) Location of Gain or (Loss) Recognized in Income on Derivatives Amount of Gain or (Loss) Recognized in Income on Derivatives (millions) 2017 2016 2015 Derivatives Not Designated as Hedging Instruments Commodity contracts Cost of products sold $ (1 ) $ 1 $ (3 ) Foreign exchange contracts Other (income) expense, net — — 2 Total $ (1 ) $ 1 $ (1 )
Schedule of fair values of derivative instruments	The fair values of derivative instruments on the consolidated balance sheets are as follows: Balance Sheet Location Fair Value Balance Sheet Location Fair Value (millions) 12/31/17 12/31/16 12/31/17 12/31/16 Derivatives Designated as Hedging Instruments Commodity contracts Other current assets $ 1 $ 8 Accrued expenses $ 6 $ 4 Commodity contracts Other assets 1 3 Other liabilities 8 5 Foreign exchange contracts Other current assets — 1 Accrued expenses 3 1 Total derivatives in hedging relationships $ 2 $ 12 $ 17 $ 10 Derivatives Not Designated as Hedging Instruments Commodity contracts Other current assets $ — $ 1 Accrued expenses $ — $ — Commodity contracts Other assets — — Other liabilities — — Total derivatives not designated as hedging instruments $ — $ 1 $ — $ — Total derivatives Total assets $ 2 $ 13 Total liabilities $ 17 $ 10

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of assets and liabilities measured at fair value on a recurring basis	Our assets and liabilities measured at fair value on a recurring basis were as follows: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (millions) 12/31/17 12/31/16 12/31/17 12/31/16 12/31/17 12/31/16 12/31/17 12/31/16 Cash equivalents $ 124 $ 38 $ 24 $ 34 $ — $ — $ 148 $ 72 Equity mutual funds 6 5 — — — — 6 5 Marketable securities: Corporate debt securities — — 68 69 — — 68 69 U.S. government and agency debt securities — — 6 14 — — 6 14 Asset-backed debt securities — — 11 2 — — 11 2 Certificates of deposit — — 13 6 — — 13 6 Municipal debt securities — — 1 — — — 1 — Derivative assets — — 2 13 — — 2 13 Derivative liabilities — — (17 ) (10 ) — — (17 ) (10 )

Employee Retirement Plans (Tabl

Employee Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Schedule of Net Benefit Costs	The location of the settlement expense within our consolidated statements of income and the group of employees for which it is related is as follows: (millions) 2017 2016 Cost of products sold USG retirees or terminated vested employees $ 10 $ 7 Selling and administrative expenses USG retirees or terminated vested employees 2 4 (Loss) income from discontinued operations Terminated employees of L&W 13 — Gain on sale of discontinued operations Terminated employees of L&W — 15 Total $ 25 $ 26
Summary of components of net pension and postretirement benefits costs	The components of net pension and postretirement benefit costs are summarized in the following table: (millions) 2017 2016 2015 Pension Benefits: Service cost of benefits earned $ 44 $ 45 $ 49 Interest cost on projected benefit obligation 61 66 66 Expected return on plan assets (93 ) (89 ) (83 ) Settlement (a) 25 35 1 Net amortization 22 22 39 Net pension cost (b) $ 59 $ 79 $ 72 Postretirement Benefits: Service cost of benefits earned $ 2 $ 2 $ 2 Interest cost on projected benefit obligation 5 6 6 Curtailment — (20 ) — Net amortization (23 ) (27 ) (31 ) Net postretirement benefit (c) $ (16 ) $ (39 ) $ (23 ) (a) In 2016, $26 million of the settlement charge reflects the increase in lump sum benefits paid largely driven by the sale of L&W and $9 million reflected payments from our supplemental plan. (b) Net pension costs, excluding settlement costs, includes amounts allocated to (loss) income from discontinued operations for L&W totaling a benefit of $1 million for 2017 and expense of $7 million for 2016 and $12 million for 2015. (c) Net postretirement benefit, excluding curtailment gain, includes a net benefit allocated to (loss) income from discontinued operations for L&W of $1 million for 2017, $3 million for 2016 and $3 million for 2015.
Schedule of accumulated benefit obligation for the defined benefit pension plans	As of December 31, (millions) 2017 2016 Selected information for pension plans with accumulated benefit obligations in excess of plan assets: Accumulated benefit obligation $ (35 ) $ (39 ) Fair value of plan assets 3 2 Selected information for pension plans with benefit obligations in excess of plan assets: Benefit obligation $ (1,769 ) $ (1,384 ) Fair value of plan assets 1,576 1,205
Summary of projected benefit obligations, plan assets and funded status	The following table summarizes projected benefit obligations, plan assets and funded status as of December 31: Pension Postretirement (millions) 2017 2016 2017 2016 Change in Benefit Obligation: Benefit obligation as of January 1 $ 1,610 $ 1,564 $ 135 $ 144 Service cost 44 45 2 2 Interest cost 61 66 5 6 Settlements (121 ) (123 ) — — Curtailments — (37 ) — (7 ) Participant contributions 9 11 — — Benefits paid (51 ) (33 ) (6 ) (7 ) Actuarial (gain) loss 202 112 10 (5 ) Foreign currency translation 16 5 4 2 Benefit obligation as of December 31 $ 1,770 $ 1,610 $ 150 $ 135 Change in Plan Assets: Fair value as of January 1 $ 1,435 $ 1,301 $ — $ — Actual return on plan assets 217 107 — — Employer contributions 71 167 6 7 Participant contributions 9 11 — — Benefits paid (51 ) (33 ) (6 ) (7 ) Settlements (121 ) (123 ) — — Foreign currency translation 17 5 — — Fair value as of December 31 $ 1,577 $ 1,435 $ — $ — Funded status $ (193 ) $ (175 ) $ (150 ) $ (135 ) Components on the Consolidated Balance Sheets: Noncurrent assets $ — $ 4 $ — $ — Current liabilities (8 ) (16 ) (9 ) (8 ) Noncurrent liabilities (185 ) (163 ) (141 ) (127 ) Net liability as of December 31 $ (193 ) $ (175 ) $ (150 ) $ (135 ) Pretax Components in AOCI: Net actuarial loss $ 421 $ 388 $ 11 $ — Prior service credit — (1 ) (42 ) (65 ) Total as of December 31 $ 421 $ 387 $ (31 ) $ (65 )
Schedule of assumptions used in the accounting for the plans	The following tables reflect the assumptions used in the accounting for our plans: Pension Postretirement 2017 2016 2017 2016 Weighted average assumptions used to determine benefit obligations as of December 31: Discount rate 3.55 % 4.02 % 3.42 % 3.90 % Compensation increase rate 3.54 % 3.55 % N/A N/A Weighted average assumptions used to determine net cost for years ended December 31: Discount rate 4.02 % 4.43 % 3.90 % 4.24 % Expected return on plan assets 6.54 % 6.66 % N/A N/A Compensation increase rate 3.55 % 3.55 % N/A N/A
Schedule of effect of one percentage point change in the assumed health care cost trend rates	A one percentage point change in the assumed health care cost trend rates would have the following effects on our Canadian plans: (millions) One-Percentage- Point Increase One-Percentage- Point Decrease Effect on total service and interest cost $ 1 $ — Effect on postretirement benefit obligation 13 (10 )
Schedule of aggregate target asset allocation on a weighted average basis for all the plans and the acceptable ranges around the targets	The following table shows the aggregate target asset allocation on a weighted average basis for all the plans and the acceptable ranges around the targets as of December 31, 2017 . Investment Policy Asset Categories Asset Category Description Target Range Equity Institutional commingled/pooled equity funds, equity mutual funds and direct holdings of the common stock of U.S. and non-U.S. companies; equity funds and direct holdings are invested in companies with a range of market capitalizations 36% 32%-40% Fixed income U.S. Treasury securities, non-U.S. government debt securities such as Canadian federal bonds, corporate bonds of companies from diversified industries and mortgage-backed securities 54% 45%-63% Limited partnerships Investments in funds that follow any of several different strategies, including investing in distressed debt, energy development, infrastructure, and hedge funds. These investments use strategies with returns normally expected to have a reduced correlation to the return of equities as compared to other asset classes and often provide a current income component that is a meaningful portion of the investment’s total return. 5% 1%-8% Other real assets Primarily investments in large core, private real estate funds that directly own a diverse portfolio of properties located in the United States. It also includes an allocation to funds investing in equities of real estate and infrastructure companies 5% 2%-9% Cash equivalents and short-term investments Primarily held in short-term investment funds or registered money market funds with daily liquidity —% 0%-5% Total 100%
Schedule of fair values by hierarchy of inputs	The fair values by hierarchy of inputs as of December 31 were as follows: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total (millions) 2017 2016 2017 2016 2017 2016 2017 2016 Asset Categories: Equity: Common and preferred stock $ 92 $ 66 $ — $ — $ — $ — $ 92 $ 66 Commingled/pooled/mutual funds (a) — — 553 490 — — 553 490 Total equity 92 66 553 490 — — 645 556 Fixed income: U.S. government and agency debt securities — — 8 194 — — 8 194 Non-U.S. government and agency debt securities — — 68 54 — — 68 54 Investment-grade debt securities — — 334 197 — — 334 197 High-yield debt securities — — 42 53 — — 42 53 Commingled/pooled funds (a) — — 305 165 — — 305 165 Mortgaged backed securities — — 1 3 — — 1 3 Other — — 13 10 1 1 14 11 Total fixed income — — 771 676 1 1 772 677 Limited partnerships — — — — 91 103 91 103 Other real estate assets — — 18 16 39 38 57 54 Cash equivalents and short-term investments — — 14 11 — — 14 11 Total $ 92 $ 66 $ 1,356 $ 1,193 $ 131 $ 142 $ 1,579 $ 1,401 Cash on hand — — Receivables 2 35 Accounts payable (4 ) (1 ) Total $ 1,577 $ 1,435 (a) Certain investments in commingled/pooled equity funds have been classified as Level 2 because observable quoted prices for these institutional funds are not available.
Reconciliation of the change in the fair value measurement of the defined benefit plans’ consolidated assets	A reconciliation of the change in the fair value measurement of the defined benefit plans’ consolidated assets using significant unobservable inputs (Level 3) between January 1, 2016 and December 31, 2017 is as follows: (millions) Fixed Income Other Real Estate Assets Limited Partnerships Total Balance as of January 1, 2016 $ 1 $ 37 $ 106 $ 144 Realized losses — 1 5 6 Unrealized gains — 2 (3 ) (1 ) Purchases, sales and settlements: Purchases — — 1 1 Sales — (2 ) (6 ) (8 ) Settlements — — — — Net transfers into (out of) Level 3 — — — — Balance as of December 31, 2016 $ 1 $ 38 $ 103 $ 142 Realized gains — 1 15 16 Unrealized gains (losses) — 2 (1 ) 1 Purchases, sales and settlements: Purchases — — 9 9 Sales — (2 ) (35 ) (37 ) Settlements — — — — Net transfers into (out of) Level 3 — — — — Balance as of December 31, 2017 $ 1 $ 39 $ 91 $ 131
Schedule of expected benefit payments	Total benefit payments we expect to make to participants, which include payments funded from USG’s assets as well as payments from our pension plans' assets, are as follows (in millions): Years ended December 31 Pension Benefits Postretirement Benefits 2018 $ 120 $ 9 2019 125 9 2020 137 8 2021 134 8 2022 141 8 2023 - 2027 634 42

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted average grant date fair values of MSUs	We granted MSUs with the following weighted average grant date fair values: 2017 2016 2015 Weighted average grant date fair values $ 35.79 $ 19.59 $ 30.06
Schedule of MSUs valuation assumptions	We estimated the fair value of each MSU granted on the date of grant using a Monte Carlo simulation that used the assumptions noted in the following table. Volatility was based on stock price history immediately prior to grant for a period commensurate with the expected term. The risk-free rate was based on zero-coupon U.S. government issues at the time of grant. The expected term represents the period from the valuation date to the end of the performance period. Assumptions: 2017 2016 2015 Expected volatility 32.10 % 34.02 % 42.70 % Risk-free rate 1.39 % 0.86 % 1.09 % Expected term (in years) 2.96 2.95 2.95 Expected dividends — — —
Schedule of nonvested MSUs outstanding and activity	Nonvested MSUs outstanding as of December 31, 2017 and MSU activity during 2017 were as follows: Number of MSUs (000) Weighted Average Grant Date Fair Value Nonvested at January 1, 2017 1,157 $ 23.39 Granted 371 35.79 Vested (417 ) 30.06 Forfeited (14 ) 26.20 Nonvested at December 31, 2017 1,097 25.01
Weighted average grant date fair values of performance shares	We granted performance shares with the following weighted average grant date fair values: 2017 2016 2015 Weighted average grant date fair values $ 39.42 $ 21.10 $ 30.63
Schedule of performance based units valuation assumptions	We estimated the fair value of each performance share granted on the date of grant using a Monte Carlo simulation that uses the assumptions noted in the following table. Volatility was based on stock price history immediately prior to grant for a period commensurate with the expected term. The risk-free rate was based on zero-coupon U.S. government issues at the time of grant. The expected term represents the period from the grant date to the end of the three -year performance period. Assumptions: 2017 2016 2015 Expected volatility 32.10 % 34.02 % 42.70 % Risk-free rate 1.39 % 0.86 % 1.09 % Expected term (in years) 2.96 2.95 2.95 Expected dividends — — —
Summary of nonvested performance share outstanding and performance share activity	Nonvested performance shares outstanding as of December 31, 2017 and performance share activity during 2017 were as follows: Number of Performance Shares (000) Weighted Average Grant Date Fair Value Nonvested at January 1, 2017 246 $ 24.98 Granted 113 39.42 Vested (99 ) 30.63 Forfeited (4 ) 26.75 Nonvested at December 31, 2017 256 29.14
Weighted average grant date fair values of RSUs	We granted RSUs with the following weighted average grant date fair values: 2017 2016 2015 Weighted average grant date fair values $ 31.57 $ 23.94 $ 28.56
Summary of nonvested RSUs outstanding and activity	RSUs outstanding as of December 31, 2017 and RSU activity during the year then ended were as follows: Number of RSUs (000) Weighted Average Grant Date Fair Value Nonvested at January 1, 2017 228 $ 27.31 Granted 133 31.57 Vested (54 ) 31.38 Forfeited (3 ) 29.83 Nonvested at December 31, 2017 304 14.67
Summary of stock options outstanding and stock option activity	A summary of stock options outstanding as of December 31, 2017 and of stock option activity during the year then ended is presented below: Number of Options (000) Weighted Average Exercise Price Weighted Average Remaining Contractual Term (years) Aggregate Intrinsic Value (millions) Outstanding at January 1, 2017 2,174 $ 22.55 2.78 $ 22 Exercised (590 ) 23.88 Canceled (323 ) 46.80 Outstanding at December 31, 2017 1,261 $ 15.72 2.48 $ 28 Exercisable at December 31, 2017 1,261 $ 15.72 2.48 $ 28 Vested at December 31, 2017 1,261 $ 15.72 2.48 $ 28 (millions) 2017 2016 2015 Intrinsic value of stock options exercised $ 7 $ 4 $ 6 Cash received from stock options exercised $ 14 $ 4 $ 6 Fair value of stock options vested $ — $ 1 $ 1

Supplemental Balance Sheet In41

Supplemental Balance Sheet Information (Tables)	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of inventories	Inventories as of December 31 consisted of the following: (millions) 2017 2016 Finished goods $ 140 $ 132 Work in progress 39 37 Raw materials 73 67 Total $ 252 $ 236
Schedule of property, plant and equipment	Property, plant and equipment as of December 31 consisted of the following: (millions) 2017 2016 Land and mineral deposits $ 120 $ 116 Buildings and improvements 1,100 1,078 Machinery and equipment 2,595 2,473 3,815 3,667 Reserves for depreciation and depletion (2,053 ) (1,960 ) Total $ 1,762 $ 1,707 Annual depreciation and depletion expense $ 129 $ 129
Schedule of accrued expenses	Accrued expenses as of December 31 consisted of the following: (millions) 2017 2016 Self-insurance reserves $ 12 $ 12 Employee compensation 17 35 Interest 12 31 Derivatives 9 5 Pension and other postretirement benefits 17 24 Environmental 17 18 Other 51 50 Total $ 135 $ 175
Schedule of change in asset retirement obligation	Changes in our liability for asset retirement obligations consisted of the following: (millions) 2017 2016 Balance as of January 1 $ 113 $ 119 Accretion expense 7 7 Liabilities incurred 3 2 Changes in estimated cash flows (a) (4 ) (12 ) Liabilities settled (3 ) (4 ) Foreign currency translation 2 1 Balance as of December 31 $ 118 $ 113 (a) Changes in estimated cash flows for the year ended December 31, 2016 includes a $8 million reduction related to one of our quarries.
Schedule of changes in balances of each component of accumulated other comprehensive income (loss)	Changes in the balances of each component of accumulated other comprehensive income (loss), or AOCI, are summarized in the following table: (millions) Derivatives Pension and Other Postretirement Benefit Plans Foreign Total AOCI Balance as of January 1, 2015 $ 16 $ (302 ) $ (52 ) $ (338 ) Other comprehensive income (loss) before reclassifications, net of tax (5 ) 74 (67 ) 2 Less: Amounts reclassified from AOCI, net of tax (9 ) (7 ) (6 ) (22 ) Other comprehensive income (loss), net of tax 4 81 (61 ) 24 Balance as of December 31, 2015 $ 20 $ (221 ) $ (113 ) $ (314 ) Other comprehensive income (loss) before reclassifications, net of tax 1 (34 ) (53 ) (86 ) Less: Amounts reclassified from AOCI, net of tax (6 ) (9 ) — (15 ) Other comprehensive income (loss), net of tax 7 (25 ) (53 ) (71 ) Balance as of December 31, 2016 $ 27 $ (246 ) $ (166 ) $ (385 ) Other comprehensive income (loss) before reclassifications, net of tax (14 ) (65 ) 58 (21 ) Less: Amounts reclassified from AOCI, net of tax (3 ) (14 ) — (17 ) Other comprehensive income (loss), net of tax (11 ) (51 ) 58 (4 ) Balance as of December 31, 2017 $ 16 $ (297 ) $ (108 ) $ (389 )
Schedule of amounts reclassified from accumulated other comprehensive income, net of tax	Amounts reclassified from AOCI, net of tax, for the years ended December 31, 2017 , 2016 and 2015 were as follows: (millions) 2017 2016 2015 Derivatives Net reclassification from AOCI for cash flow hedges included in cost of products sold $ (6 ) $ (10 ) $ (8 ) Net reclassification from AOCI for cash flow hedges included in income and gain from the sale of equity method investment to related party — — 1 Less: Income tax (benefit) expense on reclassification from AOCI included in income tax expense (3 ) (4 ) 2 Net amount reclassified from AOCI $ (3 ) $ (6 ) $ (9 ) Pension and postretirement benefits Net reclassification from AOCI for amortization of prior service (benefit) cost included in cost of products sold $ (8 ) $ (1 ) $ 1 Net reclassification from AOCI for amortization of prior service benefit included in selling and administrative expenses (5 ) (12 ) (5 ) Net reclassification from AOCI for amortization of prior service benefit included in (loss) income from and gain on sale of discontinued operations (11 ) (3 ) (4 ) Less: Income tax expense on reclassification from AOCI included in income tax expense (10 ) (7 ) (1 ) Net amount reclassified from AOCI $ (14 ) $ (9 ) $ (7 ) Foreign Currency Translation Net reclassification from AOCI for translation loss realized upon the sale of foreign entities $ — $ — $ (6 ) Net amount reclassified from AOCI $ — $ — $ (6 )

Segments (Tables)

Segments (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Schedule of reportable segment results	The results of our five reportable segments are as follows: CONSOLIDATED SEGMENTS For the year ended December 31, (millions) 2017 2016 2015 Net Sales: U.S. Wallboard and Surfaces $ 1,916 $ 1,778 $ 1,720 U.S. Performance Materials 373 357 321 U.S. Ceilings 477 467 464 Canada 405 389 372 Other 245 220 239 Eliminations (212 ) (194 ) (203 ) Total $ 3,204 $ 3,017 $ 2,913 Operating Profit (Loss): U.S. Wallboard and Surfaces $ 314 $ 334 $ 298 U.S. Performance Materials 26 41 31 U.S. Ceilings 95 101 80 Canada 12 26 10 Other 11 (4 ) 30 Corporate (90 ) (104 ) (94 ) Eliminations (1 ) — — Total $ 367 $ 394 $ 355 Depreciation, Depletion and Amortization: U.S. Wallboard and Surfaces $ 91 $ 87 $ 85 U.S. Performance Materials 9 9 8 U.S. Ceilings 15 15 15 Canada 6 6 6 Other 5 7 8 Corporate 6 10 9 Total $ 132 $ 134 $ 131 Capital Expenditures: U.S. Wallboard and Surfaces $ 104 $ 60 $ 73 U.S. Performance Materials 31 11 4 U.S. Ceilings 17 4 3 Canada 10 4 4 Other 5 3 3 Corporate 1 1 — Total $ 168 $ 83 $ 87 As of December 31, Assets: 2017 2016 2015 U.S. Wallboard and Surfaces $ 1,574 $ 1,540 $ 1,590 U.S. Performance Materials 172 154 147 U.S. Ceilings 307 225 267 Canada 134 124 126 Other 144 135 160 Corporate 856 1,080 1,483 Equity method investments 686 628 682 Assets related to discontinued operations — — 357 Eliminations (22 ) (17 ) (76 ) Total $ 3,851 $ 3,869 $ 4,736
Schedule of revenues by product	CONSOLIDATED PRODUCT SALES INFORMATION For the year ended December 31, (millions) 2017 2016 2015 Net Sales: Gypsum $ 2,331 $ 2,169 $ 2,105 Performance Materials 373 357 321 Ceilings 509 500 496 Elimination (9 ) (9 ) (9 ) Total $ 3,204 $ 3,017 $ 2,913
Schedule of geographic information	CONSOLIDATED GEOGRAPHIC INFORMATION For the year ended December 31, (millions) 2017 2016 2015 Net Sales: United States $ 2,787 $ 2,625 $ 2,524 Canada 406 389 379 Other Foreign 204 189 196 Geographic transfers (193 ) (186 ) (186 ) Total $ 3,204 $ 3,017 $ 2,913 Consolidated long-lived assets, consisting of property, plant and equipment, net, by geographic location were as follows: As of December 31, (millions) 2017 2016 2015 Long-Lived Assets: United States $ 1,604 $ 1,563 $ 1,605 Canada 90 80 90 Other Foreign 68 64 76 Total $ 1,762 $ 1,707 $ 1,771
UBBP Reporting	UBBP For the year ended December 31, (millions) 2017 2016 2015 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 As of December 31, 2017 2016 2015 Assets $ 1,419 $ 1,292 $ 1,303 UBBP For the year ended December 31, (millions) 2017 2016 2015 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 As of December 31, 2017 2016 2015 Assets $ 1,419 $ 1,292 $ 1,303 UBBP GEOGRAPHIC INFORMATION For the year ended December 31, (millions) 2017 2016 2015 Net Sales: Australia $ 431 $ 381 $ 345 South Korea 287 223 200 Thailand 150 141 145 China 119 103 120 Other 271 255 234 Geographic Transfers (58 ) (51 ) (41 ) Total $ 1,200 $ 1,052 $ 1,003 Long-lived assets, consisting of property, plant and equipment, net, by geographic location for UBBP were as follows: As of December 31, (millions) 2017 2016 2015 Long-Lived Assets: Australia $ 229 $ 217 $ 216 South Korea 123 107 106 China 101 97 116 Oman 85 86 103 Thailand 86 75 72 Other 86 71 67 Total $ 710 $ 653 $ 680
Schedule of revenue by major customers	Sales to our significant customers were as follows: Significant Customer Segment with Sales to Significant Customer 2017 2016 2015 The Home Depot U.S. Wallboard and Surfaces, U.S. Performance Materials, U.S. Ceilings, and Canada 23 % 23 % 23 % L&W U.S. Wallboard and Surfaces, U.S. Performance Materials and U.S. Ceilings 16 % 19 % 18 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of income from continuing operations before income taxes	Income from continuing operations before income taxes consisted of the following: (millions) 2017 2016 2015 U.S. $ 272 $ 201 $ 152 Foreign 63 73 84 Total $ 335 $ 274 $ 236
Schedule of income tax expense (benefit) on continuing operations	Income tax expense (benefit) on continuing operations consisted of the following: (millions) 2017 2016 2015 Current: Federal $ (21 ) $ — $ — Foreign 2 5 12 State 2 1 1 Total current $ (17 ) $ 6 $ 13 Deferred: Federal $ 243 $ 41 $ (631 ) Foreign — 2 (4 ) State 12 14 (118 ) Total deferred $ 255 $ 57 $ (753 ) Total $ 238 $ 63 $ (740 )
Schedule of differences between actual provisions for income taxes and provisions for income taxes at the U.S. federal statutory rate	For our continuing operations, differences between actual provisions for income taxes and provisions for income taxes at the U.S. federal statutory rate ( 35% ), prior to changes under the 2017 Tax Act, were as follows: (millions) 2017 2016 2015 Taxes on income from continuing operations at U.S. federal statutory rate $ 117 $ 96 $ 82 Foreign earnings subject to different tax rates (a) 3 (3 ) (3 ) State income tax, net of federal benefit 9 10 8 Change in valuation allowance — — (827 ) Income from equity method investments (b) (21 ) (17 ) (16 ) Law changes (c) 145 — — Prior year return adjustments (7 ) — — Benefits from unrecognized tax positions — — (6 ) Foreign tax credits — (21 ) — Tax expense on distribution of foreign earnings — — 20 Other, net (8 ) (2 ) 2 Provision for income tax expense (benefit) $ 238 $ 63 $ (740 ) Effective income tax rate 71.0 % 22.9 % (313.6 )% (a) Foreign earnings subject to different tax rates includes amounts related to impairments and other charges associated with our former shipping operations. (b) Included in income from equity method investments are taxes associated with that income in the respective jurisdictions. These taxes, which are predominately foreign statutory rates, are at rates that are lower than the U.S. federal statutory rate. (c) The impact of the 2017 Tax Act included the transition tax on deferred foreign earnings, net of foreign tax credits, of $9 million , an increase in the valuation allowance related to foreign tax credits of $106 million , an increase in the valuation allowance of our state NOLs due to the change in federal benefit related to those assets of $18 million , anticipated sequestration of our AMT credits of $3 million and the impact of the corporate rate change on deferred tax assets and liabilities of $9 million .
Schedule of components of deferred tax assets and liabilities	Significant components of deferred tax assets and liabilities were as follows: As of December 31, (millions) 2017 2016 Deferred Tax Assets: Net operating loss and tax credit carryforwards $ 477 $ 599 Pension and postretirement benefits 86 112 Reserves not deductible until paid 14 20 Self insurance 2 2 Capitalized interest 7 13 Inventories 4 6 Share-based compensation 14 28 Other 7 4 Deferred tax assets before valuation allowance 611 784 Valuation allowance (175 ) (51 ) Total deferred tax assets $ 436 $ 733 Deferred Tax Liabilities: Property, plant and equipment 153 245 Other — — Total deferred tax liabilities $ 153 $ 245 Net deferred tax assets $ 283 $ 488
Reconciliation of the beginning and ending amount of unrecognized tax benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: (millions) 2017 2016 2015 Balance as of January 1 $ 15 $ 18 $ 22 Tax positions related to the current period: Gross increase — — 4 Gross decrease — — — Tax positions related to prior periods: Gross increase — — — Gross decrease (1 ) (3 ) (1 ) Settlements — — (6 ) Lapse of statutes of limitations (2 ) — (1 ) Balance as of December 31 $ 12 $ 15 $ 18

Lease Commitments (Tables)

Lease Commitments (Tables)	12 Months Ended
	Dec. 31, 2017
Lease Commitments [Abstract]
Schedule of future minimum lease payments required under operating leases	Future minimum lease payments required under operating leases with initial or remaining noncancelable terms in excess of one year as of December 31, 2017 were as follows: (millions) 2018 2019 2020 2021 2022 After 2022 Future minimum lease payments $ 36 $ 31 $ 25 $ 19 $ 10 $ 9

Quarterly Financial Data (una45

Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial information	Quarter (millions, except per-share data) First Second Third Fourth 2017 Net sales $ 767 $ 811 $ 795 $ 831 Gross profit 164 168 163 170 Operating profit 91 96 93 87 Income (loss) from continuing operations (b) 55 46 66 (70 ) (Loss) income from discontinued operations, net of tax — (10 ) — 1 Net income (loss) (b) 55 36 66 (69 ) Income per average common share: Basic (a) $ 0.38 $ 0.25 $ 0.47 $ (0.49 ) Diluted (a) 0.37 0.24 0.46 (0.49 ) 2016 Net sales $ 747 $ 769 $ 767 $ 734 Gross profit 181 193 181 150 Operating profit 116 122 97 59 Income from continuing operations (c) 60 67 56 28 Gain on sale of discontinued operations, net of tax — — — 279 Income from discontinued operations, net of tax 7 7 6 — Net income (c) 67 74 62 307 Income per average common share: Basic (a) $ 0.46 $ 0.50 $ 0.43 $ 2.10 Diluted (a) 0.46 0.50 0.42 2.07 (a) The sum of the four quarters is not necessarily the same as the total for the year. (b) Income from continuing operations and net income included a loss on extinguishment of debt of $22 million for the second quarter of 2017 and income tax expense of $145 million related to the 2017 Tax Act for the fourth quarter of 2017. See Notes 6 and 15, respectively. (c) Income from continuing operations and net income included a loss on extinguishment of debt of $32 million for the fourth quarter of 2016. See Note 6.

Significant Accounting Polici46

Significant Accounting Policies - Segments (Details)	12 Months Ended
	Dec. 31, 2017divisionssegment
Accounting Policies [Abstract]
Number of divisions | divisions	3
Number of reportable segments | segment	5

Significant Accounting Polici47

Significant Accounting Policies - Consolidation and Presentation (Details)	Dec. 31, 2017
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%

Significant Accounting Polici48

Significant Accounting Policies - Advertising (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Advertising expense	$ 10	$ 12	$ 16

Significant Accounting Polici49

Significant Accounting Policies - Research and Development (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Research and development expenditures	$ 23	$ 24	$ 23

Significant Accounting Polici50

Significant Accounting Policies - Income Taxes (Details)	12 Months Ended
	Dec. 31, 2017
Valuation Allowance [Line Items]
Recovery of demand troughs	4 years
Threshold period for cumulative losses	4 years
Minimum
Valuation Allowance [Line Items]
Economic cycle	7 years
Maximum
Valuation Allowance [Line Items]
Economic cycle	10 years

Significant Accounting Polici51

Significant Accounting Policies - Earnings Per Share (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock options, RSUs, MSUs and performance shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted earnings (loss) per share (in shares)	0.7	1.5	1.9
Deferred shares associated with a deferred compensation program for non-employee directors
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted earnings (loss) per share (in shares)	0.2	0.2	0

Significant Accounting Polici52

Significant Accounting Policies - Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Capitalized interest	$ 3	$ 1	$ 3
Buildings and improvements
Property, Plant and Equipment [Line Items]
Expected useful life	50 years
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Expected useful life	10 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Expected useful life	25 years
Computer software and systems development costs | Minimum
Property, Plant and Equipment [Line Items]
Expected useful life	5 years
Computer software and systems development costs | Maximum
Property, Plant and Equipment [Line Items]
Expected useful life	7 years

Significant Accounting Polici53

Significant Accounting Policies - Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Indefinite-lived intangible assets	$ 19	$ 8
Finite-lived intangible assets	$ 8	$ 0

Significant Accounting Polici54

Significant Accounting Policies - Goodwill (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Goodwill	$ 16	$ 0

Significant Accounting Polici55

Significant Accounting Policies - Derivative instruments (Details)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Typical hedging period	6 years
Period of anticipated natural gas purchases typically hedged	12 months

Significant Accounting Polici56

Significant Accounting Policies - Foreign Currency Translation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Transaction gain (loss)	$ (4)	$ 3	$ (7)

Significant Accounting Polici57

Significant Accounting Policies - Investments in Unconcolidated Joint Ventures (Details) $ in Millions	Dec. 31, 2017USD ($)
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Contingent consideration amount (up to)	$ 50

Recent Accounting Pronounceme58

Recent Accounting Pronouncements - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Millions	Jan. 01, 2018	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impact due to adoption of new ASU adoption		$ 25
Retained Earnings (Deficit)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impact due to adoption of new ASU adoption		25
Retained Earnings (Deficit) | Accounting Standards Update 2016-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impact due to adoption of new ASU adoption		$ 25
Subsequent Event | Accounting Standards Update 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash	$ 9
Subsequent Event | Retained Earnings (Deficit) | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impact due to adoption of new ASU adoption	$ 2

Recent Accounting Pronounceme59

Recent Accounting Pronouncements - Recently Issued Accounting Pronouncements (Details) - Accounting Standards Update 2017-07 - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Gross profit
Recently Issued Accounting Pronouncements [Line Items]
Reported after adoption of new accounting pronouncement	$ 656	$ 700
Financial statement line item as reported	665	705
Operating profit
Recently Issued Accounting Pronouncements [Line Items]
Reported after adoption of new accounting pronouncement	353	396
Financial statement line item as reported	367	394
Other net periodic postretirement benefit (costs)
Recently Issued Accounting Pronouncements [Line Items]
Reported after adoption of new accounting pronouncement	14	(2)
Financial statement line item as reported	0	0
Net income
Recently Issued Accounting Pronouncements [Line Items]
Reported after adoption of new accounting pronouncement	88	510
Financial statement line item as reported	$ 88	$ 510

Acquisitions and Dispositions -

Acquisitions and Dispositions - Acquisition of Ceilings Plus (Details) - Ceilings Plus $ in Millions	Nov. 30, 2017USD ($)
Business Acquisition [Line Items]
Purchase price of acquisition	$ 52
Fair value of tangible assets acquired, less liabilities assumed	16
Fair value of intangible assets acquired	20
Goodwill, acquired	$ 16

Acquisitions and Dispositions61

Acquisitions and Dispositions - Discontinued Operations (Details) - USD ($) $ in Millions	2 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of discontinued operations, net of tax						$ 279	$ 0	$ 0	$ 0	$ 0	$ 279	$ 0
(Loss) income from discontinued operations, net of tax		$ 1	$ 0	$ (10)	$ 0	$ 0	$ 6	$ 7	$ 7	(9)	20	15
Cash inflow from discontinued operations	$ 102
L&W Supply
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales										510
Cash inflow from discontinued operations										489
Sales sold to third party customers											568	531
L&W Supply | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration for discontinued operations													$ 675
Gain on sale of discontinued operations, net of tax											279	$ 0
(Loss) income from discontinued operations, net of tax										(8)
European Operations | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations, net of tax										$ (1)	$ (2)

Acquisitions and Dispositions62

Acquisitions and Dispositions - Summarized Income Statement (Details) - USD ($) $ in Millions	3 Months Ended								10 Months Ended	12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Oct. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of discontinued operations					$ 279	$ 0	$ 0	$ 0		$ 0	$ 279	$ 0
(Loss) income from discontinued operations, net of tax	$ 1	$ 0	$ (10)	$ 0	$ 0	$ 6	$ 7	$ 7		(9)	20	15
L&W Supply | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales											1,252	1,428
Cost of products sold											1,196	1,387
Gross profit											56	41
Selling and administrative expenses											22	15
Operating profit											34	26
Income tax expense											12	11
Net income from discontinued operations											22	15
Gain on sale of discontinued operations											279	$ 0
Transaction costs related to sale									$ 8
(Loss) income from discontinued operations, net of tax										(8)
European Operations | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Loss) income from discontinued operations, net of tax										$ (1)	$ (2)

Equity Method Investments - Sch

Equity Method Investments - Schedule of Investments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 686	$ 628
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%
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 679	$ 621
Ownership percentage interest	50.00%	50.00%
Other equity method investments
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 7	$ 7
Other equity method investments | Minimum
Schedule of Equity Method Investments [Line Items]
Ownership percentage interest	33.00%	33.00%
Other equity method investments | Maximum
Schedule of Equity Method Investments [Line Items]
Ownership percentage interest	50.00%	50.00%

Equity Method Investments - Tex

Equity Method Investments - Textuals (Details) € in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2015EUR (€)
Schedule of Equity Method Investments [Line Items]
Cash dividends received		$ 42	$ 47	$ 38
Translation gain (loss)		58	(53)	(67)
Purchase price of joint venture				52	€ 48
Income taxes payable on sale				5
Income and gain from the sale of equity method investment to related party		$ 0	0	13
Years in performance target	3 years	5 years
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Loan receivable from related party		$ 13	$ 15
Knauf
Schedule of Equity Method Investments [Line Items]
Percentage of beneficial ownership of affiliates		10.00%
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Ownership percentage interest		50.00%	50.00%
Cash dividends received		$ 42
Consolidated retained earnings which represents undistributed earnings		60
Contingent consideration amount (up to)		50
Translation gain (loss)		$ 40	$ (30)	$ (23)
Knauf USG
Schedule of Equity Method Investments [Line Items]
Ownership percentage interest				50.00%	50.00%
Gain on sale of investment				$ 6

Equity Method Investments - Sta

Equity Method Investments - Statement of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	$ 59	$ 49	$ 50
USG Boral Building Products
Schedule of Equity Method Investments [Line Items]
Net sales	1,200	1,052	1,003
Gross profit	369	337	278
Operating profit	160	133	124
Net income before taxes	174	142	132
Net income	121	95	101
Net income attributable to USG Boral Building Products	117	99	96
Income (loss) from equity method investments	59	49	48
Other equity method investments
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	$ 0	0	$ 2
China | Operating profit
Schedule of Equity Method Investments [Line Items]
Long-lived asset impairment charges		8
China | Equity Method Income
Schedule of Equity Method Investments [Line Items]
Long-lived asset impairment charges		4
Oman | Operating profit
Schedule of Equity Method Investments [Line Items]
Long-lived asset impairment charges		14
Oman | Equity Method Income
Schedule of Equity Method Investments [Line Items]
Long-lived asset impairment charges		$ 4

Equity Method Investments - Bal

Equity Method Investments - Balance Sheet (Details) - USG Boral Building Products - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Current assets	$ 438	$ 389
Non-current assets	981	903
Current liabilities	255	211
Long-term debt	10	37
Other non-current liabilities	12	17
Shareholders' equity	1,142	1,027
Current portion of long-term debt	16	15
Shareholders' equity related to non-controlling interests	$ 66	$ 50

Marketable Securities - Investm

Marketable Securities - Investments in Marketable Securities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 99	$ 91
Fair Value	99	91
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	68	69
Fair Value	68	69
U.S. government and agency debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6	14
Fair Value	6	14
Asset-backed debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11	2
Fair Value	11	2
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	13	6
Fair Value	13	6
Municipal debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1	0
Fair Value	$ 1	$ 0

Marketable Securities - Contrac

Marketable Securities - Contractual Maturities of Marketable Securities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Amortized Cost
Due in 1 year or less	$ 62
Due in 1-5 years	37
Total marketable securities	99
Fair Value
Due in 1 year or less	62
Due in 1-5 years	37
Total marketable securities	$ 99	$ 91

Debt - Total Debt (Details)

Debt - Total Debt (Details) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term debt, gross	$ 1,089			$ 1,089
Less: Unamortized debt issuance costs	11			6
Total	1,078			1,083
4.875% senior notes due 2027
Debt Instrument [Line Items]
Long-term debt, gross	$ 500			0
Less: Unamortized debt issuance costs			$ 7
Stated interest rate	4.875%	4.875%
5.5% senior notes due 2025
Debt Instrument [Line Items]
Long-term debt, gross	$ 350			350
Less: Unamortized debt issuance costs					$ 6
Stated interest rate	5.50%				5.50%
7.75% senior notes due 2018
Debt Instrument [Line Items]
Long-term debt, gross	$ 0			$ 500
Stated interest rate	7.75%			7.75%
Industrial revenue bonds (due 2028 through 2034)
Debt Instrument [Line Items]
Long-term debt, gross	$ 239			$ 239

Debt - Issuance of Senior Notes

Debt - Issuance of Senior Notes and Repurchases and Redemptions of Senior Notes (Details) - USD ($)	3 Months Ended		12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2017
Debt Instrument [Line Items]
Debt issuance cost		$ 6,000,000	$ 11,000,000	$ 6,000,000
Premiums paid on early redemption of debt		30,000,000		30,000,000
Accrued interest on early redemption of debt		9,000,000		9,000,000
Gain (loss) on early extinguishment of debt	$ (22,000,000)	$ (32,000,000)	$ (22,000,000)	$ (37,000,000)	$ (19,000,000)
4.875% senior notes due 2027
Debt Instrument [Line Items]
Face amount of notes	500,000,000
Stated interest rate			4.875%			4.875%
Debt issuance cost	7,000,000
5.5% senior notes due 2025
Debt Instrument [Line Items]
Face amount of notes					$ 350,000,000
Stated interest rate			5.50%		5.50%
Debt issuance cost					$ 6,000,000
7.75% senior notes due 2018
Debt Instrument [Line Items]
Stated interest rate		7.75%	7.75%	7.75%
Repurchase amount			$ 500,000,000
Aggregate consideration			536,000,000
Premiums paid on early redemption of debt	20,000,000
Accrued interest on early redemption of debt	$ 16,000,000
Gain (loss) on early extinguishment of debt			$ (21,000,000)
6.3% senior notes due 2016
Debt Instrument [Line Items]
Stated interest rate		6.30%		6.30%
Repurchase amount		$ 500,000,000		$ 500,000,000
7.875% senior notes due 2020
Debt Instrument [Line Items]
Stated interest rate		7.875%		7.875%
Repurchase amount		$ 250,000,000		$ 250,000,000
5.875% senior notes due 2021
Debt Instrument [Line Items]
Stated interest rate		5.875%		5.875%
Repurchase amount		$ 350,000,000		$ 350,000,000
8.375% senior notes due 2018
Debt Instrument [Line Items]
Stated interest rate					8.375%
Repurchase amount					$ 350,000,000
Aggregate consideration					$ 377,000,000

Debt - Senior Notes (Details)

Debt - Senior Notes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term debt, gross	$ 1,089		$ 1,089
5.5% senior notes due 2025
Debt Instrument [Line Items]
Stated interest rate	5.50%			5.50%
Long-term debt, gross	$ 350		350
Percentage of purchase price of notes at their principal amount	101.00%
Percentage of principal amount of the notes being redeemed	100.00%
4.875% senior notes due 2027
Debt Instrument [Line Items]
Stated interest rate	4.875%	4.875%
Long-term debt, gross	$ 500		$ 0
Percentage of purchase price of notes at their principal amount	101.00%
Percentage of principal amount of the notes being redeemed	100.00%

Debt - Credit Facility (Details

Debt - Credit Facility (Details) - USD ($)	3 Months Ended		12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Loss on extinguishment of debt	$ 22,000,000	$ 32,000,000	$ 22,000,000	$ 37,000,000	$ 19,000,000
Debt issuance cost		6,000,000	11,000,000	6,000,000
Line of credit
Line of Credit Facility [Line Items]
Maximum borrowing limit		$ 180,000,000	220,000,000	$ 180,000,000
Loss on extinguishment of debt			1,000,000
Debt issuance cost			1,000,000
Current borrowing capacity			155,000,000
Letters of credit outstanding			$ 29,000,000

Debt - Industrial Revenue Bonds

Debt - Industrial Revenue Bonds (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Long-term debt, gross	$ 1,089	$ 1,089
Industrial revenue bonds
Line of Credit Facility [Line Items]
Long-term debt, gross	$ 239	$ 239
Weighted average interest rate	5.875%
Minimum | Industrial revenue bonds
Line of Credit Facility [Line Items]
Stated interest rate	5.50%
Maximum | Industrial revenue bonds
Line of Credit Facility [Line Items]
Stated interest rate	6.40%

Debt - Other Information (Detai

Debt - Other Information (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Fair value of debt	$ 1,134	$ 1,129
Accrued interest	12	$ 31
Debt maturities (principal amounts)
2018 through 2022	0
After 2,022	$ 1,089

Derivative Instruments - Textua

Derivative Instruments - Textuals (Details) MMBTU in Millions	Dec. 22, 2015USD ($)	Dec. 31, 2017USD ($)MMBTU	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Net liability position of derivatives		$ 15,000,000
Collateral provided to counterparties related to derivatives		$ 13,000,000
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain reclassified from AOCI to earnings	$ 1,000,000
Foreign exchange contracts | Derivatives in Net Investment Hedging Relationships
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of FX Instruments				$ 35,000,000
Commodity contracts | Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of Commodity Instruments (in mmBTUs) | MMBTU		38
Loss on cash flow hedge ineffectiveness		$ 0	$ 0	$ 0
Purchases of products and services | Foreign exchange contracts | Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Notional Amount of FX Instruments		$ 95,000,000

Derivative Instruments - Pretax

Derivative Instruments - Pretax Effects of Derivative Instruments (Details) - USD ($) $ in Millions	Dec. 22, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from AOCI into Income (Effective Portion)	$ 1
Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives (Effective Portion)		$ (24)	$ 3	$ (1)
Amount of Gain or (Loss) Reclassified from AOCI into Income (Effective Portion)		(6)	(10)	(7)
Derivatives Designated as Hedging Instruments | Commodity contracts | Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives (Effective Portion)		(19)	6	(14)
Derivatives Designated as Hedging Instruments | Commodity contracts | Cost of products sold | Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from AOCI into Income (Effective Portion)		(4)	(15)	(15)
Derivatives Designated as Hedging Instruments | Foreign exchange contracts | Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives (Effective Portion)		(5)	(3)	12
Derivatives Designated as Hedging Instruments | Foreign exchange contracts | Derivatives in Net Investment Hedging Relationships
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives (Effective Portion)		0	0	1
Derivatives Designated as Hedging Instruments | Foreign exchange contracts | Cost of products sold | Derivatives Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from AOCI into Income (Effective Portion)		(2)	5	7
Derivatives Designated as Hedging Instruments | Foreign exchange contracts | Income and gain from the sale of equity method investment to related party | Derivatives in Net Investment Hedging Relationships
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from AOCI into Income (Effective Portion)		0	0	1
Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivatives		(1)	1	(1)
Derivatives Not Designated as Hedging Instruments | Commodity contracts | Cost of products sold
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivatives		(1)	1	(3)
Derivatives Not Designated as Hedging Instruments | Foreign exchange contracts | Other (income) expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivatives		$ 0	$ 0	$ 2

Derivative Instruments - Fair V

Derivative Instruments - Fair Values of Derivative Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair values of derivative instruments on the consolidated balance sheets
Total assets	$ 2	$ 13
Total liabilities	17	10
Derivatives Not Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total assets	0	1
Total liabilities	0	0
Commodity contracts | Other current assets | Derivatives Not Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total assets	0	1
Commodity contracts | Other assets | Derivatives Not Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total assets	0	0
Commodity contracts | Accrued expenses | Derivatives Not Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total liabilities	0	0
Commodity contracts | Other liabilities | Derivatives Not Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total liabilities	0	0
Derivatives Designated as Hedging Instruments | Derivatives Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total assets	2	12
Total liabilities	17	10
Derivatives Designated as Hedging Instruments | Commodity contracts | Other current assets | Derivatives Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total assets	1	8
Derivatives Designated as Hedging Instruments | Commodity contracts | Other assets | Derivatives Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total assets	1	3
Derivatives Designated as Hedging Instruments | Commodity contracts | Accrued expenses | Derivatives Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total liabilities	6	4
Derivatives Designated as Hedging Instruments | Commodity contracts | Other liabilities | Derivatives Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total liabilities	8	5
Derivatives Designated as Hedging Instruments | Foreign exchange contracts | Other current assets | Derivatives Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total assets	0	1
Derivatives Designated as Hedging Instruments | Foreign exchange contracts | Accrued expenses | Derivatives Designated as Hedging Instruments
Fair values of derivative instruments on the consolidated balance sheets
Total liabilities	$ 3	$ 1

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 148	$ 72
Equity mutual funds	6	5
Marketable securities	99	91
Derivative assets	2	13
Derivative liabilities	(17)	(10)
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	68	69
U.S. government and agency debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	6	14
Asset-backed debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	11	2
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	13	6
Municipal debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	1	0
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	124	38
Equity mutual funds	6	5
Derivative assets	0	0
Derivative liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government and agency debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	24	34
Equity mutual funds	0	0
Derivative assets	2	13
Derivative liabilities	(17)	(10)
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	68	69
Significant Other Observable Inputs (Level 2) | U.S. government and agency debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	6	14
Significant Other Observable Inputs (Level 2) | Asset-backed debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	11	2
Significant Other Observable Inputs (Level 2) | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	13	6
Significant Other Observable Inputs (Level 2) | Municipal debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	1	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Equity mutual funds	0	0
Derivative assets	0	0
Derivative liabilities	0	0
Significant Unobservable Inputs (Level 3) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Significant Unobservable Inputs (Level 3) | U.S. government and agency debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Significant Unobservable Inputs (Level 3) | Asset-backed debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Significant Unobservable Inputs (Level 3) | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Significant Unobservable Inputs (Level 3) | Municipal debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	$ 0	$ 0

Employee Retirement Plans - Tex

Employee Retirement Plans - Textuals (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Contribution Plans Disclosure [Abstract]
Total charges for defined contribution plans	$ 8,000,000	$ 5,000,000	$ 6,000,000
Pension
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	25,000,000	35,000,000	1,000,000
Net periodic benefit cost (credit)	59,000,000	79,000,000	72,000,000
Accumulated benefit obligation	1,506,000,000	1,396,000,000
Actuarial gain (loss)	(202,000,000)	$ (112,000,000)
Net actuarial loss	31,000,000
Expected amortization of prior service cost (credit)	$ 0
Minimum funded percentage of ABO	100.00%
Expected return on plan assets (as a percent)	6.54%	6.66%
Estimated future employer benefit plan contribution	$ 63,000,000
Expected future benefit payments in next twelve months	120,000,000
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (credit)	(16,000,000)	$ (39,000,000)	(23,000,000)
Curtailment gain	0	20,000,000	0
Actuarial gain (loss)	(10,000,000)	5,000,000
Net actuarial loss	1,000,000
Expected amortization of prior service cost (credit)	(23,000,000)
Expected future benefit payments in next twelve months	$ 9,000,000
Gain on sale of discontinued operations | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Curtailment gain		$ 20,000,000
Domestic Plan
Defined Benefit Plan Disclosure [Line Items]
Annual increase to contributions health care cost (as a percent)	3.00%
Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Assumed health care cost trend rate	5.95%	7.75%
Ultimate health care cost trend rate	4.00%	4.00%
USG Corporation Pension Plan - L&W Supply | Pension
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	$ 25,000,000	$ 26,000,000
Net periodic benefit cost (credit)	(1,000,000)	7,000,000	12,000,000
USG Corporation Pension Plan - L&W Supply | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (credit)	(1,000,000)	(3,000,000)	$ (3,000,000)
USG Corporation Pension Plan - L&W Supply | Gain on sale of discontinued operations | Pension
Defined Benefit Plan Disclosure [Line Items]
Settlement charge	$ 0	$ 15,000,000

Employee Retirement Plans - Com

Employee Retirement Plans - Components of Net Pension and Postretirement Benefit Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost of benefits earned	$ 44	$ 45	$ 49
Interest cost on projected benefit obligation	61	66	66
Expected return on plan assets	(93)	(89)	(83)
Settlement	25	35	1
Net amortization	22	22	39
Defined benefit plan, net periodic benefit cost	59	79	72
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost of benefits earned	2	2	2
Interest cost on projected benefit obligation	5	6	6
Curtailment	0	(20)	0
Net amortization	(23)	(27)	(31)
Defined benefit plan, net periodic benefit cost	(16)	(39)	(23)
Cost of products sold | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement	10	7
Selling and administrative expenses | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement	2	4
Gain on sale of discontinued operations | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Curtailment		(20)
USG Corporation Pension Plan - L&W Supply | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement	25	26
Defined benefit plan, net periodic benefit cost	(1)	7	12
USG Corporation Pension Plan - L&W Supply | Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, net periodic benefit cost	(1)	(3)	$ (3)
USG Corporation Pension Plan - L&W Supply | (Loss) income from discontinued operations | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement	13	0
USG Corporation Pension Plan - L&W Supply | Gain on sale of discontinued operations | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement	$ 0	15
USG Corporation Pension Plan - Other | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement		$ 9

Employee Retirement Plans - Acc

Employee Retirement Plans - Accumulated Benefit Obligation (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Selected information for pension plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	$ (35)	$ (39)
Fair value of plan assets	3	2
Selected information for pension plans with benefit obligations in excess of plan assets:
Benefit obligation	(1,769)	(1,384)
Fair value of plan assets	$ 1,576	$ 1,205

Employee Retirement Plans - Pro

Employee Retirement Plans - Projected Benefit Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in Plan Assets:
Fair value as of beginning of period	$ 1,435
Fair value as of end of period	1,577	$ 1,435
Components on the Consolidated Balance Sheets:
Current liabilities	(17)	(24)
Noncurrent liabilities	(326)	(290)
Pension
Change in Benefit Obligation:
Benefit obligation as of beginning of period	1,610	1,564
Service cost	44	45	$ 49
Interest cost	61	66	66
Settlements	(121)	(123)
Curtailments	0	(37)
Participant contributions	9	11
Benefits paid	(51)	(33)
Actuarial (gain) loss	202	112
Foreign currency translation	16	5
Benefit obligation as of end of period	1,770	1,610	1,564
Change in Plan Assets:
Fair value as of beginning of period	1,435	1,301
Actual return on plan assets	217	107
Employer contributions	71	167
Participant contributions	9	11
Benefits paid	(51)	(33)
Settlements	(121)	(123)
Foreign currency translation	17	5
Fair value as of end of period	1,577	1,435	1,301
Funded status	(193)	(175)
Components on the Consolidated Balance Sheets:
Noncurrent assets	0	4
Current liabilities	(8)	(16)
Noncurrent liabilities	(185)	(163)
Net liability as of December 31	(193)	(175)
Pretax Components in AOCI:
Net actuarial loss	421	388
Prior service credit	0	(1)
Total as of end of year	421	387
Postretirement
Change in Benefit Obligation:
Benefit obligation as of beginning of period	135	144
Service cost	2	2	2
Interest cost	5	6	6
Settlements	0	0
Curtailments	0	(7)
Participant contributions	0	0
Benefits paid	(6)	(7)
Actuarial (gain) loss	10	(5)
Foreign currency translation	4	2
Benefit obligation as of end of period	150	135	144
Change in Plan Assets:
Fair value as of beginning of period	0	0
Actual return on plan assets	0	0
Employer contributions	6	7
Participant contributions	0	0
Benefits paid	(6)	(7)
Settlements	0	0
Foreign currency translation	0	0
Fair value as of end of period	0	0	$ 0
Funded status	(150)	(135)
Components on the Consolidated Balance Sheets:
Noncurrent assets	0	0
Current liabilities	(9)	(8)
Noncurrent liabilities	(141)	(127)
Net liability as of December 31	(150)	(135)
Pretax Components in AOCI:
Net actuarial loss	11	0
Prior service credit	(42)	(65)
Total as of end of year	$ (31)	$ (65)

Employee Retirement Plans - Ass

Employee Retirement Plans - Assumptions (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Weighted average assumptions used to determine benefit obligations as of December 31:
Compensation increase rate	3.54%	3.55%
Weighted average assumptions used to determine net cost for years ended December 31:
Compensation increase rate	3.55%	3.55%
Pension
Weighted average assumptions used to determine benefit obligations as of December 31:
Discount rate	3.55%	4.02%
Weighted average assumptions used to determine net cost for years ended December 31:
Discount rate	4.02%	4.43%
Expected return on plan assets (as a percent)	6.54%	6.66%
Postretirement
Weighted average assumptions used to determine benefit obligations as of December 31:
Discount rate	3.42%	3.90%
Weighted average assumptions used to determine net cost for years ended December 31:
Discount rate	3.90%	4.24%

Employee Retirement Plans - One

Employee Retirement Plans - One Percentage Point Change Effects (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
Effect on total service and interest cost, one-percentage-point increase	$ 1
Effect on total service and interest cost, one-percentage-point decrease	0
Effect on postretirement benefit obligation, one-percentage-point increase	13
Effect on postretirement benefit obligation, one-percentage-point decrease	$ (10)

Employee Retirement Plans - Tar

Employee Retirement Plans - Target Asset Allocation and Acceptable Ranges (Details)	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	100.00%
Equity
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	36.00%
Fixed income
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	54.00%
Limited partnerships
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	5.00%
Other real assets
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	5.00%
Cash equivalents and short-term investments
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	0.00%
Minimum | Equity
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	32.00%
Minimum | Fixed income
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	45.00%
Minimum | Limited partnerships
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	1.00%
Minimum | Other real assets
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	2.00%
Minimum | Cash equivalents and short-term investments
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	0.00%
Maximum | Equity
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	40.00%
Maximum | Fixed income
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	63.00%
Maximum | Limited partnerships
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	8.00%
Maximum | Other real assets
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	9.00%
Maximum | Cash equivalents and short-term investments
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations (as a percent)	5.00%

Employee Retirement Plans - Fai

Employee Retirement Plans - Fair Values by Hierarchy of Inputs (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,577	$ 1,435
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	131	142	$ 144
Common and preferred stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	66
Common and preferred stock | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	66
Common and preferred stock | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Common and preferred stock | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Commingled/pooled/mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	553	490
Commingled/pooled/mutual funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Commingled/pooled/mutual funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	553	490
Commingled/pooled/mutual funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Total equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	645	556
Total equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	66
Total equity | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	553	490
Total equity | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. government and agency debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8	194
U.S. government and agency debt securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
U.S. government and agency debt securities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8	194
U.S. government and agency debt securities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. government and agency debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	68	54
Non-U.S. government and agency debt securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Non-U.S. government and agency debt securities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	68	54
Non-U.S. government and agency debt securities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Investment-grade debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	334	197
Investment-grade debt securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Investment-grade debt securities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	334	197
Investment-grade debt securities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
High-yield debt securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42	53
High-yield debt securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
High-yield debt securities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42	53
High-yield debt securities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Commingled/pooled funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	305	165
Commingled/pooled funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Commingled/pooled funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	305	165
Commingled/pooled funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mortgage backed securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	3
Mortgage backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mortgage backed securities | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	3
Mortgage backed securities | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14	11
Other | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13	10
Other | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	1
Total fixed income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	772	677
Total fixed income | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Total fixed income | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	771	676
Total fixed income | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	1	1
Limited partnerships
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	91	103
Limited partnerships | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Limited partnerships | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Limited partnerships | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	91	103	106
Other Real Estate Assets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	57	54
Other Real Estate Assets | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Other Real Estate Assets | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18	16
Other Real Estate Assets | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	39	38	$ 37
Cash equivalents and short-term investments
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14	11
Cash equivalents and short-term investments | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash equivalents and short-term investments | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14	11
Cash equivalents and short-term investments | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Total
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,579	1,401
Total | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	66
Total | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,356	1,193
Total | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	131	142
Cash on hand
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Receivables
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2	35
Accounts payable
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 4	$ 1

Employee Retirement Plans - Rec

Employee Retirement Plans - Reconciliation of Change in Fair Value Measurement of Defined Benefit Plans' Consolidated Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Change in Plan Assets:
Fair value as of beginning of period	$ 1,435
Fair value as of end of period	1,577	$ 1,435
Significant Unobservable Inputs (Level 3)
Change in Plan Assets:
Fair value as of beginning of period	142	144
Realized gains (losses)	16	6
Unrealized gains (losses)	1	(1)
Purchases	9	1
Sales	(37)	(8)
Settlements	0	0
Net transfers into (out of) Level 3	0	0
Fair value as of end of period	131	142
Fixed income
Change in Plan Assets:
Fair value as of beginning of period	677
Fair value as of end of period	772	677
Fixed income | Significant Unobservable Inputs (Level 3)
Change in Plan Assets:
Fair value as of beginning of period	1	1
Realized gains (losses)	0	0
Unrealized gains (losses)	0	0
Purchases	0	0
Sales	0	0
Settlements	0	0
Net transfers into (out of) Level 3	0	0
Fair value as of end of period	1	1
Other Real Estate Assets
Change in Plan Assets:
Fair value as of beginning of period	54
Fair value as of end of period	57	54
Other Real Estate Assets | Significant Unobservable Inputs (Level 3)
Change in Plan Assets:
Fair value as of beginning of period	38	37
Realized gains (losses)	1	1
Unrealized gains (losses)	2	2
Purchases	0	0
Sales	(2)	(2)
Settlements	0	0
Net transfers into (out of) Level 3	0	0
Fair value as of end of period	39	38
Limited partnerships
Change in Plan Assets:
Fair value as of beginning of period	103
Fair value as of end of period	91	103
Limited partnerships | Significant Unobservable Inputs (Level 3)
Change in Plan Assets:
Fair value as of beginning of period	103	106
Realized gains (losses)	15	5
Unrealized gains (losses)	(1)	(3)
Purchases	9	1
Sales	(35)	(6)
Settlements	0	0
Net transfers into (out of) Level 3	0	0
Fair value as of end of period	$ 91	$ 103

Employee Retirement Plans - Exp

Employee Retirement Plans - Expected Benefit Payments (Details) $ in Millions	Dec. 31, 2017USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer benefit plan contribution	$ 63
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2,018	120
2,019	125
2,020	137
2,021	134
2,022	141
2023 - 2027	634
Postretirement Benefits
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2,018	9
2,019	9
2,020	8
2,021	8
2,022	8
2023 - 2027	$ 42

Share-Based Compensation - Text

Share-Based Compensation - Textuals (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of shares reserved for future grant under the LTIP (in shares)	7,000,000
Income tax benefits on share based arrangements	$ 0
Share-based Compensation Arrangement by Share-based Payment Award [lLine Items]
Expense for share-based arrangements	18,000,000	$ 18,000,000	$ 14,000,000
Deferred compensation arrangement adjustment to equity	$ 6,000,000
MSUs
Share-based Compensation Arrangement by Share-based Payment Award [lLine Items]
Vesting period	3 years
Minimum number of performance shares earned (as a percent)	0.00%
Maximum number of performance shares earned (as a percent)	150.00%
Awards vested (in shares)	417,001
Number of shares vested (in shares)	554,624
Unrecognized compensation cost	$ 5,000,000
Weighted average period for recognition of unrecognized compensation cost	1 year 8 months
Granted (in shares)	371,000
Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [lLine Items]
Vesting period	3 years
Minimum number of performance shares earned (as a percent)	0.00%
Maximum number of performance shares earned (as a percent)	200.00%
Awards vested (in shares)	99,238
Number of shares vested (in shares)	0
Unrecognized compensation cost	$ 4,000,000
Weighted average period for recognition of unrecognized compensation cost	1 year 9 months 18 days
Granted (in shares)	113,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [lLine Items]
Vesting period	3 years
Awards vested (in shares)	54,000
Unrecognized compensation cost	$ 5,000,000
Weighted average period for recognition of unrecognized compensation cost	2 years 2 months 12 days
Granted (in shares)	133,000
Fair value of RSUs that vested in period	$ 2,000,000	2,000,000	4,000,000
Employee stock option
Share-based Compensation Arrangement by Share-based Payment Award [lLine Items]
Expiration period of stock options	10 years
(Loss) income from discontinued operations
Share-based Compensation Arrangement by Share-based Payment Award [lLine Items]
Expense for share-based arrangements		$ 1,000,000	$ 1,000,000

Share-Based Compensation - MSUs

Share-Based Compensation - MSUs Assumptions (Details) - MSUs - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assumptions:
Weighted average grant date fair value (in dollars per share)	$ 35.79	$ 19.59	$ 30.06
Expected volatility	32.10%	34.02%	42.70%
Risk-free rate	1.39%	0.86%	1.09%
Expected term (in years)	2 years 11 months 14 days	2 years 11 months 13 days	2 years 11 months 12 days
Expected dividends	$ 0	$ 0	$ 0

Share-Based Compensation - MS91

Share-Based Compensation - MSUs Activity (Details) - MSUs - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Weighted Number of Shares
Nonvested at beginning of period (in shares)	1,157,000
Granted (in shares)	371,000
Vested (in shares)	(417,001)
Forfeited (in shares)	(14,000)
Nonvested at end of period (in shares)	1,097,000	1,157,000
Weighted Average Grant Date Fair Value
Nonvested at January 1 (in dollars per share)	$ 23.39
Granted (in dollars per share)	35.79	$ 19.59	$ 30.06
Vested (in dollars per share)	30.06
Forfeited (in dollars per share)	26.20
Nonvested at December 31 (in dollars per share)	$ 25.01	$ 23.39

Share-Based Compensation - Perf

Share-Based Compensation - Performance Shares Assumptions (Details) - Performance shares - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assumptions:
Weighted average grant date fair value (in dollars per share)	$ 39.42	$ 21.10	$ 30.63
Expected volatility	32.10%	34.02%	42.70%
Risk-free rate	1.39%	0.86%	1.09%
Expected term (in years)	2 years 11 months 14 days	2 years 11 months 13 days	2 years 11 months 12 days
Expected dividends	$ 0	$ 0	$ 0

Share-Based Compensation - Pe93

Share-Based Compensation - Performance Shares Activity (Details) - Performance shares - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Weighted Number of Shares
Nonvested at beginning of period (in shares)	246,000
Granted (in shares)	113,000
Vested (in shares)	(99,238)
Forfeited (in shares)	(4,000)
Nonvested at end of period (in shares)	256,000	246,000
Weighted Average Grant Date Fair Value
Nonvested at January 1 (in dollars per share)	$ 24.98
Granted (in dollars per share)	39.42	$ 21.10	$ 30.63
Vested (in dollars per share)	30.63
Forfeited (in dollars per share)	26.75
Nonvested at December 31 (in dollars per share)	$ 29.14	$ 24.98

Share-Based Compensation - RSU

Share-Based Compensation - RSU Assumptions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
RSUs
Assumptions:
Weighted average grant date fair value (in dollars per share)	$ 31.57	$ 23.94	$ 28.56

Share-Based Compensation - RSUs

Share-Based Compensation - RSUs Activity (Details) - RSUs - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Shares
Nonvested at beginning of period (in shares)	228
Granted (in shares)	133
Vested (in shares)	(54)
Forfeited (in shares)	(3)
Nonvested at end of period (in shares)	304	228
Weighted Average Grant Date Fair Value
Nonvested at January 1 (in dollars per share)	$ 27.31
Granted (in dollars per share)	31.57	$ 23.94	$ 28.56
Vested (in dollars per share)	31.38
Forfeited (in dollars per share)	29.83
Nonvested at December 31 (in dollars per share)	$ 14.67	$ 27.31

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Stock Options (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Options
Outstanding at beginning of period (in shares)	2,174
Exercised (in shares)	(590)
Canceled (in shares)	(323)
Outstanding at end of period (in shares)	1,261	2,174
Exercisable (in shares)	1,261
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 22.55
Exercised (in dollars per share)	23.88
Canceled (in dollars per share)	46.80
Outstanding at end of period (in dollars per share)	15.72	$ 22.55
Exercisable (in dollars per share)	$ 15.72
Options Activity, Weighted Remaining Contractual Term and Aggregate Intrisic Value
Outstanding weighted average remaining contractual term (years)	2 years 5 months 23 days	2 years 9 months 10 days
Exercisable weighted average remaining contractual term (years)	2 years 5 months 23 days
Outstanding aggregate intrinsic value	$ 28	$ 22
Exercisable aggregate intrinsic value	$ 28
Vested or expected to vest
Number of options	1,261
Weighted average exercise price (in dollars per share)	$ 15.72
Weighted Average Remaining Contractual Term (years)	2 years 5 months 23 days
Aggregate intrinsic value	$ 28
Employee stock option
Vested or expected to vest
Intrinsic value of stock options exercised	7	4	$ 6
Cash received from stock options exercised	14	4	6
Fair value of stock options vested	$ 0	$ 1	$ 1

Supplemental Balance Sheet In97

Supplemental Balance Sheet Information - Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Inventory, Net [Abstract]
Finished goods	$ 140	$ 132
Work in progress	39	37
Raw materials	73	67
Total	$ 252	$ 236

Supplemental Balance Sheet In98

Supplemental Balance Sheet Information - Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Land and mineral deposits	$ 120	$ 116
Buildings and improvements	1,100	1,078
Machinery and equipment	2,595	2,473
Property, plant and equipment, gross	3,815	3,667
Reserves for depreciation and depletion	(2,053)	(1,960)
Total	1,762	1,707
Annual depreciation and depletion expense	$ 129	$ 129

Supplemental Balance Sheet In99

Supplemental Balance Sheet Information - Accrued Expenses (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accrued Liabilities, Current [Abstract]
Self-insurance reserves	$ 12	$ 12
Employee compensation	17	35
Interest	12	31
Derivatives	9	5
Pension and other postretirement benefits	17	24
Environmental	17	18
Other	51	50
Total	$ 135	$ 175

Supplemental Balance Sheet I100

Supplemental Balance Sheet Information - Asset Retirement Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance as of beginning of period	$ 113	$ 119
Accretion expense	7	7
Liabilities incurred	3	2
Changes in estimated cash flows	(4)	(12)
Liabilities settled	(3)	(4)
Foreign currency translation	2	1
Balance as of end of period	$ 118	113
Changes in estimated cash flows related to quarries		$ 8

Supplemental Balance Sheet I101

Supplemental Balance Sheet Information - Changes in Balances of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	$ 1,886	$ 1,436	$ 408
Other comprehensive (loss) income, net of tax	(4)	(71)	24
Balance at end of period	1,845	1,886	1,436
Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	27	20	16
Other comprehensive income (loss) before reclassifications, net of tax	(14)	1	(5)
Less: Amounts reclassified from AOCI, net of tax	(3)	(6)	(9)
Other comprehensive (loss) income, net of tax	(11)	7	4
Balance at end of period	16	27	20
Pension and Other Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(246)	(221)	(302)
Other comprehensive income (loss) before reclassifications, net of tax	(65)	(34)	74
Less: Amounts reclassified from AOCI, net of tax	(14)	(9)	(7)
Other comprehensive (loss) income, net of tax	(51)	(25)	81
Balance at end of period	(297)	(246)	(221)
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(166)	(113)	(52)
Other comprehensive income (loss) before reclassifications, net of tax	58	(53)	(67)
Less: Amounts reclassified from AOCI, net of tax	0	0	(6)
Other comprehensive (loss) income, net of tax	58	(53)	(61)
Balance at end of period	(108)	(166)	(113)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(385)	(314)	(338)
Other comprehensive income (loss) before reclassifications, net of tax	(21)	(86)	2
Less: Amounts reclassified from AOCI, net of tax	(17)	(15)	(22)
Other comprehensive (loss) income, net of tax	(4)	(71)	24
Balance at end of period	$ (389)	$ (385)	$ (314)

Supplemental Balance Sheet I102

Supplemental Balance Sheet Information - Amounts Reclassified from AOCI (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of products sold					$ (2,539)	$ (2,312)	$ (2,263)
Net reclassification from AOCI for cash flow hedges included in income and gain from the sale of equity method investment to related party					0	0	13
Less: Income tax expense on reclassification from AOCI included in income tax expense					238	63	(740)
Selling and administrative expenses					(298)	(304)	(302)
Gain on sale of discontinued operations, net of tax	$ 279	$ 0	$ 0	$ 0	0	279	0
Net income					88	510	991
Derivatives | Reclassification out of accumulated other comprehensive income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of products sold					(6)	(10)	(8)
Net reclassification from AOCI for cash flow hedges included in income and gain from the sale of equity method investment to related party					0	0	1
Less: Income tax expense on reclassification from AOCI included in income tax expense					(3)	(4)	2
Net income					(3)	(6)	(9)
Pension and postretirement benefits | Reclassification out of accumulated other comprehensive income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cost of products sold					(8)	(1)	1
Less: Income tax expense on reclassification from AOCI included in income tax expense					(10)	(7)	(1)
Selling and administrative expenses					(5)	(12)	(5)
Gain on sale of discontinued operations, net of tax					(11)	(3)	(4)
Net income					(14)	(9)	(7)
Foreign Currency Translation | Reclassification out of accumulated other comprehensive income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Selling and administrative expenses					0	0	(6)
Net income					$ 0	$ 0	$ (6)

Supplemental Balance Sheet I103

Supplemental Balance Sheet Information - Textuals (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net after-tax loss on derivatives reclassified from AOCI	$ 6

Long-Lived Asset Impairment 104

Long-Lived Asset Impairment Charges - Impairment Charges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring and Related Activities [Abstract]
Long-lived asset impairment charges	$ 0	$ 10	$ 0
Severance and other charges		$ 2

Gypsum Transportation Limited (

Gypsum Transportation Limited (Details) $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Jun. 30, 2015USD ($)ocean_vessel	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Property, Plant and Equipment [Line Items]
Self-unloading ocean vessels | ocean_vessel									2
Proceeds from sale of assets										$ 2	$ 12	$ 58
Gain on asset disposition										(1)	9	13
Cost to exit shipping operations									$ 6
Gain on disposal of shipping operations, net										0	0	1
Contract termination and (recovery) loss on receivable										0	3	6
Recovered receivable per release and debt settlement agreement											8
Recovered receivable in interest income											1
Recovered receivable in other income											4
Operating profit	$ 87	$ 93	$ 96	$ 91	$ 59	$ 97	$ 122	$ 116		367	394	355
Gypsum Transportation Limited
Property, Plant and Equipment [Line Items]
Operating profit										$ 0	$ 3	$ 7
Self-unloading ocean vessels
Property, Plant and Equipment [Line Items]
Proceeds from sale of assets									42
Gain on asset disposition									$ 7

Segments - Textuals (Details)

Segments - Textuals (Details)	12 Months Ended
	Dec. 31, 2017segment
Segment Reporting [Abstract]
Number of reportable segments	5

Segments - Consolidated Segment

Segments - Consolidated Segments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net Sales:
Net sales	$ 831	$ 795	$ 811	$ 767	$ 734	$ 767	$ 769	$ 747	$ 3,204	$ 3,017	$ 2,913
Operating Profit (Loss):
Operating profit	87	$ 93	$ 96	$ 91	59	$ 97	$ 122	$ 116	367	394	355
Depreciation, Depletion and Amortization:
Depreciation, depletion and amortization									132	134	131
Capital Expenditures:
Capital expenditures									168	83	87
Assets:
Assets	3,851				3,869				3,851	3,869	4,736
Equity method investments	686				628				686	628
Consolidation, Eliminations
Net Sales:
Net sales									(9)	(9)	(9)
Operating Segments | U.S. Wallboard and Surfaces
Net Sales:
Net sales									1,916	1,778	1,720
Operating Profit (Loss):
Operating profit									314	334	298
Depreciation, Depletion and Amortization:
Depreciation, depletion and amortization									91	87	85
Capital Expenditures:
Capital expenditures									104	60	73
Assets:
Assets	1,574				1,540				1,574	1,540	1,590
Operating Segments | U.S. Performance Materials
Net Sales:
Net sales									373	357	321
Operating Profit (Loss):
Operating profit									26	41	31
Depreciation, Depletion and Amortization:
Depreciation, depletion and amortization									9	9	8
Capital Expenditures:
Capital expenditures									31	11	4
Assets:
Assets	172				154				172	154	147
Operating Segments | U.S. Ceilings
Net Sales:
Net sales									477	467	464
Operating Profit (Loss):
Operating profit									95	101	80
Depreciation, Depletion and Amortization:
Depreciation, depletion and amortization									15	15	15
Capital Expenditures:
Capital expenditures									17	4	3
Assets:
Assets	307				225				307	225	267
Operating Segments | Canada
Net Sales:
Net sales									405	389	372
Operating Profit (Loss):
Operating profit									12	26	10
Depreciation, Depletion and Amortization:
Depreciation, depletion and amortization									6	6	6
Capital Expenditures:
Capital expenditures									10	4	4
Assets:
Assets	134				124				134	124	126
Operating Segments | Other
Net Sales:
Net sales									245	220	239
Operating Profit (Loss):
Operating profit									11	(4)	30
Depreciation, Depletion and Amortization:
Depreciation, depletion and amortization									5	7	8
Capital Expenditures:
Capital expenditures									5	3	3
Assets:
Assets	144				135				144	135	160
Eliminations
Net Sales:
Net sales									(212)	(194)	(203)
Operating Profit (Loss):
Operating profit									(1)	0	0
Assets:
Assets	(22)				(17)				(22)	(17)	(76)
Corporate
Operating Profit (Loss):
Operating profit									(90)	(104)	(94)
Depreciation, Depletion and Amortization:
Depreciation, depletion and amortization									6	10	9
Capital Expenditures:
Capital expenditures									1	1	0
Assets:
Assets	856				1,080				856	1,080	1,483
Segment Reconciling Items
Assets:
Equity method investments	686				628				686	628	682
Assets related to discontinued operations	$ 0				$ 0				$ 0	$ 0	$ 357

Segments - Product Information

Segments - Product Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net	$ 831	$ 795	$ 811	$ 767	$ 734	$ 767	$ 769	$ 747	$ 3,204	$ 3,017	$ 2,913
Gypsum
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net									2,331	2,169	2,105
Performance Materials
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net									373	357	321
Ceilings
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net									509	500	496
Consolidation, Eliminations
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net									$ (9)	$ (9)	$ (9)

Segments - Geographic Informati

Segments - Geographic Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Geographic Areas, Revenues from External Customers [Abstract]
Net sales	$ 831	$ 795	$ 811	$ 767	$ 734	$ 767	$ 769	$ 747	$ 3,204	$ 3,017	$ 2,913
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	1,762				1,707				1,762	1,707	1,771
Reportable geographical components | United States
Geographic Areas, Revenues from External Customers [Abstract]
Net sales									2,787	2,625	2,524
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	1,604				1,563				1,604	1,563	1,605
Reportable geographical components | Canada
Geographic Areas, Revenues from External Customers [Abstract]
Net sales									406	389	379
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	90				80				90	80	90
Reportable geographical components | Other Foreign
Geographic Areas, Revenues from External Customers [Abstract]
Net sales									204	189	196
Geographic Areas, Long-Lived Assets [Abstract]
Long-lived assets	$ 68				$ 64				68	64	76
Geographic transfers
Geographic Areas, Revenues from External Customers [Abstract]
Net sales									$ (193)	$ (186)	$ (186)

Segments - UBBP (Details)

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)

Segments - Revenues from Signif

Segments - Revenues from Significant Customers (Details) - Net Sales	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
The Home Depot
Segment Reporting Information [Line Items]
Concentration Risk, Percentage	23.00%	23.00%	23.00%
L&W
Segment Reporting Information [Line Items]
Concentration Risk, Percentage	16.00%	19.00%	18.00%

Income Taxes - Income from Cont

Income Taxes - Income from Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income (loss) before income taxes
U.S.	$ 272	$ 201	$ 152
Foreign	63	73	84
Total	$ 335	$ 274	$ 236

Income Taxes - Income Tax Expen

Income Taxes - Income Tax Expense (Benefit) on Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ (21)	$ 0	$ 0
Foreign	2	5	12
State	2	1	1
Total current	(17)	6	13
Deferred:
Federal	243	41	(631)
Foreign	0	2	(4)
State	12	14	(118)
Total deferred	255	57	(753)
Provision for income tax expense (benefit)	$ 238	$ 63	$ (740)

Income Taxes - Textuals (Detail

Income Taxes - Textuals (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Examination [Line Items]
Amount related to evaluation for need for valuation allowance against deferred tax assets			$ (731,000,000)
Increase / decrease in valuation allowance against deferred tax assets	$ 124,000,000	$ (19,000,000)
Net deferred tax assets	283,000,000	488,000,000
Valuation allowance	175,000,000	51,000,000
Approximate federal net operating loss carryforwards	477,000,000
Approximate federal alternative minimum tax credit carryforwards	32,000,000
Foreign deferred tax assets	223,000,000
Minimum taxable income needed to fully realize the U.S. federal net deferred tax assets	1,663,000,000
State deferred tax assets	$ 169,000,000
Percentage of change in ownership (more than)	50.00%
Period of change in ownership	3 years
Annual U.S. federal NOL utilization	$ 107,000,000
Unrecognized tax benefits, income tax penalties and interest	0	2,000,000
Total amounts of interest and penalties recognized in consolidated statements of operations	0	0	0
Total amount of unrecognized tax benefit that would affect our effective tax rate	$ 12,000,000	$ 14,000,000	$ 17,000,000
Income tax examinations, possible period for resolution	12 months
Lapse of statutes of limitations	$ 2,000,000
Income taxes receivable	$ 12,000,000
Minimum
Income Tax Examination [Line Items]
Period of statutes of limitations	3 years
Maximum
Income Tax Examination [Line Items]
Period of statutes of limitations	5 years
Domestic Tax Authority
Income Tax Examination [Line Items]
Approximate federal alternative minimum tax credit carryforwards	$ 20,000,000

Income Taxes - Differences Betw

Income Taxes - Differences Between Provisions for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation Allowance [Line Items]
Transition tax for accumulated foreign earnings	$ 9
Sequestration of AMT credits	3
Change in tax rate, provisional income tax expense (benefit)	9
Differences between actual provisions for income taxes and provisions for income taxes at the U.S. federal statutory rate (35%)
Taxes on income from continuing operations at U.S. federal statutory rate	117	$ 96	$ 82
Foreign earnings subject to different tax rates	3	(3)	(3)
State income tax, net of federal benefit	9	10	8
Change in valuation allowance	0	0	(827)
Income from equity method investments	(21)	(17)	(16)
Law changes	145	0	0
Prior year return adjustments	(7)	0	0
Benefits from unrecognized tax positions	0	0	(6)
Foreign tax credits	0	(21)	0
Tax expense on distribution of foreign earnings	0	0	20
Other, net	(8)	(2)	2
Provision for income tax expense (benefit)	$ 238	$ 63	$ (740)
Effective income tax rate	71.00%	22.90%	(313.60%)
Foreign Tax Credits
Valuation Allowance [Line Items]
Change in tax rate, deferred tax asset, valuation allowance	$ 106
State Net Operating Losses
Valuation Allowance [Line Items]
Change in tax rate, deferred tax asset, valuation allowance	$ 18

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets:
Net operating loss and tax credit carryforwards	$ 477	$ 599
Pension and postretirement benefits	86	112
Reserves not deductible until paid	14	20
Self insurance	2	2
Capitalized interest	7	13
Inventories	4	6
Share-based compensation	14	28
Other	7	4
Deferred tax assets before valuation allowance	611	784
Valuation allowance	(175)	(51)
Total deferred tax assets	436	733
Deferred Tax Liabilities:
Property, plant and equipment	153	245
Other	0	0
Total deferred tax liabilities	153	245
Net deferred tax assets	$ 283	$ 488

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of the beginning and ending amount of unrecognized tax benefits
Balance as of beginning of period	$ 15	$ 18	$ 22
Tax positions related to the current period:
Gross increase	0	0	4
Gross decrease	0	0	0
Tax positions related to prior periods:
Gross increase	0	0	0
Gross decrease	(1)	(3)	(1)
Settlements	0	0	(6)
Lapse of statutes of limitations	(2)	0	(1)
Balance as of end of period	$ 12	$ 15	$ 18

Stockholder Rights Plan (Detail

Stockholder Rights Plan (Details)	12 Months Ended
	Dec. 31, 2017	Feb. 11, 2015	May 09, 2013
Equity [Abstract]
Period of cumulative change in ownership	3 years
Aggregate increase in common stock owned	50.00%
Ownership interest to cause cumulative change in ownership (or more than) (as a percent)	5.00%
Beneficial owner of common stock percentage (or more than)		4.90%	4.90%
Triggering threshold for rights issued pursuant to the plan	15.00%
Period of review	3 years
Beneficial ownership percentage post standstill period (up to)	50.00%
Beneficial owner of common stock percentage in future (more than)	50.00%
Period of offer to purchase common stock	60 days

Lease Commitments - Textuals (D

Lease Commitments - Textuals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Lease Commitments [Abstract]
Lease expense	$ 38	$ 37	$ 36

Lease Commitments - Future Mini

Lease Commitments - Future Minimum Lease Payments (Details) $ in Millions	Dec. 31, 2017USD ($)
Future minimum lease payments
2,018	$ 36
2,019	31
2,020	25
2,021	19
2,022	10
After 2,022	$ 9

Litigation (Details)

Litigation (Details) $ in Millions	Dec. 31, 2017USD ($)HomebuilderDefendants	Dec. 31, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
Number of defendants named in lawsuit | Defendants	7
Number of homebuilders asserting individual claims | Homebuilder	12
Accrual potential liability for environmental cleanup | $	$ 17	$ 18

Quarterly Financial Data (un122

Quarterly Financial Data (unaudited) - Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 831	$ 795	$ 811	$ 767	$ 734	$ 767	$ 769	$ 747	$ 3,204	$ 3,017	$ 2,913
Gross profit	170	163	168	164	150	181	193	181	665	705	650
Operating profit	87	93	96	91	59	97	122	116	367	394	355
Income (loss) from continuing operations	(70)	66	46	55	28	56	67	60	97	211	976
(Loss) income from discontinued operations, net of tax	1	0	(10)	0	0	6	7	7	(9)	20	15
Gain on sale of discontinued operations, net of tax					279	0	0	0	0	279	0
Net income	$ (69)	$ 66	$ 36	$ 55	$ 307	$ 62	$ 74	$ 67	$ 88	$ 510	$ 991
Income per average common share:
Basic (in dollars per share)	$ (0.49)	$ 0.47	$ 0.25	$ 0.38	$ 2.10	$ 0.43	$ 0.50	$ 0.46	$ 0.67	$ 1.45	$ 6.70
Diluted (in dollars per share)	$ (0.49)	$ 0.46	$ 0.24	$ 0.37	$ 2.07	$ 0.42	$ 0.50	$ 0.46	$ 0.66	$ 1.44	$ 6.62
Loss on extinguishment of debt			$ 22		$ 32				$ 22	$ 37	$ 19
Law changes									$ 145	$ 0	$ 0

Subsequent Event - Subsequent E

Subsequent Event - Subsequent Event (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018
Subsequent Event [Line Items]
Repurchase of common stock	$ 184,000,000
Remaining authorized repurchase of common stock, amount	$ 316,000,000
Subsequent Event
Subsequent Event [Line Items]
Stock repurchase program, increase (decrease), authorized amount		$ 250,000,000
Stock repurchase program, authorized amount		$ 500,000,000

Schedule II - Valuation And 124

Schedule II - Valuation And Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 5	$ 7	$ 14
Charged to costs and expenses	2	1	(6)
Charged to other accounts	0	0	0
Deductions	(1)	(3)	(1)
Balance at end of period	6	5	7
Cash discounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	3	2	1
Charged to costs and expenses	34	34	37
Charged to other accounts	0	0	0
Deductions	(34)	(33)	(36)
Balance at end of period	3	3	2
Income tax valuation allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	51	70	1,023
Charged to costs and expenses	124	0	0
Charged to other accounts	0	0	0
Deductions	0	(19)	(953)
Balance at end of period	$ 175	$ 51	$ 70