United States Steel (X) 10-Q 30 Oct 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 26, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity Registrant Name	United States Steel Corp
Entity Incorporation, State or Country Code	DE
Entity File Number	1-16811
Entity Tax Identification Number	25-1897152
Entity Address, Address Line One	600 Grant Street
Entity Address, City or Town	Pittsburgh
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	15219-2800
City Area Code	412
Local Phone Number	433-1121
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		220,404,216
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001163302
Current Fiscal Year End Date	--12-31
New York Stock Exchange
Entity Information [Line Items]
Title of 12(b) Security	United States Steel Corporation Common Stock
Trading Symbol	X
Security Exchange Name	NYSE
Chicago Stock Exchange
Entity Information [Line Items]
Title of 12(b) Security	United States Steel Corporation Common Stock
Trading Symbol	X
Security Exchange Name	CHX

CONSOLIDATED STATEMENT OF OPERA

CONSOLIDATED STATEMENT OF OPERATIONS (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net sales:
Net sales	$ 2,072	$ 2,702	$ 6,469	$ 9,001
Net sales to related parties (Note 19)	268	367	710	1,112
Total (Note 6)	2,340	3,069	7,179	10,113
Operating expenses (income):
Cost of sales (excludes items shown below)	2,295	2,902	7,174	9,301
Selling, general and administrative expenses	65	63	199	223
Depreciation, depletion and amortization	162	161	481	454
Loss (earnings) from investees	31	(31)	78	(68)
Asset impairment charges (Note 1)	0	0	263	0
Gain on equity investee transactions	0	0	(31)	0
Restructuring and other charges (Note 20)	0	54	130	54
Net (gain) loss on sale of assets	(2)	(1)	(2)	3
Other losses, net	0	1	5	0
Total	2,551	3,149	8,297	9,967
(Loss) earnings before interest and income taxes	(211)	(80)	(1,118)	146
Interest expense	84	32	198	97
Interest income	(1)	(3)	(6)	(13)
Other financial benefits	(30)	(4)	(26)	(2)
Net periodic benefit (income) cost (other than service cost)	(6)	23	(22)	69
Net interest and other financial costs	47	48	144	151
Loss before income taxes	(258)	(128)	(1,262)	(5)
Income tax benefit (Note 12)	(24)	(44)	(48)	(43)
Net (loss) earnings	(234)	(84)	(1,214)	38
Less: Net earnings attributable to noncontrolling interests	0	0	0	0
Net (loss) earnings attributable to United States Steel Corporation	$ (234)	$ (84)	$ (1,214)	$ 38
(Loss) earnings per share attributable to United States Steel Corporation stockholders:
-Basic (in dollars per share)	$ (1.06)	$ (0.49)	$ (6.43)	$ 0.22
-Diluted (in dollars per share)	$ (1.06)	$ (0.49)	$ (6.43)	$ 0.22

CONSOLIDATED STATEMENT OF COMPR

CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net (loss) earnings	$ (234)	$ (84)	$ (1,214)	$ 38
Other comprehensive income (loss), net of tax:
Changes in foreign currency translation adjustments	34	(40)	31	(45)
Changes in pension and other employee benefit accounts	16	30	97	94
Changes in derivative financial instruments	8	(2)	18	2
Total other comprehensive income (loss), net of tax	58	(12)	146	51
Comprehensive (loss) income including noncontrolling interest	(176)	(96)	(1,068)	89
Comprehensive income attributable to noncontrolling interest	0	0	0	0
Comprehensive (loss) income attributable to United States Steel Corporation	$ (176)	$ (96)	$ (1,068)	$ 89

CONSOLIDATED BALANCE SHEET (Una

CONSOLIDATED BALANCE SHEET (Unaudited) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents (Note 7)	$ 1,696	$ 749
Receivables, less allowance of $34 and $28	996	956
Receivables from related parties (Note 19)	103	221
Inventories (Note 8)	1,398	1,785
Other current assets	51	102
Total current assets	4,244	3,813
Long-term restricted cash (Note 7)	89	188
Operating lease assets	225	230
Property, plant and equipment	17,477	17,077
Less accumulated depreciation and depletion	12,047	11,630
Total property, plant and equipment, net	5,430	5,447
Investments and long-term receivables, less allowance of $8 and $5	1,286	1,466
Intangibles – net (Note 9)	131	150
Deferred income tax benefits (Note 12)	21	19
Other noncurrent assets	305	295
Total assets	11,731	11,608
Current liabilities:
Accounts payable and other accrued liabilities	1,533	1,970
Accounts payable to related parties (Note 19)	113	84
Payroll and benefits payable	312	336
Accrued taxes	109	116
Accrued interest	74	45
Current operating lease liabilities	60	60
Short-term debt and current maturities of long-term debt (Note 15)	262	14
Total current liabilities	2,463	2,625
Noncurrent operating lease liabilities	174	177
Long-term debt, less unamortized discount and debt issuance costs (Note 15)	4,628	3,627
Employee benefits	543	532
Deferred income tax liabilities (Note 12)	6	4
Deferred credits and other noncurrent liabilities	413	550
Total liabilities	8,227	7,515
Contingencies and commitments (Note 21)
Stockholders’ Equity (Note 17):
Common stock (229,075,215 and 178,555,206 shares issued) (Note 13)	229	179
Treasury stock, at cost (8,670,999 shares and 8,509,337 shares)	(175)	(173)
Additional paid-in capital	4,398	4,020
(Accumulated deficit) retained earnings	(671)	544
Accumulated other comprehensive loss (Note 18)	(332)	(478)
Total United States Steel Corporation stockholders’ equity	3,449	4,092
Noncontrolling interests	55	1
Total liabilities and stockholders’ equity	$ 11,731	$ 11,608

CONSOLIDATED BALANCE SHEET (U_2

CONSOLIDATED BALANCE SHEET (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Receivables, allowance	$ 34	$ 28
Investments and long-term receivables, allowance	$ 8	$ 5
Common stock, shares issued (in shares)	229,075,215	178,555,206
Treasury stock, shares (in shares)	8,670,999	8,509,337

CONSOLIDATED STATEMENT OF CASH

CONSOLIDATED STATEMENT OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net (loss) earnings	$ (1,214)	$ 38
Adjustments to reconcile to net cash provided by operating activities:
Depreciation, depletion and amortization	481	454
Asset impairment charges (Note 1)	263	0
Gain on equity investee transactions	(31)	0
Restructuring and other charges (Note 20)	130	54
Pensions and other postretirement benefits	(18)	76
Deferred income taxes (Note 12)	(36)	(38)
Net (gain) loss on sale of assets	(2)	3
Equity investee loss (earnings), net of distributions received	78	(64)
Changes in:
Current receivables	(18)	209
Inventories	495	(4)
Current accounts payable and accrued expenses	(267)	(325)
Income taxes receivable/payable	13	27
All other, net	(23)	(34)
Net cash (used in) provided by operating activities	(149)	396
Investing activities:
Capital expenditures	(591)	(978)
Investment in Big River Steel	(3)	0
Proceeds from sale of assets	3	4
Proceeds from sale of ownership interests in equity investees	8	0
Investments, net	(4)	0
Net cash used in investing activities	(587)	(974)
Financing activities:
Issuance of short-term debt, net of financing costs (Note 15)	240	0
Revolving credit facilities - borrowings, net of financing costs (Note 15)	1,474	165
Revolving credit facilities - repayments (Note 15)	(1,633)	0
Issuance of long-term debt, net of financing costs (Note 15)	1,043	0
Repayment of long-term debt (Note 15)	(8)	(4)
Net proceeds from public offering of common stock (Note 23)	410	0
Proceeds from Stelco Option Agreement, net of financing costs	55	0
Common stock repurchased (Note 23)	0	(88)
Dividends paid	(6)	(26)
Taxes paid for equity compensation plans (Note 11)	(1)	(7)
Net cash provided by financing activities	1,574	40
Effect of exchange rate changes on cash	10	(6)
Net increase (decrease) in cash, cash equivalents and restricted cash	848	(544)
Cash, cash equivalents and restricted cash at beginning of year (Note 7)	939	1,040
Cash, cash equivalents and restricted cash at end of period (Note 7)	1,787	496
Noncash Investing and Financing Items [Abstract]
Change in accrued capital expenditures	(109)	(72)
U. S. Steel common stock issued for employee/non-employee director stock plans	18	25
Capital expenditures funded by finance lease borrowings	30	37
Export Credit Agreement (ECA) financing	$ 34	$ 0

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	1. Basis of Presentation and Significant Accounting Policies The year-end Consolidated Balance Sheet data was derived from audited statements but does not include all disclosures required for complete financial statements by accounting principles generally accepted in the United States of America (U.S. GAAP). The other information in these condensed financial statements is unaudited but, in the opinion of management, reflects all adjustments necessary for a fair statement of the results for the periods covered, including assessment of certain accounting matters using all available information including consideration of forecasted financial information in context with other information reasonably available to us. However, our future assessment of our current expectations, including consideration of the unknown future impacts of the COVID-19 pandemic, could result in material impacts to our consolidated financial statements in future reporting periods. All such adjustments are of a normal recurring nature unless disclosed otherwise. These condensed financial statements, including notes, have been prepared in accordance with the applicable rules of the Securities and Exchange Commission and do not include all of the information and disclosures required by U.S. GAAP for complete financial statements. Additional information is contained in the United States Steel Corporation Annual Report on Form 10-K for the fiscal year ended December 31, 2019, which should be read in conjunction with these condensed financial statements. Asset Impairment

New Accounting Standards

New Accounting Standards	9 Months Ended
	Sep. 30, 2020
Accounting Standards Update and Change in Accounting Principle [Abstract]
New Accounting Standards	2. New Accounting Standards In August 2020, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update 2020-06, Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (ASU 2020-06). ASU 2020-06 simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. ASU 2020-06 requires entities to provide expanded disclosures about the terms and features of convertible instruments and amends certain guidance in ASC 260 on the computation of EPS for convertible instruments and contracts on an entity’s own equity. ASU 2020-06 is effective for public companies for fiscal years beginning after December 15, 2021, and interim periods within those fiscal years, with early adoption of all amendments in the same period permitted. The Company is currently assessing the impact of adoption of the ASU. In March 2020, the FASB issued Accounting Standards Update 2020-04, Facilitation of the Effects of Reference Rate Reform on Financial Reporting (ASU 2020-04). ASU 2020-04 provides optional exceptions for applying generally accepted accounting principles to modifications of contracts, hedging relationships, and other transactions that reference LIBOR or another rate that will be discontinued by reference rate reform if certain criteria are met. The exceptions in ASU 2020-04 may be applied beginning in periods up to December 31, 2022. U. S. Steel is currently assessing the impact of the ASU but does not believe it will have a material impact on its Consolidated Financial Statements. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes (ASU 2019-12). ASU 2019-12 simplifies accounting for income taxes by removing certain exceptions from the general principles in Topic 740 including elimination of the exception to the incremental approach for intraperiod tax allocation when there is a loss from continuing operations and income or a gain from other items such as other comprehensive income. ASU 2019-12 also clarifies and amends certain guidance in Topic 740. ASU 2019-12 is effective for public companies for fiscal years beginning after December 15, 2020, including interim periods, with early adoption of all amendments in the same period permitted. U. S. Steel is currently assessing the impact of the ASU, but does not believe it will have a significant impact on its Consolidated Financial Statements.

Recently Adopted Accounting Sta

Recently Adopted Accounting Standards	9 Months Ended
	Sep. 30, 2020
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recently Adopted Accounting Standards	3. Recently Adopted Accounting Standard In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13), which adds an impairment model that is based on expected losses rather than incurred losses. Under ASU 2016-13, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. ASU 2016-13 was effective for public companies for fiscal years beginning after December 15, 2019 including interim reporting periods. U. S. Steel adopted this standard effective January 1, 2020. The impact of adoption was not material to the Condensed Consolidated Financial Statements. U. S. Steel's significant financial instruments which are valued at cost are trade receivables (receivables). U. S. Steel's receivables carry standard industry terms and are categorized in two receivable pools, U.S. and U. S. Steel Europe (USSE). Both pools use customer specific risk ratings based on customer financial metrics, past payment experience and other factors and qualitatively consider economic conditions to assess the level of allowance for doubtful accounts. USSE mitigates credit risk for approximately 75 percent of its receivables balance using credit insurance, letters of credit, bank guarantees, prepayments or other collateral. Below is a summary of the allowance for doubtful accounts for the segments. Additional reserve recorded in the nine month period ended September 30, 2020 primarily reflects uncertainty over near-term anticipated market conditions. (in millions) U.S. USSE Total Allowance Balance at December 31, 2019 $ 12 $ 16 $ 28 Additional reserve 5 1 6 Balance at September 30, 2020 $ 17 $ 17 $ 34

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segment Information	4. Segment Information U. S. Steel has three reportable segments: North American Flat-Rolled (Flat-Rolled), U. S. Steel Europe (USSE); and Tubular Products (Tubular). U. S. Steel's investment in Big River Steel and the results of our railroad and real estate businesses that do not constitute reportable segments are combined and disclosed in the Other Businesses category. The results of segment operations for the three months ended September 30, 2020 and 2019 are: (In millions) Three Months Ended September 30, 2020 Customer Intersegment Net (Loss) Earnings Earnings (loss) before interest and income taxes Flat-Rolled $ 1,728 $ 71 $ 1,799 $ (3) $ (159) USSE 495 1 496 — 13 Tubular 96 — 96 — (52) Total reportable segments 2,319 72 2,391 (3) (198) Other Businesses 21 23 44 (28) (13) Reconciling Items and Eliminations — (95) (95) — — Total $ 2,340 $ — $ 2,340 $ (31) $ (211) Three Months Ended September 30, 2019 Flat-Rolled $ 2,277 $ 86 $ 2,363 $ 30 $ 46 USSE 518 3 521 — (46) Tubular 262 1 263 1 (25) Total reportable segments 3,057 90 3,147 31 (25) Other Businesses 12 28 40 — 8 Reconciling Items and Eliminations — (118) (118) — (63) Total $ 3,069 $ — $ 3,069 $ 31 $ (80) The results of segment operations for the nine months ended September 30, 2020 and 2019 are: (In millions) Nine Months Ended September 30, 2020 Customer Intersegment Net (Loss) Earnings Earnings (loss) before interest and income taxes Flat-Rolled $ 5,199 $ 175 $ 5,374 $ (15) $ (523) USSE 1,403 3 1,406 — (27) Tubular 533 6 539 3 (147) Total reportable segments 7,135 184 7,319 (12) (697) Other Businesses 44 70 114 (66) (33) Reconciling Items and Eliminations — (254) (254) — (388) Total $ 7,179 $ — $ 7,179 $ (78) $ (1,118) Nine Months Ended September 30, 2019 Flat-Rolled $ 7,221 $ 250 $ 7,471 $ 63 $ 275 USSE 1,933 9 1,942 — (27) Tubular 921 4 925 5 (21) Total reportable segments 10,075 263 10,338 68 227 Other Businesses 38 88 126 — 26 Reconciling Items and Eliminations — (351) (351) — (107) Total $ 10,113 $ — $ 10,113 $ 68 $ 146 The following is a schedule of reconciling items to consolidated earnings before interest and income taxes: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2020 2019 2020 2019 Items not allocated to segments: Asset impairment charges (Notes 1 and 9) $ — $ — $ (263) $ — Restructuring and other charges (Note 20) — (54) (130) (54) Gain on previously held investment in UPI — — 25 — Tubular inventory impairment charge — — (24) — December 24, 2018 Clairton coke making facility fire — (9) 4 (53) Total reconciling items $ — $ (63) $ (388) $ (107)

Acquisition

Acquisition	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Acquisition	5. Acquisition On February 29, 2020, U. S. Steel purchased the remaining 50% ownership interest in USS-POSCO Industries (UPI) for $3 million, net of cash received of $2 million. There was an assumption of accounts payable owed to U. S. Steel for prior sales of steel substrate of $135 million associated with the purchase that is reflected as a reduction in receivables from related parties on the Company's Condensed Consolidated Balance Sheet. Using step acquisition accounting the Company increased the value of its previously held equity investment to its fair value of $5 million which resulted in a gain of approximately $25 million. The gain was recorded in gain on equity investee transactions in the Condensed Consolidated Statement of Operations. Receivables of $44 million, inventories of $96 million, accounts payable and accrued liabilities of $19 million, current portion of long-term debt of $55 million and payroll and employee benefits liabilities of $78 million were recorded with the acquisition. Property, plant and equipment of $97 million which included a fair value step-up of $47 million and an intangible asset of $54 million were also recorded on the Company's Condensed Consolidated Balance Sheet. The intangible asset, which will be amortized over ten years, arises from a land lease contract, under which a certain portion of payment owed to UPI is realized in the form of deductions from electricity costs.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue	6. Revenue Revenue is generated primarily from contracts to produce, ship and deliver steel products, and to a lesser extent, raw materials sales such as iron ore pellets and coke by-products and railroad services and real estate sales. Generally, U. S. Steel’s performance obligations are satisfied and revenue is recognized at a point in time, when title transfers to our customer for product shipped or services are provided. Revenues are recorded net of any sales incentives. Shipping and other transportation costs charged to customers are treated as fulfillment activities and are recorded in both revenue and cost of sales at the time control is transferred to the customer. Costs related to obtaining sales contracts are incidental and are expensed when incurred. Because customers are invoiced at the time title transfers and U. S. Steel’s right to consideration is unconditional at that time, U. S. Steel does not maintain contract asset balances. Additionally, U. S. Steel does not maintain contract liability balances, as performance obligations are satisfied prior to customer payment for product. U. S. Steel offers industry standard payment terms. The following tables disaggregate our revenue by product for each of the reportable business segments for the three months and nine months ended September 30, 2020 and 2019, respectively: Net Sales by Product (In millions): Three Months Ended September 30, 2020 Flat-Rolled USSE Tubular Other Businesses Total Semi-finished $ 5 $ — $ — $ — $ 5 Hot-rolled sheets 239 193 — — 432 Cold-rolled sheets 555 43 — — 598 Coated sheets 778 233 — — 1,011 Tubular products — 11 91 — 102 All Other (a) 151 15 5 21 192 Total $ 1,728 $ 495 $ 96 $ 21 $ 2,340 (a) Consists primarily of sales of raw materials and coke making by-products. Three Months Ended September 30, 2019 Flat-Rolled USSE Tubular Other Businesses Total Semi-finished $ 69 $ 2 $ — $ — $ 71 Hot-rolled sheets 537 199 — — 736 Cold-rolled sheets 627 59 — — 686 Coated sheets 765 231 — — 996 Tubular products — 11 257 — 268 All Other (a) 279 16 5 12 312 Total $ 2,277 $ 518 $ 262 $ 12 $ 3,069 (a) Consists primarily of sales of raw materials and coke making by-products. Nine Months Ended September 30, 2020 Flat-Rolled USSE Tubular Other Businesses Total Semi-finished $ 63 $ 2 $ — $ — $ 65 Hot-rolled sheets 980 544 — — 1,524 Cold-rolled sheets 1,495 114 — — 1,609 Coated sheets 2,202 664 — — 2,866 Tubular products — 31 520 — 551 All Other (a) 459 48 13 44 564 Total $ 5,199 $ 1,403 $ 533 $ 44 $ 7,179 (a) Consists primarily of sales of raw materials and coke making by-products. Nine Months Ended September 30, 2019 Flat-Rolled USSE Tubular Other Businesses Total Semi-finished $ 278 $ 11 $ — $ — $ 289 Hot-rolled sheets 1,982 818 — — 2,800 Cold-rolled sheets 1,931 229 — — 2,160 Coated sheets 2,309 779 — — 3,088 Tubular products — 31 903 — 934 All Other (a) 721 65 18 38 842 Total $ 7,221 $ 1,933 $ 921 $ 38 $ 10,113 (a) Consists primarily of sales of raw materials and coke making by-products.

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	9 Months Ended
	Sep. 30, 2020
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash, Cash Equivalents and Restricted Cash	7. Cash, Cash Equivalents and Restricted Cash The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within U. S. Steel's Condensed Consolidated Balance Sheets that sum to the total of the same amounts shown in the Condensed Consolidated Statement of Cash Flows: (In millions) September 30, 2020 September 30, 2019 Cash and cash equivalents $ 1,696 $ 476 Restricted cash in other current assets 2 — Restricted cash in other noncurrent assets 89 20 Total cash, cash equivalents and restricted cash $ 1,787 $ 496 Amounts included in restricted cash represent cash balances which are legally or contractually restricted, primarily for electric arc furnace construction, environmental capital expenditure projects and insurance purposes.

Inventories

Inventories	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Inventories	8. Inventories The LIFO method is the predominant method of inventory costing in the United States. The FIFO method is the predominant inventory costing method in Europe. At September 30, 2020 and December 31, 2019, the LIFO method accounted for 72 percent and 75 percent of total inventory values, respectively. (In millions) September 30, 2020 December 31, 2019 Raw materials $ 465 $ 628 Semi-finished products 557 720 Finished products 320 376 Supplies and sundry items 56 61 Total $ 1,398 $ 1,785 Current acquisition costs were estimated to exceed the above inventory values by $802 million and $735 million at September 30, 2020 and December 31, 2019, respectively. As a result of the liquidation of LIFO inventories, cost of sales decreased and earnings before interest and income taxes increased by $11 million and $5 million for the three and nine months ended September 30, 2020, respectively. Cost of sales decreased and earnings before interest and income taxes increased by $12 million and $5 million for the three and nine months ended September 30, 2019, respectively, as a result of liquidation of LIFO inventories. Inventory includes $37 million and $40 million of land held for residential/commercial development as of September 30, 2020 and December 31, 2019, respectively.

Intangible Assets

Intangible Assets	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	9. Intangible Assets Intangible assets that are being amortized on a straight-line basis over their estimated useful lives are detailed below: As of September 30, 2020 As of December 31, 2019 (In millions) Useful Gross Accumulated Impairment (a) Accumulated Net Gross Accumulated Net Customer relationships 22 Years $ 132 $ 55 $ 77 $ — $ 132 $ 76 $ 56 Patents 10-15 Years 22 7 10 5 22 8 14 Energy Contract 10 Years 54 — 3 51 — — — Other 4-20 Years 14 5 9 — 14 9 5 Total amortizable intangible assets $ 222 $ 67 $ 99 $ 56 $ 168 $ 93 $ 75 (a) The impairment charge was the result of the quantitative impairment analysis of the welded tubular asset group for the period ended March 31, 2020. See Note 1 for further details. The estimated amortization expense for the remainder of 2020 is $2 million. We expect approximately $6 million in annual amortization expense through 2025 and approximately $24 million in remaining amortization expense thereafter. The carrying amount of acquired water rights with indefinite lives as of September 30, 2020 and December 31, 2019 totaled $75 million.

Pensions and Other Benefits

Pensions and Other Benefits	9 Months Ended
	Sep. 30, 2020
Retirement Benefits [Abstract]
Pensions and Other Benefits	10. Pensions and Other Benefits The following table reflects the components of net periodic benefit cost for the three months ended September 30, 2020 and 2019: Pension Other (In millions) 2020 2019 2020 2019 Service cost $ 13 $ 11 $ 3 $ 4 Interest cost 49 59 16 22 Expected return on plan assets (84) (81) (20) (19) Amortization of prior service cost — — (1) 8 Amortization of actuarial net loss (gain) 36 33 (4) — Net periodic benefit cost, excluding below 14 22 (6) 15 Multiemployer plans 19 20 — — Settlement, termination and curtailment losses (a) 2 3 — — Net periodic benefit cost $ 35 $ 45 $ (6) $ 15 (a) During the three months ended September 30, 2020 and 2019, the pension plan incurred settlement charges of approximately $2 million and $3 million, respectively, due to lump sum payments for certain individuals. The following table reflects the components of net periodic benefit cost for the nine months ended September 30, 2020 and 2019: Pension Other (In millions) 2020 2019 2020 2019 Service cost $ 38 $ 33 $ 9 $ 10 Interest cost 145 178 48 68 Expected return on plan assets (249) (243) (60) (59) Amortization of prior service cost 1 1 (5) 22 Amortization of actuarial net loss (gain) 108 99 (12) 2 Net periodic benefit cost, excluding below 43 68 (20) 43 Multiemployer plans 58 57 — — Settlement, termination and curtailment losses (a) 10 3 — — Net periodic benefit cost $ 111 $ 128 $ (20) $ 43 (a) During the nine months ended September 30, 2020 and 2019, the pension plan incurred settlement and special termination charges of approximately $10 million and $3 million, respectively, due to workforce restructuring and lump sum payments made to certain individuals. Employer Contributions During the first nine months of 2020, U. S. Steel made cash payments of $57 million to the Steelworkers’ Pension Trust and $6 million of pension payments not funded by trusts. During the first nine months of 2020, cash payments of $37 million were made for other postretirement benefit payments not funded by trusts.

Stock-Based Compensation Plans

Stock-Based Compensation Plans	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation Plans	11. Stock-Based Compensation Plans U. S. Steel has outstanding stock-based compensation awards that were granted by the Compensation & Organization Committee of the Board of Directors (the Committee) under the 2005 Stock Incentive Plan (the 2005 Plan) and the 2016 Omnibus Incentive Compensation Plan, as amended and restated (the Omnibus Plan). The Company's stockholders approved the Omnibus Plan and authorized the Company to issue up to 18,200,000 shares of U. S. Steel common stock under the Omnibus Plan. While the awards that were previously granted under the 2005 Plan remain outstanding, all future awards will be granted under the Omnibus Plan. As of September 30, 2020, there were 5,995,783 shares available for future grants under the Omnibus Plan. Recent grants of stock-based compensation consist of restricted stock units, total stockholder return (TSR) performance awards and return on capital employed (ROCE) performance awards. Shares of common stock under the Omnibus Plan are issued from authorized, but unissued stock. The following table is a summary of the awards made under the Omnibus Plan during the first nine months of 2020 and 2019. 2020 2019 Grant Details Shares (a) Fair Value (b) Shares (a) Fair Value (b) Restricted Stock Units 2,640,690 $ 8.82 1,005,500 $ 23.76 Performance Awards (c) TSR 671,390 $ 8.19 210,520 $ 29.22 ROCE (d) — $ — 527,470 $ 23.90 (a) The share amounts shown in this table do not reflect an adjustment for estimated forfeitures. (b) Represents the per share weighted-average for all grants during the period. (c) The number of performance awards shown represents the target share grant of the award. (d) The ROCE awards granted in 2020 are not shown in the table because they were granted in cash. U. S. Steel recognized pretax stock-based compensation expense in the amount of $8 million and $10 million in the three-month periods ended September 30, 2020 and 2019, respectively, and $20 million and $30 million in the first nine months of 2020 and 2019, respectively. As of September 30, 2020, total future compensation expense related to nonvested stock-based compensation arrangements was $16 million, and the weighted average period over which this expense is expected to be recognized is approximately 16 months. Restricted stock units awarded as part of annual grants generally vest ratably over three years. Their fair value is the market price of the underlying common stock on the date of grant. Restricted stock units granted in connection with new-hire or retention grants generally cliff vest three years from the date of the grant. TSR performance awards may vest at varying levels at the end of a three-year performance period if U. S. Steel's total stockholder return compared to the total stockholder return of a peer group of companies meets specified performance criteria with each year in the three-year performance period weighted at 20 percent and the full three-year performance weighted at 40 percent. TSR performance awards can vest at between zero and 200 percent of the target award. The fair value of the TSR performance awards is calculated using a Monte-Carlo simulation. ROCE performance awards may vest at the end of a three-year performance period contingent upon meeting the specified ROCE performance. ROCE performance awards can vest at between zero and 200 percent of the target award. The fair value of the ROCE performance awards is the average market price of the underlying common stock on the date of grant. For further details about our stock-based compensation incentive plans and stock awards see Note 15 of the United States Steel Corporation Annual Report on Form 10-K for the fiscal year-ended December 31, 2019.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes Tax provision For the nine months ended September 30, 2020 and 2019, the Company recorded a tax benefit of $48 million and $43 million, respectively. The tax benefit for the first nine months of 2020 was based on an estimated annual effective rate, which requires management to make its best estimate of annual pretax income or loss. The 2020 tax benefit includes a $39 million discrete benefit related to recording a loss from continuing operations and income from other comprehensive income categories and expense of $13 million for an updated estimate to tax reserves related to an unrecognized tax benefit. Due to the full valuation allowance on our domestic deferred tax assets, the tax benefit in 2020 does not reflect any additional tax benefit for domestic pretax losses. In 2019, the tax provision reflects a benefit for percentage depletion in excess of cost depletion from iron ore that we produce and consume or sell. During the year, management regularly updates forecasted annual pretax results for the various countries in which we operate based on changes in factors such as prices, shipments, product mix, plant operating performance and cost estimates. To the extent that actual 2020 pretax results for foreign income or loss vary from estimates applied herein, the actual tax provision or benefit recognized in 2020 could be materially different from the forecasted amount used to estimate the tax benefit for the nine months ended September 30, 2020.

Earnings and Dividends Per Comm

Earnings and Dividends Per Common Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Earnings and Dividends Per Common Share	13. Earnings and Dividends Per Common Share (Loss) Earnings Per Share Attributable to United States Steel Corporation Stockholders The effect of dilutive securities on weighted average common shares outstanding included in the calculation of diluted earnings per common share for the three and nine months ended September 30, 2020 and September 30, 2019 were as follows. Three Months Ended September 30, Nine Months Ended September 30, (Dollars in millions, except per share amounts) 2020 2019 2020 2019 (Loss) earnings attributable to United States Steel Corporation stockholders $ (234) $ (84) $ (1,214) $ 38 Weighted-average shares outstanding (in thousands): Basic 220,402 170,801 188,766 171,882 Effect of Senior Convertible Notes — — — — Effect of stock options, restricted stock units and performance awards — — — 629 Adjusted weighted-average shares outstanding, diluted 220,402 170,801 188,766 172,511 Basic (loss) earnings per common share $ (1.06) $ (0.49) $ (6.43) $ 0.22 Diluted (loss) earnings per common share $ (1.06) $ (0.49) $ (6.43) $ 0.22 Excluded from the computation of diluted (loss) earnings per common share due to their anti-dilutive effect were 5.7 million and 5.5 million outstanding securities granted under the Omnibus Plan for the three and nine months ended September 30, 2020, respectively, and 4.3 million and 3.3 million outstanding securities granted under the Omnibus Plan for the three and nine months ended September 30, 2019. Dividends Paid Per Share The dividend for each of the first, second and third quarters of 2020 and 2019 was one cent and five cents per common share, respectively.

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	14. Derivative Instruments U. S. Steel uses foreign exchange forward sales contracts to exchange euros for U.S. dollars (USD) and USD for Canadian dollars (foreign exchange forwards) with maturities no longer than 12 months to mitigate the risk of foreign currency exchange rate fluctuations and manage our foreign currency requirements. Financial swaps are used to protect from commodity price risk associated with purchases of natural gas, zinc, tin and electricity (commodity purchase swaps). We use cash flow hedge accounting for our foreign exchange forwards and for our U.S. commodity purchase swaps for natural gas, zinc and tin and use mark-to-market accounting for commodity purchase swaps used in our European operations and for electricity commodity purchase swaps. The maximum derivative contract duration for commodity purchase swaps where hedge accounting was elected and was not elected is 15 months and 28 months, respectively. For further details about our derivative instruments see Note 16 of the United States Steel Corporation Annual Report on Form 10-K for the fiscal year-ended December 31, 2019. The table below shows the outstanding swap quantities used to hedge forecasted purchases and sales as of September 30, 2020 and September 30, 2019: Hedge Contracts Classification September 30, 2020 September 30, 2019 Natural gas (in mmbtus) Commodity purchase swaps 34,222,000 56,873,000 Tin (in metric tons) Commodity purchase swaps 787 530 Zinc (in metric tons) Commodity purchase swaps 8,148 14,561 Electricity (in megawatt hours) Commodity purchase swaps 847,680 — Foreign currency (in millions of euros) Foreign exchange forwards € 240 € 316 Foreign currency (in millions of CAD) Foreign exchange forwards $ 8 $ 33 There were $8 million and $1 million in accounts receivable and $13 million and $18 million in accounts payable recorded for derivatives designated as hedging instruments as of September 30, 2020 and December 31, 2019, respectively. Amounts recorded in long-term asset and long-term liability accounts for derivatives designated as hedging instruments and amounts recorded in the Condensed Consolidated Balance Sheet for derivatives not designated as hedging instruments were not significant as of September 30, 2020 and December 31, 2019. The table below summarizes the effect of hedge accounting on AOCI and amounts reclassified from AOCI into earnings for the three and nine months ended September 30, 2020 and 2019: Gain (Loss) on Derivatives in AOCI Amount of Gain (Loss) Recognized in Income (In millions) Three Months Ended September 30, 2020 Three Months Ended September 30, 2019 Location of Reclassification from AOCI (a) Three Months Ended September 30, 2020 Three Months Ended September 30, 2019 Commodity purchase swaps 19 (6) Cost of sales (c) (6) (4) Foreign exchange forwards (b) (9) 3 Cost of sales (3) — (a) The earnings impact of hedging instruments substantially offsets the earnings impact of the related hedged items since ineffectiveness is less than $1 million. (b) U. S. Steel has elected hedge accounting prospectively for European foreign exchange forwards on July 1, 2019. (c) Costs for commodity purchase swaps are recognized in cost of sales as products are sold. Gain (Loss) on Derivatives in AOCI Amount of Gain (Loss) Recognized in Income (In millions) Nine Months Ended September 30, 2020 Nine Months Ended September 30, 2019 Location of Reclassification from AOCI (a) Nine Months Ended September 30, 2020 Nine Months Ended September 30, 2019 Commodity purchase swaps 30 (2) Cost of sales (c) (26) (14) Foreign exchange forwards (b) (8) 4 Cost of sales (2) — (a) The earnings impact of hedging instruments substantially offsets the earnings impact of the related hedged items since ineffectiveness is less than $1 million. (b) U. S. Steel has elected hedge accounting prospectively for European foreign exchange forwards on July 1, 2019. (c) Costs for commodity purchase swaps are recognized in cost of sales as products are sold. At current contract values, $5 million currently in AOCI as of September 30, 2020 will be recognized as an increase in cost of sales over the next year. The amount of gain (loss) recognized in income for foreign exchange forwards where hedge accounting was not elected was not material for the three and nine month periods ended September 30, 2020 and was $11 million and $18 million for the three and nine month periods ended September 30, 2019, respectively. These impacts were recognized in other financial costs in our Condensed Consolidated Statement of Operations. Earnings impacts for commodity purchase swaps were not material for the three month and nine month periods ended September 30, 2020 and September 30, 2019.

Debt

Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt	15. Debt (In millions) Interest Maturity September 30, 2020 December 31, 2019 2037 Senior Notes 6.650 2037 $ 350 $ 350 2026 Senior Notes 6.250 2026 650 650 2026 Senior Convertible Notes 5.000 2026 350 350 2025 Senior Notes 6.875 2025 750 750 2025 Senior Secured Notes 12.000 2025 1,056 — Export-Import Credit Agreement Variable 2021 250 — Environmental Revenue Bonds 4.875 - 6.750 2024 - 2049 620 620 Fairfield Caster Lease 2022 17 18 Other finance leases and all other obligations 2020 - 2029 69 48 ECA Credit Agreement Variable 2031 104 — Credit Facility Agreement, $2.0 billion Variable 2024 500 600 UPI Amended Credit Facility Variable 2020 — — USSK Credit Agreement Variable 2023 410 393 USSK Credit Facilities Variable 2021 — — Total Debt 5,126 3,779 Less unamortized discount and debt issuance costs 236 138 Less short-term debt and long-term debt due within one year 262 14 Long-term debt $ 4,628 $ 3,627 To the extent not otherwise discussed below, information concerning the senior notes and other listed obligations can be found in Note 17 of the audited financial statements in the United States Steel Corporation Annual Report on Form 10-K for the fiscal year ended December 31, 2019. Export-Import Credit Agreement On September 30, 2020, U. S. Steel and its subsidiary, United States Steel International, Inc., as the borrowers, entered into an Export-Import Transaction Specific Loan and Security Agreement (Export-Import Credit Agreement) with the lenders party thereto from time to time and PNC Bank, National Association (PNC), as agent for the lenders, under which it borrowed approximately $240 million, net of transaction fees of approximately $10 million. The Export-Import Credit Agreement provides for up to $250 million of term loans, which mature on August 30, 2021, unless sooner terminated or extended by the borrowers to July 30, 2022. The maturity of the term loans under the Export-Import Credit Agreement may be extended only if the loan facility continues to be eligible for coverage (at a 95% level) under the Ex-Im Guarantee (as defined in the Export-Import Credit Agreement) and each lender consents to such extension. Interest on the term loans will accrue at a contract rate of 2.50% plus the applicable LIBOR rate. The obligations under the Export-Import Credit Agreement are secured by receivables (collateral) under certain iron ore pellet export contracts. The Export-Import Credit Agreement permits voluntary prepayments and requires mandatory prepayments with net cash proceeds of dispositions of collateral. The Export-Import Credit Agreement also contains certain customary covenants and restrictions, including restrictions on sale of assets, restrictions on incurring liens upon collateral and a requirement that the borrowers comply with the Ex-Im Borrower Agreement (entered into on September 30, 2020 by the borrowers in favor of Ex-Im Bank, the lenders and PNC, as agent for the lenders). 2025 Senior Secured Notes On May 29, 2020, U. S. Steel issued $1.056 billion aggregate principal amount of 12.000% Senior Secured Notes due June 1, 2025 (2025 Senior Secured Notes) in a 144A private transaction exempt from the registration requirements of the Securities Act of 1933, as amended. The notes were issued at a price equal to 94.665% of their face value. U. S. Steel received net proceeds from the offering of approximately $977 million after fees of approximately $23 million related to underwriting and third party expenses. The notes will pay interest semi-annually in arrears on June 1 and December 1 of each year, beginning on December 1, 2020. The notes are fully and unconditionally guaranteed on a senior secured basis by all of our existing and future direct and indirect material domestic subsidiaries (other than certain subsidiaries excluded in the indenture). The notes and notes guarantees are secured by first priority-liens, subject to permitted liens, on substantially all of U. S. Steel’s domestic assets, other than certain excluded assets per the terms of the notes indenture and exclusive of the collateral required under the Credit Facility Agreement. The Company may redeem the 2025 Senior Secured Notes, in whole or part, at its option on or after June 1, 2022 at the redemption price for such notes as a percentage of the principal amount, plus accrued and unpaid interest to, but excluding, the redemption date, if redeemed during the twelve-month period beginning on June 1st of each of the years indicated below. Year Redemption Price 2022 106 % 2023 103 % 2024 and thereafter 100 % Prior to June 1, 2022, the Company may redeem up to 35% of the original aggregate principal amount of the 2025 Senior Secured Notes with the net cash proceeds of one or more equity offerings for a price of 112.000% of principal amount of the 2025 Senior Secured Notes plus accrued and unpaid interest, if any, to the applicable date of redemption. Upon the occurrence of certain assets sales, we are required to apply asset sale proceeds towards investments in assets that constitute Notes collateral. If all asset sale proceeds are not invested within one year, or such longer period as permitted by the indenture, the Company may be required to offer to repurchase the 2025 Senior Secured Notes up to an amount of asset sale proceeds that remain uninvested at a price of 100% of the principal amount thereof, plus accrued and unpaid interest if any to the date of such purchase. The indenture pursuant to which the 2025 Senior Secured Notes were issued contains limitations on the incurrence of additional debt secured by liens and additional customary covenants and other obligations. Export Credit Agreement Funding of U. S. Steel’s vendor supported Export Credit Agreement (ECA) occurred on February 19, 2020. U. S. Steel had borrowed $104 million under the ECA as of September 30, 2020. Loan repayments start six months after the starting point of credit as defined in the loan agreement with a total repayment term up to eight years. Loan availability and repayment terms are subject to certain customary covenants and events of default. The purpose of the ECA is to finance equipment purchased for the endless casting and rolling facility at the Mon Valley Works facility in Braddock, Pennsylvania. Credit Facility Agreement As of September 30, 2020, there was $500 million drawn under the $2.0 billion Fifth Amended and Restated Credit Facility Agreement (Credit Facility Agreement). U. S. Steel must maintain a fixed charge coverage ratio of at least 1.00 to 1.00 for the most recent four consecutive quarters when availability under the Credit Facility Agreement is less than the greater of 10 percent of the total aggregate commitments and $200 million. Based on the most recent four quarters as of September 30, 2020, the Company would not have met the fixed charge coverage ratio test; therefore, the amount available to the Company under this facility is effectively reduced by $200 million. In addition, since the value of our inventory and trade accounts receivable less specified reserves calculated in accordance with the Credit Facility Agreement do not support the full amount of the facility at September 30, 2020, the amount available to the Company under this facility was further reduced by $294 million. The availability under the Credit Facility Agreement was $1.006 billion as of September 30, 2020. The Credit Facility Agreement provides for borrowings at interest rates based on defined, short-term market rates plus a spread based on availability and includes other customary terms and conditions including restrictions on our ability to create certain liens and to consolidate, merge or transfer all, or substantially all, of our assets. The Credit Facility Agreement expires in October 2024. Maturity may be accelerated 91 days prior to the stated maturity of any outstanding senior debt if excess cash and credit facility availability do not meet the liquidity conditions set forth in the Credit Facility Agreement. Borrowings are secured by liens on certain North American inventory and trade accounts receivable. Availability under this facility may be impacted by additional footprint decisions that are made to the extent the value of the collateral pool of inventory and accounts receivable that support our borrowing availability are reduced. The Credit Facility Agreement has customary representations and warranties including, as a condition to borrowing, that all such representations and warranties are true and correct, in all material respects, on the date of the borrowing, including representations as to no material adverse change in our business or financial condition that is not disclosed in our last published financial results. The facility also has customary defaults, including a cross-default to material indebtedness of U. S. Steel and our subsidiaries. On September 30, 2020, U. S. Steel entered into an Amendment No. 1 (the “Amendment”) to the Credit Facility Agreement with the Lenders party thereto and JPMorgan Chase Bank, N.A., as Administrative Agent and Collateral Agent, to permit U. S. Steel and United States Steel International Inc. to enter into, and grant the applicable collateral pursuant to, the Export-Import Credit Agreement. U. S. Steel Košice ( USSK) Credit Facilities At September 30, 2020, USSK had borrowings of €350 million (approximately $410 million) under its €460 million (approximately $539 million) revolving credit facility (USSK Credit Agreement). The USSK Credit Agreement expires in September 2023. The USSK Credit Agreement contains certain USSK specific financial covenants including a minimum stockholders' equity to assets ratio and net debt to EBITDA ratio. The covenants are measured semi-annually at June and December each year for the period covering the last twelve calendar months, with the first net debt to EBITDA measurement occurring at June 2021. USSK must maintain a net debt to EBITDA ratio of less than 6.5 as of June 30, 2021 and 3.5 for semi-annual measurements starting December 31, 2021. If covenant compliance requirements are not met and the covenants are not amended or waived, noncompliance may result in an event of default, in which case USSK may not draw upon the facility, and the majority lenders, as defined in the USSK Credit Agreement, may cancel any and all commitments, and/or accelerate full repayment of any or all amounts outstanding under the USSK Credit Agreement. An event of default under the USSK Credit Agreement could also result in an event of default under the Credit Facility Agreement. The USSK Credit Agreement contains customary representations and warranties, terms and conditions, including, as a condition to borrowing, that it met certain financial covenants since the last measurement date, and that all such representations and warranties are true and correct, in all material respects, on the date of the borrowing, and representations as to no material adverse change in our business or financial condition since December 31, 2017. The USSK Credit Facility Agreement also contains customary events of default, including a cross-default upon acceleration of material indebtedness of USSK and its subsidiaries. At September 30, 2020, USSK had no borrowings under its €20 million and €10 million credit facilities (collectively, approximately $35 million) and the availability was approximately $33 million due to approximately $2 million of customs and other guarantees outstanding. Each of these facilities bear interest at the applicable inter-bank offer rate plus a margin and contain customary terms and conditions. USS-POSCO Industries Credit Facility The USS-POSCO Industries (UPI) Amended Credit Facility agreement was terminated on July 17, 2020 and the outstanding borrowings were repaid using cash on hand. Upon termination of the UPI Amended Credit Facility, UPI was added as a subsidiary guarantor to the Credit Facility Agreement, which increased the amount of collateral and availability under the Credit Facility Agreement. Change in control event

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	16. Fair Value of Financial Instruments The carrying value of cash and cash equivalents, current accounts and notes receivable, accounts payable, bank checks outstanding, and accrued interest included in the Condensed Consolidated Balance Sheet approximate fair value. See Note 14 for disclosure of U. S. Steel’s derivative instruments, which are accounted for at fair value on a recurring basis. The net change in fair value of the options related to our purchase of the equity investment in Big River Steel during the nine months ended September 30, 2020 resulted in an $40 million decrease to net interest and other financial costs. The financial impact was primarily due to an increase in equity value. The following table shows the change in fair value by option for the nine month period ended September 30, 2020. (In millions) Balance Sheet Location Fair Value asset/(liability) Fair Value Fair Value asset/(liability) U. S. Steel Call Option Investments and Long-Term Receivables $ 166 $ (96) $ 70 Class B Common Deferred credits and other noncurrent liabilities $ (192) $ 135 $ (57) Class B Common Deferred credits and other noncurrent liabilities $ (2) $ 1 $ (1) Net Mark to Market Impact $ 40 The fair value of the U. S. Steel Call Option and Class B Common Put Option are most significantly impacted by certain unobservable inputs including Big River Steel’s equity value and volatility. The Class B Common Put Option is also significantly impacted by U. S. Steel’s credit spread. A significant factor in determining equity value is the discounted forecasted cash flows of Big River Steel. Forecasted cash flows are primarily impacted by the forecasted market price of steel and metallic inputs as well as the expected timing of significant capital expenditures. The most recent updated forecast indicated an increase in the equity value which was the primary factor that led to a favorable mark-to-market adjustment of $34 million that is reflected in other financial benefits in the Condensed Consolidated Statement of Operations for the three month period ended September 30, 2020. See Note 20 of the audited financial statements in the United States Steel Corporation Annual Report on Form 10-K for the fiscal year ended December 31, 2019 for further details. Stelco Option for Minntac Mine Interest On April 30, 2020 (the Effective Date), the Company entered into an Option Agreement with Stelco, Inc. (Stelco), that grants Stelco the option to purchase a 25 percent interest (the Option Interest) in a to-be-formed entity (the Joint Venture) that will own the Company’s current iron ore mine located in Mt. Iron, Minnesota (the Minntac Mine). As consideration for the Option, Stelco will pay the Company an aggregate amount of $100 million in five $20 million installments, which began on the Effective Date and will end on December 31, 2020. In the event Stelco exercises the option, Stelco will contribute an additional $500 million to the Joint Venture, which amount shall be remitted solely to U. S. Steel in the form of a one-time special distribution, and the parties will engage in good faith negotiations to finalize the master agreement (pursuant to which Stelco will acquire the Option Interest) and the limited liability company agreement of the Joint Venture. As of September 30, 2020, Stelco has made installment payments totaling $60 million which are recorded net of transaction costs in noncontrolling interest in the Condensed Consolidated Balance Sheet. The following table summarizes U. S. Steel’s financial liabilities that were not carried at fair value at September 30, 2020 and December 31, 2019. The fair value of long-term debt was determined using Level 2 inputs. September 30, 2020 December 31, 2019 (In millions) Fair Carrying Fair Carrying Financial liabilities: Short-term and long-term debt (a) $ 4,448 $ 4,804 $ 3,576 $ 3,575 (a) Excludes finance lease obligations.

Statement of Changes in Stockho

Statement of Changes in Stockholders' Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Statement of Changes in Stockholders' Equity	17. Statement of Changes in Stockholders’ Equity The following table reflects the first nine months of 2020 and 2019 reconciliation of the carrying amount of total equity, equity attributable to U. S. Steel and equity attributable to noncontrolling interests: Nine Months Ended September 30, 2020 (In millions) Total Retained Earnings (Accumulated Deficit) Accumulated Common Treasury Paid-in Non- Balance at beginning of year $ 4,093 $ 544 $ (478) $ 179 $ (173) $ 4,020 $ 1 Comprehensive income (loss): Net loss (391) (391) — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 52 — 52 — — — — Currency translation adjustment (23) — (23) — — — — Derivative financial instruments (5) — (5) Employee stock plans 2 — — — (2) 4 — Dividends paid on common stock (2) (2) — — — — — Balance at March 31, 2020 $ 3,726 $ 151 $ (454) $ 179 $ (175) $ 4,024 $ 1 Comprehensive income (loss): Net loss (589) (589) — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 29 — 29 — — — — Currency translation adjustment 20 — 20 — — — — Derivative financial instruments 15 — 15 — — — — Employee stock plans 8 — — — — 8 — Common Stock Issued 410 — — 50 — 360 — Dividends paid on common stock (1) — — — — (1) — Stelco Option Agreement 37 — — — — — 37 Other (1) — — — — — (1) Balance at June 30, 2020 $ 3,654 $ (438) $ (390) $ 229 $ (175) $ 4,391 $ 37 Comprehensive income (loss): Net loss (234) (234) — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 16 — 16 — — — — Currency translation adjustment 34 — 34 — — — — Derivative financial instruments 8 — 8 — — — — Employee stock plans 10 — — — — 10 — Dividends paid on common stock (3) — — — — (3) — Stelco Option Agreement 18 — — — — 18 Other 1 1 — — — — — Balance at September 30, 2020 $ 3,504 $ (671) $ (332) $ 229 $ (175) $ 4,398 $ 55 Nine Months Ended September 30, 2019 (In millions) Total Retained Earnings Accumulated Common Treasury Paid-in Non- Balance at beginning of year $ 4,203 $ 1,212 $ (1,026) $ 177 $ (78) $ 3,917 $ 1 Comprehensive income (loss): Net earnings 54 54 — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 32 — 32 — — — — Currency translation adjustment (17) — (17) — — — — Derivative financial instruments 15 15 Employee stock plans 2 — — 1 (6) 7 — Common stock repurchased (42) — — — (42) — — Dividends paid on common stock (9) (9) — — — — — Cumulative effect upon adoption of lease accounting standard (2) (2) — — — — — Balance at March 31, 2019 $ 4,236 $ 1,255 $ (996) $ 178 $ (126) $ 3,924 $ 1 Comprehensive income (loss): Net earnings 68 68 — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 32 — 32 — — — — Currency translation adjustment 12 — 12 — — — — Derivative financial instruments (11) — (11) — — — — Employee stock plans 12 — — 1 (1) 12 — Common stock repurchased (28) — — — (28) — — Dividends paid on common stock (9) (9) — — — — — Balance at June 30, 2019 $ 4,312 $ 1,314 $ (963) $ 179 $ (155) $ 3,936 $ 1 Comprehensive income (loss): Net loss (84) (84) — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 30 — 30 — — — — Currency translation adjustment (40) — (40) — — — — Derivative financial instruments (2) — (2) — — — — Employee stock plans 11 — — — — 11 — Common stock repurchased (18) — — — (18) — — Dividends paid on common stock (8) (8) — — — — — Other (1) (1) — — — — — Balance at September 30, 2019 $ 4,200 $ 1,221 $ (975) $ 179 $ (173) $ 3,947 $ 1

Reclassifications from Accumula

Reclassifications from Accumulated Other Comprehensive Income (AOCI)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Reclassifications from Accumulated Other Comprehensive Income (AOCI)	18. Reclassifications from Accumulated Other Comprehensive Income (AOCI) (In millions) Pension and Foreign Unrealized Gain (Loss) on Derivatives Total Balance at December 31, 2019 $ (843) $ 381 $ (16) $ (478) Other comprehensive income (loss) before reclassifications 6 31 (6) 31 Amounts reclassified from AOCI (a) 91 — 24 115 Net current-period other comprehensive income (loss) 97 31 18 146 Balance at September 30, 2020 $ (746) $ 412 $ 2 $ (332) Balance at December 31, 2018 $ (1,416) $ 403 $ (13) $ (1,026) Other comprehensive (loss) income before reclassifications (3) (45) (12) (60) Amounts reclassified from AOCI (a) 97 — 14 111 Net current-period other comprehensive income (loss) 94 (45) 2 51 Balance at September 30, 2019 $ (1,322) $ 358 $ (11) $ (975) (a) See table below for further details. Amount reclassified from AOCI (a) Three Months Ended September 30, Nine Months Ended September 30, Details about AOCI components (in millions) 2020 2019 2020 2019 Amortization of pension and other benefit items Prior service costs (a) $ (1) $ 8 $ (4) $ 23 Actuarial losses (a) 32 33 96 101 Settlement, termination and curtailment losses (a) 2 3 2 3 UPI Purchase Accounting Adjustment — — 23 — Total pensions and other benefits items 33 44 117 127 Derivative reclassifications to Condensed Consolidated Statements of Operations 6 5 28 19 Total before tax 39 49 145 146 Tax provision (15) (12) (30) (35) Net of tax $ 24 $ 37 $ 115 $ 111 (a) These AOCI components are included in the computation of net periodic benefit cost (see Note 10 for additional details).

Transactions with Related Parti

Transactions with Related Parties	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Transactions with Related Parties	19. Transactions with Related Parties Related party sales and service transactions are primarily related to equity investees and were $268 million and $367 million for the three months ended September 30, 2020 and 2019, respectively and $710 million and $1,112 million for the nine months ended September 30, 2020 and 2019, respectively. The transaction to purchase UPI included the assumption of $135 million of accounts payable owed to U. S. Steel for prior sales of steel substrate to UPI. This amount is reflected as a reduction in receivables from related parties on the Company's Condensed Consolidated Balance Sheet as both the corresponding receivable and payable amounts between U. S. Steel and UPI are eliminated in consolidation upon acquisition. See Note 5 to the Condensed Consolidated Financial Statements for further details. Purchases from related parties for outside processing services provided by equity investees amounted to $9 million and $7 million for the three months ended September 30, 2020 and 2019, respectively and $47 million and $23 million for the nine months ended September 30, 2020 and 2019, respectively. Purchases of iron ore pellets from related parties amounted to $19 million and $27 million for the three months ended September 30, 2020 and 2019, respectively, and $53 million and $78 million for the nine months ended September 30, 2020 and 2019. Accounts payable to related parties include balances due to PRO-TEC Coating Company, LLC (PRO-TEC) of $109 million and $82 million at September 30, 2020 and December 31, 2019, respectively for invoicing and receivables collection services provided by U. S. Steel on PRO-TEC's behalf. U. S. Steel, as PRO-TEC’s exclusive sales agent, is

Restructuring and Other Charges

Restructuring and Other Charges	9 Months Ended
	Sep. 30, 2020
Restructuring and Related Activities [Abstract]
Restructuring and Other Charges	20. Restructuring and Other Charges During the nine months ended September 30, 2020, the Company recorded restructuring and other charges of $130 million, which consists of charges of $72 million for the indefinite idling of our Keetac mining operations and a significant portion of Great Lakes Works, $13 million for the indefinite idling of Lorain Tubular Operations and Lone Star Tubular Operations, $13 million and $32 million for employee benefit costs related to Company-wide headcount reductions and headcount reductions under a VERP offered at USSK, respectively. Cash payments were made related to severance and exit costs of approximately $130 million. A portion of these cash payments, approximately $29 million, were funded by the postretirement benefit trust (VEBA) per an agreement with the United Steelworkers of America. The activity in the accrued balances incurred in relation to restructuring programs during the nine months ended September 30, 2020 were as follows: (In millions) Employee Related Costs Exit Costs Non-cash Charges Total Balance at December 31, 2019 $ 87 $ 125 $ — $ 212 Additional charges 75 51 4 130 Cash payments/utilization (93) (37) (4) (134) Balance at September 30, 2020 $ 69 $ 139 $ — $ 208 Accrued liabilities for restructuring programs are included in the following balance sheet lines: (In millions) September 30, 2020 December 31, 2019 Accounts payable $ 47 $ 46 Payroll and benefits payable 38 64 Employee benefits 30 23 Deferred credits and other noncurrent liabilities 93 79 Total $ 208 $ 212

Contingencies and Commitments

Contingencies and Commitments	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Contingencies and Commitments	21. Contingencies and Commitments U. S. Steel is the subject of, or party to, a number of pending or threatened legal actions, contingencies and commitments involving a variety of matters, including laws and regulations relating to the environment. Certain of these matters are discussed below. The ultimate resolution of these contingencies could, individually or in the aggregate, be material to the Condensed Consolidated Financial Statements. However, management believes that U. S. Steel will remain a viable and competitive enterprise even though it is possible that these contingencies could be resolved unfavorably. U. S. Steel accrues for estimated costs related to existing lawsuits, claims and proceedings when it is probable that it will incur these costs in the future and the costs are reasonably estimable. Asbestos matters – As of September 30, 2020, U. S. Steel was a defendant in approximately 850 active cases involving approximately 2,435 plaintiffs. The vast majority of these cases involve multiple defendants. About 1,540, or approximately 63 percent, of these plaintiff claims are currently pending in jurisdictions which permit filings with massive numbers of plaintiffs. At December 31, 2019, U. S. Steel was a defendant in approximately 800 cases involving approximately 2,390 plaintiffs. Based upon U. S. Steel’s experience in such cases, it believes that the actual number of plaintiffs who ultimately assert claims against U. S. Steel will likely be a small fraction of the total number of plaintiffs. The following table shows the number of asbestos claims in the current period and the prior three years: Period ended Opening Claims Dismissed, Settled and Resolved (a) New Claims Closing December 31, 2017 3,340 275 250 3,315 December 31, 2018 3,315 1,285 290 2,320 December 31, 2019 2,320 195 265 2,390 September 30, 2020 2,390 185 230 2,435 (a) The period ending December 31, 2018 includes approximately 1,000 dismissed cases previously pending in the State of Texas. The amount U. S. Steel accrues for pending asbestos claims is not material to U. S. Steel’s financial condition. However, U. S. Steel is unable to estimate the ultimate outcome of asbestos-related claims due to a number of uncertainties, including: (1) the rates at which new claims are filed, (2) the number of and effect of bankruptcies of other companies traditionally defending asbestos claims, (3) uncertainties associated with the variations in the litigation process from jurisdiction to jurisdiction, (4) uncertainties regarding the facts, circumstances and disease process with each claim, and (5) any new legislation enacted to address asbestos-related claims. Further, U. S. Steel does not believe that an accrual for unasserted claims is required. At any given reporting date, it is probable that there are unasserted claims that will be filed against the Company in the future. In 2019, the Company engaged an outside valuation consultant to assist in assessing its ability to estimate an accrual for unasserted claims. This assessment was based on the Company's settlement experience, including recent claims trends. The analysis focused on settlements made over the last several years as these claims are likely to best represent future claim characteristics. After review by the valuation consultant and U. S. Steel management, it was determined that the Company could not estimate an accrual for unasserted claims. Despite these uncertainties, management believes that the ultimate resolution of these matters will not have a material adverse effect on U. S. Steel’s financial condition. Environmental matters – U. S. Steel is subject to federal, state, local and foreign laws and regulations relating to the environment. These laws generally provide for control of pollutants released into the environment and require responsible parties to undertake remediation of hazardous waste disposal sites. Penalties may be imposed for noncompliance. Changes in accrued liabilities for remediation activities where U. S. Steel is identified as a named party are summarized in the following table: (In millions) Nine Months Ended September 30, 2020 Beginning of period $ 186 Accruals for environmental remediation deemed probable and reasonably estimable 5 Obligations settled (29) End of period $ 162 Accrued liabilities for remediation activities are included in the following Condensed Consolidated Balance Sheet lines: (In millions) September 30, 2020 December 31, 2019 Accounts payable $ 52 $ 53 Deferred credits and other noncurrent liabilities 110 133 Total $ 162 $ 186 Expenses related to remediation are recorded in cost of sales and were immaterial for both the three and nine-month periods ended September 30, 2020 and September 30, 2019. It is not currently possible to estimate the ultimate amount of all remediation costs that might be incurred or the penalties that may be imposed. Due to uncertainties inherent in remediation projects and the associated liabilities, it is reasonably possible that total remediation costs for active matters may exceed the accrued liabilities by as much as 20 to 30 percent. Remediation Projects U. S. Steel is involved in environmental remediation projects at or adjacent to several current and former U. S. Steel facilities and other locations that are in various stages of completion ranging from initial characterization through post-closure monitoring. Based on the anticipated scope and degree of uncertainty of projects, the Company categorizes projects as follows: (1) Projects with Ongoing Study and Scope Development - Projects which are still in the development phase. For these projects, the extent of remediation that may be required is not yet known, the remediation methods and plans are not yet developed, and/or cost estimates cannot be determined. Therefore, significant costs, in addition to the accrued liabilities for these projects, are reasonably possible. There are five environmental remediation projects where additional costs for completion are not currently estimable, but could be material. These projects are at Fairfield Works, Lorain Tubular, USS-POSCO Industries (UPI), the Fairless Plant, and the former steelmaking plant at Joliet, Illinois. As of September 30, 2020, accrued liabilities for these projects totaled $1 million for the costs of studies, investigations, interim measures, design and/or remediation. It is reasonably possible that additional liabilities associated with future requirements regarding studies, investigations, design and remediation for these projects could be as much as $25 million to $40 million. (2) Significant Projects with Defined Scope - Projects with significant accrued liabilities with a defined scope. As of September 30, 2020, there are four significant projects with defined scope greater than or equal to $5 million each, with a total accrued liability of $105 million. These projects are Gary Resource Conservation and Recovery Act (RCRA) (accrued liability of $27 million), the former Geneva facility (accrued liability of $26 million), the Cherryvale zinc site (accrued liability of $8 million) and the former Duluth facility St. Louis River Estuary (accrued liability of $44 million). (3) Other Projects with a Defined Scope - Projects with relatively small accrued liabilities for which we believe that, while additional costs are possible, they are not likely to be significant, and also include those projects for which we do not yet possess sufficient information to estimate potential costs to U. S. Steel. There are two other environmental remediation projects which each had an accrued liability of between $1 million and $5 million. The total accrued liability for these projects at September 30, 2020 was $3 million. These projects have progressed through a significant portion of the design phase and material additional costs are not expected. The remaining environmental remediation projects each have an accrued liability of less than $1 million each. The total accrued liability for these projects at September 30, 2020 was approximately $3 million. The Company does not foresee material additional liabilities for any of these sites. Post-Closure Costs – Accrued liabilities for post-closure site monitoring and other costs at various closed landfills totaled $23 million at September 30, 2020 and were based on known scopes of work. Administrative and Legal Costs – As of September 30, 2020, U. S. Steel had an accrued liability of $11 million for administrative and legal costs related to environmental remediation projects. These accrued liabilities were based on projected administrative and legal costs for the next three years and do not change significantly from year to year. Capital Expenditures – For a number of years, U. S. Steel has made substantial capital expenditures to comply with various regulations, laws and other requirements relating to the environment. In the first nine months of 2020 and 2019, such capital expenditures totaled $8 million and $40 million, respectively. U. S. Steel anticipates making additional such expenditures in the future, which may be material; however, the exact amounts and timing of such expenditures are uncertain because of the continuing evolution of specific regulatory requirements. EU Environmental Requirements - Under the Emissions Trading Scheme (ETS), USSK's final allocation of allowances for the Phase III period, which covers the years 2013 through 2020 is 48 million allowances. Based on projected total production levels, we started to purchase allowances in the third quarter of 2017 to meet the annual compliance submission in the future. As of September 30, 2020, we have purchased approximately 12.3 million European Union Allowances totaling €141.1 million (approximately $165.2 million) to cover the estimated shortfall of emission allowances. We estimate that the total shortfall will be approximately 12.2 million allowances for the Phase III period. The exact cost of complying with the ETS regulations will depend on future production levels and future emissions intensity levels, however our estimated shortfall of emission allowances is covered by purchased European Union Allowances. The EU’s Industrial Emissions Directive requires implementation of EU determined best available techniques (BAT) for Iron and Steel production to reduce environmental impacts as well as compliance with BAT associated emission levels. Our most recent estimate of total capital expenditures for projects to comply with or go beyond BAT requirements is €138 million (approximately $161.6 million) over the actual program period. These costs may be mitigated if USSK complies with certain financial covenants, which are assessed annually according to EU funding rules. USSK complied with these covenants as of September 30, 2020. If we are unable to meet these covenants in the future, USSK might be required to provide additional collateral (e.g. bank guarantee) to secure the full value of estimated expenditures. Environmental indemnifications – Throughout its history, U. S. Steel has sold numerous properties and businesses and many of these sales included indemnifications and cost sharing agreements related to the assets that were divested. The amount of potential environmental liability associated with these transactions and properties is not estimable due to the nature and extent of the unknown conditions related to the properties divested and deconsolidated. Aside from the environmental liabilities already recorded as a result of these transactions due to specific environmental remediation activities and cases (included in the $162 million of accrued liabilities for remediation discussed above), there are no other known probable and estimable environmental liabilities related to these transactions. Guarantees – The maximum guarantees of the indebtedness of unconsolidated entities of U. S. Steel totaled $7 million at September 30, 2020. Other contingencies – Under certain operating lease agreements covering various equipment, U. S. Steel has the option to renew the lease or to purchase the equipment at the end of the lease term. If U. S. Steel does not exercise the purchase option by the end of the lease term, U. S. Steel guarantees a residual value of the equipment as determined at the lease inception date (totaling approximately $23 million at September 30, 2020). No liability has been recorded for these guarantees as the potential loss is not probable. Insurance – U . S. Steel maintains insurance for certain property damage, equipment, business interruption and general liability exposures; however, insurance is applicable only after certain deductibles and retainages. U. S. Steel is self-insured for certain other exposures including workers’ compensation (where permitted by law) and auto liability. Liabilities are recorded for workers’ compensation and personal injury obligations. Other costs resulting from losses under deductible or retainage amounts or not otherwise covered by insurance are charged against income upon occurrence. U. S. Steel uses surety bonds, trusts and letters of credit to provide whole or partial financial assurance for certain obligations such as workers’ compensation. The total amount of active surety bonds, trusts and letters of credit being used for financial assurance purposes was approximately $210 million as of September 30, 2020, which reflects U. S. Steel’s maximum exposure under these financial guarantees, but not its total exposure for the underlying obligations. A significant portion of our trust arrangements and letters of credit are collateralized by the Credit Facility Agreement. The remaining trust arrangements and letters of credit are collateralized by restricted cash. Restricted cash, which is recorded in other current and noncurrent assets, totaled $91 million and $190 million at September 30, 2020 and December 31, 2019, respectively. Capital Commitments – At September 30, 2020, U. S. Steel’s contractual commitments to acquire property, plant and equipment totaled $730 million. Contractual Purchase Commitments – U. S. Steel is obligated to make payments under contractual purchase commitments, including unconditional purchase obligations. Payments for contracts with remaining terms in excess of one year are summarized below (in millions): Remainder of 2020 2021 2022 2023 2024 Later Total $162 $694 $621 $386 $163 $832 $2,858 The majority of U. S. Steel’s unconditional purchase obligations relates to the supply of industrial gases, and certain energy and utility services with terms ranging from two Total payments relating to unconditional purchase obligations were $123 million and $167 million for the three months ended September 30, 2020 and 2019, respectively, and $425 million and $493 million for the nine months ended September 30, 2020 and 2019, respectively.

Significant Equity Investments

Significant Equity Investments	9 Months Ended
	Sep. 30, 2020
Equity Method Investments and Joint Ventures [Abstract]
Significant Equity Investments	22. Significant Equity Investments Summarized unaudited income statement information for our significant equity investments for the nine months ended September 30, 2020 and 2019 is reported below (amounts represent 100% of investee financial information): (In millions) 2020 2019 Net sales $ 1,087 $ 1,857 Cost of sales 983 1,624 Operating income 36 190 Net earnings 5 172 Net earnings attributable to significant equity investments 5 172 U. S. Steel's portion of the equity in net (loss) earnings of the significant equity investments above was $(11) million and $66 million for the nine months ended September 30, 2020 and 2019, respectively, which is included in the (loss) earnings from investees line on the Condensed Consolidated Statement of Operations. While no equity investments

Common Stock Repurchase Program

Common Stock Repurchase Program	9 Months Ended
	Sep. 30, 2020
Common Stock Repurchase Program [Abstract]
Common Stock Repurchase Program	23. Common Stock Issued and Repurchased On June 22, 2020, U. S. Steel issued 50 million shares of common stock (par value $1 per share) at a price of $8.2075 per share, resulting in net proceeds of approximately $410 million. During the nine months ended September 30, 2019, U. S. Steel repurchased 5,289,475 shares of common stock for approximately $88 million. In December 2019, the Board of Directors terminated the authorization for the common stock repurchase program that was announced in November 2018.

Recently Adopted Accounting S_2

Recently Adopted Accounting Standards (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recently Adopted Accounting Standards	3. Recently Adopted Accounting Standard In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13), which adds an impairment model that is based on expected losses rather than incurred losses. Under ASU 2016-13, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. ASU 2016-13 was effective for public companies for fiscal years beginning after December 15, 2019 including interim reporting periods. U. S. Steel adopted this standard effective January 1, 2020. The impact of adoption was not material to the Condensed Consolidated Financial Statements. U. S. Steel's significant financial instruments which are valued at cost are trade receivables (receivables). U. S. Steel's receivables carry standard industry terms and are categorized in two receivable pools, U.S. and U. S. Steel Europe (USSE). Both pools use customer specific risk ratings based on customer financial metrics, past payment experience and other factors and qualitatively consider economic conditions to assess the level of allowance for doubtful accounts. USSE mitigates credit risk for approximately 75 percent of its receivables balance using credit insurance, letters of credit, bank guarantees, prepayments or other collateral. Below is a summary of the allowance for doubtful accounts for the segments. Additional reserve recorded in the nine month period ended September 30, 2020 primarily reflects uncertainty over near-term anticipated market conditions. (in millions) U.S. USSE Total Allowance Balance at December 31, 2019 $ 12 $ 16 $ 28 Additional reserve 5 1 6 Balance at September 30, 2020 $ 17 $ 17 $ 34

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Results of Segment Operations	The results of segment operations for the three months ended September 30, 2020 and 2019 are: (In millions) Three Months Ended September 30, 2020 Customer Intersegment Net (Loss) Earnings Earnings (loss) before interest and income taxes Flat-Rolled $ 1,728 $ 71 $ 1,799 $ (3) $ (159) USSE 495 1 496 — 13 Tubular 96 — 96 — (52) Total reportable segments 2,319 72 2,391 (3) (198) Other Businesses 21 23 44 (28) (13) Reconciling Items and Eliminations — (95) (95) — — Total $ 2,340 $ — $ 2,340 $ (31) $ (211) Three Months Ended September 30, 2019 Flat-Rolled $ 2,277 $ 86 $ 2,363 $ 30 $ 46 USSE 518 3 521 — (46) Tubular 262 1 263 1 (25) Total reportable segments 3,057 90 3,147 31 (25) Other Businesses 12 28 40 — 8 Reconciling Items and Eliminations — (118) (118) — (63) Total $ 3,069 $ — $ 3,069 $ 31 $ (80) The results of segment operations for the nine months ended September 30, 2020 and 2019 are: (In millions) Nine Months Ended September 30, 2020 Customer Intersegment Net (Loss) Earnings Earnings (loss) before interest and income taxes Flat-Rolled $ 5,199 $ 175 $ 5,374 $ (15) $ (523) USSE 1,403 3 1,406 — (27) Tubular 533 6 539 3 (147) Total reportable segments 7,135 184 7,319 (12) (697) Other Businesses 44 70 114 (66) (33) Reconciling Items and Eliminations — (254) (254) — (388) Total $ 7,179 $ — $ 7,179 $ (78) $ (1,118) Nine Months Ended September 30, 2019 Flat-Rolled $ 7,221 $ 250 $ 7,471 $ 63 $ 275 USSE 1,933 9 1,942 — (27) Tubular 921 4 925 5 (21) Total reportable segments 10,075 263 10,338 68 227 Other Businesses 38 88 126 — 26 Reconciling Items and Eliminations — (351) (351) — (107) Total $ 10,113 $ — $ 10,113 $ 68 $ 146
Schedule of reconciling items to EBIT	The following is a schedule of reconciling items to consolidated earnings before interest and income taxes: Three Months Ended September 30, Nine Months Ended September 30, (In millions) 2020 2019 2020 2019 Items not allocated to segments: Asset impairment charges (Notes 1 and 9) $ — $ — $ (263) $ — Restructuring and other charges (Note 20) — (54) (130) (54) Gain on previously held investment in UPI — — 25 — Tubular inventory impairment charge — — (24) — December 24, 2018 Clairton coke making facility fire — (9) 4 (53) Total reconciling items $ — $ (63) $ (388) $ (107)

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue by Product	Net Sales by Product (In millions): Three Months Ended September 30, 2020 Flat-Rolled USSE Tubular Other Businesses Total Semi-finished $ 5 $ — $ — $ — $ 5 Hot-rolled sheets 239 193 — — 432 Cold-rolled sheets 555 43 — — 598 Coated sheets 778 233 — — 1,011 Tubular products — 11 91 — 102 All Other (a) 151 15 5 21 192 Total $ 1,728 $ 495 $ 96 $ 21 $ 2,340 (a) Consists primarily of sales of raw materials and coke making by-products. Three Months Ended September 30, 2019 Flat-Rolled USSE Tubular Other Businesses Total Semi-finished $ 69 $ 2 $ — $ — $ 71 Hot-rolled sheets 537 199 — — 736 Cold-rolled sheets 627 59 — — 686 Coated sheets 765 231 — — 996 Tubular products — 11 257 — 268 All Other (a) 279 16 5 12 312 Total $ 2,277 $ 518 $ 262 $ 12 $ 3,069 (a) Consists primarily of sales of raw materials and coke making by-products. Nine Months Ended September 30, 2020 Flat-Rolled USSE Tubular Other Businesses Total Semi-finished $ 63 $ 2 $ — $ — $ 65 Hot-rolled sheets 980 544 — — 1,524 Cold-rolled sheets 1,495 114 — — 1,609 Coated sheets 2,202 664 — — 2,866 Tubular products — 31 520 — 551 All Other (a) 459 48 13 44 564 Total $ 5,199 $ 1,403 $ 533 $ 44 $ 7,179 (a) Consists primarily of sales of raw materials and coke making by-products. Nine Months Ended September 30, 2019 Flat-Rolled USSE Tubular Other Businesses Total Semi-finished $ 278 $ 11 $ — $ — $ 289 Hot-rolled sheets 1,982 818 — — 2,800 Cold-rolled sheets 1,931 229 — — 2,160 Coated sheets 2,309 779 — — 3,088 Tubular products — 31 903 — 934 All Other (a) 721 65 18 38 842 Total $ 7,221 $ 1,933 $ 921 $ 38 $ 10,113

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash (Tables)	9 Months Ended
	Sep. 30, 2020
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within U. S. Steel's Condensed Consolidated Balance Sheets that sum to the total of the same amounts shown in the Condensed Consolidated Statement of Cash Flows: (In millions) September 30, 2020 September 30, 2019 Cash and cash equivalents $ 1,696 $ 476 Restricted cash in other current assets 2 — Restricted cash in other noncurrent assets 89 20 Total cash, cash equivalents and restricted cash $ 1,787 $ 496
Schedule of Restricted Cash and Restricted Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within U. S. Steel's Condensed Consolidated Balance Sheets that sum to the total of the same amounts shown in the Condensed Consolidated Statement of Cash Flows: (In millions) September 30, 2020 September 30, 2019 Cash and cash equivalents $ 1,696 $ 476 Restricted cash in other current assets 2 — Restricted cash in other noncurrent assets 89 20 Total cash, cash equivalents and restricted cash $ 1,787 $ 496

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Inventories	(In millions) September 30, 2020 December 31, 2019 Raw materials $ 465 $ 628 Semi-finished products 557 720 Finished products 320 376 Supplies and sundry items 56 61 Total $ 1,398 $ 1,785

Intangible Assets (Tables)

Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Amortizable Intangible Assets	Intangible assets that are being amortized on a straight-line basis over their estimated useful lives are detailed below: As of September 30, 2020 As of December 31, 2019 (In millions) Useful Gross Accumulated Impairment (a) Accumulated Net Gross Accumulated Net Customer relationships 22 Years $ 132 $ 55 $ 77 $ — $ 132 $ 76 $ 56 Patents 10-15 Years 22 7 10 5 22 8 14 Energy Contract 10 Years 54 — 3 51 — — — Other 4-20 Years 14 5 9 — 14 9 5 Total amortizable intangible assets $ 222 $ 67 $ 99 $ 56 $ 168 $ 93 $ 75

Pensions and Other Benefits (Ta

Pensions and Other Benefits (Tables)	9 Months Ended
	Sep. 30, 2020
Retirement Benefits [Abstract]
Net Periodic Benefit Cost	The following table reflects the components of net periodic benefit cost for the three months ended September 30, 2020 and 2019: Pension Other (In millions) 2020 2019 2020 2019 Service cost $ 13 $ 11 $ 3 $ 4 Interest cost 49 59 16 22 Expected return on plan assets (84) (81) (20) (19) Amortization of prior service cost — — (1) 8 Amortization of actuarial net loss (gain) 36 33 (4) — Net periodic benefit cost, excluding below 14 22 (6) 15 Multiemployer plans 19 20 — — Settlement, termination and curtailment losses (a) 2 3 — — Net periodic benefit cost $ 35 $ 45 $ (6) $ 15 (a) During the three months ended September 30, 2020 and 2019, the pension plan incurred settlement charges of approximately $2 million and $3 million, respectively, due to lump sum payments for certain individuals. The following table reflects the components of net periodic benefit cost for the nine months ended September 30, 2020 and 2019: Pension Other (In millions) 2020 2019 2020 2019 Service cost $ 38 $ 33 $ 9 $ 10 Interest cost 145 178 48 68 Expected return on plan assets (249) (243) (60) (59) Amortization of prior service cost 1 1 (5) 22 Amortization of actuarial net loss (gain) 108 99 (12) 2 Net periodic benefit cost, excluding below 43 68 (20) 43 Multiemployer plans 58 57 — — Settlement, termination and curtailment losses (a) 10 3 — — Net periodic benefit cost $ 111 $ 128 $ (20) $ 43 (a) During the nine months ended September 30, 2020 and 2019, the pension plan incurred settlement and special termination charges of approximately $10 million and $3 million, respectively, due to workforce restructuring and lump sum payments made to certain individuals.

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Summary of Awards Made under Plans	The following table is a summary of the awards made under the Omnibus Plan during the first nine months of 2020 and 2019. 2020 2019 Grant Details Shares (a) Fair Value (b) Shares (a) Fair Value (b) Restricted Stock Units 2,640,690 $ 8.82 1,005,500 $ 23.76 Performance Awards (c) TSR 671,390 $ 8.19 210,520 $ 29.22 ROCE (d) — $ — 527,470 $ 23.90 (a) The share amounts shown in this table do not reflect an adjustment for estimated forfeitures. (b) Represents the per share weighted-average for all grants during the period. (c) The number of performance awards shown represents the target share grant of the award. (d) The ROCE awards granted in 2020 are not shown in the table because they were granted in cash.

Earnings and Dividends Per Co_2

Earnings and Dividends Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Computations for Basic and Diluted Earnings Per Common Share from Continuing Operations	Three Months Ended September 30, Nine Months Ended September 30, (Dollars in millions, except per share amounts) 2020 2019 2020 2019 (Loss) earnings attributable to United States Steel Corporation stockholders $ (234) $ (84) $ (1,214) $ 38 Weighted-average shares outstanding (in thousands): Basic 220,402 170,801 188,766 171,882 Effect of Senior Convertible Notes — — — — Effect of stock options, restricted stock units and performance awards — — — 629 Adjusted weighted-average shares outstanding, diluted 220,402 170,801 188,766 172,511 Basic (loss) earnings per common share $ (1.06) $ (0.49) $ (6.43) $ 0.22 Diluted (loss) earnings per common share $ (1.06) $ (0.49) $ (6.43) $ 0.22

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions	The table below shows the outstanding swap quantities used to hedge forecasted purchases and sales as of September 30, 2020 and September 30, 2019: Hedge Contracts Classification September 30, 2020 September 30, 2019 Natural gas (in mmbtus) Commodity purchase swaps 34,222,000 56,873,000 Tin (in metric tons) Commodity purchase swaps 787 530 Zinc (in metric tons) Commodity purchase swaps 8,148 14,561 Electricity (in megawatt hours) Commodity purchase swaps 847,680 — Foreign currency (in millions of euros) Foreign exchange forwards € 240 € 316 Foreign currency (in millions of CAD) Foreign exchange forwards $ 8 $ 33
Schedule of Effect of Hedge Accounting on Accumulated Other Comprehensive Income	The table below summarizes the effect of hedge accounting on AOCI and amounts reclassified from AOCI into earnings for the three and nine months ended September 30, 2020 and 2019: Gain (Loss) on Derivatives in AOCI Amount of Gain (Loss) Recognized in Income (In millions) Three Months Ended September 30, 2020 Three Months Ended September 30, 2019 Location of Reclassification from AOCI (a) Three Months Ended September 30, 2020 Three Months Ended September 30, 2019 Commodity purchase swaps 19 (6) Cost of sales (c) (6) (4) Foreign exchange forwards (b) (9) 3 Cost of sales (3) — (a) The earnings impact of hedging instruments substantially offsets the earnings impact of the related hedged items since ineffectiveness is less than $1 million. (b) U. S. Steel has elected hedge accounting prospectively for European foreign exchange forwards on July 1, 2019. (c) Costs for commodity purchase swaps are recognized in cost of sales as products are sold. Gain (Loss) on Derivatives in AOCI Amount of Gain (Loss) Recognized in Income (In millions) Nine Months Ended September 30, 2020 Nine Months Ended September 30, 2019 Location of Reclassification from AOCI (a) Nine Months Ended September 30, 2020 Nine Months Ended September 30, 2019 Commodity purchase swaps 30 (2) Cost of sales (c) (26) (14) Foreign exchange forwards (b) (8) 4 Cost of sales (2) — (a) The earnings impact of hedging instruments substantially offsets the earnings impact of the related hedged items since ineffectiveness is less than $1 million. (b) U. S. Steel has elected hedge accounting prospectively for European foreign exchange forwards on July 1, 2019. (c) Costs for commodity purchase swaps are recognized in cost of sales as products are sold.

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt	(In millions) Interest Maturity September 30, 2020 December 31, 2019 2037 Senior Notes 6.650 2037 $ 350 $ 350 2026 Senior Notes 6.250 2026 650 650 2026 Senior Convertible Notes 5.000 2026 350 350 2025 Senior Notes 6.875 2025 750 750 2025 Senior Secured Notes 12.000 2025 1,056 — Export-Import Credit Agreement Variable 2021 250 — Environmental Revenue Bonds 4.875 - 6.750 2024 - 2049 620 620 Fairfield Caster Lease 2022 17 18 Other finance leases and all other obligations 2020 - 2029 69 48 ECA Credit Agreement Variable 2031 104 — Credit Facility Agreement, $2.0 billion Variable 2024 500 600 UPI Amended Credit Facility Variable 2020 — — USSK Credit Agreement Variable 2023 410 393 USSK Credit Facilities Variable 2021 — — Total Debt 5,126 3,779 Less unamortized discount and debt issuance costs 236 138 Less short-term debt and long-term debt due within one year 262 14 Long-term debt $ 4,628 $ 3,627
Summary of Debt Instrument Redemption Percentages	The Company may redeem the 2025 Senior Secured Notes, in whole or part, at its option on or after June 1, 2022 at the redemption price for such notes as a percentage of the principal amount, plus accrued and unpaid interest to, but excluding, the redemption date, if redeemed during the twelve-month period beginning on June 1st of each of the years indicated below. Year Redemption Price 2022 106 % 2023 103 % 2024 and thereafter 100 %

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Schedule of the Change in Fair Value by Option	The following table shows the change in fair value by option for the nine month period ended September 30, 2020. (In millions) Balance Sheet Location Fair Value asset/(liability) Fair Value Fair Value asset/(liability) U. S. Steel Call Option Investments and Long-Term Receivables $ 166 $ (96) $ 70 Class B Common Deferred credits and other noncurrent liabilities $ (192) $ 135 $ (57) Class B Common Deferred credits and other noncurrent liabilities $ (2) $ 1 $ (1) Net Mark to Market Impact $ 40
Financial Assets and Liabilities Not Carried at Fair Value	The following table summarizes U. S. Steel’s financial liabilities that were not carried at fair value at September 30, 2020 and December 31, 2019. The fair value of long-term debt was determined using Level 2 inputs. September 30, 2020 December 31, 2019 (In millions) Fair Carrying Fair Carrying Financial liabilities: Short-term and long-term debt (a) $ 4,448 $ 4,804 $ 3,576 $ 3,575 (a) Excludes finance lease obligations.

Statement of Changes in Stock_2

Statement of Changes in Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Consolidated Statement of Changes in Equity	The following table reflects the first nine months of 2020 and 2019 reconciliation of the carrying amount of total equity, equity attributable to U. S. Steel and equity attributable to noncontrolling interests: Nine Months Ended September 30, 2020 (In millions) Total Retained Earnings (Accumulated Deficit) Accumulated Common Treasury Paid-in Non- Balance at beginning of year $ 4,093 $ 544 $ (478) $ 179 $ (173) $ 4,020 $ 1 Comprehensive income (loss): Net loss (391) (391) — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 52 — 52 — — — — Currency translation adjustment (23) — (23) — — — — Derivative financial instruments (5) — (5) Employee stock plans 2 — — — (2) 4 — Dividends paid on common stock (2) (2) — — — — — Balance at March 31, 2020 $ 3,726 $ 151 $ (454) $ 179 $ (175) $ 4,024 $ 1 Comprehensive income (loss): Net loss (589) (589) — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 29 — 29 — — — — Currency translation adjustment 20 — 20 — — — — Derivative financial instruments 15 — 15 — — — — Employee stock plans 8 — — — — 8 — Common Stock Issued 410 — — 50 — 360 — Dividends paid on common stock (1) — — — — (1) — Stelco Option Agreement 37 — — — — — 37 Other (1) — — — — — (1) Balance at June 30, 2020 $ 3,654 $ (438) $ (390) $ 229 $ (175) $ 4,391 $ 37 Comprehensive income (loss): Net loss (234) (234) — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 16 — 16 — — — — Currency translation adjustment 34 — 34 — — — — Derivative financial instruments 8 — 8 — — — — Employee stock plans 10 — — — — 10 — Dividends paid on common stock (3) — — — — (3) — Stelco Option Agreement 18 — — — — 18 Other 1 1 — — — — — Balance at September 30, 2020 $ 3,504 $ (671) $ (332) $ 229 $ (175) $ 4,398 $ 55 Nine Months Ended September 30, 2019 (In millions) Total Retained Earnings Accumulated Common Treasury Paid-in Non- Balance at beginning of year $ 4,203 $ 1,212 $ (1,026) $ 177 $ (78) $ 3,917 $ 1 Comprehensive income (loss): Net earnings 54 54 — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 32 — 32 — — — — Currency translation adjustment (17) — (17) — — — — Derivative financial instruments 15 15 Employee stock plans 2 — — 1 (6) 7 — Common stock repurchased (42) — — — (42) — — Dividends paid on common stock (9) (9) — — — — — Cumulative effect upon adoption of lease accounting standard (2) (2) — — — — — Balance at March 31, 2019 $ 4,236 $ 1,255 $ (996) $ 178 $ (126) $ 3,924 $ 1 Comprehensive income (loss): Net earnings 68 68 — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 32 — 32 — — — — Currency translation adjustment 12 — 12 — — — — Derivative financial instruments (11) — (11) — — — — Employee stock plans 12 — — 1 (1) 12 — Common stock repurchased (28) — — — (28) — — Dividends paid on common stock (9) (9) — — — — — Balance at June 30, 2019 $ 4,312 $ 1,314 $ (963) $ 179 $ (155) $ 3,936 $ 1 Comprehensive income (loss): Net loss (84) (84) — — — — — Other comprehensive income (loss), net of tax: Pension and other benefit adjustments 30 — 30 — — — — Currency translation adjustment (40) — (40) — — — — Derivative financial instruments (2) — (2) — — — — Employee stock plans 11 — — — — 11 — Common stock repurchased (18) — — — (18) — — Dividends paid on common stock (8) (8) — — — — — Other (1) (1) — — — — — Balance at September 30, 2019 $ 4,200 $ 1,221 $ (975) $ 179 $ (173) $ 3,947 $ 1

Reclassifications from Accumu_2

Reclassifications from Accumulated Other Comprehensive Income (AOCI) (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Other Comprehensive Income Activity Net of Tax	(In millions) Pension and Foreign Unrealized Gain (Loss) on Derivatives Total Balance at December 31, 2019 $ (843) $ 381 $ (16) $ (478) Other comprehensive income (loss) before reclassifications 6 31 (6) 31 Amounts reclassified from AOCI (a) 91 — 24 115 Net current-period other comprehensive income (loss) 97 31 18 146 Balance at September 30, 2020 $ (746) $ 412 $ 2 $ (332) Balance at December 31, 2018 $ (1,416) $ 403 $ (13) $ (1,026) Other comprehensive (loss) income before reclassifications (3) (45) (12) (60) Amounts reclassified from AOCI (a) 97 — 14 111 Net current-period other comprehensive income (loss) 94 (45) 2 51 Balance at September 30, 2019 $ (1,322) $ 358 $ (11) $ (975) (a) See table below for further details.
Defined Benefit Plan In other Comprehensive Income	Amount reclassified from AOCI (a) Three Months Ended September 30, Nine Months Ended September 30, Details about AOCI components (in millions) 2020 2019 2020 2019 Amortization of pension and other benefit items Prior service costs (a) $ (1) $ 8 $ (4) $ 23 Actuarial losses (a) 32 33 96 101 Settlement, termination and curtailment losses (a) 2 3 2 3 UPI Purchase Accounting Adjustment — — 23 — Total pensions and other benefits items 33 44 117 127 Derivative reclassifications to Condensed Consolidated Statements of Operations 6 5 28 19 Total before tax 39 49 145 146 Tax provision (15) (12) (30) (35) Net of tax $ 24 $ 37 $ 115 $ 111 (a) These AOCI components are included in the computation of net periodic benefit cost (see Note 10 for additional details).

Restructuring and Other Charg_2

Restructuring and Other Charges (Tables)	9 Months Ended
	Sep. 30, 2020
Restructuring and Related Activities [Abstract]
Schedule of Accrued Balances From Restructuring and Other Charges	The activity in the accrued balances incurred in relation to restructuring programs during the nine months ended September 30, 2020 were as follows: (In millions) Employee Related Costs Exit Costs Non-cash Charges Total Balance at December 31, 2019 $ 87 $ 125 $ — $ 212 Additional charges 75 51 4 130 Cash payments/utilization (93) (37) (4) (134) Balance at September 30, 2020 $ 69 $ 139 $ — $ 208
Schedule of Accrued Liabilities for Restructuring on Balance Sheet	Accrued liabilities for restructuring programs are included in the following balance sheet lines: (In millions) September 30, 2020 December 31, 2019 Accounts payable $ 47 $ 46 Payroll and benefits payable 38 64 Employee benefits 30 23 Deferred credits and other noncurrent liabilities 93 79 Total $ 208 $ 212

Contingencies and Commitments (

Contingencies and Commitments (Tables)	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Asbestos Litigation Activity	The following table shows the number of asbestos claims in the current period and the prior three years: Period ended Opening Claims Dismissed, Settled and Resolved (a) New Claims Closing December 31, 2017 3,340 275 250 3,315 December 31, 2018 3,315 1,285 290 2,320 December 31, 2019 2,320 195 265 2,390 September 30, 2020 2,390 185 230 2,435
Changes in Accrued Liabilities for Remediation Activities	Changes in accrued liabilities for remediation activities where U. S. Steel is identified as a named party are summarized in the following table: (In millions) Nine Months Ended September 30, 2020 Beginning of period $ 186 Accruals for environmental remediation deemed probable and reasonably estimable 5 Obligations settled (29) End of period $ 162
Accrued Liabilities for Remediation Activities Included in Balance Sheet	Accrued liabilities for remediation activities are included in the following Condensed Consolidated Balance Sheet lines: (In millions) September 30, 2020 December 31, 2019 Accounts payable $ 52 $ 53 Deferred credits and other noncurrent liabilities 110 133 Total $ 162 $ 186
Payments for Contracts with Remaining Terms in Excess of One Year	Payments for contracts with remaining terms in excess of one year are summarized below (in millions): Remainder of 2020 2021 2022 2023 2024 Later Total $162 $694 $621 $386 $163 $832 $2,858

Significant Equity Investments

Significant Equity Investments (Tables)	9 Months Ended
	Sep. 30, 2020
Equity Method Investments and Joint Ventures [Abstract]
Summarized Unaudited Income Statement Information for Significant Equity Investments	Summarized unaudited income statement information for our significant equity investments for the nine months ended September 30, 2020 and 2019 is reported below (amounts represent 100% of investee financial information): (In millions) 2020 2019 Net sales $ 1,087 $ 1,857 Cost of sales 983 1,624 Operating income 36 190 Net earnings 5 172 Net earnings attributable to significant equity investments 5 172

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Summary Of Significant Accounting Policies [Line Items]
Asset impairment charges (Note 1)	$ 0		$ 0	$ 263	$ 0
Welded Tubular Asset Group
Summary Of Significant Accounting Policies [Line Items]
Asset impairment charges (Note 1)		$ 263
Tangible Asset Impairment Charges		196
Impairment of Intangible Assets (Excluding Goodwill)		$ 67

Recently Adopted Accounting S_3

Recently Adopted Accounting Standards - Narrative (Details)	Sep. 30, 2020pool
Accounting Changes and Error Corrections [Abstract]
Number of receivable pools	2
Percent of receivables balance covered by credit insurance	75.00%

Recently Adopted Accounting S_4

Recently Adopted Accounting Standards - Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	$ 28
Additional reserve	6
Balance at September 30, 2020	28	$ 34
U.S.
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	12
Additional reserve	5
Balance at September 30, 2020	12	17
USSE
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	16
Additional reserve	1
Balance at September 30, 2020	$ 16	$ 17

Segment Information - Additiona

Segment Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2020Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segment Information - Results o

Segment Information - Results of Segment Operations (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 2,340	$ 3,069	$ 7,179	$ 10,113
(Loss) Earnings from investees	(31)	31	(78)	68
Earnings (loss) before interest and income taxes	(211)	(80)	(1,118)	146
Flat-Rolled
Segment Reporting Information [Line Items]
Revenues	1,728	2,277	5,199	7,221
(Loss) Earnings from investees	(3)	30	(15)	63
Earnings (loss) before interest and income taxes	(159)	46	(523)	275
USSE
Segment Reporting Information [Line Items]
Revenues	495	518	1,403	1,933
(Loss) Earnings from investees	0	0	0	0
Earnings (loss) before interest and income taxes	13	(46)	(27)	(27)
Tubular
Segment Reporting Information [Line Items]
Revenues	96	262	533	921
(Loss) Earnings from investees	0	1	3	5
Earnings (loss) before interest and income taxes	(52)	(25)	(147)	(21)
Total reportable segments
Segment Reporting Information [Line Items]
Revenues	2,319	3,057	7,135	10,075
(Loss) Earnings from investees	(3)	31	(12)	68
Earnings (loss) before interest and income taxes	(198)	(25)	(697)	227
Other Businesses
Segment Reporting Information [Line Items]
Revenues	21	12	44	38
(Loss) Earnings from investees	(28)	0	(66)	0
Earnings (loss) before interest and income taxes	(13)	8	(33)	26
Reconciling Items and Eliminations
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
(Loss) Earnings from investees	0	0	0	0
Earnings (loss) before interest and income taxes	0	(63)	(388)	(107)
Net Sales
Segment Reporting Information [Line Items]
Revenues	2,340	3,069	7,179	10,113
Net Sales | Flat-Rolled
Segment Reporting Information [Line Items]
Revenues	1,799	2,363	5,374	7,471
Net Sales | USSE
Segment Reporting Information [Line Items]
Revenues	496	521	1,406	1,942
Net Sales | Tubular
Segment Reporting Information [Line Items]
Revenues	96	263	539	925
Net Sales | Total reportable segments
Segment Reporting Information [Line Items]
Revenues	2,391	3,147	7,319	10,338
Net Sales | Other Businesses
Segment Reporting Information [Line Items]
Revenues	44	40	114	126
Net Sales | Reconciling Items and Eliminations
Segment Reporting Information [Line Items]
Revenues	(95)	(118)	(254)	(351)
Intersegment Sales
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Intersegment Sales | Flat-Rolled
Segment Reporting Information [Line Items]
Revenues	71	86	175	250
Intersegment Sales | USSE
Segment Reporting Information [Line Items]
Revenues	1	3	3	9
Intersegment Sales | Tubular
Segment Reporting Information [Line Items]
Revenues	0	1	6	4
Intersegment Sales | Total reportable segments
Segment Reporting Information [Line Items]
Revenues	72	90	184	263
Intersegment Sales | Other Businesses
Segment Reporting Information [Line Items]
Revenues	23	28	70	88
Intersegment Sales | Reconciling Items and Eliminations
Segment Reporting Information [Line Items]
Revenues	$ (95)	$ (118)	$ (254)	$ (351)

Segment Information - Schedule

Segment Information - Schedule of Reconciling Items to Income (Loss) from Operations (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other items not allocated to segment
Total reconciling items	$ (211)	$ (80)	$ (1,118)	$ 146
Reconciling Items and Eliminations
Other items not allocated to segment
Total reconciling items	0	(63)	(388)	(107)
Reconciling Items and Eliminations | Asset impairment charges (Notes 1 and 9)
Other items not allocated to segment
Total reconciling items	0	0	(263)	0
Reconciling Items and Eliminations | Restructuring and other charges (Note 20)
Other items not allocated to segment
Total reconciling items	0	(54)	(130)	(54)
Reconciling Items and Eliminations | UPI | Gain on previously held investment in UPI
Other items not allocated to segment
Total reconciling items	0	0	25	0
Reconciling Items and Eliminations | Tubular products | Tubular inventory impairment charge
Other items not allocated to segment
Total reconciling items	0	0	(24)	0
Reconciling Items and Eliminations | Clairton | December 24, 2018 Clairton coke making facility fire
Other items not allocated to segment
Total reconciling items	$ 0	$ (9)	$ 4	$ (53)

Acquisition - Narrative (Detail

Acquisition - Narrative (Details) - USD ($) $ in Millions	Feb. 29, 2020	Sep. 30, 2020
Energy Contract
Business Acquisition [Line Items]
Useful Lives		10 years
USS-POSCO Industries (UPI)
Business Acquisition [Line Items]
Ownership interest acquired	50.00%
Purchase price, net of cash acquired	$ 3
Cash received in acquisition	2
UPI accounts payable for substrate purchased from U. S. Steel	135
Fair value of investment	5
Remeasurement gain	25
Receivables	44
Inventories	96
Accounts Payable And Accrued Liabilities	19
Current portion of long-term debt	55
Payroll and Employee Benefit Liabilities	78
Property, plant and equipment	97
Step-up to fair value for property, plant and equipment	47
Step-up to fair value for intangible asset for a beneficial energy contract	$ 54
USS-POSCO Industries (UPI) | Energy Contract
Business Acquisition [Line Items]
Useful Lives	10 years

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue by Product (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 2,340	$ 3,069	$ 7,179	$ 10,113
Semi-finished
Disaggregation of Revenue [Line Items]
Revenues	5	71	65	289
Hot-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	432	736	1,524	2,800
Cold-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	598	686	1,609	2,160
Coated sheets
Disaggregation of Revenue [Line Items]
Revenues	1,011	996	2,866	3,088
Tubular products
Disaggregation of Revenue [Line Items]
Revenues	102	268	551	934
All Other
Disaggregation of Revenue [Line Items]
Revenues	192	312	564	842
Flat-Rolled
Disaggregation of Revenue [Line Items]
Revenues	1,728	2,277	5,199	7,221
Flat-Rolled | Semi-finished
Disaggregation of Revenue [Line Items]
Revenues	5	69	63	278
Flat-Rolled | Hot-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	239	537	980	1,982
Flat-Rolled | Cold-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	555	627	1,495	1,931
Flat-Rolled | Coated sheets
Disaggregation of Revenue [Line Items]
Revenues	778	765	2,202	2,309
Flat-Rolled | Tubular products
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Flat-Rolled | All Other
Disaggregation of Revenue [Line Items]
Revenues	151	279	459	721
USSE
Disaggregation of Revenue [Line Items]
Revenues	495	518	1,403	1,933
USSE | Semi-finished
Disaggregation of Revenue [Line Items]
Revenues	0	2	2	11
USSE | Hot-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	193	199	544	818
USSE | Cold-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	43	59	114	229
USSE | Coated sheets
Disaggregation of Revenue [Line Items]
Revenues	233	231	664	779
USSE | Tubular products
Disaggregation of Revenue [Line Items]
Revenues	11	11	31	31
USSE | All Other
Disaggregation of Revenue [Line Items]
Revenues	15	16	48	65
Tubular
Disaggregation of Revenue [Line Items]
Revenues	96	262	533	921
Tubular | Semi-finished
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Tubular | Hot-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Tubular | Cold-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Tubular | Coated sheets
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Tubular | Tubular products
Disaggregation of Revenue [Line Items]
Revenues	91	257	520	903
Tubular | All Other
Disaggregation of Revenue [Line Items]
Revenues	5	5	13	18
Other Businesses
Disaggregation of Revenue [Line Items]
Revenues	21	12	44	38
Other Businesses | Semi-finished
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Other Businesses | Hot-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Other Businesses | Cold-rolled sheets
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Other Businesses | Coated sheets
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Other Businesses | Tubular products
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
Other Businesses | All Other
Disaggregation of Revenue [Line Items]
Revenues	$ 21	$ 12	$ 44	$ 38

Cash, Cash Equivalents and Re_3

Cash, Cash Equivalents and Restricted Cash - Schedule of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 1,696	$ 749	$ 476
Restricted cash in other current assets	2		0
Restricted cash in other noncurrent assets	89	188	20
Total cash, cash equivalents and restricted cash	$ 1,787	$ 939	$ 496	$ 1,040

Inventories - Inventory Disclos

Inventories - Inventory Disclosure (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 465	$ 628
Semi-finished products	557	720
Finished products	320	376
Supplies and sundry items	56	61
Total	$ 1,398	$ 1,785

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Inventory Disclosure [Abstract]
Percent of Last-in, First-out (LIFO) inventory to total inventory values	72.00%		72.00%		75.00%
Estimate in excess of current acquisition costs over stated inventory values	$ 802		$ 802		$ 735
Cost of sales increase/reduction, liquidations of LIFO inventories	11	$ 12	5	$ 5
Land held for residential or commercial development	$ 37		$ 37		$ 40

Intangible Assets - Amortizable

Intangible Assets - Amortizable Intangible Assets (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 222	$ 168
Accumulated Impairment (a)	67
Accumulated Amortization	99	93
Net Amount	$ 56	75
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Lives	22 years
Gross Carrying Amount	$ 132	132
Accumulated Impairment (a)	55
Accumulated Amortization	77	76
Net Amount	0	56
Patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	22	22
Accumulated Impairment (a)	7
Accumulated Amortization	10	8
Net Amount	$ 5	14
Patents | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Lives	10 years
Patents | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Lives	15 years
Energy Contract
Finite-Lived Intangible Assets [Line Items]
Useful Lives	10 years
Gross Carrying Amount	$ 54	0
Accumulated Impairment (a)	0
Accumulated Amortization	3	0
Net Amount	51	0
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	14	14
Accumulated Impairment (a)	5
Accumulated Amortization	9	9
Net Amount	$ 0	$ 5
Other | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful Lives	4 years
Other | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful Lives	20 years

Intangible Assets - Additional

Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Indefinite-lived Intangible Assets [Line Items]
Estimated amortization expense for the remainder of 2020	$ 2
Estimated amortization expense for 2021	6
Estimated amortization expense for 2022	6
Estimated amortization expense for 2023	6
Estimated amortization expense for 2024	6
Estimated amortization expense for 2025	6
Estimated amortization expense for thereafter	24
Use Rights
Indefinite-lived Intangible Assets [Line Items]
Carrying amount of acquired water rights with indefinite lives	$ 75	$ 75

Pensions and Other Benefits - N

Pensions and Other Benefits - Net Periodic Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 13	$ 11	$ 38	$ 33
Interest cost	49	59	145	178
Expected return on plan assets	(84)	(81)	(249)	(243)
Amortization of prior service cost	0	0	1	1
Amortization of actuarial net loss (gain)	36	33	108	99
Net periodic benefit cost, excluding below	14	22	43	68
Multiemployer plans	19	20	58	57
Settlement, termination and curtailment losses (a)	2	3	10	3
Net periodic benefit cost	35	45	111	128
Pension Benefits | Employee Related Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Settlement, termination and curtailment losses (a)	2	(3)	10	3
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	3	4	9	10
Interest cost	16	22	48	68
Expected return on plan assets	(20)	(19)	(60)	(59)
Amortization of prior service cost	(1)	8	(5)	22
Amortization of actuarial net loss (gain)	(4)	0	(12)	2
Net periodic benefit cost, excluding below	(6)	15	(20)	43
Multiemployer plans	0	0	0	0
Settlement, termination and curtailment losses (a)	0	0	0	0
Net periodic benefit cost	$ (6)	$ 15	$ (20)	$ 43

Pensions and Other Benefits - A

Pensions and Other Benefits - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cash contribution by employer to defined contribution plans	$ 1	$ 12	$ 16	$ 34
Steelworkers Pension Trust
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions, defined benefit plan			57
Other Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions, defined benefit plan			6
Unfunded Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Cash contribution by employer for other postretirement benefits not funded by trusts			$ 37

Stock-Based Compensation Plan_2

Stock-Based Compensation Plans - Summary of Awards Made under Plans (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, other than stock options (in shares)	2,640,690	1,005,500
Grant date fair value per share of awards other than stock options (in dollars per share)	$ 8.82	$ 23.76
Total Shareholder Return (TSR) Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, other than stock options (in shares)	671,390	210,520
Grant date fair value per share of awards other than stock options (in dollars per share)	$ 8.19	$ 29.22
Return On Capital Employed (ROCE) Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, other than stock options (in shares)	0	527,470
Grant date fair value per share of awards other than stock options (in dollars per share)	$ 0	$ 23.90

Stock-Based Compensation Plan_3

Stock-Based Compensation Plans - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense recognized	$ 8	$ 10	$ 20	$ 30
Unrecognized compensation costs related to non-vested stocks	$ 16		$ 16
Weighted average period for recognizing non-vested stock-based compensation costs			16 months
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation plans, award vesting period			3 years
Total Shareholder Return (TSR) Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation plans, award vesting period			3 years
Performance Period Weighting Year One, Year Two, Year Three (Individually)			20.00%
Performance Period Weighting All Three Years			40.00%
Total Shareholder Return (TSR) Performance Awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting of performance awards as percentage to target award			0.00%
Total Shareholder Return (TSR) Performance Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting of performance awards as percentage to target award			200.00%
Return On Capital Employed (ROCE) Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation plans, award vesting period			3 years
Return On Capital Employed (ROCE) Performance Awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting of performance awards as percentage to target award			0.00%
Return On Capital Employed (ROCE) Performance Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting of performance awards as percentage to target award			200.00%
Omnibus Incentive Compensation Plan 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares to be issued	18,200,000		18,200,000
Number of shares available for future grants	5,995,783		5,995,783

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income tax provision (benefit)	$ (24)	$ (44)	$ (48)	$ (43)
Discrete benefit related to accounting exception			39
Expense for an updated estimate to tax reserves related to an unrecognized tax benefit			$ 13

Earnings and Dividends Per Co_3

Earnings and Dividends Per Common Share - Computations for Basic and Diluted Income (Loss) Per Common Share from Continuing Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
(Loss) earnings attributable to United States Steel Corporation stockholders	$ (234)	$ (84)	$ (1,214)	$ 38
Weighted-average shares outstanding (in thousands):
Basic (in shares)	220,402	170,801	188,766	171,882
Effect of Senior Convertible Notes (in shares)	0	0	0	0
Effect of stock options, restricted stock units and performance awards (in shares)	0	0	0	629
Adjusted weighted-average shares outstanding, diluted (in shares)	220,402	170,801	188,766	172,511
Basic (loss) earnings per common share (in dollars per share)	$ (1.06)	$ (0.49)	$ (6.43)	$ 0.22
Diluted (loss) earnings per common share (in dollars per share)	$ (1.06)	$ (0.49)	$ (6.43)	$ 0.22

Earnings and Dividends Per Co_4

Earnings and Dividends Per Common Share - Additional Information (Details) - $ / shares shares in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Quarterly dividend per common share (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.05	$ 0.05	$ 0.05
Securities Granted under the Ominibus Plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from the computation of diluted EPS (in shares)	5,700			4,300			5,500	3,300

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Notional Amounts of Outstanding Derivative Positions (Detail) - Cash flow hedges MMBTU in Thousands, € in Millions, $ in Millions	Sep. 30, 2020EUR (€)MMBTUT	Sep. 30, 2020CAD ($)MMBTUT	Sep. 30, 2019EUR (€)TMMBTU	Sep. 30, 2019CAD ($)TMMBTU
Foreign exchange forwards
Derivative [Line Items]
Notional amount of derivatives	€ 240	$ 8	€ 316	$ 33
Natural gas (in mmbtus) | Commodity purchase swaps
Derivative [Line Items]
Quantities of derivatives held | MMBTU	34,222	34,222	56,873	56,873
Tin (in metric tons) | Commodity purchase swaps
Derivative [Line Items]
Quantities of derivatives held	787	787	530	530
Zinc (in metric tons) | Commodity purchase swaps
Derivative [Line Items]
Quantities of derivatives held	8,148	8,148	14,561	14,561
Electricity (in megawatt hours) | Commodity purchase swaps
Derivative [Line Items]
Quantities of derivatives held	847,680	847,680	0	0

Derivative Instruments - Sche_2

Derivative Instruments - Schedule of Effect of Hedge Accounting on Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Hedge ineffectiveness	$ 1	$ 1	$ 1	$ 1
Commodity purchase swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives in AOCI	19	(6)	30	(2)
Foreign exchange forwards
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives in AOCI	(9)	3	(8)	4
Cost of sales | Commodity purchase swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in income	(6)	(4)	(26)	(14)
Cost of sales | Foreign exchange forwards
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in income	$ (3)	$ 0	$ (2)	$ 0

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Accounts Receivable | Cash flow hedges
Derivative [Line Items]
Derivative Instruments in Hedges, Assets, at Fair Value		$ 8		$ 1
Accounts Payable | Cash flow hedges
Derivative [Line Items]
Derivative Instruments in Hedges, Liabilities, at Fair Value		$ 13		$ 18
Foreign exchange forwards | Maximum
Derivative [Line Items]
Derivatives, term of contract		12 months
Commodity purchase swaps | Designated as Hedging Instrument
Derivative [Line Items]
Derivatives, term of contract		15 months
Commodity purchase swaps | Not Designated as Hedging Instrument
Derivative [Line Items]
Derivatives, term of contract		28 months
Cost of sales
Derivative [Line Items]
Derivative in AOCI to be recognized in income within 1 year		$ 5
Other Financial Costs | Foreign exchange forwards
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 11		$ 18

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Debt and capital lease obligation	$ 5,126,000,000	$ 3,779,000,000
Less unamortized discount and debt issuance costs	236,000,000	138,000,000
Less short-term debt and long-term debt due within one year	262,000,000	14,000,000
Long-term debt	$ 4,628,000,000	3,627,000,000
2037 Senior Notes
Debt Instrument [Line Items]
Interest rate	6.65%
Debt and capital lease obligation	$ 350,000,000	350,000,000
2026 Senior Notes
Debt Instrument [Line Items]
Interest rate	6.25%
Debt and capital lease obligation	$ 650,000,000	650,000,000
2026 Senior Convertible Notes
Debt Instrument [Line Items]
Interest rate	5.00%
Debt and capital lease obligation	$ 350,000,000	350,000,000
2025 Senior Notes
Debt Instrument [Line Items]
Interest rate	6.875%
Debt and capital lease obligation	$ 750,000,000	750,000,000
2025 Senior Secured Notes
Debt Instrument [Line Items]
Interest rate	12.00%
Debt and capital lease obligation	$ 1,056,000,000	0
Export-Import Credit Agreement
Debt Instrument [Line Items]
Interest rate description	Variable
Debt and capital lease obligation	$ 250,000,000	0
Environmental Revenue Bonds
Debt Instrument [Line Items]
Debt and capital lease obligation	$ 620,000,000	620,000,000
Environmental Revenue Bonds | Minimum
Debt Instrument [Line Items]
Interest rate	4.875%
Environmental Revenue Bonds | Maximum
Debt Instrument [Line Items]
Interest rate	6.75%
Fairfield Caster Lease
Debt Instrument [Line Items]
Debt and capital lease obligation	$ 17,000,000	18,000,000
Other finance leases and all other obligations
Debt Instrument [Line Items]
Debt and capital lease obligation	$ 69,000,000	48,000,000
ECA Credit Agreement
Debt Instrument [Line Items]
Interest rate description	Variable
Debt and capital lease obligation	$ 104,000,000	0
Credit Facility Agreement, $2.0 billion
Debt Instrument [Line Items]
Interest rate description	Variable
Debt and capital lease obligation	$ 500,000,000	600,000,000
Maximum borrowing capacity on credit facility	$ 2,000,000,000
UPI Amended Credit Facility
Debt Instrument [Line Items]
Interest rate description	Variable
Debt and capital lease obligation	$ 0	0
USSK Credit Agreement
Debt Instrument [Line Items]
Interest rate description	Variable
Debt and capital lease obligation	$ 410,000,000	393,000,000
USSK Credit Facilities
Debt Instrument [Line Items]
Interest rate description	Variable
Debt and capital lease obligation	$ 0	$ 0

Debt - Summary of Debt Instrume

Debt - Summary of Debt Instrument Redemption Percentages (Details) - Secured Debt - 2025 Senior Secured Notes	May 29, 2020
2022
Debt Instrument [Line Items]
Redemption price percentage	106.00%
2023
Debt Instrument [Line Items]
Redemption price percentage	103.00%
2024 and thereafter
Debt Instrument [Line Items]
Redemption price percentage	100.00%

Debt - Additional Information (

Debt - Additional Information (Detail)	Sep. 30, 2020USD ($)	May 29, 2020USD ($)	Feb. 19, 2020	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2021	Jun. 30, 2021	Sep. 30, 2020EUR (€)
Debt Instrument [Line Items]
Borrowing proceeds, net of transaction fees				$ 240,000,000	$ 0
2025 Senior Secured Notes
Debt Instrument [Line Items]
Interest rate	12.00%			12.00%				12.00%
2025 Senior Secured Notes | Secured Debt
Debt Instrument [Line Items]
Aggregate principal amount		$ 1,056,000,000
Interest rate		12.00%
Issuance price as a percent of face value		94.665%
Net proceeds from the offering, after fees related to underwriting and third party expenses		$ 977,000,000
Fees related to underwriting and third party expenses		$ 23,000,000
Conditional percentage repurchase price		100.00%
2025 Senior Secured Notes | Secured Debt | Prior to June 1, 2022
Debt Instrument [Line Items]
Percent of the original aggregate principal amount that may be redeemed (up to)		35.00%
Redemption price percentage		112.00%
ECA Credit Agreement
Debt Instrument [Line Items]
Amounts drawn on credit facility	$ 104,000,000			$ 104,000,000
Long-term Line Of Credit, Payment Period			6 months
Credit Facility Agreement, $2.0 billion
Debt Instrument [Line Items]
Maximum borrowing capacity on credit facility	2,000,000,000			2,000,000,000
Amounts drawn on credit facility	500,000,000			500,000,000
Capacity available for purposes other than trade purchases	200,000,000			200,000,000
Capacity available for trade purchases	294,000,000			294,000,000
Available borrowing capacity	$ 1,006,000,000			$ 1,006,000,000
Length debt maturity could be extended if liquidity conditions are not met				91 days
Credit Facility Agreement, $2.0 billion | Covenant Requirement
Debt Instrument [Line Items]
Fixed Charge Coverage Ratio Minimum	1			1				1
Fixed Charge Coverage Ratio Maximum	1			1				1
Percentage of total aggregate commitments, upper range under financial covenant	10.00%			10.00%				10.00%
Credit Agreement, upper range of outstanding debt	$ 200,000,000			$ 200,000,000
Maximum | ECA Credit Agreement
Debt Instrument [Line Items]
Long-term Line Of Credit, Payment Period			8 years
Maximum | Change in control event
Debt Instrument [Line Items]
Obligations under financing arrangements	4,420,000,000			4,420,000,000
Maximum | Fairfield slab caster
Debt Instrument [Line Items]
Obligations under financing arrangements	17,000,000			17,000,000
Line of Credit | Export-Import Credit Agreement
Debt Instrument [Line Items]
Borrowing proceeds, net of transaction fees	240,000,000
Transaction fees paid	10,000,000
Maximum borrowing capacity on credit facility	$ 250,000,000			$ 250,000,000
Eligibility threshold for extension option	95.00%			95.00%				95.00%
Line of Credit | Export-Import Credit Agreement | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate	2.50%
Revolving Credit Facility | USSK Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity on credit facility	$ 539,000,000			$ 539,000,000				€ 460,000,000
Amounts drawn on credit facility	410,000,000			410,000,000				350,000,000
Revolving Credit Facility | USSK Credit Agreement | Subsequent Event
Debt Instrument [Line Items]
Net Debt to EBIDTA Ratio Maximum						3.5	6.5
Revolving Credit Facility | USSK Credit Facilities
Debt Instrument [Line Items]
Maximum borrowing capacity on credit facility	35,000,000			35,000,000
Amounts drawn on credit facility	0			0
Available borrowing capacity	33,000,000			33,000,000
Customs and other guarantees outstanding	$ 2,000,000			$ 2,000,000
Revolving Credit Facility | USSK €20 Million Unsecured Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity on credit facility | €								20,000,000
Revolving Credit Facility | USSK €10 Million Unsecured Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity on credit facility | €								€ 10,000,000

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Schedule of the Change in Fair Value by Option (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value Mark to Market gain/(loss)	$ 40
Call Option
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value asset/(liability)	70	$ 166
Fair Value Mark to Market gain/(loss)	(96)
Common Class B | Call Option
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value asset/(liability)	(1)	(2)
Fair Value Mark to Market gain/(loss)	1
Common Class B | Put Option
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value asset/(liability)	(57)	$ (192)
Fair Value Mark to Market gain/(loss)	$ 135

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Financial Assets and Liabilities Not Carried at Fair Value (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Fair Value
Financial liabilities:
Short-term and long-term debt (a)	$ 4,448	$ 3,576
Carrying Amount
Financial liabilities:
Short-term and long-term debt (a)	$ 4,804	$ 3,575

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Additional Information (Details) $ in Millions	Apr. 30, 2020USD ($)installment	Sep. 30, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net change in fair value of options		$ 34		$ 40
Installment payments received to-date				$ 55	$ 0
Stelco [Member] | Minntac Mine
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest offered in option	25.00%
Aggregate consideration for option	$ 100
Number of installment payments | installment	5
Consideration per installment	$ 20
Additional contribution to Joint Venture upon exercise	$ 500
Installment payments received to-date			$ 60

Statement of Changes in Stock_3

Statement of Changes in Stockholders' Equity (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of year	$ 3,654	$ 3,726	$ 4,093	$ 4,312	$ 4,236	$ 4,203	$ 4,093	$ 4,203
Comprehensive income (loss):
Net (loss) earnings	(234)	(589)	(391)	(84)	68	54	(1,214)	38
Other comprehensive income (loss), net of tax:
Pension and other benefit adjustments	16	29	52	30	32	32	97	94
Currency translation adjustment	34	20	(23)	(40)	12	(17)	31	(45)
Derivative financial instruments	8	15	(5)	(2)	(11)	15	18	2
Employee stock plans	10	8	2	11	12	2
Common Stock Issued		410
Common stock repurchased				(18)	(28)	(42)
Dividends paid on common stock	(3)	(1)	(2)	(8)	(9)	(9)
Stelco Option Agreement	18	37
Other	1	(1)		(1)
Cumulative effect upon adoption of lease accounting standard						(2)
Ending balance	3,504	3,654	3,726	4,200	4,312	4,236	3,504	4,200
Retained Earnings (Accumulated Deficit)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of year	(438)	151	544	1,314	1,255	1,212	544	1,212
Comprehensive income (loss):
Net (loss) earnings	(234)	(589)	(391)	(84)	68	54
Other comprehensive income (loss), net of tax:
Dividends paid on common stock	0	0	(2)	(8)	(9)	(9)
Other	1			(1)
Cumulative effect upon adoption of lease accounting standard						(2)
Ending balance	(671)	(438)	151	1,221	1,314	1,255	(671)	1,221
Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of year	(390)	(454)	(478)	(963)	(996)	(1,026)	(478)	(1,026)
Other comprehensive income (loss), net of tax:
Pension and other benefit adjustments	16	29	52	30	32	32
Currency translation adjustment	34	20	(23)	(40)	12	(17)
Derivative financial instruments	8	15	(5)	(2)	(11)	15
Ending balance	(332)	(390)	(454)	(975)	(963)	(996)	(332)	(975)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of year	229	179	179	179	178	177	179	177
Other comprehensive income (loss), net of tax:
Employee stock plans	0	0	0	0	1	1
Common Stock Issued		50
Ending balance	229	229	179	179	179	178	229	179
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of year	(175)	(175)	(173)	(155)	(126)	(78)	(173)	(78)
Other comprehensive income (loss), net of tax:
Employee stock plans	0	0	(2)	0	(1)	(6)
Common stock repurchased				(18)	(28)	(42)
Ending balance	(175)	(175)	(175)	(173)	(155)	(126)	(175)	(173)
Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of year	4,391	4,024	4,020	3,936	3,924	3,917	4,020	3,917
Other comprehensive income (loss), net of tax:
Employee stock plans	10	8	4	11	12	7
Common Stock Issued		360
Dividends paid on common stock	(3)	(1)
Ending balance	4,398	4,391	4,024	3,947	3,936	3,924	4,398	3,947
Non- Controlling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of year	37	1	1	1	1	1	1	1
Other comprehensive income (loss), net of tax:
Stelco Option Agreement	18	37
Other		(1)
Ending balance	$ 55	$ 37	$ 1	$ 1	$ 1	$ 1	$ 55	$ 1

Reclassifications from Accumu_3

Reclassifications from Accumulated Other Comprehensive Income (AOCI) - Other Comprehensive Income Activity Net of Tax (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance			$ (478)	$ (1,026)
Other comprehensive income (loss) before reclassifications			31	(60)
Amounts reclassified from AOCI			115	111
Total other comprehensive income (loss), net of tax	$ 58	$ (12)	146	51
Ending Balance	(332)	(975)	(332)	(975)
Pension and Other Benefit Items
Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance			(843)	(1,416)
Other comprehensive income (loss) before reclassifications			6	(3)
Amounts reclassified from AOCI			91	97
Total other comprehensive income (loss), net of tax			97	94
Ending Balance	(746)	(1,322)	(746)	(1,322)
Foreign Currency Items
Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance			381	403
Other comprehensive income (loss) before reclassifications			31	(45)
Amounts reclassified from AOCI			0	0
Total other comprehensive income (loss), net of tax			31	(45)
Ending Balance	412	358	412	358
Unrealized Gain (Loss) on Derivatives
Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance			(16)	(13)
Other comprehensive income (loss) before reclassifications			(6)	(12)
Amounts reclassified from AOCI			24	14
Total other comprehensive income (loss), net of tax			18	2
Ending Balance	$ 2	$ (11)	$ 2	$ (11)

Reclassifications from Accumu_4

Reclassifications from Accumulated Other Comprehensive Income (AOCI) - Defined Benefit Plan In Other Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Amortization of pension and other benefit items
Total before tax	$ (258)			$ (128)			$ (1,262)	$ (5)
Tax provision	24			44			48	43
Net of tax	(234)	$ (589)	$ (391)	(84)	$ 68	$ 54	(1,214)	38
Amount reclassified from AOCI (a)
Amortization of pension and other benefit items
Total before tax	39			49			145	146
Tax provision	(15)			(12)			(30)	(35)
Net of tax	24			37			115	111
Pension and Other Benefit Items | Amount reclassified from AOCI (a)
Amortization of pension and other benefit items
Prior service costs (a)	(1)			8			(4)	23
Actuarial losses (a)	32			33			96	101
Settlement, termination and curtailment losses (a)	2			3			2	3
UPI Purchase Accounting Adjustment	0			0			23	0
Total pensions and other benefits items	33			44			117	127
Unrealized Gain (Loss) on Derivatives | Amount reclassified from AOCI (a)
Amortization of pension and other benefit items
Derivative reclassifications to Condensed Consolidated Statements of Operations	$ 6			$ 5			$ 28	$ 19

Transactions with Related Par_2

Transactions with Related Parties - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Feb. 29, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Net sales to related parties	$ 268	$ 367	$ 710	$ 1,112
Accounts payable to related parties	113		113			$ 84
USS-POSCO Industries (UPI)
Related Party Transaction [Line Items]
UPI accounts payable for substrate purchased from U. S. Steel					$ 135
Outside processing services
Related Party Transaction [Line Items]
Purchases from related parties	9	7	47	23
Taconite pellets
Related Party Transaction [Line Items]
Purchases from related parties	19	$ 27	53	$ 78
PRO-TEC Coating Company
Related Party Transaction [Line Items]
Accounts payable to related parties	109		109			82
Other equity investees
Related Party Transaction [Line Items]
Accounts payable to related parties	$ 4		$ 4			$ 2

Restructuring and Other Charg_3

Restructuring and Other Charges - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Additional charges	$ 0	$ 54	$ 130	$ 54
Cash payments for restructuring			134
Business Exit and Employee Severance
Restructuring Cost and Reserve [Line Items]
Cash payments for restructuring			130
Business Exit and Employee Severance | Postretirement Benefit Trust (VEBA)
Restructuring Cost and Reserve [Line Items]
Cash payments for restructuring			29
Keetac Mining and Great Lakes Works Restructuring
Restructuring Cost and Reserve [Line Items]
Additional charges			72
Lorain Tubular Operations and Lone Star Tubular Operations Restructuring
Restructuring Cost and Reserve [Line Items]
Additional charges			13
Company Wide Headcount Reductions
Restructuring Cost and Reserve [Line Items]
Additional charges			13
Voluntary Early Retirement Program
Restructuring Cost and Reserve [Line Items]
Additional charges			$ 32

Restructuring and Other Charg_4

Restructuring and Other Charges - Schedule of Accrued Balances From Restructuring and Other Charges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Reserve [Roll Forward]
Balance at December 31, 2019			$ 212
Additional charges	$ 0	$ 54	130	$ 54
Cash payments/utilization			(134)
Balance at September 30, 2020	208		208
Employee Related Costs
Restructuring Reserve [Roll Forward]
Balance at December 31, 2019			87
Additional charges			75
Cash payments/utilization			(93)
Balance at September 30, 2020	69		69
Exit Costs
Restructuring Reserve [Roll Forward]
Balance at December 31, 2019			125
Additional charges			51
Cash payments/utilization			(37)
Balance at September 30, 2020	139		139
Non - Cash Charges
Restructuring Reserve [Roll Forward]
Balance at December 31, 2019			0
Additional charges			4
Cash payments/utilization			(4)
Balance at September 30, 2020	$ 0		$ 0

Restructuring and Other Charg_5

Restructuring and Other Charges - Schedule of Accrued Liabilities for Restructuring on Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Accrued liabilities for restructuring and other reduction programs	$ 208	$ 212
Accounts Payable
Restructuring Cost and Reserve [Line Items]
Accrued liabilities for restructuring and other reduction programs	47	46
Payroll and benefits payable
Restructuring Cost and Reserve [Line Items]
Accrued liabilities for restructuring and other reduction programs	38	64
Employee benefits
Restructuring Cost and Reserve [Line Items]
Accrued liabilities for restructuring and other reduction programs	30	23
Deferred credits and other noncurrent liabilities
Restructuring Cost and Reserve [Line Items]
Accrued liabilities for restructuring and other reduction programs	$ 93	$ 79

Contingencies and Commitments -

Contingencies and Commitments - Asbestos Litigation Activity (Details) - Asbestos Matters	9 Months Ended		12 Months Ended
	Sep. 30, 2020LegalMatter	Sep. 30, 2020Claim_Group	Dec. 31, 2019Claim_Group	Dec. 31, 2018Claim_Group	Dec. 31, 2017Claim_Group
Loss Contingency Accrual [Roll Forward]
Opening Number of Claims		2,390	2,320	3,315	3,340
Claims Dismissed, Settled and Resolved (a)		185	195	1,285	275
New Claims		230	265	290	250
Closing Number of Claims	1,540	2,435	2,390	2,320	3,315
Number of claims dismissed				1,000

Contingencies and Commitments_2

Contingencies and Commitments - Changes in Accrued Liabilities for Remediation Activities (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)
Change in Accrued Liabilities for Remediation Activities [Roll Forward]
Beginning of period	$ 186
Accruals for environmental remediation deemed probable and reasonably estimable	5
Obligations settled	(29)
End of period	$ 162

Contingencies and Commitments_3

Contingencies and Commitments - Accrued Liabilities for Remediation Activities Included in Balance Sheet (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Total	$ 162	$ 186
Accounts Payable
Loss Contingencies [Line Items]
Total	52	53
Deferred credits and other noncurrent liabilities
Loss Contingencies [Line Items]
Total	$ 110	$ 133

Contingencies and Commitments_4

Contingencies and Commitments - Payments for Contracts with Remaining Terms in Excess of One Year (Detail) $ in Millions	Sep. 30, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2020	$ 162
2021	694
2022	621
2023	386
2024	163
Later Years	832
Total	$ 2,858

Contingencies and Commitments_5

Contingencies and Commitments - Additional Information (Detail) € in Millions, Allowances in Millions

3 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2020USD ($)LegalMatter

Sep. 30, 2019USD ($)

Sep. 30, 2020USD ($)LegalMatterAllowancesPlaintiff

Sep. 30, 2020EUR (€)LegalMatterAllowancesPlaintiff

Sep. 30, 2019USD ($)

Dec. 31, 2019USD ($)Claim_GroupPlaintiffLegalMatter

Sep. 30, 2020

Sep. 30, 2020Claim_Group

Sep. 30, 2020USD ($)

Sep. 30, 2020Project

Sep. 30, 2020Allowances

Dec. 31, 2018Claim_Group

Dec. 31, 2017Claim_Group

Dec. 31, 2016Claim_Group

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

$ 186,000,000

$ 162,000,000

Accrued liabilities for post-closure site monitoring and other costs

23,000,000

Accrued liability for administrative and legal costs

11,000,000

Number of years of projected administrative and legal costs included in accrual

3 years

3 years

Capital expenditures

$ 8,000,000

$ 40,000,000

Final allocation for emissions allowances | Allowances

48

48

Emissions allowances purchased | Allowances

12.3

Cost of emissions allowances purchased

$ 165,200,000

€ 141.1

Estimated Shortfall in Emissions Allowances | Allowances

12.2

12.2

Estimated capital expenditures of complying with BAT over 2017 to 2020 period

$ 161,600,000

€ 138

Financial assurance guarantees, maximum

7,000,000

Residual value of equipment

23,000,000

Residual value liability

0

Restricted cash

$ 190,000,000

91,000,000

Contract commitments to acquire property, plant and equipment

730,000,000

Maximum default payment on termination of agreement

117,000,000

Total payment under take-or-pay contracts

$ 123,000,000

$ 167,000,000

$ 425,000,000

$ 493,000,000

Minimum

Loss Contingencies [Line Items]

Projected percentage remediation costs may exceed accrued liabilities

20.00%

20.00%

Unconditional purchase obligation term

2 years

2 years

Maximum

Loss Contingencies [Line Items]

Projected percentage remediation costs may exceed accrued liabilities

30.00%

30.00%

Unconditional purchase obligation term

16 years

16 years

Asbestos Matters

Loss Contingencies [Line Items]

Active cases brought against U.S. Steel | LegalMatter

850

850

850

800

Number of plaintiffs involved | Plaintiff

2,435

2,435

2,390

Number of claims pending in jurisdictions

1,540

1,540

1,540

2,390

2,435

2,320

3,315

3,340

Percentage of claims pending in jurisdictions

63.00%

Projects with Ongoing Study and Scope Development

Loss Contingencies [Line Items]

Environmental remediation projects | Project

5

Accrued liabilities for remediation activities

1,000,000

Projects with Ongoing Study and Scope Development | Minimum

Loss Contingencies [Line Items]

Environment exit costs, possible additional loss

$ 25,000,000

Projects with Ongoing Study and Scope Development | Maximum

Loss Contingencies [Line Items]

Environment exit costs, possible additional loss

$ 40,000,000

Significant Projects with Defined Scope

Loss Contingencies [Line Items]

Environmental remediation projects | Project

4

Accrued liabilities for remediation activities

105,000,000

Significant Projects with Defined Scope | Minimum

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

5,000,000

Gary Works, Project with Defined Scope

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

27,000,000

Geneva Project

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

26,000,000

Cherryvale Zinc Site

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

8,000,000

St Louis Estuary Project

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

44,000,000

Environmental Remediation Other Projects

Loss Contingencies [Line Items]

Environmental remediation projects | Project

2

Accrued liabilities for remediation activities

3,000,000

Environmental Remediation Other Projects | Minimum

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

1,000,000

Environmental Remediation Other Projects | Maximum

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

5,000,000

Environmental Remediation Projects Less Than One Million

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

3,000,000

Environmental Remediation Projects Less Than One Million | Maximum

Loss Contingencies [Line Items]

Accrued liabilities for remediation activities

1,000,000

Surety Bonds

Loss Contingencies [Line Items]

Financial assurance guarantees, maximum

$ 210,000,000

Significant Equity Investment_2

Significant Equity Investments Summarized Information for Significant Equity Investments (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Net sales	$ 1,087	$ 1,857
Cost of sales	983	1,624
Operating income	36	190
Net earnings	5	172
Net earnings attributable to significant equity investments	$ 5	$ 172

Significant Equity Investment_3

Significant Equity Investments - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Percentage Of Investee Financial Information			100.00%	100.00%
Income from significant equity investments	$ (31)	$ 31	$ (78)	$ 68
Significant Equity Investments
Schedule of Equity Method Investments [Line Items]
Income from significant equity investments			$ (11)	$ 66

Common Stock Repurchase Progr_2

Common Stock Repurchase Program - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 22, 2020	Sep. 30, 2020	Sep. 30, 2019
Subsidiary, Sale of Stock [Line Items]
Net proceeds from public offering of common stock (Note 23)		$ 410	$ 0
Treasury Stock, Shares, Acquired			5,289,475
Treasury Stock, Value, Acquired, Cost Method			$ 88
Public Offering
Subsidiary, Sale of Stock [Line Items]
Shares issued (in shares)	50,000,000
Par value (in dollars per share)	$ 1
Price per share (in dollars per share)	$ 8.2075
Net proceeds from public offering of common stock (Note 23)	$ 410