Contingencies and Commitments - Additional Information (Detail) In Millions, unless otherwise specified	0 Months Ended	3 Months Ended		6 Months Ended					6 Months Ended										6 Months Ended		6 Months Ended	12 Months Ended	6 Months Ended			3 Months Ended		6 Months Ended					6 Months Ended										6 Months Ended
	Aug. 02, 2012 Facility	Jun. 30, 2013 USD ($) Micron T	Jun. 30, 2012 USD ($)	Jun. 30, 2013 USD ($) Micron T	Jun. 30, 2012 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2013 Randle Reef USD ($)	Jun. 30, 2013 Randle Reef CAD	Jun. 30, 2013 National Government Randle Reef USD ($)	Jun. 30, 2013 National Government Randle Reef CAD	Jun. 30, 2013 Provincial Government Randle Reef USD ($)	Jun. 30, 2013 Provincial Government Randle Reef CAD	Jun. 30, 2013 Local Sources Randle Reef USD ($)	Jun. 30, 2013 Local Sources Randle Reef CAD	Jun. 30, 2013 U. S. Steel Canada Inc. Randle Reef USD ($) T	Jun. 30, 2013 U. S. Steel Canada Inc. Randle Reef CAD	Jun. 30, 2013 Minimum USD ($)	Jun. 30, 2013 Minimum Gateway Energy and Coke Company, LLC	Jun. 30, 2013 Maximum USD ($)	Jun. 30, 2013 Maximum Gateway Energy and Coke Company, LLC	Jun. 30, 2013 Asbestos Matters USD ($) Claim_Group Plaintiff LegalMatter	Dec. 31, 2012 Asbestos Matters USD ($) Plaintiff LegalMatter	Jun. 30, 2013 Asbestos Matters Allege Suffering from Mesothelioma Plaintiff	Jun. 30, 2013 Asbestos Matters Minimum Defendant	Jun. 30, 2013 Asbestos Matters Maximum Defendant	Jun. 30, 2013 Environmental Remediation Expense USD ($)	Jun. 30, 2012 Environmental Remediation Expense USD ($)	Jun. 30, 2013 Environmental Remediation Expense USD ($)	Jun. 30, 2012 Environmental Remediation Expense USD ($)	Jun. 30, 2013 Projects with Ongoing Study and Scope Development USD ($) Project	Jun. 30, 2013 Projects with Ongoing Study and Scope Development Resource Conservation and Recovery Act (RCRA) Programs Project	Jun. 30, 2013 Projects with Ongoing Study and Scope Development Voluntary Remediation Program Project	Jun. 30, 2013 Projects with Ongoing Study and Scope Development Minimum USD ($)	Jun. 30, 2013 Projects with Ongoing Study and Scope Development Maximum USD ($)	Jun. 30, 2013 Gary Works, Project with Defined Scope USD ($)	Jun. 30, 2013 Other Project with Defined Scope Greater Than or Equal to $5 Million USD ($)	Jun. 30, 2013 Other Project with Defined Scope Greater Than or Equal to $5 Million Minimum USD ($)	Jun. 30, 2013 Environmental Remediation Other Projects USD ($) Project	Jun. 30, 2013 Environmental Remediation Other Projects Minimum USD ($)	Jun. 30, 2013 Environmental Remediation Other Projects Maximum USD ($)	Jun. 30, 2013 Environmental Remediation Projects Less Than One Million USD ($)	Jun. 30, 2013 Environmental Remediation Projects Less Than One Million Maximum USD ($)	Jun. 30, 2013 Antitrust Class Actions Defendant	Jun. 30, 2013 Surety Bonds USD ($)	Jun. 30, 2013 Restricted Cash To Fund Certain Capital Projects USD ($)
Loss Contingencies [Line Items]
Asbestos matters																					As of June 30, 2013, U. S. Steel was a defendant in approximately 805 active cases involving approximately 3,345 plaintiffs. Many of these cases involve multiple defendants (typically from fifty to more than one hundred).
Active cases brought against U.S. Steel																					805	790
Number of plaintiffs involved																					3,345	3,330	260
Number of defendants involved																								50	100																		8
Number of facilities that failed to meet certain environmental requirements	3
Number of claims pending in jurisdictions																					2,560
Percentage of claims pending in jurisdictions																					77.00%
Payment in settlement of claims																					$ 5	$ 15
Cases resolved upon payment																					110	190
Number of cases added and resulted in claims																					125	285
Number of major groups																					3
Expenses related to remediation included in cost of sales																										1	6	5	9
Projected percentage remediation costs may exceed accrued liabilities																	20.00%		40.00%
Environmental remediation projects																														6	4	1						6
Accrued liabilities for remediation activities		201		201		203																								23					59	65	5	13	1	5	7	1
Environment exit costs, possible additional loss																																	45	75
Accrued liabilities for post-closure site monitoring and other costs		28		28
Accrued liability for administrative and legal costs		6		6
Number of years of projected administrative and legal costs included in accrual				3 years
Capital expenditures				24	29
Requirements of Environmental Protection Agency				On May 13, 2010, the EPA published its final Greenhouse Gas Tailoring Rule establishing a mechanism for regulating GHG emissions from facilities through the Clean Air Act’s Prevention of Significant Deterioration (PSD) permitting process. U. S. Steel reported its emissions under these rules in accordance with the regulation and its deadlines. Since 2011, new projects that increase GHG emissions by more than 75,000 tons per year have new PSD requirements based on best available control technology (BACT), but only if the project also significantly increases emissions of at least one non-GHG pollutant. Only existing sources with Title V permits or new sources obtaining Title V permits for non-GHG pollutants will also be required to address GHG emissions. As of July 1, 2011, new sources not already subject to Title V requirements that emit over 100,000 tons per year, or modifications to existing permits that increase GHG emissions by more than 75,000 tons per year, are subject to PSD and Title V requirements. On November 17, 2010 the EPA issued its “PSD and Title V Permitting Guidance for Greenhouse Gases” and “Available and Emerging Technologies for Reducing Greenhouse Gas Emissions from the Iron and Steel Industry.” With this guidance, EPA intends to help state and local air permitting authorities identify greenhouse gas reductions under the Clean Air Act. Additionally, the EPA revised the National Ambient Air Quality Standards (NAAQS) for nitrogen oxide, sulfur dioxide and lead in 2010 and is in the process of revising the NAAQS for 2.5 micron particulate matter, ozone and sulfur dioxides.
Minimum annual increment in GHG emission due to modifications to existing permits subject to Title V and PSD requirement if only project significantly increases emissions of at least one non-GHG pollutant		75,000		75,000
Minimum annual emission of new sources subject to PSD and Title V requirement		100,000		100,000
NAAQS micron particulate matter in revision process		2.5		2.5
Estimated capital expenditures of complying with BAT over 2013 to 2016 period																	300		400
Financial assurance guarantees, maximum		29		29																																								166
Regulatory agencies estimate expenditures amount							114	120
Committed contribution									38	40	38	40	38	40
Contributions made during the period, hot rolled steel															11,000	11,000
Contributions made during the period, cash															2	2
Expected date of committed contribution															2014	2014
Liability accrued related to committed contributions															9
Residual value of equipment		16		16
Restricted cash		147		147		181																																							55
Restricted cash current		2		2		5
Contract commitments to acquire property, plant and equipment		215		215
Unconditional purchase obligation term																	2 years		15 years
Percentage of purchase obligation																		90.00%		105.00%
Maximum default payment on termination of agreement		255		255
Total payment under take-or-pay contracts		$ 112	$ 185	$ 295	$ 370