United States Steel (X) 10-K 25 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Dec. 31, 2013	Feb. 20, 2014	Jun. 28, 2013
Document and Entity Information [Abstract]	'	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Trading Symbol	'X	'	'
Entity Registrant Name	'UNITED STATES STEEL CORP	'	'
Entity Central Index Key	'0001163302	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	144,687,528	'
Entity Public Float	'	'	$2.50

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net sales:	'	'	'
Net sales	$16,269	$18,025	$18,626
Net sales to related parties	1,155	1,303	1,258
Total	17,424	19,328	19,884
Operating expenses (income):	'	'	'
Cost of sales (excludes items shown below)	16,016	17,630	18,326
Selling, general and administrative expenses	610	654	733
Depreciation, depletion and amortization	684	661	681
Income from investees	-40	-144	-85
Impairment of goodwill	1,806	0	0
Restructuring and other charges	248	0	0
Net loss (gain) on disposals of assets	0	296	-25
Other income, net	0	-16	-11
Total	19,324	19,081	19,619
(Loss) income from operations	-1,900	247	265
Interest income	-3	-7	-6
Interest expense	266	214	190
Other financial costs	69	34	54
Net interest and other financial costs	332	241	238
(Loss) income before income taxes and noncontrolling interests	-2,232	6	27
Income tax (benefit) provision	-560	131	80
Net loss	-1,672	-125	-53
Less: Net loss attributable to noncontrolling interests	0	-1	0
Net loss attributable to United States Steel Corporation	($1,672)	($124)	($53)
Net loss per share attributable to United States Steel Corporation shareholders:	'	'	'
— Basic (in dollars per share)	($11.56)	($0.86)	($0.37)
— Diluted (in dollars per share)	($11.56)	($0.86)	($0.37)

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Statement of Comprehensive Income [Abstract]	'		'		'
Net loss	($1,672)		($125)		($53)
Other comprehensive income (loss), net of tax:	'		'		'
Changes in foreign currency translation adjustments	30		114		-44
Changes in pension and other employee benefit accounts	1,486	[1]	-15	[1]	-255	[1]
Total other comprehensive income (loss), net of tax	1,516		99		-299
Comprehensive loss including noncontrolling interest	-156		-26		-352
Comprehensive loss attributable to noncontrolling interest	0		-1		0
Comprehensive loss attributable to United States Steel Corporation	-156		-25		-352
Related income tax (provision) benefit:	'		'		'
Pension and other benefits adjustments	($762)		($74)		$52
[1]	Year Ended December 31,(Dollars in millions) 2013 2012 2011Related income tax (provision) benefit: Pension and other benefits adjustments $(762) $(74) $52

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Current assets:	'		'
Cash and cash equivalents	$604		$570
Receivables, less allowance of $53 and $55	1,818		1,862
Receivables from related parties	157		218
Inventories	2,688		2,503
Income tax receivable	185		10
Deferred income tax benefits	576		293
Other current assets	50		40
Total current assets	6,078		5,496
Investments and long-term receivables, less allowance of $3 for both periods (Note 9)	621		609
Property, plant and equipment, net	5,922		6,408
Intangibles — net	271		253
Goodwill	4		1,822
Deferred income tax benefits	16		302
Other noncurrent assets, less allowance of $7 and $0	231		327
Total assets	13,143		15,217
Current liabilities:	'		'
Accounts payable and other accrued liabilities	1,681		1,722
Accounts payable to related parties	73		78
Bank checks outstanding	0		15
Payroll and benefits payable	974		977
Accrued taxes	140		146
Accrued interest	54		50
Short-term debt and current maturities of long-term debt	323		2
Total current liabilities	3,245		2,990
Long-term debt, less unamortized discount	3,616		3,936
Employee benefits	2,064		4,416
Deferred income tax liabilities	445		0
Deferred credits and other noncurrent liabilities	424		397
Total liabilities	9,794		11,739
Contingencies and commitments	'		'
Stockholders’ Equity	'		'
Common stock issued — 150,925,911 shares issued (par value $1 per share, authorized 400,000,000 shares)	151		151
Treasury stock, at cost (6,245,666 shares and 6,643,553 shares)	-480		-521
Additional paid-in capital	3,667		3,652
Retained earnings	1,762		3,463
Accumulated other comprehensive loss	-1,752	[1]	-3,268	[1]
Total United States Steel Corporation stockholders’ equity	3,348		3,477
Noncontrolling interests	1		1
Total liabilities and stockholders’ equity	$13,143		$15,217
[1]	All amounts are net of tax. Amounts in parentheses indicate debits.

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Treasury stock, shares	6,245,666	6,643,553
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	150,925,911	150,925,911
Common stock, par value (usd per share)	$1	$1
Receivables, allowance	$53	$55
Investments and long-term receivables, allowance	3	3
Other noncurrent assets, allowance	$7	$0

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:	'	'	'
Net loss	($1,672)	($125)	($53)
Adjustments to reconcile net cash (used in) provided by operating activities:	'	'	'
Depreciation, depletion and amortization	684	661	681
Impairment of goodwill	1,806	0	0
Non-cash restructuring and other charges	248	0	0
Provision for doubtful accounts	5	-1	3
Pensions and other postretirement benefits	-28	-181	-24
Deferred income taxes	-359	74	-68
Net loss (gain) on disposal of assets	0	296	-25
Currency remeasurement loss/(gain)	7	-15	40
Distributions received, net of equity investees income	-27	-45	-52
Changes in:	'	'	'
Current receivables	114	246	-424
Inventories	-201	192	-460
Current accounts payable and accrued expenses	-61	-103	332
Income taxes receivable/payable	-187	17	133
All other, net	85	119	85
Net cash provided by operating activities	414	1,135	168
Investing activities:	'	'	'
Capital expenditures	-477	-723	-848
Acquisition of intangible assets	-12	0	0
Disposal of assets	3	155	41
Change in restricted cash, net	100	-21	35
Investments, net	-7	-13	-41
Net cash used in investing activities	-393	-602	-813
Financing activities:	'	'	'
Revolving credit facilities - borrowings	0	523	4,715
Revolving credit facilities - repayments	0	-653	-4,570
(Payments on) proceeds from Receivables Purchase Agreement	0	-380	380
Issuance of long-term debt, net of financing costs	575	485	193
Repayment of long-term debt	-542	-319	-216
Receipts from exercise of stock options	0	0	3
Distributions from noncontrolling interests	0	0	1
Dividends paid	-29	-29	-29
Net cash provided by (used in) financing activities	4	-373	477
Effect of exchange rate changes on cash	9	2	-2
Net increase (decrease) in cash and cash equivalents	34	162	-170
Cash and cash equivalents at beginning of year	570	408	578
Cash and cash equivalents at end of year	$604	$570	$408

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)

Total

Comprehensive (Loss) Income

Common stock

Treasury stock

Additional paid-in capital

Retained earnings

Retained earnings

Pension and other benefit adjustments

Pension and other benefit adjustments

Foreign currency translation adjustments

Foreign currency translation adjustments

Accumulated other comprehensive (loss) income

Total stockholders’ equity

Noncontrolling interests

Noncontrolling interests

In Millions, except Share data in Thousands, unless otherwise specified

Comprehensive (Loss) Income

Comprehensive (Loss) Income

Comprehensive (Loss) Income

Comprehensive (Loss) Income

Balance at beginning of year at Dec. 31, 2010

'

'

$151

($580)

$3,650

$3,698

'

($3,343)

'

$275

'

'

'

$1

'

Balance at beginning of year (in shares) at Dec. 31, 2010

'

'

150,926

-7,252

'

'

'

'

'

'

'

'

'

'

'

Increase (Decrease) in Stockholders' Equity [Roll Forward]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock issued

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

Common stock issued (in shares)

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

Common stock reissued for employee/non-employee director stock plans

'

'

'

30

'

'

'

'

'

'

'

'

'

'

'

Common stock reissued for employee/non-employee director stock plans (in shares)

'

'

'

330

'

'

'

'

'

'

'

'

'

'

'

Issuance of conversion option in 2019 Senior Convertible Notes, net of tax

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Employee stock plans

'

'

'

'

0

'

'

'

'

'

'

'

'

'

'

Net loss attributable to United States Steel Corporation

-53

'

'

'

'

-53

-53

'

'

'

'

'

'

'

'

Dividends on common stock

'

'

'

'

'

-29

'

'

'

'

'

'

'

'

'

Changes during year, net of taxes

[1]

-255

'

'

'

'

'

'

-230

-230

'

'

'

'

'

'

Changes during year, equity investee net of taxes

[1]

'

'

'

'

'

'

'

-25

-25

'

'

'

'

'

'

Changes during year

'

'

'

'

'

'

'

'

'

-44

-44

'

'

'

'

Net loss

0

'

'

'

'

'

'

'

'

'

'

'

'

0

0

Other

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

Total comprehensive loss

-352

-352

'

'

'

'

'

'

'

'

'

'

'

'

'

Related income tax (provision) benefit:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Pension and other benefits adjustments

52

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance at end of year at Dec. 31, 2011

'

'

151

-550

3,650

3,616

'

-3,598

'

231

'

-3,367

3,500

1

'

Balance at end of year (in shares) at Dec. 31, 2011

'

'

150,926

-6,922

'

'

'

'

'

'

'

'

'

'

'

Increase (Decrease) in Stockholders' Equity [Roll Forward]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock issued

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

Common stock issued (in shares)

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

Common stock reissued for employee/non-employee director stock plans

'

'

'

29

'

'

'

'

'

'

'

'

'

'

'

Common stock reissued for employee/non-employee director stock plans (in shares)

'

'

'

278

'

'

'

'

'

'

'

'

'

'

'

Issuance of conversion option in 2019 Senior Convertible Notes, net of tax

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Employee stock plans

'

'

'

'

2

'

'

'

'

'

'

'

'

'

'

Net loss attributable to United States Steel Corporation

-124

'

'

'

'

-124

-124

'

'

'

'

'

'

'

'

Dividends on common stock

'

'

'

'

'

-29

'

'

'

'

'

'

'

'

'

Changes during year, net of taxes

[1]

-15

'

'

'

'

'

'

-8

-8

'

'

'

'

'

'

Changes during year, equity investee net of taxes

[1]

'

'

'

'

'

'

'

-7

-7

'

'

'

'

'

'

Changes during year

'

'

'

'

'

'

'

'

'

114

114

'

'

'

'

Net loss

1

'

'

'

'

'

'

'

'

'

'

'

'

-1

-1

Other

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

Total comprehensive loss

-25

-26

'

'

'

'

'

'

'

'

'

'

'

'

'

Related income tax (provision) benefit:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Pension and other benefits adjustments

-74

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance at end of year at Dec. 31, 2012

3,477

'

151

-521

3,652

3,463

'

-3,613

'

345

'

-3,268

3,477

1

'

Balance at end of year (in shares) at Dec. 31, 2012

'

'

150,926

-6,644

'

'

'

'

'

'

'

'

'

'

'

Increase (Decrease) in Stockholders' Equity [Roll Forward]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock issued

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

Common stock issued (in shares)

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

Common stock reissued for employee/non-employee director stock plans

'

'

'

41

'

'

'

'

'

'

'

'

'

'

'

Common stock reissued for employee/non-employee director stock plans (in shares)

'

'

'

398

'

'

'

'

'

'

'

'

'

'

'

Issuance of conversion option in 2019 Senior Convertible Notes, net of tax

31

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Employee stock plans

'

'

'

'

-16

'

'

'

'

'

'

'

'

'

'

Net loss attributable to United States Steel Corporation

-1,672

'

'

'

'

-1,672

-1,672

'

'

'

'

'

'

'

'

Dividends on common stock

'

'

'

'

'

-29

'

'

'

'

'

'

'

'

'

Changes during year, net of taxes

[1]

1,486

'

'

'

'

'

'

1,444

1,444

'

'

'

'

'

'

Changes during year, equity investee net of taxes

[1]

'

'

'

'

'

'

'

42

42

'

'

'

'

'

'

Changes during year

'

'

'

'

'

'

'

'

'

30

30

'

'

'

'

Net loss

0

'

'

'

'

'

'

'

'

'

'

'

'

0

0

Other

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

Total comprehensive loss

-156

-156

'

'

'

'

'

'

'

'

'

'

'

'

'

Related income tax (provision) benefit:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Pension and other benefits adjustments

-762

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance at end of year at Dec. 31, 2013

$3,348

'

$151

($480)

$3,667

$1,762

'

($2,127)

'

$375

'

($1,752)

$3,348

$1

'

Balance at end of year (in shares) at Dec. 31, 2013

'

'

150,926

-6,246

'

'

'

'

'

'

'

'

'

'

'

[1]

Year Ended December 31,(Dollars in millions) 2013 2012 2011Related income tax (provision) benefit: Pension and other benefits adjustments $(762) $(74) $52

Nature_of_Business_and_Signifi

Nature of Business and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Nature of Business and Significant Accounting Policies	'
	Nature of Business and Significant Accounting Policies
	Nature of Business
	United States Steel Corporation (U. S. Steel or the Company) produces and sells steel plant products, including flat-rolled and tubular products, in North America and Europe. Operations in North America also include iron ore and coke production facilities, railroad services and real estate operations.
	Significant Accounting Policies
	Principles applied in consolidation
	These financial statements include the accounts of U. S. Steel and its majority-owned subsidiaries. Additionally, variable interest entities for which U. S. Steel is the primary beneficiary are included in the consolidated financial statements and their impacts are either partially or completely offset by noncontrolling interests. Intercompany accounts, transactions and profits have been eliminated in consolidation.
	Investments in entities over which U. S. Steel has significant influence are accounted for using the equity method of accounting and are carried at U. S. Steel’s share of net assets plus loans, advances and our share of earnings less distributions. Differences in the basis of the investment and the underlying net asset value of the investee, if any, are amortized into earnings over the remaining useful life of the associated assets.
	Income or loss from investees includes U. S. Steel’s share of income or loss from equity method investments, which is generally recorded a month in arrears, except for significant and unusual items which are recorded in the period of occurrence. Gains or losses from changes in ownership of unconsolidated investees are recognized in the period of change. Intercompany profits and losses on transactions with equity investees have been eliminated in consolidation, subject to lower of cost or market inventory adjustments.
	U. S. Steel evaluates impairment of its equity method investments whenever circumstances indicate that a decline in value below carrying value is other than temporary. Under these circumstances, we adjust the investment down to its estimated fair value, which then becomes its new carrying value.
	Investments in companies whose equity has no readily determinable fair value are carried at cost and are periodically reviewed for impairment.
	Use of estimates
	Generally accepted accounting principles require management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at year-end and the reported amounts of revenues and expenses during the year. Significant items subject to such estimates and assumptions include the carrying value of property, plant and equipment; goodwill and intangible assets; valuation allowances for receivables, inventories and deferred income tax assets and liabilities; environmental liabilities; liabilities for potential tax deficiencies; potential litigation claims and settlements; and assets and obligations related to employee benefits. Actual results could differ materially from the estimates and assumptions used.
	Sales recognition
	Sales are recognized when products are shipped, properties are sold or services are provided to customers; the sales price is fixed and determinable; collectability is reasonably assured; and title and risks of ownership have passed to the buyer. Shipping and other transportation costs charged to buyers are recorded in both sales and cost of sales.
	Cash and cash equivalents
	Cash and cash equivalents include cash on deposit and investments in highly liquid debt instruments with maturities of three months or less.
	Inventories
	Inventories are carried at the lower of cost or market. Fixed costs related to abnormal production capacity are expensed in the period incurred rather than capitalized into inventory.
	LIFO (last-in, first-out) is the predominant method of inventory costing for inventories in the United States and FIFO (first-in, first-out) is the predominant method used in Canada and Europe. The LIFO method of inventory costing was used on 59 percent and 56 percent of consolidated inventories at December 31, 2013 and 2012, respectively.
	Derivative instruments
	U. S. Steel uses commodity-based and foreign currency derivative instruments to manage its exposure to price and foreign currency exchange rate risk. Forward physical purchase contracts and foreign exchange forward contracts are used to reduce the effects of fluctuations in the purchase price of natural gas and certain nonferrous metals and also certain business transactions denominated in foreign currencies. U. S. Steel has not elected to designate derivative instruments as qualifying for hedge accounting treatment. As a result, the changes in fair value of these derivatives are recognized immediately in results of operations. See Note 13 for further details on U. S. Steel’s derivatives.
	Goodwill and identifiable intangible assets
	Goodwill represents the excess of the cost over the fair value of acquired identifiable tangible and intangible assets and liabilities assumed from businesses acquired. Goodwill is tested for impairment at the reporting unit level annually in the third quarter and whenever events or circumstances indicate that the carrying value may not be recoverable.
	U. S. Steel evaluates goodwill for impairment by either performing a qualitative evaluation or a two-step quantitative test, which involves comparing the estimated fair value of the associated reporting unit to its carrying value, including goodwill. The qualitative evaluation is an assessment of factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount, including goodwill. Factors considered as part of the qualitative assessment include entity-specific, industry, market and general economic conditions. U. S. Steel may elect to bypass this qualitative assessment for some or all of its reporting units and perform a two step quantitative test. The quantitative test involves estimating a reporting unit's fair value based upon a discounted cash flow model, using a market participant approach. U. S. Steel performed the two step quantitative test during the third quarter of 2013 and recorded an impairment charge of approximately $1.8 billion.
	U. S. Steel has determined that certain acquired intangible assets have indefinite useful lives. These assets are reviewed for impairment annually and whenever events or circumstances indicate that the carrying value may not be recoverable.
	Identifiable intangible assets with finite lives are amortized on a straight-line basis over their estimated useful lives and are reviewed for impairment whenever events or circumstances indicate that the carrying value may not be recoverable.
	See Note 11 for further details on our evaluation of goodwill and intangible asset impairment.
	Property, plant and equipment
	Property, plant and equipment is carried at cost and is depreciated on a straight-line basis over the estimated useful lives of the assets.
	Depletion of mineral properties is based on rates which are expected to amortize cost over the estimated tonnage of minerals to be removed.
	U. S. Steel evaluates impairment of its property, plant and equipment whenever circumstances indicate that the carrying value may not be recoverable. Asset impairments are recognized when the carrying value of an asset grouping exceeds its aggregate projected undiscounted cash flows.
	When property, plant and equipment depreciated on a group basis is sold or otherwise disposed of, proceeds are credited to accumulated depreciation, depletion and amortization with no immediate effect on income. When property, plant and equipment depreciated on an individual basis is sold or otherwise disposed of, any gains or losses are reflected in income. Gains on disposal of long-lived assets are recognized when earned. If a loss on disposal is expected, such losses are recognized when the assets are reclassified as assets held for sale or when impaired as part of an asset group’s impairment. During the third quarter of 2013, the requirement to move to the second step of the annual goodwill impairment analysis was considered a triggering event and U. S. Steel completed a review of its long-lived assets. This review performed during the third quarter of 2013 indicated that the assets were not impaired. There were no triggering events that required fixed assets to be evaluated for impairment in 2012. During the third and fourth quarters of 2011, we evaluated the U. S. Steel Europe (USSE) asset group’s long-lived assets for impairment because the potential disposition of U. S. Steel Serbia (USSS) was considered a triggering event. Although we recorded a loss of $399 million as a result of the sale of USSS in the first quarter of 2012 (this transaction did not meet held-for-sale criteria at December 31, 2011), the fixed asset impairment evaluations did not indicate an impairment at December 31, 2011 since we test the fixed assets at the asset group level, which was USSE at that date. USSE consisted of both U. S. Steel Košice (USSK) and USSS and the estimated fair value of the USSE asset group exceeded its carrying value and resulted in no impairment of fixed assets at the USSE asset group level at December 31, 2011.
	Major maintenance activities
	U. S. Steel incurs maintenance costs on all of its major equipment. Costs that extend the life of the asset, materially add to its value, or adapt the asset to a new or different use are separately capitalized in property, plant and equipment and are depreciated over the estimated useful life. All other repair and maintenance costs are expensed as incurred.
	Environmental remediation
	Environmental expenditures are capitalized if the costs mitigate or prevent future contamination or if the costs improve existing assets’ environmental safety or efficiency. U. S. Steel provides for remediation costs and penalties when the responsibility to remediate is probable and the amount of associated costs is reasonably estimable. The timing of remediation accruals typically coincides with completion of studies defining the scope of work to be undertaken or the commitment to a formal plan of action. Remediation liabilities are accrued based on estimates of believed environmental exposure and are discounted if the amount and timing of the cash disbursements are readily determinable.
	Asset retirement obligations
	Asset retirement obligations (AROs) are initially recorded at fair value and are capitalized as part of the cost of the related long-lived asset and depreciated in accordance with U. S. Steel’s depreciation policies for property, plant and equipment. The fair value of the obligation is determined as the discounted value of expected future cash flows. Accretion expense is recorded each month to increase this discounted obligation over time. Certain AROs related to disposal costs of the majority of assets at our integrated steel facilities are not recorded because they have an indeterminate settlement date. These AROs will be initially recognized in the period in which sufficient information exists to estimate their fair value. See Note 17 for further details on U. S. Steel's AROs.
	Pensions, other postretirement and postemployment benefits
	U. S. Steel has defined contribution or multi-employer arrangements for pension benefits for more than half of its North American employees and non-contributory defined benefit pension plans covering the remaining North American employees. U. S. Steel has defined benefit retiree health care and life insurance plans (Other Benefits) that cover the majority of its employees in North America upon their retirement. Non-union salaried employees in the United States hired on or after July 1, 2003 participate in a defined contribution plan. In addition, most domestic salaried employees participate in defined contribution plans (401(k) plans). The Steelworkers Pension Trust (SPT), a multi-employer pension plan, to which U. S. Steel contributes on the basis of a fixed dollar amount for each hour worked by participating employees, currently covers approximately 60 percent of our union employees in the United States. Government-sponsored programs into which U. S. Steel makes required contributions cover the majority of U. S. Steel’s European employees. In Canada, the majority of employees of USSC participate in defined benefit pension plans and retiree health and life insurance plans. Union employees hired after October 15, 2011 at the Hamilton Plant and after April 16, 2010 at the Lake Erie Plant are covered by defined contribution arrangements. Non-union salaried employees in Canada hired after 1997 participate in defined contribution arrangements.
	The net pension and Other Benefits obligations and the related periodic costs are based on, among other things, assumptions of the discount rate, estimated return on plan assets, salary increases, the mortality of participants and the current level and future escalation of health care costs. Additionally, U. S. Steel recognizes an obligation to provide postemployment benefits for disability-related claims covering indemnity and medical payments for certain employees in North America. The obligation for these claims and the related periodic costs are measured using actuarial techniques and assumptions. Actuarial gains and losses occur when actual experience differs from any of the many assumptions used to value the benefit plans, or when assumptions change. The Company recognizes into income on an annual basis any unrecognized actuarial net gains or losses that exceed 10 percent of the larger of the projected benefit obligation or plan assets (the corridor), amortized over the plan participants' average life expectancy or average future service, depending on the demographics of the plan.
	Concentration of credit and business risks
	U. S. Steel is exposed to credit risk in the event of nonpayment by customers, principally within the automotive, container, construction, steel service center, appliance and electrical, conversion, and oil, gas and petrochemical industries. Changes in these industries may significantly affect U. S. Steel’s financial performance and management’s estimates. U. S. Steel mitigates its exposure to credit risk by performing ongoing credit evaluations and, when deemed necessary, requiring letters of credit, credit insurance, prepayments, guarantees or other collateral.
	The majority of U. S. Steel’s customers are located in North America and Europe. No single customer accounted for more than 10 percent of gross annual revenues.
	Foreign currency translation
	U. S. Steel is subject to the risk of the effects of exchange rates on revenues and operating costs and existing assets or liabilities denominated in currencies other than our reporting currency, the U.S. dollar.
	The functional currency for U. S. Steel Europe (USSE) is the euro (€). U. S. Steel Canada Inc.’s (USSC) functional currency is the Canadian dollar (C$). Assets and liabilities of these entities are translated into U.S. dollars at period-end exchange rates. Revenue and expenses are translated using the average exchange rate for the reporting period. Resulting translation adjustments are recorded in the accumulated other comprehensive income (loss) component of stockholders’ equity. Gains and losses from foreign currency transactions are included in net income (loss) for the period.
	Stock-based compensation
	U. S. Steel accounts for its various stock-based employee compensation plans in accordance with the guidance in Accounting Standards Codification (ASC) Topic 718 on stock compensation (see Note 12).
	Deferred taxes
	Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. The realization of deferred tax assets is assessed quarterly based on several interrelated factors. These factors include U. S. Steel’s expectation to generate sufficient future taxable income and the projected time period over which these deferred tax assets will be realized. U. S. Steel records a valuation allowance when necessary to reduce deferred tax assets to the amount that will more likely than not be realized. Deferred tax liabilities have not been recognized for the undistributed earnings of certain foreign subsidiaries because management intends to indefinitely reinvest such earnings in foreign operations. See Note 8 for further details of deferred taxes.
	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 automobile 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.
	Sales taxes
	Sales are recorded net of sales taxes charged to customers. Sales taxes primarily relate to value-added tax on sales.
	Reclassifications and out of period adjustments
	Certain reclassifications of prior years’ data have been made to conform to the current year presentation.
	In 2013, the Company revised its classification of certain deferred tax assets as of December 31, 2012. The revision resulted in a $122 million increase to current deferred tax assets with a corresponding decrease to non-current deferred tax assets. The revision, which the Company determined is not material to its consolidated financial position, had no impact on the Consolidated Statement of Operations, Statement of Comprehensive Income/(Loss) or Statement of Cash Flows.
	In 2013, the Company recorded two out of period adjustments to correct the presentation of deferred taxes. The adjustments recorded were a tax benefit of approximately $13 million and a tax charge of approximately $19 million for deferred taxes related to fixed assets for prior years' differences between the financial statement carrying amounts of assets and liabilities and their tax basis for U.S. federal and state income tax purposes. Management has determined the impact of these out of period adjustments was not material to any prior period or the year ended December 31, 2013 and as a result, recorded the adjustments in the 2013 results.
	In 2011, the Company recorded an out of period adjustment related to its enterprise resource planning project to recorded fixed assets with a corresponding increase to net income of approximately $10 million. Management has determined that the impact of the out of period adjustment was not material to any prior period or the year ended December 31, 2011, and as a result, recorded the adjustment in the 2011 results.

New_Accounting_Standards

New Accounting Standards	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
New Accounting Standards	'
	New Accounting Standards
	On February 5, 2013, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income (ASU 2013-02). ASU 2013-02 requires companies to present information about reclassification adjustments from accumulated other comprehensive income, including the amount of the reclassification and the income statement line items affected by the reclassification. The information must be presented in the financial statements in a single note or on the face of the financial statements. ASU 2013-02 is effective for interim and annual periods beginning after December 15, 2012. U. S. Steel adopted ASU 2013-02 effective January 1, 2013 and has provided the required disclosures in Note 19.
	On July 18, 2013, the FASB issued Accounting Standards Update No. 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (ASU 2013-11). ASU 2013-11 requires the netting of unrecognized tax benefits (UTBs) against a deferred tax asset for a loss or other carryforward that would apply in settlement of the uncertain tax positions. UTBs are required to be netted against all available same-jurisdiction loss or other tax carryforwards that would be utilized, rather than only against carryforwards that are created by the UTBs. ASU 2013-11 is effective for interim and annual periods beginning after December 15, 2013. U. S. Steel early adopted ASU 2013-11 in the second quarter of 2013 on a prospective basis. The adoption did not have a significant impact on U. S. Steel's financial statements.
	On July 27, 2012 the FASB issued Accounting Standards Update No. 2012-02, Testing Indefinite-Lived Intangible Assets for Impairment (ASU 2012-02). ASU 2012-02 is intended to reduce the cost and complexity of testing indefinite-lived intangible assets other than goodwill for impairment. It allows companies to perform a qualitative assessment to determine whether further impairment testing of indefinite-lived intangible assets is necessary, similar in approach to the goodwill impairment assessment noted below. ASU 2012-02 was effective for annual and interim impairment tests performed for fiscal years beginning after September 15, 2012; however, early adoption was permitted. U. S. Steel early adopted ASU 2012-02 and performed the qualitative assessment of its indefinite-lived water rights during the third quarter of 2012.
	On September 15, 2011, the FASB issued Accounting Standards Update No. 2011-08, Testing Goodwill for Impairment (ASU 2011-08), which amends the guidance in ASC 350-20. The amendments in ASU 2011-08 provide entities with the option of performing a qualitative assessment before performing the first step of a two-step impairment test. If entities determine, on the basis of qualitative factors, it is not more likely than not that the fair value of the reporting unit is less than the carrying amount, then performing a two-step impairment test would be unnecessary. However, if an entity concludes otherwise, then it is required to perform the first step of the two-step impairment test by calculating the fair value of the reporting unit and comparing the fair value with the carrying amount of the reporting unit. If the carrying amount of a reporting unit exceeds its fair value, then the entity is required to perform the second step of the goodwill impairment test to measure the amount of the impairment loss, if any. ASU 2011-08 also provides entities with the option to bypass the qualitative assessment for any reporting unit in any period and proceed directly to the first step of the two-step impairment test. ASU 2011-08 was effective for interim and annual periods beginning after December 15, 2011. U. S. Steel adopted ASU 2011-08 on January 1, 2012.
	On June 16, 2011, the FASB issued Accounting Standards Update No. 2011-05, Comprehensive Income (Topic 220): Presentation of Comprehensive Income (ASU 2011-05). The amendments in ASU 2011-05 require entities to present the total of comprehensive income, the components of net income, and the components of other comprehensive income either in a single continuous statement of comprehensive income or in two separate but consecutive statements. Additionally, the amendments in ASU 2011-05 require an entity to present on the face of the financial statements reclassification adjustments for items that are reclassified from other comprehensive income to net income in the statement(s) where the components of net income and the components of other comprehensive income are presented. ASU 2011-05 was effective for interim and annual periods beginning after December 15, 2011. On December 23, 2011, the FASB issued Accounting Standards Update No. 2011-12, Comprehensive Income (Topic 220): Deferral of the Effective Date for Amendments to the Presentation of Reclassifications of Items Out of Accumulated Other Comprehensive Income in Accounting Standards Update No. 2011-05 (ASU 2011-12) to defer the new requirement to present components of reclassifications of other comprehensive income on the face of the financial statements. Companies were still required to adopt the other requirements contained in ASU 2011-05. U. S. Steel adopted ASU 2011-05 and has provided the required disclosures in a separate statement immediately following the Consolidated Statement of Operations.
	On May 12, 2011, the FASB issued Accounting Standards Update No. 2011-04, Fair Value Measurement (Topic 820): Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRSs (ASU 2011-04). The amendments in ASU 2011-04 change the wording used to describe many of the requirements in accounting standards generally accepted in the United States (U.S. GAAP) for measuring fair value and for disclosing information about fair value measurements. The amendments are intended to create comparability of fair value measurements presented and disclosed in financial statements prepared in accordance with U.S. GAAP and International Financial Reporting Standards. ASU 2011-04 was effective for interim and annual periods beginning after December 15, 2011. The adoption of this ASU did not have a significant impact on U. S. Steel’s financial statements.

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Segment Information	'
	Segment Information
	U. S. Steel has three reportable segments: Flat-rolled Products (Flat-rolled), USSE and Tubular Products (Tubular). The results of several operating segments that do not constitute reportable segments are combined and disclosed in the Other Businesses category.
	The Flat-rolled segment includes the operating results of U. S. Steel’s North American integrated steel plants and equity investees involved in the production of slabs, rounds, strip mill plates, sheets, tin mill products as well as all iron ore and coke production facilities in the United States and Canada. These operations primarily serve North American customers in the service center, conversion, transportation (including automotive), construction, container, appliance and electrical markets. Flat-rolled supplies steel rounds and hot-rolled bands to Tubular.
	The USSE segment includes the operating results of USSK, U. S. Steel’s integrated steel plant and coke production facilities in Slovakia. Prior to January 31, 2012, the USSE segment also included the operating results of U. S. Steel Serbia (USSS), U. S. Steel’s integrated steel facility and other facilities in Serbia, and an equity investee, which were sold on January 31, 2012 (see Note 4). USSE primarily serves customers in the European construction, service center, conversion, container, transportation (including automotive), appliance and electrical, and oil, gas and petrochemical markets. USSE produces and sells slabs, sheet, strip mill plate, tin mill products and spiral welded pipe, as well as heating radiators and refractory ceramic materials.
	The Tubular segment includes the operating results of U. S. Steel’s tubular production facilities, primarily in the United States, and equity investees in the United States and Brazil. These operations produce and sell seamless and electric resistance welded (ERW) steel casing and tubing (commonly known as oil country tubular goods or OCTG), standard and line pipe and mechanical tubing and primarily serve customers in the oil, gas and petrochemical markets.
	Other Businesses includes railroad services and real estate operations.
	The chief operating decision maker evaluates performance and determines resource allocations based on a number of factors, the primary measure being income (loss) from operations. Income (loss) from operations for reportable segments and Other Businesses does not include net interest and other financial costs, income taxes, postretirement benefit expenses (other than service cost and amortization of prior service cost for active employees) and certain other items that management believes are not indicative of future results. Information on segment assets is not disclosed, as it is not reviewed by the chief operating decision maker.
	The accounting principles applied at the operating segment level in determining income from operations are generally the same as those applied at the consolidated financial statement level. The transfer value for steel rounds from Flat-rolled to Tubular is based on cost. All other intersegment sales and transfers are accounted for at market-based prices and are eliminated at the corporate consolidation level. Corporate selling, general and administrative expenses and costs related to certain former businesses are allocated to the reportable segments and Other Businesses based on measures of activity that management believes are reasonable.
	The results of segment operations are as follows:
	(In millions)		Customer				Intersegment				Net			Income			Income			Depreciation,		Capital
			Sales				Sales				Sales			(loss)			(loss)			depletion &		expenditures
														from			from			amortization
														investees			operations
	2013
	Flat-rolled		$	11,572			$	1,258			$	12,830		$	69		$	105		$	512	$	349
	USSE		2,941				3				2,944			—			28			95		40
	Tubular		2,772				5				2,777			(25		)	190			62		69
	Total reportable segments		17,285				1,266				18,551			44			323			669		458
	Other Businesses		139				134				273			(4		)	77			15		19
	Reconciling Items and Eliminations		—				(1,400		)		(1,400		)	—			(2,300		)	—		—
	Total		$	17,424			$	—			$	17,424		$	40		$	(1,900	)	$	684	$	477
	2012
	Flat-rolled		$	12,908			$	1,647			$	14,555		$	152		$	400		$	491	$	625
	USSE		2,949				145				3,094			—			34			102		38
	Tubular		3,283				8				3,291			(6		)	366			58		42
	Total reportable segments		19,140				1,800				20,940			146			800			651		705
	Other Businesses		188				139				327			(2		)	55			10		18
	Reconciling Items and Eliminations		—				(1,939		)		(1,939		)	—			(608		)	—		—
	Total		$	19,328			$	—			$	19,328		$	144		$	247		$	661	$	723
	2011
	Flat-rolled		$	12,367			$	1,360			$	13,727		$	98		$	469		$	485	$	616
	USSE		4,306				69				4,375			1			(162		)	140		109
	Tubular		3,034				7				3,041			(14		)	316			44		104
	Total reportable segments		19,707				1,436				21,143			85			623			669		829
	Other Businesses		177				345				522			—			46			12		19
	Reconciling Items and Eliminations		—				(1,781		)		(1,781		)	—			(404		)	—		—
	Total		$	19,884			$	—			$	19,884		$	85		$	265		$	681	$	848
	The following is a schedule of reconciling items to income (loss) from operations:
	(In millions)		2013				2012				2011
	Items not allocated to segments:
	Postretirement benefit expense(a)		$	(221	)		$	(297	)		$	(386	)
	Other items not allocated to segments:
	Impairment of goodwill (Note11)		(1,806		)		$	—			$	—
	Restructuring and other charges (Note 23)		(248		)		—				—
	Environmental remediation charge		(32		)		—				(18		)
	Write-off of equity investment (Note 9)		(16		)		—				—
	Supplier contract dispute settlement		23				15				—
	Net loss on the sale of assets (Note 4)		—				(310		)		—
	Labor agreement lump sum payments (Note 15)		—				(35		)		—
	Property tax settlements		—				19				—
	Total other items not allocated to segments		(2,079		)		(311		)		(18		)
	Total reconciling items		$	(2,300	)		$	(608	)		$	(404	)
	(a)	Consists of the net periodic benefit cost elements, other than service cost and amortization of prior service cost for active employees, associated with our pension, retiree health care and life insurance benefit plans.
	Net Sales by Product:
	The following summarizes net sales by product:
	(In millions)		2013				2012				2011
	Flat-rolled		$	13,508			$	14,721			$	15,861
	Tubular		2,826				3,246				2,986
	Other(a)		1,090				1,361				1,037
	Total		$	17,424			$	19,328			$	19,884
	(a)	Primarily includes sales of steel production by-products, railroad services and real estate operations.
	Geographic Area:
	The information below summarizes net sales, property, plant and equipment and equity method investments based on the location of the operating segment to which they relate.
(In millions)		Year		Net				Assets
				Sales
North America		2013		$	14,484			$	5,425		(a)
		2012		$	16,379			$	5,907		(a)
		2011		$	15,578			$	5,869		(a)
Europe		2013		2,940				1,022			(b)
		2012		2,949				1,034			(b)
		2011		4,306				1,321			(b)
Other Foreign Countries		2013		—				33
		2012		—				37
		2011		—				40
Total		2013		$	17,424			$	6,480
		2012		$	19,328			$	6,978
		2011		$	19,884			$	7,230
(a)	Assets with a book value of $4,443 million, $4,523 million and $4,424 million were located in the United States at December 31, 2013, 2012 and 2011, respectively.
(b)	Assets with a book value of $1,022 million, $1,034 million and $1,064 million were located in Slovakia at December 31, 2013, 2012 and 2011, respectively.

Dispositions_and_Assets_Held_f

Dispositions and Assets Held for Sale	12 Months Ended
	Dec. 31, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Dispositions and Assets Held for Sale	'
	Dispositions and Assets Held for Sale
	Birmingham Southern Railroad Company
	On February 1, 2012, U. S. Steel completed the sale of the majority of operating assets of Birmingham Southern Railroad Company and the Port Birmingham Terminal. As a result of the transaction, U. S. Steel recognized a pretax gain of $89 million.
	U. S. Steel Serbia
	On January 31, 2012, U. S. Steel sold USSS to the Republic of Serbia for a purchase price of one dollar. In addition, USSK received $40 million for certain intercompany balances owed by USSS for raw materials and support services. As a result of this transaction, U. S. Steel recorded a non-cash pretax charge of $399 million.

Net_Interest_and_Other_Financi

Net Interest and Other Financial Costs	12 Months Ended
	Dec. 31, 2013
Other Income and Expenses [Abstract]	'
Net Interest and Other Financial Costs	'
	Net Interest and Other Financial Costs
	(In millions)		2013			2012			2011
	Interest income:
	Interest income		$	(3	)	$	(7	)	$	(6	)
	Interest expense and other financial costs:
	Interest incurred(a)		285			255			229
	Less interest capitalized		19			41			39
	Total interest expense		266			214			190
	Foreign currency net loss (b)		11			7			27
	Financial costs on:
	Sale of receivables		3			4			4
	Amended Credit Agreement		4			4			5
	USSK credit facilities		3			3			2
	Other (c)		28			—			—
	Amortization of discounts and deferred financing costs		20			16			16
	Total other financial costs		69			34			54
	Net interest and other financial costs		$	332		$	241		$	238
	(a)	Includes a pretax charge of $34 million during 2013 related to premiums on the repurchase of $542 million of our 4.00% Senior Convertible Notes.
	(b)	The functional currency for USSE is the euro and the functional currency for USSC is the Canadian dollar. Foreign currency net loss is a result of transactions denominated in currencies other than the euro or Canadian dollar. Additionally, foreign currency net loss includes the impacts of the remeasurement of a U.S. dollar-denominated intercompany loan to a European subsidiary and the impacts of euro-U.S. dollar derivatives activity. Effective January 1, 2012, the functional currency of the European entity was changed from the euro to the U.S. dollar because of significant changes in economic facts and circumstances, including the sale of U. S. Steel Serbia. The change in functional currency has been applied on a prospective basis since January 1, 2012.
	(c)	Consists primarily of a charge of $22 million in 2013 related to a guarantee of an unconsolidated equity investment for which payment by U. S. Steel is probable (see Note 24).

Income_and_Dividends_Per_Commo

Income and Dividends Per Common Share	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Income and Dividends Per Common Share	'
	Income and Dividends Per Common Share
	Net Loss per Share Attributable to United States Steel Corporation Shareholders
	Basic net loss per common share is based on the weighted average number of common shares outstanding during the period.
	Diluted earnings per common share assumes the exercise of stock options, the vesting of restricted stock units and performance awards and the conversion of convertible notes, provided in each case the effect is dilutive. The “if-converted” method is used to calculate the dilutive effect of the Senior Convertible Notes due in 2014 and the “treasury stock” method is used to calculate the dilutive effect of the Senior Convertible Notes due in 2019 (due to our current intent and policy, among other factors, to settle the principal amount of the 2019 Senior Convertible Notes in cash upon conversion).
	(Dollars in millions, except per share amounts)	2013				2012			2011
	Net loss attributable to United States Steel Corporation shareholders	$	(1,672	)		$	(124	)	$	(53	)
	Plus income effect of assumed conversion-interest on convertible notes	—				—			—
	Net loss after assumed conversion	$	(1,672	)		$	(124	)	$	(53	)
	Weighted-average shares outstanding (in thousands):
	Basic	144,578				144,237			143,967
	Effect of convertible notes	—				—			—
	Effect of stock options, restricted stock units and performance awards	—				—			—
	Adjusted weighted-average shares outstanding, diluted	144,578				144,237			143,967
	Basic loss per common share	$	(11.56	)		(0.86		)	(0.37		)
	Diluted loss per common share	$	(11.56	)		(0.86		)	(0.37		)
	The following table summarizes the securities that were antidilutive, and therefore, were not included in the computation of diluted loss per common share:
	(In thousands)	2013			2012			2011
	Securities granted under the 2005 Stock Incentive Plan	7,039			5,581			3,912
	Securities convertible under the Senior Convertible Notes	14,017		(a)	27,059			27,059
	Total	21,056			32,640			30,971
	(a) On March 27, 2013, we repurchased approximately $542 million aggregate principal amount of our 4% Senior Convertible Notes due in 2014. If the repurchases had occurred on January 1, 2013, the antidilutive securities would have been 10,058 thousand for the year ended December 31, 2013.
	Dividends Paid per Share
	Quarterly dividends on common stock were five cents per share for each quarter in 2013, 2012 and 2011.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2013
Inventory Disclosure [Abstract]	'
Inventories	'
	Inventories
	(In millions)	December 31, 2013		December 31, 2012
	Raw materials	$	1,011	$	945
	Semi-finished products	1,023		883
	Finished products	558		573
	Supplies and sundry items	96		102
	Total	$	2,688	$	2,503
	Current acquisition costs were estimated to exceed the above inventory values at December 31 by $1.0 billion in both 2013 and 2012. Cost of sales increased and income from operations decreased by $9 million during 2013 as a result of liquidations of LIFO inventories. Cost of sales decreased and income from operations was improved by $27 million and $3 million in 2012 and 2011, respectively, as a result of liquidations of LIFO inventories.
	During the years ended December 31, 2012 and 2011, we recorded lower of cost or market related charges totaling approximately $35 million and $85 million, respectively.
	Inventory includes $81 million and $86 million of land held for residential/commercial development as of December 31, 2013 and 2012, respectively.
	From time to time, U. S. Steel enters into coke swap agreements designed to reduce transportation costs. U. S. Steel shipped and received approximately 1,025,000 tons and 900,000 tons of coke under swap agreements during 2013 and 2012, respectively.
	U. S. Steel also has entered into iron ore pellet swap agreements. U. S. Steel shipped and received approximately 3,145,000 tons and 2,855,000 tons of iron ore pellets during 2013 and 2012, respectively.
	The coke and iron ore pellet swaps are recorded at cost as nonmonetary transactions. There was no income statement impact related to these swaps.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Provisions (benefits) for income taxes
		2013									2012								2011
	(In millions)	Current			Deferred			Total			Current		Deferred			Total			Current			Deferred			Total
	Federal	$	(210	)	$	(167	)	$	(377	)	$	48	$	61		$	109		$	148		$	(92	)	$	56
	State and local	8			(50		)	(42		)	5		23			28			(2		)	15			13
	Foreign	1			(142		)	(141		)	4		(10		)	(6		)	2			9			11
	Total	$	(201	)	$	(359	)	$	(560	)	$	57	$	74		$	131		$	148		$	(68	)	$	80
	A reconciliation of the federal statutory tax rate of 35 percent to total provisions follows:
	(In millions)	2013			2012			2011
	Statutory rate applied to income (loss) before income taxes	$	(781	)	$	2		$	9
	Effects of foreign operations	467			266			184
	Worthless stock loss and bad debt deduction	(417		)	—			—
	Goodwill impairment	410			—			—
	Tax accounting benefit related to increase in OCI	(142		)	—			—
	Excess percentage depletion	(94		)	(107		)	(102		)
	State and local income taxes after federal income tax effects	(27		)	18			8
	Adjustments of prior years’ federal income taxes	9			(46		)	(11		)
	Tax credits	(3		)	—			(3		)
	Deduction for domestic production activities	12			(7		)	(8		)
	Medicare Part D drug program subsidies	—			(1		)	(6		)
	Other	6			6			9
	Total (benefit) provision	$	(560	)	$	131		$	80
	The tax benefit differs from the domestic statutory rate of 35 percent because of the items listed above, and in particular because it does not reflect any tax benefit for pretax losses in Canada and Serbia (USSS was sold on January 31, 2012), which are jurisdictions where we have, or had, recorded full valuation allowances on deferred tax assets, and also does not reflect any tax provision or benefit for certain foreign currency remeasurement gains and losses that are not recognized in any tax jurisdiction. The tax benefit also differs from the domestic statutory rate of 35 percent due to tax accounting impacts related to items reported in other comprehensive income.
	U. S. Steel will make an election effective December 31, 2013 to liquidate for U.S. income tax purposes a foreign subsidiary that holds most of our international operations. The election will allow us to take a worthless stock loss and bad debt deduction in our 2013 U.S. income tax return for the excess of our investment in the subsidiary over the value of its assets. As a result, the Company recorded a tax benefit of $392 million in the fourth quarter, which includes a $22 million tax benefit that offsets taxes in the same amount charged against other comprehensive income for current year translation adjustments involving USSK. The tax benefit includes a $66 million reduction in U.S. income taxes payable for 2013, as well as a refund of $176 million expected in 2014 from the carryback of 2013 losses to prior years. The remaining $150 million benefit is expected to offset U.S. income taxes in future years. The election to liquidate the foreign subsidiary for U.S. income tax purposes will result in USSK’s income being subject to U.S. income taxes, less any applicable credit for Slovak income taxes paid, effective December 31, 2013.
	For 2013, there was essentially no tax benefit recorded on the $1.8 billion goodwill impairment charge. Included in the 2013 tax benefit is a favorable catch-up adjustment in the fourth quarter of $33 million primarily related to a decrease in forecasted income as well as a discrete tax benefit of $13 million to adjust state deferred taxes. In addition, the 2013 adjustment of prior years' federal income taxes included a charge of approximately $19 million recorded in the fourth quarter to adjust deferred taxes for prior years' differences between the financial statement carrying amounts of assets and liabilities and their tax bases for U.S. federal income tax purposes. For 2012, no significant tax benefit was recorded on the $399 million loss on the sale of USSS. Also included in the 2012 income tax provision is a tax benefit of $20 million relating to adjustments to tax reserves related to the conclusion of certain audits as well as a tax benefit of $26 million to adjust our estimated 2011 federal tax liability to our actual tax liability reflected in our tax return as filed.
	Income tax receivable
	The income tax receivable of $185 million at December 31, 2013 primarily reflects the federal income tax refund of $176 million that we expect to receive in 2014 as a result of carrying back our 2013 net operating loss to prior years.
	Unrecognized tax benefits
	Unrecognized tax benefits are the differences between a tax position taken, or expected to be taken, in a tax return and the benefit recognized for accounting purposes pursuant to the guidance in ASC Topic 740 on income taxes. The total amount of unrecognized tax benefits was $127 million, $85 million and $110 million as of December 31, 2013, 2012 and 2011, respectively.
	The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate was $69 million as of December 31, 2013.
	U. S. Steel records interest related to uncertain tax positions as a part of net interest and other financial costs in the Statement of Operations. Any penalties are recognized as part of selling, general and administrative expenses. As of December 31, 2013, 2012 and 2011, U. S. Steel had accrued liabilities of $7 million, $7 million and $6 million, respectively, for interest related to unrecognized tax benefits. U. S. Steel currently does not have a liability for tax penalties.
	A tabular reconciliation of unrecognized tax benefits follows:
	(In millions)	2013			2012			2011
	Unrecognized tax benefits, beginning of year	$	85		$	110		$	115
	Increases – tax positions taken in prior years	1			3			1
	Decreases – tax positions taken in prior years	(6		)	(25		)	(4		)
	Increases – current tax positions	70			2			3
	Settlements	—			(5		)	—
	Lapse of statute of limitations	(23		)	—			(5		)
	Unrecognized tax benefits, end of year	$	127		$	85		$	110
	It is reasonably expected that during the next 12 months unrecognized tax benefits related to income tax issues will decrease by approximately $9 million.
	Tax years subject to examination
	Below is a summary of the tax years open to examination by major tax jurisdiction:
	U.S. Federal – 2008 and forward*
	U.S. States – 2007 and forward
	Slovakia – 2003 and forward
	Canada Federal and Provincial – 2009 and forward
	*U. S. Steel’s 2008 and 2009 federal tax years remain open to the extent of net operating losses carried back from 2010.
	Status of Internal Revenue Service (IRS) examinations
	The IRS audit of U. S. Steel’s 2010 and 2011 tax returns began in 2012 and is ongoing. The IRS audit of the 2008 and 2009 tax returns was completed and agreed to in 2012.
	Taxes on foreign income
	Pretax loss and income for 2013, 2012 and 2011 includes domestic (loss)/income of $(899) million, $782 million and $519 million, respectively and losses attributable to foreign sources of $(1,333) million, $(776) million and $(492) million, respectively. Undistributed earnings and profits for U.S. federal income tax purposes of certain consolidated foreign subsidiaries, which includes intercompany interest, amounted to approximately $830 million at December 31, 2013 compared to $2.7 billion at the end of 2012. If such tax earnings and profits were not indefinitely reinvested, a U.S. deferred tax liability of approximately $280 million would have been required. The decrease in tax earnings and profits is mainly attributable to an election effective December 31, 2013 to liquidate for U.S. income tax purposes a foreign subsidiary that holds most of our international operations.
	Deferred taxes
	Deferred tax assets and liabilities resulted from the following:
		December 31,
	(In millions)	2013			2012
	Deferred tax assets:
	Federal tax loss carryforwards (expiring in 2033)	$	386		$	—
	State tax credit carryforwards (expiring in 2027)	7			2
	State tax loss carryforwards (expiring in 2015 through 2033)	37			35
	Minimum tax credit carryforwards	108			157
	General business credit carryforwards	69			66
Foreign tax loss and credit carryforwards (expiring in 2014 through 2033)	713			637
Employee benefits	908			1,704
Receivables, payables and debt	88			89
Expected federal benefit for deducting state deferred income taxes	32			51
Inventory	107			—
Contingencies and accrued liabilities	119			133
Valuation allowances:
Foreign	(1,028		)	(1,099		)
Total deferred tax assets	1,546			1,775
Deferred tax liabilities:
Property, plant and equipment	1,205			1,041
Investments in subsidiaries and equity investees	50			97
Inventory	—			1
Future reduction of foreign tax credits	49			—
Other temporary differences	95			41
Total deferred tax liabilities	1,399			1,180
Net deferred tax asset	$	147		$	595
At December 31, 2013 and 2012, the net domestic deferred tax asset was $88 million and $538 million, respectively. A substantial amount of U. S. Steel’s domestic deferred tax assets relate to employee benefits that will become deductible for tax purposes over an extended period of time as cash contributions are made to employee benefit plans and retiree benefits are paid in the future. We continue to believe it is more likely than not that the net domestic deferred tax asset will be realized.
At December 31, 2013 and 2012, the net foreign deferred tax asset was $59 million and $57 million, respectively, net of established valuation allowances of $1,028 million and $1,099 million, respectively. The net foreign deferred tax asset will fluctuate as the value of the U.S. dollar changes with respect to the euro and the Canadian dollar. At December 31, 2013 and 2012, a full valuation allowance was recorded for the net Canadian deferred tax asset primarily due to cumulative losses in Canada.
If evidence changes and it becomes more likely than not that the Company will realize the net Canadian deferred tax asset, the valuation allowance would be partially or fully reversed. Any reversal of this amount would result in a decrease to income tax expense. The Slovak income tax rate will decrease from 23% to 22% starting in 2014. This change had an insignificant impact on deferred taxes at the end of 2013.

Investments_and_LongTerm_Recei

Investments and Long-Term Receivables	12 Months Ended
	Dec. 31, 2013
Equity Method Investments and Joint Ventures [Abstract]	'
Investments and Long-Term Receivables	'
	Investments and Long-Term Receivables
			December 31,
	(In millions)		2013		2012
	Equity method investments		$	558	$	570
	Receivables due after one year, less allowance of $3 for both periods		58		34
	Other		5		5
	Total		$	621	$	609
	Summarized financial information of all investees accounted for by the equity method of accounting is as follows (amounts represent 100% of investee financial information):
	(In millions)		2013		2012		2011
	Income data – year ended December 31:
	Net Sales		$	3,735	$	4,019	$	3,514
	Operating income		449		650		319
	Net income		413		602		264
	Balance sheet date – December 31:
	Current Assets		$	912	$	1,028
	Noncurrent Assets		1,876		1,981
	Current liabilities		677		569
	Noncurrent Liabilities		852		1,220
	U. S. Steel's portion of the equity in net income for its equity investments as reported in the income from investees line on the Consolidated Statement of Operations was $40 million, $144 million and $85 million for the years ended December 31, 2013, 2012 and 2011, respectively.
	Investees accounted for using the equity method include:
	Investee	Country	December 31, 2013
			Interest
	Acero Prime, S. R. L. de CV	Mexico	40	%
	Apolo Tubulars S.A.	Brazil	50	%
	Baycoat Limited Partnership	Canada	50	%
	Baycoat Limited	Canada	50	%
	Chrome Deposit Corporation	United States	50	%
	Daniel Ross Bridge, LLC	United States	50	%
	D.C. Chrome Limited	Canada	50	%
	Double Eagle Steel Coating Company	United States	50	%
	Double G Coatings Company L.P.	United States	50	%
	Feralloy Processing Company	United States	49	%
	Hibbing Development Company	United States	24.1	%
	Hibbing Taconite Company(a)	United States	14.7	%
	Leeds Retail Center, LLC	United States	38	%
	Patriot Premium Threading Services	United States	50	%
	PRO-TEC Coating Company	United States	50	%
	Strategic Investment Fund Partners I(b)	United States	8.6	%
	Strategic Investment Fund Partners II(b)	United States	4.9	%
	Swan Point Development Company, Inc.	United States	50	%
	Tilden Mining Company, L.C.(a)	United States	15	%
	United Spiral Pipe, LLC	United States	35	%
	USS-POSCO Industries	United States	50	%
	Worthington Specialty Processing	United States	49	%
	(a)	Hibbing Taconite Company (HTC) is an unincorporated joint venture that is owned, in part, by Hibbing Development Company (HDC), which is accounted for using the equity method. Through HDC we are able to influence the activities of HTC, and as such, its activities are accounted for using the equity method.
	Tilden Mining Company, L.C. is a limited liability company and in accordance with ASC Topic 323 “Partnerships and Unincorporated Joint Ventures,” (ASC Topic 323) its financial activities are accounted for using the equity method.
	(b)	Strategic Investment Fund Partners I and II are limited partnerships and in accordance with ASC Topic 323, the financial activities are accounted for using the equity method.
	Dividends and partnership distributions received from equity investees were $13 million in 2013, $98 million in 2012 and $31 million in 2011.
	During 2013, U. S. Steel recognized a non-cash charge of $16 million to write its investment in United Spiral Pipe, LLC (USP) down to zero. Additionally, we recorded a $6 million non-cash charge to write-off an interest receivable due from USP.
	We supply substrate to certain of our equity method investees and from time to time will extend the payment terms for their trade receivables. For discussion of transactions and related receivable and payable balances between U. S. Steel and its investees, see Note 21.

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
	Property, Plant and Equipment
			December 31,
	(In millions)	Useful Lives	2013		2012
	Land and depletable property	—	$	251	$	264
	Buildings	35 years	1,367		1,394
	Machinery and equipment	4-22 years	14,386		14,408
	Information technology	5-6 years	758		709
	Assets under capital lease	2-25 years	37		131
	Total		16,799		16,906
	Less accumulated depreciation and depletion		10,877		10,498
	Net		$	5,922	$	6,408
	Amounts in accumulated depreciation and depletion for assets acquired under capital leases (including sale-leasebacks accounted for as financings) were $5 million and $95 million at December 31, 2013 and 2012, respectively.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Intangible Assets	'
	Goodwill and Intangible Assets
	The changes in the carrying amount of goodwill by segment for the years ended December 31, 2013 and December 31, 2012 are as follows:
		Flat-rolled				USSE				Tubular				Total
		Segment				Segment				Segment
	Balance at January 1, 2012	$	945			$	4			$	834			$	1,783
	Currency translation	39				—				—				39
	Balance at December 31, 2012	$	984			$	4			$	834			$	1,822
	Goodwill from acquisitions	—				—				3				3
	Impairment	(969		)		—				(837		)		(1,806		)
	Currency translation	(15		)		—				—				(15		)
	Balance at December 31, 2013	$	—			$	4			$	—			$	4
	Goodwill represents the excess of the cost over the fair value of acquired identifiable tangible and intangible assets and liabilities assumed from businesses acquired.
	Goodwill is tested for impairment at the reporting unit level annually in the third quarter and whenever events or circumstances indicate the carrying value may not be recoverable. The evaluation of goodwill impairment involves using either a qualitative or quantitative approach as outlined in ASC Topic 350. U. S. Steel completed its annual goodwill impairment evaluation using the two-step quantitative analysis during the third quarter of 2013. We had two reporting units that included nearly all of our goodwill: our Flat-rolled reporting unit and our Texas Operations reporting unit, which is part of our Tubular operating segment.
	In the first step of the analysis, U. S. Steel compared the estimated fair value of each reporting unit to its carrying value, including goodwill. The fair value of the reporting units was determined based on a weighting of income and market approaches. Since the carrying value of both the Flat-rolled and Texas Operations reporting units exceeded the fair value, U. S. Steel performed the second step of the impairment analysis in order to determine the implied fair value of the reporting units’ goodwill. The implied fair value of goodwill represents the excess of fair value of the reporting unit over the fair value amounts assigned to all of the assets and liabilities of the reporting unit as if it were to be acquired in a business combination and the current fair value of the reporting unit (as calculated in the first step) was the purchase price. Any amount remaining after this allocation represents the implied fair value of goodwill. The implied fair value of the respective reporting units’ goodwill was then compared to the carrying value of the goodwill and any excess of carrying value over the implied fair value represents the non-cash impairment charge. The results of the second step analysis showed that the implied fair value of goodwill was zero for both reporting units. Therefore, in 2013, U. S. Steel recorded a goodwill impairment charge of $969 million and $837 million for the Flat-rolled and Texas Operations reporting units, respectively. As a result of the goodwill impairment charge, there is no goodwill remaining within the Flat-rolled and Tubular segments, and goodwill remaining on our consolidated balance sheet at December 31, 2013 is $4 million.
	The impairment of the Flat-rolled reporting unit’s goodwill was primarily driven by the valuation effects of the protracted economic recovery and excess global steelmaking capacity. The impairment of the Texas Operations reporting unit’s goodwill was primarily driven by the adverse price and volume effects of an increased supply of welded tubular products in the U.S. market from the continued high level of tubular product imports and announced additional domestic tubular manufacturing capacity. Due to these factors, U. S. Steel decreased the long term estimates of its operating results and cash flows utilized in assessing goodwill for impairment. The valuation of goodwill for the second step of the goodwill impairment analysis is considered a Level 3 fair value measurement, which means that the valuation of the assets and liabilities reflect U. S. Steel's own assumptions about the assumptions that market participants would use in pricing the assets and liabilities.
	The valuation methodologies used for the 2013 impairment analysis to determine fair value under step one, with the assistance of a third party valuation specialist in the case of the Texas Operations reporting unit, were a market approach and an income approach.
	For purposes of the income approach, fair value was determined based on the present value of estimated future cash flows, discounted at an appropriate risk-adjusted rate (DCF analysis). U. S. Steel made assumptions about the amount and timing of future expected cash flows, terminal value growth rates and appropriate discount rates. The amount and timing of future cash flows within U. S. Steel’s DCF analysis was based on its most recent operational budgets, long range strategic plans and other estimates including probability weighting of cash flow scenarios. A three percent perpetual growth rate was used to calculate the value of cash flows beyond the last projected period in U. S. Steel’s DCF analysis and reflects its best estimates for stable, perpetual growth of its reporting units. Actual results may differ from those assumed in U. S. Steel’s forecasts. U. S. Steel used estimates of market participant weighted average cost of capital as a basis for determining the discount rates applied to its reporting units’ future expected cash flows, adjusted for risks and uncertainties inherent in the steel industry and in its internally developed forecasts. A discount rate of 10 percent was used for both reporting units.
	The market approach is based upon an analysis of valuation metrics for companies comparable to each reporting unit. Fair values for the Flat-rolled and Texas Operations reporting units were estimated using an appropriate valuation multiple, as well as estimated normalized earnings and an estimated control premium.
	In order to validate the reasonableness of the estimated fair values of the reporting units as of the valuation date, a reconciliation of the aggregate fair values of all reporting units to market capitalization was performed using a reasonable control premium. We further validated the reasonableness of the estimated fair values of our reporting units using other valuation metrics that included data from U. S Steel's historical transactions as well as published industry analyst reports.
	Goodwill impairment tests in prior years indicated that goodwill was not impaired for any of U. S. Steel's reporting units and there were no triggering events since that time that necessitated an impairment test outside of the normal annual assessment.
	Amortizable intangible assets are amortized on a straight-line basis over their estimated useful lives and are detailed below:
				As of December 31, 2013												As of December 31, 2012
	(In millions)	Useful		Gross				Accumulated				Net				Gross		Accumulated		Net
		Lives		Carrying				Amortization				Amount				Carrying		Amortization		Amount
				Amount												Amount
	Customer relationships	22-23 Years		$	215			$	63			$	152			$	221	$	54	$	167
	Other	2-20 Years		23				12				11				22		11		11
	Total amortizable intangible assets			$	238			$	75			$	163			$	243	$	65	$	178
	The carrying amount of acquired water rights with indefinite lives as of December 31, 2013 and December 31, 2012 totaled $75 million. The water rights are tested for impairment annually in the third quarter. U. S. Steel performed a qualitative impairment evaluation of its water rights for 2013. The 2013 and prior year tests indicated the water rights were not impaired.
	During the year ended December 31, 2013, U. S. Steel acquired indefinite-lived intangible assets for $12 million and entered into an agreement to make future payments contingent upon certain factors. The aggregate purchase price was $36 million, and U. S. Steel allocated $33 million to indefinite-lived intangible assets, based upon their estimated fair value. The liability for contingent consideration will be reassessed each quarter. The maximum potential liability for contingent consideration is $53 million. As of December 31, 2013, U. S. Steel has recorded a liability of $24 million to reflect the estimated fair value of the contingent consideration. Contingent consideration was valued using a probability weighted discounted cash flow using both Level 2 inputs based on 2013 Standard and Poor’s Bond Guide as well Level 3, significant other unobservable inputs, based on internal forecasts and weighted average cost of capital derived from market data.
	Identifiable intangible assets with finite lives are reviewed for impairment whenever events or circumstances indicate that the carrying value may not be recoverable. During the third quarter of 2013, U. S. Steel completed a review of its identifiable intangible assets with finite lives and determined that the assets were not impaired.
	Amortization expense was $10 million for the year ended December 31, 2013 and $11 million for the years ended December 31, 2012 and 2011. The estimated future amortization expense of identifiable intangible assets during the next five years is $11 million in each year from 2014 to 2017 and $10 million for 2018.

StockBased_Compensation_Plans

Stock-Based Compensation Plans	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation Plans	'
	Stock-Based Compensation Plans
	On April 26, 2005, U. S. Steel’s stockholders approved the 2005 Stock Incentive Plan (2005 Stock Plan). The aggregate number of shares of U. S. Steel common stock that may be issued through April 26, 2020 under the 2005 Stock Plan is 15,450,000 shares, of which 2,609,897 shares are available as of December 31, 2013 for future grants. Generally, a share issued under the Plan pursuant to an award other than a stock option will reduce the number of shares available under the Stock Plan by 1.64 shares. The purposes of the 2005 Stock Plan are to attract, retain and motivate employees and non-employee directors of outstanding ability, and to align their interests with those of the stockholders of U. S. Steel. The Compensation & Organization Committee of the Board of Directors administers the plan pursuant to which they may make grants of stock options, restricted stock, restricted stock units (RSUs), performance awards, and other stock-based awards. Also, shares related to awards (i) that are forfeited, (ii) that terminate without shares having been issued or (iii) for which payment is made in cash or property other than shares are again available for awards under the plan; provided, however, that shares delivered to U. S. Steel or withheld for purposes of satisfying the exercise price or tax withholding obligations shall not again be available for awards.
	The following table summarizes the total stock-based compensation awards granted during the years 2013, 2012 and 2011:
			Executive Stock			Non-executive Stock			Restricted			Performance
			Options			Options			Stock			Awards
									Units
	2013 Grants		838,610			971,860			1,043,420			271,960
	2012 Grants		510,570			993,310			910,011			328,780
	2011 Grants		228,300			478,760			422,080			85,040
	Stock-based compensation expense
	The following table summarizes the total compensation expense recognized for stock-based compensation awards:
	(In millions, except per share amounts)		12/31/13				12/31/12				12/31/11
	Stock-based compensation expense recognized:
	Cost of sales		$	10			$	12			$	10
	Selling, general and administrative expenses		23				26				23
	Total		33				38				33
	Related deferred income tax benefit		12				14				12
	Decrease in net income		$	21			$	24			$	21
	Decrease in basic earnings per share		0.14				0.16				0.14
	Decrease in diluted earnings per share		0.14				0.16				0.14
	As of December 31, 2013, total future compensation cost related to nonvested stock-based compensation arrangements was $35 million, and the average period over which this cost is expected to be recognized is approximately 12 months.
	Stock options
	Compensation expense for stock options is recorded over the vesting period based on the fair value on the date of grant, as calculated by U. S. Steel using the Black-Scholes model and the assumptions listed below. The 2013, 2012 and 2011 awards vest ratably over a three-year service period and have a term of ten years. Stock options are generally issued at the market price of the underlying stock on the date of the grant. The 2013 executive grants, however, were issued at the greater of (1) the premium exercise price of $25 or (2) the market price on the grant date. Upon exercise of stock options, shares of U. S. Steel stock are issued from treasury stock.
	Black-Scholes Assumptions (a)		2013 Executive Grants				2013 Non-Executive Grants				2012 Grants			2011 Grants
	Grant date price per share of option award		$	18.62			$	18.64			$	22.28		$	45.81
	Exercise price per share of option award		$	25.03			$	18.64			$	22.28		$	45.81
	Expected annual dividends per share		$	0.2			$	0.2			$	0.2		$	0.2
	Expected life in years		5				5				5			5
	Expected volatility		66		%		67		%		68		%	64		%
	Risk-free interest rate		1.3		%		1		%		0.8		%	1.8		%
	Average grant date fair value per share of unvested option awards as calculated from above		$	8.44			$	9.7			$	11.93		$	24.39
	(a)The assumptions represent a weighted-average for all grants during the year.
	The expected annual dividends per share are based on the latest annualized dividend rate at the date of grant; the expected life in years is determined primarily from historical stock option exercise data; the expected volatility is based on the historical volatility of U. S. Steel stock; and the risk-free interest rate is based on the U.S. Treasury strip rate for the expected life of the option.
	The following table shows a summary of the status and activity of stock options for the year ended December 31, 2013:
			Shares			Weighted-				Weighted-		Aggregate
						Average				Average		Intrinsic
						Exercise Price				Remaining		Value
						(per share)				Contractual Term		(in millions)
										(in years)
	Outstanding at January 1, 2013		4,318,966			$	43.86
	Granted		1,810,470			$	21.6
	Exercised		(14,383	)		$	22.31
	Forfeited or expired		(907,765	)		$	35.36
	Outstanding at December 31, 2013		5,207,288			$	37.66			7.5		$	21
	Exercisable at December 31, 2013		2,634,676			$	51.34			6		3
	Exercisable and expected to vest at December 31, 2013		4,946,640			$	38.42			7.4		$	20
	The aggregate intrinsic value in the table above represents the total pretax intrinsic value (difference between our closing stock price on the last trading day of 2013 and the exercise price, multiplied by the number of in-the-money options). Intrinsic value changes are a function of the fair market value of our stock.
	The total intrinsic value of stock options exercised (i.e., the difference between the market price at exercise and the price paid by the employee to exercise the option) was de minimus during the years ended December 31, 2013 and 2012, and $3 million during the year ended December 31, 2011. The total amount of cash received by U. S. Steel from the exercise of options during the year ended December 31, 2013, and the related net tax benefit realized from the exercise of these options, were de minimus.
	Stock awards
	Compensation expense for nonvested stock awards is recorded over the vesting period based on the fair value at the date of grant.
	RSUs generally vest ratably over 3 years. Their fair value is the market price of the underlying common stock on the date of grant.
	Performance awards vest at the end of a three-year performance period as a function of U. S. Steel’s total shareholder return compared to the total shareholder return of a peer group of companies over the three-year performance period. Performance awards can vest at between zero and 200 percent of the target award. The fair value of the performance awards is calculated using a Monte-Carlo simulation.
	The following table shows a summary of the performance awards outstanding as of December 31, 2013, and their fair market value on the respective grant date:
	Performance Period		Fair Value				Minimum			Target			Maximum
			(in millions)				Shares			Shares			Shares
	2013 - 2016		$	6			—			271,960			543,920
	2012 - 2015		$	8			—			328,780			657,560
	2011 - 2014		$	6			—			85,040			170,080
	The following table shows a summary of the status and activity of nonvested stock awards for the year ended December 31, 2013:
			Restricted			Performance			Total			Weighted-
			Stock Units			Awards (a)						Average
												Grant-Date
												Fair Value
Nonvested at January 1, 2013		1,262,198			503,114			1,765,312			$	31.62
Granted		1,043,420			271,960			1,315,380			19.2
Vested		(530,827	)		—			(530,827	)		32.58
Performance adjustment factor (b)		—			(89,294	)		(89,294	)		57.02
Forfeited or expired		(282,533	)		(185,804	)		(468,337	)		23.34
Nonvested at December 31, 2013		1,492,258			499,976			1,992,234			$	23.97
(a)The number of shares shown for the performance awards is based on the target number of share awards.
(b)	Consists of adjustments to vested performance awards to reflect actual performance. The adjustments were required since the original grants of the awards were at 100 percent of the targeted amounts.
The following table presents information on RSUs and performance awards granted:
		2013				2012				2011
Number of awards granted		1,315,380				1,238,791				507,120
Weighted-average grant-date fair value per share		$	19.2			$	23.07			$	49.1
During the years ended December 31, 2013, 2012, and 2011, the total fair value of shares vested was $17 million, $16 million, and $15 million, respectively.

Derivative_Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Instruments	'
	Derivative Instruments
	U. S. Steel is exposed to foreign currency exchange rate risks as a result of our European and Canadian operations. USSE’s revenues are primarily in euros and costs are primarily in U.S. dollars and euros. USSC’s revenues and costs are denominated in both Canadian and U.S. dollars. In addition, foreign cash requirements have been and in the future may be funded by intercompany loans, creating intercompany monetary assets and liabilities in currencies other than the functional currency of the entities involved, which can affect income when remeasured at the end of each period.
	U. S. Steel uses euro forward sales contracts with maturities no longer than 12 months to exchange euros for U.S. dollars to manage our exposure to foreign currency exchange rate fluctuations. Derivative instruments are required to be recognized at fair value in the balance sheet. U. S. Steel has not elected to designate these euro forward sales contracts as hedges. Therefore, changes in their fair value are recognized immediately in the results of operations. The gains and losses recognized on the euro forward sales contracts may also partially offset the accounting remeasurement gains and losses recognized on intercompany loans.
	As of December 31, 2013, U. S. Steel held euro forward sales contracts with a total notional value of approximately $320 million. We mitigate the risk of concentration of counterparty credit risk by purchasing our forward sales contracts from several counterparties.
	Additionally, U. S. Steel uses fixed-price forward physical purchase contracts to partially manage our exposure to price risk related to the purchases of natural gas and certain nonferrous metals used in the production process. During 2013, 2012 and 2011, the forward physical purchase contracts for natural gas and nonferrous metals qualified for the normal purchases and normal sales exemption in ASC Topic 815 and were not subject to mark-to-market accounting.
	The following summarizes the location and amounts of the fair values related to derivatives included in U. S. Steel’s financial statements as of December 31, 2013 and 2012:
			Fair Value
	(In millions)	Balance Sheet	31-Dec-13			31-Dec-12
		Location
	Foreign exchange forward contracts	Accounts payable	$	11		$	12
	The following summarizes the location and amounts of the gains and losses related to derivatives included in U. S. Steel’s financial statements for the years ended December 31, 2013, 2012 and 2011:
		Statement of	Amount of Gain
		Operations	(Loss)
	(In millions)	Location	Year Ended December 31, 2013			Year Ended December 31, 2012			Year Ended December 31, 2011
	Foreign exchange forward contracts	Other financial costs	$	(14	)	$	(7	)	$	13
	In accordance with the guidance in ASC Topic 820 on fair value measurements and disclosures, the fair value of our euro forward sales contracts was determined using Level 2 inputs, which are defined as “significant other observable” inputs. The inputs used are from market sources that aggregate data based upon market transactions.

Debt

Debt	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Debt	'
	Debt
							December 31,
	(In millions)		Interest		Maturity		2013				2012
			Rates %
	2037 Senior Notes		6.65		2037		$	350			$	350
	2022 Senior Notes		7.5		2022		400				400
	2021 Senior Notes		6.875		2021		275				—
	2020 Senior Notes		7.375		2020		600				600
	2018 Senior Notes		7		2018		500				500
	2017 Senior Notes		6.05		2017		450				450
	2019 Senior Convertible Notes		2.75		2019		316				—
	2014 Senior Convertible Notes		4		2014		322				863
	Province Note (C$150 million)		1		2015		141				151
	Environmental Revenue Bonds		5.38 - 6.88		2015 - 2042		549				549
	Recovery Zone Facility Bonds		6.75		2040		70				70
	Fairfield Caster Lease				2022		35				35
	Other capital leases and all other obligations				2014 - 2020		—				1
	Amended Credit Agreement		Variable		2016		—				—
	USSK Revolver		Variable		2016		—				—
	USSK credit facilities		Variable		2015 - 2016		—				—
	Total Debt						4,008				3,969
	Less Province Note fair value adjustment						15				23
	Less unamortized discount						54				8
	Less short-term debt and long-term debt due within one year						323				2
	Long-term debt						$	3,616			$	3,936
	2021 Senior Notes
	On March 26, 2013, U. S. Steel issued $275 million of 6.875% Senior Notes due April 1, 2021 (2021 Senior Notes). U. S. Steel received net proceeds from the offering of $270 million after fees of $5 million related to the underwriting discount and third party expenses. The net proceeds from the issuance of the 2021 Senior Notes, together with the net proceeds of the concurrent 2019 Senior Convertible Notes offering (see below), were used to repurchase a portion of our 4.00% Senior Convertible Notes due May 15, 2014 (2014 Senior Convertible Notes). Interest on the 2021 Senior Notes is payable semi-annually on April 1st and October 1st of each year, commencing on October 1, 2013.
	U. S. Steel may redeem the 2021 Senior Notes, in whole or in part, at our option at any time and from time to time on or after April 1, 2017 at the redemption price for such notes set forth below 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 April 1 of the years indicated below:
	Year	Redemption Price
	2017	103.438	%
	2018	101.719	%
	2019 and thereafter	100	%
	2019 Senior Convertible Notes
	On March 26, 2013, U. S. Steel issued $316 million of 2.75% Senior Convertible Notes due April 1, 2019 (2019 Senior Convertible Notes). U. S. Steel received net proceeds from the offering of $306 million after fees of $10 million related to the underwriting discount and third party expenses. The net proceeds from the issuance of the 2019 Senior Convertible Notes, together with the net proceeds of the concurrent 2021 Senior Notes offering (see above), were used to repurchase a portion of our 2014 Senior Convertible Notes. Interest on the 2019 Senior Convertible Notes is payable semi-annually on April 1st and October 1st of each year, commencing on October 1, 2013.
	The initial conversion rate for the 2019 Senior Convertible Notes is 39.5491 shares of U. S. Steel common stock per $1,000 principal amount, equivalent to an initial conversion price of approximately $25.29 per share of common stock, subject to adjustment as defined in the 2019 Senior Convertible Notes. On the issuance date of the 2019 Senior Convertible Notes, the market price of U. S. Steel’s common stock was below the stated conversion price of $25.29 so there was no beneficial conversion option to the holders. Based on the initial conversion rate, the 2019 Senior Convertible Notes are convertible into 12,507,403 shares of U. S. Steel common stock and we reserved for the possible issuance of 16,259,615 shares, which is the maximum amount that could be issued upon conversion. Holders may convert their notes at their option prior to the close of business on the business day immediately preceding October 1, 2018 only under certain circumstances (as described in the 2019 Senior Convertible Notes). On or after October 1, 2018, until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 2019 Senior Convertible Notes at any time. Upon conversion, we will satisfy our conversion obligation by paying or delivering, as the case may be, cash, shares of our common stock or a combination of cash and shares of our common stock at our election. Any unconverted 2019 Senior Convertible Notes mature at par on April 1, 2019.
	U. S. Steel may not redeem the 2019 Senior Convertible Notes prior to April 5, 2017. On or after April 5, 2017, we may redeem for cash all or part of the 2019 Senior Convertible Notes, at our option, under certain circumstances. The redemption price will equal 100% of the principal amount of the 2019 Senior Convertible Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date.
	If U. S. Steel undergoes a fundamental change, as defined in the 2019 Senior Convertible Notes, holders may require us to repurchase the 2019 Senior Convertible Notes in whole or in part for cash at a price equal to 100% of the principal amount of the 2019 Senior Convertible Notes to be purchased plus any accrued and unpaid interest (including additional interest, if any) up to, but excluding the repurchase date.
	Although the 2019 Senior Convertible Notes were issued at par, for accounting purposes the proceeds received from the issuance of the notes are allocated between debt and equity to reflect the fair value of the conversion option embedded in the notes and the fair value of similar debt without the conversion option. As a result, $53 million of the gross proceeds of the 2019 Senior Convertible Notes was recorded as an increase in additional paid-in capital with the offsetting amount recorded as a debt discount. The debt discount will be amortized over the term of the 2019 Senior Convertible Notes using an interest rate of 6.2% (the estimated effective borrowing rate for nonconvertible debt at the time of issuance) which will accrete the carrying value of the notes to the principal amount at maturity. As of December 31, 2013, the remaining unamortized debt discount was $47 million and the net carrying amount of the 2019 Senior Convertible Notes was $269 million.
	Similar to our other senior notes, the 2019 Senior Convertible Notes and the 2021 Senior Notes contain covenants limiting our ability to create liens, to enter into sale-leaseback transactions and to consolidate, merge or transfer all, or substantially all of our assets. They also contain provisions requiring the purchase of the notes upon a change in control under certain specified circumstances, as well as other customary provisions. In addition, certain payment defaults on other indebtedness are a default under the 2019 Senior Convertible Notes.
	Issuance of Senior Notes due 2022
	On March 15, 2012, U. S. Steel issued $400 million of 7.50% Senior Notes due March 15, 2022 (2022 Senior Notes). U. S. Steel received net proceeds from the offering of $392 million after fees of $8 million related to the underwriting discount and third party expenses. The majority of the net proceeds from the issuance of the 2022 Senior Notes was used in April 2012 to redeem all of our $300 million of 5.65% Senior Notes due June 1, 2013.
	The 2022 Senior Notes are senior and unsecured obligations that rank equally in right of payment with all of our other existing and future senior indebtedness. U. S. Steel will pay interest on the notes semi-annually in arrears on March 15th and September 15th of each year. The 2022 Senior Notes were issued under U. S. Steel’s shelf registration statement and are not listed on any national securities exchange.
	Similar to our other senior notes, the 2022 Senior Notes restrict our ability to create certain liens, to enter into sale leaseback transactions and to consolidate, merge, transfer or sell all, or substantially all of our assets. They also contain provisions requiring the purchase of the 2022 Senior Notes upon a change of control under certain specified circumstances, as well as other customary provisions.
	U. S. Steel may redeem the 2022 Senior Notes, in whole or in part, at our option at any time or from time to time on or after March 15, 2017 at the redemption price for such notes set forth below 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 March 15 of the years indicated below:
	Year	Redemption Price
	2017	103.75	%
	2018	102.5	%
	2019	101.25	%
	2020 and thereafter	100	%
	Senior Notes
	On March 16, 2010, U. S. Steel issued $600 million of 7.375 percent Senior Notes due 2020 (2020 Senior Notes). The 2020 Senior Notes were issued at 99.125 percent of their principal amount. U. S. Steel received net proceeds of $582 million after fees of $13 million for the underwriting discount and third party expenses. Interest is payable semi-annually on April 1st and October 1st of each year. The 2020 Senior Notes are not listed on any national securities exchange. The 2020 Senior Notes contain covenants limiting our ability to create liens, to enter into sale-leaseback transactions and to consolidate, merge or transfer all, or substantially all of our assets. They also contain provisions requiring the purchase of the 2020 Notes upon a change of control under certain specified circumstances, as well as other customary provisions.
	On December 10, 2007, U. S. Steel issued $500 million of 7.00 percent Senior Notes due 2018 (2018 Senior Notes). Interest is payable semi-annually on February 1st and August 1st of each year. The 2018 Senior Notes are not listed on any national securities exchange. The 2018 Senior Notes contain covenants limiting our ability to create liens, to enter into sale-leaseback transactions and to consolidate, merge or transfer all, or substantially all of our assets. They also contain provisions requiring the purchase of the 2018 Notes upon a change of control under certain specified circumstances, as well as other customary provisions.
	On May 21, 2007, U. S. Steel issued a total of $1,100 million of senior notes consisting of $350 million at 6.65 percent due 2037, $450 million at 6.05 percent due 2017, and $300 million at 5.65 percent due 2013, collectively, the Senior Notes (and individually, the 2037 Senior Notes, the 2017 Senior Notes and the 2013 Senior Notes, respectively). Interest is payable semi-annually on June 1st and December 1st of each year. All of the $300 million 5.65 percent Senior Notes due June 1, 2013 were redeemed in April 2012 as noted above. The Senior Notes are not listed on any national securities exchange. The Senior Notes contain covenants limiting our ability to create liens, to enter into sale-leaseback transactions and to consolidate, merge or transfer all, or substantially all of our assets. They also contain provisions requiring the purchase of the Senior Notes upon a change of control under certain specified circumstances, as well as other customary provisions.
	2014 Senior Convertible Notes
	On May 4, 2009, U. S. Steel issued $863 million of 4.00% Senior Convertible Notes due May 15, 2014 (Senior Convertible Notes). The Senior Convertible Notes are senior and unsecured obligations that rank equally with
	U. S. Steel’s other existing and future senior and unsecured indebtedness. Interest on the Senior Convertible Notes is payable semi-annually on May 15th and November 15th of each year. The Senior Convertible Notes are not listed on any national securities exchange.
	U. S. Steel may not redeem the Senior Convertible Notes prior to their maturity date. Holders may convert their Senior Convertible Notes into shares of U. S. Steel common stock at their option at any time prior to the close of business on the second scheduled trading day immediately preceding the maturity date of May 15, 2014. The initial conversion rate for the Senior Convertible Notes is 31.3725 shares of U. S. Steel common stock per $1,000 principal amount of Senior Convertible Notes, equivalent to an initial conversion price of approximately $31.875 per share of common stock, subject to adjustment as defined in the Senior Convertible Notes. On the issuance date of the Senior Convertible Notes, the market price of U. S. Steel’s common stock was below the stated conversion price of $31.875 and therefore, there was no beneficial conversion option to the holders. Based on the initial conversion rate, the Senior Convertible Notes are convertible into 27,058,781 shares of U. S. Steel common stock and we reserved for the possible issuance of 33,824,000 shares, which is the maximum amount that could be issued upon conversion. Other than receiving cash in lieu of fractional shares, holders do not have the option to receive cash upon conversion.
	If U. S. Steel undergoes a fundamental change, as defined in the Senior Convertible Notes, holders may require us to repurchase the Senior Convertible Notes in whole or in part for cash at a price equal to 100% of the principal amount of the Senior Convertible Notes to be purchased plus any accrued and unpaid interest (including additional interest, if any) up to, but excluding the repurchase date.
	The Senior Convertible Notes contain covenants limiting our ability to create liens, to enter into sale-leaseback transactions and to consolidate, merge or transfer all, or substantially all of our assets. They also contain provisions requiring the purchase of the Senior Convertible Notes upon a change of control under certain specified circumstances, as well as other customary provisions. In addition, certain payment defaults on other indebtedness are a default under the Senior Convertible Notes.
	In March 2013, U. S. Steel repurchased approximately $542 million aggregate principal amount of our 4.0% Senior Convertible Notes due 2014, reducing the outstanding principal amount of the notes to $322 million.
	The repurchases were funded with the net proceeds from the 2021 Senior Notes and the 2019 Senior Convertible Notes and cash. The aggregate purchase price, including accrued and unpaid interest and fees, for the convertible notes repurchased was approximately $580 million. U. S. Steel recorded a pretax charge of $34 million to net interest and other financial costs during 2013 related mainly to the repurchase premiums.
	Province Note
	In its acquisition of Stelco on October 31, 2007, U. S. Steel assumed a note that Stelco had issued to the Province of Ontario, Canada. The face amount of the Province Note is C$150 million (approximately $141 million and $151 million at December 31, 2013 and 2012) and is payable on December 31, 2015. The Province Note is unsecured and is subject to a 75 percent discount if the solvency deficiencies in the four main Stelco pension plans (see Note 16) are eliminated on or before the maturity date. The Province Note bears interest at a rate of one percent per annum and is payable semi-annually. Upon the acquisition, the Province Note was recorded at its present value of amounts to be paid using a current interest rate, in accordance with FAS 141. The Province Note will be accreted up to its face value over its term assuming an effective interest rate of 6.67 percent.
Obligations relating to Environmental Revenue Bonds
At December 31, 2013, U. S. Steel is the obligor on $549 million of Environmental Revenue Bonds. On August 17, 2012, U. S. Steel entered into loan agreements with several local authorities in connection with the issuance and sale of $94 million of Environmental Revenue Bonds due August 1, 2042 (2042 Environmental Revenue Bonds) to fund certain capital projects at our Gary Works, Clairton Plant and Granite City Works. The net proceeds from the sale of the 2042 Environmental Revenue Bonds were $93 million after fees of $1 million and are reflected as restricted cash in other noncurrent assets and become unrestricted as capital expenditures for these projects are made. At December 31, 2013, $43 million of this restricted cash remained. The interest rate on the loans is 5.75 percent and interest is payable semi-annually on February 1st and August 1st of each year.
Recovery Zone Facility Bonds
On December 1, 2010, U. S. Steel entered into a loan agreement in connection with the issuance and sale by the Lorain County Port Authority of $70 million of Lorain County Port Authority Recovery Zone Facility Revenue Bonds (Recovery Zone Bonds). The proceeds from the sale of the Recovery Zone Bonds were used to fund a capital project at our Lorain Tubular Operations in Ohio. The interest rate on the loan is 6.75 percent and interest is payable semi-annually on June 1st and December 1st of each year.
Fairfield Caster Lease
U. S. Steel is the lessee of a slab caster at Fairfield Works in Alabama. In December 2012, U. S. Steel exercised an option to renew the lease for a nine year term and purchase the facility at the expiration of the renewal period in June 2022.
Amended Credit Agreement
On July 20, 2011, U. S. Steel entered into an amendment and restatement of its $750 million Credit Agreement dated June 12, 2009 (Amended Credit Agreement) which increased the facility to $875 million, extended the term to July 20, 2016, added a minimum liquidity requirement to address the maturity of the 4% Senior Convertible Notes due in May 2014, reduced the fixed charge coverage ratio and increased the availability by $25 million prior to its measurement and made amendments to other terms and conditions. The Amended Credit Agreement is secured with a security interest in the majority of U. S. Steel’s domestic inventory, certain accounts receivable and related collateral.
The Amended Credit Agreement establishes a borrowing base formula, which limits the amounts U. S. Steel can borrow to a percent of the value of certain domestic inventory less specified reserves.
The Amended Credit 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.
As of December 31, 2013, there were no amounts drawn on the Amended Credit Agreement and inventory values calculated in accordance with the Amended Credit Agreement supported the full $875 million of the facility. Under the Amended Credit Agreement, U. S. Steel must maintain a fixed charge coverage ratio (as further defined in the Amended Credit Agreement) of at least 1.00 to 1.00 for the most recent four consecutive quarters when availability under the Amended Credit Agreement is less than the greater of 10.0% of the total aggregate commitments and $87.5 million. Since availability was greater than $87.5 million, compliance with the fixed charge coverage ratio covenant was not applicable. Based on the most recent four quarters as of December 31, 2013, we would not meet this covenant. If the value of inventory does not support the full amount of the facility or we are not able to meet this covenant in the future, the full amount of this facility would not be available to the Company.
In addition, beginning on February 13, 2014 and extending until the repayment or conversion of the $322 million of 4.00% Senior Convertible Notes, we must maintain minimum liquidity (as further defined in the Amended Credit Agreement) of at least $175 million. The minimum liquidity must include at least $145 million of availability under the Amended Credit Agreement.
Receivables Purchase Agreement
U. S. Steel has a Receivables Purchase Agreement (RPA) under which trade accounts receivable are sold, on a daily basis without recourse, to U. S. Steel Receivables, LLC (USSR), a wholly owned, bankruptcy-remote, special purpose entity used only for the securitization program. As U. S. Steel accesses this facility, USSR sells senior undivided interests in the receivables to a third-party and a third-party commercial paper conduit, while maintaining a subordinated undivided interest in a portion of the receivables. U. S. Steel has agreed to continue servicing the sold receivables at market rates.
At both December 31, 2013 and 2012, eligible accounts receivable supported $625 million of availability under the RPA. There were no receivables sold to third-parties under this facility at both December 31, 2013 and December 31, 2012. The subordinated retained interest at both December 31, 2013 and December 31, 2012 was $625 million with availability at December 31, 2013 of $572 million due to approximately $53 million of letters of credit outstanding.
USSR pays the third parties a discount based on the third-parties’ borrowing costs plus incremental fees. We paid $3 million and $4 million, in 2013 and 2012 respectively, relating to fees on the RPA. These costs are included in other financial costs in the statement of operations.
Generally, the facility provides that as payments are collected from the sold accounts receivables, USSR may elect to have the third-parties reinvest the proceeds in new eligible accounts receivable. As there was no activity under this facility during 2013, there were no collections reinvested. During 2012 collections of eligible accounts receivable of $1,175 million were reinvested.
The table below summarizes the trade receivables at December 31, 2013 and 2012, for USSR:
(In millions)		2013				2012
Balance of accounts receivable-net, eligible for sale to third-parties		$	988			$	1,127
Accounts receivable sold to third-parties		—				—
Balance included in Receivables on the balance sheet of U. S. Steel		$	988			$	1,127
The net book value of U. S. Steel’s retained interest in the receivables represents the best estimate of the fair market value due to the short-term nature of the receivables. The retained interest in the receivables is recorded net of the allowance for bad debts, which historically have not been significant.
The facility may be terminated on the occurrence and failure to cure certain events, including, among others, failure of USSR to maintain certain ratios related to the collectability of the receivables and failure to make payment under its material debt obligations, and may also be terminated upon a change of control. The facility expires in July 2016.
U. S. Steel Košice (USSK) credit facilities
At both December 31, 2013 and 2012, USSK had no borrowings under its €200 million (approximately $276 million and $264 million, respectively) unsecured revolving credit facility.
On July 15, 2013, USSK entered into a €200 million revolving credit facility agreement (the Credit Agreement) that replaced USSK's €200 million credit facility that was scheduled to expire in August 2013. The Credit Agreement contains certain USSK financial covenants (as further defined in the Credit Agreement), including maximum Leverage, maximum Net Debt to Tangible Net Worth, and minimum Interest Cover ratios. The covenants are measured semi-annually for the period covering the last twelve calendar months. USSK may not draw on the Credit Agreement if it does not comply with any of the financial covenants until the next measurement date. The Credit Agreement expires in July 2016.
USSK has a €20 million (approximately $27 million at December 31, 2013) unsecured revolving credit facility that expires in December 2015.
On December 6, 2013, USSK entered into a €10 million (approximately $14 million at December 31, 2013) unsecured credit facility that expires in December 2016. The credit facility contains certain USSK financial covenants as further defined within the facility as well as other customary terms and conditions.
At December 31, 2013, USSK had no borrowings under its €20 million and €10 million unsecured credit facilities (collectively approximately $41 million) and the availability was approximately $38 million due to approximately $3 million of customs and other guarantees outstanding. At December 31, 2012, USSK had no borrowings under its €20 million credit facility (which approximated $26 million) and the availability was approximately $24 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. USSK is the sole obligor on the facilities and is obligated to pay a commitment fee on the undrawn portion of the facilities.
Change in control event
If there is a change in control of U. S. Steel, the following may occur: (a) debt obligations totaling $3,212 million as of December 31, 2013 (including the Senior Notes and Senior Convertible Notes) may be declared immediately due and payable; (b) the Amended Credit Agreement, the RPA and USSK’s €200 million revolving credit agreement may be terminated and any amounts outstanding declared immediately due and payable; and (c) U. S. Steel may be required to either repurchase the leased Fairfield Works slab caster for $39 million or provide a letter of credit to secure the remaining obligation.
Debt Maturities – Aggregate maturities of debt are as follows (in millions):
2014				2015				2016				2017		2018		Later		Total
																Years
$	323			$	189			$	45			$	500	$	503	$	2,433	$	3,993	(a)
(a)Debt maturities include the Province Note fair value adjustment discussed above.

2012_Labor_Agreements

2012 Labor Agreements	12 Months Ended
	Dec. 31, 2013
2012 Labor Agreements Disclosure [Abstract]	'
2012 Labor Agreements	'
	2012 Labor Agreements
	Effective September 1, 2012, U. S. Steel and its U. S. Steel Tubular Products, Inc. subsidiary reached new labor agreements with the United Steelworkers (USW), which cover approximately 16,600 employees at our flat-rolled, tubular, coke-making and iron ore operations in the United States (the 2012 Labor Agreements). The 2012 Labor Agreements expire on September 1, 2015. The agreements provided for a $2,000 lump sum payment that was paid to each covered active USW member in October 2012, which resulted in U. S. Steel recognizing a pretax charge of $35 million in the third quarter of 2012. The agreements also provide for a lump sum payment of $500, effective April 1, 2014, to each covered USW member active on that date which is being accrued over the requisite service period.
	The 2012 Labor Agreements contain no-strike provisions and include wage increases of 2.0 percent on September 1, 2013 and 2.5 percent on January 1, 2015. The 2012 Labor Agreements also provide for pension and other benefit changes for both current employees and retirees (see Note 16).

Pensions_and_Other_Benefits

Pensions and Other Benefits	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Pensions and Other Benefits	'
	Pensions and Other Benefits
	U. S. Steel has defined contribution or multi-employer retirement benefits for more than half of its North American employees and non-contributory defined benefit pension plans covering the remaining North American employees. In the United States, benefits under the defined benefit pension plans are based upon years of service and final average pensionable earnings, or a minimum benefit based upon years of service, whichever is greater. In addition, pension benefits for most salaried employees in the United States under these plans are based upon a percent of total career pensionable earnings. Most salaried employees in the United States, including those not participating in the defined benefit pension plans of the Company, participate in defined contribution plans
	(401(k) plans) whereby the Company matches a certain percentage of salary based on the amount contributed by the participant. For those without defined benefit coverage, the Company also provides a retirement account benefit based on salary and attained age. The main U. S. Steel defined benefit pension plan was closed to new participants in 2003. At December 31, 2013, approximately 60 percent of U. S. Steel’s union employees in the United States are covered by the Steelworkers Pension Trust (SPT), a multi-employer pension plan, to which U. S. Steel contributes on the basis of a fixed dollar amount for each hour worked.
	The majority of employees and retirees of USSC participate in defined benefit pension plans and retiree health and life insurance plans. The majority of USSC union employees participate in defined benefit pension plans for which benefits are based upon years of service multiplied by a flat dollar rate. The main Hamilton bargaining unit defined benefit pension plan was closed to new entrants effective October 15, 2011, and the main Lake Erie bargaining unit defined benefit pension plan was closed to new entrants effective April 16, 2010. Hamilton and Lake Erie union employees hired on or after those respective dates are covered by defined contribution arrangements. The salaried Hamilton and Lake Erie defined benefit pension plans were closed to new participants in 1997 and currently less than half of active salaried USSC employees participate in these plans where benefits are based on final average pensionable earnings or a flat dollar rate. The balance of salaried employees participates in defined contribution arrangements.
	U.S. Steel’s defined benefit retiree health care and life insurance plans (Other Benefits) cover the majority of its employees in North America upon their retirement. Health care benefits are provided through hospital, surgical, major medical and drug benefit provisions or through health maintenance organizations, both subject to various cost sharing features, and in most cases domestically, an employer cap on total costs. Upon their retirement, most salaried employees in the United States are provided with a flat dollar pre-Medicare benefit and a death benefit.
	The majority of U. S. Steel’s European employees are covered by government-sponsored programs into which U. S. Steel makes required contributions. Also, U. S. Steel sponsors defined benefit plans for most European employees covering benefit payments due to employees upon their retirement, some of which are government mandated. These same employees receive service awards throughout their careers based on stipulated service and, in some cases, age and service.
	U. S. Steel uses a December 31 measurement date for its plans and may have an interim measurement date if significant events occur. Details relating to Pension Benefits and Other Benefits are below.
			Pension Benefits								Other Benefits
	(In millions)		2013				2012				2013			2012
	Change in benefit obligations
	Benefit obligations at January 1		$	11,347			$	10,770			$	3,940		$	4,186
	Service cost		128				118				27			28
	Interest cost		403				467				141			170
	Plan amendments		—				29				—			(522		)
	Actuarial losses (gains)		(421		)		848				(420		)	375
	Exchange rate loss (gain)		(234		)		81				(55		)	19
	Settlements, curtailments and termination benefits		(16		)		(28		)		—			—
	Benefits paid		(950		)		(938		)		(255		)	(316		)
	Benefit obligations at December 31		$	10,257			$	11,347			$	3,378		$	3,940
	Change in plan assets
	Fair value of plan at January 1		$	8,659			$	8,353			$	1,732		$	1,473
	Actual return on plan assets		1,363				945				346			196
	Employer contributions		226				234				10			76
	Exchange rate gain (loss)		(187		)		56				—			—
	Benefits paid from plan assets		(939		)		(929		)		(118		)	(13		)
	Fair value of plan assets at December 31		$	9,122			$	8,659			$	1,970		$	1,732
	Funded status of plans at December 31		$	(1,135	)		$	(2,688	)		$	(1,408	)	$	(2,208	)
	Amounts recognized in accumulated other comprehensive loss:
							2013
	(In millions)		12/31/12				Amortization				Activity			12/31/13
	Pensions
	Prior Service Cost		$	99			$	(24	)		$	1		$	76
	Actuarial losses		4,656				(367		)		(1,165		)	3,124
	Other Benefits
	Prior Service Cost		(180		)		13				—			(167		)
	Actuarial Losses		613				(31		)		(632		)	(50		)
	As of December 31, 2013 and 2012, the following amounts were recognized in the balance sheet:
			Pension Benefits								Other Benefits
	(In millions)		2013				2012				2013			2012
	Noncurrent assets		$	23			$	11			$	—		$	—
	Current liabilities		(298		)		(245		)		(337		)	(360		)
	Noncurrent liabilities		(860		)		(2,454		)		(1,071		)	(1,848		)
	Accumulated other comprehensive loss (a)		3,200				4,755				(217		)	433
	Net amount recognized		$	2,065			$	2,067			$	(1,625	)	$	(1,775	)
	(a)	Accumulated other comprehensive loss effects associated with accounting for pensions and other benefits in accordance with ASC Topic 715 at December 31, 2013 and December 31, 2012, respectively, are reflected net of tax of $886 million and $1,568 million respectively, on the Statement of Stockholders’ Equity.
	The Accumulated Benefit Obligation (ABO) for all defined benefit pension plans was $9,798 million and $10,817 million at December 31, 2013 and 2012, respectively.
			December 31,
	(In millions)		2013				2012
	Information for pension plans with an accumulated benefit obligation in excess of plan assets:
	Aggregate accumulated benefit obligations (ABO)		$	(9,685	)		$	(10,782	)
	Aggregate projected benefit obligations (PBO)		(10,144		)		(11,313		)
	Aggregate fair value of plan assets		8,986				8,614
	The aggregate ABO in excess of plan assets reflected above is included in the payroll and benefits payable and employee benefits lines on the balance sheet.
	Following are the details of net periodic benefit costs related to Pension and Other Benefits:
			Pension Benefits											Other Benefits
	(In millions)		2013				2012				2011			2013				2012				2011
	Components of net periodic benefit cost:
	Service cost		$	128			$	118			$	111		$	27			$	28			$	25
	Interest cost		403				467				511			141				170				209
	Expected return on plan assets		(611		)		(614		)		(623		)	(131		)		(117		)		(105		)
	Amortization - prior service costs		24				22				21			(13		)		11				25
	- actuarial losses		367				352				352			31				8				5
	Net periodic benefit cost, excluding below		311				345				372			55				100				159
Multiemployer plans (a)		74				70				65			—				—				—
Settlement, termination and curtailment (gains)/losses		11				(3		)		6			—				—				—
Net periodic benefit cost		$	396			$	412			$	443		$	55			$	100			$	159
(a)	Primarily represents pension expense for the SPT covering USW employees hired from National Steel Corporation and new USW employees hired after May 21, 2003.
Prior to the 2012 Labor Agreements, profit-based amounts were used to reduce retiree medical premiums. This amount was recognized on a deferred basis and estimated as part of the actuarial calculations used to derive Other Benefit expense. Other Benefit expense in 2012 and 2011 included approximately $40 million in costs to reflect the profit-based payments.
Net periodic benefit cost for pensions and other benefits is projected to be approximately $330 million and approximately $15 million, respectively, in 2014. The pension cost projection includes $78 million of contributions to the SPT. The amounts in accumulated other comprehensive income that are expected to be recognized as components of net periodic benefit cost during 2014 are as follows:
(In millions)		Pension				Other
		Benefits				Benefits
		2014				2014
Amortization of actuarial loss/(gain)		$	282			$	(13	)
Amortization of prior service cost		22				(3		)
Total recognized from accumulated other comprehensive income		$	304			$	(16	)
Assumptions used to determine the benefit obligation at December 31 and net periodic benefit cost for the year ended December 31 are detailed below:
		Pension Benefits											Other Benefits
		2013						2012					2013						2012
		U.S.			International			U.S.			International		U.S.			International			U.S.			International
Actuarial assumptions used to determine benefit obligations at December 31:
Discount rate		4.5	%		4.5	%		3.75	%		3.75	%	4.5	%		4.5	%		3.75	%		3.75	%
Increase in compensation rate		4	%		3	%		4	%		3	%	4	%		3	%		4	%		3	%
		Pension Benefits
		2013						2012					2011
		U.S.			International			U.S.			International		U.S.			International
Actuarial assumptions used to determine net periodic benefit cost for the year ended December 31:
Discount rate		3.75	%		3.75	%		4.5	%		4.5	%	5	%		5	%
Expected annual return on plan assets		7.75	%		7.25	%		7.75	%		7.25	%	8	%		7.5	%
Increase in compensation rate		4	%		3	%		4	%		3	%	4	%		3	%
		Other Benefits
		2013						2012					2011
		U.S.			International			U.S.			International		U.S.			International
Discount rate		3.75	%		3.75	%		4.5	%		4.5	%	5	%		5	%
Expected annual return on plan assets		7.75	%		n/a			7.75	%		n/a		8	%		n/a
Increase in compensation rate		4	%		3	%		4	%		3	%	4	%		3	%
The discount rate reflects the current rate at which the pension and other benefit liabilities could be effectively settled at the measurement date. In setting the domestic rates, we utilize several AAA and AA corporate bond indices as an indication of interest rate movements and levels. Based on this evaluation at December 31, 2013, U. S. Steel increased the discount rate used to measure both domestic Pension and Other Benefits obligations to 4.5 percent. For USSC benefit plans, a discount rate was selected through a similar review process using Canadian bond rates and indices and at December 31, 2013, U. S. Steel increased the discount rate to 4.5 percent for its Canadian-based pension and other benefits.
At December 31, 2013, due to a periodic review of the plans' mortality experience, the Company updated the mortality table used to calculate its main U.S. defined benefit pension and other postretirement benefit liabilities for formerly represented retirees. Previously, custom mortality tables based on plan experience, with no future mortality improvement, were used. As a result of the study, the prior table now assumes mortality improvement of 7 years from the date of liability measurement for this population and increased our projected benefit obligations by approximately $350 million.
		2013				2012
Assumed health care cost trend rates at December 31:		U.S.		Canada		U.S.		Canada
Health care cost trend rate assumed for next year		7.00%		6.00%		7.00%		6.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)		5.00%		5.00%		5.00%		5.00%
Year that the rate reaches the ultimate trend rate		2018		2018		2017		2017
A one-percentage-point change in the assumed return on plan assets, discount rate or health care cost trend rates would have the following effects:
(In millions)		1-Percentage-				1-Percentage-
		Point Increase				Point Decrease
Expected return on plan assets
Incremental (decrease) increase in:
Net periodic pension costs for 2014		$	(100	)		$	100
Discount rate
Incremental (decrease) increase in:
Net periodic pension & other benefits costs for 2014		$	(39	)		$	55
Pension & other benefits liabilities at December 31, 2013		$	(1,191	)		$	1,418
Health care cost escalation trend rates
Incremental increase (decrease) in:
Other postretirement benefit obligations		$	191			$	(161	)
Service and interest costs components		$	10			$	(8	)
U. S. Steel reviews its own actual historical rate experience and expectations of future health care cost trends to determine the escalation of per capita health care costs under U. S. Steel’s benefit plans. About two thirds of our costs for the domestic USW participants’ retiree health benefits in the Company’s main domestic benefit plan are limited to a per capita dollar maximum calculation based on 2006 base year actual costs incurred under the main U. S. Steel benefit plan for USW participants (cost cap). The full effect of the cost cap was deferred in the 2012 Labor Agreements until 2015. After 2015, the Company’s costs for a majority of USW retirees and their dependents are expected to remain fixed with the application of the cost cap and as a result, the cost impact of health care escalation for the Company is projected to be limited for this group.
In our Canadian retiree medical plans, most health care cost escalation results from the drug programs since most hospital and physician benefits are provided by the Government which incurs the escalation. Health care cost escalation applies to most other groups within the Company’s benefit plans, but does not apply to most domestic non-union retirees since their benefits are limited to flat dollar amounts or are not existent.
Plan Assets
ASC Topic 820 on fair value measurements includes a three-tier hierarchy as a framework for the inputs used in measuring fair value. The categories for determining fair market value are summarized below:
•Level 1 – quoted prices in active markets for identical investments
•Level 2 – other significant and observable comparable investments (including quoted prices for similar investments, interest rates, prepayment speeds, credit risk, etc.)
•Level 3 – investments lacking easily comparable data (including the plan’s own assumptions in determining the fair value of investments)
U. S. Steel’s Pension plan and Other Benefits plan assets are classified as follows:
Level 1		Level 2		Level 3
Investment Trusts		Internally Managed Partnerships		Private Equities
Exchange-traded Funds		Non-public Investment Partnerships		Timberlands
Short-term Investments		Debt Securities - U.S.		Real Estate
Equity Securities - U.S.		Debt Securities - Foreign		Mineral Interests
Equity Securities - Foreign		Pooled Funds
Government Bonds - U.S.		Government Bonds - Foreign
An instrument’s level is based on the lowest level of any input that is significant to the fair value measurement. Investments in investment trusts and exchange-traded funds are valued using a market approach at the closing price reported in an active market. Short term investments are valued at amortized cost which approximates fair value due to the short-term maturity of the instruments. Equity Securities – U.S. and Equity Securities – Foreign are valued at the closing price reported on the active exchange on which the individual securities are traded. Government Bonds – U.S. are valued by accepting a price from a public pricing source. Investments in Internally Managed Partnerships are valued using a market approach at the net asset value of units held, however investment opportunities in these partnerships are restricted to the benefit plans of U. S. Steel, its subsidiaries and current and former affiliates. Investments in non-public investment partnerships and pooled funds are valued using a market approach based on the aggregated value of the underlying investments. Government Bonds – Foreign, Debt Securities – U.S. and Debt Securities – Foreign are valued by accepting a price from a public pricing source or broker quotes. Private Equities are valued using information provided by external managers for each individual investment held in the fund. In 2013, real estate investments were valued using information provided by external managers. Timberland investments (and real estate investments in 2012) are either appraised or valued using the investment managers’ assessment of the assets within the fund. Mineral Interests are valued at the present value of estimated future cash flows discounted at estimated market rates for assets of similar quality and duration.
The following is a summary of U. S. Steel’s Pension plan assets carried at fair value at December 31, 2013 and 2012:
		Fair Value Measurements at December 31, 2013 (in millions)
		Total				Quoted Prices in				Significant			Significant
						Active Markets				Observable			Unobservable
						(Level 1)				Inputs			Inputs
										(Level 2)			(Level 3)
Asset Classes
Interest in Internally Managed Partnership – Fixed Income(a)		$	1,830			$	—			$	1,830		$	—
Interest in Internally Managed Partnership – Equity(b)		3,658				—				3,658			—
Interest in Investment Partnerships(c)		823				—				823			—
Equity securities – Foreign(d)		444				444				—			—
Pooled funds(e)		540				—				540			—
Timberlands		302				—				—			302
Private equities		306				—				—			306
Real estate		301				—				—			301
Other(f)		918				458				456			4
Total		$	9,122			$	902			$	7,307		$	913
(a)	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which United States Steel and Carnegie Pension Fund (UCF) acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
Debt Securities – U.S.	$	1,127
Government Bonds – U.S.	629
Agency Mortgages	65
Other	9
Total	$	1,830
(b)	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
Equity Securities – U.S.	$	3,346
Equity Securities – Foreign	181
Investment sales receivable	130
Other	1
Total	$	3,658
(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
(d)	Includes investments held in a diversified portfolio of Canadian equity securities with no single sector representing more than 30 percent of the portfolio by value.
(e)	Investments in funds incorporated in Canada that invest in diversified portfolios of global debt and equity securities.
(f)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes interests in investment trusts, exchange-traded funds, equity securities – U.S., short-term investments, government bonds - foreign, debt securities – foreign, mineral interests and miscellaneous receivables and payables.
		Fair Value Measurements at December 31, 2012 (in millions)
		Total				Quoted Prices in				Significant			Significant
						Active Markets				Observable			Unobservable
						(Level 1)				Inputs			Inputs
										(Level 2)			(Level 3)
Asset Classes
Interest in Internally Managed Partnership – Fixed Income(a)		$	1,688			$	—			$	1,688		$	—
Interest in Internally Managed Partnership – Equity(b)		3,491				—				3,491			—
Interest in Investment Partnerships(c)		608				—				608			—
Equity securities – Foreign(d)		482				482				—			—
Government bonds – Foreign(e)		499				—				499			—
Pooled funds(f)		312				—				312			—
Private equities		342				—				—			342
Real estate		300				—				—			300
Other(g)		937				503				193			241
Total		$	8,659			$	985			$	6,791		$	883
(a)	UCF Fixed Income Fund LP - a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
Debt Securities – U.S.	$	1,112
Government Bonds – U.S.	473
Agency Mortgages	85
Other	18
Total	$	1,688
(b)	UCF Equity Fund LP - a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
Equity Securities – U.S.	$	3,166
Equity Securities – Foreign	149
Investment sales receivable	111
Other	65
Total	$	3,491
(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
(d)	Includes investments held in a diversified portfolio of Canadian equity securities with no single sector representing more than 30 percent of the portfolio by value.
(e)	Includes investments in Canadian National and Provincial government bonds.
(f)	Investments in funds incorporated in Canada that invest in diversified portfolios of global debt and equity securities.
(g)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes interests in investment trusts, exchange-traded funds, short-term investments, government bonds – U.S., debt securities – U.S., debt securities – foreign, timberlands, mineral interests and miscellaneous receivables and payables.
The following table sets forth a summary of changes in the fair value of U. S. Steel’s Pension plan Level 3 assets for the years ended December 31, 2013 and 2012 (in millions):
		Other
		(Level 3 assets only)
		2013				2012
Balance at beginning of period		$	883			$	850
Transfers in and/or out of Level 3		—				—
Actual return on plan assets:
Realized gain		89				69
Net unrealized gain		45				8
Purchases, sales, issuances and settlements:
Purchases		102				98
Sales		(206		)		(142		)
Balance at end of period		$	913			$	883
The following is a summary of U. S. Steel’s Other Benefits plan assets carried at fair value at December 31, 2013 and 2012:
		Fair Value Measurements at December 31, 2013 (in millions)
		Total				Quoted Prices in				Significant			Significant
						Active Markets				Observable			Unobservable
						(Level 1)				Inputs			Inputs
										(Level 2)			(Level 3)
Asset Classes
Interest in Internally Managed Partnership – Fixed Income (a)		$	513			$	—			$	513		$	—
Interest in Internally Managed Partnership – Equity(b)		1,190				—				1,190			—
Interest in Investment Partnerships(c)		131				—				131			—
All Other(d)		136				37				—			99
Total		$	1,970			$	37			$	1,834		$	99
(a)	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
Debt Securities – U.S.	$	308
Government Bonds – U.S.	172
Agency Mortgages	18
Partner contribution receivable	19
Other	(4		)
Total	$	513
(b)	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
Equity Securities – U.S.	$	1,081
Equity Securities – Foreign	59
Exchange-traded funds	42
Other	8
Total	$	1,190
(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
(d)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes short-term investments, exchange-traded funds, private equities, real estate, timberlands and miscellaneous receivables and payables.
		Fair Value Measurements at December 31, 2012 (in millions)
		Total				Quoted Prices in				Significant			Significant
						Active Markets				Observable			Unobservable
						(Level 1)				Inputs			Inputs
										(Level 2)			(Level 3)
Asset Classes
Interest in Internally Managed Partnership – Fixed Income(a)		$	468			$	—			$	468		$	—
Interest in Internally Managed Partnership – Equity(b)		1,061				—				1,061			—
Interest in Investment Partnerships(c)		94				—				94			—
All Other(d)		109				38				—			71
Total		$	1,732			$	38			$	1,623		$	71
(a)	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
Debt Securities – U.S.	$	308
Government Bonds – U.S.	131
Agency Mortgages	24
Other	5
Total	$	468
(b)	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
Equity Securities – U.S.	$	950
Equity Securities – Foreign	45
Investment sales receivable	33
Other	33
Total	$	1,061
(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
(d)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes short-term investments, exchange-traded funds, private equities, real estate, timberlands and miscellaneous receivables and payables.
The following table sets forth a summary of changes in the fair value of U. S. Steel’s Other Benefits plan Level 3 assets for the years ended December 31, 2013 and 2012 (in millions):
		Other
		(Level 3 assets only)
		2013				2012
Balance at beginning of period		$	71			$	57
Transfers in and/or out of Level 3		—				—
Actual return on plan assets:
Realized gain		8				2
Net unrealized gain		6				3
Purchases, sales, issuances and settlements:
Purchases		29				17
Sales		(15		)		(8		)
Balance at end of period		$	99			$	71
U. S. Steel’s investment strategy for its U.S. pension and other benefits plan assets provides for a diversified mix of public equities, high quality bonds and selected smaller investments in private equities, investment trusts and partnerships, timber and mineral interests. For its U.S. Pension and Other Benefit plans, U. S. Steel has a target allocation for plan assets of 60 percent and 70 percent in equities, respectively, with the balance primarily invested in corporate bonds, Treasury bonds and government-backed mortgages. U. S. Steel believes that returns on equities over the long term will be higher than returns from fixed-income securities as actual historical returns from U. S. Steel’s trusts have shown. Returns on bonds tend to offset some of the short-term volatility of stocks. Both equity and fixed-income investments are made across a broad range of industries and companies to provide protection against the impact of volatility in any single industry as well as company specific developments. U. S. Steel will use a 7.75 percent assumed rate of return on assets for the development of net periodic cost for the main defined benefit pension plan and domestic OPEB plans in 2014. The 2014 assumed rate of return is the same as the rate of return used for 2013 domestic expense and was determined by taking into account the intended asset mix and some moderation of the historical premiums that fixed-income and equity investments have yielded above government bonds. Actual returns since the inception of the plans have exceeded this 7.75 percent rate and while recent annual returns have been volatile, it is U. S. Steel’s expectation that rates will achieve this level in future periods.
For USSC defined benefit pension plans, U. S. Steel’s investment strategy is similar to its strategy for U.S. plans, whereby the Company seeks a diversified mix of large and mid-cap equities, high quality corporate and government bonds and selected smaller investments with a target allocation for plan assets of 65 percent equities. U. S. Steel will use a 7.25 percent assumed rate of return on assets for the development of net periodic costs for the USSC defined benefit expense in 2014. This is lower than the U.S. pension plan assumption as subcategories within the asset mix are from a more limited investment universe and, as a result, have a lower expected return. The 2014 assumed rate of return is the same as the rate of return used for 2013 USSC expense.
Steelworkers Pension Trust
U. S. Steel participates in a multi-employer defined benefit pension plan, the Steelworkers Pension Trust (SPT). For most bargaining unit employees participating in the SPT, U. S. Steel contributes to the SPT a fixed dollar amount for each hour worked of $2.65; a rate agreed to as part of the 2012 Labor Agreements, which is set to expire on September 1, 2015. U. S. Steel’s contributions to the SPT represented greater than 5% of the total combined contributions of all employers participating in the plan for the years ended December 31, 2013, 2012 and 2011.
Participation in a multi-employer pension plan agreed to under the terms of a collective bargaining agreement differ from a traditional qualified single employer defined benefit pension plan. The SPT shares risks associated with the plan in the following respects:
a. Contributions to the SPT by U. S. Steel may be used to provide benefits to employees of other participating employers;
b. If a participating employer stops contributing to the SPT, the unfunded obligations of the plan may be borne by the remaining participating employers;
c. If U. S. Steel chooses to stop participating in the SPT, U. S. Steel may be required to pay an amount based on the underfunded status of the plan, referred to as a withdrawal liability.
On March 21, 2011 the Board of Trustees of the SPT elected funding relief which has the effect of decreasing the amount of required minimum contributions in near-term years, but will increase the minimum funding requirements during later plan years. As a result of the election of funding relief, the SPT’s zone funding under the Pension Protection Act may be impacted.
In addition to the funding relief election, the Board of Trustees also elected a special amortization rule, which allows the SPT to separately amortize investment losses incurred during the SPT’s December 31, 2008 plan year-end over a 29 year period, whereas they were previously required to be amortized over a 15 year period.
U. S. Steel’s participation in the SPT for the annual periods ended December 31, 2013, 2012 and 2011 is outlined in the table below.
		Employer		Pension				FIP/RP Status		U.S. Steel											Surcharge			Expiration Date
		Identification		Protection				Pending/		Contributions											Imposed(c)			of Collective
		Number/		Act Zone				Implemented(b)		(in millions)														Bargaining
		Pension Plan		Status as of																				Agreement
		Number		December 31(a)
Pension Fund				2013		2012				2013			2012				2011				2013		2012
Steelworkers Pension Trust		23-6648508/499		Green		Green		No		$	74		$	69			$	63			No		No	September 1, 2015
(a)	The zone status is based on information that U. S. Steel received from the plan and is certified by the plan’s actuary. Among other factors, plans in the green zone are at least 80 percent funded, while plans in the yellow zone are less than 80 percent funded and plans in the red zone are less than 65 percent funded.
(b)	Indicates if a financial improvement plan (FIP) or a rehabilitation plan (RP) is either pending or has been implemented.
(c)	Indicates whether there were charges to U. S. Steel from the plan.
Cash Flows
Employer Contributions – In addition to the contributions to the Steelworkers Pension Trust noted in the table above, U. S. Steel made voluntary contributions in 2013 of $140 million to its main defined benefit pension plan, $82 million in required contributions to the USSC plans and $30 million of pension payments not funded by trusts. In 2012, U. S. Steel made a $140 million voluntary contribution to its main defined benefit pension plan, $94 million in required contributions to the USSC plans and $20 million of pension payments not funded by trusts.
Cash payments totaling $137 million and $303 million were made for other postretirement benefit payments not funded by trusts in 2013 and 2012, respectively. The decrease in cash benefit payments not funded by trusts is due to the conversion of our Medicare eligible USW retirees to a fully insured plan and the utilization of assets previously contributed to our trust for represented retiree health care on a voluntary basis to pay retiree benefits during 2013. In addition, in 2013, we made a $10 million contribution to our trust for represented retiree health care and life insurance benefits; however, the $75 million contribution to a restricted account within the same trust as required by collective bargaining agreements, that was due in December 2013 has been deferred until December 2016. U. S. Steel is similarly required to make $75 million contributions to that trust account during both 2014 and 2015 annual periods.
In conjunction with the acquisition of Stelco, now USSC, U. S. Steel assumed the pension plan funding agreement (the Pension Agreement) that Stelco had entered into with the Superintendent of Financial Services of Ontario (the Province) on March 31, 2006 that covers USSC’s four main pension plans. The Pension Agreement requires minimum contributions of C$70 million (approximately $67 million) per year in 2011 through 2015 plus additional annual contributions for benefit improvements, primarily related to union retiree indexing provisions. With the Hamilton Works and Lake Erie Works collective bargaining agreement settlements in 2011 and 2010, respectively, cost of living provisions are no longer provided through the pension plan covering former represented employees. The Pension Agreement remains in effect with its defined annual contributions as noted above until the earlier of full solvency funding for the four main plans or until December 31, 2015, when minimum funding requirements for the plans resume under the provincial pension legislation.
Estimated Future Benefit Payments – The following benefit payments, which reflect expected future service as appropriate, are expected to be paid from U. S. Steel’s defined benefit plans:
(In millions)		Pension				Other
		Benefits				Benefits
2014		$	955			$	266
2015		808				285
2016		796				280
2017		789				241
2018		771				232
Years 2019 - 2023		3,563				1,077
Defined contribution plans
U. S. Steel also contributes to several defined contribution plans for its salaried employees. Approximately 66% of non-union salaried employees in North America receive pension benefits through a defined contribution pension plan with contribution percentages based on age, for which company contributions totaled $19 million, $17 million and $15 million in 2013, 2012 and 2011, respectively. U. S. Steel’s matching contributions to salaried employees’ defined contribution savings fund plans, which for the most part are based on a percentage of the employees’ contributions, totaled $23 million in 2013, $21 million in 2012 and $20 million in 2011. Most union employees are eligible to participate in a defined contribution savings fund plan where there is no company match on savings except for certain Canadian and Tubular hourly employees whose company contributions totaled $3 million in 2013 and 2012 and $2 million in 2011. U. S. Steel also maintains a supplemental thrift plan to provide benefits which are otherwise limited by the Internal Revenue Service for qualified plans. U. S. Steel’s costs under these defined contribution plans totaled $2 million in 2013, $1 million in 2012 and $2 million in 2011.
Other postemployment benefits
The Company provides benefits to former or inactive employees after employment but before retirement. Certain benefits including workers’ compensation and black lung benefits represent material obligations to the Company and under the guidance for nonretirement postemployment benefits, have historically been treated as accrued benefit obligations, similar to the accounting treatment provided for pensions and other benefits. APBO liabilities for these benefits recorded at December 31, 2013, totaled $122 million as compared to $102 million at December 31, 2012. APBO amounts were developed assuming a discount rate of 4.50 percent and 3.75 percent at December 31, 2013 and 2012. Net periodic benefit cost for these benefits is projected to be $16 million in 2014 compared to $13 million in 2013 and $12 million in 2012. The projected cost in 2014 includes $1 million in unrecognized actuarial losses that will be recorded against accumulated other comprehensive income.
Pension Funding
In November 2013, U. S. Steel’s Board of Directors (the Board) authorized voluntary contributions to U. S. Steel’s trusts for pensions and other benefits of up to $300 million through the end of 2015.
In July 2012, pension stabilization legislation was enacted that includes a revised interest rate formula to be used to measure defined benefit pension obligations for calculating minimum annual contributions. The new interest rate formula results in higher interest rates for minimum funding calculations as compared to prior law over the next few years, which will improve the funded status of our main defined benefit pension plan and reduce minimum required contributions. U. S. Steel made voluntary contributions to our main U.S. defined benefit plan of $140 million in 2013 and 2012. U. S. Steel will likely make voluntary contributions of similar amounts in future periods in order to mitigate potentially larger mandatory contributions in later years. Assuming future asset performance consistent with our expected long-term earnings rate assumption of 7.75%, we anticipate that the pension stabilization legislation interest rate changes will allow us to continue to make voluntary contributions of approximately $140 million per year through 2015 before we could be required to contribute more than that amount should the current low interest rate environment persist.

Asset_Retirement_Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2013
Asset Retirement Obligation Disclosure [Abstract]	'
Asset Retirement Obligations	'
	Asset Retirement Obligations
	U. S. Steel’s asset retirement obligations (AROs) primarily relate to mine and landfill closure and post-closure costs. The following table reflects changes in the carrying values of AROs for the years ended December 31, 2013 and 2012:
		December 31,
	(In millions)	2013			2012
	Balance at beginning of year	$	33		$	38
	Additional obligations incurred	28			2
	Obligations settled	(7		)	(9		)
	Accretion expense	5			2
	Balance at end of period	$	59		$	33
	Certain AROs related to disposal costs of the majority of fixed assets at our integrated steel facilities have not been recorded because they have an indeterminate settlement date. These AROs will be initially recognized in the period in which sufficient information exists to estimate their fair value.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value of Financial Instruments	'
	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 Consolidated Balance Sheet approximate fair value. See Note 13 for disclosure of U. S. Steel’s derivative instruments, which are accounted for at fair value on a recurring basis.
	The following table summarizes U. S. Steel’s financial assets and liabilities that were not carried at fair value at December 31, 2013 and 2012.
		December 31, 2013				December 31, 2012
	(In millions)	Fair Value		Carrying		Fair Value		Carrying
				Amount				Amount
	Financial assets:
	Investments and long-term receivables (a)	$	63	$	63	$	39	$	39
	Financial liabilities:
	Debt (b)	$	4,198	$	3,904	$	4,113	$	3,902
	(a)Excludes equity method investments.
	(b)Excludes borrowings under the RPA and capital lease obligations.
	The following methods and assumptions were used to estimate the fair value of financial instruments included in the table above:
	Investments and long-term receivables: Fair value is based on Level 2 inputs which were discounted cash flows. U. S. Steel is subject to market risk and liquidity risk related to its investments.
	Long-term debt instruments: Fair value was determined using Level 2 inputs which were derived from quoted market prices and is based on the yield on public debt where available or current borrowing rates available for financings with similar terms and maturities.
	Fair value of the financial assets and liabilities disclosed herein is not necessarily representative of the amount that could be realized or settled, nor does the fair value amount consider the tax consequences of realization or settlement.
	Financial guarantees are U. S. Steel’s only unrecognized financial instrument. For details relating to financial guarantees see Note 24.

Reclassifications_from_Accumul

Reclassifications from Accumulated Other Comprehensive Income (Notes)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Reclassifications from Accumulated Other Comprehensive Income (AOCI)	'
	Reclassifications from Accumulated Other Comprehensive Income (AOCI)
	(in millions) (a)		Pension and				Foreign				Total
			Other Benefit				Currency
			Items				Items
	Balance at December 31, 2011		$	(3,598	)		$	231			$	(3,367	)
	Other comprehensive income (loss) before reclassifications		(278		)		114				(164		)
	Amounts reclassified from AOCI (b)		263				—				263
	Net current-period other comprehensive income		(15		)		114				99
	Balance at December 31, 2012		$	(3,613	)		$	345			$	(3,268	)
	Other comprehensive income (loss) before reclassifications		1,220				52				1,272
	Amounts reclassified from AOCI		266			(b)	(22		)	(c)	244
	Net current-period other comprehensive income		1,486				30				1,516
	Balance at December 31, 2013		$	(2,127	)		$	375			$	(1,752	)
	(a)All amounts are net of tax. Amounts in parentheses indicate debits.
	(b)See table below for further details.
	(c)Included in Income tax (benefit) provision line on the Consolidated Statement of Operations
					Amount reclassified
					from AOCI
	(In millions) (a)		Details about AOCI components		2013				2012
			Amortization of pension and other benefit items
			Prior service costs		$	(11	)		$	(33	)	(b)
			Actuarial gains/(losses)		(398		)		(360		)	(b)
			Total before tax		(409		)		(393		)
			Tax benefit		143				130
			Net of tax		$	(266	)		$	(263	)
	(a)Amounts in parentheses indicate debits to income/loss.
	(b)	These AOCI components are included in the computation of net periodic benefit cost (see Note 16 for additional details).

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2013
Supplemental Cash Flow Elements [Abstract]	'
Supplemental Cash Flow Information	'
	Supplemental Cash Flow Information
	(In millions)	2013			2012			2011
	Net cash used in operating activities included:
	Interest and other financial costs paid (net of amount capitalized)	$	(238	)	$	(239	)	$	(222	)
	Income taxes (paid) refunded	$	(20	)	$	(71	)	$	13
	Non-cash investing and financing activities:
	Change in accrued capital expenditures	$	(14	)	$	(52	)				(a)
	Assets acquired under capital lease	$	—		$	35		$	—
	U. S. Steel common stock issued for employee stock plans	$	—		$	2		$	—
	(a)The change in accrued capital expenditures was insignificant for the year ended December 31, 2011.

Transactions_with_Related_Part

Transactions with Related Parties	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
Transactions with Related Parties	'
	Transactions with Related Parties
	Net sales to related parties and receivables from related parties primarily reflect sales of steel products to equity investees. Generally, transactions are conducted under long-term market-based contractual arrangements. Related party sales and service transactions were $1,155 million, $1,303 million and $1,258 million in 2013, 2012 and 2011, respectively.
	Purchases from related parties for outside processing services provided by equity investees amounted to $67 million, $58 million and $54 million during 2013, 2012 and 2011, respectively. Purchases of iron ore pellets from related parties amounted to $246 million, $298 million and $215 million for the years ended December 31, 2013, 2012 and 2011, respectively.
	Accounts payable to related parties include balances due to PRO-TEC Coating Company (PRO-TEC) of $70 million and $75 million at December 31, 2013 and 2012, respectively for invoicing and receivables collection services provided by U. S. Steel. U. S. Steel, as PRO-TEC’s exclusive sales agent, is responsible for credit risk related to those receivables. U. S. Steel also provides PRO-TEC marketing, selling and customer service functions. Payables to other related parties totaled $3 million at both December 31, 2013 and 2012.

Leases

Leases	12 Months Ended
	Dec. 31, 2013
Leases [Abstract]	'
Leases	'
	Leases
	Future minimum commitments for capital leases (including sale-leasebacks accounted for as financings) and for operating leases having initial non-cancelable lease terms in excess of one year are as follows:
	(In millions)	Capital		Operating
		Leases		Leases
	2014	$	5	$	76
	2015	5		71
	2016	5		63
	2017	5		45
	2018	5		14
	Later years	26		31
	Sublease rentals	—		—
	Total minimum lease payments	$	51	$	300
	Less imputed interest costs	16
	Present value of net minimum lease payments included in long-term debt (see Note 14)	$	35
	Operating lease rental expense:
	(In millions)	2013		2012		2011
	Minimum rentals	$	111	$	91	$	95
	Contingent rentals	11		12		11
	Sublease rentals	—		—		—
	Net rental expense	$	122	$	103	$	106
	U. S. Steel leases a wide variety of facilities and equipment under operating leases, including land and building space, office equipment, production equipment and transportation equipment. Most long-term leases include renewal options and, in certain leases, purchase options. See the discussion of residual value guarantees under “other contingencies” in Note 24. Contingent rental payments are determined based on operating lease agreements that include floating rental charges that are directly associated to variable operating components.

Restructuring_and_Other_Charge

Restructuring and Other Charges	12 Months Ended
	Dec. 31, 2013
Restructuring and Related Activities [Abstract]	'
Restructuring and Other Charges	'
	Restructuring and Other Charges
	During the fourth quarter of 2013, the Company implemented certain headcount reductions and production facility closures related to our iron and steelmaking facilities at Hamilton Works in Canada, barge operations related to Warrior and Gulf Navigation (WGN) in Alabama and administrative headcount reductions at our Hamilton Works and Lake Erie Works also in Canada. We closed our iron and steelmaking facilities at Hamilton Works effective December 31, 2013. Charges for restructuring and ongoing cost reduction initiatives are recorded in the period the Company commits to a restructuring or cost reduction plan, or executes specific actions contemplated by the plan and all criteria for liability recognition have been met. Charges related to the restructuring and cost reductions include severance costs, accelerated depreciation and other closure costs. These costs are not included in the measure of segment performance for any of our reportable segments (see Note 3). There were no such similar charges in 2012 or 2011.
	The activity in the accrued balances and the non-cash charges and credits incurred in relation to restructuring and other cost reduction programs during the year ended December 31, 2013 were as follows:
		Severance			Exit			Accelerated
	(in millions)	Accrual			Costs			Depreciation
	Balance at December 31, 2012	$	—		$	—		$	—
	Additional charges	16		(a)	6		(b)	222			(c)
	Cash payments/utilization	—			—			(222		)
	Other adjustments and re-classes	—			—			—
	Balance at December 31, 2013	$	16		$	6		$	—
	(a) Amount relates to charges recognized for severance benefits for approximately 180 employees terminated at Hamilton Works and Lake Erie Works and excludes associated pension curtailment charges of approximately $4 million (see Note 16).
	(b) Amount relates to exit costs associated with the closure of the WGN.
	(c) Accelerated depreciation charges are related to the closure of the iron and steelmaking facilities at Hamilton Works and assets related to WGN.
	Accrued liabilities for restructuring and other cost reduction programs are included in the following balance sheet lines:
	(in millions)	December 31, 2013			December 31, 2012
	Accounts payable	$	6		$	—
	Payroll and benefits payable	8			—
	Employee benefits	8			—
	Total	$	22		$	—

Contingencies_and_Commitments

Contingencies and Commitments	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Contingencies and Commitments	'
	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 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.
	Asbestos matters – As of December 31, 2013, U. S. Steel was a defendant in approximately 720 active cases involving approximately 3,320 plaintiffs. Many of these cases involve multiple defendants (typically from fifty to more than one hundred). About 2,560, or approximately 77 percent, of these claims are currently pending in jurisdictions which permitted filings with massive numbers of 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. During 2013, U. S. Steel paid approximately $11 million in settlements. These settlements and other dispositions resolved approximately 250 claims. New case filings in 2013 added approximately 240 claims. At December 31, 2012, U. S. Steel was a defendant in approximately 790 active cases involving approximately 3,330 plaintiffs. During 2012, U. S. Steel paid approximately $15 million in settlements. These settlements and other dispositions resolved approximately 190 claims. New case filings in 2012 added approximately 285 claims. Most claims filed in 2013 and 2012 involved individual or small groups of claimants as many jurisdictions no longer permit the filing of mass complaints.
	Historically, these claims against U. S. Steel fall into three major groups: (1) claims made by persons who allegedly were exposed to asbestos at U. S. Steel facilities (referred to as “premises claims”); (2) claims made by industrial workers allegedly exposed to products manufactured by U. S. Steel; and (3) claims made under certain federal and general maritime laws by employees of former operations of U. S. Steel. In general, the only insurance available to U. S. Steel with respect to asbestos claims is excess casualty insurance, which has multi-million dollar retentions. To date, U. S. Steel has received minimal payments under these policies relating to asbestos claims.
	These asbestos cases allege a variety of respiratory and other diseases based on alleged exposure to asbestos. U. S. Steel is currently a defendant in cases in which a total of approximately 270 plaintiffs allege that they are suffering from mesothelioma. The potential for damages against defendants may be greater in cases where the plaintiffs can prove mesothelioma.
	In many cases in which claims have been asserted against U. S. Steel, the plaintiffs have been unable to establish any causal relationship to U. S. Steel or our products or premises; however, with the decline in mass plaintiff cases, the incidence of claimants actually alleging a claim against U. S. Steel is increasing. In addition, in many asbestos cases, the plaintiffs have been unable to demonstrate that they have suffered any identifiable injury or compensable loss at all; that any injuries they have incurred did in fact result from alleged exposure to asbestos; or that such alleged exposure was in any way related to U. S. Steel or our products or premises.
	The amount U. S. Steel has accrued for pending asbestos claims is not material to U. S. Steel’s financial position. U. S. Steel does not accrue for unasserted asbestos claims because it is not possible to determine whether any loss is probable with respect to such claims or even to estimate the amount or range of any possible losses. The vast majority of pending claims against U. S. Steel allege so-called “premises” liability-based alleged exposure on U. S. Steel’s current or former premises. These claims are made by an indeterminable number of people such as truck drivers, railroad workers, salespersons, contractors and their employees, government inspectors, customers, visitors and even trespassers. In most cases the claimant also was exposed to asbestos in non-U. S. Steel settings; the relative periods of exposure between U. S. Steel and non-U. S. Steel settings vary with each claimant; and the strength or weakness of the causal link between U. S. Steel exposure and any injury vary widely as do the nature and severity of the injury claimed.
	We are unable to estimate the ultimate outcome of asbestos-related lawsuits, claims and proceedings due to the unpredictable nature of personal injury litigation. Despite this uncertainty, management believes that the ultimate resolution of these matters will not have a material adverse effect on U. S. Steel’s financial condition, although the resolution of such matters could significantly impact results of operations for a particular quarter. Among the factors considered in reaching this conclusion are: (1) it has been many years since U. S. Steel employed maritime workers or manufactured or sold asbestos containing products; (2) most asbestos containing material was removed or remediated at U. S. Steel facilities many years ago; and (3) U. S. Steel’s history of trial outcomes, settlements and dismissals.
	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:
		Twelve Months Ended December 31,
	(In millions)	2013			2012
	Beginning of period	$	203		$	206
	Accruals for environmental remediation deemed probable and reasonably estimable	45			13
	Payments	(15		)	(16		)
	End of period	$	233		$	203
	Accrued liabilities for remediation activities are included in the following balance sheet lines:
	(In millions)	December 31, 2013			December 31, 2012
	Accounts payable	$	17		$	21
	Deferred credits and other noncurrent liabilities	216			182
	Total	$	233		$	203
	Expenses related to remediation are recorded in cost of sales and totaled $45 million, $13 million and $36 million for the years ended December 31, 2013, 2012 and 2011, respectively. It is not presently 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 possible that total remediation costs for active matters may exceed the accrued liabilities by as much as 10 to 25 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, we categorize projects as follows:
	(1)Projects with Ongoing Study and Scope Development are those projects which are still in the study and 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 cost estimates cannot be determined. Therefore, significant costs, in addition to the accrued liabilities for these projects, are reasonably possible.
	(2)Significant Projects with Defined Scope are those projects with significant accrued liabilities, a defined scope and little likelihood of significant additional costs.
	(3)Other Projects are those projects with relatively small accrued liabilities for which we believe that, while additional costs are possible, they are not likely to be significant, and those projects for which we do not yet possess sufficient information to estimate potential costs to U. S. Steel.
	Projects with Ongoing Study and Scope Development – There are five environmental remediation projects where reasonably possible additional costs for completion are not currently estimable, but could be material. These projects are four Resource Conservation and Recovery Act (RCRA) programs (at Fairfield Works, Lorain Tubular, USS-POSCO Industries (UPI) and the Fairless Plant) and a voluntary remediation program at the former steelmaking plant at Joliet, Illinois. As of December 31, 2013, accrued liabilities for these projects totaled $2 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.
	Significant Projects with Defined Scope – As of December 31, 2013, a total of $54 million was accrued for projects at or related to Gary Works where the scope of work is defined.
	An additional project with defined scope greater than or equal to $5 million consists of a project at U. S. Steel’s former Geneva Works in Geneva, Utah. As of December 31, 2013, the accrued liability for this project totaled $64 million. U. S. Steel does not expect material additional costs related to this project.
	Additionally, the expanded scope of the St. Louis Estuary and Upland project and SWMU #4 project at UPI were defined in the fourth quarter of 2013 and a $32 million charge and $7 million charge, respectively, was recorded for the remediation. As of December 31, 2013, the accrued liability for these projects totaled $52 million and $7 million, respectively.
	Other Projects – There are six 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 December 31, 2013 was $13 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 had an accrued liability of less than $1 million. The total accrued liability for these projects at December 31, 2013 was $7 million. We do 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 $28 million at December 31, 2013 and were based on known scopes of work.
	Administrative and Legal Costs – As of December 31, 2013, U. S. Steel had an accrued liability of $6 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 bring existing facilities into compliance with various laws relating to the environment. In 2013 and 2012, such capital expenditures totaled $64 million and $53 million, respectively. U. S. Steel anticipates making additional such expenditures in the future; however, the exact amounts and timing of such expenditures are uncertain because of the continuing evolution of specific regulatory requirements.
	CO2 Emissions – Current and potential regulation of greenhouse gas (GHG) emissions remains a significant issue for the steel industry, particularly for integrated steel producers such as U. S. Steel. The regulation of carbon dioxide (CO2) emissions has either become law or is being considered by legislative bodies of many nations, including countries where we have operating facilities. The European Union (EU) has established GHG regulations based upon national allocations and a cap and trade system. In Canada, both the federal and Ontario governments have issued proposed requirements for GHG emissions. In the United States, the Environmental Protection Agency (EPA) has published rules for regulating GHG emissions for certain facilities and has implemented various reporting requirements as further described below. In 2010, GHG legislation was passed in the House of Representatives and introduced in the Senate. The federal courts are considering several suits that challenge the EPA’s authority to regulate GHG emissions under the Clean Air Act (CAA). We do not know what action, if any, may be taken by the current or future sessions of Congress.
	The European Commission (EC) has created an Emissions Trading System (ETS) and starting in 2013, the ETS began to employ centralized allocation, rather than national allocation plans, that are more stringent than the previous requirements. The ETS also includes a cap designed to achieve an overall reduction of GHGs for the ETS sectors of 21% in 2020 compared to 2005 emissions and auctioning as the basic principle for allocating emissions allowances, with some transitional free allocation provided on the basis of benchmarks for manufacturing industries under risk of carbon leakage. Manufacturing of sinter, coke oven products, basic iron and steel, ferro-alloys and cast iron tubes have all been recognized as exposing companies to a significant risk of carbon leakage, but the ETS is still expected to lead to additional costs for steel companies in Europe. The EU has imposed limitations under the ETS for the period 2013-2020 (Phase III) that are more stringent than those in NAP II, reducing the number of free allowances granted to companies to cover their CO2 emissions.
	In September of 2013, the EC issued EU wide legislation further reducing the expected free allocation for Phase III by an average of approximately 12% for the Phase III period. The final allocation for the Phase III period that we received in January is approximately 48 million allowances. Based on 2013 emission intensity levels and projected future production levels and as a result of carryover allowances from the NAP II period, we do not currently expect to need to purchase credits until 2019 and currently estimate a shortfall of 14 million allowances for the Phase III period. However, due to a number of variable factors such as the future market value of allowances, future production levels and future emission intensity levels, we cannot reliably estimate the full cost of complying with the ETS regulations at this time.
	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 GHG reductions under the CAA. 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.
	It is impossible to estimate the timing or impact of these or other future government action on U. S. Steel, although it could be significant. Such impacts may include substantial capital expenditures, costs for emission allowances, restriction of production, and higher prices for coking coal, natural gas and electricity generated by carbon based systems.
	European Union (EU) Environmental Requirements – Slovakia is currently considering a law implementing an EU Waste Framework Directive that would more strictly regulate waste disposal and increase fees for waste disposed of in landfills including privately owned landfills. The intent of the waste directive is to encourage recycling but because Slovakia has not adopted implementing legislation, we cannot estimate the full financial impact of this prospective legislation at this time.
	The EU’s Industry Emission Directive will require implementation of EU determined best available techniques (BATs) to reduce environmental impacts as well as compliance with BAT associated emission levels. This directive includes operational requirements for air emissions, wastewater discharges, solid waste disposal and energy conservation, dictates certain operating practices and imposes stricter emission limits. Producers will be required to be in compliance with the iron and steel BAT by March 8, 2016, unless specific extensions are granted by the Slovak environmental authority. We are currently evaluating the costs of complying with BAT, but our most recent broad estimate of likely capital expenditures is $200 million to $250 million over the 2014 to 2016 period. This amount has been reduced from prior estimates due to the exclusion of a project to upgrade our boilers at the power plant, which is discussed separately below, and because we now believe we can comply with certain of the BAT parameters without capital investments due to improved maintenance and operating practices. We are currently investigating the possibility of obtaining EU grants to fund a portion of these capital expenditures. We also believe there will be increased operating costs, such as increased energy and maintenance costs, but we are currently unable to reliably estimate them.
	Due to other EU legislation, we will be required to make changes to the boilers at our steam and power generation plant in order to comply with stricter air emission limits. In January of 2014, the operation of USSK's boilers was approved by the EC as part of Slovakia's Transitional National Plan (TNP) for bringing all boilers in Slovakia into BAT compliance by no later than 2020. The TNP establishes parameters for determining the date by which specific boilers are required to reach compliance with the new air standards, which has been determined to be October 2017 for our boilers. This gives us the flexibility of delaying the completion of the project to upgrade our boilers to no later than that date, although we may choose to accelerate the implementation of this project in order to qualify for supplementary support payments as part of Slovakia’s renewable energy program. This will result in a reduction in electricity costs once the project is completed. The current projected cost to reconstruct one existing boiler and build one new boiler to achieve compliance is broadly estimated at $150 million.
	Environmental and other 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 sold. These indemnifications and cost sharing agreements have related to the condition of the property, the approved use, certain representations and warranties, matters of title and environmental matters. While most of these provisions have not specifically dealt with environmental issues, there have been transactions in which U. S. Steel indemnified the buyer for non-compliance with past, current and future environmental laws related to existing conditions and there can be questions as to the applicability of more general indemnification provisions to environmental matters. Most recent indemnifications and cost sharing agreements are of a limited nature only applying to non-compliance with past and/or current laws. Some indemnifications and cost sharing agreements only run for a specified period of time after the transactions close and others run indefinitely. In addition, current owners of property formerly owned by U. S. Steel may have common law claims and contribution rights against U. S. Steel for environmental matters. 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 sold. Aside from the environmental liabilities already recorded as a result of these transactions due to specific environmental remediation activities and cases (included in the $233 million of accrued liabilities for remediation discussed above), there are no other known environmental liabilities related to these transactions.
	Guarantees – The maximum guarantees of the indebtedness of unconsolidated entities of U. S. Steel totaled $29 million (which includes the recorded liability of $22 million noted below) at December 31, 2013. If any default related to the guaranteed indebtedness occurs, U. S. Steel has access to its interest in the assets of the investees to reduce its potential losses under the guarantees.
	During the third quarter of 2013, U. S. Steel recorded a pretax charge of $22 million to net interest and other financial costs (see Note 5) to record a liability related to a guarantee of debt of an unconsolidated equity investment for which payment by U. S. Steel is probable. The $22 million is the maximum amount U. S. Steel would be obligated to pay as the guarantor and represents the fair value of the obligation at December 31, 2013.
	Antitrust Class Actions – In a series of lawsuits filed in federal court in the Northern District of Illinois beginning September 12, 2008, individual direct or indirect buyers of steel products have asserted that eight steel manufacturers, including U. S. Steel, conspired in violation of antitrust laws to restrict the domestic production of raw steel and thereby to fix, raise, maintain or stabilize the price of steel products in the United States. The cases are filed as class actions and claim damages related to steel product purchases during the time period of April 1, 2005 to December 31, 2007.  A hearing on class certification is expected during the first quarter of 2014. U. S. Steel is vigorously defending these lawsuits and does not believe that it is probable a liability regarding these matters has been incurred. We are unable to estimate a range of possible loss at this time.
	EPA Region V Federal Lawsuit – On August 1, 2012, the U.S. government, joined by the States of Illinois, Indiana and Michigan, filed a complaint in the Northern District of Indiana alleging various CAA and State air regulatory violations that were to have allegedly occurred at Gary Works, Granite City Works, and Great Lakes Works, our three integrated iron and steel facilities located in EPA Region V. The Complaint alleges that Gary Works failed to obtain the proper pre-construction permit for a routine reline of its Blast Furnace No. 4 in 1990, and that the three facilities failed to meet certain operational, maintenance, opacity, and recordkeeping requirements under the CAA and its implementing regulations. The Complaint requests relief in the form of statutory penalties for each violation and for injunctive relief. U. S. Steel believes that the claims asserted in the Complaint are not justified and are without statutory foundation. On September 21, 2012, U. S. Steel filed a motion to dismiss the U.S. government’s claims for relief regarding the 1990 reline of the Gary Blast Furnace No. 4 and filed an answer to the remaining allegations in the Complaint. On August 21, 2013, the district court issued an Opinion and Order, granting in part, and denying in part, the Motion to Dismiss. The court granted the Motion to Dismiss with respect to penalties such that the government is barred from seeking any civil penalties. However, the court denied our Motion to Dismiss with respect to injunctive relief. On September 6, 2013, U. S. Steel filed a Motion for Reconsideration to the district court with respect to its denial of the Motion to Dismiss regarding injunctive relief. On November 5, 2013, the Court heard oral arguments regarding U. S. Steel’s Motion for Reconsideration and to date, no ruling has been issued. In the interim, the parties are continuing with discovery. Fact discovery is being completed in three phases, consisting of one phase for each facility. The first phase of fact discovery, regarding Granite City Works, was completed on December 20, 2013. U. S. Steel will continue to vigorously defend against these claims. At this time, the potential outcome is not reasonably estimable.
	Randle Reef – The Canadian and Ontario governments have identified for remediation a sediment deposit, commonly referred to as Randle Reef, in Hamilton Harbor near USSC’s Hamilton Works, for which the regulatory agencies estimate expenditures with a net present value of approximately C$120 million (approximately $113 million). The national and provincial governments have each allocated C$40 million (approximately $38 million) for this project. Local sources, including industry, have also agreed to provide funding of C$40 million (approximately $38 million) for this project. USSC has committed to contribute approximately 11,000 tons of hot rolled steel and to fund C$2 million (approximately $2 million). The C$2 million (approximately $2 million) was contributed in 2013 and the steel contribution is expected to be made in 2014. As of December 31, 2013, the remaining contribution commitment is reflected on USSC's balance sheet as a current liability of approximately C$8 million (approximately $8 million).
	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 $15 million at December 31, 2013). 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 $166 million as of December 31, 2013, 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 our Receivables Purchase 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 $81 million at December 31, 2013, of which less than $1 million was classified as current, and $181 million at December 31, 2012, of which $5 million was classified as current. Restricted cash at December 31, 2013 also includes $43 million to fund certain capital projects at Gary Works, our Clairton Plant and Granite City Works. The proceeds become unrestricted as capital expenditures for these projects are made.
	Capital Commitments – At December 31, 2013, U. S. Steel’s contractual commitments to acquire property, plant and equipment totaled $151 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):
	2014	2015		2016	2017		2018	Later years	Total
	$854	$644		$411	$326		$296	$1,443	$3,974
	The majority of U. S. Steel’s unconditional purchase obligations relate to the supply of industrial gases, certain energy and utility services with terms ranging from two to 15 years. Unconditional purchase obligations also include coke and steam purchase commitments related to a coke supply agreement with Gateway Energy & Coke Company LLC (Gateway) under which Gateway is obligated to supply 90 percent to 105 percent of the expected annual capacity of the heat recovery coke plant, and U. S. Steel is obligated to purchase the coke from Gateway at the contract price. As of December 31, 2013, a maximum default payment of approximately $250 million would apply if U. S. Steel terminates the agreement.
	Total payments relating to unconditional purchase obligations were approximately $750 million in 2013, $730 million in 2012 and $740 million in 2011.

SCHEDULE_II_VALUATION_AND_QUAL

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES	'
	SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS AND RESERVES
	YEARS ENDED DECEMBER 31, 2013, 2012 AND 2011
	(Millions of Dollars)
					Additions				Deductions
	Description		Balance at		Charged to		Charged		Charged to		Charged			Balance at
			Beginning		Costs and		to Other		Costs and		to Other			End of
			of Period		Expenses		Accounts		Expenses		Accounts			Period
	Year ended December 31, 2013:
	Reserves deducted in the balance sheet from the assets to which they apply:
	Allowance for doubtful accounts		$	55	$	5	$	—	$	—	$	7		$	53
	Investments and long-term receivables reserve		3		—		7		—		—			10
	Deferred tax valuation allowance:
	State		—		—		—		—		—			—
	Foreign		1,099		—		142		142		71			1,028
	Year ended December 31, 2012:
	Reserves deducted in the balance sheet from the assets to which they apply:
	Allowance for doubtful accounts		$	64	$	—	$	—	$	1	$	8		$	55
	Investments and long-term receivables reserve		3		—		—		—		—			3
	Deferred tax valuation allowance:
	State		—		—		—		—		—			—
	Foreign		1,018		47		169		—		135		(a)	1,099
	Year ended December 31, 2011:
	Reserves deducted in the balance sheet from the assets to which they apply:
	Allowance for doubtful accounts		$	48	$	3	$	13	$	—	$	—		$	64
	Investments and long-term receivables reserve		22		—		—		—		19			3
	Deferred tax valuation allowance:
	State		5		—		—		—		5			—
	Foreign		870		48		119		—		19			1,018
	(a)	The deferred tax asset valuation allowance for U. S. Steel Serbia was removed as a result of the sale of U. S. Steel Serbia on January 31, 2012.

Nature_of_Business_and_Signifi1

Nature of Business and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Principles applied in consolidation	'
	Principles applied in consolidation
	These financial statements include the accounts of U. S. Steel and its majority-owned subsidiaries. Additionally, variable interest entities for which U. S. Steel is the primary beneficiary are included in the consolidated financial statements and their impacts are either partially or completely offset by noncontrolling interests. Intercompany accounts, transactions and profits have been eliminated in consolidation.
	Investments in entities over which U. S. Steel has significant influence are accounted for using the equity method of accounting and are carried at U. S. Steel’s share of net assets plus loans, advances and our share of earnings less distributions. Differences in the basis of the investment and the underlying net asset value of the investee, if any, are amortized into earnings over the remaining useful life of the associated assets.
	Income or loss from investees includes U. S. Steel’s share of income or loss from equity method investments, which is generally recorded a month in arrears, except for significant and unusual items which are recorded in the period of occurrence. Gains or losses from changes in ownership of unconsolidated investees are recognized in the period of change. Intercompany profits and losses on transactions with equity investees have been eliminated in consolidation, subject to lower of cost or market inventory adjustments.
	U. S. Steel evaluates impairment of its equity method investments whenever circumstances indicate that a decline in value below carrying value is other than temporary. Under these circumstances, we adjust the investment down to its estimated fair value, which then becomes its new carrying value.
	Investments in companies whose equity has no readily determinable fair value are carried at cost and are periodically reviewed for impairment.
Use of estimates	'
	Use of estimates
	Generally accepted accounting principles require management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at year-end and the reported amounts of revenues and expenses during the year. Significant items subject to such estimates and assumptions include the carrying value of property, plant and equipment; goodwill and intangible assets; valuation allowances for receivables, inventories and deferred income tax assets and liabilities; environmental liabilities; liabilities for potential tax deficiencies; potential litigation claims and settlements; and assets and obligations related to employee benefits. Actual results could differ materially from the estimates and assumptions used.
Sales recognition	'
	Sales recognition
	Sales are recognized when products are shipped, properties are sold or services are provided to customers; the sales price is fixed and determinable; collectability is reasonably assured; and title and risks of ownership have passed to the buyer. Shipping and other transportation costs charged to buyers are recorded in both sales and cost of sales.
Cash and cash equivalents	'
	Cash and cash equivalents
	Cash and cash equivalents include cash on deposit and investments in highly liquid debt instruments with maturities of three months or less.
Inventories	'
	Inventories
	Inventories are carried at the lower of cost or market. Fixed costs related to abnormal production capacity are expensed in the period incurred rather than capitalized into inventory.
	LIFO (last-in, first-out) is the predominant method of inventory costing for inventories in the United States and FIFO (first-in, first-out) is the predominant method used in Canada and Europe. The LIFO method of inventory costing was used on 59 percent and 56 percent of consolidated inventories at December 31, 2013 and 2012, respectively.
Derivative instruments	'
	Derivative instruments
	U. S. Steel uses commodity-based and foreign currency derivative instruments to manage its exposure to price and foreign currency exchange rate risk. Forward physical purchase contracts and foreign exchange forward contracts are used to reduce the effects of fluctuations in the purchase price of natural gas and certain nonferrous metals and also certain business transactions denominated in foreign currencies. U. S. Steel has not elected to designate derivative instruments as qualifying for hedge accounting treatment. As a result, the changes in fair value of these derivatives are recognized immediately in results of operations. See Note 13 for further details on U. S. Steel’s derivatives.
Goodwill and identifiable intangible assets	'
	Goodwill and identifiable intangible assets
	Goodwill represents the excess of the cost over the fair value of acquired identifiable tangible and intangible assets and liabilities assumed from businesses acquired. Goodwill is tested for impairment at the reporting unit level annually in the third quarter and whenever events or circumstances indicate that the carrying value may not be recoverable.
	U. S. Steel evaluates goodwill for impairment by either performing a qualitative evaluation or a two-step quantitative test, which involves comparing the estimated fair value of the associated reporting unit to its carrying value, including goodwill. The qualitative evaluation is an assessment of factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount, including goodwill. Factors considered as part of the qualitative assessment include entity-specific, industry, market and general economic conditions. U. S. Steel may elect to bypass this qualitative assessment for some or all of its reporting units and perform a two step quantitative test. The quantitative test involves estimating a reporting unit's fair value based upon a discounted cash flow model, using a market participant approach. U. S. Steel performed the two step quantitative test during the third quarter of 2013 and recorded an impairment charge of approximately $1.8 billion.
	U. S. Steel has determined that certain acquired intangible assets have indefinite useful lives. These assets are reviewed for impairment annually and whenever events or circumstances indicate that the carrying value may not be recoverable.
	Identifiable intangible assets with finite lives are amortized on a straight-line basis over their estimated useful lives and are reviewed for impairment whenever events or circumstances indicate that the carrying value may not be recoverable.
	See Note 11 for further details on our evaluation of goodwill and intangible asset impairment.
Property, plant and equipment	'
	Property, plant and equipment
	Property, plant and equipment is carried at cost and is depreciated on a straight-line basis over the estimated useful lives of the assets.
	Depletion of mineral properties is based on rates which are expected to amortize cost over the estimated tonnage of minerals to be removed.
	U. S. Steel evaluates impairment of its property, plant and equipment whenever circumstances indicate that the carrying value may not be recoverable. Asset impairments are recognized when the carrying value of an asset grouping exceeds its aggregate projected undiscounted cash flows.
	When property, plant and equipment depreciated on a group basis is sold or otherwise disposed of, proceeds are credited to accumulated depreciation, depletion and amortization with no immediate effect on income. When property, plant and equipment depreciated on an individual basis is sold or otherwise disposed of, any gains or losses are reflected in income. Gains on disposal of long-lived assets are recognized when earned. If a loss on disposal is expected, such losses are recognized when the assets are reclassified as assets held for sale or when impaired as part of an asset group’s impairment. During the third quarter of 2013, the requirement to move to the second step of the annual goodwill impairment analysis was considered a triggering event and U. S. Steel completed a review of its long-lived assets. This review performed during the third quarter of 2013 indicated that the assets were not impaired. There were no triggering events that required fixed assets to be evaluated for impairment in 2012. During the third and fourth quarters of 2011, we evaluated the U. S. Steel Europe (USSE) asset group’s long-lived assets for impairment because the potential disposition of U. S. Steel Serbia (USSS) was considered a triggering event. Although we recorded a loss of $399 million as a result of the sale of USSS in the first quarter of 2012 (this transaction did not meet held-for-sale criteria at December 31, 2011), the fixed asset impairment evaluations did not indicate an impairment at December 31, 2011 since we test the fixed assets at the asset group level, which was USSE at that date. USSE consisted of both U. S. Steel Košice (USSK) and USSS and the estimated fair value of the USSE asset group exceeded its carrying value and resulted in no impairment of fixed assets at the USSE asset group level at December 31, 2011.
Major maintenance activities	'
	Major maintenance activities
	U. S. Steel incurs maintenance costs on all of its major equipment. Costs that extend the life of the asset, materially add to its value, or adapt the asset to a new or different use are separately capitalized in property, plant and equipment and are depreciated over the estimated useful life. All other repair and maintenance costs are expensed as incurred.
Environmental remediation	'
	Environmental remediation
	Environmental expenditures are capitalized if the costs mitigate or prevent future contamination or if the costs improve existing assets’ environmental safety or efficiency. U. S. Steel provides for remediation costs and penalties when the responsibility to remediate is probable and the amount of associated costs is reasonably estimable. The timing of remediation accruals typically coincides with completion of studies defining the scope of work to be undertaken or the commitment to a formal plan of action. Remediation liabilities are accrued based on estimates of believed environmental exposure and are discounted if the amount and timing of the cash disbursements are readily determinable.
Asset retirement obligations	'
	Asset retirement obligations
	Asset retirement obligations (AROs) are initially recorded at fair value and are capitalized as part of the cost of the related long-lived asset and depreciated in accordance with U. S. Steel’s depreciation policies for property, plant and equipment. The fair value of the obligation is determined as the discounted value of expected future cash flows. Accretion expense is recorded each month to increase this discounted obligation over time. Certain AROs related to disposal costs of the majority of assets at our integrated steel facilities are not recorded because they have an indeterminate settlement date. These AROs will be initially recognized in the period in which sufficient information exists to estimate their fair value.
Pensions, other postretirement and postemployment benefits	'
	Pensions, other postretirement and postemployment benefits
	U. S. Steel has defined contribution or multi-employer arrangements for pension benefits for more than half of its North American employees and non-contributory defined benefit pension plans covering the remaining North American employees. U. S. Steel has defined benefit retiree health care and life insurance plans (Other Benefits) that cover the majority of its employees in North America upon their retirement. Non-union salaried employees in the United States hired on or after July 1, 2003 participate in a defined contribution plan. In addition, most domestic salaried employees participate in defined contribution plans (401(k) plans). The Steelworkers Pension Trust (SPT), a multi-employer pension plan, to which U. S. Steel contributes on the basis of a fixed dollar amount for each hour worked by participating employees, currently covers approximately 60 percent of our union employees in the United States. Government-sponsored programs into which U. S. Steel makes required contributions cover the majority of U. S. Steel’s European employees. In Canada, the majority of employees of USSC participate in defined benefit pension plans and retiree health and life insurance plans. Union employees hired after October 15, 2011 at the Hamilton Plant and after April 16, 2010 at the Lake Erie Plant are covered by defined contribution arrangements. Non-union salaried employees in Canada hired after 1997 participate in defined contribution arrangements.
	The net pension and Other Benefits obligations and the related periodic costs are based on, among other things, assumptions of the discount rate, estimated return on plan assets, salary increases, the mortality of participants and the current level and future escalation of health care costs. Additionally, U. S. Steel recognizes an obligation to provide postemployment benefits for disability-related claims covering indemnity and medical payments for certain employees in North America. The obligation for these claims and the related periodic costs are measured using actuarial techniques and assumptions. Actuarial gains and losses occur when actual experience differs from any of the many assumptions used to value the benefit plans, or when assumptions change. The Company recognizes into income on an annual basis any unrecognized actuarial net gains or losses that exceed 10 percent of the larger of the projected benefit obligation or plan assets (the corridor), amortized over the plan participants' average life expectancy or average future service, depending on the demographics of the plan.
Concentration of credit and business risks	'
	Concentration of credit and business risks
	U. S. Steel is exposed to credit risk in the event of nonpayment by customers, principally within the automotive, container, construction, steel service center, appliance and electrical, conversion, and oil, gas and petrochemical industries. Changes in these industries may significantly affect U. S. Steel’s financial performance and management’s estimates. U. S. Steel mitigates its exposure to credit risk by performing ongoing credit evaluations and, when deemed necessary, requiring letters of credit, credit insurance, prepayments, guarantees or other collateral.
	The majority of U. S. Steel’s customers are located in North America and Europe. No single customer accounted for more than 10 percent of gross annual revenues.
Foreign currency translation	'
	Foreign currency translation
	U. S. Steel is subject to the risk of the effects of exchange rates on revenues and operating costs and existing assets or liabilities denominated in currencies other than our reporting currency, the U.S. dollar.
	The functional currency for U. S. Steel Europe (USSE) is the euro (€). U. S. Steel Canada Inc.’s (USSC) functional currency is the Canadian dollar (C$). Assets and liabilities of these entities are translated into U.S. dollars at period-end exchange rates. Revenue and expenses are translated using the average exchange rate for the reporting period. Resulting translation adjustments are recorded in the accumulated other comprehensive income (loss) component of stockholders’ equity. Gains and losses from foreign currency transactions are included in net income (loss) for the period.
Stock-based compensation	'
	Stock-based compensation
	U. S. Steel accounts for its various stock-based employee compensation plans in accordance with the guidance in Accounting Standards Codification (ASC) Topic 718 on stock compensation (see Note 12).
Deferred taxes	'
	Deferred taxes
	Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. The realization of deferred tax assets is assessed quarterly based on several interrelated factors. These factors include U. S. Steel’s expectation to generate sufficient future taxable income and the projected time period over which these deferred tax assets will be realized. U. S. Steel records a valuation allowance when necessary to reduce deferred tax assets to the amount that will more likely than not be realized. Deferred tax liabilities have not been recognized for the undistributed earnings of certain foreign subsidiaries because management intends to indefinitely reinvest such earnings in foreign operations. See Note 8 for further details of deferred taxes.
Insurance	'
	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 automobile 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.
Sales taxes	'
	Sales taxes
	Sales are recorded net of sales taxes charged to customers. Sales taxes primarily relate to value-added tax on sales.
Reclassifications and out of period adjustments	'
	Reclassifications and out of period adjustments
	Certain reclassifications of prior years’ data have been made to conform to the current year presentation.
	In 2013, the Company revised its classification of certain deferred tax assets as of December 31, 2012. The revision resulted in a $122 million increase to current deferred tax assets with a corresponding decrease to non-current deferred tax assets. The revision, which the Company determined is not material to its consolidated financial position, had no impact on the Consolidated Statement of Operations, Statement of Comprehensive Income/(Loss) or Statement of Cash Flows.
	In 2013, the Company recorded two out of period adjustments to correct the presentation of deferred taxes. The adjustments recorded were a tax benefit of approximately $13 million and a tax charge of approximately $19 million for deferred taxes related to fixed assets for prior years' differences between the financial statement carrying amounts of assets and liabilities and their tax basis for U.S. federal and state income tax purposes. Management has determined the impact of these out of period adjustments was not material to any prior period or the year ended December 31, 2013 and as a result, recorded the adjustments in the 2013 results.
	In 2011, the Company recorded an out of period adjustment related to its enterprise resource planning project to recorded fixed assets with a corresponding increase to net income of approximately $10 million. Management has determined that the impact of the out of period adjustment was not material to any prior period or the year ended December 31, 2011, and as a result, recorded the adjustment in the 2011 results.

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Results of Segment Operations	'
	The results of segment operations are as follows:
	(In millions)		Customer				Intersegment				Net			Income			Income			Depreciation,		Capital
			Sales				Sales				Sales			(loss)			(loss)			depletion &		expenditures
														from			from			amortization
														investees			operations
	2013
	Flat-rolled		$	11,572			$	1,258			$	12,830		$	69		$	105		$	512	$	349
	USSE		2,941				3				2,944			—			28			95		40
	Tubular		2,772				5				2,777			(25		)	190			62		69
	Total reportable segments		17,285				1,266				18,551			44			323			669		458
	Other Businesses		139				134				273			(4		)	77			15		19
	Reconciling Items and Eliminations		—				(1,400		)		(1,400		)	—			(2,300		)	—		—
	Total		$	17,424			$	—			$	17,424		$	40		$	(1,900	)	$	684	$	477
	2012
	Flat-rolled		$	12,908			$	1,647			$	14,555		$	152		$	400		$	491	$	625
	USSE		2,949				145				3,094			—			34			102		38
	Tubular		3,283				8				3,291			(6		)	366			58		42
	Total reportable segments		19,140				1,800				20,940			146			800			651		705
	Other Businesses		188				139				327			(2		)	55			10		18
	Reconciling Items and Eliminations		—				(1,939		)		(1,939		)	—			(608		)	—		—
	Total		$	19,328			$	—			$	19,328		$	144		$	247		$	661	$	723
	2011
	Flat-rolled		$	12,367			$	1,360			$	13,727		$	98		$	469		$	485	$	616
	USSE		4,306				69				4,375			1			(162		)	140		109
	Tubular		3,034				7				3,041			(14		)	316			44		104
	Total reportable segments		19,707				1,436				21,143			85			623			669		829
	Other Businesses		177				345				522			—			46			12		19
	Reconciling Items and Eliminations		—				(1,781		)		(1,781		)	—			(404		)	—		—
	Total		$	19,884			$	—			$	19,884		$	85		$	265		$	681	$	848
Schedule of Reconciling Items to Income (Loss) from Operations	'
	The following is a schedule of reconciling items to income (loss) from operations:
	(In millions)		2013				2012				2011
	Items not allocated to segments:
	Postretirement benefit expense(a)		$	(221	)		$	(297	)		$	(386	)
	Other items not allocated to segments:
	Impairment of goodwill (Note11)		(1,806		)		$	—			$	—
	Restructuring and other charges (Note 23)		(248		)		—				—
	Environmental remediation charge		(32		)		—				(18		)
	Write-off of equity investment (Note 9)		(16		)		—				—
	Supplier contract dispute settlement		23				15				—
	Net loss on the sale of assets (Note 4)		—				(310		)		—
	Labor agreement lump sum payments (Note 15)		—				(35		)		—
	Property tax settlements		—				19				—
	Total other items not allocated to segments		(2,079		)		(311		)		(18		)
	Total reconciling items		$	(2,300	)		$	(608	)		$	(404	)
	(a)	Consists of the net periodic benefit cost elements, other than service cost and amortization of prior service cost for active employees, associated with our pension, retiree health care and life insurance benefit plans.
Net Sales by Product	'
	The following summarizes net sales by product:
	(In millions)		2013				2012				2011
	Flat-rolled		$	13,508			$	14,721			$	15,861
	Tubular		2,826				3,246				2,986
	Other(a)		1,090				1,361				1,037
	Total		$	17,424			$	19,328			$	19,884
	(a)	Primarily includes sales of steel production by-products, railroad services and real estate operations.
Net Sales, Property, Plant and Equipment and Equity Method Investments Based on Location of Operating Segment	'
	The information below summarizes net sales, property, plant and equipment and equity method investments based on the location of the operating segment to which they relate.
	(In millions)		Year		Net				Assets
					Sales
	North America		2013		$	14,484			$	5,425		(a)
			2012		$	16,379			$	5,907		(a)
			2011		$	15,578			$	5,869		(a)
	Europe		2013		2,940				1,022			(b)
			2012		2,949				1,034			(b)
			2011		4,306				1,321			(b)
	Other Foreign Countries		2013		—				33
			2012		—				37
			2011		—				40
	Total		2013		$	17,424			$	6,480
			2012		$	19,328			$	6,978
			2011		$	19,884			$	7,230
	(a)	Assets with a book value of $4,443 million, $4,523 million and $4,424 million were located in the United States at December 31, 2013, 2012 and 2011, respectively.
	(b)	Assets with a book value of $1,022 million, $1,034 million and $1,064 million were located in Slovakia at December 31, 2013, 2012 and 2011, respectively.

Net_Interest_and_Other_Financi1

Net Interest and Other Financial Costs (Tables)	12 Months Ended
	Dec. 31, 2013
Other Income and Expenses [Abstract]	'
Net Interest and Other Financial Costs	'
	(In millions)		2013			2012			2011
	Interest income:
	Interest income		$	(3	)	$	(7	)	$	(6	)
	Interest expense and other financial costs:
	Interest incurred(a)		285			255			229
	Less interest capitalized		19			41			39
	Total interest expense		266			214			190
	Foreign currency net loss (b)		11			7			27
	Financial costs on:
	Sale of receivables		3			4			4
	Amended Credit Agreement		4			4			5
	USSK credit facilities		3			3			2
	Other (c)		28			—			—
	Amortization of discounts and deferred financing costs		20			16			16
	Total other financial costs		69			34			54
	Net interest and other financial costs		$	332		$	241		$	238
	(a)	Includes a pretax charge of $34 million during 2013 related to premiums on the repurchase of $542 million of our 4.00% Senior Convertible Notes.
	(b)	The functional currency for USSE is the euro and the functional currency for USSC is the Canadian dollar. Foreign currency net loss is a result of transactions denominated in currencies other than the euro or Canadian dollar. Additionally, foreign currency net loss includes the impacts of the remeasurement of a U.S. dollar-denominated intercompany loan to a European subsidiary and the impacts of euro-U.S. dollar derivatives activity. Effective January 1, 2012, the functional currency of the European entity was changed from the euro to the U.S. dollar because of significant changes in economic facts and circumstances, including the sale of U. S. Steel Serbia. The change in functional currency has been applied on a prospective basis since January 1, 2012.
	(c)	Consists primarily of a charge of $22 million in 2013 related to a guarantee of an unconsolidated equity investment for which payment by U. S. Steel is probable (see Note 24).

Income_and_Dividends_Per_Commo1

Income and Dividends Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Computations for Basic and Diluted Earnings Per Common Share from Continuing Operations	'
	(Dollars in millions, except per share amounts)	2013				2012			2011
	Net loss attributable to United States Steel Corporation shareholders	$	(1,672	)		$	(124	)	$	(53	)
	Plus income effect of assumed conversion-interest on convertible notes	—				—			—
	Net loss after assumed conversion	$	(1,672	)		$	(124	)	$	(53	)
	Weighted-average shares outstanding (in thousands):
	Basic	144,578				144,237			143,967
	Effect of convertible notes	—				—			—
	Effect of stock options, restricted stock units and performance awards	—				—			—
	Adjusted weighted-average shares outstanding, diluted	144,578				144,237			143,967
	Basic loss per common share	$	(11.56	)		(0.86		)	(0.37		)
	Diluted loss per common share	$	(11.56	)		(0.86		)	(0.37		)
Antidilutive Securities that were Not Included in Computations of Diluted Loss Per Common Share	'
	The following table summarizes the securities that were antidilutive, and therefore, were not included in the computation of diluted loss per common share:
	(In thousands)	2013			2012			2011
	Securities granted under the 2005 Stock Incentive Plan	7,039			5,581			3,912
	Securities convertible under the Senior Convertible Notes	14,017		(a)	27,059			27,059
	Total	21,056			32,640			30,971
	(a) On March 27, 2013, we repurchased approximately $542 million aggregate principal amount of our 4% Senior Convertible Notes due in 2014. If the repurchases had occurred on January 1, 2013, the antidilutive securities would have been 10,058 thousand for the year ended December 31, 2013.

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2013
Inventory Disclosure [Abstract]	'
Inventories	'
	(In millions)	December 31, 2013		December 31, 2012
	Raw materials	$	1,011	$	945
	Semi-finished products	1,023		883
	Finished products	558		573
	Supplies and sundry items	96		102
	Total	$	2,688	$	2,503

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Provisions (Benefits) for Income Taxes	'
	Provisions (benefits) for income taxes
		2013									2012								2011
	(In millions)	Current			Deferred			Total			Current		Deferred			Total			Current			Deferred			Total
	Federal	$	(210	)	$	(167	)	$	(377	)	$	48	$	61		$	109		$	148		$	(92	)	$	56
	State and local	8			(50		)	(42		)	5		23			28			(2		)	15			13
	Foreign	1			(142		)	(141		)	4		(10		)	(6		)	2			9			11
	Total	$	(201	)	$	(359	)	$	(560	)	$	57	$	74		$	131		$	148		$	(68	)	$	80
Reconciliation of Federal Statutory Tax to Total Provisions	'
	A reconciliation of the federal statutory tax rate of 35 percent to total provisions follows:
	(In millions)	2013			2012			2011
	Statutory rate applied to income (loss) before income taxes	$	(781	)	$	2		$	9
	Effects of foreign operations	467			266			184
	Worthless stock loss and bad debt deduction	(417		)	—			—
	Goodwill impairment	410			—			—
	Tax accounting benefit related to increase in OCI	(142		)	—			—
	Excess percentage depletion	(94		)	(107		)	(102		)
	State and local income taxes after federal income tax effects	(27		)	18			8
	Adjustments of prior years’ federal income taxes	9			(46		)	(11		)
	Tax credits	(3		)	—			(3		)
	Deduction for domestic production activities	12			(7		)	(8		)
	Medicare Part D drug program subsidies	—			(1		)	(6		)
	Other	6			6			9
	Total (benefit) provision	$	(560	)	$	131		$	80
Reconciliation of Unrecognized Tax Benefits	'
	A tabular reconciliation of unrecognized tax benefits follows:
	(In millions)	2013			2012			2011
	Unrecognized tax benefits, beginning of year	$	85		$	110		$	115
	Increases – tax positions taken in prior years	1			3			1
	Decreases – tax positions taken in prior years	(6		)	(25		)	(4		)
	Increases – current tax positions	70			2			3
	Settlements	—			(5		)	—
	Lapse of statute of limitations	(23		)	—			(5		)
	Unrecognized tax benefits, end of year	$	127		$	85		$	110
Deferred Tax Assets and Liabilities	'
	Deferred tax assets and liabilities resulted from the following:
		December 31,
	(In millions)	2013			2012
	Deferred tax assets:
	Federal tax loss carryforwards (expiring in 2033)	$	386		$	—
	State tax credit carryforwards (expiring in 2027)	7			2
	State tax loss carryforwards (expiring in 2015 through 2033)	37			35
	Minimum tax credit carryforwards	108			157
	General business credit carryforwards	69			66
	Foreign tax loss and credit carryforwards (expiring in 2014 through 2033)	713			637
	Employee benefits	908			1,704
	Receivables, payables and debt	88			89
	Expected federal benefit for deducting state deferred income taxes	32			51
	Inventory	107			—
	Contingencies and accrued liabilities	119			133
	Valuation allowances:
	Foreign	(1,028		)	(1,099		)
	Total deferred tax assets	1,546			1,775
	Deferred tax liabilities:
	Property, plant and equipment	1,205			1,041
	Investments in subsidiaries and equity investees	50			97
	Inventory	—			1
	Future reduction of foreign tax credits	49			—
	Other temporary differences	95			41
	Total deferred tax liabilities	1,399			1,180
	Net deferred tax asset	$	147		$	595

Investments_and_LongTerm_Recei1

Investments and Long-Term Receivables (Tables)	12 Months Ended
	Dec. 31, 2013
Equity Method Investments and Joint Ventures [Abstract]	'
Investments and Long-Term Receivables	'
			December 31,
	(In millions)		2013		2012
	Equity method investments		$	558	$	570
	Receivables due after one year, less allowance of $3 for both periods		58		34
	Other		5		5
	Total		$	621	$	609
Summarized Financial Information of Investees Accounted for by Equity Method of Accounting	'
	Summarized financial information of all investees accounted for by the equity method of accounting is as follows (amounts represent 100% of investee financial information):
	(In millions)		2013		2012		2011
	Income data – year ended December 31:
	Net Sales		$	3,735	$	4,019	$	3,514
	Operating income		449		650		319
	Net income		413		602		264
	Balance sheet date – December 31:
	Current Assets		$	912	$	1,028
	Noncurrent Assets		1,876		1,981
	Current liabilities		677		569
	Noncurrent Liabilities		852		1,220
Investees Accounted for using Equity Method	'
	Investees accounted for using the equity method include:
	Investee	Country	December 31, 2013
			Interest
	Acero Prime, S. R. L. de CV	Mexico	40	%
	Apolo Tubulars S.A.	Brazil	50	%
	Baycoat Limited Partnership	Canada	50	%
	Baycoat Limited	Canada	50	%
	Chrome Deposit Corporation	United States	50	%
	Daniel Ross Bridge, LLC	United States	50	%
	D.C. Chrome Limited	Canada	50	%
	Double Eagle Steel Coating Company	United States	50	%
	Double G Coatings Company L.P.	United States	50	%
	Feralloy Processing Company	United States	49	%
	Hibbing Development Company	United States	24.1	%
	Hibbing Taconite Company(a)	United States	14.7	%
	Leeds Retail Center, LLC	United States	38	%
	Patriot Premium Threading Services	United States	50	%
	PRO-TEC Coating Company	United States	50	%
	Strategic Investment Fund Partners I(b)	United States	8.6	%
	Strategic Investment Fund Partners II(b)	United States	4.9	%
	Swan Point Development Company, Inc.	United States	50	%
	Tilden Mining Company, L.C.(a)	United States	15	%
	United Spiral Pipe, LLC	United States	35	%
	USS-POSCO Industries	United States	50	%
	Worthington Specialty Processing	United States	49	%
	(a)	Hibbing Taconite Company (HTC) is an unincorporated joint venture that is owned, in part, by Hibbing Development Company (HDC), which is accounted for using the equity method. Through HDC we are able to influence the activities of HTC, and as such, its activities are accounted for using the equity method.
	Tilden Mining Company, L.C. is a limited liability company and in accordance with ASC Topic 323 “Partnerships and Unincorporated Joint Ventures,” (ASC Topic 323) its financial activities are accounted for using the equity method.
	(b)	Strategic Investment Fund Partners I and II are limited partnerships and in accordance with ASC Topic 323, the financial activities are accounted for using the equity method.

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Property, Plant and Equipment	'
			December 31,
	(In millions)	Useful Lives	2013		2012
	Land and depletable property	—	$	251	$	264
	Buildings	35 years	1,367		1,394
	Machinery and equipment	4-22 years	14,386		14,408
	Information technology	5-6 years	758		709
	Assets under capital lease	2-25 years	37		131
	Total		16,799		16,906
	Less accumulated depreciation and depletion		10,877		10,498
	Net		$	5,922	$	6,408

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Changes in Carrying Amount of Goodwill by Segment	'
	The changes in the carrying amount of goodwill by segment for the years ended December 31, 2013 and December 31, 2012 are as follows:
		Flat-rolled				USSE				Tubular				Total
		Segment				Segment				Segment
	Balance at January 1, 2012	$	945			$	4			$	834			$	1,783
	Currency translation	39				—				—				39
	Balance at December 31, 2012	$	984			$	4			$	834			$	1,822
	Goodwill from acquisitions	—				—				3				3
	Impairment	(969		)		—				(837		)		(1,806		)
	Currency translation	(15		)		—				—				(15		)
	Balance at December 31, 2013	$	—			$	4			$	—			$	4
Amortizable Intangible Assets	'
	Amortizable intangible assets are amortized on a straight-line basis over their estimated useful lives and are detailed below:
				As of December 31, 2013												As of December 31, 2012
	(In millions)	Useful		Gross				Accumulated				Net				Gross		Accumulated		Net
		Lives		Carrying				Amortization				Amount				Carrying		Amortization		Amount
				Amount												Amount
	Customer relationships	22-23 Years		$	215			$	63			$	152			$	221	$	54	$	167
	Other	2-20 Years		23				12				11				22		11		11
	Total amortizable intangible assets			$	238			$	75			$	163			$	243	$	65	$	178

StockBased_Compensation_Plans_

Stock-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Total Stock-Based Compensation Awards Granted	'
	The following table summarizes the total stock-based compensation awards granted during the years 2013, 2012 and 2011:
			Executive Stock			Non-executive Stock			Restricted			Performance
			Options			Options			Stock			Awards
									Units
	2013 Grants		838,610			971,860			1,043,420			271,960
	2012 Grants		510,570			993,310			910,011			328,780
	2011 Grants		228,300			478,760			422,080			85,040
Total Compensation Expense Recognized for Stock-Based Compensation Awards	'
	The following table summarizes the total compensation expense recognized for stock-based compensation awards:
	(In millions, except per share amounts)		12/31/13				12/31/12				12/31/11
	Stock-based compensation expense recognized:
	Cost of sales		$	10			$	12			$	10
	Selling, general and administrative expenses		23				26				23
	Total		33				38				33
	Related deferred income tax benefit		12				14				12
	Decrease in net income		$	21			$	24			$	21
	Decrease in basic earnings per share		0.14				0.16				0.14
	Decrease in diluted earnings per share		0.14				0.16				0.14
Black-Scholes Assumptions	'
	Compensation expense for stock options is recorded over the vesting period based on the fair value on the date of grant, as calculated by U. S. Steel using the Black-Scholes model and the assumptions listed below. The 2013, 2012 and 2011 awards vest ratably over a three-year service period and have a term of ten years. Stock options are generally issued at the market price of the underlying stock on the date of the grant. The 2013 executive grants, however, were issued at the greater of (1) the premium exercise price of $25 or (2) the market price on the grant date. Upon exercise of stock options, shares of U. S. Steel stock are issued from treasury stock.
	Black-Scholes Assumptions (a)		2013 Executive Grants				2013 Non-Executive Grants				2012 Grants			2011 Grants
	Grant date price per share of option award		$	18.62			$	18.64			$	22.28		$	45.81
	Exercise price per share of option award		$	25.03			$	18.64			$	22.28		$	45.81
	Expected annual dividends per share		$	0.2			$	0.2			$	0.2		$	0.2
	Expected life in years		5				5				5			5
	Expected volatility		66		%		67		%		68		%	64		%
	Risk-free interest rate		1.3		%		1		%		0.8		%	1.8		%
	Average grant date fair value per share of unvested option awards as calculated from above		$	8.44			$	9.7			$	11.93		$	24.39
	(a)The assumptions represent a weighted-average for all grants during the year.
Status and Activity of Stock Options	'
	The following table shows a summary of the status and activity of stock options for the year ended December 31, 2013:
			Shares			Weighted-				Weighted-		Aggregate
						Average				Average		Intrinsic
						Exercise Price				Remaining		Value
						(per share)				Contractual Term		(in millions)
										(in years)
	Outstanding at January 1, 2013		4,318,966			$	43.86
	Granted		1,810,470			$	21.6
	Exercised		(14,383	)		$	22.31
	Forfeited or expired		(907,765	)		$	35.36
	Outstanding at December 31, 2013		5,207,288			$	37.66			7.5		$	21
	Exercisable at December 31, 2013		2,634,676			$	51.34			6		3
	Exercisable and expected to vest at December 31, 2013		4,946,640			$	38.42			7.4		$	20
Performance Awards Outstanding and their Fair Market Value on Respective Grant Date	'
	The following table shows a summary of the performance awards outstanding as of December 31, 2013, and their fair market value on the respective grant date:
	Performance Period		Fair Value				Minimum			Target			Maximum
			(in millions)				Shares			Shares			Shares
	2013 - 2016		$	6			—			271,960			543,920
	2012 - 2015		$	8			—			328,780			657,560
	2011 - 2014		$	6			—			85,040			170,080
Status and Activity of Nonvested Stock Awards	'
	The following table shows a summary of the status and activity of nonvested stock awards for the year ended December 31, 2013:
			Restricted			Performance			Total			Weighted-
			Stock Units			Awards (a)						Average
												Grant-Date
												Fair Value
	Nonvested at January 1, 2013		1,262,198			503,114			1,765,312			$	31.62
	Granted		1,043,420			271,960			1,315,380			19.2
	Vested		(530,827	)		—			(530,827	)		32.58
	Performance adjustment factor (b)		—			(89,294	)		(89,294	)		57.02
	Forfeited or expired		(282,533	)		(185,804	)		(468,337	)		23.34
	Nonvested at December 31, 2013		1,492,258			499,976			1,992,234			$	23.97
	(a)The number of shares shown for the performance awards is based on the target number of share awards.
	(b)	Consists of adjustments to vested performance awards to reflect actual performance. The adjustments were required since the original grants of the awards were at 100 percent of the targeted amounts.
Restricted Stock Units and Performance Awards Granted	'
	The following table presents information on RSUs and performance awards granted:
			2013				2012				2011
	Number of awards granted		1,315,380				1,238,791				507,120
	Weighted-average grant-date fair value per share		$	19.2			$	23.07			$	49.1

Derivative_Instruments_Tables

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Location and Amounts of Fair Values Related to Derivatives in Financial Statements	'
	The following summarizes the location and amounts of the fair values related to derivatives included in U. S. Steel’s financial statements as of December 31, 2013 and 2012:
			Fair Value
	(In millions)	Balance Sheet	31-Dec-13			31-Dec-12
		Location
	Foreign exchange forward contracts	Accounts payable	$	11		$	12
Location and Amounts of Gains or Losses Related to Derivatives in Financial Statements	'
	The following summarizes the location and amounts of the gains and losses related to derivatives included in U. S. Steel’s financial statements for the years ended December 31, 2013, 2012 and 2011:
		Statement of	Amount of Gain
		Operations	(Loss)
	(In millions)	Location	Year Ended December 31, 2013			Year Ended December 31, 2012			Year Ended December 31, 2011
	Foreign exchange forward contracts	Other financial costs	$	(14	)	$	(7	)	$	13

Debt_Tables

Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Debt Instrument [Line Items]	'
Schedule of Debt	'
							December 31,
	(In millions)		Interest		Maturity		2013				2012
			Rates %
	2037 Senior Notes		6.65		2037		$	350			$	350
	2022 Senior Notes		7.5		2022		400				400
	2021 Senior Notes		6.875		2021		275				—
	2020 Senior Notes		7.375		2020		600				600
	2018 Senior Notes		7		2018		500				500
	2017 Senior Notes		6.05		2017		450				450
	2019 Senior Convertible Notes		2.75		2019		316				—
	2014 Senior Convertible Notes		4		2014		322				863
	Province Note (C$150 million)		1		2015		141				151
	Environmental Revenue Bonds		5.38 - 6.88		2015 - 2042		549				549
	Recovery Zone Facility Bonds		6.75		2040		70				70
	Fairfield Caster Lease				2022		35				35
	Other capital leases and all other obligations				2014 - 2020		—				1
	Amended Credit Agreement		Variable		2016		—				—
	USSK Revolver		Variable		2016		—				—
	USSK credit facilities		Variable		2015 - 2016		—				—
	Total Debt						4,008				3,969
	Less Province Note fair value adjustment						15				23
	Less unamortized discount						54				8
	Less short-term debt and long-term debt due within one year						323				2
	Long-term debt						$	3,616			$	3,936
Trade Receivables for U.S. Steel Receivables, LLC	'
	The table below summarizes the trade receivables at December 31, 2013 and 2012, for USSR:
	(In millions)		2013				2012
	Balance of accounts receivable-net, eligible for sale to third-parties		$	988			$	1,127
	Accounts receivable sold to third-parties		—				—
	Balance included in Receivables on the balance sheet of U. S. Steel		$	988			$	1,127
Aggregate Maturities of Debt	'
	Debt Maturities – Aggregate maturities of debt are as follows (in millions):
	2014				2015				2016				2017		2018		Later		Total
																	Years
	$	323			$	189			$	45			$	500	$	503	$	2,433	$	3,993	(a)
	(a)Debt maturities include the Province Note fair value adjustment discussed above.
2021 Senior Notes	'
Debt Instrument [Line Items]	'
Redemption Price of Senior Notes as Percentage of Principal Amount Plus Accrued and Unpaid Interest to, but Excluding, Redemption Date	'
	U. S. Steel may redeem the 2021 Senior Notes, in whole or in part, at our option at any time and from time to time on or after April 1, 2017 at the redemption price for such notes set forth below 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 April 1 of the years indicated below:
	Year	Redemption Price
	2017	103.438	%
	2018	101.719	%
	2019 and thereafter	100	%
2022 Senior Notes	'
Debt Instrument [Line Items]	'
Redemption Price of Senior Notes as Percentage of Principal Amount Plus Accrued and Unpaid Interest to, but Excluding, Redemption Date	'
	U. S. Steel may redeem the 2022 Senior Notes, in whole or in part, at our option at any time or from time to time on or after March 15, 2017 at the redemption price for such notes set forth below 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 March 15 of the years indicated below:
	Year	Redemption Price
	2017	103.75	%
	2018	102.5	%
	2019	101.25	%
	2020 and thereafter	100	%

Pensions_and_Other_Benefits_Ta

Pensions and Other Benefits (Tables)	12 Months Ended
	Dec. 31, 2013																									Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'																									'
Details Relating to Pension Benefits and Other Benefits	'																									'
	Details relating to Pension Benefits and Other Benefits are below.
			Pension Benefits								Other Benefits
	(In millions)		2013				2012				2013			2012
	Change in benefit obligations
	Benefit obligations at January 1		$	11,347			$	10,770			$	3,940		$	4,186
	Service cost		128				118				27			28
	Interest cost		403				467				141			170
	Plan amendments		—				29				—			(522		)
	Actuarial losses (gains)		(421		)		848				(420		)	375
	Exchange rate loss (gain)		(234		)		81				(55		)	19
	Settlements, curtailments and termination benefits		(16		)		(28		)		—			—
	Benefits paid		(950		)		(938		)		(255		)	(316		)
	Benefit obligations at December 31		$	10,257			$	11,347			$	3,378		$	3,940
	Change in plan assets
	Fair value of plan at January 1		$	8,659			$	8,353			$	1,732		$	1,473
	Actual return on plan assets		1,363				945				346			196
	Employer contributions		226				234				10			76
	Exchange rate gain (loss)		(187		)		56				—			—
	Benefits paid from plan assets		(939		)		(929		)		(118		)	(13		)
	Fair value of plan assets at December 31		$	9,122			$	8,659			$	1,970		$	1,732
	Funded status of plans at December 31		$	(1,135	)		$	(2,688	)		$	(1,408	)	$	(2,208	)
Amounts Recognized in Accumulated Other Comprehensive Loss	'																									'
	Amounts recognized in accumulated other comprehensive loss:
							2013
	(In millions)		12/31/12				Amortization				Activity			12/31/13
	Pensions
	Prior Service Cost		$	99			$	(24	)		$	1		$	76
	Actuarial losses		4,656				(367		)		(1,165		)	3,124
	Other Benefits
	Prior Service Cost		(180		)		13				—			(167		)
	Actuarial Losses		613				(31		)		(632		)	(50		)
					Amount reclassified
					from AOCI
	(In millions) (a)		Details about AOCI components		2013				2012
			Amortization of pension and other benefit items
			Prior service costs		$	(11	)		$	(33	)	(b)
			Actuarial gains/(losses)		(398		)		(360		)	(b)
			Total before tax		(409		)		(393		)
			Tax benefit		143				130
			Net of tax		$	(266	)		$	(263	)
	(a)Amounts in parentheses indicate debits to income/loss.
	(b)	These AOCI components are included in the computation of net periodic benefit cost (see Note 16 for additional details).
Pension and Other Benefits Recognized in Balance Sheet	'																									'
	As of December 31, 2013 and 2012, the following amounts were recognized in the balance sheet:
			Pension Benefits								Other Benefits
	(In millions)		2013				2012				2013			2012
	Noncurrent assets		$	23			$	11			$	—		$	—
	Current liabilities		(298		)		(245		)		(337		)	(360		)
	Noncurrent liabilities		(860		)		(2,454		)		(1,071		)	(1,848		)
	Accumulated other comprehensive loss (a)		3,200				4,755				(217		)	433
	Net amount recognized		$	2,065			$	2,067			$	(1,625	)	$	(1,775	)
	(a)	Accumulated other comprehensive loss effects associated with accounting for pensions and other benefits in accordance with ASC Topic 715 at December 31, 2013 and December 31, 2012, respectively, are reflected net of tax of $886 million and $1,568 million respectively, on the Statement of Stockholders’ Equity.
Information for Pension Plans with Accumulated Benefit Obligation in Excess of Plan Assets	'																									'
	The Accumulated Benefit Obligation (ABO) for all defined benefit pension plans was $9,798 million and $10,817 million at December 31, 2013 and 2012, respectively.
			December 31,
	(In millions)		2013				2012
	Information for pension plans with an accumulated benefit obligation in excess of plan assets:
	Aggregate accumulated benefit obligations (ABO)		$	(9,685	)		$	(10,782	)
	Aggregate projected benefit obligations (PBO)		(10,144		)		(11,313		)
	Aggregate fair value of plan assets		8,986				8,614
Details of Net Periodic Benefit Costs Related to Pension and Other Benefits	'																									'
	Following are the details of net periodic benefit costs related to Pension and Other Benefits:
			Pension Benefits											Other Benefits
	(In millions)		2013				2012				2011			2013				2012				2011
	Components of net periodic benefit cost:
	Service cost		$	128			$	118			$	111		$	27			$	28			$	25
	Interest cost		403				467				511			141				170				209
	Expected return on plan assets		(611		)		(614		)		(623		)	(131		)		(117		)		(105		)
	Amortization - prior service costs		24				22				21			(13		)		11				25
	- actuarial losses		367				352				352			31				8				5
	Net periodic benefit cost, excluding below		311				345				372			55				100				159
	Multiemployer plans (a)		74				70				65			—				—				—
	Settlement, termination and curtailment (gains)/losses		11				(3		)		6			—				—				—
	Net periodic benefit cost		$	396			$	412			$	443		$	55			$	100			$	159
	(a)	Primarily represents pension expense for the SPT covering USW employees hired from National Steel Corporation and new USW employees hired after May 21, 2003.
Amounts in Accumulated Other Comprehensive Income that are Expected to be Recognized as Components of Net Periodic Benefit Cost	'																									'
	The amounts in accumulated other comprehensive income that are expected to be recognized as components of net periodic benefit cost during 2014 are as follows:
	(In millions)		Pension				Other
			Benefits				Benefits
			2014				2014
	Amortization of actuarial loss/(gain)		$	282			$	(13	)
	Amortization of prior service cost		22				(3		)
	Total recognized from accumulated other comprehensive income		$	304			$	(16	)
Assumptions used to Determine Benefit Obligation and Net Periodic Benefit Cost	'																									'
	Assumptions used to determine the benefit obligation at December 31 and net periodic benefit cost for the year ended December 31 are detailed below:
			Pension Benefits											Other Benefits
			2013						2012					2013						2012
			U.S.			International			U.S.			International		U.S.			International			U.S.			International
	Actuarial assumptions used to determine benefit obligations at December 31:
	Discount rate		4.5	%		4.5	%		3.75	%		3.75	%	4.5	%		4.5	%		3.75	%		3.75	%
	Increase in compensation rate		4	%		3	%		4	%		3	%	4	%		3	%		4	%		3	%
			Pension Benefits
			2013						2012					2011
			U.S.			International			U.S.			International		U.S.			International
	Actuarial assumptions used to determine net periodic benefit cost for the year ended December 31:
	Discount rate		3.75	%		3.75	%		4.5	%		4.5	%	5	%		5	%
	Expected annual return on plan assets		7.75	%		7.25	%		7.75	%		7.25	%	8	%		7.5	%
	Increase in compensation rate		4	%		3	%		4	%		3	%	4	%		3	%
			Other Benefits
			2013						2012					2011
			U.S.			International			U.S.			International		U.S.			International
	Discount rate		3.75	%		3.75	%		4.5	%		4.5	%	5	%		5	%
	Expected annual return on plan assets		7.75	%		n/a			7.75	%		n/a		8	%		n/a
	Increase in compensation rate		4	%		3	%		4	%		3	%	4	%		3	%
Assumed Health Care Cost Trend Rates	'																									'
			2013				2012
	Assumed health care cost trend rates at December 31:		U.S.		Canada		U.S.		Canada
	Health care cost trend rate assumed for next year		7.00%		6.00%		7.00%		6.00%
	Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)		5.00%		5.00%		5.00%		5.00%
	Year that the rate reaches the ultimate trend rate		2018		2018		2017		2017
Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates	'																									'
	A one-percentage-point change in the assumed return on plan assets, discount rate or health care cost trend rates would have the following effects:
	(In millions)		1-Percentage-				1-Percentage-
			Point Increase				Point Decrease
	Expected return on plan assets
	Incremental (decrease) increase in:
	Net periodic pension costs for 2014		$	(100	)		$	100
	Discount rate
	Incremental (decrease) increase in:
	Net periodic pension & other benefits costs for 2014		$	(39	)		$	55
	Pension & other benefits liabilities at December 31, 2013		$	(1,191	)		$	1,418
	Health care cost escalation trend rates
	Incremental increase (decrease) in:
	Other postretirement benefit obligations		$	191			$	(161	)
	Service and interest costs components		$	10			$	(8	)
Pension Plan and Other Benefits Plan Assets, Classification	'																									'
	U. S. Steel’s Pension plan and Other Benefits plan assets are classified as follows:
	Level 1		Level 2		Level 3
	Investment Trusts		Internally Managed Partnerships		Private Equities
	Exchange-traded Funds		Non-public Investment Partnerships		Timberlands
	Short-term Investments		Debt Securities - U.S.		Real Estate
	Equity Securities - U.S.		Debt Securities - Foreign		Mineral Interests
	Equity Securities - Foreign		Pooled Funds
	Government Bonds - U.S.		Government Bonds - Foreign
Multiemployer Pension Plans	'																									'
	U. S. Steel’s participation in the SPT for the annual periods ended December 31, 2013, 2012 and 2011 is outlined in the table below.
			Employer		Pension				FIP/RP Status		U.S. Steel											Surcharge			Expiration Date
			Identification		Protection				Pending/		Contributions											Imposed(c)			of Collective
			Number/		Act Zone				Implemented(b)		(in millions)														Bargaining
			Pension Plan		Status as of																				Agreement
			Number		December 31(a)
	Pension Fund				2013		2012				2013			2012				2011				2013		2012
	Steelworkers Pension Trust		23-6648508/499		Green		Green		No		$	74		$	69			$	63			No		No	September 1, 2015
	(a)	The zone status is based on information that U. S. Steel received from the plan and is certified by the plan’s actuary. Among other factors, plans in the green zone are at least 80 percent funded, while plans in the yellow zone are less than 80 percent funded and plans in the red zone are less than 65 percent funded.
	(b)	Indicates if a financial improvement plan (FIP) or a rehabilitation plan (RP) is either pending or has been implemented.
	(c)	Indicates whether there were charges to U. S. Steel from the plan.
Benefit Payments Expected to be Paid from Defined Benefit Plans	'																									'
	Estimated Future Benefit Payments – The following benefit payments, which reflect expected future service as appropriate, are expected to be paid from U. S. Steel’s defined benefit plans:
	(In millions)		Pension				Other
			Benefits				Benefits
	2014		$	955			$	266
	2015		808				285
	2016		796				280
	2017		789				241
	2018		771				232
	Years 2019 - 2023		3,563				1,077
Pension Benefits	'																									'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'																									'
Pension and Other Benefits Plan Assets Carried at Fair Value	'																									'
	The following is a summary of U. S. Steel’s Pension plan assets carried at fair value at December 31, 2013 and 2012:																									The following is a summary of U. S. Steel’s Pension plan assets carried at fair value at December 31, 2013 and 2012:
			Fair Value Measurements at December 31, 2013 (in millions)																									Fair Value Measurements at December 31, 2013 (in millions)
			Total				Quoted Prices in				Significant			Significant														Total		Quoted Prices in		Significant		Significant
							Active Markets				Observable			Unobservable																Active Markets		Observable		Unobservable
							(Level 1)				Inputs			Inputs																(Level 1)		Inputs		Inputs
											(Level 2)			(Level 3)																		(Level 2)		(Level 3)
	Asset Classes																									Asset Classes
	Interest in Internally Managed Partnership – Fixed Income(a)		$	1,830			$	—			$	1,830		$	—											Interest in Internally Managed Partnership – Fixed Income(a)		$	1,830	$	—	$	1,830	$	—
	Interest in Internally Managed Partnership – Equity(b)		3,658				—				3,658			—												Interest in Internally Managed Partnership – Equity(b)		3,658		—		3,658		—
	Interest in Investment Partnerships(c)		823				—				823			—												Interest in Investment Partnerships(c)		823		—		823		—
	Equity securities – Foreign(d)		444				444				—			—												Equity securities – Foreign(d)		444		444		—		—
	Pooled funds(e)		540				—				540			—												Pooled funds(e)		540		—		540		—
	Timberlands		302				—				—			302												Timberlands		302		—		—		302
	Private equities		306				—				—			306												Private equities		306		—		—		306
	Real estate		301				—				—			301												Real estate		301		—		—		301
	Other(f)		918				458				456			4												Other(f)		918		458		456		4
	Total		$	9,122			$	902			$	7,307		$	913											Total		$	9,122	$	902	$	7,307	$	913
	(a)	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which United States Steel and Carnegie Pension Fund (UCF) acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:																								(a)	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which United States Steel and Carnegie Pension Fund (UCF) acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
	Debt Securities – U.S.	$	1,127																							Debt Securities – U.S.	$	1,127
	Government Bonds – U.S.	629																								Government Bonds – U.S.	629
	Agency Mortgages	65																								Agency Mortgages	65
	Other	9																								Other	9
	Total	$	1,830																							Total	$	1,830
	(b)	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:																								(b)	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
	Equity Securities – U.S.	$	3,346																							Equity Securities – U.S.	$	3,346
	Equity Securities – Foreign	181																								Equity Securities – Foreign	181
	Investment sales receivable	130																								Investment sales receivable	130
	Other	1																								Other	1
	Total	$	3,658																							Total	$	3,658
	(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.																								(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
	(d)	Includes investments held in a diversified portfolio of Canadian equity securities with no single sector representing more than 30 percent of the portfolio by value.																								(d)	Includes investments held in a diversified portfolio of Canadian equity securities with no single sector representing more than 30 percent of the portfolio by value.
	(e)	Investments in funds incorporated in Canada that invest in diversified portfolios of global debt and equity securities.																								(e)	Investments in funds incorporated in Canada that invest in diversified portfolios of global debt and equity securities.
	(f)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes interests in investment trusts, exchange-traded funds, equity securities – U.S., short-term investments, government bonds - foreign, debt securities – foreign, mineral interests and miscellaneous receivables and payables.																								(f)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes interests in investment trusts, exchange-traded funds, equity securities – U.S., short-term investments, government bonds - foreign, debt securities – foreign, mineral interests and miscellaneous receivables and payables.
																												Fair Value Measurements at December 31, 2012 (in millions)
																												Total		Quoted Prices in		Significant		Significant
																														Active Markets		Observable		Unobservable
																														(Level 1)		Inputs		Inputs
																																(Level 2)		(Level 3)
																										Asset Classes
																										Interest in Internally Managed Partnership – Fixed Income(a)		$	1,688	$	—	$	1,688	$	—
																										Interest in Internally Managed Partnership – Equity(b)		3,491		—		3,491		—
																										Interest in Investment Partnerships(c)		608		—		608		—
																										Equity securities – Foreign(d)		482		482		—		—
																										Government bonds – Foreign(e)		499		—		499		—
																										Pooled funds(f)		312		—		312		—
																										Private equities		342		—		—		342
																										Real estate		300		—		—		300
																										Other(g)		937		503		193		241
																										Total		$	8,659	$	985	$	6,791	$	883
																										(a)	UCF Fixed Income Fund LP - a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
																										Debt Securities – U.S.	$	1,112
																										Government Bonds – U.S.	473
																										Agency Mortgages	85
																										Other	18
																										Total	$	1,688
																										(b)	UCF Equity Fund LP - a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
																										Equity Securities – U.S.	$	3,166
																										Equity Securities – Foreign	149
																										Investment sales receivable	111
																										Other	65
																										Total	$	3,491
																										(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
																										(d)	Includes investments held in a diversified portfolio of Canadian equity securities with no single sector representing more than 30 percent of the portfolio by value.
																									(e)	Includes investments in Canadian National and Provincial government bonds.
																									(f)	Investments in funds incorporated in Canada that invest in diversified portfolios of global debt and equity securities.
																									(g)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes interests in investment trusts, exchange-traded funds, short-term investments, government bonds – U.S., debt securities – U.S., debt securities – foreign, timberlands, mineral interests and miscellaneous receivables and payables.
Changes in Fair Value of Pension and Other Benefits Plan Level 3 Assets	'																									'
	The following table sets forth a summary of changes in the fair value of U. S. Steel’s Pension plan Level 3 assets for the years ended December 31, 2013 and 2012 (in millions):
			Other
			(Level 3 assets only)
			2013				2012
	Balance at beginning of period		$	883			$	850
	Transfers in and/or out of Level 3		—				—
	Actual return on plan assets:
	Realized gain		89				69
	Net unrealized gain		45				8
	Purchases, sales, issuances and settlements:
	Purchases		102				98
	Sales		(206		)		(142		)
	Balance at end of period		$	913			$	883
Other Benefits	'																									'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'																									'
Pension and Other Benefits Plan Assets Carried at Fair Value	'																									'
	The following is a summary of U. S. Steel’s Other Benefits plan assets carried at fair value at December 31, 2013 and 2012:																									The following is a summary of U. S. Steel’s Other Benefits plan assets carried at fair value at December 31, 2013 and 2012:
			Fair Value Measurements at December 31, 2013 (in millions)																									Fair Value Measurements at December 31, 2013 (in millions)
			Total				Quoted Prices in				Significant			Significant														Total		Quoted Prices in		Significant		Significant
							Active Markets				Observable			Unobservable																Active Markets		Observable		Unobservable
							(Level 1)				Inputs			Inputs																(Level 1)		Inputs		Inputs
											(Level 2)			(Level 3)																		(Level 2)		(Level 3)
	Asset Classes																									Asset Classes
	Interest in Internally Managed Partnership – Fixed Income (a)		$	513			$	—			$	513		$	—											Interest in Internally Managed Partnership – Fixed Income (a)		$	513	$	—	$	513	$	—
	Interest in Internally Managed Partnership – Equity(b)		1,190				—				1,190			—												Interest in Internally Managed Partnership – Equity(b)		1,190		—		1,190		—
	Interest in Investment Partnerships(c)		131				—				131			—												Interest in Investment Partnerships(c)		131		—		131		—
	All Other(d)		136				37				—			99												All Other(d)		136		37		—		99
	Total		$	1,970			$	37			$	1,834		$	99											Total		$	1,970	$	37	$	1,834	$	99
	(a)	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:																								(a)	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
	Debt Securities – U.S.	$	308																							Debt Securities – U.S.	$	308
	Government Bonds – U.S.	172																								Government Bonds – U.S.	172
	Agency Mortgages	18																								Agency Mortgages	18
	Partner contribution receivable	19																								Partner contribution receivable	19
	Other	(4		)																						Other	(4		)
	Total	$	513																							Total	$	513
	(b)	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:																								(b)	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
	Equity Securities – U.S.	$	1,081																							Equity Securities – U.S.	$	1,081
	Equity Securities – Foreign	59																								Equity Securities – Foreign	59
	Exchange-traded funds	42																								Exchange-traded funds	42
	Other	8																								Other	8
	Total	$	1,190																							Total	$	1,190
	(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.																								(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
	(d)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes short-term investments, exchange-traded funds, private equities, real estate, timberlands and miscellaneous receivables and payables.																								(d)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes short-term investments, exchange-traded funds, private equities, real estate, timberlands and miscellaneous receivables and payables.
			Fair Value Measurements at December 31, 2012 (in millions)
			Total				Quoted Prices in				Significant			Significant
							Active Markets				Observable			Unobservable
							(Level 1)				Inputs			Inputs
											(Level 2)			(Level 3)
	Asset Classes
	Interest in Internally Managed Partnership – Fixed Income(a)		$	468			$	—			$	468		$	—
	Interest in Internally Managed Partnership – Equity(b)		1,061				—				1,061			—
	Interest in Investment Partnerships(c)		94				—				94			—
	All Other(d)		109				38				—			71
	Total		$	1,732			$	38			$	1,623		$	71
	(a)	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
	Debt Securities – U.S.	$	308
	Government Bonds – U.S.	131
	Agency Mortgages	24
	Other	5
	Total	$	468
	(b)	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:
	Equity Securities – U.S.	$	950
	Equity Securities – Foreign	45
	Investment sales receivable	33
	Other	33
	Total	$	1,061
	(c)	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
	(d)	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes short-term investments, exchange-traded funds, private equities, real estate, timberlands and miscellaneous receivables and payables.
Changes in Fair Value of Pension and Other Benefits Plan Level 3 Assets	'																									'
	The following table sets forth a summary of changes in the fair value of U. S. Steel’s Other Benefits plan Level 3 assets for the years ended December 31, 2013 and 2012 (in millions):
			Other
			(Level 3 assets only)
			2013				2012
	Balance at beginning of period		$	71			$	57
	Transfers in and/or out of Level 3		—				—
	Actual return on plan assets:
	Realized gain		8				2
	Net unrealized gain		6				3
	Purchases, sales, issuances and settlements:
	Purchases		29				17
	Sales		(15		)		(8		)
	Balance at end of period		$	99			$	71

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2013
Asset Retirement Obligation Disclosure [Abstract]	'
Changes in Carrying Values of Asset Retirement Obligations	'
	The following table reflects changes in the carrying values of AROs for the years ended December 31, 2013 and 2012:
		December 31,
	(In millions)	2013			2012
	Balance at beginning of year	$	33		$	38
	Additional obligations incurred	28			2
	Obligations settled	(7		)	(9		)
	Accretion expense	5			2
	Balance at end of period	$	59		$	33

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Financial Assets and Liabilities Not Carried at Fair Value	'
	The following table summarizes U. S. Steel’s financial assets and liabilities that were not carried at fair value at December 31, 2013 and 2012.
		December 31, 2013				December 31, 2012
	(In millions)	Fair Value		Carrying		Fair Value		Carrying
				Amount				Amount
	Financial assets:
	Investments and long-term receivables (a)	$	63	$	63	$	39	$	39
	Financial liabilities:
	Debt (b)	$	4,198	$	3,904	$	4,113	$	3,902
	(a)Excludes equity method investments.
	(b)Excludes borrowings under the RPA and capital lease obligations.

Reclassifications_from_Accumul1

Reclassifications from Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	Reclassifications from Accumulated Other Comprehensive Income (AOCI)
	(in millions) (a)		Pension and				Foreign				Total
			Other Benefit				Currency
			Items				Items
	Balance at December 31, 2011		$	(3,598	)		$	231			$	(3,367	)
	Other comprehensive income (loss) before reclassifications		(278		)		114				(164		)
	Amounts reclassified from AOCI (b)		263				—				263
	Net current-period other comprehensive income		(15		)		114				99
	Balance at December 31, 2012		$	(3,613	)		$	345			$	(3,268	)
	Other comprehensive income (loss) before reclassifications		1,220				52				1,272
	Amounts reclassified from AOCI		266			(b)	(22		)	(c)	244
	Net current-period other comprehensive income		1,486				30				1,516
	Balance at December 31, 2013		$	(2,127	)		$	375			$	(1,752	)
	(a)All amounts are net of tax. Amounts in parentheses indicate debits.
	(b)See table below for further details.
Amounts Recognized in Accumulated Other Comprehensive Loss	'
	Amounts recognized in accumulated other comprehensive loss:
							2013
	(In millions)		12/31/12				Amortization				Activity			12/31/13
	Pensions
	Prior Service Cost		$	99			$	(24	)		$	1		$	76
	Actuarial losses		4,656				(367		)		(1,165		)	3,124
	Other Benefits
	Prior Service Cost		(180		)		13				—			(167		)
	Actuarial Losses		613				(31		)		(632		)	(50		)
					Amount reclassified
					from AOCI
	(In millions) (a)		Details about AOCI components		2013				2012
			Amortization of pension and other benefit items
			Prior service costs		$	(11	)		$	(33	)	(b)
			Actuarial gains/(losses)		(398		)		(360		)	(b)
			Total before tax		(409		)		(393		)
			Tax benefit		143				130
			Net of tax		$	(266	)		$	(263	)
	(a)Amounts in parentheses indicate debits to income/loss.
	(b)	These AOCI components are included in the computation of net periodic benefit cost (see Note 16 for additional details).

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2013
Supplemental Cash Flow Elements [Abstract]	'
Supplemental Cash Flow Information	'
	(In millions)	2013			2012			2011
	Net cash used in operating activities included:
	Interest and other financial costs paid (net of amount capitalized)	$	(238	)	$	(239	)	$	(222	)
	Income taxes (paid) refunded	$	(20	)	$	(71	)	$	13
	Non-cash investing and financing activities:
	Change in accrued capital expenditures	$	(14	)	$	(52	)				(a)
	Assets acquired under capital lease	$	—		$	35		$	—
	U. S. Steel common stock issued for employee stock plans	$	—		$	2		$	—
	(a)The change in accrued capital expenditures was insignificant for the year ended December 31, 2011.

Leases_Tables

Leases (Tables)	12 Months Ended
	Dec. 31, 2013
Leases [Abstract]	'
Future Minimum Commitments for Capital Leases and Operating Leases	'
	Future minimum commitments for capital leases (including sale-leasebacks accounted for as financings) and for operating leases having initial non-cancelable lease terms in excess of one year are as follows:
	(In millions)	Capital		Operating
		Leases		Leases
	2014	$	5	$	76
	2015	5		71
	2016	5		63
	2017	5		45
	2018	5		14
	Later years	26		31
	Sublease rentals	—		—
	Total minimum lease payments	$	51	$	300
	Less imputed interest costs	16
	Present value of net minimum lease payments included in long-term debt (see Note 14)	$	35
Operating Lease Rental Expense	'
	Operating lease rental expense:
	(In millions)	2013		2012		2011
	Minimum rentals	$	111	$	91	$	95
	Contingent rentals	11		12		11
	Sublease rentals	—		—		—
	Net rental expense	$	122	$	103	$	106

Restructuring_and_Other_Charge1

Restructuring and Other Charges (Tables)	12 Months Ended
	Dec. 31, 2013
Restructuring and Related Activities [Abstract]	'
Activity in Accrued Balances for Restructuring and Other Cost Reduction Programs	'
	The activity in the accrued balances and the non-cash charges and credits incurred in relation to restructuring and other cost reduction programs during the year ended December 31, 2013 were as follows:
		Severance			Exit			Accelerated
	(in millions)	Accrual			Costs			Depreciation
	Balance at December 31, 2012	$	—		$	—		$	—
	Additional charges	16		(a)	6		(b)	222			(c)
	Cash payments/utilization	—			—			(222		)
	Other adjustments and re-classes	—			—			—
	Balance at December 31, 2013	$	16		$	6		$	—
	(a) Amount relates to charges recognized for severance benefits for approximately 180 employees terminated at Hamilton Works and Lake Erie Works and excludes associated pension curtailment charges of approximately $4 million (see Note 16).
	(b) Amount relates to exit costs associated with the closure of the WGN.
	(c) Accelerated depreciation charges are related to the closure of the iron and steelmaking facilities at Hamilton Works and assets related to WGN.
Balance Sheet Location of Accrued Liabilities for Restructuring and Other Cost Reduction Programs	'
	Accrued liabilities for restructuring and other cost reduction programs are included in the following balance sheet lines:
	(in millions)	December 31, 2013			December 31, 2012
	Accounts payable	$	6		$	—
	Payroll and benefits payable	8			—
	Employee benefits	8			—
	Total	$	22		$	—

Contingencies_and_Commitments_

Contingencies and Commitments (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
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:
		Twelve Months Ended December 31,
	(In millions)	2013			2012
	Beginning of period	$	203		$	206
	Accruals for environmental remediation deemed probable and reasonably estimable	45			13
	Payments	(15		)	(16		)
	End of period	$	233		$	203
Accrued Liabilities for Remediation Activities Included in Balance Sheet	'
	Accrued liabilities for remediation activities are included in the following balance sheet lines:
	(In millions)	December 31, 2013			December 31, 2012
	Accounts payable	$	17		$	21
	Deferred credits and other noncurrent liabilities	216			182
	Total	$	233		$	203
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):
	2014	2015		2016	2017		2018	Later years	Total
	$854	$644		$411	$326		$296	$1,443	$3,974

Nature_of_Business_and_Signifi2

Nature of Business and Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended			3 Months Ended	12 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Jan. 31, 2012	Mar. 31, 2012	Dec. 31, 2012
				Restatement Adjustment	Restatement Adjustment	Maximum	USSS	USSS	USSS
					adjustment
Significant Accounting Policies [Line Items]	'	'	'	'	'	'	'	'	'
Percentage of LIFO (last in first out) inventory to total inventory	59.00%	56.00%	'	'	'	'	'	'	'
Impairment of goodwill	$1,806	$0	$0	'	'	'	'	'	'
Gain (loss) on sale of asset	'	'	'	'	'	'	-399	-399	-399
Percentage of employees covered by Steelworkers Pension Trust (SPT)	60.00%	'	'	'	'	'	'	'	'
Percentage of gross annual revenues accounted for by single customer	'	'	'	'	'	10.00%	'	'	'
Reclassification of deferred tax assets to current from non-current	122	'	'	'	'	'	'	'	'
Number of out of period adjustments	'	'	'	'	2	'	'	'	'
Discrete tax benefit included in tax benefit, to adjust state deferred taxes	'	'	'	13	'	'	'	'	'
Charge included in tax benefit to adjust deferred taxes for prior years' differences between the financial statement carrying amounts of assets and liabilities and their tax bases	'	'	'	19	'	'	'	'	'
Out of period adjustment, increase in fixed assets and net income	'	'	$10	'	'	'	'	'	'

Segment_Information_Results_of

Segment Information - Results of Segment Operations (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]	'	'	'
Net Sales	$17,424	$19,328	$19,884
Income (loss) from investees	40	144	85
Income (loss) from operations	-1,900	247	265
Depreciation, depletion & amortization	684	661	681
Capital expenditures	477	723	848
Flat-rolled	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	12,830	14,555	13,727
Income (loss) from investees	69	152	98
Income (loss) from operations	105	400	469
Depreciation, depletion & amortization	512	491	485
Capital expenditures	349	625	616
USSE	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	2,944	3,094	4,375
Income (loss) from investees	0	0	1
Income (loss) from operations	28	34	-162
Depreciation, depletion & amortization	95	102	140
Capital expenditures	40	38	109
Tubular	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	2,777	3,291	3,041
Income (loss) from investees	-25	-6	-14
Income (loss) from operations	190	366	316
Depreciation, depletion & amortization	62	58	44
Capital expenditures	69	42	104
Total reportable segments	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	18,551	20,940	21,143
Income (loss) from investees	44	146	85
Income (loss) from operations	323	800	623
Depreciation, depletion & amortization	669	651	669
Capital expenditures	458	705	829
Other Businesses	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	273	327	522
Income (loss) from investees	-4	-2	0
Income (loss) from operations	77	55	46
Depreciation, depletion & amortization	15	10	12
Capital expenditures	19	18	19
Reconciling Items and Eliminations	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	-1,400	-1,939	-1,781
Income (loss) from investees	0	0	0
Income (loss) from operations	-2,300	-608	-404
Depreciation, depletion & amortization	0	0	0
Capital expenditures	0	0	0
Customer Sales	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	17,424	19,328	19,884
Customer Sales | Flat-rolled	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	11,572	12,908	12,367
Customer Sales | USSE	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	2,941	2,949	4,306
Customer Sales | Tubular	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	2,772	3,283	3,034
Customer Sales | Total reportable segments	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	17,285	19,140	19,707
Customer Sales | Other Businesses	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	139	188	177
Customer Sales | Reconciling Items and Eliminations	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	0	0	0
Intersegment Sales	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	0	0	0
Intersegment Sales | Flat-rolled	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	1,258	1,647	1,360
Intersegment Sales | USSE	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	3	145	69
Intersegment Sales | Tubular	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	5	8	7
Intersegment Sales | Total reportable segments	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	1,266	1,800	1,436
Intersegment Sales | Other Businesses	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	134	139	345
Intersegment Sales | Reconciling Items and Eliminations	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Sales	($1,400)	($1,939)	($1,781)

Segment_Information_Schedule_o

Segment Information - Schedule of Reconciling Items to Income (Loss) from Operations (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Other items not allocated to segments:	'	'		'		'
Impairment of goodwill	'	($1,806)		$0		$0
Restructuring and other charges	'	-248		0		0
Environmental remediation charge	'	-45		-13		-36
Labor agreement lump sum payments	-35	'		'		'
(Loss) income from operations	'	-1,900		247		265
Reconciling Items and Eliminations	'	'		'		'
Items not allocated to segments:	'	'		'		'
Postretirement benefit expense	'	-221	[1]	-297	[1]	-386	[1]
Other items not allocated to segments:	'	'		'		'
Impairment of goodwill	'	-1,806		0		0
Restructuring and other charges	'	-248		0		0
Environmental remediation charge	'	-32		0		-18
Supplier contract dispute settlement	'	23		15		0
Net loss on the sale of assets	'	0		-310		0
Labor agreement lump sum payments	'	0		-35		0
Property tax settlements	'	0		19		0
Total other items not allocated to segments	'	-2,079		-311		-18
(Loss) income from operations	'	-2,300		-608		-404
United Spiral Pipe, LLC	'	'		'		'
Other items not allocated to segments:	'	'		'		'
Write-off of equity investment	'	'		0		0
United Spiral Pipe, LLC | Reconciling Items and Eliminations	'	'		'		'
Other items not allocated to segments:	'	'		'		'
Write-off of equity investment	'	($16)		'		'
[1]	Consists of the net periodic benefit cost elements, other than service cost and amortization of prior service cost for active employees, associated with our pension, retiree health care and life insurance benefit plans.

Segment_Information_Net_Sales_

Segment Information - Net Sales by Product (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]	'		'		'
Total	$17,424		$19,328		$19,884
Other	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Total	1,090	[1]	1,361	[1]	1,037	[1]
Flat-rolled	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Total	13,508		14,721		15,861
Tubular Segment	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Total	$2,826		$3,246		$2,986
[1]	Primarily includes sales of steel production by-products, railroad services and real estate operations.

Segment_Information_Net_Sales_1

Segment Information - Net Sales, Property, Plant and Equipment and Equity Method Investments Based on Location of Operating Segment (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]	'		'		'
Net Sales	$17,424		$19,328		$19,884
Assets	6,480		6,978		7,230
North America	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Net Sales	14,484	[1]	16,379	[1]	15,578	[1]
Assets	5,425	[1]	5,907	[1]	5,869	[1]
Europe	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Net Sales	2,940	[2]	2,949	[2]	4,306	[2]
Assets	1,022	[2]	1,034	[2]	1,321	[2]
Other Foreign Countries	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Net Sales	0		0		0
Assets	33		37		40
United States	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Assets	4,443		4,523		4,424
Slovakia	'		'		'
Segment Reporting Information [Line Items]	'		'		'
Assets	$1,022		$1,034		$1,064
[1]	Assets with a book value of $4,443 million, $4,523 million and $4,424 million were located in the United States at December 31, 2013, 2012 and 2011, respectively.
[2]	Assets with a book value of $1,022 million, $1,034 million and $1,064 million were located in Slovakia at December 31, 2013, 2012 and 2011, respectively.

Segment_Information_Additional

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013
	Segment
Segment Reporting [Abstract]	'
Number of reportable segments	3

Dispositions_and_Assets_Held_f1

Dispositions and Assets Held for Sale - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended	12 Months Ended
	Feb. 29, 2012	Jan. 31, 2012	Mar. 31, 2012	Dec. 31, 2012
	Birmingham Southern Railroad Company	USSS	USSS	USSS
Significant Acquisitions and Disposals [Line Items]	'	'	'	'
Gain (loss) on sale of asset	$89,000,000	($399,000,000)	($399,000,000)	($399,000,000)
Proceed from sale of USSS	'	1	'	'
Additional payment received by USSK for intercompany balances owed by USSS	'	$40,000,000	'	'

Net_Interest_and_Other_Financi2

Net Interest and Other Financial Costs (Detail) (USD $)	12 Months Ended						1 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011		Mar. 31, 2013	Dec. 31, 2013	4-May-09
							2014 Senior Convertible Notes	2014 Senior Convertible Notes	2014 Senior Convertible Notes
Net Interest and Other Fnancial Costs [Line Items]	'		'		'		'	'	'
Loss on repurchase of notes	'		'		'		$34	'	'
Redemption of notes	'		'		'		542	'	'
Stated interest rate	'		'		'		'	4.00%	4.00%
Charge for guarantee in unconsolidated equity method investment during the period	22	[1]	'		'		'	'	'
Interest income:	'		'		'		'	'	'
Interest income	-3		-7		-6		'	'	'
Interest expense and other financial costs:	'		'		'		'	'	'
Interest incurred(a)	285	[2]	255	[2]	229	[2]	'	'	'
Less interest capitalized	19		41		39		'	'	'
Total interest expense	266		214		190		'	'	'
Foreign currency net loss	11	[1]	7	[1]	27	[1]	'	'	'
Financial costs on:	'		'		'		'	'	'
Sale of receivables	3		4		4		'	'	'
Amended Credit Agreement	4		4		5		'	'	'
USSK credit facilities	3		3		2		'	'	'
Other	28	[1]	0	[1]	0	[1]	'	'	'
Amortization of discounts and deferred financing costs	20		16		16		'	'	'
Total other financial costs	69		34		54		'	'	'
Net interest and other financial costs	$332		$241		$238		'	'	'
[1]	Consists primarily of a charge of $22 million in 2013 related to a guarantee of an unconsolidated equity investment for which payment by U. S. Steel is probable (see Note 24).
[2]	Includes a pretax charge of $34 million during 2013 related to premiums on the repurchase of $542 million of our 4.00% Senior Convertible Notes.

Income_and_Dividends_Per_Commo2

Income and Dividends Per Common Share - Computations for Basic and Diluted Income (Loss) Per Common Share from Continuing Operations (Detail) (USD $)	12 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]	'	'	'
Net loss attributable to United States Steel Corporation shareholders	($1,672)	($124)	($53)
Plus income effect of assumed conversion-interest on convertible notes	0	0	0
Net loss after assumed conversion	($1,672)	($124)	($53)
Weighted-average shares outstanding:	'	'	'
Basic (in shares)	144,578	144,237	143,967
Effect of convertible notes (in shares)	0	0	0
Effect of stock options, restricted stock units and performance awards (in shares)	0	0	0
Adjusted weighted-average shares outstanding, diluted (in shares)	144,578	144,237	143,967
Basic loss per common share	($11.56)	($0.86)	($0.37)
Diluted loss per common share	($11.56)	($0.86)	($0.37)

Income_and_Dividends_Per_Commo3

Income and Dividends Per Common Share - Antidilutive Securities that were Not Included in Computation of Diluted Loss Per Common Share (Detail) (USD $)

12 Months Ended

0 Months Ended

12 Months Ended

In Millions, except Share data in Thousands, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Mar. 27, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

2014 Senior Convertible Notes

2014 Senior Convertible Notes

Securities granted under the 2005 Stock Incentive Plan

Securities granted under the 2005 Stock Incentive Plan

Securities granted under the 2005 Stock Incentive Plan

Securities convertible under the Senior Convertible Notes

Securities convertible under the Senior Convertible Notes

Securities convertible under the Senior Convertible Notes

Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]

'

'

'

'

'

'

'

'

'

'

'

Antidilutive securities excluded from computation of diluted loss per common share

21,056

32,640

30,971

'

'

7,039

5,581

3,912

14,017

[1]

27,059

27,059

Repurchase of convertible notes

'

'

'

$542

'

'

'

'

'

'

'

Stated interest rate

'

'

'

'

4.00%

'

'

'

'

'

'

Antidilutive securities assumed excluded from computation of diluted loss per common share, if repurchases had occurred on January 1, 2013

'

'

'

'

10,058

'

'

'

'

'

'

[1]

On March 27, 2013, we repurchased approximately $542 million aggregate principal amount of our 4% Senior Convertible Notes due in 2014. If the repurchases had occurred on January 1, 2013, the antidilutive securities would have been 10,058 thousand for the year ended December 31, 2013.

Income_and_Dividends_Per_Commo4

Income and Dividends Per Common Share - Additional Information (Detail) (USD $)

3 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 31, 2011

Earnings Per Share [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

Quarterly dividends per common share

$0.05

$0.05

$0.05

$0.05

$0.05

$0.05

$0.05

$0.05

$0.05

$0.05

$0.05

$0.05

Inventories_Detail

Inventories (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Raw materials	$1,011	$945
Semi-finished products	1,023	883
Finished products	558	573
Supplies and sundry items	96	102
Total	$2,688	$2,503

Inventories_Additional_Informa

Inventories - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Inventory Disclosure [Line Items]	'	'	'
Estimate in excess of current acquisition costs over stated inventory values	$1,000,000,000	$1,000,000,000	'
(Decrease) increase in income from operations as a result of liquidations of LIFO inventories	-9,000,000	27,000,000	3,000,000
Inventory write down	'	35,000,000	85,000,000
Land held for residential or commercial development	$81,000,000	$86,000,000	'
Coke | Swap agreement	'	'	'
Inventory Disclosure [Line Items]	'	'	'
Amount of commodity shipped under swap agreement (in tons)	1,025,000	900,000	'
Amount of commodity received under swap agreement (in tons)	1,025,000	900,000	'
Iron ore pellet | Swap agreement	'	'	'
Inventory Disclosure [Line Items]	'	'	'
Amount of commodity shipped under swap agreement (in tons)	3,145,000	2,855,000	'
Amount of commodity received under swap agreement (in tons)	3,145,000	2,855,000	'

Income_Taxes_Provisions_Benefi

Income Taxes - Provisions (Benefits) for Income Taxes (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current Provisions (Benefits) for Income Taxes	'	'	'
Current Federal Income tax (benefit) provision	($210)	$48	$148
Current State and local Income tax (benefit) provision	8	5	-2
Current Foreign Income tax (benefit) provision	1	4	2
Current Income tax (benefit) provision	-201	57	148
Deferred Provisions (Benefits) for Income Taxes	'	'	'
Deferred Federal Income tax (benefit) provision	-167	61	-92
Deferred State and local Income tax (benefit) provision	-50	23	15
Deferred Foreign Income tax (benefit) provision	-142	-10	9
Deferred Income tax (benefit) provision	-359	74	-68
Provisions (Benefits) for Income Taxes, Total	'	'	'
Federal Income tax (benefit) provision	-377	109	56
State and local Income tax (benefit) provision	-42	28	13
Foreign Income tax (benefit) provision	-141	-6	11
Total (benefit) provision	($560)	$131	$80

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Federal Statutory Tax to Total Provisions (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Statutory rate applied to income (loss) before income taxes	($781)	$2	$9
Effects of foreign operations	467	266	184
Worthless stock loss and bad debt deduction	-417	0	0
Goodwill impairment	410	0	0
Tax accounting benefit related to increase in OCI	-142	0	0
Excess percentage depletion	-94	-107	-102
State and local income taxes after federal income tax effects	-27	18	8
Adjustments of prior years’ federal income taxes	9	-46	-11
Tax credits	-3	0	-3
Deduction for domestic production activities	12	-7	-8
Medicare Part D drug program subsidies	0	-1	-6
Other	6	6	9
Total (benefit) provision	($560)	$131	$80

Income_Taxes_Reconciliation_of1

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of unrecognized tax benefits [Roll Forward]:	'	'	'
Unrecognized tax benefits, beginning of year	$85	$110	$115
Increases - tax positions taken in prior years	1	3	1
Decreases - tax positions taken in prior years	-6	-25	-4
Increases - current tax positions	70	2	3
Settlements	0	-5	0
Lapse of statute of limitations	-23	0	-5
Unrecognized tax benefits, end of year	$127	$85	$110

Income_Taxes_Deferred_Tax_Asse

Income Taxes - Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Deferred tax assets:	'	'
Federal tax loss carryforwards (expiring in 2033)	$386	$0
State tax credit carryforwards (expiring in 2027)	7	2
State tax loss carryforwards (expiring in 2015 through 2033)	37	35
Minimum tax credit carryforwards	108	157
General business credit carryforwards	69	66
Foreign tax loss and credit carryforwards (expiring in 2014 through 2033)	713	637
Employee benefits	908	1,704
Receivables, payables and debt	88	89
Expected federal benefit for deducting state deferred income taxes	32	51
Inventory	107	0
Contingencies and accrued liabilities	119	133
Valuation allowances:	'	'
Total deferred tax assets	1,546	1,775
Deferred tax liabilities:	'	'
Property, plant and equipment	1,205	1,041
Investments in subsidiaries and equity investees	50	97
Inventory	0	1
Future reduction of foreign tax credits	49	0
Other temporary differences	95	41
Total deferred tax liabilities	1,399	1,180
Net deferred tax asset	147	595
Foreign Country	'	'
Valuation allowances:	'	'
Deferred tax assets valuation allowances	($1,028)	($1,099)

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

3 Months Ended

12 Months Ended

2 Months Ended

3 Months Ended

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jan. 31, 2012

Mar. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Feb. 25, 2014

Dec. 31, 2013

Slovakia

Domestic Country

Domestic Country

Domestic Country

Foreign Country

Foreign Country

Foreign Country

USSS

USSS

USSS

Goodwill

Subsequent Event

Restatement Adjustment

Slovakia

Income Taxes [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Statutory tax rate

'

35.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Tax Benefit for Worthless Security and Bad Debt Deductions

$392,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Translation Adjustment Functional to Reporting Currency, Tax Benefit (Expense)

'

22,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Increase (Decrease) in Income Taxes Payable

'

-66,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Federal Income Tax Refund

176,000,000

176,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Tax Benefit to Offset Future Year Federal Income Taxes

'

150,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Income tax provision (benefit)

'

-560,000,000

131,000,000

80,000,000

'

'

'

'

'

'

'

'

'

'

0

0

'

'

Impairment of goodwill

'

1,806,000,000

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Catch-up adjustment included in tax benefit, primarily related to a decrease in forecasted income

33,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discrete tax benefit included in tax benefit, to adjust state deferred taxes

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

13,000,000

Charge included in tax benefit to adjust deferred taxes for prior years' differences between the financial statement carrying amounts of assets and liabilities and their tax bases

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

19,000,000

Gain (loss) on sale of asset

'

'

'

'

'

'

'

'

'

'

'

'

-399,000,000

-399,000,000

-399,000,000

'

'

'

Tax benefit related to adjustments to tax reserves

'

'

20,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Tax benefit related to changes in estimated 2011 federal tax liability

'

'

26,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Income tax receivable

185,000,000

185,000,000

10,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrecognized tax benefits

127,000,000

127,000,000

85,000,000

110,000,000

115,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Total amount of unrecognized tax benefits that, if recognized, would affect effective tax rate

69,000,000

69,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accrued liabilities, interest on unrecognized tax benefits

7,000,000

7,000,000

7,000,000

6,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected decrease in unrecognized tax benefits during the next 12 months

-9,000,000

-9,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Domestic (loss) income before income taxes

'

'

'

'

'

'

-899,000,000

782,000,000

519,000,000

'

'

'

'

'

'

'

'

'

Foreign loss before income taxes

'

'

'

'

'

'

'

'

'

-1,333,000,000

-776,000,000

-492,000,000

'

'

'

'

'

'

Undistributed earnings of certain consolidated foreign subsidiaries

830,000,000

830,000,000

2,700,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deferred tax liability, if earnings were not indefinitely reinvested

280,000,000

280,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net deferred tax (liability) asset

147,000,000

147,000,000

595,000,000

'

'

'

-88,000,000

538,000,000

'

59,000,000

57,000,000

'

'

'

'

'

'

'

Deferred tax asset, valuation allowance

'

'

'

'

'

'

'

'

'

$1,028,000,000

$1,099,000,000

'

'

'

'

'

'

'

Slovak income tax rate

'

'

'

'

'

23.00%

'

'

'

'

'

'

'

'

'

'

22.00%

'

Investments_and_LongTerm_Recei2

Investments and Long-Term Receivables - Schedule of Investments and Long-Term Receivables (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Equity Method Investments and Joint Ventures [Abstract]	'	'
Equity method investments	$558	$570
Receivables due after one year	58	34
Other	5	5
Total	621	609
Investments and long-term receivables, allowance	$3	$3

Investments_and_LongTerm_Recei3

Investments and Long-Term Receivables - Summarized Financial Information of Investees Accounted for by Equity Method of Accounting (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income data:	'	'	'
Net Sales	$3,735	$4,019	$3,514
Operating income	449	650	319
Net income	413	602	264
Balance sheet data:	'	'	'
Current Assets	912	1,028	'
Noncurrent Assets	1,876	1,981	'
Current liabilities	677	569	'
Noncurrent Liabilities	$852	$1,220	'

Investments_and_LongTerm_Recei4

Investments and Long-Term Receivables - Investees Accounted for using Equity Method (Detail)	Dec. 31, 2013
Acero Prime S.R.L. de CV | Mexico	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	40.00%
Apolo Tubulars S.A. | Brazil	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Baycoat Limited Partnership | Canada	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Baycoat Limited | Canada	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Chrome Deposit Corporation | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Daniel Ross Bridge, LLC | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
D.C. Chrome Limited | Canada	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Double Eagle Steel Coating Company | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Double G Coatings Company L.P. | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Feralloy Processing Company | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	49.00%
Hibbing Development Company | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	24.10%
Hibbing Taconite Company | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	14.70%	[1]
Leeds Retail Center LLC | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	38.00%
Patriot Premium Threading Services | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
PRO-TEC Coating Company | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Strategic Investment Fund Partners I | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	8.60%	[2]
Strategic Investment Fund Partners II | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	4.90%	[2]
Swan Point Development Company, Inc. | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Tilden Mining Company, L.C. | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	15.00%	[1]
United Spiral Pipe, LLC | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	35.00%
USS-POSCO Industries | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	50.00%
Worthington Specialty Processing | United States	'
Schedule of Equity Method Investments [Line Items]	'
Investees accounted for using equity method	49.00%
[1]	Hibbing Taconite Company (HTC) is an unincorporated joint venture that is owned, in part, by Hibbing Development Company (HDC), which is accounted for using the equity method. Through HDC we are able to influence the activities of HTC, and as such, its activities are accounted for using the equity method.Tilden Mining Company, L.C. is a limited liability company and in accordance with ASC Topic 323 “Partnerships and Unincorporated Joint Ventures,” (ASC Topic 323) its financial activities are accounted for using the equity method.
[2]	Strategic Investment Fund Partners I and II are limited partnerships and in accordance with ASC Topic 323, the financial activities are accounted for using the equity method.

Investments_and_LongTerm_Recei5

Investments and Long-Term Receivables - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Investments [Line Items]	'	'	'
Income from investees	$40	$144	$85
Dividends and partnership distributions received from equity investees	13	98	31
United Spiral Pipe, LLC	'	'	'
Schedule of Investments [Line Items]	'	'	'
Write-off of equity investment	'	0	0
United States | United Spiral Pipe, LLC	'	'	'
Schedule of Investments [Line Items]	'	'	'
Write-off of equity investment	16	'	'
Non-cash charge to write-off interest receivable	$6	'	'

Property_Plant_and_Equipment_S

Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
In Millions, unless otherwise specified			Buildings	Machinery and Equipment	Machinery and Equipment	Information Technology	Information Technology	Assets Held under Capital Leases	Assets Held under Capital Leases
				Minimum	Maximum	Minimum	Maximum	Minimum	Maximum
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'	'	'	'
Land and depletable property	$251	$264	'	'	'	'	'	'	'
Buildings	1,367	1,394	'	'	'	'	'	'	'
Machinery and equipment	14,386	14,408	'	'	'	'	'	'	'
Information technology	758	709	'	'	'	'	'	'	'
Assets under capital lease	37	131	'	'	'	'	'	'	'
Total	16,799	16,906	'	'	'	'	'	'	'
Less accumulated depreciation and depletion	10,877	10,498	'	'	'	'	'	'	'
Net	$5,922	$6,408	'	'	'	'	'	'	'
Useful Lives (in years)	'	'	'35 years	'4 years	'22 years	'5 years	'6 years	'2 years	'25 years

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional Information (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Property, Plant and Equipment [Abstract]	'	'
Accumulated depreciation and depletion for assets acquired under capital leases (including sale-leasebacks accounted for as financings)	$5	$95

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets - Changes in Carrying Amount of Goodwill by Segment (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Roll Forward]	'	'	'
Goodwill, beginning balance	$1,822	$1,783	'
Goodwill from acquisitions	3	'	'
Impairment	-1,806	0	0
Currency translation	-15	39	'
Goodwill, ending balance	4	1,822	1,783
Flat-rolled Segment	'	'	'
Goodwill [Roll Forward]	'	'	'
Goodwill, beginning balance	984	945	'
Goodwill from acquisitions	0	'	'
Impairment	-969	'	'
Currency translation	-15	39	'
Goodwill, ending balance	0	984	'
USSE Segment	'	'	'
Goodwill [Roll Forward]	'	'	'
Goodwill, beginning balance	4	4	'
Goodwill from acquisitions	0	'	'
Impairment	0	'	'
Currency translation	0	0	'
Goodwill, ending balance	4	4	'
Tubular Segment	'	'	'
Goodwill [Roll Forward]	'	'	'
Goodwill, beginning balance	834	834	'
Goodwill from acquisitions	3	'	'
Impairment	-837	'	'
Currency translation	0	0	'
Goodwill, ending balance	$0	$834	'

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets - Amortizable Intangible Assets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013
In Millions, unless otherwise specified			Customer Relationships	Customer Relationships	Customer Relationships	Customer Relationships	Other Intangible Assets	Other Intangible Assets	Other Intangible Assets	Other Intangible Assets
					Minimum	Maximum			Minimum	Maximum
Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'	'	'	'	'	'
Gross Carrying Amount	$238	$243	$215	$221	'	'	$23	$22	'	'
Accumulated Amortization	75	65	63	54	'	'	12	11	'	'
Net Amount	$163	$178	$152	$167	'	'	$11	$11	'	'
Useful Lives (in years)	'	'	'	'	'22 years	'23 years	'	'	'2 years	'20 years

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets - Additional Information (Detail) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Unit

Flat-rolled Segment

Flat-rolled Segment

Flat-rolled Segment

Tubular Segment

Tubular Segment

Tubular Segment

USSE Segment

USSE Segment

USSE Segment

Use Rights

Developed Technology Rights

Flat Rolled reporting unit

Texas Operations reporting unit

Indefinite-lived Intangible Assets [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of reporting units that have significant amount of goodwill

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Impairment of goodwill

$1,806

$0

$0

$969

'

'

$837

'

'

$0

'

'

'

'

$969

$837

Goodwill

4

1,822

1,783

0

984

945

0

834

834

4

4

4

'

'

'

'

Perpetual growth rate

3.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount rate

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Carrying amount of acquired water rights with indefinite lives

'

75

'

'

'

'

'

'

'

'

'

'

75

'

'

'

Payment for acquisition of indefinite-lived intangible assets

12

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

Purchase price

36

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Indefinite-lived intangible assets acquired

'

'

'

'

'

'

'

'

'

'

'

'

'

33

'

'

Maximum potential liability for contingent consideration

53

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Liability for estimated fair value of contingent consideration

24

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortization expense

10

11

11

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected amortization expense, for 2014

11

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected amortization expense, for 2015

11

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected amortization expense, for 2016

11

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected amortization expense, for 2017

11

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected amortization expense, for 2018

$10

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

StockBased_Compensation_Plans_1

Stock-Based Compensation Plans - Total Stock-Based Compensation Awards Granted (Detail)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]	'		'	'
Restricted Stock Units and Performance Awards, Grants	1,315,380		'	'
Executive Stock Options	'		'	'
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]	'		'	'
Stock Options, Grants	838,610		510,570	228,300
Non-executive Stock Options	'		'	'
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]	'		'	'
Stock Options, Grants	971,860		993,310	478,760
Restricted Stock Units	'		'	'
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]	'		'	'
Restricted Stock Units and Performance Awards, Grants	1,043,420		910,011	422,080
Performance Awards	'		'	'
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]	'		'	'
Restricted Stock Units and Performance Awards, Grants	271,960	[1]	328,780	85,040
[1]	The number of shares shown for the performance awards is based on the target number of share awards.

StockBased_Compensation_Plans_2

Stock-Based Compensation Plans - Total Compensation Expense Recognized for Stock-Based Compensation Awards (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock-based compensation expense recognized:	'	'	'
Stock-based compensation expense recognized	$33	$38	$33
Related deferred income tax benefit	12	14	12
Decrease in net income	21	24	21
Share Based Compensation Expense Per Share, Basic	$0.14	$0.16	$0.14
Share Based Compensation Expense Per Share, Diluted	$0.14	$0.16	$0.14
Cost of sales	'	'	'
Stock-based compensation expense recognized:	'	'	'
Stock-based compensation expense recognized	10	12	10
Selling, general and administrative expenses	'	'	'
Stock-based compensation expense recognized:	'	'	'
Stock-based compensation expense recognized	$23	$26	$23

StockBased_Compensation_Plans_3

Stock-Based Compensation Plans - Black-Scholes Assumptions (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]	'		'		'
Grant date price per share of option award	'		$22.28	[1]	$45.81	[1]
Granted	$21.60		'		'
Expected annual dividends per share	'		$0.20	[1]	$0.20	[1]
Expected life in years	'		'5 years	[1]	'5 years	[1]
Expected volatility	'		68.00%	[1]	64.00%	[1]
Risk-free interest rate	'		0.80%	[1]	1.80%	[1]
Average grant date fair value per share of unvested option awards as calculated from above	'		$11.93	[1]	$24.39	[1]
Executive Grants	'		'		'
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]	'		'		'
Grant date price per share of option award	$18.62	[1]	'		'
Granted	$25.03	[1]	'		'
Expected annual dividends per share	$0.20	[1]	'		'
Expected life in years	'5 years	[1]	'		'
Expected volatility	66.00%	[1]	'		'
Risk-free interest rate	1.30%	[1]	'		'
Average grant date fair value per share of unvested option awards as calculated from above	$8.44	[1]	'		'
Non-Executive Grants	'		'		'
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]	'		'		'
Grant date price per share of option award	$18.64	[1]	'		'
Granted	$18.64	[1]	'		'
Expected annual dividends per share	$0.20	[1]	'		'
Expected life in years	'5 years	[1]	'		'
Expected volatility	67.00%	[1]	'		'
Risk-free interest rate	1.00%	[1]	'		'
Average grant date fair value per share of unvested option awards as calculated from above	$9.70	[1]	'		'
Executive and Non-Executive Stock Options [Member]	'		'		'
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]	'		'		'
Granted	'		$22.28	[1]	$45.81	[1]
[1]	The assumptions represent a weighted-average for all grants during the year.

StockBased_Compensation_Plans_4

Stock-Based Compensation Plans - Status and Activity of Stock Options (Detail) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013
Shares [Roll Forward]	'
Outstanding at beginning of period	4,318,966
Granted	1,810,470
Exercised	-14,383
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$22.31
Forfeited or expired	-907,765
Outstanding at end of period	5,207,288
Exercisable at end of period	2,634,676
Exercisable and expected to vest at end of period	4,946,640
Weighted- Average Exercise Price (per share)	'
Outstanding at beginning of period	$43.86
Granted	$21.60
Forfeited or expired	$35.36
Outstanding at end of period	$37.66
Exercisable at end of period	$51.34
Exercisable and expected to vest at end of a period	$38.42
Weighted- Average Remaining Contractual Term (in years)	'
Outstanding at end of period	'7 years 6 months
Exercisable at end of period	'6 years
Exercisable and expected to vest at end of period	'7 years 4 months 24 days
Aggregate Intrinsic Value	'
Outstanding at end of period	$21
Exercisable at end of period	3
Exercisable and expected to vest at end of period	$20

StockBased_Compensation_Plans_5

Stock-Based Compensation Plans - Performance Awards Outstanding and their Fair Market Value on Respective Grant Date (Detail) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013
Performance Period 2013 to 2016	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Fair Value	$6
Minimum Shares	0
Target Shares	271,960
Maximum Shares	543,920
Performance Period 2012 to 2015	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Fair Value	8
Minimum Shares	0
Target Shares	328,780
Maximum Shares	657,560
Performance Period 2011 to 2014	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Fair Value	$6
Minimum Shares	0
Target Shares	85,040
Maximum Shares	170,080

StockBased_Compensation_Plans_6

Stock-Based Compensation Plans - Status and Activity of Nonvested Stock Awards (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Nonvested Stock Awards [Roll Forward]	'		'		'
Nonvested, beginning of period	1,765,312		'		'
Granted	1,315,380		'		'
Vested	-530,827		'		'
Performance adjustment factor	-89,294	[1]	'		'
Forfeited or expired	-468,337		'		'
Nonvested, end of period	1,992,234		'		'
Weighted- Average Grant-Date Fair Value	'		'		'
Beginning of period	31.62		'		'
Granted	19.2		'		'
Vested	32.58		'		'
Performance adjustment factor	57.02	[1]	'		'
Forfeited or expired	23.34		'		'
End of period	23.97		'		'
Percentage of original grants of awards to targeted amounts	100.00%		'		'
Restricted Stock Units	'		'		'
Nonvested Stock Awards [Roll Forward]	'		'		'
Nonvested, beginning of period	1,262,198		'		'
Granted	1,043,420		910,011		422,080
Vested	-530,827		'		'
Performance adjustment factor	0	[1],[2]	'		'
Forfeited or expired	-282,533		'		'
Nonvested, end of period	1,492,258		1,262,198		'
Performance Awards	'		'		'
Nonvested Stock Awards [Roll Forward]	'		'		'
Nonvested, beginning of period	503,114	[2]	'		'
Granted	271,960	[2]	328,780		85,040
Vested	0		'		'
Performance adjustment factor	-89,294	[1],[2]	'		'
Forfeited or expired	-185,804		'		'
Nonvested, end of period	499,976	[2]	503,114	[2]	'
[1]	Consists of adjustments to vested performance awards to reflect actual performance. The adjustments were required since the original grants of the awards were at 100 percent of the targeted amounts.
[2]	The number of shares shown for the performance awards is based on the target number of share awards.

StockBased_Compensation_Plans_7

Stock-Based Compensation Plans - Restricted Stock Units and Performance Awards Granted (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of awards granted	1,315,380	'	'
Weighted-average grant-date fair value per share	$23.97	$31.62	'
Restricted Stock Units and Performance Stock Units	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of awards granted	1,315,380	1,238,791	507,120
Weighted-average grant-date fair value per share	$19.20	$23.07	$49.10

StockBased_Compensation_Plans_8

Stock-Based Compensation Plans - Stock-Based Compensation Plans - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Unrecognized compensation costs related to nonvested stocks	$35	'	'
Weighted average period for recognizing nonvested stock based compensation costs	'12 months	'	'
Exercise price	$21.60	'	'
Aggregate intrinsic value of options outstanding	21	'	'
Stock options exercised, total intrinsic value	'	'	3
Shares vested, fair value	$17	$16	$15
2005 Stock Incentive Plan	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Aggregate number of shares to be issued	15,450,000	'	'
Number of shares available for future grant	2,609,897	'	'
Reduction in number of shares available under Stock Plan for each share issued under Plan pursuant to award other than stock option	1.64	'	'
Stock Options	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-based compensation plans, vesting period	'3 years	'3 years	'3 years
Share-based compensation plans, term	'10 years	'10 years	'10 years
Premium-Priced Stock Options	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Exercise price	$25	'	'
Restricted Stock Units	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-based compensation plans, vesting period	'3 years	'	'
Performance Awards	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Share-based compensation plans, vesting period	'3 years	'	'
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%	'	'
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%	'	'

Derivative_Instruments_Locatio

Derivative Instruments - Location and Amounts of Fair Values Related to Derivatives in Financial Statements (Detail) (Foreign exchange forward contracts, Accounts payable, USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Foreign exchange forward contracts | Accounts payable	'	'
Derivative [Line Items]	'	'
Foreign exchange forward contracts, fair value	$11	$12

Derivative_Instruments_Locatio1

Derivative Instruments - Location and Amounts of Gains or Losses Related to Derivatives in Financial Statements (Detail) (Foreign exchange forward contracts, Other financial costs, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Foreign exchange forward contracts | Other financial costs	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'
Amount of Gain (Loss)	($14)	($7)	$13

Derivative_Instruments_Additio

Derivative Instruments - Additional Information (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Euro forward sales contracts notional value	$320

Debt_Schedule_of_Debt_Detail

Debt - Schedule of Debt (Detail)

Dec. 31, 2013

Dec. 31, 2012

21-May-07

Dec. 31, 2013

Dec. 31, 2012

21-May-07

Dec. 31, 2013

Dec. 31, 2012

Mar. 15, 2012

Dec. 31, 2013

Mar. 26, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Mar. 16, 2010

Dec. 31, 2013

Dec. 31, 2012

Dec. 10, 2007

Dec. 31, 2013

Dec. 31, 2012

21-May-07

Dec. 31, 2013

Mar. 26, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

4-May-09

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 01, 2010

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

USD ($)

USD ($)

USD ($)

2037 Senior Notes

2037 Senior Notes

2037 Senior Notes

2022 Senior Notes

2022 Senior Notes

2022 Senior Notes

2021 Senior Notes

2021 Senior Notes

2021 Senior Notes

2020 Senior Notes

2020 Senior Notes

2020 Senior Notes

2018 Senior Notes

2018 Senior Notes

2018 Senior Notes

2017 Senior Notes

2017 Senior Notes

2017 Senior Notes

2019 Senior Convertible Notes

2019 Senior Convertible Notes

2019 Senior Convertible Notes

2014 Senior Convertible Notes

2014 Senior Convertible Notes

2014 Senior Convertible Notes

Province Note

Province Note

Province Note

Environmental Revenue Bonds

Environmental Revenue Bonds

Recovery Zone Facility Bonds

Recovery Zone Facility Bonds

Recovery Zone Facility Bonds

Fairfield Caster Lease

Fairfield Caster Lease

Other capital leases and all other obligations

Other capital leases and all other obligations

Amended Credit Agreement

Amended Credit Agreement

USSK Revolver

USSK Revolver

USSK Credit Facilities

USSK Credit Facilities

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

CAD

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest Rates %

'

'

'

6.65%

'

6.65%

7.50%

'

7.50%

6.88%

6.88%

'

7.38%

'

7.38%

7.00%

'

7.00%

6.05%

'

6.05%

2.75%

2.75%

'

4.00%

'

4.00%

1.00%

1.00%

'

5.75%

'

6.75%

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Face Amount

'

'

$1,100,000,000

'

'

$350,000,000

'

'

$400,000,000

'

$275,000,000

'

'

'

$600,000,000

'

'

$500,000,000

'

'

$450,000,000

$316,000,000

$316,000,000

'

'

'

$863,000,000

'

150,000,000

'

'

'

'

'

$70,000,000

'

'

'

'

'

'

'

'

'

'

Interest Rates %, minimum

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.38%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest Rates %, maximum

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.88%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total Debt

4,008,000,000

3,969,000,000

'

350,000,000

350,000,000

'

400,000,000

400,000,000

'

275,000,000

'

0

600,000,000

600,000,000

'

500,000,000

500,000,000

'

450,000,000

450,000,000

'

269,000,000

'

0

322,000,000

863,000,000

'

141,000,000

'

151,000,000

549,000,000

549,000,000

70,000,000

70,000,000

'

35,000,000

35,000,000

0

1,000,000

0

0

0

0

0

0

Less Province Note fair value adjustment

15,000,000

23,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Less unamortized discount

54,000,000

8,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

47,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Less short-term debt and long-term debt due within one year

323,000,000

2,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt

$3,616,000,000

$3,936,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt_Redemption_Price_of_2021_

Debt - Redemption Price of 2021 Senior Notes as Percentage of Principal Amount Plus Accrued and Unpaid Interest to, but Excluding, Redemption Date (Detail) (2021 Senior Notes)	12 Months Ended
	Dec. 31, 2013
2017	'
Debt Instrument [Line Items]	'
Debt Instrument, Redemption Price, Percentage	103.44%
2018	'
Debt Instrument [Line Items]	'
Debt Instrument, Redemption Price, Percentage	101.72%
2019 and thereafter	'
Debt Instrument [Line Items]	'
Debt Instrument, Redemption Price, Percentage	100.00%

Debt_Redemption_Price_of_2022_

Debt - Redemption Price of 2022 Senior Notes as Percentage of Principal Amount Plus Accrued and Unpaid Interest to, but Excluding, Redemption Date (Details) (2022 Senior Notes)	12 Months Ended
	Dec. 31, 2013
2017	'
Debt Instrument, Redemption [Line Items]	'
Debt Instrument, Redemption Price, Percentage	103.75%
2018	'
Debt Instrument, Redemption [Line Items]	'
Debt Instrument, Redemption Price, Percentage	102.50%
2019	'
Debt Instrument, Redemption [Line Items]	'
Debt Instrument, Redemption Price, Percentage	101.25%
2020 and thereafter	'
Debt Instrument, Redemption [Line Items]	'
Debt Instrument, Redemption Price, Percentage	100.00%

Debt_Trade_Receivables_for_Uni

Debt - Trade Receivables for United States Steel Receivables, Limited Liability Company (Detail) (Receivables Purchase Agreement, USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Receivables Purchase Agreement	'	'
Debt Instrument [Line Items]	'	'
Balance of accounts receivable-net, eligible for sale to third-parties	$988	$1,127
Accounts receivable sold to third-parties	0	0
Balance included in Receivables on the balance sheet of U. S. Steel	$988	$1,127

Debt_Aggregate_Maturities_of_D

Debt - Aggregate Maturities of Debt (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Debt Disclosure [Abstract]	'
2014	$323	[1]
2015	189	[1]
2016	45	[1]
2017	500	[1]
2018	503	[1]
Later Years	2,433	[1]
Total	$3,993	[1]
[1]	Debt maturities include the Province Note fair value adjustment discussed above.

Debt_Additional_Information_De

Debt - Additional Information (Detail)

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

1 Months Ended

0 Months Ended

9 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

0 Months Ended

0 Months Ended

0 Months Ended

0 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

21-May-07

Feb. 25, 2014

Dec. 31, 2013

Dec. 31, 2013

Mar. 26, 2013

Dec. 31, 2013

Dec. 31, 2012

4-May-09

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Mar. 26, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Mar. 15, 2012

Dec. 31, 2013

Dec. 31, 2012

Apr. 30, 2012

21-May-07

Mar. 16, 2010

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 10, 2007

Dec. 31, 2013

Dec. 31, 2012

21-May-07

Dec. 31, 2013

Dec. 31, 2012

21-May-07

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Aug. 17, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 01, 2010

Jul. 20, 2011

Dec. 31, 2013

Dec. 31, 2012

Jun. 12, 2009

Feb. 25, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Jul. 15, 2013

Jul. 14, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

USD ($)

USD ($)

USD ($)

USD ($)

Subsequent Event

USSC Plans

Fairfield Caster Lease

2021 Senior Notes

2021 Senior Notes

2021 Senior Notes

2014 Senior Convertible Notes

2014 Senior Convertible Notes

2014 Senior Convertible Notes

2014 Senior Convertible Notes

2019 Senior Convertible Notes

2019 Senior Convertible Notes

2019 Senior Convertible Notes

2019 Senior Convertible Notes

2022 Senior Notes

2022 Senior Notes

2022 Senior Notes

2013 Senior Notes

2013 Senior Notes

2020 Senior Notes

2020 Senior Notes

2020 Senior Notes

2018 Senior Notes

2018 Senior Notes

2018 Senior Notes

2037 Senior Notes

2037 Senior Notes

2037 Senior Notes

2017 Senior Notes

2017 Senior Notes

2017 Senior Notes

Province Note

Province Note

Province Note

Environmental Revenue Bonds

Environmental Revenue Bonds

Environmental Revenue Bonds

Recovery Zone Facility Bonds

Recovery Zone Facility Bonds

Recovery Zone Facility Bonds

Amended Credit Agreement

Amended Credit Agreement

Amended Credit Agreement

Amended Credit Agreement

Amended Credit Agreement

Receivables Purchase Agreement

Receivables Purchase Agreement

USSK Revolver

USSK Revolver

USSK Revolver

USSK Revolver

USSK Revolver

USSK Revolver

USSK Credit Facilities

USSK Credit Facilities

USSK €20 Million Unsecured Credit Facility

USSK €20 Million Unsecured Credit Facility

USSK €20 Million Unsecured Credit Facility

USSK €20 Million Unsecured Credit Facility

USSK €10 Million Unsecured Credit Facility

USSK €10 Million Unsecured Credit Facility

Change in Control Debt Obligations

Change in Control Fairfield Slab Caster

USD ($)

plan

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

CAD

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Subsequent Event

USD ($)

USD ($)

USD ($)

EUR (€)

EUR (€)

EUR (€)

USD ($)

EUR (€)

USD ($)

USD ($)

USD ($)

EUR (€)

USD ($)

EUR (€)

USD ($)

EUR (€)

USD ($)

USD ($)

USD ($)

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt Instrument, Face Amount

'

'

'

$1,100,000,000

'

'

'

$275,000,000

'

'

$863,000,000

'

'

'

$316,000,000

$316,000,000

$316,000,000

'

$400,000,000

'

'

'

$300,000,000

$600,000,000

'

'

'

'

$500,000,000

'

'

$350,000,000

'

'

$450,000,000

'

150,000,000

'

'

'

'

'

'

$70,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stated interest rate

'

'

'

'

'

'

'

6.88%

6.88%

'

4.00%

'

4.00%

'

2.75%

2.75%

2.75%

'

7.50%

7.50%

'

5.65%

5.65%

7.38%

7.38%

'

7.00%

'

7.00%

6.65%

'

6.65%

6.05%

'

6.05%

1.00%

1.00%

'

'

5.75%

'

6.75%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net proceeds from offering

'

'

'

'

'

'

'

270,000,000

'

'

'

'

'

'

306,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Underwriting discount and third party expenses

'

'

'

'

'

'

'

5,000,000

'

'

'

'

'

'

10,000,000

'

'

'

8,000,000

'

'

'

'

13,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion rate (shares per $1,000 of principal)

'

'

'

'

'

'

'

'

'

'

31.3725

'

'

'

'

39.5491

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion price per share

'

'

'

'

'

'

'

'

'

'

$31.88

'

'

'

'

$25.29

$25.29

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares Notes are convertible to

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

12,507,403

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum number of shares that could be issued upon conversion

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

16,259,615

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of repurchase price to current stock price

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt effective interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.20%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.67%

6.67%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Less unamortized discount

54,000,000

8,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

47,000,000

47,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net carrying amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

53,000,000

53,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net proceeds from offering

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

392,000,000

'

'

'

'

582,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Redemption of notes

'

'

'

'

'

'

'

'

'

'

'

542,000,000

'

'

'

'

'

'

'

'

'

300,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Issuance rate, percentage of principal amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

99.13%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Senior Convertible Notes, convertible into number of common stock shares (Based on the initial conversion rate)

'

'

'

'

'

'

'

'

'

'

27,058,781

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Senior Convertible Notes, maximum amount that could be issued upon conversion

'

'

'

'

'

'

'

'

'

'

33,824,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase of Senior Convertible Notes in whole or in part for cash in fundamental change, percentage of principal

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding principal amount

4,008,000,000

3,969,000,000

'

'

'

'

'

'

275,000,000

0

'

'

322,000,000

863,000,000

'

269,000,000

269,000,000

0

'

400,000,000

400,000,000

'

'

'

600,000,000

600,000,000

500,000,000

500,000,000

'

350,000,000

350,000,000

'

450,000,000

450,000,000

'

141,000,000

'

151,000,000

'

549,000,000

549,000,000

70,000,000

70,000,000

'

'

0

0

'

'

'

'

0

'

'

'

0

'

0

0

'

'

'

'

'

'

'

'

Repurchase of notes

'

'

'

'

'

'

'

'

'

'

'

580,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss on repurchase of notes

'

'

'

'

'

'

'

'

'

'

'

34,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt discount rate in solvency deficiencies in Stelco pension plans

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75.00%

75.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of pension plans

'

'

'

'

'

4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceed from issuance of Environmental Revenue Bonds

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

94,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net Proceed from sale of Environmental Revenue Bonds

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

93,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restricted cash

81,000,000

181,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

43,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Lease term after renewal

'

'

'

'

'

'

'9 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument, maximum borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

875,000,000

'

750,000,000

'

'

'

276,000,000

200,000,000

200,000,000

200,000,000

264,000,000

200,000,000

41,000,000

'

27,000,000

20,000,000

26,000,000

20,000,000

14,000,000

10,000,000

'

'

Increase in credit facility availability

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit facility, amount outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

'

'

'

'

0

'

'

'

0

'

'

'

0

'

0

'

0

'

'

'

Minimum fixed charge coverage ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of total aggregate commitments, upper range under financial covenant

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Credit Agreement, upper range of outstanding debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

87,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum liquidity

'

'

'

'

175,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

145,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Receivables Purchase Agreement, maximum amount of receivable eligible for sale

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

625,000,000

625,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Receivables sold to third-party conduits

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Receivables Purchase Agreement Subordinated Retained Interest

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

625,000,000

625,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Receivables Purchase Agreement Availability at Period End

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

572,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Receivables Purchase Agreement Borrowing Capacity Decrease Due To Letters Of Credit Outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

53,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments relating to fees

3,000,000

4,000,000

4,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,000,000

4,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount reinvested from collection of eligible accounts receivable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

1,175,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Available borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

38,000,000

'

'

'

24,000,000

'

'

'

'

'

Customs and other guarantees outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,000,000

'

'

'

2,000,000

'

'

'

'

'

Loss exposure

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$3,212,000,000

$39,000,000

2012_Labor_Agreements_Addition

2012 Labor Agreements - Additional Information (Detail) (USD $)	3 Months Ended
	Sep. 30, 2012	Dec. 31, 2013	Sep. 01, 2012	Sep. 01, 2012	Sep. 01, 2012	Sep. 01, 2012
		Employee	Oct-12	Apr-14	Sep-13	Jan-15
Employee Benefit Plan [Line Items]	'	'	'	'	'	'
Number of employees covered by 2012 labor agreement	'	16,600	'	'	'	'
Labor agreement, lump sum payment to be paid to each active member	'	'	$2,000	$500	'	'
Labor agreement, total cost for lump sum payments	$35,000,000	'	'	'	'	'
Wage increase percentage	'	'	'	'	2.00%	2.50%

Pensions_and_Other_Benefits_De

Pensions and Other Benefits - Details Relating to Pension Benefits and Other Benefits (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Benefits	'	'	'
Change in benefit obligations [Roll Forward]	'	'	'
Benefit obligations, Beginning Balance	$11,347	$10,770	'
Service cost	128	118	111
Interest cost	403	467	511
Plan amendments	0	29	'
Actuarial losses (gains)	-421	848	'
Exchange rate loss (gain)	-234	81	'
Settlements, curtailments and termination benefits	-16	-28	'
Benefits paid	-950	-938	'
Benefit obligations, Ending Balance	10,257	11,347	10,770
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]	'	'	'
Fair value of plan Beginning Balance	8,659	8,353	'
Actual return on plan assets	1,363	945	'
Employer contributions	226	234	'
Exchange rate gain (loss)	-187	56	'
Fair value of plan assets, Ending Balance	9,122	8,659	8,353
Funded status of plans, Ending Balance	-1,135	-2,688	'
Pension Benefits | Change in plan assets	'	'	'
Change in benefit obligations [Roll Forward]	'	'	'
Benefits paid	-939	-929	'
Other Benefits	'	'	'
Change in benefit obligations [Roll Forward]	'	'	'
Benefit obligations, Beginning Balance	3,940	4,186	'
Service cost	27	28	25
Interest cost	141	170	209
Plan amendments	0	-522	'
Actuarial losses (gains)	-420	375	'
Exchange rate loss (gain)	-55	19	'
Settlements, curtailments and termination benefits	0	0	'
Benefits paid	-255	-316	'
Benefit obligations, Ending Balance	3,378	3,940	4,186
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]	'	'	'
Fair value of plan Beginning Balance	1,732	1,473	'
Actual return on plan assets	346	196	'
Employer contributions	10	76	'
Exchange rate gain (loss)	0	0	'
Fair value of plan assets, Ending Balance	1,970	1,732	1,473
Funded status of plans, Ending Balance	-1,408	-2,208	'
Other Benefits | Change in plan assets	'	'	'
Change in benefit obligations [Roll Forward]	'	'	'
Benefits paid	($118)	($13)	'

Pensions_and_Other_Benefits_Am

Pensions and Other Benefits - Amounts Recognized in Accumulated Other Comprehensive Loss (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
Pension Benefits | Prior Service Cost	'
Accumulated Other Comprehensive Income [Roll Forward]	'
Defined Benefit Plan costs in Accumulated Other Comprehensive, beginning balance	$99
Defined Benefit Plan, Amounts that were amortized from Accumulated Other Comprehensive Income (Loss) during the current period	-24
Defined Benefit Plan, Other Activity in Accumulated Other Comprehensive Income (Loss) during the current period	1
Defined Benefit Plan costs in Accumulated Other Comprehensive, ending balance	76
Pension Benefits | Actuarial Losses	'
Accumulated Other Comprehensive Income [Roll Forward]	'
Defined Benefit Plan costs in Accumulated Other Comprehensive, beginning balance	4,656
Defined Benefit Plan, Amounts that were amortized from Accumulated Other Comprehensive Income (Loss) during the current period	-367
Defined Benefit Plan, Other Activity in Accumulated Other Comprehensive Income (Loss) during the current period	-1,165
Defined Benefit Plan costs in Accumulated Other Comprehensive, ending balance	3,124
Other Benefits | Prior Service Cost	'
Accumulated Other Comprehensive Income [Roll Forward]	'
Defined Benefit Plan costs in Accumulated Other Comprehensive, beginning balance	-180
Defined Benefit Plan, Amounts that were amortized from Accumulated Other Comprehensive Income (Loss) during the current period	13
Defined Benefit Plan, Other Activity in Accumulated Other Comprehensive Income (Loss) during the current period	0
Defined Benefit Plan costs in Accumulated Other Comprehensive, ending balance	-167
Other Benefits | Actuarial Losses	'
Accumulated Other Comprehensive Income [Roll Forward]	'
Defined Benefit Plan costs in Accumulated Other Comprehensive, beginning balance	613
Defined Benefit Plan, Amounts that were amortized from Accumulated Other Comprehensive Income (Loss) during the current period	-31
Defined Benefit Plan, Other Activity in Accumulated Other Comprehensive Income (Loss) during the current period	-632
Defined Benefit Plan costs in Accumulated Other Comprehensive, ending balance	($50)

Pensions_and_Other_Benefits_Pe

Pensions and Other Benefits - Pension and Other Benefits Recognized in Balance Sheet (Detail) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Pension and Other Postretirement Benefits Disclosure [Line Items]	'		'
Accumulated other comprehensive loss effects associated with accounting for pensions and other benefits in accordance with ASC Topic 715	$886		$1,568
Pension Benefits	'		'
Pension and Other Postretirement Benefits Disclosure [Line Items]	'		'
Noncurrent assets	23		11
Current liabilities	-298		-245
Noncurrent liabilities	-860		-2,454
Accumulated other comprehensive loss	3,200	[1]	4,755	[1]
Net amount recognized	2,065		2,067
Other Benefits	'		'
Pension and Other Postretirement Benefits Disclosure [Line Items]	'		'
Noncurrent assets	0		0
Current liabilities	-337		-360
Noncurrent liabilities	-1,071		-1,848
Accumulated other comprehensive loss	-217	[1]	433	[1]
Net amount recognized	($1,625)		($1,775)
[1]	Accumulated other comprehensive loss effects associated with accounting for pensions and other benefits in accordance with ASC Topic 715 at December 31, 2013 and December 31, 2012, respectively, are reflected net of tax of $886 million and $1,568 million respectively, on the Statement of Stockholders’ Equity.

Pensions_and_Other_Benefits_In

Pensions and Other Benefits - Information for Pension Plans with Accumulated Benefit Obligation in Excess of Plan Assets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Information for pension plans with an accumulated benefit obligation in excess of plan assets:	'	'
Aggregate accumulated benefit obligations (ABO)	($9,685)	($10,782)
Aggregate projected benefit obligations (PBO)	-10,144	-11,313
Aggregate fair value of plan assets	$8,986	$8,614

Pensions_and_Other_Benefits_De1

Pensions and Other Benefits - Details of Net Periodic Benefit Costs Related to Pension and Other Benefits (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Pension Benefits	'		'		'
Components of net periodic benefit cost:	'		'		'
Service cost	$128		$118		$111
Interest cost	403		467		511
Expected return on plan assets	-611		-614		-623
Amortization - prior service costs	24		22		21
Amortization - actuarial losses	367		352		352
Net periodic benefit cost, excluding below	311		345		372
Multiemployer plans	74	[1]	70	[1]	65	[1]
Settlement, termination and curtailment (gains)/losses	11		-3		6
Net periodic benefit cost	396		412		443
Other Benefits	'		'		'
Components of net periodic benefit cost:	'		'		'
Service cost	27		28		25
Interest cost	141		170		209
Expected return on plan assets	-131		-117		-105
Amortization - prior service costs	-13		11		25
Amortization - actuarial losses	31		8		5
Net periodic benefit cost, excluding below	55		100		159
Multiemployer plans	0	[1]	0	[1]	0	[1]
Settlement, termination and curtailment (gains)/losses	0		0		0
Net periodic benefit cost	$55		$100		$159
[1]	Primarily represents pension expense for the SPT covering USW employees hired from National Steel Corporation and new USW employees hired after May 21, 2003.

Pensions_and_Other_Benefits_Am1

Pensions and Other Benefits - Amounts in Accumulated Other Comprehensive Income Expected to Be Recognized as Components of Net Periodic Benefit Cost (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
Pension Benefits	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Amortization of actuarial loss/(gain)	$282
Amortization of prior service cost	22
Total recognized from accumulated other comprehensive income	304
Other Benefits	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'
Amortization of actuarial loss/(gain)	13
Amortization of prior service cost	-3
Total recognized from accumulated other comprehensive income	($16)

Pensions_and_Other_Benefits_As

Pensions and Other Benefits - Assumptions used to Determine Benefit Obligation and Net Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Actuarial assumptions used to determine benefit obligations at December 31:	'	'	'
Discount rate	4.50%	'	'
Pension Benefits	'	'	'
Actuarial assumptions used to determine net periodic benefit cost for the year ended December 31:	'	'	'
Expected annual return on plan assets	7.75%	'	'
Pension Benefits | United States	'	'	'
Actuarial assumptions used to determine benefit obligations at December 31:	'	'	'
Discount rate	4.50%	3.75%	'
Increase in compensation rate	4.00%	4.00%	'
Actuarial assumptions used to determine net periodic benefit cost for the year ended December 31:	'	'	'
Discount rate	3.75%	4.50%	5.00%
Expected annual return on plan assets	7.75%	7.75%	8.00%
Increase in compensation rate	4.00%	4.00%	4.00%
Pension Benefits | International	'	'	'
Actuarial assumptions used to determine benefit obligations at December 31:	'	'	'
Discount rate	4.50%	3.75%	'
Increase in compensation rate	3.00%	3.00%	'
Actuarial assumptions used to determine net periodic benefit cost for the year ended December 31:	'	'	'
Discount rate	3.75%	4.50%	5.00%
Expected annual return on plan assets	7.25%	7.25%	7.50%
Increase in compensation rate	3.00%	3.00%	3.00%
Other Benefits	'	'	'
Actuarial assumptions used to determine net periodic benefit cost for the year ended December 31:	'	'	'
Expected annual return on plan assets	7.75%	'	'
Other Benefits | United States	'	'	'
Actuarial assumptions used to determine benefit obligations at December 31:	'	'	'
Discount rate	4.50%	3.75%	'
Increase in compensation rate	4.00%	4.00%	'
Actuarial assumptions used to determine net periodic benefit cost for the year ended December 31:	'	'	'
Discount rate	3.75%	4.50%	5.00%
Expected annual return on plan assets	7.75%	7.75%	8.00%
Increase in compensation rate	4.00%	4.00%	4.00%
Other Benefits | International	'	'	'
Actuarial assumptions used to determine benefit obligations at December 31:	'	'	'
Discount rate	4.50%	3.75%	'
Increase in compensation rate	3.00%	3.00%	'
Actuarial assumptions used to determine net periodic benefit cost for the year ended December 31:	'	'	'
Discount rate	3.75%	4.50%	5.00%
Increase in compensation rate	3.00%	3.00%	3.00%

Pensions_and_Other_Benefits_As1

Pensions and Other Benefits - Assumed Health Care Cost Trend Rates (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
United States	'	'
Assumed health care cost trend rates	'	'
Health care cost trend rate assumed for next year	7.00%	7.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	'2018	'2017
Canada	'	'
Assumed health care cost trend rates	'	'
Health care cost trend rate assumed for next year	6.00%	6.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	'2018	'2017

Pensions_and_Other_Benefits_Ef

Pensions and Other Benefits - Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Effect of one-percentage-point increase on expected return on plan assets, incremental (decrease) increase in net periodic pension costs for 2014	($100)
Effect of one-percentage-point increase on discount rate, incremental (decrease) increase in net periodic pension & other benefits costs for 2014	-39
Effect of one-percentage-point increase on discount rate, incremental (decrease) increase in pension & other benefits liabilities at December 31, 2013	-1,191
Effect of one-percentage-point increase on health care cost escalation trend rates, incremental (decrease) increase in other postretirement benefit obligations	191
Effect of one-percentage-point increase on health care cost escalation trend rates, incremental (decrease) increase in service and interest costs components	10
Effect of one-percentage-point decrease on expected return on plan assets, incremental (decrease) increase in net periodic pension costs for 2014	100
Effect of one-percentage-point decrease on discount rate, incremental (decrease) increase in net periodic pension & other benefits costs for 2014	55
Effect of one-percentage-point decrease on discount rate, incremental (decrease) increase in pension & other benefits liabilities at December 31, 2013	1,418
Effect of one-percentage-point decrease on health care cost escalation trend rates, incremental (decrease) increase in other postretirement benefit obligations	-161
Effect of one-percentage-point decrease on health care cost escalation trend rates, incremental (decrease) increase in service and interest costs components	($8)

Pensions_and_Other_Benefits_Pe1

Pensions and Other Benefits - Pension Plan Assets Carried at Fair Value (Detail) (Pension Benefits, USD $)	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
In Millions, unless otherwise specified
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	$9,122		$8,659		$8,353
Interest in Internally Managed Partnership - Fixed Income	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	1,830	[1]	1,688	[2]	'
Interest in Internally Managed Partnership - Equity	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	3,658	[3]	3,491	[4]	'
Interest in Investment Partnerships	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	823	[5]	608	[5]	'
Equity securities - Foreign	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	444	[6]	482	[6]	'
Foreign Government Debt [Member]	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	'		499	[7]	'
Pooled funds	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	540	[8]	312	[8]	'
Productive Land [Member]	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	302		'		'
Private equities	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	306		342		'
Real Estate	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	301		300		'
Other	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	918	[9]	937	[10]	'
Quoted Prices in Active Markets (Level 1)	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	902		985		'
Quoted Prices in Active Markets (Level 1) | Interest in Internally Managed Partnership - Fixed Income	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[1]	0	[1]	'
Quoted Prices in Active Markets (Level 1) | Interest in Internally Managed Partnership - Equity	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[3]	0	[3]	'
Quoted Prices in Active Markets (Level 1) | Interest in Investment Partnerships	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[5]	0	[5]	'
Quoted Prices in Active Markets (Level 1) | Equity securities - Foreign	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	444	[6]	482	[6]	'
Quoted Prices in Active Markets (Level 1) | Foreign Government Debt [Member]	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	'		0	[7]	'
Quoted Prices in Active Markets (Level 1) | Pooled funds	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[8]	0	[8]	'
Quoted Prices in Active Markets (Level 1) | Productive Land [Member]	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0		'		'
Quoted Prices in Active Markets (Level 1) | Private equities	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0		0		'
Quoted Prices in Active Markets (Level 1) | Real Estate	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0		0		'
Quoted Prices in Active Markets (Level 1) | Other	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	458	[9]	503	[10]	'
Significant Observable Inputs (Level 2)	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	7,307		6,791		'
Significant Observable Inputs (Level 2) | Interest in Internally Managed Partnership - Fixed Income	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	1,830	[1]	1,688	[1]	'
Significant Observable Inputs (Level 2) | Interest in Internally Managed Partnership - Equity	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	3,658	[3]	3,491	[3]	'
Significant Observable Inputs (Level 2) | Interest in Investment Partnerships	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	823	[5]	608	[5]	'
Significant Observable Inputs (Level 2) | Equity securities - Foreign	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[6]	0	[6]	'
Significant Observable Inputs (Level 2) | Foreign Government Debt [Member]	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	'		499	[7]	'
Significant Observable Inputs (Level 2) | Pooled funds	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	540	[8]	312	[8]	'
Significant Observable Inputs (Level 2) | Productive Land [Member]	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0		'		'
Significant Observable Inputs (Level 2) | Private equities	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0		0		'
Significant Observable Inputs (Level 2) | Real Estate	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0		0		'
Significant Observable Inputs (Level 2) | Other	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	456	[9]	193	[10]	'
Significant Unobservable Inputs (Level 3)	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	913		883		'
Significant Unobservable Inputs (Level 3) | Interest in Internally Managed Partnership - Fixed Income	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[1]	0	[1]	'
Significant Unobservable Inputs (Level 3) | Interest in Internally Managed Partnership - Equity	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[3]	0	[3]	'
Significant Unobservable Inputs (Level 3) | Interest in Investment Partnerships	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[5]	0	[5]	'
Significant Unobservable Inputs (Level 3) | Equity securities - Foreign	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[6]	0	[6]	'
Significant Unobservable Inputs (Level 3) | Foreign Government Debt [Member]	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	'		0	[7]	'
Significant Unobservable Inputs (Level 3) | Pooled funds	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[8]	0	[8]	'
Significant Unobservable Inputs (Level 3) | Productive Land [Member]	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	302		'		'
Significant Unobservable Inputs (Level 3) | Private equities	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	306		342		'
Significant Unobservable Inputs (Level 3) | Real Estate	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	301		300		'
Significant Unobservable Inputs (Level 3) | Other	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	$4	[9]	$241	[10]	'
[1]	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which United States Steel and Carnegie Pension Fund (UCF) acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:Debt Securities – U.S.$1,127Government Bonds – U.S.629Agency Mortgages65Other9Total$1,830
[2]	(a)UCF Fixed Income Fund LP - a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:Debt Securities – U.S.$1,112Government Bonds – U.S.473Agency Mortgages85Other18Total$1,688
[3]	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:Equity Securities – U.S.$3,346Equity Securities – Foreign181Investment sales receivable130Other1Total$3,658
[4]	UCF Equity Fund LP - a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:Equity Securities – U.S.$3,166Equity Securities – Foreign149Investment sales receivable111Other65Total$3,491
[5]	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
[6]	Includes investments held in a diversified portfolio of Canadian equity securities with no single sector representing more than 30 percent of the portfolio by value.
[7]	Includes investments in Canadian National and Provincial government bonds.
[8]	Investments in funds incorporated in Canada that invest in diversified portfolios of global debt and equity securities.
[9]	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes interests in investment trusts, exchange-traded funds, equity securities – U.S., short-term investments, government bonds - foreign, debt securities – foreign, mineral interests and miscellaneous receivables and payables.
[10]	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes interests in investment trusts, exchange-traded funds, short-term investments, government bonds – U.S., debt securities – U.S., debt securities – foreign, timberlands, mineral interests and miscellaneous receivables and payables.

Pensions_and_Other_Benefits_Pe2

Pensions and Other Benefits - Pension Plan Assets Carried at Fair Value (Parenthetical) (Detail) (Pension Benefits, USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

In Millions, unless otherwise specified

Equity securities - Foreign

Equity securities - Foreign

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Maximum

Maximum

Minimum

Minimum

Debt securities - U. S.

Debt securities - U. S.

Government Bonds - US

Government Bonds - US

Agency Mortgages

Agency Mortgages

Other securities

Other securities

Equity securities - U.S.

Equity securities - U.S.

Equity securities - Foreign

Equity securities - Foreign

Investment Sales Receivable

Investment Sales Receivable

Other securities

Other securities

Canadian Equity Securities

Canadian Equity Securities

Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]

'

'

'

'

'

'

'

'

'

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'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Plan assets carried at fair value

$9,122

$8,659

$8,353

$444

[1]

$482

[1]

$1,830

$1,688

$1,127

$1,112

$629

$473

$65

$85

$9

$18

$3,658

$3,491

$3,346

$3,166

$181

$149

$130

$111

$1

$65

'

'

'

'

Percentage of equity securities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30.00%

30.00%

'

'

Threshold percentage of investments for separate disclosure

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3.00%

3.00%

[1]

Includes investments held in a diversified portfolio of Canadian equity securities with no single sector representing more than 30 percent of the portfolio by value.

Pensions_and_Other_Benefits_Ch

Pensions and Other Benefits - Changes in Fair Value of Pension Plan Level 3 Assets (Detail) (Pension Benefits, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits	'	'
Pension Plan Assets [Roll Forward]	'	'
Balance at beginning of period	$883	$850
Transfers in and/or out of level 3	0	0
Actual return on plan assets:	'	'
Realized gain	89	69
Net unrealized gain	45	8
Purchases, sales, issuances and settlements:	'	'
Purchases	102	98
Sales	-206	-142
Balance at end of period	$913	$883

Pensions_and_Other_Benefits_Ot

Pensions and Other Benefits - Other Benefits Plan Assets Carried at Fair Value (Detail) (Other Benefits, USD $)	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
In Millions, unless otherwise specified
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	$1,970		$1,732		$1,473
Interest in Internally Managed Partnership - Fixed Income	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	513	[1]	468	[2]	'
Interest in Internally Managed Partnership - Equity	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	1,190	[3]	1,061	[4]	'
Interest in Investment Partnerships	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	131	[5]	94	[5]	'
Other	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	136	[6]	109	[6]	'
Quoted Prices in Active Markets (Level 1)	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	37		38		'
Quoted Prices in Active Markets (Level 1) | Interest in Internally Managed Partnership - Fixed Income	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[1]	0	[1]	'
Quoted Prices in Active Markets (Level 1) | Interest in Internally Managed Partnership - Equity	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[3]	0	[3]	'
Quoted Prices in Active Markets (Level 1) | Interest in Investment Partnerships	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[5]	0	[5]	'
Quoted Prices in Active Markets (Level 1) | Other	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	37	[6]	38	[6]	'
Significant Observable Inputs (Level 2)	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	1,834		1,623		'
Significant Observable Inputs (Level 2) | Interest in Internally Managed Partnership - Fixed Income	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	513	[1]	468	[1]	'
Significant Observable Inputs (Level 2) | Interest in Internally Managed Partnership - Equity	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	1,190	[3]	1,061	[3]	'
Significant Observable Inputs (Level 2) | Interest in Investment Partnerships	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	131	[5]	94	[5]	'
Significant Observable Inputs (Level 2) | Other	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[6]	0	[6]	'
Significant Unobservable Inputs (Level 3)	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	99		71		'
Significant Unobservable Inputs (Level 3) | Interest in Internally Managed Partnership - Fixed Income	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[1]	0	[1]	'
Significant Unobservable Inputs (Level 3) | Interest in Internally Managed Partnership - Equity	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[3]	0	[3]	'
Significant Unobservable Inputs (Level 3) | Interest in Investment Partnerships	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	0	[5]	0	[5]	'
Significant Unobservable Inputs (Level 3) | Other	'		'		'
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]	'		'		'
Plan assets carried at fair value	$99	[6]	$71	[6]	'
[1]	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:Debt Securities – U.S.$308Government Bonds – U.S.172Agency Mortgages18Partner contribution receivable 19Other(4)Total$513
[2]	UCF Fixed Income Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:Debt Securities – U.S.$308Government Bonds – U.S.131Agency Mortgages24Other5Total$468
[3]	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:Equity Securities – U.S.$1,081Equity Securities – Foreign59Exchange-traded funds42Other8Total$1,190
[4]	UCF Equity Fund LP – a Delaware limited partnership that offers interests to employee benefit plans for which UCF acts as trustee, investment advisor and/or investment manager. Looking through the limited partnership, the plan’s holdings are as follows:Equity Securities – U.S.$950Equity Securities – Foreign45Investment sales receivable33Other33Total$1,061
[5]	Private investment partnerships whose investment objectives are to achieve long-term capital appreciation by investing in global equity markets.
[6]	Asset categories that are greater than 3% of investments at fair value are disclosed separately. All Other includes short-term investments, exchange-traded funds, private equities, real estate, timberlands and miscellaneous receivables and payables.

Pensions_and_Other_Benefits_Ot1

Pensions and Other Benefits - Other Benefits Plan Assets Carried at Fair Value (Parenthetical) (Detail) (Other Benefits, USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

In Millions, unless otherwise specified

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Debt securities - U. S.

Debt securities - U. S.

Equity securities - U.S.

Equity securities - U.S.

Equity securities - Foreign

Equity securities - Foreign

Government Bonds - US

Government Bonds - US

Agency Mortgages

Agency Mortgages

Partner Contribution Receivable [Member]

Investment Sales Receivable

Other securities

Other securities

Other securities

Other securities

Minimum

Minimum

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Fixed Income

Interest in Internally Managed Partnership - Equity

Interest in Internally Managed Partnership - Equity

Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Plan assets carried at fair value

$1,970

$1,732

$1,473

$513

$468

$1,190

$1,061

$308

$308

$1,081

$950

$59

$45

$172

$131

$18

$24

$19

$42

($4)

$5

$8

$33

'

'

Threshold percentage of investments for separate disclosure

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3.00%

3.00%

Pensions_and_Other_Benefits_Ch1

Pensions and Other Benefits - Changes in Fair Value of Other Benefits Plan Level 3 Assets (Detail) (Other Benefits, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Other Benefits	'	'
Other Benefit Plan Assets [Roll Forward]	'	'
Balance at beginning of period	$71	$57
Transfers in and/or out of level 3	0	0
Actual return on plan assets:	'	'
Realized gain	8	2
Net unrealized gain	6	3
Purchases, sales, issuances and settlements:	'	'
Purchases	29	17
Sales	-15	-8
Balance at end of period	$99	$71

Pensions_and_Other_Benefits_Mu

Pensions and Other Benefits - Multiemployer Pension Plans (Detail) (Steelworkers Pension Trust, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Steelworkers Pension Trust	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Employer Identification Number/Pension Plan Number	'23-6648508/499		'		'
Pension Protection Act Zone Status	'Green	[1]	'Green	[1]	'
FIP/RP Status Pending/Implemented	'No	[2]	'		'
U.S. Steel Contributions	$74		$69		$63
Surcharged Imposed	'No	[3]	'No	[3]	'
Expiration Date of Collective Bargaining Agreement	1-Sep-15		'		'
[1]	The zone status is based on information that U. S. Steel received from the plan and is certified by the plan’s actuary. Among other factors, plans in the green zone are at least 80 percent funded, while plans in the yellow zone are less than 80 percent funded and plans in the red zone are less than 65 percent funded.
[2]	Indicates if a financial improvement plan (FIP) or a rehabilitation plan (RP) is either pending or has been implemented.
[3]	Indicates whether there were charges to U. S. Steel from the plan.

Pensions_and_Other_Benefits_Mu1

Pensions and Other Benefits - Multiemployer Pension Plans (Parenthetical) (Detail) (Steelworkers Pension Trust)	Dec. 31, 2013
Minimum | Green Zone	'
Defined Benefit Plan Disclosure [Line Items]	'
Percentage of plans funded	80.00%
Maximum | Yellow Zone	'
Defined Benefit Plan Disclosure [Line Items]	'
Percentage of plans funded	80.00%
Maximum | Red Zone	'
Defined Benefit Plan Disclosure [Line Items]	'
Percentage of plans funded	65.00%

Pensions_and_Other_Benefits_Be

Pensions and Other Benefits - Benefit Payments Expected to be Paid from Defined Benefit Plans (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Pension Benefits	'
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]	'
2014	$955
2015	808
2016	796
2017	789
2018	771
Years 2019 - 2023	3,563
Other Benefits	'
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]	'
2014	266
2015	285
2016	280
2017	241
2018	232
Years 2019 - 2023	$1,077

Additional_Information_Detail

- Additional Information (Detail)

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Nov. 30, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2007

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

USD ($)

USD ($)

Maximum

Profit Sharing Payments

Pension Benefits

Pension Benefits

Pension Benefits

Pension Benefits

Other Benefits

Other Benefits

Other Benefits

Steelworkers Pension Trust

Steelworkers Pension Trust

Steelworkers Pension Trust

Steelworkers Pension Trust

Steelworkers Pension Trust

Main Defined Benefit Pension Plan

Main Defined Benefit Pension Plan

USSC Plans

USSC Plans

USSC Plans

Change in Assumptions for Pension Plans [Member]

Unfunded Defined Benefit Pension Plans

Unfunded Defined Benefit Pension Plans

Unfunded Other Postretirement Benefit Plans

Unfunded Other Postretirement Benefit Plans

Retiree Health Care and Life Insurance Trust

Defined Contribution

Defined Contribution

Defined Contribution

Defined Contribution Pension Matching Contribution

Defined Contribution Pension Matching Contribution

Defined Contribution Pension Matching Contribution

Canadian Hourly Employees Savings Match

Canadian Hourly Employees Savings Match

Canadian Hourly Employees Savings Match

Supplemental Thrift Plan

Supplemental Thrift Plan

Supplemental Thrift Plan

Other Postemployment Benefit

Other Postemployment Benefit

Equity Funds [Member]

Equity Funds [Member]

Equity Funds [Member]

Equity Funds [Member]

Equity Investment And Loan Receivable [Member]

Equity Investment And Loan Receivable [Member]

Equity Investment And Loan Receivable [Member]

USD ($)

USD ($)

USD ($)

CAD

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Minimum

Minimum

Minimum

USD ($)

USD ($)

USD ($)

CAD

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Pension Benefits

Pension Benefits

Other Benefits

Other Benefits

Equity Funds [Member]

Equity Funds [Member]

Equity Funds [Member]

plan

plan

USD ($)

USD ($)

USD ($)

USD ($)

Pension Benefits

Pension Benefits

Other Benefits

USD ($)

USD ($)

USD ($)

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Defined Benefit Plan, Fair Value of Plan Assets

'

'

'

'

$9,122

'

$8,659

$8,353

$1,970

$1,732

$1,473

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$3,658

$3,491

$1,190

$1,061

$130

$111

$33

Percentage of employees covered by Steelworkers Pension Trust (SPT)

60.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Defined benefit pension plan accumulated benefit obligation

9,798

10,817

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other benefit expense, profit-based payments

'

'

'

40

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Defined Benefit Plan Expected Net Periodic Benefit Cost

'

'

'

'

330

'

'

'

15

'

'

78

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount rate used to measure Pension and Other Benefits obligations

4.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4.50%

4.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Assumed mortality improvement, number of years from the date of liability measurement

'7 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Target allocation for plan assets of equities

'

'

'

'

60.00%

60.00%

'

'

70.00%

'

'

'

'

'

'

'

'

'

65.00%

65.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Assumed rate of return

'

'

'

'

7.75%

7.75%

'

'

7.75%

'

'

'

'

'

'

'

'

'

7.25%

7.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fixed dollar amount that U.S. Steel contributed to SPT plan for each hour participants worked

'

'

'

'

'

'

'

'

'

'

'

2.65

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of U.S. Steel's contribution to SPT plan as to total combined contribution

'

'

'

'

'

'

'

'

'

'

'

'

'

5.00%

5.00%

5.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Investment losses, amortization period

'

'

'

'

'

'

'

'

'

'

'

'29 years

'15 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Employer contributions, defined benefit plans

'

'

'

'

226

'

234

'

10

76

'

'

'

'

'

'

140

140

82

'

94

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Employer contributions, pension plans

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30

20

137

303

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contribution to a restricted account within trust for represented retiree health care and life insurance benefits

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Defined Benefit Plan Deferred Contributions By Employer

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Required contribution - 2014

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of pension plans

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4

4

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Required contribution - 2015

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum required contribution - 2014

'

'

'

'

67

70

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum required contribution - 2015

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

67

70

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Employees currently covered by Defined Contribution Plans

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

66.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Defined contribution plan cost

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

19

17

15

23

21

20

3

3

2

2

1

2

'

'

'

'

'

'

'

'

'

Accrued obligation benefits to former or inactive employees after employment but before retirement

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

122

102

'

'

'

'

'

'

'

APBO amounts, discount rate

4.50%

3.75%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Projected future net periodic benefit costs - 2014

16

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Projected net periodic benefit costs

13

12

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrecognized actuarial gains that will be recorded against AOCI

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

Additional contributions to defined benefit plans

'

'

300

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated future voluntary contributions - 2014

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

140

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated future voluntary contributions - 2015

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

140

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated future voluntary contributions - 2016

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

140

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$350

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Changes_in_Carrying_Values_of_

Changes in Carrying Values of Asset Retirement Obligations (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Asset Retirement Obligations [Roll Forward]	'	'
Balance at beginning of year	$33	$38
Additional obligations incurred	28	2
Obligations settled	-7	-9
Accretion expense	5	2
Balance at end of period	$59	$33

Financial_Assets_and_Liabiliti

Financial Assets and Liabilities Not Carried at Fair Value (Detail) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Financial assets:	'		'
Investments and long-term receivables	$621		$609
Financial liabilities:	'		'
Debt	3,993	[1]	'
Fair Value	'		'
Financial assets:	'		'
Investments and long-term receivables	63	[2]	39	[2]
Financial liabilities:	'		'
Debt	4,198	[3]	4,113	[3]
Carrying Amount	'		'
Financial assets:	'		'
Investments and long-term receivables	63	[2]	39	[2]
Financial liabilities:	'		'
Debt	$3,904	[3]	$3,902	[3]
[1]	Debt maturities include the Province Note fair value adjustment discussed above.
[2]	Excludes equity method investments.
[3]	Excludes borrowings under the RPA and capital lease obligations.

Reclassifications_from_Accumul2

Reclassifications from Accumulated Other Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Income (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	$1,272	[1]	($164)	[1]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	244	[1]	263	[1],[2]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]	'		'
Balance, beginning of period	-3,268	[1]	-3,367	[1]
Net current-period other comprehensive income	1,516	[1]	99	[1]
Balance, end of period	-1,752	[1]	-3,268	[1]
Pension and Other Benefit Items	'		'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	1,220	[1]	-278	[1]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	266	[1],[2]	263	[1],[2]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]	'		'
Balance, beginning of period	-3,613	[1]	-3,598	[1]
Net current-period other comprehensive income	1,486	[1]	-15	[1]
Balance, end of period	-2,127	[1]	-3,613	[1]
Foreign Currency Items	'		'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'		'
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	52	[1]	114	[1]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	-22	[1],[3]	0	[1],[2]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]	'		'
Balance, beginning of period	345	[1]	231	[1]
Net current-period other comprehensive income	30	[1]	114	[1]
Balance, end of period	$375	[1]	$345	[1]
[1]	All amounts are net of tax. Amounts in parentheses indicate debits.
[2]	See table below for further details.
[3]	Included in Income tax (benefit) provision line on the Consolidated Statement of Operations

Reclassifications_from_Accumul3

Reclassifications from Accumulated Other Comprehensive Income - Detail of Amounts Reclassified From Accumulated Other Comprehensive Income (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'		'		'
(Loss) income before income taxes and noncontrolling interests	($2,232,000,000)		$6,000,000		$27,000,000
Tax benefit	560,000,000		-131,000,000		-80,000,000
Net loss	-1,672,000,000		-125,000,000		-53,000,000
Pension and Other Benefit Items | Reclassification out of Accumulated Other Comprehensive Income	'		'		'
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]	'		'		'
Prior service costs	-11,000,000	[1],[2]	-33,000,000	[1],[2]	'
Actuarial gains/(losses)	-398,000,000	[1],[2]	-360,000,000	[1],[2]	'
(Loss) income before income taxes and noncontrolling interests	-409,000,000	[1]	-393,000,000	[1]	'
Tax benefit	143,000,000	[1]	130,000,000	[1]	'
Net loss	($266,000,000)	[1]	($263,000,000)	[1]	'
[1]	Amounts in parentheses indicate debits to income/loss.
[2]	These AOCI components are included in the computation of net periodic benefit cost (see Note 16 for additional details).

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Net cash used in operating activities included:	'		'		'
Interest and other financial costs paid (net of amount capitalized)	($238)		($239)		($222)
Income taxes (paid) refunded	-20		-71		13
Non-cash investing and financing activities:	'		'		'
Change in accrued capital expenditures	-14	[1]	-52	[1]	'
Assets acquired under capital lease	0		35		0
U. S. Steel common stock issued for employee stock plans	$0		$2		$0
[1]	The change in accrued capital expenditures was insignificant for the year ended December 31, 2011.

Transactions_with_Related_Part1

Transactions with Related Parties - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]	'	'	'
Related party sales and service transactions	$1,155	$1,303	$1,258
Accounts payable to related parties	73	78	'
Outside processing services	'	'	'
Related Party Transaction [Line Items]	'	'	'
Purchases from related parties	67	58	54
Taconite pellets	'	'	'
Related Party Transaction [Line Items]	'	'	'
Purchases from related parties	246	298	215
PRO-TEC Coating Company	'	'	'
Related Party Transaction [Line Items]	'	'	'
Accounts payable to related parties	70	75	'
Other Related Parties [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Accounts payable to related parties	$3	$3	'

Future_Minimum_Commitments_for

Future Minimum Commitments for Capital Leases and Operating Leases (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Capital Leases	'
Capital leases future minimum payment in 2014	$5
Capital leases future minimum payment in 2015	5
Capital leases future minimum payment in 2016	5
Capital leases future minimum payment in 2017	5
Capital leases future minimum payment in 2018	5
Capital leases future minimum payment, later years	26
Capital leases sublease rentals	0
Total minimum lease payments	51
Less imputed interest costs	16
Present value of net minimum lease payments included in long-term debt (see Note 14)	35
Operating Leases	'
Operating leases future minimum payment in 2013	76
Operating leases future minimum payment in 2014	71
Operating leases future minimum payment in 2015	63
Operating leases future minimum payment in 2016	45
Operating leases future minimum payment in 2017	14
Operating leases future minimum payment, later years	31
Operating leases sublease rentals	0
Total minimum lease payments	$300

Operating_Lease_Rental_Expense

Operating Lease Rental Expense (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Leases [Abstract]	'	'	'
Minimum rentals	$111	$91	$95
Contingent rentals	11	12	11
Sublease rentals	'	'	0
Net rental expense	$122	$103	$106

Restructuring_and_Other_Charge2

Restructuring and Other Charges - Activity in Accrued Balances for Restructuring and Other Cost Reduction Programs (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
	Employee
Restructuring Reserve [Roll Forward]	'		'	'
Balance at beginning of period	$0		'	'
Additional charges	248		0	0
Balance at end of period	22		0	'
Severance benefits and associated pension curtailment charges	4		'	'
Approximate number of employees terminated	180		'	'
Severance Accrual	'		'	'
Restructuring Reserve [Roll Forward]	'		'	'
Balance at beginning of period	0		'	'
Additional charges	16	[1]	'	'
Cash payments/utilization	0		'	'
Other adjustments and re-classes	0		'	'
Balance at end of period	16		'	'
Exit Costs	'		'	'
Restructuring Reserve [Roll Forward]	'		'	'
Balance at beginning of period	0		'	'
Additional charges	6	[2]	'	'
Cash payments/utilization	0		'	'
Other adjustments and re-classes	0		'	'
Balance at end of period	6		'	'
Accelerated Depreciation	'		'	'
Restructuring Reserve [Roll Forward]	'		'	'
Balance at beginning of period	0		'	'
Additional charges	222	[3]	'	'
Cash payments/utilization	-222		'	'
Other adjustments and re-classes	0		'	'
Balance at end of period	$0		'	'
[1]	Amount relates to charges recognized for severance benefits for approximately 180 employees terminated at Hamilton Works and Lake Erie Works and excludes associated pension curtailment charges of approximately $4 million (see Note 16).
[2]	Amount relates to exit costs associated with the closure of the WGN.
[3]	Accelerated depreciation charges are related to the closure of the iron and steelmaking facilities at Hamilton Works and assets related to WGN.

Restructuring_and_Other_Charge3

Restructuring and Other Charges - Balance Sheet Location of Accrued Liabilities for Restructuring and Other Cost Reduction Programs (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Restructuring Cost and Reserve [Line Items]	'	'
Total	$22	$0
Accounts payable	'	'
Restructuring Cost and Reserve [Line Items]	'	'
Restructuring reserve, current	6	0
Payroll and benefits payable	'	'
Restructuring Cost and Reserve [Line Items]	'	'
Restructuring reserve, current	8	0
Employee benefits	'	'
Restructuring Cost and Reserve [Line Items]	'	'
Restructuring reserve, noncurrent	$8	$0

Contingencies_and_Commitments_1

Contingencies and Commitments - Changes in Accrued Liabilities for Remediation Activities (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Change in Accrued Liabilities for Remediation Activities [Roll Forward]	'	'
Beginning of period	$203	$206
Accruals for environmental remediation deemed probable and reasonably estimable	45	13
Payments	-15	-16
End of period	$233	$203

Contingencies_and_Commitments_2

Contingencies and Commitments - Accrued Liabilities for Remediation Activities Included in Balance Sheet (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Line Items]	'	'	'
Accounts payable, Deferred credits and other non-current liabilities	$233	$203	$206
Accounts payable	'	'	'
Commitments and Contingencies Disclosure [Line Items]	'	'	'
Accounts payable, Deferred credits and other non-current liabilities	17	21	'
Deferred credits and other noncurrent liabilities	'	'	'
Commitments and Contingencies Disclosure [Line Items]	'	'	'
Accounts payable, Deferred credits and other non-current liabilities	$216	$182	'

Contingencies_and_Commitments_3

Contingencies and Commitments - Payments for Contracts with Remaining Terms in Excess of One Year (Detail) (USD $)	Dec. 31, 2013
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
2014	$854
2015	644
2016	411
2017	326
2018	296
Later Years	1,443
Total	$3,974

Contingencies_and_Commitments_4

Contingencies and Commitments - Additional Information (Detail)

0 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

In Millions, unless otherwise specified

Aug. 02, 2012

Jan. 30, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

phase

Allowances

USD ($)

USD ($)

USD ($)

Randle Reef

Randle Reef

National Government

National Government

Provincial Government

Provincial Government

Local Sources

Local Sources

U. S. Steel Canada Inc.

U. S. Steel Canada Inc.

Minimum

Minimum

Maximum

Maximum

Asbestos Matters

Asbestos Matters

Asbestos Matters

Asbestos Matters

Asbestos Matters

Projects with Ongoing Study and Scope Development

Projects with Ongoing Study and Scope Development

Projects with Ongoing Study and Scope Development

Projects with Ongoing Study and Scope Development

Projects with Ongoing Study and Scope Development

Gary Works, Project with Defined Scope

Other Project with Defined Scope Greater Than or Equal to $5 Million

Geneva Project

St Louis Estuary Project

SWMU Project at UPI, Project with Defined Scope

Environmental Remediation Other Projects

Environmental Remediation Other Projects

Environmental Remediation Other Projects

Environmental Remediation Projects Less Than One Million

Environmental Remediation Projects Less Than One Million

Antitrust Class Actions

Surety Bonds

Restricted Cash To Fund Certain Capital Projects

Facility

boiler

USD ($)

CAD

Randle Reef

Randle Reef

Randle Reef

Randle Reef

Randle Reef

Randle Reef

Randle Reef

Randle Reef

USD ($)

Gateway Energy and Coke Company, LLC

USD ($)

Gateway Energy and Coke Company, LLC

USD ($)

USD ($)

Allege Suffering from Mesothelioma

Minimum

Maximum

USD ($)

Resource Conservation and Recovery Act (RCRA) Programs

Voluntary Remediation Program

Minimum

Maximum

USD ($)

Minimum

USD ($)

USD ($)

USD ($)

USD ($)

Minimum

Maximum

USD ($)

Maximum

Facility

USD ($)

USD ($)

T

USD ($)

CAD

USD ($)

CAD

USD ($)

CAD

USD ($)

CAD

Plaintiff

Plaintiff

Plaintiff

Defendant

Defendant

Facility

Facility

Project

USD ($)

USD ($)

USD ($)

Facility

USD ($)

USD ($)

USD ($)

Micron

T

Claim_Group

Claim_Group

non_GHG_pollutant

Loss Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Active cases brought against U.S. Steel

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

720

790

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of plaintiffs involved

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,320

3,330

270

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of defendants involved

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

50

100

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8

'

'

Number of claims pending in jurisdictions

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,560

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of claims pending in jurisdictions

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

77.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payment in settlement of claims

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$11

$15

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cases resolved upon payment

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

250

190

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of cases added and resulted in claims

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

240

285

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of facilities that failed to meet certain environmental requirements

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expenses related to remediation included in cost of sales

'

'

45

13

36

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

32

7

'

'

'

'

'

'

'

'

Projected percentage remediation costs may exceed accrued liabilities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10.00%

'

25.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Environmental remediation projects

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5

4

1

'

'

'

'

'

'

'

6

'

'

'

'

'

'

'

Accrued liabilities for remediation activities

'

'

233

203

206

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

54

5

64

52

7

13

1

5

7

1

'

'

'

Environment exit costs, possible additional loss

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

25

40

'

'

'

'

'

'

'

'

'

'

'

'

'

Accrued liabilities for post-closure site monitoring and other costs

'

'

28

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accrued liability for administrative and legal costs

'

'

6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital expenditures

'

'

64

53

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Overall Goal for Reduction in Emissions, Percent, by 2020

'

'

21.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percent reduction in free allocation of emissions

'

'

12.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Final Allocation for Emissions Allowances During NAP III period

'

48,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated Shortfall in Emissions Allowances During NAP III period

'

14,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Threshold for new PSD requirements, project significantly increases emissions, number of non-GHG pollutants

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum annual emission of new sources subject to PSD and Title V requirement

'

'

100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

NAAQS micron particulate matter in revision process

'

'

2.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated capital expenditures of complying with BAT over 2013 to 2016 period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

200

'

250

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of boilers to be reconstructed for environmental compliance

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of new boilers to be built for environmental compliance

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated Capital Expenditures For Project, Boiler

'

'

150

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Financial assurance guarantees, maximum

'

'

29

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

166

'

Guarantor obligation, recorded liability

'

'

22

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Pretax charge to record liability related to guaranty of debt related to unconsolidated equity investment

'

'

22

[1]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of phases of fact discovery

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Regulatory agencies estimate expenditures amount

'

'

'

'

'

113

120

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contributions committed by third parties

'

'

'

'

'

'

'

38

40

'

'

38

40

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contributions committed by company, hot rolled steel, in tons

'

'

'

'

'

'

'

'

'

'

'

'

'

11,000

11,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contributions committed by company

'

'

'

'

'

'

'

'

'

'

'

'

'

2

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contributions made by company

'

'

'

'

'

'

'

'

'

'

'

'

'

2

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Liability accrued related to committed contributions

'

'

'

'

'

'

'

'

'

'

'

'

'

8

8

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Residual value of equipment

'

'

15

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restricted cash

'

'

81

181

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

43

Restricted cash current

'

'

'

5

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contract commitments to acquire property, plant and equipment

'

'

151

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unconditional purchase obligation term

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'2 years

'

'15 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of purchase obligation

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

90.00%

'

105.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum default payment on termination of agreement

'

'

250

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total payment under take-or-pay contracts

'

'

750

730

740

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Committed Contribution

'

'

'

'

'

'

'

'

'

$38

40

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[1]

Consists primarily of a charge of $22 million in 2013 related to a guarantee of an unconsolidated equity investment for which payment by U. S. Steel is probable (see Note 24).

Valuation_and_Qualifying_Accou

Valuation and Qualifying Accounts and Reserves (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
Allowance for doubtful accounts	'	'		'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'		'
Balance at Beginning of Period	$55	$64		$48
Additions, Charged to Costs and Expenses	5	0		3
Additions, Charged to Other Accounts	0	0		13
Deductions, Charged to Costs and Expenses	0	1		0
Deductions, Charged to Other Accounts	7	8		0
Balance at End of Period	53	55		64
Investments and long-term receivables reserve	'	'		'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'		'
Balance at Beginning of Period	3	3		22
Additions, Charged to Costs and Expenses	0	0		0
Additions, Charged to Other Accounts	7	0		0
Deductions, Charged to Costs and Expenses	0	0		0
Deductions, Charged to Other Accounts	0	0		19
Balance at End of Period	10	3		3
Deferred tax valuation allowance, State	'	'		'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'		'
Balance at Beginning of Period	0	0		5
Additions, Charged to Costs and Expenses	0	0		0
Additions, Charged to Other Accounts	0	0		0
Deductions, Charged to Costs and Expenses	0	0		0
Deductions, Charged to Other Accounts	0	0		5
Balance at End of Period	0	0		0
Deferred tax valuation allowance, Foreign	'	'		'
Movement in Valuation Allowances and Reserves [Roll Forward]	'	'		'
Balance at Beginning of Period	1,099	1,018		870
Additions, Charged to Costs and Expenses	0	47		48
Additions, Charged to Other Accounts	142	169		119
Deductions, Charged to Costs and Expenses	142	0		0
Deductions, Charged to Other Accounts	71	135	[1]	19
Balance at End of Period	$1,028	$1,099		$1,018
[1]	The deferred tax asset valuation allowance for U. S. Steel Serbia was removed as a result of the sale of U. S. Steel Serbia on January 31, 2012.