$CLF
CLEVELAND-CLIFFS INC. Stock $clf

$clf Overview Financials Valuation SEC Filings Company Website

2020 Q2 Form 10-Q Financial Statement

#000076406520000212 Filed on July 30, 2020

Income Statement

Concept	2020 Q2	2019 Q2
Revenue	$1.093B	$743.2M
YoY Change	47.07%	4.05%
Cost Of Revenue	$1.208B	$480.2M
YoY Change	151.56%	11.73%
Gross Profit	-$115.0M	$263.0M
YoY Change	-143.73%	-7.56%
Gross Profit Margin	-10.52%	35.39%
Selling, General & Admin	$62.00M	$29.40M
YoY Change	110.88%	12.21%
% of Gross Profit		11.18%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$75.00M	$20.90M
YoY Change	258.85%	-18.04%
% of Gross Profit		7.95%
Operating Expenses	$62.00M	$36.20M
YoY Change	71.27%	19.47%
Operating Profit	-$208.0M	$226.8M
YoY Change	-191.71%	-10.78%
Interest Expense	-$69.00M	-$26.10M
YoY Change	164.37%	-16.61%
% of Operating Profit		-11.51%
Other Income/Expense, Net	$76.00M	-$43.40M
YoY Change	-275.12%	63.16%
Pretax Income	-$132.0M	$183.4M
YoY Change	-171.97%	-19.42%
Income Tax	-$25.00M	$22.00M
% Of Pretax Income		12.0%
Net Earnings	-$124.0M	$160.8M
YoY Change	-177.11%	-2.6%
Net Earnings / Revenue	-11.34%	21.64%
Basic Earnings Per Share	-$0.31	$0.59
Diluted Earnings Per Share	-$0.31	$0.57
COMMON SHARES
Basic Shares Outstanding	399.0M shares	275.8M shares
Diluted Shares Outstanding	399.0M shares	285.5M shares

Balance Sheet

Concept	2020 Q2	2019 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$74.00M	$377.0M
YoY Change	-80.37%	-53.05%
Cash & Equivalents	$73.70M	$377.2M
Short-Term Investments
Other Short-Term Assets	$90.20M	$42.30M
YoY Change	113.24%	57.84%
Inventory	$1.934B	$219.0M
Prepaid Expenses
Receivables	$482.2M	$193.1M
Other Receivables	$63.00M	$59.00M
Total Short-Term Assets	$2.642B	$1.119B
YoY Change	136.05%	-27.64%
LONG-TERM ASSETS
Property, Plant & Equipment	$4.548B	$1.597B
YoY Change	184.72%	47.72%
Goodwill	$139.3M
YoY Change
Intangibles	$192.6M
YoY Change
Long-Term Investments
YoY Change
Other Assets	$245.0M	$118.3M
YoY Change	107.1%	0.51%
Total Long-Term Assets	$5.848B	$2.274B
YoY Change	157.21%	51.12%
TOTAL ASSETS
Total Short-Term Assets	$2.642B	$1.119B
Total Long-Term Assets	$5.848B	$2.274B
Total Assets	$8.491B	$3.393B
YoY Change	150.23%	11.2%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$504.8M	$188.1M
YoY Change	168.37%	58.07%
Accrued Expenses	$288.3M	$90.00M
YoY Change	220.33%	5.76%
Deferred Revenue		$15.50M
YoY Change
Short-Term Debt	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$1.038B	$437.4M
YoY Change	137.31%	-7.9%
LONG-TERM LIABILITIES
Long-Term Debt	$4.452B	$2.105B
YoY Change	111.53%	-8.38%
Other Long-Term Liabilities	$278.4M	$149.7M
YoY Change	85.97%	-5.43%
Total Long-Term Liabilities	$4.730B	$2.254B
YoY Change	109.83%	-8.19%
TOTAL LIABILITIES
Total Short-Term Liabilities	$1.038B	$437.4M
Total Long-Term Liabilities	$4.730B	$2.254B
Total Liabilities	$7.373B	$3.108B
YoY Change	137.24%	-7.45%
SHAREHOLDERS EQUITY
Retained Earnings	-$3.043B	-$2.953B
YoY Change	3.04%	-27.85%
Common Stock
YoY Change
Preferred Stock
YoY Change
Treasury Stock (at cost)	$355.9M	$391.3M
YoY Change	-9.05%	165.29%
Treasury Stock Shares	29.49M shares	3.879M shares
Shareholders Equity	$792.9M	$285.6M
YoY Change
Total Liabilities & Shareholders Equity	$8.491B	$3.393B
YoY Change	150.23%	11.2%

Cashflow Statement

Concept	2020 Q2	2019 Q2
OPERATING ACTIVITIES
Net Income	-$124.0M	$160.8M
YoY Change	-177.11%	-2.6%
Depreciation, Depletion And Amortization	$75.00M	$20.90M
YoY Change	258.85%	-18.04%
Cash From Operating Activities	-$134.3M	$263.9M
YoY Change	-150.89%	181.94%
INVESTING ACTIVITIES
Capital Expenditures	-$144.8M	-$161.7M
YoY Change	-10.45%	444.44%
Acquisitions
YoY Change
Other Investing Activities	-$100.0K	-$5.100M
YoY Change	-98.04%	-492.31%
Cash From Investing Activities	-$144.9M	-$166.8M
YoY Change	-13.13%	487.32%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	166.0M	-150.1M
YoY Change	-210.59%	702.67%
NET CHANGE
Cash From Operating Activities	-134.3M	263.9M
Cash From Investing Activities	-144.9M	-166.8M
Cash From Financing Activities	166.0M	-150.1M
Net Change In Cash	-113.2M	-53.00M
YoY Change	113.58%	-213.98%
FREE CASH FLOW
Cash From Operating Activities	-$134.3M	$263.9M
Capital Expenditures	-$144.8M	-$161.7M
Free Cash Flow	$10.50M	$425.6M
YoY Change	-97.53%	245.17%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q2
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
	dei	Entity Central Index Key EntityCentralIndexKey	0000764065
CY2019Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.05
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.05
CY2020Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.06
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.125
CY2020Q2	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.125
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	600000000	shares
CY2020Q2	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	600000000	shares
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	301886794	shares
CY2020Q2	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	428645866	shares
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	270084005	shares
CY2020Q2	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	399159988	shares
CY2019Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	31802789	shares
CY2020Q2	us-gaap	Treasury Stock Shares TreasuryStockShares	29485878	shares
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2020-06-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	1-8944
	dei	Entity Registrant Name EntityRegistrantName	CLEVELAND-CLIFFS INC.
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	OH
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	34-1464672
	dei	Entity Address Address Line1 EntityAddressAddressLine1	200 Public Square,
	dei	Entity Address City Or Town EntityAddressCityOrTown	Cleveland,
	dei	Entity Address State Or Province EntityAddressStateOrProvince	OH
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	44114-2315
	dei	City Area Code CityAreaCode	216
	dei	Local Phone Number LocalPhoneNumber	694-5700
	dei	Security12b Title Security12bTitle	Common shares, par value $0.125 per share
	dei	Trading Symbol TradingSymbol	CLF
	dei	Security Exchange Name SecurityExchangeName	NYSE
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
CY2020Q3	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	399198070	shares
CY2020Q2	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	73700000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	352600000	USD
CY2020Q2	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	482200000	USD
CY2019Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	94000000.0	USD
CY2020Q2	us-gaap	Inventory Net InventoryNet	1933600000	USD
CY2019Q4	us-gaap	Inventory Net InventoryNet	317400000	USD
CY2020Q2	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	62600000	USD
CY2019Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	58600000	USD
CY2020Q2	us-gaap	Other Assets Current OtherAssetsCurrent	90200000	USD
CY2019Q4	us-gaap	Other Assets Current OtherAssetsCurrent	75300000	USD
CY2020Q2	us-gaap	Assets Current AssetsCurrent	2642300000	USD
CY2019Q4	us-gaap	Assets Current AssetsCurrent	897900000	USD
CY2020Q2	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	4547900000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1929000000.0	USD
CY2020Q2	us-gaap	Goodwill Goodwill	139300000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	2100000	USD
CY2020Q2	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	192600000	USD
CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	48100000	USD
CY2020Q2	us-gaap	Income Taxes Receivable Noncurrent IncomeTaxesReceivableNoncurrent	4100000	USD
CY2019Q4	us-gaap	Income Taxes Receivable Noncurrent IncomeTaxesReceivableNoncurrent	62700000	USD
CY2020Q2	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	506500000	USD
CY2019Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	459500000	USD
CY2020Q2	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	213000000.0	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	11700000	USD
CY2020Q2	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	245000000.0	USD
CY2019Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	92800000	USD
CY2020Q2	us-gaap	Assets Assets	8490700000	USD
CY2019Q4	us-gaap	Assets Assets	3503800000	USD
CY2020Q2	us-gaap	Accounts Payable Current AccountsPayableCurrent	504800000	USD
CY2019Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	193200000	USD
CY2020Q2	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	288300000	USD
CY2019Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	126300000	USD
CY2020Q2	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	244900000	USD
CY2019Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	89900000	USD
CY2020Q2	us-gaap	Liabilities Current LiabilitiesCurrent	1038000000.0	USD
CY2019Q4	us-gaap	Liabilities Current LiabilitiesCurrent	409400000	USD
CY2020Q2	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	4451600000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	2113800000	USD
CY2020Q2	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	191500000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	10500000	USD
CY2020Q2	clf	Intangible Liability Net IntangibleLiabilityNet	72300000	USD
CY2019Q4	clf	Intangible Liability Net IntangibleLiabilityNet	0	USD
CY2020Q2	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	1159600000	USD
CY2019Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	311500000	USD
CY2020Q2	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	181100000	USD
CY2019Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	163200000	USD
CY2020Q2	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	278400000	USD
CY2019Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	137500000	USD
CY2020Q2	us-gaap	Liabilities Liabilities	7372500000	USD
CY2019Q4	us-gaap	Liabilities Liabilities	3145900000	USD
CY2020Q2	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2019Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2020Q2	us-gaap	Common Stock Value Outstanding CommonStockValueOutstanding	53600000	USD
CY2019Q4	us-gaap	Common Stock Value Outstanding CommonStockValueOutstanding	37700000	USD
CY2020Q2	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	4443600000	USD
CY2019Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	3872100000	USD
CY2020Q2	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	-3042500000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	-2842400000	USD
CY2020Q2	us-gaap	Treasury Stock Value TreasuryStockValue	355900000	USD
CY2019Q4	us-gaap	Treasury Stock Value TreasuryStockValue	390700000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-305900000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-318800000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	792900000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	357900000	USD
CY2020Q2	us-gaap	Minority Interest MinorityInterest	325300000	USD
CY2019Q4	us-gaap	Minority Interest MinorityInterest	0	USD
CY2020Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1118200000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	357900000	USD
CY2020Q2	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	8490700000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	3503800000	USD
CY2020Q2	clf	Revenues Excluding Deferred Revenue Revenue Recognized RevenuesExcludingDeferredRevenueRevenueRecognized	1092700000	USD
CY2019Q2	clf	Revenues Excluding Deferred Revenue Revenue Recognized RevenuesExcludingDeferredRevenueRevenueRecognized	743200000	USD
	clf	Revenues Excluding Deferred Revenue Revenue Recognized RevenuesExcludingDeferredRevenueRevenueRecognized	1417200000	USD
	clf	Revenues Excluding Deferred Revenue Revenue Recognized RevenuesExcludingDeferredRevenueRevenueRecognized	900200000	USD
CY2020Q2	us-gaap	Deferred Revenue Revenue Recognized1 DeferredRevenueRevenueRecognized1	0	USD
CY2019Q2	us-gaap	Deferred Revenue Revenue Recognized1 DeferredRevenueRevenueRecognized1	0	USD
	us-gaap	Deferred Revenue Revenue Recognized1 DeferredRevenueRevenueRecognized1	34600000	USD
	us-gaap	Deferred Revenue Revenue Recognized1 DeferredRevenueRevenueRecognized1	0	USD
CY2020Q2	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	1207500000	USD
CY2019Q2	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	480200000	USD
	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	1563500000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-176000000.0	USD
	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	606300000	USD
CY2020Q2	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	62100000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	19300000	USD
CY2019Q2	us-gaap	Costs And Expenses CostsAndExpenses	516400000	USD
	us-gaap	Costs And Expenses CostsAndExpenses	1739000000.0	USD
	us-gaap	Costs And Expenses CostsAndExpenses	674200000	USD
CY2019Q2	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	29400000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	89600000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	56700000	USD
CY2020Q2	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	18400000	USD
CY2019Q2	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	0	USD
	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	60900000	USD
	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	0	USD
CY2020Q2	us-gaap	Other Operating Income Expense Net OtherOperatingIncomeExpenseNet	-13100000	USD
CY2019Q2	us-gaap	Other Operating Income Expense Net OtherOperatingIncomeExpenseNet	-6800000	USD
	us-gaap	Other Operating Income Expense Net OtherOperatingIncomeExpenseNet	-25000000.0	USD
	us-gaap	Other Operating Income Expense Net OtherOperatingIncomeExpenseNet	-11200000	USD
CY2020Q2	us-gaap	Costs And Expenses CostsAndExpenses	1301100000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2020Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	-208400000	USD
CY2019Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	226800000	USD
	us-gaap	Operating Income Loss OperatingIncomeLoss	-287200000	USD
	us-gaap	Operating Income Loss OperatingIncomeLoss	226000000.0	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	138700000	USD
CY2020Q2	us-gaap	Interest Income Expense Nonoperating Net InterestIncomeExpenseNonoperatingNet	-68700000	USD
CY2019Q2	us-gaap	Interest Income Expense Nonoperating Net InterestIncomeExpenseNonoperatingNet	-26100000	USD
	us-gaap	Interest Income Expense Nonoperating Net InterestIncomeExpenseNonoperatingNet	-99700000	USD
	us-gaap	Interest Income Expense Nonoperating Net InterestIncomeExpenseNonoperatingNet	-51200000	USD
CY2020Q2	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	129400000	USD
CY2019Q2	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-17900000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	132600000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-18200000	USD
CY2020Q2	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	15200000	USD
CY2019Q2	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	600000	USD
	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	21200000	USD
	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	1000000.0	USD
CY2020Q2	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	75900000	USD
CY2019Q2	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	-43400000	USD
	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	54100000	USD
	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	-68400000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-132500000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	183400000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-233100000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	157600000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-24700000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	18300000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	300000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.31
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-600000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	22000000.0	USD
CY2020Q2	us-gaap	Profit Loss ProfitLoss	-108100000	USD
CY2019Q2	us-gaap	Profit Loss ProfitLoss	160800000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-76100000	USD
	us-gaap	Profit Loss ProfitLoss	-156700000	USD
	us-gaap	Profit Loss ProfitLoss	138700000	USD
CY2020Q2	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	15800000	USD
CY2019Q2	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2020Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-123900000	USD
CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	160800000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-107800000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	161400000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-157000000.0	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	139300000	USD
CY2020Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-300000	USD
CY2019Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-600000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.59
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.51
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.49
CY2020Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
CY2019Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.31
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.59
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.51
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.49
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.31
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.57
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.51
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.47
CY2020Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
CY2019Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.31
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.57
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	19300000	USD
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.51
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.47
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	399088000	shares
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-96900000	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	15800000	USD
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	275769000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	348302000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	282647000	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	399088000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	285479000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	348302000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	293580000	shares
CY2020Q2	us-gaap	Profit Loss ProfitLoss	-108100000	USD
CY2019Q2	us-gaap	Profit Loss ProfitLoss	160800000	USD
	us-gaap	Profit Loss ProfitLoss	-156700000	USD
	us-gaap	Profit Loss ProfitLoss	138700000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-6000000.0	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-5800000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-11600000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-11500000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	700000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	0	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	-200000	USD
	us-gaap	Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	0	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	4500000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	-2100000	USD
	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	1500000	USD
	us-gaap	Other Comprehensive Income Loss Derivatives Qualifying As Hedges Net Of Tax OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax	600000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	0	USD
	us-gaap	Unrealized Gain Loss On Derivatives And Commodity Contracts UnrealizedGainLossOnDerivativesAndCommodityContracts	-8000000.0	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	164500000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-143800000	USD
	us-gaap	Unrealized Gain Loss On Derivatives And Commodity Contracts UnrealizedGainLossOnDerivativesAndCommodityContracts	27200000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-163100000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	150800000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	11200000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	3700000	USD
	us-gaap	Profit Loss ProfitLoss	-156700000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	12900000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	12100000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	150800000	USD
	us-gaap	Profit Loss ProfitLoss	138700000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	111500000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	40900000	USD
	clf	Amortizationof Inventory Stepup AmortizationofInventoryStepup	59400000	USD
	clf	Amortizationof Inventory Stepup AmortizationofInventoryStepup	0	USD
	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	250000000.0	USD
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-72500000	USD
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	18200000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	132600000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-18200000	USD
	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	0	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-112700000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	164500000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	28000000.0	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-28400000	USD
	us-gaap	Increase Decrease In Accounts Receivable And Other Operating Assets IncreaseDecreaseInAccountsReceivableAndOtherOperatingAssets	-365700000	USD
	us-gaap	Increase Decrease In Accounts Receivable And Other Operating Assets IncreaseDecreaseInAccountsReceivableAndOtherOperatingAssets	-145400000	USD
	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	126100000	USD
	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	148700000	USD
	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-327900000	USD
	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-62800000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-299200000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	151100000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	282900000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	300900000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	869300000	USD
	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	200000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-8500000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1152400000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-292400000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	252900000	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	1762900000	USD
	us-gaap	Proceeds From Issuance Of Senior Long Term Debt ProceedsFromIssuanceOfSeniorLongTermDebt	720900000	USD
	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	57900000	USD
	us-gaap	Payments Of Debt Issuance Costs PaymentsOfDebtIssuanceCosts	6800000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	999500000	USD
	us-gaap	Net Cash Provided By Used In Discontinued Operations NetCashProvidedByUsedInDiscontinuedOperations	-3200000	USD
	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	729300000	USD
	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	800000000.0	USD
	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	0	USD
	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	0	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	40800000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	28900000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-43600000	USD
	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-10900000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	1171100000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-307900000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-280500000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-449200000	USD
	us-gaap	Net Cash Provided By Used In Discontinued Operations NetCashProvidedByUsedInDiscontinuedOperations	-1600000	USD
	us-gaap	Net Cash Provided By Used In Continuing Operations NetCashProvidedByUsedInContinuingOperations	-278900000	USD
	us-gaap	Net Cash Provided By Used In Continuing Operations NetCashProvidedByUsedInContinuingOperations	-446000000.0	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	352600000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	823200000	USD
CY2020Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	73700000	USD
CY2019Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	377200000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	357900000	USD
CY2020Q1	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-46900000	USD
CY2020Q1	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	2100000	USD
CY2020Q1	us-gaap	Stock Issued During Period Value Acquisitions StockIssuedDuringPeriodValueAcquisitions	947400000	USD
CY2020Q1	us-gaap	Dividends Common Stock DividendsCommonStock	24000000.0	USD
CY2020Q1	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	5500000	USD
CY2020Q1	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1231000000.0	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-96900000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	2500000	USD
CY2020Q2	us-gaap	Dividends Common Stock DividendsCommonStock	100000	USD
CY2020Q2	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	18300000	USD
CY2020Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1118200000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	424200000	USD
CY2019Q1	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-13700000	USD
CY2019Q1	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-10000000.0	USD
CY2019Q1	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	124300000	USD
CY2019Q1	us-gaap	Dividends Common Stock DividendsCommonStock	14500000	USD
CY2019Q1	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	261700000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	164500000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	4600000	USD
CY2019Q2	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	128600000	USD
CY2019Q2	us-gaap	Dividends Common Stock DividendsCommonStock	16600000	USD
CY2019Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	285600000	USD
	us-gaap	Interest Paid Net InterestPaidNet	63000000.0	USD
CY2020Q2	us-gaap	Revenues Revenues	1092700000	USD
CY2019Q4	us-gaap	Inventory Finished Goods And Work In Process Net Of Reserves InventoryFinishedGoodsAndWorkInProcessNetOfReserves	192200000	USD
	us-gaap	Basis Of Accounting BasisOfAccounting	<div style="line-height:120%;padding-bottom:12px;text-align:justify;font-size:10pt;"><span style="font-family:Arial;font-size:10pt;font-weight:bold;">Business, Consolidation and Presentation</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;text-indent:48px;font-size:10pt;"><span style="font-family:Arial;font-size:10pt;">The accompanying </span><span style="font-family:Arial;font-size:10pt;">unaudited condensed consolidated financial statements</span><span style="font-family:Arial;font-size:10pt;"> have been prepared in accordance with SEC rules and regulations and, in the opinion of management, include all adjustments (consisting of normal recurring adjustments) necessary to present fairly the financial position, results of operations, comprehensive income (loss), cash flows and changes in equity for the periods presented. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Management bases its estimates on various assumptions and historical experience, which are believed to be reasonable; however, due to the inherent nature of estimates, actual results may differ significantly due to changed conditions or assumptions. The results of operations for the </span><span style="font-family:Arial;font-size:10pt;">three and six months ended</span><span style="font-family:Arial;font-size:10pt;"> </span><span style="font-family:Arial;font-size:10pt;">June 30, 2020</span><span style="font-family:Arial;font-size:10pt;"> are not necessarily indicative of results to be expected for the year ending </span><span style="font-family:Arial;font-size:10pt;">December 31, 2020</span><span style="font-family:Arial;font-size:10pt;"> or any other future period. Due to the acquisition of AK Steel, certain balances have become material and are no longer being condensed in our </span><span style="font-family:Arial;font-size:10pt;">Statements of Unaudited Condensed Consolidated Financial Position</span><span style="font-family:Arial;font-size:10pt;">, such as balances for </span><span style="font-family:Arial;font-size:10pt;font-style:italic;">Right-of-use asset, operating lease</span><span style="font-family:Arial;font-size:10pt;"> and </span><span style="font-family:Arial;font-size:10pt;font-style:italic;">Operating lease liability, non-current</span><span style="font-family:Arial;font-size:10pt;">. As a result, certain prior period amounts have been reclassified to conform with the current year presentation. These </span><span style="font-family:Arial;font-size:10pt;">unaudited condensed consolidated financial statements</span><span style="font-family:Arial;font-size:10pt;"> should be read in conjunction with the financial statements and notes included in our Annual Report on Form 10-K for the year ended </span><span style="font-family:Arial;font-size:10pt;">December 31, 2019</span><span style="font-family:Arial;font-size:10pt;"> and in our Quarterly Report on Form 10-Q for the three months ended March 31, 2020.</span></div>
	us-gaap	Nature Of Operations NatureOfOperations	<div style="line-height:120%;padding-bottom:12px;text-align:justify;text-indent:48px;font-size:10pt;"><span style="font-family:Arial;font-size:10pt;font-style:italic;font-weight:bold;">Acquisition of AK Steel</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;text-indent:48px;font-size:10pt;"><span style="font-family:Arial;font-size:10pt;">On March 13, 2020, we consummated the Merger, pursuant to which, upon the terms and subject to the conditions set forth in the Merger Agreement, Merger Sub was merged with and into AK Steel, with AK Steel surviving the Merger as a wholly owned subsidiary of Cliffs. Refer to </span><span style="font-family:Arial;font-size:10pt;">NOTE 3 - ACQUISITION OF AK STEEL</span><span style="font-family:Arial;font-size:10pt;"> for further information.</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;text-indent:48px;font-size:10pt;"><span style="font-family:Arial;font-size:10pt;">AK Steel is a leading North American producer of flat-rolled carbon, stainless and electrical steel products, primarily for the automotive, infrastructure and manufacturing markets. The acquisition of AK Steel has transformed us into a vertically integrated producer of value-added iron ore and steel products. </span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;text-indent:48px;font-size:10pt;"><span style="font-family:Arial;font-size:10pt;font-style:italic;font-weight:bold;">COVID-19</span></div><div style="line-height:120%;padding-bottom:12px;text-align:justify;text-indent:48px;font-size:10pt;"><span style="font-family:Arial;font-size:10pt;">In response to the COVID-19 pandemic, we made various operational changes to adjust to the demand for our products. Although steel and iron ore production have been considered “essential” by the states in which we operate, certain of our facilities and construction activities were temporarily idled during the second quarter of 2020. Nearly all of these temporarily idled facilities were restarted as of June 30, 2020, with the exception of the Dearborn hot-end operations and Mansfield operations, which were restarted in July 2020, and the Northshore mine, which we plan to restart in early August 2020.</span></div>
	us-gaap	Interest Paid Net InterestPaidNet	53200000	USD
CY2019Q2	us-gaap	Revenues Revenues	743200000	USD
	us-gaap	Revenues Revenues	1451800000	USD
	us-gaap	Revenues Revenues	900200000	USD
	us-gaap	Deferred Revenue Revenue Recognized1 DeferredRevenueRevenueRecognized1	34600000	USD
CY2020Q2	us-gaap	Revenues Revenues	1092700000	USD
CY2019Q2	us-gaap	Revenues Revenues	743200000	USD
	us-gaap	Revenues Revenues	1451800000	USD
	us-gaap	Revenues Revenues	900200000	USD
	us-gaap	Deferred Revenue Revenue Recognized1 DeferredRevenueRevenueRecognized1	34600000	USD
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	0	USD
CY2018Q4	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	0	USD
	us-gaap	Allowance For Doubtful Accounts Receivable Period Increase Decrease AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease	4300000	USD
	us-gaap	Allowance For Doubtful Accounts Receivable Period Increase Decrease AllowanceForDoubtfulAccountsReceivablePeriodIncreaseDecrease	0	USD
CY2020Q2	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	4300000	USD
CY2019Q2	us-gaap	Allowance For Doubtful Accounts Receivable AllowanceForDoubtfulAccountsReceivable	0	USD
CY2020Q2	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	1026400000	USD
CY2019Q4	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	114100000	USD
CY2019Q4	us-gaap	Inventory Supplies Net Of Reserves InventorySuppliesNetOfReserves	125200000	USD
CY2020Q2	us-gaap	Inventory Net InventoryNet	1933600000	USD
CY2019Q4	us-gaap	Inventory Net InventoryNet	317400000	USD
CY2020Q2	us-gaap	Inventory Work In Process Net Of Reserves InventoryWorkInProcessNetOfReserves	89500000	USD
CY2019Q4	us-gaap	Inventory Work In Process Net Of Reserves InventoryWorkInProcessNetOfReserves	68700000	USD
CY2020Q2	us-gaap	Inventory Raw Materials Net Of Reserves InventoryRawMaterialsNetOfReserves	438000000.0	USD
CY2019Q4	us-gaap	Inventory Raw Materials Net Of Reserves InventoryRawMaterialsNetOfReserves	9400000	USD
CY2020Q2	us-gaap	Inventory Finished Goods And Work In Process Net Of Reserves InventoryFinishedGoodsAndWorkInProcessNetOfReserves	1553900000	USD
CY2020Q2	us-gaap	Inventory Supplies Net Of Reserves InventorySuppliesNetOfReserves	379700000	USD
	us-gaap	Deferred Revenue Revenue Recognized1 DeferredRevenueRevenueRecognized1	34600000	USD
CY2020Q2	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	153800000	USD
CY2019Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	61700000	USD
CY2020Q2	us-gaap	Interest Payable Current InterestPayableCurrent	71500000	USD
CY2019Q4	us-gaap	Interest Payable Current InterestPayableCurrent	29000000.0	USD
CY2020Q2	us-gaap	Dividends Payable Current DividendsPayableCurrent	1100000	USD
CY2019Q4	us-gaap	Dividends Payable Current DividendsPayableCurrent	17800000	USD
CY2020Q2	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	61900000	USD
CY2019Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	17800000	USD
CY2020Q2	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	288300000	USD
CY2019Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	126300000	USD
	clf	Property Plantand Equipment Additions Including Discontinued Operations PropertyPlantandEquipmentAdditionsIncludingDiscontinuedOperations	230700000	USD
	clf	Property Plantand Equipment Additions Including Discontinued Operations PropertyPlantandEquipmentAdditionsIncludingDiscontinuedOperations	320900000	USD
	clf	Capital Expenditures Incurredbut Notyet Paid Increase Decrease In Period CapitalExpendituresIncurredbutNotyetPaidIncreaseDecreaseInPeriod	-91600000	USD
	clf	Capital Expenditures Incurredbut Notyet Paid Increase Decrease In Period CapitalExpendituresIncurredbutNotyetPaidIncreaseDecreaseInPeriod	3600000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	39400000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Finance Lease Liability RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability	24800000	USD
	clf	Government Grant Received GovernmentGrantReceived	0	USD
	clf	Government Grant Received GovernmentGrantReceived	8400000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	282900000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	300900000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	200000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	100000	USD
	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	60400000	USD
	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	117900000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	23300000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	9900000	USD
	us-gaap	Revenues Revenues	900200000	USD
	us-gaap	Number Of Reporting Units NumberOfReportingUnits	2	unit
CY2020Q2	us-gaap	Revenues Revenues	1092700000	USD
CY2019Q2	us-gaap	Revenues Revenues	743200000	USD
	us-gaap	Revenues Revenues	1451800000	USD
CY2020Q2	us-gaap	Profit Loss ProfitLoss	-108100000	USD
CY2020Q2	clf	Adjusted Ebitda Earnings Loss AdjustedEBITDAEarningsLoss	-82000000.0	USD
CY2019Q2	clf	Adjusted Ebitda Earnings Loss AdjustedEBITDAEarningsLoss	248400000	USD
	clf	Adjusted Ebitda Earnings Loss AdjustedEBITDAEarningsLoss	-59300000	USD
	clf	Adjusted Ebitda Earnings Loss AdjustedEBITDAEarningsLoss	269600000	USD
	us-gaap	Deferred Revenue Revenue Recognized1 DeferredRevenueRevenueRecognized1	34600000	USD
CY2019Q2	us-gaap	Profit Loss ProfitLoss	160800000	USD
	us-gaap	Profit Loss ProfitLoss	-156700000	USD
	us-gaap	Profit Loss ProfitLoss	138700000	USD
CY2020Q2	clf	Ebitda Earnings Loss EBITDAEarningsLoss	12900000	USD
CY2019Q2	clf	Ebitda Earnings Loss EBITDAEarningsLoss	230100000	USD
	clf	Ebitda Earnings Loss EBITDAEarningsLoss	-21600000	USD
	clf	Ebitda Earnings Loss EBITDAEarningsLoss	249300000	USD
CY2020Q2	clf	Adjusted Ebitda Earnings Loss AdjustedEBITDAEarningsLoss	-82000000.0	USD
CY2019Q2	clf	Adjusted Ebitda Earnings Loss AdjustedEBITDAEarningsLoss	248400000	USD
	clf	Adjusted Ebitda Earnings Loss AdjustedEBITDAEarningsLoss	-59300000	USD
	clf	Adjusted Ebitda Earnings Loss AdjustedEBITDAEarningsLoss	269600000	USD
CY2020Q2	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	15800000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	19300000	USD
CY2020Q2	clf	Depreciation Depletionand Amortization Attributableto Noncontrolling Interests DepreciationDepletionandAmortizationAttributabletoNoncontrollingInterests	4700000	USD
	clf	Depreciation Depletionand Amortization Attributableto Noncontrolling Interests DepreciationDepletionandAmortizationAttributabletoNoncontrollingInterests	5800000	USD
CY2020Q2	us-gaap	Assets Assets	8490700000	USD
CY2019Q4	us-gaap	Assets Assets	3503800000	USD
CY2020Q2	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	73000000.0	USD
CY2019Q2	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	191600000	USD
	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	230700000	USD
	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	320900000	USD
CY2020Q2	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	5885800000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	3027400000	USD
CY2020Q2	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	1337900000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	1098400000	USD
CY2020Q2	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	4547900000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1929000000.0	USD
CY2020Q2	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	93700000	USD
CY2019Q4	us-gaap	Finance Lease Right Of Use Asset FinanceLeaseRightOfUseAsset	49000000.0	USD
CY2020Q2	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	13600000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	23300000	USD
CY2019Q2	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	5900000	USD
	us-gaap	Interest Costs Capitalized InterestCostsCapitalized	9900000	USD
CY2020Q2	us-gaap	Depreciation Depreciation	75300000	USD
	us-gaap	Depreciation Depreciation	110700000	USD
CY2019Q2	us-gaap	Depreciation Depreciation	20900000	USD
	us-gaap	Depreciation Depreciation	40500000	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	220200000	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	27600000	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	192600000	USD
CY2020Q2	clf	Finite Lived Intangible Liability Gross FiniteLivedIntangibleLiabilityGross	75000000.0	USD
CY2020Q2	clf	Finite Lived Intangible Liability Accumulated Amortization FiniteLivedIntangibleLiabilityAccumulatedAmortization	2700000	USD
CY2020Q2	clf	Finite Lived Intangible Liability Net FiniteLivedIntangibleLiabilityNet	72300000	USD
CY2020Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	2400000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	3500000	USD
CY2019Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	200000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	400000	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear	5000000.0	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	10000000.0	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	10000000.0	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	10000000.0	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	10000000.0	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	10000000.0	USD
CY2020Q2	clf	Amortizationof Intangible Liability AmortizationofIntangibleLiability	600000	USD
	clf	Amortizationof Intangible Liability AmortizationofIntangibleLiability	2700000	USD
CY2020Q2	clf	Finite Lived Intangible Liabilities Amortization Credit Remainderof Fiscal Year FiniteLivedIntangibleLiabilitiesAmortizationCreditRemainderofFiscalYear	4100000	USD
CY2020Q2	clf	Finite Lived Intangible Liabilities Amortization Credit Next Twelve Months FiniteLivedIntangibleLiabilitiesAmortizationCreditNextTwelveMonths	8200000	USD
CY2020Q2	clf	Finite Lived Intangible Liabilities Amortization Credit Year Two FiniteLivedIntangibleLiabilitiesAmortizationCreditYearTwo	8200000	USD
CY2020Q2	clf	Finite Lived Intangible Liabilities Amortization Credit Year Three FiniteLivedIntangibleLiabilitiesAmortizationCreditYearThree	8200000	USD
CY2020Q2	clf	Finite Lived Intangible Liabilities Amortization Credit Year Four FiniteLivedIntangibleLiabilitiesAmortizationCreditYearFour	8200000	USD
CY2020Q2	clf	Finite Lived Intangible Liabilities Amortization Credit Year Five FiniteLivedIntangibleLiabilitiesAmortizationCreditYearFive	8200000	USD
CY2020Q2	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	4451600000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	2113800000	USD
CY2020Q2	us-gaap	Extinguishment Of Debt Amount ExtinguishmentOfDebtAmount	736400000	USD
CY2020Q2	clf	Reductionof Principal Long Term Debt ReductionofPrincipalLongTermDebt	181200000	USD
CY2020Q2	us-gaap	Extinguishment Of Debt Amount ExtinguishmentOfDebtAmount	747600000	USD
CY2020Q2	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	129400000	USD
	us-gaap	Extinguishment Of Debt Amount ExtinguishmentOfDebtAmount	1487500000	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	132600000	USD
CY2019Q2	us-gaap	Extinguishment Of Debt Amount ExtinguishmentOfDebtAmount	714000000.0	USD
CY2019Q2	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-17900000	USD
	us-gaap	Extinguishment Of Debt Amount ExtinguishmentOfDebtAmount	724000000.0	USD
CY2020Q2	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	2000000000.0	USD
	us-gaap	Gains Losses On Extinguishment Of Debt GainsLossesOnExtinguishmentOfDebt	-18200000	USD
CY2020Q2	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	2000000000.0	USD
CY2020Q2	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	2000000000.0	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	0	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	33500000	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	0	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	12800000	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	456500000	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	4137900000	USD
CY2020Q2	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	4640700000	USD
CY2020Q2	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	63200000	USD
CY2020Q2	us-gaap	Financial Liabilities Fair Value Disclosure FinancialLiabilitiesFairValueDisclosure	19700000	USD
CY2019Q4	us-gaap	Assets Fair Value Disclosure AssetsFairValueDisclosure	233400000	USD
CY2019Q4	us-gaap	Financial Liabilities Fair Value Disclosure FinancialLiabilitiesFairValueDisclosure	4300000	USD
	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	-3700000	USD
CY2020Q1	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	19600000	USD
CY2019Q1	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	106700000	USD
CY2019Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	45800000	USD
CY2018Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	91400000	USD
CY2020Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-40000000.0	USD
CY2019Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-74300000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-13800000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1 FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1	-89600000	USD
CY2020Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements	24300000	USD
CY2019Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements	62900000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements	24300000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements	62900000	USD
CY2020Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	35300000	USD
CY2019Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	118100000	USD
CY2020Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	35300000	USD
CY2019Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	118100000	USD
CY2020Q2	us-gaap	Fair Value Assets Measured On Recurring Basis Change In Unrealized Gain Loss FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	33600000	USD
CY2019Q2	us-gaap	Fair Value Assets Measured On Recurring Basis Change In Unrealized Gain Loss FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	73000000.0	USD
	us-gaap	Fair Value Assets Measured On Recurring Basis Change In Unrealized Gain Loss FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	13600000	USD
	us-gaap	Fair Value Assets Measured On Recurring Basis Change In Unrealized Gain Loss FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss	88300000	USD
CY2019Q2	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	-400000	USD
	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.311
	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.121
CY2020Q1	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	0	USD
CY2019Q1	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	9800000	USD
CY2019Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	1100000	USD
CY2018Q4	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	0	USD
CY2020Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Earnings FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings	0	USD
CY2019Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Earnings FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings	4500000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Earnings FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings	-600000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Gain Loss Included In Earnings FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings	-5300000	USD
CY2020Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	0	USD
CY2019Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	5300000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	1700000	USD
	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements	5300000	USD
CY2020Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	0	USD
CY2019Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	0	USD
CY2020Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	0	USD
CY2019Q2	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue	0	USD
CY2020Q2	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	300000	USD
	us-gaap	Income Tax Reconciliation Other Reconciling Items IncomeTaxReconciliationOtherReconcilingItems	-800000	USD
CY2020Q2	us-gaap	Asset Retirement Obligation AssetRetirementObligation	183300000	USD
CY2019Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	165300000	USD
CY2020Q2	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	2200000	USD
CY2019Q4	us-gaap	Asset Retirement Obligation Current AssetRetirementObligationCurrent	2100000	USD
CY2020Q2	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	181100000	USD
CY2019Q4	us-gaap	Asset Retirement Obligations Noncurrent AssetRetirementObligationsNoncurrent	163200000	USD
	clf	Asset Retirement Obligation Liabilities Assumed Acquisition AssetRetirementObligationLiabilitiesAssumedAcquisition	13900000	USD
CY2019Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	165300000	USD
CY2018Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	172400000	USD
	clf	Asset Retirement Obligation Liabilities Assumed Acquisition AssetRetirementObligationLiabilitiesAssumedAcquisition	13900000	USD
	clf	Asset Retirement Obligation Liabilities Assumed Acquisition AssetRetirementObligationLiabilitiesAssumedAcquisition	0	USD
	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	4900000	USD
	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	5100000	USD
	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	800000	USD
	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	400000	USD
CY2020Q2	us-gaap	Asset Retirement Obligation AssetRetirementObligation	183300000	USD
CY2019Q2	us-gaap	Asset Retirement Obligation AssetRetirementObligation	177100000	USD
CY2020Q2	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	41300000	USD
CY2019Q2	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	74800000	USD
	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	8500000	USD
	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	80300000	USD
CY2020Q2	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.125
CY2020Q1	us-gaap	Business Acquisition Equity Interest Issued Or Issuable Value Assigned BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned	617600000	USD
CY2020Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.06
CY2020Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.06
CY2019Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.10
CY2019Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.06
CY2019Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.05
CY2019Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.05
CY2018Q4	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	200000000	USD
CY2019Q2	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	100000000	USD
	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	24400000	shares
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	252900000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	315700000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Foreign Currency Translation Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax	0	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	-3100000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-318800000	USD
CY2020Q1	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	310100000	USD
CY2020Q1	us-gaap	Accumulated Other Comprehensive Income Loss Foreign Currency Translation Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax	-900000	USD
CY2020Q1	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	-6100000	USD
CY2020Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-317100000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	304100000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Foreign Currency Translation Adjustment Net Of Tax AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax	-200000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	-1600000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-305900000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	281100000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	-2800000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-283900000	USD
CY2019Q1	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	275400000	USD
CY2019Q1	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	-100000	USD
CY2019Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-275500000	USD
CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Defined Benefit Pension And Other Postretirement Plans Net Of Tax AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	269600000	USD
CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Net Of Tax AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax	-2200000	USD
CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-271800000	USD
CY2020Q2	us-gaap	Revenue From Related Parties RevenueFromRelatedParties	281800000	USD
CY2019Q2	us-gaap	Revenue From Related Parties RevenueFromRelatedParties	452400000	USD
	us-gaap	Revenue From Related Parties RevenueFromRelatedParties	292600000	USD
	us-gaap	Revenue From Related Parties RevenueFromRelatedParties	499300000	USD
CY2020Q2	us-gaap	Revenues Revenues	1092700000	USD
CY2019Q2	us-gaap	Revenues Revenues	743200000	USD
	us-gaap	Revenues Revenues	1451800000	USD
	us-gaap	Revenues Revenues	900200000	USD
CY2020Q2	clf	Percentage Of Related Party Revenue PercentageOfRelatedPartyRevenue	0.258
CY2019Q2	clf	Percentage Of Related Party Revenue PercentageOfRelatedPartyRevenue	0.609
	clf	Percentage Of Related Party Revenue PercentageOfRelatedPartyRevenue	0.202
	clf	Percentage Of Related Party Revenue PercentageOfRelatedPartyRevenue	0.555
CY2020Q2	us-gaap	Related Party Transaction Purchases From Related Party RelatedPartyTransactionPurchasesFromRelatedParty	9700000	USD
CY2019Q2	us-gaap	Related Party Transaction Purchases From Related Party RelatedPartyTransactionPurchasesFromRelatedParty	0	USD
	us-gaap	Related Party Transaction Purchases From Related Party RelatedPartyTransactionPurchasesFromRelatedParty	12200000	USD
	us-gaap	Related Party Transaction Purchases From Related Party RelatedPartyTransactionPurchasesFromRelatedParty	0	USD
	us-gaap	Deferred Revenue Revenue Recognized1 DeferredRevenueRevenueRecognized1	34600000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-107800000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	161400000	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	-157000000.0	USD
	us-gaap	Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest	139300000	USD
CY2020Q2	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	15800000	USD
CY2019Q2	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	19300000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-123600000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	161400000	USD
	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-176300000	USD
	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	139300000	USD
CY2020Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-300000	USD
CY2019Q2	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-600000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	300000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	-123900000	USD
	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-600000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	160800000	USD
	us-gaap	Net Income Loss NetIncomeLoss	-176000000.0	USD
	us-gaap	Net Income Loss NetIncomeLoss	138700000	USD
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	399100000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	275800000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	348300000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	282600000	shares
CY2020Q2	us-gaap	Incremental Common Shares Attributable To Conversion Of Debt Securities IncrementalCommonSharesAttributableToConversionOfDebtSecurities	0	shares
CY2019Q2	us-gaap	Incremental Common Shares Attributable To Conversion Of Debt Securities IncrementalCommonSharesAttributableToConversionOfDebtSecurities	6700000	shares
	us-gaap	Incremental Common Shares Attributable To Conversion Of Debt Securities IncrementalCommonSharesAttributableToConversionOfDebtSecurities	0	shares
	us-gaap	Incremental Common Shares Attributable To Conversion Of Debt Securities IncrementalCommonSharesAttributableToConversionOfDebtSecurities	6900000	shares
CY2020Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
CY2019Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	3000000.0	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	4100000	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	399100000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	285500000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	348300000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	293600000	shares
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.31
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.59
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-0.51
	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.49
CY2020Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
CY2019Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Basic Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerBasicShare	0
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.31
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.59
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.51
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.49
CY2020Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.31
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.57
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	-0.51
	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.47
CY2020Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
CY2019Q2	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
	us-gaap	Discontinued Operation Income Loss From Discontinued Operation Net Of Tax Per Diluted Share DiscontinuedOperationIncomeLossFromDiscontinuedOperationNetOfTaxPerDilutedShare	0
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.31
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.57
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.51
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.47
CY2020Q2	clf	Estimated Project Capital Expenditures EstimatedProjectCapitalExpenditures	1000000000	USD
	clf	Total Project Expenditures Excluding Capitalized Interest TotalProjectExpendituresExcludingCapitalizedInterest	894300000	USD
CY2020Q2	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	41400000	USD
CY2019Q4	us-gaap	Accrual For Environmental Loss Contingencies AccrualForEnvironmentalLossContingencies	2000000.0	USD
CY2020Q2	us-gaap	Accrued Environmental Loss Contingencies Current AccruedEnvironmentalLossContingenciesCurrent	6500000	USD
CY2019Q4	us-gaap	Accrued Environmental Loss Contingencies Current AccruedEnvironmentalLossContingenciesCurrent	300000	USD
CY2020Q2	us-gaap	Accrued Environmental Loss Contingencies Noncurrent AccruedEnvironmentalLossContingenciesNoncurrent	34900000	USD
CY2019Q4	us-gaap	Accrued Environmental Loss Contingencies Noncurrent AccruedEnvironmentalLossContingenciesNoncurrent	1700000	USD

Files In Submission

Name	View Source	Status
0000764065-20-000212-index-headers.html	Edgar Link	pending
0000764065-20-000212-index.html	Edgar Link	pending
0000764065-20-000212.txt	Edgar Link	pending
0000764065-20-000212-xbrl.zip	Edgar Link	pending
chart-ac8615604b2b58fbbd9.jpg	Edgar Link	pending
chart-dc6c33637f6a6d8d34d.jpg	Edgar Link	pending
clf-20200630.xsd	Edgar Link	pending
clf-20200630_cal.xml	Edgar Link	unprocessable
clf-20200630_def.xml	Edgar Link	unprocessable
clf-20200630_lab.xml	Edgar Link	unprocessable
clf-20200630_pre.xml	Edgar Link	unprocessable
clf-202063010xq.htm	Edgar Link	pending
clf-202063010xqex221.htm	Edgar Link	pending
clf-202063010xqex311.htm	Edgar Link	pending
clf-202063010xqex312.htm	Edgar Link	pending
clf-202063010xqex321.htm	Edgar Link	pending
clf-202063010xqex322.htm	Edgar Link	pending
clf-202063010xqex41.htm	Edgar Link	pending
clf-202063010xqex410.htm	Edgar Link	pending
clf-202063010xqex42.htm	Edgar Link	pending
clf-202063010xqex43.htm	Edgar Link	pending
clf-202063010xqex44.htm	Edgar Link	pending
clf-202063010xqex45.htm	Edgar Link	pending
clf-202063010xqex46.htm	Edgar Link	pending
clf-202063010xqex47.htm	Edgar Link	pending
clf-202063010xqex48.htm	Edgar Link	pending
clf-202063010xqex49.htm	Edgar Link	pending
clf-202063010xqex95.htm	Edgar Link	pending
clf-202063010xq_htm.xml	Edgar Link	completed
clf-logoa01a01a11.jpg	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
R12.htm	Edgar Link	pending
R13.htm	Edgar Link	pending
R14.htm	Edgar Link	pending
R15.htm	Edgar Link	pending
R16.htm	Edgar Link	pending
R17.htm	Edgar Link	pending
R18.htm	Edgar Link	pending
R19.htm	Edgar Link	pending
R2.htm	Edgar Link	pending
R20.htm	Edgar Link	pending
R21.htm	Edgar Link	pending
R22.htm	Edgar Link	pending
R23.htm	Edgar Link	pending
R24.htm	Edgar Link	pending
R25.htm	Edgar Link	pending
R26.htm	Edgar Link	pending
R27.htm	Edgar Link	pending
R28.htm	Edgar Link	pending
R29.htm	Edgar Link	pending
R3.htm	Edgar Link	pending
R30.htm	Edgar Link	pending
R31.htm	Edgar Link	pending
R32.htm	Edgar Link	pending
R33.htm	Edgar Link	pending
R34.htm	Edgar Link	pending
R35.htm	Edgar Link	pending
R36.htm	Edgar Link	pending
R37.htm	Edgar Link	pending
R38.htm	Edgar Link	pending
R39.htm	Edgar Link	pending
R4.htm	Edgar Link	pending
R40.htm	Edgar Link	pending
R41.htm	Edgar Link	pending
R42.htm	Edgar Link	pending
R43.htm	Edgar Link	pending
R44.htm	Edgar Link	pending
R45.htm	Edgar Link	pending
R46.htm	Edgar Link	pending
R47.htm	Edgar Link	pending
R48.htm	Edgar Link	pending
R49.htm	Edgar Link	pending
R5.htm	Edgar Link	pending
R50.htm	Edgar Link	pending
R51.htm	Edgar Link	pending
R52.htm	Edgar Link	pending
R53.htm	Edgar Link	pending
R54.htm	Edgar Link	pending
R55.htm	Edgar Link	pending
R56.htm	Edgar Link	pending
R57.htm	Edgar Link	pending
R58.htm	Edgar Link	pending
R59.htm	Edgar Link	pending
R6.htm	Edgar Link	pending
R60.htm	Edgar Link	pending
R61.htm	Edgar Link	pending
R62.htm	Edgar Link	pending
R63.htm	Edgar Link	pending
R64.htm	Edgar Link	pending
R65.htm	Edgar Link	pending
R66.htm	Edgar Link	pending
R67.htm	Edgar Link	pending
R68.htm	Edgar Link	pending
R69.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R70.htm	Edgar Link	pending
R71.htm	Edgar Link	pending
R72.htm	Edgar Link	pending
R73.htm	Edgar Link	pending
R74.htm	Edgar Link	pending
R75.htm	Edgar Link	pending
R76.htm	Edgar Link	pending
R77.htm	Edgar Link	pending
R78.htm	Edgar Link	pending
R79.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R80.htm	Edgar Link	pending
R81.htm	Edgar Link	pending
R82.htm	Edgar Link	pending
R83.htm	Edgar Link	pending
R84.htm	Edgar Link	pending
R85.htm	Edgar Link	pending
R86.htm	Edgar Link	pending
R87.htm	Edgar Link	pending
R88.htm	Edgar Link	pending
R89.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
R90.htm	Edgar Link	pending
R91.htm	Edgar Link	pending
R92.htm	Edgar Link	pending
R93.htm	Edgar Link	pending
R94.htm	Edgar Link	pending
R95.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending

Create your account

Find Stocks Worth Researching

Deeply Understand Businesses

Value Businesses Intelligently

$CLF
CLEVELAND-CLIFFS INC. Stock $clf

2020 Q2 Form 10-Q Financial Statement

#000076406520000212 Filed on July 30, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CLF CLEVELAND-CLIFFS INC. Stock $clf

2020 Q2 Form 10-Q Financial Statement

#000076406520000212 Filed on July 30, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$CLF
CLEVELAND-CLIFFS INC. Stock $clf