$WEC
WEC ENERGY GROUP, INC. Stock $wec

$wec Overview Financials Valuation SEC Filings Company Website

2011 Q4 Form 10-K Financial Statement

#000010781513000055 Filed on February 27, 2013

Income Statement

Concept	2011 Q4	2010 Q4	2010
Revenue	$1.113B	$1.090B	$4.203B
YoY Change	2.15%	2.69%	2.48%
Cost Of Revenue	$195.3M	$232.5M	$751.5M
YoY Change	-16.0%	-4.75%	-17.6%
Gross Profit	$917.9M	$857.3M	$3.451B
YoY Change	7.07%	4.91%	8.22%
Gross Profit Margin	82.46%	78.67%	82.12%
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$87.50M	$79.80M	$305.6M
YoY Change	9.65%	0.88%	-10.9%
% of Gross Profit	9.53%	9.31%	8.86%
Operating Expenses	$724.9M	$688.2M	$2.839B
YoY Change	5.33%	2.0%	2.89%
Operating Profit	$193.0M	$169.1M	$810.4M
YoY Change	14.13%	18.67%	22.73%
Interest Expense	-$42.10M	-$36.90M	$206.4M
YoY Change	14.09%	66.22%	31.72%
% of Operating Profit	-21.81%	-21.82%	25.47%
Other Income/Expense, Net	$19.60M	$14.70M	$40.20M
YoY Change	33.33%	226.67%	41.05%
Pretax Income	$170.5M	$193.5M	$704.3M
YoY Change	-11.89%	8.52%	19.13%
Income Tax	$56.40M	$67.90M	$249.9M
% Of Pretax Income	33.08%	35.09%	35.48%
Net Earnings	$116.0M	$125.9M	$456.5M
YoY Change	-7.86%	6.07%	19.38%
Net Earnings / Revenue	10.42%	11.55%	10.86%
Basic Earnings Per Share			$1.95
Diluted Earnings Per Share	$0.50	$0.53	$1.93
COMMON SHARES
Basic Shares Outstanding			233.8M shares
Diluted Shares Outstanding			236.7M shares

Balance Sheet

Concept	2011 Q4	2010 Q4	2010
SHORT-TERM ASSETS
Cash & Short-Term Investments	$14.00M	$25.00M	$25.00M
YoY Change	-44.0%	25.0%	25.0%
Cash & Equivalents	$14.10M	$24.50M	$25.00M
Short-Term Investments
Other Short-Term Assets	$87.10M	$85.00M	$219.0M
YoY Change	2.47%	-84.35%	-59.67%
Inventory	$382.0M	$379.0M	$379.0M
Prepaid Expenses	$140.3M	$125.6M
Receivables	$349.4M	$344.6M	$625.0M
Other Receivables	$155.0M	$84.00M	$84.00M
Total Short-Term Assets	$1.426B	$1.331B	$1.331B
YoY Change	7.14%	-12.94%	-12.95%
LONG-TERM ASSETS
Property, Plant & Equipment	$10.16B	$9.602B	$9.602B
YoY Change	5.82%	6.49%	6.5%
Goodwill	$441.9M	$441.9M
YoY Change	0.0%
Intangibles
YoY Change
Long-Term Investments	$393.0M	$376.0M	$376.0M
YoY Change	4.52%	4.74%	4.74%
Other Assets	$201.6M	$218.9M	$1.309B
YoY Change	-7.9%	-83.81%	-3.18%
Total Long-Term Assets	$12.44B	$11.73B	$11.73B
YoY Change	6.03%	5.01%	5.01%
TOTAL ASSETS
Total Short-Term Assets	$1.426B	$1.331B	$1.331B
Total Long-Term Assets	$12.44B	$11.73B	$11.73B
Total Assets	$13.86B	$13.06B	$13.06B
YoY Change	6.14%	2.85%	2.85%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$325.7M	$315.4M	$315.0M
YoY Change	3.27%	8.38%	8.25%
Accrued Expenses	$106.0M	$88.00M	$88.00M
YoY Change	20.45%
Deferred Revenue
YoY Change
Short-Term Debt	$670.0M	$658.0M	$658.0M
YoY Change	1.82%	-20.24%	-20.24%
Long-Term Debt Due	$32.60M	$473.4M	$473.0M
YoY Change	-93.11%	59.93%	59.8%
Total Short-Term Liabilities	$1.365B	$1.721B	$1.721B
YoY Change	-20.72%	-9.13%	-9.13%
LONG-TERM LIABILITIES
Long-Term Debt	$4.614B	$3.932B	$3.932B
YoY Change	17.35%	1.44%	1.44%
Other Long-Term Liabilities	$314.3M	$376.9M	$2.419B
YoY Change	-16.61%	-83.43%	6.33%
Total Long-Term Liabilities	$4.929B	$4.309B	$6.351B
YoY Change	14.38%	-29.95%	3.25%
TOTAL LIABILITIES
Total Short-Term Liabilities	$1.365B	$1.721B	$1.721B
Total Long-Term Liabilities	$4.929B	$4.309B	$6.351B
Total Liabilities	$6.293B	$6.030B	$9.227B
YoY Change	4.36%	-33.74%	1.38%
SHAREHOLDERS EQUITY
Retained Earnings
YoY Change
Common Stock	$3.963B	$3.802B
YoY Change	4.24%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$3.963B	$3.802B	$3.833B
YoY Change
Total Liabilities & Shareholders Equity	$13.86B	$13.06B	$13.06B
YoY Change	6.14%	2.85%	2.85%

Cashflow Statement

Concept	2011 Q4	2010 Q4	2010
OPERATING ACTIVITIES
Net Income	$116.0M	$125.9M	$456.5M
YoY Change	-7.86%	6.07%	19.38%
Depreciation, Depletion And Amortization	$87.50M	$79.80M	$305.6M
YoY Change	9.65%	0.88%	-10.9%
Cash From Operating Activities	$165.8M	$156.7M	$810.4M
YoY Change	5.81%	-19.72%	28.86%
INVESTING ACTIVITIES
Capital Expenditures	$218.6M	$252.6M	$798.2M
YoY Change	-13.46%	-3.4%	-2.01%
Acquisitions
YoY Change
Other Investing Activities	-$23.60M	$29.10M	$85.00M
YoY Change	-181.1%	1978.57%	-18.58%
Cash From Investing Activities	-$242.2M	-$223.5M	-$633.5M
YoY Change	8.37%	-14.07%	-13.94%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$156.6M
YoY Change			429.05%
Debt Paid & Issued, Net			$291.7M
YoY Change			31.93%
Cash From Financing Activities	75.40M	80.10M	-$172.6M
YoY Change	-5.87%	6.23%	-280.36%
NET CHANGE
Cash From Operating Activities	165.8M	156.7M	$810.4M
Cash From Investing Activities	-242.2M	-223.5M	-$633.5M
Cash From Financing Activities	75.40M	80.10M	-$172.6M
Net Change In Cash	-1.000M	13.30M	$4.300M
YoY Change	-107.52%	26.67%	-137.39%
FREE CASH FLOW
Cash From Operating Activities	$165.8M	$156.7M	$810.4M
Capital Expenditures	$218.6M	$252.6M	$798.2M
Free Cash Flow	-$52.80M	-$95.90M	$12.20M
YoY Change	-44.94%	44.65%	-106.57%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2011Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	325700000	USD
CY2012Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	368400000	USD
CY2011Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	349400000	USD
CY2012Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	285300000	USD
CY2011Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	3797800000	USD
CY2012Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	4036000000	USD
CY2012	us-gaap	Additions To Noncurrent Assets AdditionsToNoncurrentAssets	707000000	USD
CY2010	us-gaap	Additions To Noncurrent Assets AdditionsToNoncurrentAssets	798200000	USD
CY2011	us-gaap	Additions To Noncurrent Assets AdditionsToNoncurrentAssets	830800000	USD
CY2012	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	5200000	USD
CY2011	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	4600000	USD
CY2010	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	9500000	USD
CY2011	us-gaap	Adjustments To Additional Paid In Capital Tax Effect From Share Based Compensation AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation	11900000	USD
CY2010	us-gaap	Adjustments To Additional Paid In Capital Tax Effect From Share Based Compensation AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation	21900000	USD
CY2011	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	28500000	USD
CY2012	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	22000000	USD
CY2010	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	35100000	USD
CY2011Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	61700000	USD
CY2012Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	58000000	USD
CY2011Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	55500000	USD
CY2010Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	52600000	USD
CY2012Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	44300000	USD
CY2011	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	3000000	USD
CY2012	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	2800000	USD
CY2012	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	0	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Current DeferredTaxLiabilitiesCurrent	50100000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	2496600000	USD
CY2009Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	20200000	USD
CY2010	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	4300000	USD
CY2011	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-10400000	USD
CY2012Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	2865500000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2020700000	USD
CY2010Q4	us-gaap	Assets Assets	13059800000	USD
CY2011	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	600000	USD
CY2012	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	14000000	USD
CY2011	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	2200000	USD
CY2012	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	0	USD
CY2011	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	1500000	USD
CY2012Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	2339400000	USD
CY2011Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1329400000	USD
CY2011	us-gaap	Deferred Revenue Revenue Recognized DeferredRevenueRevenueRecognized	54400000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	250000000	USD
CY2011Q4	us-gaap	Assets Current AssetsCurrent	1426200000	USD
CY2012Q4	us-gaap	Assets Current AssetsCurrent	1313900000	USD
CY2012Q4	us-gaap	Assets Held For Sale Long Lived AssetsHeldForSaleLongLived	0	USD
CY2011Q4	us-gaap	Deferred Tax Assets Deferred Income DeferredTaxAssetsDeferredIncome	279700000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Liabilities Net Current DeferredTaxAssetsLiabilitiesNetCurrent	21600000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Liabilities Net Current DeferredTaxAssetsLiabilitiesNetCurrent	46300000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Liabilities Net Noncurrent DeferredTaxAssetsLiabilitiesNetNoncurrent	-2117000000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Liabilities Net Noncurrent DeferredTaxAssetsLiabilitiesNetNoncurrent	-1696100000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	872200000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	844500000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Net Current DeferredTaxAssetsNetCurrent	96000000	USD
CY2010Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	24500000	USD
CY2011Q4	us-gaap	Assets Assets	13862100000	USD
CY2012Q4	us-gaap	Assets Assets	14285000000	USD
CY2011	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	16700000	USD
CY2010	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	18200000	USD
CY2012	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	15700000	USD
CY2011Q4	us-gaap	Capital Lease Obligations CapitalLeaseObligations	132400000	USD
CY2012Q4	us-gaap	Capital Lease Obligations CapitalLeaseObligations	120000000	USD
CY2012Q4	us-gaap	Capital Lease Obligations Current CapitalLeaseObligationsCurrent	15800000	USD
CY2012Q4	us-gaap	Capital Lease Obligations Noncurrent CapitalLeaseObligationsNoncurrent	104200000	USD
CY2011Q4	us-gaap	Capital Leased Assets Gross CapitalLeasedAssetsGross	140300000	USD
CY2012Q4	us-gaap	Capital Leased Assets Gross CapitalLeasedAssetsGross	140300000	USD
CY2011Q4	us-gaap	Capital Leases Balance Sheet Assets By Major Class Net CapitalLeasesBalanceSheetAssetsByMajorClassNet	59200000	USD
CY2012Q4	us-gaap	Capital Leases Balance Sheet Assets By Major Class Net CapitalLeasesBalanceSheetAssetsByMajorClassNet	53500000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Due CapitalLeasesFutureMinimumPaymentsDue	256300000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Due Current CapitalLeasesFutureMinimumPaymentsDueCurrent	40400000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Due In Five Years CapitalLeasesFutureMinimumPaymentsDueInFiveYears	13900000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Due In Four Years CapitalLeasesFutureMinimumPaymentsDueInFourYears	45100000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Due In Three Years CapitalLeasesFutureMinimumPaymentsDueInThreeYears	43500000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Due In Two Years CapitalLeasesFutureMinimumPaymentsDueInTwoYears	41900000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Due Thereafter CapitalLeasesFutureMinimumPaymentsDueThereafter	71500000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Executory Costs CapitalLeasesFutureMinimumPaymentsExecutoryCosts	68400000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Interest Included In Payments CapitalLeasesFutureMinimumPaymentsInterestIncludedInPayments	67900000	USD
CY2012Q4	us-gaap	Capital Leases Future Minimum Payments Present Value Of Net Minimum Payments CapitalLeasesFutureMinimumPaymentsPresentValueOfNetMinimumPayments	120000000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Net Current DeferredTaxAssetsNetCurrent	71700000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Net Noncurrent DeferredTaxAssetsNetNoncurrent	748500000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Net Noncurrent DeferredTaxAssetsNetNoncurrent	800500000	USD
CY2012Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	293500000	USD
CY2011Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	303500000	USD
CY2012Q4	us-gaap	Capital Leases Lessee Balance Sheet Assets By Major Class Accumulated Deprecation CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation	86800000	USD
CY2011Q4	us-gaap	Capital Leases Lessee Balance Sheet Assets By Major Class Accumulated Deprecation CapitalLeasesLesseeBalanceSheetAssetsByMajorClassAccumulatedDeprecation	81100000	USD
CY2011Q4	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	8608000000	USD
CY2012Q4	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	8619300000	USD
CY2012Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	35600000	USD
CY2011Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	14100000	USD
CY2012	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	21500000	USD
CY2012Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	2900000	USD
CY2011Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	11900000	USD
CY2011Q4	us-gaap	Commercial Paper CommercialPaper	669900000	USD
CY2012Q4	us-gaap	Commercial Paper CommercialPaper	394600000	USD
CY2012Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2011Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2012Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	325000000	shares
CY2011Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	325000000	shares
CY2011Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	230486804	shares
CY2012Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	229039456	shares
CY2012Q4	us-gaap	Common Stock Value CommonStockValue	4135100000	USD
CY2011Q4	us-gaap	Common Stock Value CommonStockValue	3963300000	USD
CY2012Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	2915200000	USD
CY2011Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	2546700000	USD
CY2012Q4	us-gaap	Deferred Tax Liabilities Current DeferredTaxLiabilitiesCurrent	49700000	USD
CY2012Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	315900000	USD
CY2011Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	921300000	USD
CY2011	us-gaap	Cost Of Domestic Regulated Gas Revenue CostOfDomesticRegulatedGasRevenue	728700000	USD
CY2012	us-gaap	Cost Of Domestic Regulated Gas Revenue CostOfDomesticRegulatedGasRevenue	545800000	USD
CY2010	us-gaap	Cost Of Domestic Regulated Gas Revenue CostOfDomesticRegulatedGasRevenue	751500000	USD
CY2011	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-166700000	USD
CY2012	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-45900000	USD
CY2010	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	144900000	USD
CY2012Q4	us-gaap	Debt Instrument Face Amount DebtInstrumentFaceAmount	4772900000	USD
CY2012Q4	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	5447300000	USD
CY2011Q4	us-gaap	Debt Instrument Fair Value DebtInstrumentFairValue	5179900000	USD
CY2012	us-gaap	Debt Instrument Interest Rate Terms DebtInstrumentInterestRateTerms	We have the option to defer interest payments on the Junior Notes, from time to time, for one or more periods of up to 10 consecutive years per period. During any period in which we defer interest payments, we may not declare or pay any dividends or distributions on, or redeem, repurchase or acquire, our common stock.
CY2012	us-gaap	Debt Instrument Restrictive Covenants DebtInstrumentRestrictiveCovenants	The RCC provides that we may not redeem, defease or purchase and our subsidiaries may not purchase any Junior Notes on or before May 15, 2037, unless, subject to certain limitations described in the RCC, during the 180 days prior to the date of redemption, defeasance or purchase, we have received a specified amount of proceeds from the sale of qualifying securities.
CY2011Q4	us-gaap	Debt Instrument Unamortized Discount Premium Net DebtInstrumentUnamortizedDiscountPremiumNet	26900000	USD
CY2012Q4	us-gaap	Debt Instrument Unamortized Discount Premium Net DebtInstrumentUnamortizedDiscountPremiumNet	27000000	USD
CY2012	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	353400000	USD
CY2011	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	434800000	USD
CY2010	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	108600000	USD
CY2012	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	352200000	USD
CY2011	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	430600000	USD
CY2010	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	104900000	USD
CY2011Q4	us-gaap	Deferred Revenue Noncurrent DeferredRevenueNoncurrent	754500000	USD
CY2012Q4	us-gaap	Deferred Revenue Noncurrent DeferredRevenueNoncurrent	709700000	USD
CY2012	us-gaap	Deferred Revenue Revenue Recognized DeferredRevenueRevenueRecognized	54900000	USD
CY2010	us-gaap	Deferred Revenue Revenue Recognized DeferredRevenueRevenueRecognized	34600000	USD
CY2012Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	1507100000	USD
CY2012	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Decrease On Accumulated Postretirement Benefit Obligation1 DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnAccumulatedPostretirementBenefitObligation1	-23500000	USD
CY2012	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Decrease On Service And Interest Cost Components1 DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnServiceAndInterestCostComponents1	-3200000	USD
CY2012	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Increase On Accumulated Postretirement Benefit Obligation DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation	27800000	USD
CY2012	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Increase On Service And Interest Cost Components DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnServiceAndInterestCostComponents	4000000	USD
CY2012	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	371700000	USD
CY2010	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	317400000	USD
CY2011	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	336400000	USD
CY2012	us-gaap	Depreciation And Amortization DepreciationAndAmortization	364200000	USD
CY2010	us-gaap	Depreciation And Amortization DepreciationAndAmortization	305600000	USD
CY2011	us-gaap	Depreciation And Amortization DepreciationAndAmortization	330200000	USD
CY2012	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	364200000	USD
CY2010	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	305600000	USD
CY2011	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	330200000	USD
CY2011Q4	us-gaap	Derivative Assets DerivativeAssets	20600000	USD
CY2012Q4	us-gaap	Derivative Assets DerivativeAssets	17900000	USD
CY2011Q4	us-gaap	Derivative Financial Instruments Liabilities Fair Value Disclosure DerivativeFinancialInstrumentsLiabilitiesFairValueDisclosure	9200000	USD
CY2012Q4	us-gaap	Derivative Financial Instruments Liabilities Fair Value Disclosure DerivativeFinancialInstrumentsLiabilitiesFairValueDisclosure	500000	USD
CY2012	us-gaap	Derivative Instruments Gain Loss Recognized In Income Net DerivativeInstrumentsGainLossRecognizedInIncomeNet	-28400000	USD
CY2011	us-gaap	Derivative Instruments Gain Loss Recognized In Income Net DerivativeInstrumentsGainLossRecognizedInIncomeNet	-14000000	USD
CY2011	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	242000000	USD
CY2010	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	187000000	USD
CY2012	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	276300000	USD
CY2012	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.37
CY2010	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.95
CY2011	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.26
CY2010	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.93
CY2012	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.35
CY2011	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.24
CY2012	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350
CY2010	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350
CY2011	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Deductions Qualified Production Activities EffectiveIncomeTaxRateReconciliationDeductionsQualifiedProductionActivities	-0.015
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Deductions Qualified Production Activities EffectiveIncomeTaxRateReconciliationDeductionsQualifiedProductionActivities	-0.016
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Deductions Qualified Production Activities EffectiveIncomeTaxRateReconciliationDeductionsQualifiedProductionActivities	-0.018
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.003
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.003
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.007
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	-0.005
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	-0.005
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Investment EffectiveIncomeTaxRateReconciliationTaxCreditsInvestment	-0.001
CY2011	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	-0.011
CY2010	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	-0.010
CY2012	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits Other EffectiveIncomeTaxRateReconciliationTaxCreditsOther	-0.019
CY2011Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	105900000	USD
CY2012Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	100900000	USD
CY2012	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	8800000	USD
CY2010	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	14100000	USD
CY2011	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	11400000	USD
CY2011Q4	us-gaap	Energy Related Inventory EnergyRelatedInventory	382000000	USD
CY2012Q4	us-gaap	Energy Related Inventory EnergyRelatedInventory	360700000	USD
CY2011Q4	us-gaap	Energy Related Inventory Natural Gas In Storage EnergyRelatedInventoryNaturalGasInStorage	98700000	USD
CY2012Q4	us-gaap	Energy Related Inventory Natural Gas In Storage EnergyRelatedInventoryNaturalGasInStorage	73300000	USD
CY2011Q4	us-gaap	Energy Related Inventory Other Fossil Fuel EnergyRelatedInventoryOtherFossilFuel	169200000	USD
CY2012Q4	us-gaap	Energy Related Inventory Other Fossil Fuel EnergyRelatedInventoryOtherFossilFuel	165500000	USD
CY2012	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	52600000	USD
CY2011	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	49700000	USD
CY2010	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	49300000	USD
CY2012Q4	us-gaap	Equity Method Investment Ownership Percentage EquityMethodInvestmentOwnershipPercentage	0.50
CY2012Q4	us-gaap	Equity Method Investment Underlying Equity In Net Assets EquityMethodInvestmentUnderlyingEquityInNetAssets	3600000000	USD
CY2011	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	13400000	USD
CY2012	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	0	USD
CY2012	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.00
CY2010	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.01
CY2011	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.06
CY2011	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.06
CY2010	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.01
CY2010	us-gaap	Gain Loss On Sale Of Property GainLossOnSaleOfProperty	4400000	USD
CY2011	us-gaap	Gain Loss On Sale Of Property GainLossOnSaleOfProperty	2400000	USD
CY2012	us-gaap	Gain Loss On Sale Of Property GainLossOnSaleOfProperty	2700000	USD
CY2012Q4	us-gaap	Goodwill Goodwill	441900000	USD
CY2011Q4	us-gaap	Goodwill Goodwill	441900000	USD
CY2012	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-12100000	USD
CY2010	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-14100000	USD
CY2010	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-40000000	USD
CY2010	us-gaap	Increase Decrease In Restricted Cash IncreaseDecreaseInRestrictedCash	-186200000	USD
CY2012	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2011	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	512800000	USD
CY2010	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	454400000	USD
CY2012	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	546300000	USD
CY2010	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	704300000	USD
CY2012	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	852600000	USD
CY2011	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	776700000	USD
CY2010	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.94
CY2012	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.37
CY2011	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.20
CY2010	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.92
CY2011	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.18
CY2012	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.35
CY2010	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	2100000	USD
CY2012	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.00
CY2012	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	65500000	USD
CY2010	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	59900000	USD
CY2011	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	61600000	USD
CY2012	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	306300000	USD
CY2010	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	249900000	USD
CY2011	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	263900000	USD
CY2011	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	27000000	USD
CY2012	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	164000000	USD
CY2012	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-14900000	USD
CY2010	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	22000000	USD
CY2011	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	44100000	USD
CY2012	us-gaap	Increase Decrease In Restricted Cash IncreaseDecreaseInRestrictedCash	-42800000	USD
CY2011	us-gaap	Increase Decrease In Restricted Cash IncreaseDecreaseInRestrictedCash	37200000	USD
CY2010	us-gaap	Income Tax Reconciliation Deductions Qualified Production Activities IncomeTaxReconciliationDeductionsQualifiedProductionActivities	12600000	USD
CY2012	us-gaap	Income Tax Reconciliation Deductions Qualified Production Activities IncomeTaxReconciliationDeductionsQualifiedProductionActivities	12600000	USD
CY2011	us-gaap	Income Tax Reconciliation Deductions Qualified Production Activities IncomeTaxReconciliationDeductionsQualifiedProductionActivities	12600000	USD
CY2011	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	271800000	USD
CY2012	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	298400000	USD
CY2010	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	246500000	USD
CY2011	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-1700000	USD
CY2012	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	6600000	USD
CY2010	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	2400000	USD
CY2011	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	40100000	USD
CY2012	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	43300000	USD
CY2010	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	35800000	USD
CY2011	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	4200000	USD
CY2010	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	3600000	USD
CY2012	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	1200000	USD
CY2012	us-gaap	Income Tax Reconciliation Tax Credits Other IncomeTaxReconciliationTaxCreditsOther	15900000	USD
CY2011	us-gaap	Income Tax Reconciliation Tax Credits Other IncomeTaxReconciliationTaxCreditsOther	8700000	USD
CY2010	us-gaap	Income Tax Reconciliation Tax Credits Other IncomeTaxReconciliationTaxCreditsOther	7200000	USD
CY2010	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	166700000	USD
CY2012Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	98100000	USD
CY2011Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	155100000	USD
CY2010	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	21300000	USD
CY2011	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	11800000	USD
CY2012	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	43800000	USD
CY2012	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-38300000	USD
CY2010	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	50400000	USD
CY2011	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-30100000	USD
CY2010	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	-42700000	USD
CY2012	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	57900000	USD
CY2011	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	-87400000	USD
CY2012	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-21300000	USD
CY2011	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	2900000	USD
CY2010	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	1000000	USD
CY2011	us-gaap	Increase Decrease In Other Deferred Liability IncreaseDecreaseInOtherDeferredLiability	25900000	USD
CY2012	us-gaap	Increase Decrease In Other Deferred Liability IncreaseDecreaseInOtherDeferredLiability	9200000	USD
CY2010	us-gaap	Increase Decrease In Other Deferred Liability IncreaseDecreaseInOtherDeferredLiability	25900000	USD
CY2011	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	20500000	USD
CY2012	us-gaap	Interest Expense InterestExpense	248200000	USD
CY2010	us-gaap	Interest Expense InterestExpense	206400000	USD
CY2011	us-gaap	Interest Expense InterestExpense	235800000	USD
CY2012	us-gaap	Interest Paid Net InterestPaidNet	241200000	USD
CY2010	us-gaap	Interest Paid Net InterestPaidNet	198000000	USD
CY2011	us-gaap	Interest Paid Net InterestPaidNet	234000000	USD
CY2012Q4	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	121900000	USD
CY2011Q4	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	114100000	USD
CY2010	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-633500000	USD
CY2010	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	810400000	USD
CY2012Q4	us-gaap	Investments In Affiliates Subsidiaries Associates And Joint Ventures InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures	378300000	USD
CY2011Q4	us-gaap	Investments In Affiliates Subsidiaries Associates And Joint Ventures InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures	349700000	USD
CY2011Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	13862100000	USD
CY2012Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	14285000000	USD
CY2011Q4	us-gaap	Liabilities Current LiabilitiesCurrent	1364500000	USD
CY2012Q4	us-gaap	Liabilities Current LiabilitiesCurrent	1443300000	USD
CY2012Q4	us-gaap	Line Of Credit Facility Amount Outstanding LineOfCreditFacilityAmountOutstanding	394600000	USD
CY2012Q4	us-gaap	Line Of Credit Facility Remaining Borrowing Capacity LineOfCreditFacilityRemainingBorrowingCapacity	1200000000	USD
CY2012	us-gaap	Long Term Contract For Purchase Of Electric Power Amount Of Long Term Debt Or Lease Obligation Outstanding LongTermContractForPurchaseOfElectricPowerAmountOfLongTermDebtOrLeaseObligationOutstanding	256300000	USD
CY2010	us-gaap	Long Term Contract For Purchase Of Electric Power Annual Minimum Debt Service Payment Required LongTermContractForPurchaseOfElectricPowerAnnualMinimumDebtServicePaymentRequired	64200000	USD
CY2011	us-gaap	Long Term Contract For Purchase Of Electric Power Annual Minimum Debt Service Payment Required LongTermContractForPurchaseOfElectricPowerAnnualMinimumDebtServicePaymentRequired	65900000	USD
CY2012	us-gaap	Long Term Contract For Purchase Of Electric Power Annual Minimum Debt Service Payment Required LongTermContractForPurchaseOfElectricPowerAnnualMinimumDebtServicePaymentRequired	45800000	USD
CY2012	us-gaap	Long Term Contract For Purchase Of Electric Power Date Of Contract Expiration LongTermContractForPurchaseOfElectricPowerDateOfContractExpiration	2022-12-31
CY2011Q4	us-gaap	Long Term Debt LongTermDebt	4541400000	USD
CY2012Q4	us-gaap	Long Term Debt LongTermDebt	4772900000	USD
CY2012Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	4453800000	USD
CY2011Q4	us-gaap	Long Term Debt And Capital Lease Obligations LongTermDebtAndCapitalLeaseObligations	4614300000	USD
CY2012Q4	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	412100000	USD
CY2011Q4	us-gaap	Long Term Debt And Capital Lease Obligations Current LongTermDebtAndCapitalLeaseObligationsCurrent	32600000	USD
CY2012Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	3597800000	USD
CY2012Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	396300000	USD
CY2012Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	29500000	USD
CY2012Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	27400000	USD
CY2012Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	399500000	USD
CY2012Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	322400000	USD
CY2011Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	4614300000	USD
CY2012Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	4453800000	USD
CY2012Q4	us-gaap	Long Term Investments LongTermInvestments	413800000	USD
CY2011Q4	us-gaap	Long Term Investments LongTermInvestments	393300000	USD
CY2011	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-111300000	USD
CY2012	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-422800000	USD
CY2010	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-172600000	USD
CY2011	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-892500000	USD
CY2012	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-729600000	USD
CY2012	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	1173900000	USD
CY2011	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	993400000	USD
CY2012	us-gaap	Net Income Loss NetIncomeLoss	546300000	USD
CY2011	us-gaap	Net Income Loss NetIncomeLoss	526200000	USD
CY2010	us-gaap	Net Income Loss NetIncomeLoss	456500000	USD
CY2012	us-gaap	Operating Income Loss OperatingIncomeLoss	1000300000	USD
CY2010	us-gaap	Operating Income Loss OperatingIncomeLoss	810400000	USD
CY2011	us-gaap	Operating Income Loss OperatingIncomeLoss	887300000	USD
CY2012Q4	us-gaap	Operating Leases Future Minimum Payments Due OperatingLeasesFutureMinimumPaymentsDue	47100000	USD
CY2012Q4	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	6500000	USD
CY2012Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	3200000	USD
CY2012Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	3700000	USD
CY2012Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	3900000	USD
CY2012Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	3900000	USD
CY2012Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	25900000	USD
CY2011Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	867100000	USD
CY2012Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	838500000	USD
CY2012	us-gaap	Other Amortization Of Deferred Charges OtherAmortizationOfDeferredCharges	0	USD
CY2011	us-gaap	Other Amortization Of Deferred Charges OtherAmortizationOfDeferredCharges	0	USD
CY2010	us-gaap	Other Amortization Of Deferred Charges OtherAmortizationOfDeferredCharges	-198400000	USD
CY2012Q4	us-gaap	Other Assets Current OtherAssetsCurrent	107900000	USD
CY2011Q4	us-gaap	Other Assets Current OtherAssetsCurrent	87100000	USD
CY2012Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	204200000	USD
CY2011Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	201600000	USD
CY2011Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	230400000	USD
CY2012Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	167300000	USD
CY2012Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	285200000	USD
CY2011Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	314300000	USD
CY2011Q4	us-gaap	Other Long Term Investments OtherLongTermInvestments	43600000	USD
CY2012Q4	us-gaap	Other Long Term Investments OtherLongTermInvestments	35500000	USD
CY2012	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	34800000	USD
CY2011	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	62700000	USD
CY2010	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	40200000	USD
CY2010	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	85000000	USD
CY2011	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	59400000	USD
CY2012	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	58400000	USD
CY2012	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	153200000	USD
CY2010	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	156600000	USD
CY2011	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	193900000	USD
CY2012	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	276300000	USD
CY2011	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	242000000	USD
CY2010	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	187000000	USD
CY2012	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	15700000	USD
CY2010	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	5200000	USD
CY2011	us-gaap	Payments To Acquire Interest In Subsidiaries And Affiliates PaymentsToAcquireInterestInSubsidiariesAndAffiliates	6600000	USD
CY2012	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	707000000	USD
CY2011	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	830800000	USD
CY2010	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	798200000	USD
CY2010	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	0	USD
CY2012	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	100000000	USD
CY2011	us-gaap	Pension And Other Postretirement Benefit Contributions PensionAndOtherPostretirementBenefitContributions	277400000	USD
CY2012Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	244000000	USD
CY2011Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	222700000	USD
CY2012Q4	us-gaap	Postemployment Benefits Liability Current And Noncurrent PostemploymentBenefitsLiabilityCurrentAndNoncurrent	4000000	USD
CY2012Q4	us-gaap	Preferred Stock Value PreferredStockValue	30400000	USD
CY2011Q4	us-gaap	Preferred Stock Value PreferredStockValue	30400000	USD
CY2012Q4	us-gaap	Prepaid Expense Current PrepaidExpenseCurrent	145500000	USD
CY2011Q4	us-gaap	Prepaid Expense Current PrepaidExpenseCurrent	140300000	USD
CY2012	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	107000000	USD
CY2011	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	109100000	USD
CY2011	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	720000000	USD
CY2010	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	530000000	USD
CY2012	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	251800000	USD
CY2010	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	9000000	USD
CY2011	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	4800000	USD
CY2012	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	700000	USD
CY2011	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	12000000	USD
CY2012	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-275300000	USD
CY2010	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-167200000	USD
CY2011	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	41500000	USD
CY2012	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	8700000	USD
CY2010	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	68700000	USD
CY2010	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	90900000	USD
CY2011	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	54400000	USD
CY2012	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	49800000	USD
CY2012	us-gaap	Profit Loss ProfitLoss	546300000	USD
CY2010	us-gaap	Profit Loss ProfitLoss	456500000	USD
CY2011	us-gaap	Profit Loss ProfitLoss	526200000	USD
CY2012Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	10572200000	USD
CY2011Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	10160400000	USD
CY2012Q4	us-gaap	Property Plant And Equipment Other PropertyPlantAndEquipmentOther	14238800000	USD
CY2011Q4	us-gaap	Property Plant And Equipment Other PropertyPlantAndEquipmentOther	12977700000	USD
CY2012	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	35300000	USD
CY2010	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	32500000	USD
CY2011	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	59400000	USD
CY2012	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Interest PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest	14700000	USD
CY2010	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Interest PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest	13500000	USD
CY2011	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Interest PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest	24700000	USD
CY2011	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	466600000	USD
CY2010	us-gaap	Repayments Of Unsecured Debt RepaymentsOfUnsecuredDebt	281500000	USD
CY2012Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	2700000	USD
CY2011Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	45500000	USD
CY2012	us-gaap	Public Utilities Disclosure Of Rate Matters PublicUtilitiesDisclosureOfRateMatters	Our retail electric rates in Wisconsin are established by the PSCW and include base amounts for fuel and purchased power costs. Beginning in January 2011, the electric fuel rules in Wisconsin allow us to defer, for subsequent rate recovery or refund, any under-collection or over-collection of fuel costs that are outside of the symmetrical fuel cost tolerance, which the PSCW set at plus or minus 2% of the approved fuel cost plan. The deferred amounts are subject to an excess revenues test. Our retail gas rates include monthly adjustments which permit the recovery or refund of actual purchased gas costs. We defer any difference between actual gas costs incurred (adjusted for a sharing mechanism) and costs recovered through rates as a current asset or liability. The deferred balance is returned to or recovered from customers at intervals throughout the year.
CY2012	us-gaap	Public Utilities Property Plant And Equipment Disclosure Of Composite Depreciation Rate For Plants In Service PublicUtilitiesPropertyPlantAndEquipmentDisclosureOfCompositeDepreciationRateForPlantsInService	0.029
CY2011	us-gaap	Public Utilities Property Plant And Equipment Disclosure Of Composite Depreciation Rate For Plants In Service PublicUtilitiesPropertyPlantAndEquipmentDisclosureOfCompositeDepreciationRateForPlantsInService	0.028
CY2010	us-gaap	Public Utilities Property Plant And Equipment Disclosure Of Composite Depreciation Rate For Plants In Service PublicUtilitiesPropertyPlantAndEquipmentDisclosureOfCompositeDepreciationRateForPlantsInService	0.028
CY2011Q4	us-gaap	Public Utilities Property Plant And Equipment Plant In Service PublicUtilitiesPropertyPlantAndEquipmentPlantInService	9179900000	USD
CY2012Q4	us-gaap	Public Utilities Property Plant And Equipment Plant In Service PublicUtilitiesPropertyPlantAndEquipmentPlantInService	10202800000	USD
CY2012	us-gaap	Reclassifications Reclassifications	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;font-style:italic;font-weight:bold;">Reclassifications:   </font><font style="font-family:Arial;font-size:10pt;">Certain prior period amounts have been reclassified on a basis consistent with the current period financial statement presentation.</font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;font-style:italic;font-weight:bold;">Revenues:</font><font style="font-family:Arial;font-size:10pt;">   We recognize energy revenues on the accrual basis and include estimated amounts for services rendered but not billed.</font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;font-size:10pt;"><font style="font-family:Arial;font-size:10pt;">Our retail electric rates in Wisconsin are established by the PSCW and include base amounts for fuel and purchased power costs. Beginning in January 2011, the electric fuel rules in Wisconsin allow us to defer, for subsequent rate recovery</font></div></div>
CY2012	us-gaap	Recognition Of Deferred Revenue RecognitionOfDeferredRevenue	0	USD
CY2010	us-gaap	Recognition Of Deferred Revenue RecognitionOfDeferredRevenue	100800000	USD
CY2011	us-gaap	Recognition Of Deferred Revenue RecognitionOfDeferredRevenue	3500000	USD
CY2011Q4	us-gaap	Regulatory Assets RegulatoryAssets	1265700000	USD
CY2012Q4	us-gaap	Regulatory Assets RegulatoryAssets	1380300000	USD
CY2011Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	1238700000	USD
CY2012Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	1339000000	USD
CY2011Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	915900000	USD
CY2012Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	868300000	USD
CY2011Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	902000000	USD
CY2012Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	866500000	USD
CY2011Q4	us-gaap	Remaining Amounts Of Regulatory Assets For Which No Return On Investment During Recovery Period Is Provided RemainingAmountsOfRegulatoryAssetsForWhichNoReturnOnInvestmentDuringRecoveryPeriodIsProvided	11000000	USD
CY2012Q4	us-gaap	Remaining Amounts Of Regulatory Assets For Which No Return On Investment During Recovery Period Is Provided RemainingAmountsOfRegulatoryAssetsForWhichNoReturnOnInvestmentDuringRecoveryPeriodIsProvided	6600000	USD
CY2011	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	31300000	USD
CY2012	us-gaap	Repayments Of Long Term Capital Lease Obligations RepaymentsOfLongTermCapitalLeaseObligations	32500000	USD
CY2012	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	20300000	USD
CY2010	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	291700000	USD
CY2011Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	45500000	USD
CY2012Q4	us-gaap	Restricted Cash And Cash Equivalents At Carrying Value RestrictedCashAndCashEquivalentsAtCarryingValue	2700000	USD
CY2011	us-gaap	Sale Of Stock Percentage Of Ownership Before Transaction SaleOfStockPercentageOfOwnershipBeforeTransaction	0.25
CY2010	us-gaap	Sales Revenue Energy Services SalesRevenueEnergyServices	4202500000	USD
CY2012	us-gaap	Sales Revenue Energy Services SalesRevenueEnergyServices	4246400000	USD
CY2011	us-gaap	Sales Revenue Energy Services SalesRevenueEnergyServices	4486400000	USD
CY2010	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.037
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.190
CY2010	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.203
CY2013Q1	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	37.46
CY2011	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y6M
CY2012	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	49800000	USD
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.190
CY2012Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	7217394	shares
CY2012	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y11M
CY2010	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P5Y11M
CY2012	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Exercisable Options Weighted Average Remaining Contractual Term2 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2	P4Y7M
CY2012	us-gaap	Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Term2 SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2	P5Y3M
CY2012	us-gaap	Segment Reporting Information Revenue SegmentReportingInformationRevenue	4246400000	USD
CY2010	us-gaap	Segment Reporting Information Revenue SegmentReportingInformationRevenue	4202500000	USD
CY2011	us-gaap	Segment Reporting Information Revenue SegmentReportingInformationRevenue	4486400000	USD
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.039
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.039
CY2012Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	22.19
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	36100000	USD
CY2010	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	62100000	USD
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	47500000	USD
CY2013Q1	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	1418560	shares
CY2010	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	3.36
CY2011	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	3.17
CY2012	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	3.34
CY2012Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	8919669	shares
CY2012Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	23.86
CY2011	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	54400000	USD
CY2010	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	90900000	USD
CY2010	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	5800000	shares
CY2012	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	4300000	shares
CY2011	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	6200000	shares
CY2012	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	153200000	USD
CY2010	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	156600000	USD
CY2011	us-gaap	Stock Repurchased During Period Value StockRepurchasedDuringPeriodValue	193900000	USD
CY2010Q4	us-gaap	Stockholders Equity StockholdersEquity	3802100000	USD
CY2011Q4	us-gaap	Stockholders Equity StockholdersEquity	3963300000	USD
CY2009Q4	us-gaap	Stockholders Equity StockholdersEquity	3566900000	USD
CY2012Q4	us-gaap	Stockholders Equity StockholdersEquity	4135100000	USD
CY2011	us-gaap	Tax Benefit From Stock Options Exercised1 TaxBenefitFromStockOptionsExercised1	14300000	USD
CY2012	us-gaap	Tax Benefit From Stock Options Exercised1 TaxBenefitFromStockOptionsExercised1	0	USD
CY2010	us-gaap	Tax Benefit From Stock Options Exercised1 TaxBenefitFromStockOptionsExercised1	24100000	USD
CY2011Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	25000000	USD
CY2012Q4	us-gaap	Tax Credit Carryforward Amount TaxCreditCarryforwardAmount	41200000	USD
CY2012Q4	us-gaap	Tax Credit Carryforward Deferred Tax Asset TaxCreditCarryforwardDeferredTaxAsset	41200000	USD
CY2011Q4	us-gaap	Tax Credit Carryforward Deferred Tax Asset TaxCreditCarryforwardDeferredTaxAsset	25000000	USD
CY2011	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	113700000	USD
CY2012	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	121400000	USD
CY2010	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	106000000	USD
CY2012	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	0	USD
CY2011	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	0	USD
CY2011Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	11100000	USD
CY2010Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	29500000	USD
CY2012Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	11300000	USD
CY2011	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	13900000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	10600000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2011	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	2000000	USD
CY2012Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued	0	USD
CY2011Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued	0	USD
CY2011	us-gaap	Unrecognized Tax Benefits Income Tax Penalties Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense	300000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Income Tax Penalties Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense	0	USD
CY2010	us-gaap	Unrecognized Tax Benefits Income Tax Penalties Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense	0	USD
CY2012	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	10800000	USD
CY2011	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	0	USD
CY2012Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	300000	USD
CY2011Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	2000000	USD
CY2010	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	4100000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	200000	USD
CY2011	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Expense UnrecognizedTaxBenefitsInterestOnIncomeTaxesExpense	700000	USD
CY2011	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	2500000	USD
CY2012	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	0	USD
CY2012Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	1000000	USD
CY2011Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	100000	USD
CY2012	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	3246100000	USD
CY2010	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	3590500000	USD
CY2011	us-gaap	Utilities Operating Expense UtilitiesOperatingExpense	3599100000	USD
CY2012	us-gaap	Utilities Operating Expense Maintenance And Operations UtilitiesOperatingExpenseMaintenanceAndOperations	1116100000	USD
CY2011	us-gaap	Utilities Operating Expense Maintenance And Operations UtilitiesOperatingExpenseMaintenanceAndOperations	1256800000	USD
CY2010	us-gaap	Utilities Operating Expense Maintenance And Operations UtilitiesOperatingExpenseMaintenanceAndOperations	1327500000	USD
CY2012	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	232800000	shares
CY2010	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	236700000	shares
CY2011	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	235400000	shares
CY2012	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	230200000	shares
CY2011	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	232600000	shares
CY2010	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	233800000	shares
CY2012	wec	Ability To Declare Common Dividends Limited To Percentage Of Net Income AbilityToDeclareCommonDividendsLimitedToPercentageOfNetIncome	limited to 75% or 50%
CY2012Q4	wec	Accrued Revenues AccruedRevenues	278100000	USD
CY2011Q4	wec	Accrued Revenues AccruedRevenues	252700000	USD
CY2009	wec	Increase In Regulatory Asset Due To Minimum Lease Payment IncreaseInRegulatoryAssetDueToMinimumLeasePayment	78500000	USD
CY2012	wec	Debt Securities In Cash Equivalents Maximum Period Until Maturity DebtSecuritiesInCashEquivalentsMaximumPeriodUntilMaturity	P0Y3M
CY2011Q4	wec	Deferred Tax Assets Construction Advances Non Current DeferredTaxAssetsConstructionAdvancesNonCurrent	25400000	USD
CY2012Q4	wec	Deferred Tax Assets Construction Advances Non Current DeferredTaxAssetsConstructionAdvancesNonCurrent	22200000	USD
CY2011Q4	wec	Deferred Tax Assets Employee Benefits And Compensation Current DeferredTaxAssetsEmployeeBenefitsAndCompensationCurrent	14600000	USD
CY2012Q4	wec	Deferred Tax Assets Employee Benefits And Compensation Current DeferredTaxAssetsEmployeeBenefitsAndCompensationCurrent	14900000	USD
CY2011Q4	wec	Deferred Tax Assets Employee Benefits And Compensation Non Current DeferredTaxAssetsEmployeeBenefitsAndCompensationNonCurrent	103600000	USD
CY2012Q4	wec	Deferred Tax Assets Employee Benefits And Compensation Non Current DeferredTaxAssetsEmployeeBenefitsAndCompensationNonCurrent	97000000	USD
CY2012	wec	Capital Lease Agreement With Vie Remaining Term In Years CapitalLeaseAgreementWithVieRemainingTermInYears	10
CY2012	wec	Capital Lease Obligation At End Of Life Of Contract CapitalLeaseObligationAtEndOfLifeOfContract	0	USD
CY2012Q4	wec	Capital Leases Future Minimum Payments Due Less Executory Costs CapitalLeasesFutureMinimumPaymentsDueLessExecutoryCosts	187900000	USD
CY2012	wec	Preferred Interest Rate PreferredInterestRate	0.0360
CY2011	wec	Proceeds From Sale Of Interest In Unit ProceedsFromSaleOfInterestInUnit	38000000	USD
CY2012Q4	wec	Current Pension Plan Asset Allocation In Equity Investments CurrentPensionPlanAssetAllocationInEquityInvestments	0.45
CY2012Q4	wec	Current Pension Plan Asset Allocation In Fixed Income Investments CurrentPensionPlanAssetAllocationInFixedIncomeInvestments	0.55
CY2011Q4	wec	Deferred Tax Assets Future Federal Tax Benefits DeferredTaxAssetsFutureFederalTaxBenefits	328500000	USD
CY2012Q4	wec	Deferred Tax Assets Future Federal Tax Benefits DeferredTaxAssetsFutureFederalTaxBenefits	334700000	USD
CY2012Q4	wec	Deferred Tax Assets Other Current DeferredTaxAssetsOtherCurrent	81100000	USD
CY2011Q4	wec	Deferred Tax Assets Other Current DeferredTaxAssetsOtherCurrent	57100000	USD
CY2011Q4	wec	Deferred Tax Assets Other Non Current DeferredTaxAssetsOtherNonCurrent	35000000	USD
CY2012Q4	wec	Deferred Tax Assets Other Non Current DeferredTaxAssetsOtherNonCurrent	16300000	USD
CY2012Q4	wec	Deferred Tax Assets Uncertainty In Income Taxes DeferredTaxAssetsUncertaintyInIncomeTaxes	10200000	USD
CY2011Q4	wec	Deferred Tax Assets Uncertainty In Income Taxes DeferredTaxAssetsUncertaintyInIncomeTaxes	11000000	USD
CY2011Q4	wec	Deferred Tax Liabilities Deferred Transmission Costs Non Current DeferredTaxLiabilitiesDeferredTransmissionCostsNonCurrent	47400000	USD
CY2012Q4	wec	Deferred Tax Liabilities Deferred Transmission Costs Non Current DeferredTaxLiabilitiesDeferredTransmissionCostsNonCurrent	45700000	USD
CY2011Q4	wec	Deferred Tax Liabilities Employee Benefits And Compensation Non Current DeferredTaxLiabilitiesEmployeeBenefitsAndCompensationNonCurrent	232800000	USD
CY2012Q4	wec	Deferred Tax Liabilities Employee Benefits And Compensation Non Current DeferredTaxLiabilitiesEmployeeBenefitsAndCompensationNonCurrent	244300000	USD
CY2012Q4	wec	Deferred Tax Liabilities Investment In Transmission Affiliate Non Current DeferredTaxLiabilitiesInvestmentInTransmissionAffiliateNonCurrent	144900000	USD
CY2011Q4	wec	Deferred Tax Liabilities Investment In Transmission Affiliate Non Current DeferredTaxLiabilitiesInvestmentInTransmissionAffiliateNonCurrent	129200000	USD
CY2011Q4	wec	Deferred Tax Liabilities Other Non Current DeferredTaxLiabilitiesOtherNonCurrent	66500000	USD
CY2012Q4	wec	Deferred Tax Liabilities Other Non Current DeferredTaxLiabilitiesOtherNonCurrent	91200000	USD
CY2012Q4	wec	Deferred Tax Liabilities Prepaid Items Current DeferredTaxLiabilitiesPrepaidItemsCurrent	49700000	USD
CY2011Q4	wec	Deferred Tax Liabilities Prepaid Items Current DeferredTaxLiabilitiesPrepaidItemsCurrent	50100000	USD
CY2011	wec	Effective Income Tax Rate Reconciliation Allowance For Funds Used During Construction Capitalized Cost Of Equity EffectiveIncomeTaxRateReconciliationAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	-0.027
CY2012	wec	Effective Income Tax Rate Reconciliation Allowance For Funds Used During Construction Capitalized Cost Of Equity EffectiveIncomeTaxRateReconciliationAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	-0.014
CY2010	wec	Effective Income Tax Rate Reconciliation Allowance For Funds Used During Construction Capitalized Cost Of Equity EffectiveIncomeTaxRateReconciliationAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	-0.016
CY2011	wec	Effective Income Tax Rate Reconciliation State And Local Income Taxes Net Of Federal Tax Benefit EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxesNetOfFederalTaxBenefit	0.052
CY2010	wec	Effective Income Tax Rate Reconciliation State And Local Income Taxes Net Of Federal Tax Benefit EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxesNetOfFederalTaxBenefit	0.051
CY2012	wec	Effective Income Tax Rate Reconciliation State And Local Income Taxes Net Of Federal Tax Benefit EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxesNetOfFederalTaxBenefit	0.051
CY2012	wec	Exercise Price Of Stock Option On Grant Date ExercisePriceOfStockOptionOnGrantDate	no less than 100% of the common stock's fair market value
CY2012Q4	wec	Fair Value Assets Measured On Recurring Basis Total Assets FairValueAssetsMeasuredOnRecurringBasisTotalAssets	20600000	USD
CY2011Q4	wec	Fair Value Assets Measured On Recurring Basis Total Assets FairValueAssetsMeasuredOnRecurringBasisTotalAssets	66100000	USD
CY2012Q4	wec	Fair Value Liabilities Measured On Recurring Basis Total Liabilities FairValueLiabilitiesMeasuredOnRecurringBasisTotalLiabilities	500000	USD
CY2011Q4	wec	Fair Value Liabilities Measured On Recurring Basis Total Liabilities FairValueLiabilitiesMeasuredOnRecurringBasisTotalLiabilities	9200000	USD
CY2011	wec	Fuel And Purchased Power FuelAndPurchasedPower	1169700000	USD
CY2012	wec	Fuel And Purchased Power FuelAndPurchasedPower	1098600000	USD
CY2010	wec	Fuel And Purchased Power FuelAndPurchasedPower	1099900000	USD
CY2012	wec	Fuel Cost Tolerance Range Set By Regulators Percent FuelCostToleranceRangeSetByRegulatorsPercent	0.02
CY2012	wec	Health Care Cost Trend Rate Post Specified Age HealthCareCostTrendRatePostSpecifiedAge	65
CY2012	wec	Health Care Cost Trend Rate Up To Specified Age HealthCareCostTrendRateUpToSpecifiedAge	65
CY2011	wec	Income Tax Expense Benefit Effective Tax Rate IncomeTaxExpenseBenefitEffectiveTaxRate	0.340
CY2010	wec	Income Tax Expense Benefit Effective Tax Rate IncomeTaxExpenseBenefitEffectiveTaxRate	0.355
CY2012	wec	Income Tax Expense Benefit Effective Tax Rate IncomeTaxExpenseBenefitEffectiveTaxRate	0.359
CY2012	wec	Income Tax Reconciliation Allowance For Funds Used During Construction Capitalized Cost Of Equity IncomeTaxReconciliationAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	12300000	USD
CY2010	wec	Income Tax Reconciliation Allowance For Funds Used During Construction Capitalized Cost Of Equity IncomeTaxReconciliationAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	11400000	USD
CY2011	wec	Income Tax Reconciliation Allowance For Funds Used During Construction Capitalized Cost Of Equity IncomeTaxReconciliationAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	20800000	USD
CY2011	wec	Matching Contributions Under Savings Plans MatchingContributionsUnderSavingsPlans	14100000	USD
CY2010	wec	Matching Contributions Under Savings Plans MatchingContributionsUnderSavingsPlans	13800000	USD
CY2012	wec	Matching Contributions Under Savings Plans MatchingContributionsUnderSavingsPlans	13800000	USD
CY2012	wec	Maximum Duration To Recover Outstanding Regulatory Assets MaximumDurationToRecoverOutstandingRegulatoryAssets	P8Y
CY2012	wec	Maximum Percentage Award Based On Performance Unit MaximumPercentageAwardBasedOnPerformanceUnit	1.75
CY2012	wec	Maximum Regulatory Current Assets And Current Liabilities Amortization Period MaximumRegulatoryCurrentAssetsAndCurrentLiabilitiesAmortizationPeriod	1
CY2012	wec	Minimum Duration To Recover Outstanding Regulatory Assets MinimumDurationToRecoverOutstandingRegulatoryAssets	P1Y
CY2012	wec	Minimum Energy Requirement In Gas Fired Cogeneration Facility MinimumEnergyRequirementInGasFiredCogenerationFacility	0
CY2012	wec	Minimum Percentage Award Based On Performance Unit MinimumPercentageAwardBasedOnPerformanceUnit	0.00
CY2012Q4	wec	Number Of Series Of Tax Exempt Pollution Control Refunding Bonds NumberOfSeriesOfTaxExemptPollutionControlRefundingBonds	2
CY2010	wec	Other Income And Deductions Net Other OtherIncomeAndDeductionsNetOther	3300000	USD
CY2012	wec	Other Income And Deductions Net Other OtherIncomeAndDeductionsNetOther	-3200000	USD
CY2011	wec	Other Income And Deductions Net Other OtherIncomeAndDeductionsNetOther	900000	USD
CY2012Q4	wec	Other Post Retirement Employee Benefits Asset Allocation In Equity Investments OtherPostRetirementEmployeeBenefitsAssetAllocationInEquityInvestments	0.60
CY2012Q4	wec	Other Post Retirement Employee Benefits Asset Allocation In Fixed Income Investments OtherPostRetirementEmployeeBenefitsAssetAllocationInFixedIncomeInvestments	0.40
CY2012Q4	wec	Percentage Of Equity Method Investment Exceeding Consolidated Net Assets PercentageOfEquityMethodInvestmentExceedingConsolidatedNetAssets	0.25
CY2012	wec	Power Capacity Under Capital Lease PowerCapacityUnderCapitalLease	236
CY2012	wec	Power Purchase Contract Expected Future Renewable Period PowerPurchaseContractExpectedFutureRenewablePeriod	10
CY2012	wec	Power Purchase Contract Period PowerPurchaseContractPeriod	25
CY2011Q4	wec	Property Related Deferred Tax Assets Non Current PropertyRelatedDeferredTaxAssetsNonCurrent	28300000	USD
CY2012Q4	wec	Property Related Deferred Tax Assets Non Current PropertyRelatedDeferredTaxAssetsNonCurrent	28300000	USD
CY2012	wec	Regulatory Asset Value At End Of Life Of Contract RegulatoryAssetValueAtEndOfLifeOfContract	0	USD
CY2012	wec	Regulatory Current Assets And Liabilities Amortization Period RegulatoryCurrentAssetsAndLiabilitiesAmortizationPeriod	within one year
CY2011	wec	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Forfeiture Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRate	0.020
CY2012	wec	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Forfeiture Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRate	0.020
CY2010	wec	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Forfeiture Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRate	0.020
CY2012Q4	wec	Significant Decrease In Unrecognized Tax Benefits Reasonably Possibly SignificantDecreaseInUnrecognizedTaxBenefitsReasonablyPossibly	-1400000	USD
CY2012	wec	Stock Equity To Total Capitalization StockEquityToTotalCapitalization	is less than 25% and 20%
CY2011Q4	wec	Total Capitalization TotalCapitalization	8608000000	USD
CY2012Q4	wec	Total Capitalization TotalCapitalization	8619300000	USD
CY2011Q4	wec	Total Deferred Charges And Other Assets TotalDeferredChargesAndOtherAssets	1882200000	USD
CY2012Q4	wec	Total Deferred Charges And Other Assets TotalDeferredChargesAndOtherAssets	1985100000	USD
CY2012Q4	wec	Total Deferred Credits And Other Liabilities TotalDeferredCreditsAndOtherLiabilities	4222400000	USD
CY2011Q4	wec	Total Deferred Credits And Other Liabilities TotalDeferredCreditsAndOtherLiabilities	3889600000	USD
CY2012	dei	Amendment Flag AmendmentFlag	false
CY2012	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2012	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2012	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2012
CY2012	dei	Document Period End Date DocumentPeriodEndDate	2012-12-31
CY2012	dei	Document Type DocumentType	10-K
CY2012	dei	Entity Central Index Key EntityCentralIndexKey	0000783325
CY2013Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	229005057	shares
CY2012	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2012	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2012Q2	dei	Entity Public Float EntityPublicFloat	9100000000	USD
CY2012	dei	Entity Registrant Name EntityRegistrantName	WISCONSIN ENERGY CORP
CY2012	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2012	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes

Files In Submission

Name	View Source	Status
0000107815-13-000055-index-headers.html	Edgar Link	pending
0000107815-13-000055-index.html	Edgar Link	pending
0000107815-13-000055.txt	Edgar Link	pending
0000107815-13-000055-xbrl.zip	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xls	Edgar Link	pending
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report.css	Edgar Link	pending
Show.js	Edgar Link	pending
wec-20121231.xml	Edgar Link	completed
wec-20121231.xsd	Edgar Link	pending
wec-20121231_cal.xml	Edgar Link	unprocessable
wec-20121231_def.xml	Edgar Link	unprocessable
wec-20121231_lab.xml	Edgar Link	unprocessable
wec-20121231_pre.xml	Edgar Link	unprocessable
wec1231201210-k.htm	Edgar Link	pending
wec12312012ex1018.htm	Edgar Link	pending
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wec12312012ex321.htm	Edgar Link	pending
wec12312012ex322.htm	Edgar Link	pending
weclogo.jpg	Edgar Link	pending

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$WEC
WEC ENERGY GROUP, INC. Stock $wec

2011 Q4 Form 10-K Financial Statement

#000010781513000055 Filed on February 27, 2013

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WEC WEC ENERGY GROUP, INC. Stock $wec

2011 Q4 Form 10-K Financial Statement

#000010781513000055 Filed on February 27, 2013

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WEC
WEC ENERGY GROUP, INC. Stock $wec