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Consolidated Statements of Income (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Revenues      
Vertically Integrated Utilities $ 9,397,000,000us-gaap_ElectricUtilityRevenue $ 9,347,000,000us-gaap_ElectricUtilityRevenue $ 8,785,000,000us-gaap_ElectricUtilityRevenue
Transmission and Distribution Utilities 4,553,000,000us-gaap_ElectricalTransmissionAndDistributionRevenue 4,279,000,000us-gaap_ElectricalTransmissionAndDistributionRevenue 4,659,000,000us-gaap_ElectricalTransmissionAndDistributionRevenue
Generation and Marketing 2,384,000,000us-gaap_ElectricalGenerationRevenue 1,208,000,000us-gaap_ElectricalGenerationRevenue 882,000,000us-gaap_ElectricalGenerationRevenue
Other Revenues 686,000,000us-gaap_OtherSalesRevenueNet 523,000,000us-gaap_OtherSalesRevenueNet 619,000,000us-gaap_OtherSalesRevenueNet
TOTAL REVENUES 17,020,000,000us-gaap_Revenues 15,357,000,000us-gaap_Revenues 14,945,000,000us-gaap_Revenues
Expenses      
Fuel and Other Consumables Used for Electric Generation 4,272,000,000us-gaap_ElectricProductionExpense 4,068,000,000us-gaap_ElectricProductionExpense 4,111,000,000us-gaap_ElectricProductionExpense
Purchased Electricity for Resale 2,086,000,000us-gaap_CostOfPurchasedPower 1,491,000,000us-gaap_CostOfPurchasedPower 1,169,000,000us-gaap_CostOfPurchasedPower
Other Operation 3,225,000,000us-gaap_UtilitiesOperatingExpenseOperations 2,904,000,000us-gaap_UtilitiesOperatingExpenseOperations 2,962,000,000us-gaap_UtilitiesOperatingExpenseOperations
Maintenance 1,361,000,000us-gaap_UtilitiesOperatingExpenseMaintenance 1,179,000,000us-gaap_UtilitiesOperatingExpenseMaintenance 1,115,000,000us-gaap_UtilitiesOperatingExpenseMaintenance
Asset Impairments and Other Related Charges 0us-gaap_OtherAssetImpairmentCharges 226,000,000us-gaap_OtherAssetImpairmentCharges 300,000,000us-gaap_OtherAssetImpairmentCharges
Depreciation and Amortization 1,929,000,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization 1,743,000,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization 1,782,000,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
Taxes Other Than Income Taxes 915,000,000us-gaap_TaxesExcludingIncomeAndExciseTaxes 891,000,000us-gaap_TaxesExcludingIncomeAndExciseTaxes 850,000,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
TOTAL EXPENSES 13,788,000,000us-gaap_OperatingExpenses 12,502,000,000us-gaap_OperatingExpenses 12,289,000,000us-gaap_OperatingExpenses
OPERATING INCOME (LOSS) 3,232,000,000us-gaap_OperatingIncomeLoss 2,855,000,000us-gaap_OperatingIncomeLoss 2,656,000,000us-gaap_OperatingIncomeLoss
Other Income (Expense):      
Interest and Investment Income 7,000,000us-gaap_InvestmentIncomeNet 58,000,000us-gaap_InvestmentIncomeNet 8,000,000us-gaap_InvestmentIncomeNet
Carrying Costs Income 33,000,000aep_CarryingCostsIncome 30,000,000aep_CarryingCostsIncome 53,000,000aep_CarryingCostsIncome
Allowance for Equity Funds Used During Construction 103,000,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity 73,000,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity 93,000,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
Interest Expense (885,000,000)us-gaap_InterestExpense (906,000,000)us-gaap_InterestExpense (988,000,000)us-gaap_InterestExpense
INCOME BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS) 2,490,000,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments 2,110,000,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments 1,822,000,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
Income Tax Expense (Credit) 942,000,000us-gaap_IncomeTaxExpenseBenefit 684,000,000us-gaap_IncomeTaxExpenseBenefit 604,000,000us-gaap_IncomeTaxExpenseBenefit
Equity Earnings (Loss) of Unconsolidated Subsidiaries 90,000,000us-gaap_IncomeLossFromEquityMethodInvestments 58,000,000us-gaap_IncomeLossFromEquityMethodInvestments 44,000,000us-gaap_IncomeLossFromEquityMethodInvestments
NET INCOME (LOSS) 1,638,000,000us-gaap_ProfitLoss 1,484,000,000us-gaap_ProfitLoss 1,262,000,000us-gaap_ProfitLoss
Net Income Attributable to Noncontrolling Interests 4,000,000us-gaap_NetIncomeLossAttributableToNoncontrollingInterest 4,000,000us-gaap_NetIncomeLossAttributableToNoncontrollingInterest 3,000,000us-gaap_NetIncomeLossAttributableToNoncontrollingInterest
EARNINGS ATTRIBUTABLE TO COMMON SHAREHOLDERS 1,634,000,000us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic 1,480,000,000us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic 1,259,000,000us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
Earnings Per Share      
WEIGHTED AVERAGE NUMBER OF BASIC AEP COMMON SHARES OUTSTANDING 488,592,997us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 486,619,555us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 484,682,469us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
TOTAL BASIC EARNINGS PER SHARE ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS $ 3.34us-gaap_EarningsPerShareBasic $ 3.04us-gaap_EarningsPerShareBasic $ 2.60us-gaap_EarningsPerShareBasic
WEIGHTED AVERAGE NUMBER OF DILUTED AEP COMMON SHARES OUTSTANDING 488,899,840us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 487,040,956us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 485,084,694us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
TOTAL DILUTED EARNINGS PER SHARE ATTRIBUTABLE TO AEP COMMON SHAREHOLDERS $ 3.34us-gaap_EarningsPerShareDiluted $ 3.04us-gaap_EarningsPerShareDiluted $ 2.60us-gaap_EarningsPerShareDiluted
Appalachian Power Co [Member]      
Revenues      
Vertically Integrated Utilities 2,899,402,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
3,059,577,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
2,948,762,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Sales to AEP Affiliates 144,437,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
347,484,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
318,199,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Other Revenues 9,239,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
10,345,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
9,970,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
TOTAL REVENUES 3,053,078,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
3,417,406,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
3,276,931,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Expenses      
Fuel and Other Consumables Used for Electric Generation 813,399,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
769,853,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
815,979,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Purchased Electricity for Resale 456,622,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
232,702,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
211,133,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Purchased Electricity from AEP Affiliates 4,661,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
830,959,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
661,238,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Other Operation 427,726,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
311,975,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
332,936,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Maintenance 259,348,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
273,164,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
211,702,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Asset Impairments and Other Related Charges 0us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
39,283,000us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
0us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Depreciation and Amortization 400,882,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
342,643,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
344,293,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Taxes Other Than Income Taxes 122,254,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
110,549,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
102,190,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
TOTAL EXPENSES 2,484,892,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
2,911,128,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
2,679,471,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
OPERATING INCOME (LOSS) 568,186,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
506,278,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
597,460,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Other Income (Expense):      
Interest Income 1,629,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
2,411,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
1,358,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Carrying Costs Income 3,045,000aep_CarryingCostsIncome
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
8,086,000aep_CarryingCostsIncome
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
24,602,000aep_CarryingCostsIncome
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Allowance for Equity Funds Used During Construction 7,053,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
2,353,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
1,684,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Interest Expense (209,570,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
(192,982,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
(202,074,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
INCOME BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS) 370,343,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
326,146,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
423,030,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Income Tax Expense (Credit) 154,928,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
132,935,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
165,527,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
NET INCOME (LOSS) 215,415,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
193,211,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
257,503,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_AppalachianPowerCoMember
Indiana Michigan Power Co [Member]      
Revenues      
Vertically Integrated Utilities 2,149,109,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
2,022,257,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
1,810,069,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Sales to AEP Affiliates 4,198,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
219,399,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
268,408,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Other Revenues - Affiliated 94,379,000us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
122,287,000us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
117,052,000us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Other Revenues 2,048,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
2,916,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
4,582,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
TOTAL REVENUES 2,249,734,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
2,366,859,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
2,200,111,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Expenses      
Fuel and Other Consumables Used for Electric Generation 476,628,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
434,078,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
464,420,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Purchased Electricity for Resale 96,813,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
151,404,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
117,860,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Purchased Electricity from AEP Affiliates 269,972,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
433,209,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
386,404,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Other Operation 585,958,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
564,012,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
583,865,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Maintenance 228,506,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
195,892,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
172,562,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Depreciation and Amortization 200,196,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
177,727,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
146,619,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Taxes Other Than Income Taxes 86,419,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
88,676,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
80,687,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
TOTAL EXPENSES 1,944,492,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
2,044,998,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
1,952,417,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
OPERATING INCOME (LOSS) 305,242,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
321,861,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
247,694,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Other Income (Expense):      
Interest Income 4,628,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
8,521,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
3,122,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Allowance for Equity Funds Used During Construction 18,873,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
19,943,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
9,724,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Interest Expense (93,475,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
(97,710,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
(102,739,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
INCOME BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS) 235,268,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
252,615,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
157,801,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Income Tax Expense (Credit) 79,621,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
75,111,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
39,344,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
NET INCOME (LOSS) 155,647,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
177,504,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
118,457,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_IndianaMichiganPowerCoMember
Ohio Power Co [Member]      
Revenues      
Transmission and Distribution Utilities 3,204,926,000us-gaap_ElectricalTransmissionAndDistributionRevenue
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
3,562,224,000us-gaap_ElectricalTransmissionAndDistributionRevenue
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
4,022,116,000us-gaap_ElectricalTransmissionAndDistributionRevenue
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Sales to AEP Affiliates 165,216,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
1,166,854,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
847,294,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Other Revenues - Affiliated 0us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
18,140,000us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
39,401,000us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Other Revenues 6,778,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
15,397,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
19,385,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
TOTAL REVENUES 3,376,920,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
4,762,615,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
4,928,196,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Expenses      
Fuel and Other Consumables Used for Electric Generation 0us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
1,496,856,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
1,471,316,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Purchased Electricity for Resale 282,000,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
151,561,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
205,845,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Purchased Electricity from AEP Affiliates 1,192,700,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
349,732,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
380,706,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Amortization of Generation Deferrals 110,942,000aep_AmortizationOfGenerationDeferrals
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
0aep_AmortizationOfGenerationDeferrals
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
0aep_AmortizationOfGenerationDeferrals
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Other Operation 594,776,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
707,953,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
669,981,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Maintenance 195,964,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
319,625,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
319,324,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Asset Impairments and Other Related Charges 0us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
154,304,000us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
287,031,000us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Depreciation and Amortization 213,669,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
382,570,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
511,070,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Taxes Other Than Income Taxes 353,364,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
406,916,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
405,976,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
TOTAL EXPENSES 2,943,415,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
3,969,517,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
4,251,249,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
OPERATING INCOME (LOSS) 433,505,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
793,098,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
676,947,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Other Income (Expense):      
Interest Income 9,956,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
3,325,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
3,536,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Carrying Costs Income 26,546,000aep_CarryingCostsIncome
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
16,312,000aep_CarryingCostsIncome
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
16,942,000aep_CarryingCostsIncome
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Allowance for Equity Funds Used During Construction 6,913,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
4,961,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
3,492,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Interest Expense (128,291,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
(182,046,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
(213,100,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
INCOME BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS) 348,629,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
635,650,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
487,817,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Income Tax Expense (Credit) 132,207,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
225,670,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
144,283,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
NET INCOME (LOSS) 216,422,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
409,980,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
343,534,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_OhioPowerCoMember
Public Service Co Of Oklahoma [Member]      
Revenues      
Vertically Integrated Utilities 1,340,307,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
1,277,711,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
1,206,583,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Sales to AEP Affiliates 7,054,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
14,246,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
22,603,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Other Revenues 4,215,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
3,565,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
3,752,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
TOTAL REVENUES 1,351,576,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
1,295,522,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
1,232,938,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Expenses      
Fuel and Other Consumables Used for Electric Generation 257,996,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
327,829,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
310,296,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Purchased Electricity for Resale 385,029,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
246,109,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
208,676,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Purchased Electricity from AEP Affiliates 11,024,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
36,891,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
24,378,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Other Operation 262,804,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
225,500,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
213,195,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Maintenance 107,952,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
107,076,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
106,835,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Depreciation and Amortization 100,977,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
95,667,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
95,180,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Taxes Other Than Income Taxes 36,962,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
45,215,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
43,428,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
TOTAL EXPENSES 1,162,744,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
1,084,287,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
1,001,988,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
OPERATING INCOME (LOSS) 188,832,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
211,235,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
230,950,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Other Income (Expense):      
Interest Income 249,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
1,096,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
1,308,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Carrying Costs Income 0aep_CarryingCostsIncome
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
338,000aep_CarryingCostsIncome
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
1,856,000aep_CarryingCostsIncome
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Allowance for Equity Funds Used During Construction 3,071,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
4,187,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
2,007,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Interest Expense (54,641,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
(53,175,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
(55,286,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
INCOME BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS) 137,511,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
163,681,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
180,835,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Income Tax Expense (Credit) 50,582,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
65,885,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
66,694,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
NET INCOME (LOSS) 86,929,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
97,796,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
114,141,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_PublicServiceCoOfOklahomaMember
Southwestern Electric Power Co [Member]      
Revenues      
Vertically Integrated Utilities 1,817,863,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
1,742,575,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
1,538,533,000us-gaap_ElectricUtilityRevenue
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Sales to AEP Affiliates 26,278,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
51,812,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
37,441,000us-gaap_RevenueFromRelatedParties
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Other Revenues 2,256,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
1,416,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
1,860,000us-gaap_OtherSalesRevenueNet
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
TOTAL REVENUES 1,846,397,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
1,795,803,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
1,577,834,000us-gaap_Revenues
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Expenses      
Fuel and Other Consumables Used for Electric Generation 650,437,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
630,503,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
579,721,000us-gaap_ElectricProductionExpense
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Purchased Electricity for Resale 178,105,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
169,954,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
131,706,000us-gaap_CostOfPurchasedPower
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Purchased Electricity from AEP Affiliates 3,766,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
11,172,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
19,229,000aep_CostOfPurchasedPowerFromAffiliate
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Other Operation 272,785,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
250,676,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
230,078,000us-gaap_UtilitiesOperatingExpenseOperations
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Maintenance 149,243,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
129,742,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
117,415,000us-gaap_UtilitiesOperatingExpenseMaintenance
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Asset Impairments and Other Related Charges 0us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
0us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
13,000,000us-gaap_OtherAssetImpairmentCharges
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Depreciation and Amortization 185,134,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
179,251,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
138,778,000us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Taxes Other Than Income Taxes 84,285,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
80,662,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
72,011,000us-gaap_TaxesExcludingIncomeAndExciseTaxes
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
TOTAL EXPENSES 1,523,755,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
1,451,960,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
1,301,938,000us-gaap_OperatingExpenses
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
OPERATING INCOME (LOSS) 322,642,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
343,843,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
275,896,000us-gaap_OperatingIncomeLoss
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Other Income (Expense):      
Interest Income 299,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
58,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
1,230,000us-gaap_InvestmentIncomeInterestAndDividend
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Allowance for Equity Funds Used During Construction 11,947,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
7,338,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
57,054,000us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Interest Expense (126,127,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
(130,282,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
(88,318,000)us-gaap_InterestExpense
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
INCOME BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS) 208,761,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
220,957,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
245,862,000us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Income Tax Expense (Credit) 66,420,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
69,461,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
45,858,000us-gaap_IncomeTaxExpenseBenefit
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Equity Earnings (Loss) of Unconsolidated Subsidiaries 2,218,000us-gaap_IncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
2,323,000us-gaap_IncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
2,509,000us-gaap_IncomeLossFromEquityMethodInvestments
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
NET INCOME (LOSS) 144,559,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
153,819,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
202,513,000us-gaap_ProfitLoss
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
Net Income Attributable to Noncontrolling Interests 4,190,000us-gaap_NetIncomeLossAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
4,008,000us-gaap_NetIncomeLossAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
3,622,000us-gaap_NetIncomeLossAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
EARNINGS ATTRIBUTABLE TO COMMON SHAREHOLDERS $ 140,369,000us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
$ 149,811,000us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember
$ 198,891,000us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
/ dei_LegalEntityAxis
= aep_SouthwesternElectricPowerCoMember