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Fair Value Assets and Liabilities (Details) (USD $)
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Dec. 31, 2012
Assets:      
Cash and Cash Equivalents $ 179,000,000 [1]   $ 279,000,000 [1]
Other Temporary Investments 261,000,000   324,000,000
Risk Management Assets      
Risk Management Assets 503,000,000   559,000,000
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 1,788,000,000   1,706,000,000
Total Assets 2,731,000,000   2,868,000,000
Liabilities:      
Risk Management Liabilities 279,000,000   369,000,000
Changes in the Fair Value of Net Trading Derivatives and other investments      
Beginning Balance 86,000,000 69,000,000  
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) (4,000,000) [2],[3] (12,000,000) [2],[3]  
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date (5,000,000) [2] 3,000,000 [2]  
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 1,000,000 1,000,000  
Purchases, Issuances and Settlements (6,000,000) [4] 16,000,000 [4]  
Transfers into Level 3 6,000,000 [5],[6] 17,000,000 [5],[6]  
Transfers out of Level 3 0 [6],[7] (12,000,000) [6],[7]  
Changes in Fair Value Allocated to Regulated Jurisdictions (2,000,000) [8] 10,000,000 [8]  
Ending Balance 76,000,000 92,000,000  
Level 3 Quantitative Information [Abstract]      
Counterparty Credit Risk 354 [9]    
Level 1 [Member]
      
Assets:      
Cash and Cash Equivalents 6,000,000 [1]   6,000,000 [1]
Other Temporary Investments 245,000,000   310,000,000
Risk Management Assets      
Risk Management Assets 47,000,000   55,000,000
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 821,000,000   743,000,000
Total Assets 1,119,000,000   1,114,000,000
Liabilities:      
Risk Management Liabilities 45,000,000   45,000,000
Level 2 [Member]
      
Assets:      
Cash and Cash Equivalents 1,000,000 [1]   1,000,000 [1]
Other Temporary Investments 6,000,000   5,000,000
Risk Management Assets      
Risk Management Assets 852,000,000   968,000,000
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 958,000,000   953,000,000
Total Assets 1,817,000,000   1,927,000,000
Liabilities:      
Risk Management Liabilities 728,000,000   925,000,000
Level 3 [Member]
      
Assets:      
Cash and Cash Equivalents 0 [1]   0 [1]
Other Temporary Investments 0   0
Risk Management Assets      
Risk Management Assets 118,000,000   131,000,000
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Total Assets 118,000,000   131,000,000
Liabilities:      
Risk Management Liabilities 42,000,000   45,000,000
Fair Value Inputs Other [Member]
      
Assets:      
Cash and Cash Equivalents 172,000,000 [1]   272,000,000 [1]
Other Temporary Investments 10,000,000   9,000,000
Risk Management Assets      
Risk Management Assets (514,000,000)   (595,000,000)
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 9,000,000   10,000,000
Total Assets (323,000,000)   (304,000,000)
Liabilities:      
Risk Management Liabilities (536,000,000)   (646,000,000)
2013 [Member] | Level 1 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities 6,000,000   9,000,000
2013 [Member] | Level 2 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities 17,000,000   16,000,000
2013 [Member] | Level 3 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities 6,000,000   18,000,000
2014 - 2016 [Member] | Level 1 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities (4,000,000)   (3,000,000)
2014 - 2016 [Member] | Level 2 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities 73,000,000   61,000,000
2014 - 2016 [Member] | Level 3 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities 27,000,000   31,000,000
2017 - 2018 [Member] | Level 1 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities (3,000,000)   (4,000,000)
2017 - 2018 [Member] | Level 2 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities 14,000,000   16,000,000
2017 - 2018 [Member] | Level 3 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities 18,000,000   13,000,000
2019 - 2030 [Member] | Level 2 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities 6,000,000   7,000,000
2019 - 2030 [Member] | Level 3 [Member]
      
Fair Value Measurements 1 (Textuals) [Abstract]      
Maturity of Net Fair Value of Risk Management Contracts Prior to Cash Collateral, Assets/Liabilities 24,000,000   24,000,000
Risk Management Commodity Contracts [Member]
      
Risk Management Assets      
Risk Management Assets 463,000,000 [10],[11]   517,000,000 [10],[12]
Liabilities:      
Risk Management Liabilities 268,000,000 [10],[11]   292,000,000 [10],[12]
Risk Management Commodity Contracts [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 43,000,000 [10],[11]   47,000,000 [10],[12]
Liabilities:      
Risk Management Liabilities 44,000,000 [10],[11]   45,000,000 [10],[12]
Risk Management Commodity Contracts [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 810,000,000 [10],[11]   938,000,000 [10],[12]
Liabilities:      
Risk Management Liabilities 700,000,000 [10],[11]   838,000,000 [10],[12]
Risk Management Commodity Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 117,000,000 [10],[11]   131,000,000 [10],[12]
Liabilities:      
Risk Management Liabilities 42,000,000 [10],[11]   45,000,000 [10],[12]
Risk Management Commodity Contracts [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (507,000,000) [10],[11]   (599,000,000) [10],[12]
Liabilities:      
Risk Management Liabilities (518,000,000) [10],[11]   (636,000,000) [10],[12]
Energy Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 114,000,000    
Liabilities:      
Risk Management Liabilities 37,000,000    
Level 3 Quantitative Information [Abstract]      
Forward Price Range Low 11.59 [13]    
Forward Price Range High 133.27 [13]    
FTRs [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 4,000,000    
Liabilities:      
Risk Management Liabilities 5,000,000    
Level 3 Quantitative Information [Abstract]      
Forward Price Range Low (13.65) [13]    
Forward Price Range High 9.67 [13]    
Commodity Hedges [Member]
      
Risk Management Assets      
Risk Management Assets 24,000,000 [10]   24,000,000 [10]
Liabilities:      
Risk Management Liabilities 4,000,000 [10]   36,000,000 [10]
Commodity Hedges [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 4,000,000 [10]   8,000,000 [10]
Liabilities:      
Risk Management Liabilities 1,000,000 [10]   0 [10]
Commodity Hedges [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 40,000,000 [10]   28,000,000 [10]
Liabilities:      
Risk Management Liabilities 24,000,000 [10]   48,000,000 [10]
Commodity Hedges [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 1,000,000 [10]   0 [10]
Liabilities:      
Risk Management Liabilities 0 [10]   0 [10]
Commodity Hedges [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (21,000,000) [10]   (12,000,000) [10]
Liabilities:      
Risk Management Liabilities (21,000,000) [10]   (12,000,000) [10]
Interest Rate Foreign Currency Hedges [Member]
      
Liabilities:      
Risk Management Liabilities 2,000,000   37,000,000
Interest Rate Foreign Currency Hedges [Member] | Level 1 [Member]
      
Liabilities:      
Risk Management Liabilities 0   0
Interest Rate Foreign Currency Hedges [Member] | Level 2 [Member]
      
Liabilities:      
Risk Management Liabilities 2,000,000   37,000,000
Interest Rate Foreign Currency Hedges [Member] | Level 3 [Member]
      
Liabilities:      
Risk Management Liabilities 0   0
Interest Rate Foreign Currency Hedges [Member] | Fair Value Inputs Other [Member]
      
Liabilities:      
Risk Management Liabilities 0   0
Fair Value Hedges [Member]
      
Risk Management Assets      
Risk Management Assets 5,000,000   4,000,000
Liabilities:      
Risk Management Liabilities 5,000,000   4,000,000
Fair Value Hedges [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0   0
Liabilities:      
Risk Management Liabilities 0   0
Fair Value Hedges [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 2,000,000   2,000,000
Liabilities:      
Risk Management Liabilities 2,000,000   2,000,000
Fair Value Hedges [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0   0
Liabilities:      
Risk Management Liabilities 0   0
Fair Value Hedges [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets 3,000,000   2,000,000
Liabilities:      
Risk Management Liabilities 3,000,000   2,000,000
Appalachian Power Co [Member]
      
Risk Management Assets      
Risk Management Assets 47,143,000   65,320,000
Liabilities:      
Risk Management Liabilities 24,812,000   35,174,000
Changes in the Fair Value of Net Trading Derivatives and other investments      
Beginning Balance 10,979,000 1,971,000  
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) (1,456,000) (3,580,000)  
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date 0 0  
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 0 49,000  
Purchases, Issuances and Settlements 257,000 5,948,000  
Transfers into Level 3 632,000 [5],[6] 2,508,000 [5],[6]  
Transfers out of Level 3 (533,000) [6],[7] (4,001,000) [6],[7]  
Changes in Fair Value Allocated to Regulated Jurisdictions (1,123,000) [8] 5,086,000 [8]  
Ending Balance 8,756,000 7,981,000  
Appalachian Power Co [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 3,184,000   4,161,000
Liabilities:      
Risk Management Liabilities 1,541,000   1,959,000
Appalachian Power Co [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 110,123,000   167,414,000
Liabilities:      
Risk Management Liabilities 101,242,000   160,216,000
Appalachian Power Co [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 13,220,000   17,058,000
Liabilities:      
Risk Management Liabilities 4,464,000   6,079,000
Appalachian Power Co [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (79,384,000)   (123,313,000)
Liabilities:      
Risk Management Liabilities (82,435,000)   (133,080,000)
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member]
      
Risk Management Assets      
Risk Management Assets 46,156,000 [10],[14]   65,018,000 [10],[14]
Liabilities:      
Risk Management Liabilities 24,362,000 [10],[14]   33,819,000 [10],[14]
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 3,184,000 [10],[14]   4,161,000 [10],[14]
Liabilities:      
Risk Management Liabilities 1,541,000 [10],[14]   1,959,000 [10],[14]
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 108,817,000 [10],[14]   166,916,000 [10],[14]
Liabilities:      
Risk Management Liabilities 100,473,000 [10],[14]   158,665,000 [10],[14]
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 13,220,000 [10],[14]   17,058,000 [10],[14]
Liabilities:      
Risk Management Liabilities 4,464,000 [10],[14]   6,079,000 [10],[14]
Appalachian Power Co [Member] | Risk Management Commodity Contracts [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (79,065,000) [10],[14]   (123,117,000) [10],[14]
Liabilities:      
Risk Management Liabilities (82,116,000) [10],[14]   (132,884,000) [10],[14]
Appalachian Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 12,347,000    
Liabilities:      
Risk Management Liabilities 3,082,000    
Level 3 Quantitative Information [Abstract]      
Forward Price Range Low 11.59    
Forward Price Range High 75.95    
Appalachian Power Co [Member] | FTRs [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 873,000    
Liabilities:      
Risk Management Liabilities 1,382,000    
Level 3 Quantitative Information [Abstract]      
Forward Price Range Low (4.47)    
Forward Price Range High 9.67    
Appalachian Power Co [Member] | Commodity Hedges [Member]
      
Risk Management Assets      
Risk Management Assets 987,000 [10]   302,000 [10]
Liabilities:      
Risk Management Liabilities 450,000 [10]   1,355,000 [10]
Appalachian Power Co [Member] | Commodity Hedges [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10]   0 [10]
Liabilities:      
Risk Management Liabilities 0 [10]   0 [10]
Appalachian Power Co [Member] | Commodity Hedges [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 1,306,000 [10]   498,000 [10]
Liabilities:      
Risk Management Liabilities 769,000 [10]   1,551,000 [10]
Appalachian Power Co [Member] | Commodity Hedges [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10]   0 [10]
Liabilities:      
Risk Management Liabilities 0 [10]   0 [10]
Appalachian Power Co [Member] | Commodity Hedges [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (319,000) [10]   (196,000) [10]
Liabilities:      
Risk Management Liabilities (319,000) [10]   (196,000) [10]
Indiana Michigan Power Co [Member]
      
Risk Management Assets      
Risk Management Assets 34,681,000   50,543,000
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 1,787,529,000   1,705,772,000
Total Assets 1,822,210,000   1,756,315,000
Liabilities:      
Risk Management Liabilities 18,188,000   45,415,000
Changes in the Fair Value of Net Trading Derivatives and other investments      
Beginning Balance 7,541,000 1,263,000  
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) (1,005,000) (2,411,000)  
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date 0 0  
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 0 31,000  
Purchases, Issuances and Settlements 179,000 4,043,000  
Transfers into Level 3 434,000 [5],[6] 1,764,000 [5],[6]  
Transfers out of Level 3 (366,000) [6],[7] (2,814,000) [6],[7]  
Changes in Fair Value Allocated to Regulated Jurisdictions (732,000) [8] 3,738,000 [8]  
Ending Balance 6,051,000 5,614,000  
Indiana Michigan Power Co [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 2,200,000   2,858,000
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 821,031,000   742,090,000
Total Assets 823,231,000   744,948,000
Liabilities:      
Risk Management Liabilities 1,065,000   1,346,000
Indiana Michigan Power Co [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 78,003,000   120,572,000
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 958,074,000   953,407,000
Total Assets 1,036,077,000   1,073,979,000
Liabilities:      
Risk Management Liabilities 70,804,000   131,206,000
Indiana Michigan Power Co [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 9,136,000   11,717,000
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Total Assets 9,136,000   11,717,000
Liabilities:      
Risk Management Liabilities 3,085,000   4,176,000
Indiana Michigan Power Co [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (54,658,000)   (84,604,000)
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 8,424,000   10,275,000
Total Assets (46,234,000)   (74,329,000)
Liabilities:      
Risk Management Liabilities (56,766,000)   (91,313,000)
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member]
      
Risk Management Assets      
Risk Management Assets 34,021,000 [10],[14]   50,343,000 [10],[14]
Liabilities:      
Risk Management Liabilities 17,877,000 [10],[14]   24,960,000 [10],[14]
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 2,200,000 [10],[14]   2,858,000 [10],[14]
Liabilities:      
Risk Management Liabilities 1,065,000 [10],[14]   1,346,000 [10],[14]
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 77,123,000 [10],[14]   120,242,000 [10],[14]
Liabilities:      
Risk Management Liabilities 70,273,000 [10],[14]   110,621,000 [10],[14]
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 9,136,000 [10],[14]   11,717,000 [10],[14]
Liabilities:      
Risk Management Liabilities 3,085,000 [10],[14]   4,176,000 [10],[14]
Indiana Michigan Power Co [Member] | Risk Management Commodity Contracts [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (54,438,000) [10],[14]   (84,474,000) [10],[14]
Liabilities:      
Risk Management Liabilities (56,546,000) [10],[14]   (91,183,000) [10],[14]
Indiana Michigan Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 8,533,000    
Liabilities:      
Risk Management Liabilities 2,130,000    
Level 3 Quantitative Information [Abstract]      
Forward Price Range Low 11.59    
Forward Price Range High 75.95    
Indiana Michigan Power Co [Member] | FTRs [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 603,000    
Liabilities:      
Risk Management Liabilities 955,000    
Level 3 Quantitative Information [Abstract]      
Forward Price Range Low (4.47)    
Forward Price Range High 9.67    
Indiana Michigan Power Co [Member] | Commodity Hedges [Member]
      
Risk Management Assets      
Risk Management Assets 660,000 [10]   200,000 [10]
Liabilities:      
Risk Management Liabilities 311,000 [10]   931,000 [10]
Indiana Michigan Power Co [Member] | Commodity Hedges [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10]   0 [10]
Liabilities:      
Risk Management Liabilities 0 [10]   0 [10]
Indiana Michigan Power Co [Member] | Commodity Hedges [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 880,000 [10]   330,000 [10]
Liabilities:      
Risk Management Liabilities 531,000 [10]   1,061,000 [10]
Indiana Michigan Power Co [Member] | Commodity Hedges [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10]   0 [10]
Liabilities:      
Risk Management Liabilities 0 [10]   0 [10]
Indiana Michigan Power Co [Member] | Commodity Hedges [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (220,000) [10]   (130,000) [10]
Liabilities:      
Risk Management Liabilities (220,000) [10]   (130,000) [10]
Indiana Michigan Power Co [Member] | Interest Rate Foreign Currency Hedges [Member]
      
Liabilities:      
Risk Management Liabilities     19,524,000
Indiana Michigan Power Co [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 1 [Member]
      
Liabilities:      
Risk Management Liabilities     0
Indiana Michigan Power Co [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 2 [Member]
      
Liabilities:      
Risk Management Liabilities     19,524,000
Indiana Michigan Power Co [Member] | Interest Rate Foreign Currency Hedges [Member] | Level 3 [Member]
      
Liabilities:      
Risk Management Liabilities     0
Indiana Michigan Power Co [Member] | Interest Rate Foreign Currency Hedges [Member] | Fair Value Inputs Other [Member]
      
Liabilities:      
Risk Management Liabilities     0
Ohio Power Co [Member]
      
Assets:      
Cash and Cash Equivalents 65,000 [15]   65,000 [15]
Risk Management Assets      
Risk Management Assets 67,437,000   92,601,000
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets 67,502,000   92,666,000
Liabilities:      
Risk Management Liabilities 35,634,000   50,120,000
Changes in the Fair Value of Net Trading Derivatives and other investments      
Beginning Balance 15,429,000 2,666,000  
Realized Gain (Loss) Included in Net Income (or Changes in Net Assets) (2,055,000) (5,056,000)  
Unrealized Gain (Loss) Included in Net Income (or Changes in Net Assets) Relating to Assets Still Held at the Reporting Date (1,988,000) 6,509,000  
Realized and Unrealized Gains (Losses) Included in Other Comprehensive Income 0 66,000  
Purchases, Issuances and Settlements 366,000 8,477,000  
Transfers into Level 3 888,000 [5],[6] 3,699,000 [5],[6]  
Transfers out of Level 3 (749,000) [6],[7] (5,900,000) [6],[7]  
Changes in Fair Value Allocated to Regulated Jurisdictions 490,000 [8] 1,306,000 [8]  
Ending Balance 12,381,000 11,767,000  
Ohio Power Co [Member] | Level 1 [Member]
      
Assets:      
Cash and Cash Equivalents 0 [15]   0 [15]
Risk Management Assets      
Risk Management Assets 4,501,000   5,848,000
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets 4,501,000   5,848,000
Liabilities:      
Risk Management Liabilities 2,178,000   2,753,000
Ohio Power Co [Member] | Level 2 [Member]
      
Assets:      
Cash and Cash Equivalents 26,000 [15]   26,000 [15]
Risk Management Assets      
Risk Management Assets 159,388,000   238,942,000
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets 159,414,000   238,968,000
Liabilities:      
Risk Management Liabilities 146,603,000   228,711,000
Ohio Power Co [Member] | Level 3 [Member]
      
Assets:      
Cash and Cash Equivalents 0 [15]   0 [15]
Risk Management Assets      
Risk Management Assets 18,693,000   23,973,000
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets 18,693,000   23,973,000
Liabilities:      
Risk Management Liabilities 6,312,000   8,544,000
Ohio Power Co [Member] | Fair Value Inputs Other [Member]
      
Assets:      
Cash and Cash Equivalents 39,000 [15]   39,000 [15]
Risk Management Assets      
Risk Management Assets (115,145,000)   (176,162,000)
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets (115,106,000)   (176,123,000)
Liabilities:      
Risk Management Liabilities (119,459,000)   (189,888,000)
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member]
      
Risk Management Assets      
Risk Management Assets 66,065,000 [10],[14]   92,185,000 [10],[14]
Liabilities:      
Risk Management Liabilities 34,998,000 [10],[14]   48,217,000 [10],[14]
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 4,501,000 [10],[14]   5,848,000 [10],[14]
Liabilities:      
Risk Management Liabilities 2,178,000 [10],[14]   2,753,000 [10],[14]
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 157,565,000 [10],[14]   238,254,000 [10],[14]
Liabilities:      
Risk Management Liabilities 145,516,000 [10],[14]   226,536,000 [10],[14]
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 18,693,000 [10],[14]   23,973,000 [10],[14]
Liabilities:      
Risk Management Liabilities 6,312,000 [10],[14]   8,544,000 [10],[14]
Ohio Power Co [Member] | Risk Management Commodity Contracts [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (114,694,000) [10],[14]   (175,890,000) [10],[14]
Liabilities:      
Risk Management Liabilities (119,008,000) [10],[14]   (189,616,000) [10],[14]
Ohio Power Co [Member] | Energy Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 17,459,000    
Liabilities:      
Risk Management Liabilities 4,359,000    
Level 3 Quantitative Information [Abstract]      
Forward Price Range Low 11.59    
Forward Price Range High 75.95    
Ohio Power Co [Member] | FTRs [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 1,234,000    
Liabilities:      
Risk Management Liabilities 1,953,000    
Level 3 Quantitative Information [Abstract]      
Forward Price Range Low (4.47)    
Forward Price Range High 9.67    
Ohio Power Co [Member] | Commodity Hedges [Member]
      
Risk Management Assets      
Risk Management Assets 1,372,000 [10]   416,000 [10]
Liabilities:      
Risk Management Liabilities 636,000 [10]   1,903,000 [10]
Ohio Power Co [Member] | Commodity Hedges [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10]   0 [10]
Liabilities:      
Risk Management Liabilities 0 [10]   0 [10]
Ohio Power Co [Member] | Commodity Hedges [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 1,823,000 [10]   688,000 [10]
Liabilities:      
Risk Management Liabilities 1,087,000 [10]   2,175,000 [10]
Ohio Power Co [Member] | Commodity Hedges [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10]   0 [10]
Liabilities:      
Risk Management Liabilities 0 [10]   0 [10]
Ohio Power Co [Member] | Commodity Hedges [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (451,000) [10]   (272,000) [10]
Liabilities:      
Risk Management Liabilities (451,000) [10]   (272,000) [10]
Public Service Co Of Oklahoma [Member]
      
Risk Management Assets      
Risk Management Assets 716,000   540,000
Liabilities:      
Risk Management Liabilities 3,006,000   5,879,000
Public Service Co Of Oklahoma [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0   0
Liabilities:      
Risk Management Liabilities 0   0
Public Service Co Of Oklahoma [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 1,783,000   1,699,000
Liabilities:      
Risk Management Liabilities 4,075,000   7,038,000
Public Service Co Of Oklahoma [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0   0
Liabilities:      
Risk Management Liabilities 0   0
Public Service Co Of Oklahoma [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (1,067,000)   (1,159,000)
Liabilities:      
Risk Management Liabilities (1,069,000)   (1,159,000)
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member]
      
Risk Management Assets      
Risk Management Assets 655,000 [10],[14]   515,000 [10],[14]
Liabilities:      
Risk Management Liabilities 3,005,000 [10],[14]   5,879,000 [10],[14]
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10],[14]   0 [10],[14]
Liabilities:      
Risk Management Liabilities 0 [10],[14]   0 [10],[14]
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 1,722,000 [10],[14]   1,657,000 [10],[14]
Liabilities:      
Risk Management Liabilities 4,074,000 [10],[14]   7,021,000 [10],[14]
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10],[14]   0 [10],[14]
Liabilities:      
Risk Management Liabilities 0 [10],[14]   0 [10],[14]
Public Service Co Of Oklahoma [Member] | Risk Management Commodity Contracts [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (1,067,000) [10],[14]   (1,142,000) [10],[14]
Liabilities:      
Risk Management Liabilities (1,069,000) [10],[14]   (1,142,000) [10],[14]
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member]
      
Risk Management Assets      
Risk Management Assets 61,000   25,000 [10]
Liabilities:      
Risk Management Liabilities 1,000   0 [10]
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0   0 [10]
Liabilities:      
Risk Management Liabilities 0   0 [10]
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 61,000   42,000 [10]
Liabilities:      
Risk Management Liabilities 1,000   17,000 [10]
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0   0 [10]
Liabilities:      
Risk Management Liabilities 0   0 [10]
Public Service Co Of Oklahoma [Member] | Commodity Hedges [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets 0   (17,000) [10]
Liabilities:      
Risk Management Liabilities 0   (17,000) [10]
Southwestern Electric Power Co [Member]
      
Assets:      
Cash and Cash Equivalents 7,143,000 [15]    
Risk Management Assets      
Risk Management Assets 731,000   695,000
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets 7,874,000    
Liabilities:      
Risk Management Liabilities 824,000   1,128,000
Southwestern Electric Power Co [Member] | Level 1 [Member]
      
Assets:      
Cash and Cash Equivalents 6,160,000 [15]    
Risk Management Assets      
Risk Management Assets 0   0
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets 6,160,000    
Liabilities:      
Risk Management Liabilities 0   0
Southwestern Electric Power Co [Member] | Level 2 [Member]
      
Assets:      
Cash and Cash Equivalents 0 [15]    
Risk Management Assets      
Risk Management Assets 2,836,000   2,845,000
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets 2,836,000    
Liabilities:      
Risk Management Liabilities 2,931,000   3,278,000
Southwestern Electric Power Co [Member] | Level 3 [Member]
      
Assets:      
Cash and Cash Equivalents 0 [15]    
Risk Management Assets      
Risk Management Assets 0   0
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets 0    
Liabilities:      
Risk Management Liabilities 0   0
Southwestern Electric Power Co [Member] | Fair Value Inputs Other [Member]
      
Assets:      
Cash and Cash Equivalents 983,000 [15]    
Risk Management Assets      
Risk Management Assets (2,105,000)   (2,150,000)
Spent Nuclear Fuel and Decommissioning Trusts      
Total Assets (1,122,000)    
Liabilities:      
Risk Management Liabilities (2,107,000)   (2,150,000)
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member]
      
Risk Management Assets      
Risk Management Assets 658,000 [10],[14]   671,000 [10],[14]
Liabilities:      
Risk Management Liabilities 822,000 [10],[14]   1,128,000 [10],[14]
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10],[14]   0 [10],[14]
Liabilities:      
Risk Management Liabilities 0 [10],[14]   0 [10],[14]
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 2,764,000 [10],[14]   2,804,000 [10],[14]
Liabilities:      
Risk Management Liabilities 2,930,000 [10],[14]   3,261,000 [10],[14]
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10],[14]   0 [10],[14]
Liabilities:      
Risk Management Liabilities 0 [10],[14]   0 [10],[14]
Southwestern Electric Power Co [Member] | Risk Management Commodity Contracts [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets (2,106,000) [10],[14]   (2,133,000) [10],[14]
Liabilities:      
Risk Management Liabilities (2,108,000) [10],[14]   (2,133,000) [10],[14]
Southwestern Electric Power Co [Member] | Commodity Hedges [Member]
      
Risk Management Assets      
Risk Management Assets 73,000 [10]   24,000 [10]
Liabilities:      
Risk Management Liabilities 2,000 [10]   0 [10]
Southwestern Electric Power Co [Member] | Commodity Hedges [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10]   0 [10]
Liabilities:      
Risk Management Liabilities 0 [10]   0 [10]
Southwestern Electric Power Co [Member] | Commodity Hedges [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 72,000 [10]   41,000 [10]
Liabilities:      
Risk Management Liabilities 1,000 [10]   17,000 [10]
Southwestern Electric Power Co [Member] | Commodity Hedges [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [10]   0 [10]
Liabilities:      
Risk Management Liabilities 0 [10]   0 [10]
Southwestern Electric Power Co [Member] | Commodity Hedges [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets 1,000 [10]   (17,000) [10]
Liabilities:      
Risk Management Liabilities 1,000 [10]   (17,000) [10]
Cash [Member]
      
Assets:      
Other Temporary Investments 167,000,000 [1]   241,000,000 [1]
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 14,000,000 [16]   17,000,000 [16]
Cash [Member] | Level 1 [Member]
      
Assets:      
Other Temporary Investments 151,000,000 [1]   227,000,000 [1]
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 5,000,000 [16]   7,000,000 [16]
Cash [Member] | Level 2 [Member]
      
Assets:      
Other Temporary Investments 6,000,000 [1]   5,000,000 [1]
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [16]   0 [16]
Cash [Member] | Level 3 [Member]
      
Assets:      
Other Temporary Investments 0 [1]   0 [1]
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [16]   0 [16]
Cash [Member] | Fair Value Inputs Other [Member]
      
Assets:      
Other Temporary Investments 10,000,000 [1]   9,000,000 [1]
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 9,000,000 [16]   10,000,000 [16]
Cash [Member] | Indiana Michigan Power Co [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 13,320,000 [17]   16,783,000 [17]
Cash [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 4,896,000 [17]   6,508,000 [17]
Cash [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [17]   0 [17]
Cash [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [17]   0 [17]
Cash [Member] | Indiana Michigan Power Co [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 8,424,000 [17]   10,275,000 [17]
Fixed Income Funds [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 958,000,000   953,000,000
Fixed Income Funds [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Fixed Income Funds [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 958,000,000   953,000,000
Fixed Income Funds [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Fixed Income Funds [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 958,074,000   953,407,000
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 958,074,000   953,407,000
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Mutual Funds Fixed Income [Member]
      
Assets:      
Other Temporary Investments 76,000,000   67,000,000
Mutual Funds Fixed Income [Member] | Level 1 [Member]
      
Assets:      
Other Temporary Investments 76,000,000   67,000,000
Mutual Funds Fixed Income [Member] | Level 2 [Member]
      
Assets:      
Other Temporary Investments 0   0
Mutual Funds Fixed Income [Member] | Level 3 [Member]
      
Assets:      
Other Temporary Investments 0   0
Mutual Funds Fixed Income [Member] | Fair Value Inputs Other [Member]
      
Assets:      
Other Temporary Investments 0   0
Domestic [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 816,000,000 [18]   736,000,000 [18]
Domestic [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 816,000,000 [18]   736,000,000 [18]
Domestic [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [18]   0 [18]
Domestic [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [18]   0 [18]
Domestic [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [18]   0 [18]
Domestic [Member] | Indiana Michigan Power Co [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 816,135,000 [18]   735,582,000 [18]
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 816,135,000 [18]   735,582,000 [18]
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [18]   0 [18]
Domestic [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [18]   0 [18]
Domestic [Member] | Indiana Michigan Power Co [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0 [18]   0 [18]
Mutual Funds Equity [Member]
      
Assets:      
Other Temporary Investments 18,000,000 [18]   16,000,000 [18]
Mutual Funds Equity [Member] | Level 1 [Member]
      
Assets:      
Other Temporary Investments 18,000,000 [18]   16,000,000 [18]
Mutual Funds Equity [Member] | Level 2 [Member]
      
Assets:      
Other Temporary Investments 0 [18]   0 [18]
Mutual Funds Equity [Member] | Level 3 [Member]
      
Assets:      
Other Temporary Investments 0 [18]   0 [18]
Mutual Funds Equity [Member] | Fair Value Inputs Other [Member]
      
Assets:      
Other Temporary Investments 0 [18]   0 [18]
Cash and Cash Equivalents [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 14,000,000   17,000,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 13,320,000   16,783,000
US Government Agencies Debt Securities [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 642,000,000   648,000,000
US Government Agencies Debt Securities [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
US Government Agencies Debt Securities [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 642,000,000   648,000,000
US Government Agencies Debt Securities [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
US Government Agencies Debt Securities [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 641,780,000   647,918,000
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 641,780,000   647,918,000
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Corporate Debt [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 37,000,000   35,000,000
Corporate Debt [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Corporate Debt [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 37,000,000   35,000,000
Corporate Debt [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Corporate Debt [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Corporate Debt [Member] | Indiana Michigan Power Co [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 37,267,000   35,399,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 37,267,000   35,399,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Corporate Debt [Member] | Indiana Michigan Power Co [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
State and Local Jurisdiction [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 279,000,000   270,000,000
State and Local Jurisdiction [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
State and Local Jurisdiction [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 279,000,000   270,000,000
State and Local Jurisdiction [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
State and Local Jurisdiction [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 279,027,000   270,090,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 1 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 2 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 279,027,000   270,090,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Level 3 [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member] | Fair Value Inputs Other [Member]
      
Spent Nuclear Fuel and Decommissioning Trusts      
Spent Nuclear Fuel and Decommissioning Trusts 0   0
Dedesignated Risk Management Contracts [Member]
      
Risk Management Assets      
Risk Management Assets 11,000,000 [19]   14,000,000 [19]
Dedesignated Risk Management Contracts [Member] | Level 1 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [19]   0 [19]
Dedesignated Risk Management Contracts [Member] | Level 2 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [19]   0 [19]
Dedesignated Risk Management Contracts [Member] | Level 3 [Member]
      
Risk Management Assets      
Risk Management Assets 0 [19]   0 [19]
Dedesignated Risk Management Contracts [Member] | Fair Value Inputs Other [Member]
      
Risk Management Assets      
Risk Management Assets $ 11,000,000 [19]   $ 14,000,000 [19]
[1] Amounts in ''Other'' column primarily represent cash deposits in bank accounts with financial institutions or with third parties. Level 1 and Level 2 amounts primarily represent investments in money market funds.
[2] Included in revenues on the condensed statements of income.
[3] Represents the change in fair value between the beginning of the reporting period and the settlement of the risk management commodity contract.
[4] Represents the settlement of risk management commodity contracts for the reporting period.
[5] Represents existing assets or liabilities that were previously categorized as Level 2.
[6] Transfers are recognized based on their value at the beginning of the reporting period that the transfer occurred.
[7] Represents existing assets or liabilities that were previously categorized as Level 3.
[8] Relates to the net gains (losses) of those contracts that are not reflected on the condensed statements of income. These net gains (losses) are recorded as regulatory liabilities/assets
[9] Represents average price of credit default swaps used to calculate counterparty credit risk, reported in basis points.
[10] Amounts in ''Other'' column primarily represent counterparty netting of risk management and hedging contracts and associated cash collateral under the accounting guidance for ''Derivatives and Hedging.''
[11] The March 31, 2013 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 1 matures $6 million in 2013, ($4) million in periods 2014-2016 and ($3) million in periods 2017-2018; Level 2 matures $17 million in 2013, $73 million in periods 2014-2016, $14 million in periods 2017-2018 and $6 million in periods 2019-2030; Level 3 matures $6 million in 2013, $27 million in periods 2014-2016, $18 million in periods 2017-2018 and $24 million in periods 2019-2030. Risk management commodity contracts are substantially comprised of power contracts.
[12] The December 31, 2012 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 1 matures $9 million in 2013, ($3) million in periods 2014-2016 and ($4) million in periods 2017-2018; Level 2 matures $16 million in 2013, $61 million in periods 2014-2016, $16 million in periods 2017-2018 and $7 million in periods 2019-2030; Level 3 matures $18 million in 2013, $31 million in periods 2014-2016, $13 million in periods 2017-2018 and $24 million in periods 2019-2030. Risk management commodity contracts are substantially comprised of power contracts.
[13] Represents market prices in dollars per MWh
[14] Substantially comprised of power contracts for APCo, I&M and OPCo and coal contracts for PSO and SWEPCo.
[15] Amounts in “Other” column primarily represent cash deposits with third parties. Level 1 and Level 2 amounts primarily represent investments in money market funds.
[16] Amounts in ''Other'' column primarily represent accrued interest receivables from financial institutions.
[17] Amounts in “Other” column primarily represent accrued interest receivables from financial institutions. Level 2 amounts primarily represent investments in money market funds.
[18] Amounts represent publicly traded equity securities and equity-based mutual funds.
[19] Represents contracts that were originally MTM but were subsequently elected as normal under the accounting guidance for ''Derivatives and Hedging.'' At the time of the normal election, the MTM value was frozen and no longer fair valued. This MTM value will be amortized into revenues over the remaining life of the contracts.