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Benefit Plans 3 (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions $ 66,000 $ 64,000 $ 61,000
Benefit Plans Textuals [Abstract]      
Cost of Company Matching Contributions 66,000 64,000 61,000
Matching Contributions Provided Percentage 100.00%    
Second Matching Contributions Provided Percentage 70.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Appalachian Power Co [Member]
      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions 7,579 7,432 7,284
Benefit Plans Textuals [Abstract]      
Cost of Company Matching Contributions 7,579 7,432 7,284
Matching Contributions Provided Percentage 100.00%    
Second Matching Contributions Provided Percentage 70.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Indiana Michigan Power Co [Member]
      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions 9,706 9,541 8,969
Benefit Plans Textuals [Abstract]      
Cost of Company Matching Contributions 9,706 9,541 8,969
Matching Contributions Provided Percentage 100.00%    
Second Matching Contributions Provided Percentage 70.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Ohio Power Co [Member]
      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions 10,798 10,166 9,706
Benefit Plans Textuals [Abstract]      
Cost of Company Matching Contributions 10,798 10,166 9,706
Matching Contributions Provided Percentage 100.00%    
Second Matching Contributions Provided Percentage 70.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Public Service Co of Oklahoma [Member]
      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions 3,732 3,626 3,505
Benefit Plans Textuals [Abstract]      
Cost of Company Matching Contributions 3,732 3,626 3,505
Matching Contributions Provided Percentage 100.00%    
Second Matching Contributions Provided Percentage 70.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Southwestern Electric Power Co [Member]
      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions 4,890 4,438 3,866
Benefit Plans Textuals [Abstract]      
Cost of Company Matching Contributions 4,890 4,438 3,866
Matching Contributions Provided Percentage 100.00%    
Second Matching Contributions Provided Percentage 70.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Pension Plans [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 5,083,000 4,897,000  
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 5,205,000 4,991,000 4,807,000
Accumulated Benefit Obligation 5,083,000 4,897,000  
Fair Value of Plan Assets 4,696,000 4,303,000 3,858,000
Underfunded Status, Accumulated Benefit Obligation (387,000) (594,000)  
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 108,000    
Components of Net Periodic Benefit Cost      
Service Cost 76,000 72,000 111,000
Interest Cost 223,000 237,000 253,000
Expected Return on Plan Assets (319,000) (314,000) (312,000)
Curtailment 0 0 0
Amortization of Transition Obligation 0 0 0
Amortization of Prior Service Cost (Credit) (1,000) 1,000 0
Amortization of Net Actuarial Loss 155,000 122,000 89,000
Net Periodic Benefit Cost 134,000 118,000 141,000
Capitalized Portion (42,000) (37,000) (44,000)
Net Periodic Benefit Cost Recognized as Expense 92,000 81,000 97,000
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 176,000    
Prior Service Cost (Credit) 3,000    
Total Estimated 2013 Amortization 179,000    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 179,000    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 108,000    
Pension Plans [Member] | Appalachian Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 708,667 673,201  
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 718,460 681,450 652,219
Accumulated Benefit Obligation 708,667 673,201  
Fair Value of Plan Assets 621,570 570,756 512,836
Underfunded Status, Accumulated Benefit Obligation (87,097) (102,445)  
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 11,883    
Components of Net Periodic Benefit Cost      
Service Cost 7,565 7,199 12,908
Interest Cost 30,211 32,293 33,956
Expected Return on Plan Assets (41,944) (41,833) (43,805)
Amortization of Transition Obligation 0 0 0
Amortization of Prior Service Cost (Credit) 475 917 917
Amortization of Net Actuarial Loss 20,339 16,570 11,842
Net Periodic Benefit Cost 16,646 15,146 15,818
Capitalized Portion (6,525) (5,604) (6,058)
Net Periodic Benefit Cost Recognized as Expense 10,121 9,542 9,760
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 24,305    
Prior Service Cost (Credit) 198    
Total Estimated 2013 Amortization 24,503    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 24,503    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 11,883    
Pension Plans [Member] | Indiana Michigan Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 603,648 570,023  
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 618,973 581,677 560,982
Accumulated Benefit Obligation 603,648 570,023  
Fair Value of Plan Assets 552,026 503,926 451,688
Underfunded Status, Accumulated Benefit Obligation (51,622) (66,097)  
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 14,867    
Components of Net Periodic Benefit Cost      
Service Cost 9,908 9,447 15,284
Interest Cost 26,245 27,726 29,085
Expected Return on Plan Assets (37,566) (36,856) (35,040)
Amortization of Transition Obligation 0 0 0
Amortization of Prior Service Cost (Credit) 407 744 744
Amortization of Net Actuarial Loss 17,569 14,144 10,065
Net Periodic Benefit Cost 16,563 15,205 20,138
Capitalized Portion (3,114) (3,163) (4,028)
Net Periodic Benefit Cost Recognized as Expense 13,449 12,042 16,110
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 20,939    
Prior Service Cost (Credit) 195    
Total Estimated 2013 Amortization 21,134    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 21,134    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 14,867    
Pension Plans [Member] | Ohio Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 1,049,592 1,006,429  
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 1,068,186 1,020,890 984,089
Accumulated Benefit Obligation 1,049,592 1,006,429  
Fair Value of Plan Assets 1,015,115 925,939 799,281
Underfunded Status, Accumulated Benefit Obligation (34,477) (80,490)  
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 8,965    
Components of Net Periodic Benefit Cost      
Service Cost 11,003 10,230 17,254
Interest Cost 45,194 48,350 51,900
Expected Return on Plan Assets (68,401) (65,464) (69,077)
Curtailment 0 0 0
Amortization of Transition Obligation 0 0 0
Amortization of Prior Service Cost (Credit) 743 1,474 1,474
Amortization of Net Actuarial Loss 30,439 24,828 18,150
Net Periodic Benefit Cost 18,978 19,418 19,701
Capitalized Portion (7,060) (6,932) (6,843)
Net Periodic Benefit Cost Recognized as Expense 11,918 12,486 12,858
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 36,137    
Prior Service Cost (Credit) 283    
Total Estimated 2013 Amortization 36,420    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 36,420    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 8,965    
Pension Plans [Member] | Public Service Co of Oklahoma [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 271,025 270,598  
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 279,685 277,448 268,180
Accumulated Benefit Obligation 271,025 270,598  
Fair Value of Plan Assets 264,823 245,769 213,576
Underfunded Status, Accumulated Benefit Obligation (6,202) (24,829)  
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 6,089    
Components of Net Periodic Benefit Cost      
Service Cost 5,951 5,760 6,052
Interest Cost 12,301 13,285 14,888
Expected Return on Plan Assets (18,015) (17,464) (19,739)
Amortization of Transition Obligation 0 0 0
Amortization of Prior Service Cost (Credit) (948) (950) (950)
Amortization of Net Actuarial Loss 8,206 6,757 5,188
Net Periodic Benefit Cost 7,495 7,388 5,439
Capitalized Portion (2,533) (2,379) (1,806)
Net Periodic Benefit Cost Recognized as Expense 4,962 5,009 3,633
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 9,464    
Prior Service Cost (Credit) 297    
Total Estimated 2013 Amortization 9,761    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 9,761    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 6,089    
Pension Plans [Member] | Southwestern Electric Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 274,958 271,032  
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 285,560 277,594 267,206
Accumulated Benefit Obligation 274,958 271,032  
Fair Value of Plan Assets 279,699 255,861 224,618
Underfunded Status, Accumulated Benefit Obligation   (15,171)  
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 11,345    
Components of Net Periodic Benefit Cost      
Service Cost 7,099 6,573 7,046
Interest Cost 12,537 13,331 15,093
Expected Return on Plan Assets (18,866) (18,380) (19,489)
Amortization of Transition Obligation 0 0 0
Amortization of Prior Service Cost (Credit) (793) (795) (796)
Amortization of Net Actuarial Loss 8,330 6,759 5,242
Net Periodic Benefit Cost 8,307 7,488 7,096
Capitalized Portion (2,924) (2,636) (2,406)
Net Periodic Benefit Cost Recognized as Expense 5,383 4,852 4,690
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 9,662    
Prior Service Cost (Credit) 350    
Total Estimated 2013 Amortization 10,012    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 10,012    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 11,345    
Pension Plans [Member] | Pension Payments [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 340,000    
2014 349,000    
2015 356,000    
2016 359,000    
2017 364,000    
Years 2018 to 2022, in Total 1,844,000    
Pension Plans [Member] | Pension Payments [Member] | Appalachian Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 45,750    
2014 47,455    
2015 46,625    
2016 47,604    
2017 48,367    
Years 2018 to 2022, in Total 245,312    
Pension Plans [Member] | Pension Payments [Member] | Indiana Michigan Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 36,365    
2014 36,958    
2015 38,694    
2016 39,469    
2017 40,350    
Years 2018 to 2022, in Total 213,444    
Pension Plans [Member] | Pension Payments [Member] | Ohio Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 72,470    
2014 73,771    
2015 73,945    
2016 75,347    
2017 75,575    
Years 2018 to 2022, in Total 370,934    
Pension Plans [Member] | Pension Payments [Member] | Public Service Co of Oklahoma [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 20,560    
2014 21,772    
2015 22,310    
2016 22,297    
2017 22,347    
Years 2018 to 2022, in Total 110,866    
Pension Plans [Member] | Pension Payments [Member] | Southwestern Electric Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 21,004    
2014 22,223    
2015 22,352    
2016 22,278    
2017 23,162    
Years 2018 to 2022, in Total 114,257    
Other Postretirement Benefit Plans [Member]
      
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 1,849,000 2,227,000 2,125,000
Fair Value of Plan Assets 1,568,000 1,410,000 1,461,000
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 4,000    
Components of Net Periodic Benefit Cost      
Service Cost 47,000 42,000 47,000
Interest Cost 103,000 109,000 113,000
Expected Return on Plan Assets (101,000) (109,000) (105,000)
Curtailment 0 1,000 0
Amortization of Transition Obligation 1,000 2,000 27,000
Amortization of Prior Service Cost (Credit) (18,000) (1,000) 0
Amortization of Net Actuarial Loss 57,000 29,000 29,000
Net Periodic Benefit Cost 89,000 73,000 111,000
Capitalized Portion (28,000) (22,000) (35,000)
Net Periodic Benefit Cost Recognized as Expense 61,000 51,000 76,000
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 64,000    
Prior Service Cost (Credit) (69,000)    
Total Estimated 2013 Amortization (5,000)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (5,000)    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 4,000    
Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]
      
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 348,990 395,482 383,152
Fair Value of Plan Assets 267,758 229,735 243,771
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 3,079    
Components of Net Periodic Benefit Cost      
Service Cost 5,387 4,983 5,722
Interest Cost 18,462 19,468 20,300
Expected Return on Plan Assets (16,753) (17,985) (17,628)
Amortization of Transition Obligation 780 1,167 5,244
Amortization of Prior Service Cost (Credit) (2,862) (171) 0
Amortization of Net Actuarial Loss 10,526 5,839 5,410
Net Periodic Benefit Cost 15,540 13,301 19,048
Capitalized Portion (6,092) (4,921) (7,295)
Net Periodic Benefit Cost Recognized as Expense 9,448 8,380 11,753
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 12,114    
Prior Service Cost (Credit) (10,050)    
Total Estimated 2013 Amortization 2,064    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 2,064    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 3,079    
Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]
      
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 218,553 277,353 266,742
Fair Value of Plan Assets 194,128 181,237 188,690
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 315    
Components of Net Periodic Benefit Cost      
Service Cost 6,621 6,119 6,750
Interest Cost 12,785 13,610 14,164
Expected Return on Plan Assets (12,847) (13,886) (13,397)
Amortization of Transition Obligation 132 188 2,814
Amortization of Prior Service Cost (Credit) (2,383) (237) 0
Amortization of Net Actuarial Loss 7,050 3,566 3,526
Net Periodic Benefit Cost 11,358 9,360 13,857
Capitalized Portion (2,135) (1,947) (2,771)
Net Periodic Benefit Cost Recognized as Expense 9,223 7,413 11,086
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 7,624    
Prior Service Cost (Credit) (9,421)    
Total Estimated 2013 Amortization (1,797)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (1,797)    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 315    
Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]
      
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 466,290 519,892 506,255
Fair Value of Plan Assets 366,301 311,836 333,198
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 1,027    
Components of Net Periodic Benefit Cost      
Service Cost 8,748 7,827 8,187
Interest Cost 24,189 25,497 26,498
Expected Return on Plan Assets (22,555) (24,514) (24,092)
Curtailment 0 605 0
Amortization of Transition Obligation 104 150 6,642
Amortization of Prior Service Cost (Credit) (3,873) (212) 0
Amortization of Net Actuarial Loss 13,669 7,298 6,877
Net Periodic Benefit Cost 20,282 16,651 24,112
Capitalized Portion (7,545) (5,944) (8,334)
Net Periodic Benefit Cost Recognized as Expense 12,737 10,707 15,778
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 16,198    
Prior Service Cost (Credit) (12,922)    
Total Estimated 2013 Amortization 3,276    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 3,276    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 1,027    
Other Postretirement Benefit Plans [Member] | Public Service Co of Oklahoma [Member]
      
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 99,680 125,164 116,935
Fair Value of Plan Assets 90,521 83,090 83,917
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 0    
Components of Net Periodic Benefit Cost      
Service Cost 2,836 2,621 2,815
Interest Cost 5,797 6,046 6,360
Expected Return on Plan Assets (5,922) (6,264) (6,110)
Amortization of Transition Obligation 0 0 2,805
Amortization of Prior Service Cost (Credit) (1,079) (75) 0
Amortization of Net Actuarial Loss 3,189 1,553 1,573
Net Periodic Benefit Cost 4,821 3,881 7,443
Capitalized Portion (1,629) (1,249) (2,471)
Net Periodic Benefit Cost Recognized as Expense 3,192 2,632 4,972
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 3,480    
Prior Service Cost (Credit) (4,290)    
Total Estimated 2013 Amortization (810)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (810)    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 0    
Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]
      
Underfunded Accumulated Benefit Obligation      
Projected Benefit Obligation 109,948 145,160 129,726
Fair Value of Plan Assets 99,846 96,364 93,097
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2013 0    
Components of Net Periodic Benefit Cost      
Service Cost 3,324 3,029 3,108
Interest Cost 6,673 6,969 6,940
Expected Return on Plan Assets (6,795) (7,200) (6,646)
Amortization of Transition Obligation 0 0 2,461
Amortization of Prior Service Cost (Credit) (933) 258 0
Amortization of Net Actuarial Loss 3,659 1,785 1,711
Net Periodic Benefit Cost 5,928 4,841 7,574
Capitalized Portion (2,087) (1,704) (2,568)
Net Periodic Benefit Cost Recognized as Expense 3,841 3,137 5,006
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Net Actuarial Loss 3,838    
Prior Service Cost (Credit) (5,155)    
Total Estimated 2013 Amortization (1,317)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (1,317)    
Benefit Plans Textuals [Abstract]      
Expected Contributions and Payments During 2013 0    
Other Postretirement Benefit Plans [Member] | Medicare Subsidy Receipts [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 0    
2014 0    
2015 0    
2016 0    
2017 0    
Years 2018 to 2022, in Total 2,000    
Other Postretirement Benefit Plans [Member] | Medicare Subsidy Receipts [Member] | Appalachian Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 243    
2014 257    
2015 269    
2016 278    
2017 283    
Years 2018 to 2022, in Total 1,452    
Other Postretirement Benefit Plans [Member] | Medicare Subsidy Receipts [Member] | Indiana Michigan Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 25    
2014 24    
2015 23    
2016 23    
2017 22    
Years 2018 to 2022, in Total 97    
Other Postretirement Benefit Plans [Member] | Medicare Subsidy Receipts [Member] | Ohio Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 41    
2014 47    
2015 58    
2016 65    
2017 76    
Years 2018 to 2022, in Total 599    
Other Postretirement Benefit Plans [Member] | Medicare Subsidy Receipts [Member] | Public Service Co of Oklahoma [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 0    
2014 0    
2015 0    
2016 0    
2017 0    
Years 2018 to 2022, in Total 0    
Other Postretirement Benefit Plans [Member] | Medicare Subsidy Receipts [Member] | Southwestern Electric Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 0    
2014 0    
2015 0    
2016 0    
2017 0    
Years 2018 to 2022, in Total 0    
Other Postretirement Benefit Plans [Member] | Benefit Payments [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 140,000    
2014 146,000    
2015 153,000    
2016 162,000    
2017 171,000    
Years 2018 to 2022, in Total 990,000    
Other Postretirement Benefit Plans [Member] | Benefit Payments [Member] | Appalachian Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 26,427    
2014 27,549    
2015 28,553    
2016 29,738    
2017 30,834    
Years 2018 to 2022, in Total 172,977    
Other Postretirement Benefit Plans [Member] | Benefit Payments [Member] | Indiana Michigan Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 17,092    
2014 17,999    
2015 19,150    
2016 20,468    
2017 21,549    
Years 2018 to 2022, in Total 127,047    
Other Postretirement Benefit Plans [Member] | Benefit Payments [Member] | Ohio Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 34,561    
2014 35,532    
2015 36,755    
2016 38,435    
2017 39,543    
Years 2018 to 2022, in Total 224,357    
Other Postretirement Benefit Plans [Member] | Benefit Payments [Member] | Public Service Co of Oklahoma [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 7,821    
2014 8,169    
2015 8,676    
2016 9,239    
2017 9,712    
Years 2018 to 2022, in Total 56,882    
Other Postretirement Benefit Plans [Member] | Benefit Payments [Member] | Southwestern Electric Power Co [Member]
      
Estimated Future Benefit Payments and Contributions      
2013 8,143    
2014 8,748    
2015 9,233    
2016 9,879    
2017 10,582    
Years 2018 to 2022, in Total 64,145    
Qualified Pension Plans [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 5,001,000 4,808,000  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 5,001,000 4,808,000  
Qualified Pension Plans [Member] | Appalachian Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 708,476 672,967  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 708,476 672,967  
Qualified Pension Plans [Member] | Indiana Michigan Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 603,448 569,855  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 603,448 569,855  
Qualified Pension Plans [Member] | Ohio Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 1,048,796 1,005,608  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 1,048,796 1,005,608  
Qualified Pension Plans [Member] | Public Service Co of Oklahoma [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 269,738 269,230  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 269,738 269,230  
Qualified Pension Plans [Member] | Southwestern Electric Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 273,860 269,809  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 273,860 269,809  
Nonqualified Pension Plans [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 82,000 89,000  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 82,000 89,000  
Nonqualified Pension Plans [Member] | Appalachian Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 191 234  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 191 234  
Nonqualified Pension Plans [Member] | Indiana Michigan Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 200 168  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 200 168  
Nonqualified Pension Plans [Member] | Ohio Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 796 821  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 796 821  
Nonqualified Pension Plans [Member] | Public Service Co of Oklahoma [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 1,287 1,368  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 1,287 1,368  
Nonqualified Pension Plans [Member] | Southwestern Electric Power Co [Member]
      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 1,098 1,223  
Underfunded Accumulated Benefit Obligation      
Accumulated Benefit Obligation 1,098 1,223  
Fair Value of Plan Assets 0    
Underfunded Status, Accumulated Benefit Obligation (1,098)    
Net of Tax AOCI [Member] | Pension Plans [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 20,000    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 20,000    
Net of Tax AOCI [Member] | Pension Plans [Member] | Appalachian Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 88    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 88    
Net of Tax AOCI [Member] | Pension Plans [Member] | Indiana Michigan Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 833    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 833    
Net of Tax AOCI [Member] | Pension Plans [Member] | Ohio Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 11,071    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 11,071    
Net of Tax AOCI [Member] | Pension Plans [Member] | Public Service Co of Oklahoma [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 0    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 0    
Net of Tax AOCI [Member] | Pension Plans [Member] | Southwestern Electric Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 0    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 0    
Net of Tax AOCI [Member] | Other Postretirement Benefit Plans [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 1,000    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 1,000    
Net of Tax AOCI [Member] | Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 1,277    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 1,277    
Net of Tax AOCI [Member] | Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization (20)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (20)    
Net of Tax AOCI [Member] | Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 1,740    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 1,740    
Net of Tax AOCI [Member] | Other Postretirement Benefit Plans [Member] | Public Service Co of Oklahoma [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 0    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 0    
Net of Tax AOCI [Member] | Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization (272)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (272)    
Deferred Income Taxes [Member] | Pension Plans [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 11,000    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 11,000    
Deferred Income Taxes [Member] | Pension Plans [Member] | Appalachian Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 48    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 48    
Deferred Income Taxes [Member] | Pension Plans [Member] | Indiana Michigan Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 449    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 449    
Deferred Income Taxes [Member] | Pension Plans [Member] | Ohio Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 5,962    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 5,962    
Deferred Income Taxes [Member] | Pension Plans [Member] | Public Service Co of Oklahoma [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 0    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 0    
Deferred Income Taxes [Member] | Pension Plans [Member] | Southwestern Electric Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 0    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 0    
Deferred Income Taxes [Member] | Other Postretirement Benefit Plans [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 1,000    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 1,000    
Deferred Income Taxes [Member] | Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 688    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 688    
Deferred Income Taxes [Member] | Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization (10)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (10)    
Deferred Income Taxes [Member] | Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 937    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 937    
Deferred Income Taxes [Member] | Other Postretirement Benefit Plans [Member] | Public Service Co of Oklahoma [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 0    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 0    
Deferred Income Taxes [Member] | Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization (146)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (146)    
Regulatory Assets [Member] | Pension Plans [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 148,000    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 148,000    
Regulatory Assets [Member] | Pension Plans [Member] | Appalachian Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 24,367    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 24,367    
Regulatory Assets [Member] | Pension Plans [Member] | Indiana Michigan Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 19,852    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 19,852    
Regulatory Assets [Member] | Pension Plans [Member] | Ohio Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 19,387    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 19,387    
Regulatory Assets [Member] | Pension Plans [Member] | Public Service Co of Oklahoma [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 9,761    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 9,761    
Regulatory Assets [Member] | Pension Plans [Member] | Southwestern Electric Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 10,012    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 10,012    
Regulatory Assets [Member] | Other Postretirement Benefit Plans [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization (7,000)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (7,000)    
Regulatory Assets [Member] | Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 99    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 99    
Regulatory Assets [Member] | Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization (1,767)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (1,767)    
Regulatory Assets [Member] | Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization 599    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 599    
Regulatory Assets [Member] | Other Postretirement Benefit Plans [Member] | Public Service Co of Oklahoma [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization (810)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 (810)    
Regulatory Assets [Member] | Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]
      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013      
Total Estimated 2013 Amortization (899)    
Expected to be Recorded as      
Estimated Amounts Expected to be Amortized to Net Periodic Benefit Costs in 2013 $ (899)