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Benefit Plans 3 (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions $ 87,900 $ 81,900 $ 79,900
Benefit Plans Textuals [Abstract]      
Matching Contributions Provided Percentage 100.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Matching Contributions Provided Percentage 70.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Multiemployer Plans Withdrawal Obligation $ 13,000 12,000  
Noncurrent Regulatory Assets 5,092,400 4,762,000  
Noncurrent Regulatory Liabilities 8,182,400 8,115,600  
Multiemployer Plan, Employer Contribution, Cost 396 329 339
AEP Texas Inc. [Member]      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions $ 7,100 6,500 6,400
Benefit Plans Textuals [Abstract]      
Matching Contributions Provided Percentage 100.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Matching Contributions Provided Percentage 70.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Noncurrent Regulatory Assets $ 315,300 298,300  
Noncurrent Regulatory Liabilities 1,261,400 1,259,600  
Appalachian Power Co [Member]      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions $ 8,400 7,800 7,600
Benefit Plans Textuals [Abstract]      
Matching Contributions Provided Percentage 100.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Matching Contributions Provided Percentage 70.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Noncurrent Regulatory Assets $ 1,155,100 1,058,600  
Noncurrent Regulatory Liabilities 1,081,900 1,143,600  
Indiana Michigan Power Co [Member]      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions $ 11,000 11,100 10,900
Benefit Plans Textuals [Abstract]      
Matching Contributions Provided Percentage 100.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Matching Contributions Provided Percentage 70.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Noncurrent Regulatory Assets $ 406,300 459,600  
Noncurrent Regulatory Liabilities 2,052,300 1,702,200  
Ohio Power Co [Member]      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions $ 8,200 7,700 7,200
Benefit Plans Textuals [Abstract]      
Matching Contributions Provided Percentage 100.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Matching Contributions Provided Percentage 70.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Noncurrent Regulatory Assets $ 455,000 327,300  
Noncurrent Regulatory Liabilities 1,003,600 1,044,000  
Public Service Co Of Oklahoma [Member]      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions $ 5,300 4,700 4,600
Benefit Plans Textuals [Abstract]      
Matching Contributions Provided Percentage 100.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Matching Contributions Provided Percentage 70.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Noncurrent Regulatory Assets $ 522,700 653,700  
Noncurrent Regulatory Liabilities 765,600 809,100  
Southwestern Electric Power Co [Member]      
American Electric Power System Retirement Savings Plans      
Cost of Company Matching Contributions $ 6,700 6,400 6,400
Benefit Plans Textuals [Abstract]      
Matching Contributions Provided Percentage 100.00%    
Eligible Compensation Contribution by Employee Percentage 1.00%    
Second Matching Contributions Provided Percentage 70.00%    
Second Eligible Compensation Contribution by Employee Percentage 5.00%    
Noncurrent Regulatory Assets $ 1,131,800 1,042,400  
Noncurrent Regulatory Liabilities 756,100 825,700  
Pension Plans [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 3,933,500 3,883,000  
Underfunded Benefit Obligation      
Projected Benefit Obligation 4,161,600 4,072,700 5,187,000
Accumulated Benefit Obligation 3,933,500 3,883,000  
Fair Value of Plan Assets 4,118,200 4,124,700 5,352,900
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 6,700    
Components of Net Periodic Benefit Cost      
Service Cost 94,300 123,100 129,200
Interest Cost 219,200 148,200 137,200
Expected Return on Plan Assets (339,200) (253,400) (229,700)
Amortization of Net Actuarial Loss 1,400 63,000 101,500
Net Periodic Benefit Cost (Credit) (24,300) 80,900 138,200
Capitalized Portion (43,600) (53,800) (55,700)
Net Periodic Benefit Cost (Credit) Recognized in Expense (67,900) 27,100 82,500
Pension Plans [Member] | Pension Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 369,500    
Year Two 361,800    
Year Three 365,700    
Year Four 361,900    
Year Five 357,800    
After Year Five for Next Five Years, in Total 1,657,600    
Pension Plans [Member] | AEP Texas Inc. [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 323,200 317,900  
Underfunded Benefit Obligation      
Projected Benefit Obligation 343,100 334,100 419,800
Accumulated Benefit Obligation 323,200 317,900  
Fair Value of Plan Assets 332,700 335,100 444,900
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 300    
Components of Net Periodic Benefit Cost      
Service Cost 8,200 11,100 11,800
Interest Cost 18,300 12,100 11,200
Expected Return on Plan Assets (28,100) (21,000) (19,500)
Amortization of Net Actuarial Loss 100 5,200 8,300
Net Periodic Benefit Cost (Credit) (1,500) 7,400 11,800
Capitalized Portion (4,700) (6,200) (6,600)
Net Periodic Benefit Cost (Credit) Recognized in Expense (6,200) 1,200 5,200
Pension Plans [Member] | AEP Texas Inc. [Member] | Pension Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 36,700    
Year Two 34,300    
Year Three 34,500    
Year Four 32,200    
Year Five 32,200    
After Year Five for Next Five Years, in Total 133,500    
Pension Plans [Member] | Appalachian Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 485,700 470,400  
Underfunded Benefit Obligation      
Projected Benefit Obligation 504,100 485,700 621,700
Accumulated Benefit Obligation 485,700 470,400  
Fair Value of Plan Assets 549,800 531,700 683,300
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 0    
Components of Net Periodic Benefit Cost      
Service Cost 9,100 11,400 11,900
Interest Cost 26,400 17,500 16,400
Expected Return on Plan Assets (44,600) (32,300) (29,100)
Amortization of Net Actuarial Loss 0 7,400 12,000
Net Periodic Benefit Cost (Credit) (9,100) 4,000 11,200
Capitalized Portion (4,200) (5,000) (5,200)
Net Periodic Benefit Cost (Credit) Recognized in Expense (13,300) (1,000) 6,000
Pension Plans [Member] | Appalachian Power Co [Member] | Pension Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 43,900    
Year Two 43,300    
Year Three 44,100    
Year Four 42,600    
Year Five 43,500    
After Year Five for Next Five Years, in Total 200,000    
Pension Plans [Member] | Indiana Michigan Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 451,000 445,000  
Underfunded Benefit Obligation      
Projected Benefit Obligation 477,000 466,800 612,100
Accumulated Benefit Obligation 451,000 445,000  
Fair Value of Plan Assets 550,600 533,700 681,500
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 0    
Components of Net Periodic Benefit Cost      
Service Cost 11,900 16,200 17,500
Interest Cost 24,900 17,000 16,200
Expected Return on Plan Assets (44,200) (32,400) (28,900)
Amortization of Net Actuarial Loss 100 7,100 11,700
Net Periodic Benefit Cost (Credit) (7,300) 7,900 16,500
Capitalized Portion (3,600) (4,600) (4,900)
Net Periodic Benefit Cost (Credit) Recognized in Expense (10,900) 3,300 11,600
Pension Plans [Member] | Indiana Michigan Power Co [Member] | Pension Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 39,000    
Year Two 39,700    
Year Three 39,700    
Year Four 39,800    
Year Five 39,400    
After Year Five for Next Five Years, in Total 189,400    
Pension Plans [Member] | Ohio Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 354,100 344,200  
Underfunded Benefit Obligation      
Projected Benefit Obligation 378,400 363,600 470,700
Accumulated Benefit Obligation 354,100 344,200  
Fair Value of Plan Assets 419,500 406,400 524,800
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 0    
Components of Net Periodic Benefit Cost      
Service Cost 8,400 11,200 11,400
Interest Cost 19,800 13,300 12,500
Expected Return on Plan Assets (34,000) (24,800) (22,300)
Amortization of Net Actuarial Loss 0 5,500 9,100
Net Periodic Benefit Cost (Credit) (5,800) 5,200 10,700
Capitalized Portion (4,700) (6,100) (6,200)
Net Periodic Benefit Cost (Credit) Recognized in Expense (10,500) (900) 4,500
Pension Plans [Member] | Ohio Power Co [Member] | Pension Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 32,600    
Year Two 32,700    
Year Three 32,500    
Year Four 32,400    
Year Five 31,300    
After Year Five for Next Five Years, in Total 144,500    
Pension Plans [Member] | Public Service Co Of Oklahoma [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 187,800 180,300  
Underfunded Benefit Obligation      
Projected Benefit Obligation 202,200 192,300 252,600
Accumulated Benefit Obligation 187,800 180,300  
Fair Value of Plan Assets 222,700 218,500 286,200
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 100    
Components of Net Periodic Benefit Cost      
Service Cost 5,500 7,400 8,000
Interest Cost 10,700 7,000 6,700
Expected Return on Plan Assets (18,300) (13,400) (12,300)
Amortization of Net Actuarial Loss 0 2,900 4,900
Net Periodic Benefit Cost (Credit) (2,100) 3,900 7,300
Capitalized Portion (2,500) (3,200) (3,400)
Net Periodic Benefit Cost (Credit) Recognized in Expense (4,600) 700 3,900
Pension Plans [Member] | Public Service Co Of Oklahoma [Member] | Pension Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 19,700    
Year Two 19,200    
Year Three 19,400    
Year Four 19,300    
Year Five 19,000    
After Year Five for Next Five Years, in Total 81,000    
Pension Plans [Member] | Southwestern Electric Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 242,900 235,100  
Underfunded Benefit Obligation      
Projected Benefit Obligation 261,200 250,700 317,700
Accumulated Benefit Obligation 242,900 235,100  
Fair Value of Plan Assets 227,500 231,300 308,300
Underfunded Status, Projected Benefit Obligation (33,700) (19,400)  
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 100    
Components of Net Periodic Benefit Cost      
Service Cost 7,700 10,600 11,200
Interest Cost 13,900 9,100 8,500
Expected Return on Plan Assets (19,400) (14,600) (13,500)
Amortization of Net Actuarial Loss 100 3,800 6,200
Net Periodic Benefit Cost (Credit) 2,300 8,900 12,400
Capitalized Portion (3,000) (4,000) (4,100)
Net Periodic Benefit Cost (Credit) Recognized in Expense (700) 4,900 8,300
Pension Plans [Member] | Southwestern Electric Power Co [Member] | Pension Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 24,400    
Year Two 25,800    
Year Three 26,100    
Year Four 25,300    
Year Five 23,700    
After Year Five for Next Five Years, in Total 105,600    
Qualified Pension Plans [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 3,878,700 3,827,400  
Underfunded Benefit Obligation      
Accumulated Benefit Obligation 3,878,700 3,827,400  
Qualified Pension Plans [Member] | AEP Texas Inc. [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 321,100 315,400  
Underfunded Benefit Obligation      
Accumulated Benefit Obligation 321,100 315,400  
Qualified Pension Plans [Member] | Appalachian Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 485,600 470,100  
Underfunded Benefit Obligation      
Accumulated Benefit Obligation 485,600 470,100  
Qualified Pension Plans [Member] | Indiana Michigan Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 450,300 443,800  
Underfunded Benefit Obligation      
Accumulated Benefit Obligation 450,300 443,800  
Qualified Pension Plans [Member] | Ohio Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 354,000 344,100  
Underfunded Benefit Obligation      
Accumulated Benefit Obligation 354,000 344,100  
Qualified Pension Plans [Member] | Public Service Co Of Oklahoma [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 186,600 179,100  
Underfunded Benefit Obligation      
Accumulated Benefit Obligation 186,600 179,100  
Qualified Pension Plans [Member] | Southwestern Electric Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 241,900 234,000  
Underfunded Benefit Obligation      
Accumulated Benefit Obligation 241,900 234,000  
Nonqualified Pension Plans [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 54,800 55,600  
Underfunded Benefit Obligation      
Projected Benefit Obligation 60,700 61,500  
Accumulated Benefit Obligation 54,800 55,600  
Fair Value of Plan Assets 0 0  
Underfunded Status, Projected Benefit Obligation (60,700) (61,500)  
Underfunded Status, Accumulated Benefit Obligation (54,800) (55,600)  
Nonqualified Pension Plans [Member] | AEP Texas Inc. [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 2,100 2,500  
Underfunded Benefit Obligation      
Projected Benefit Obligation   2,700  
Accumulated Benefit Obligation 2,100 2,500  
Fair Value of Plan Assets 0 0  
Underfunded Status, Projected Benefit Obligation (10,400) (2,700)  
Underfunded Status, Accumulated Benefit Obligation (2,100) (2,500)  
Nonqualified Pension Plans [Member] | Appalachian Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 100 300  
Underfunded Benefit Obligation      
Projected Benefit Obligation 400 600  
Accumulated Benefit Obligation 100 300  
Fair Value of Plan Assets 0 0  
Underfunded Status, Projected Benefit Obligation (400) (600)  
Underfunded Status, Accumulated Benefit Obligation (100) (300)  
Nonqualified Pension Plans [Member] | Indiana Michigan Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 700 1,200  
Underfunded Benefit Obligation      
Projected Benefit Obligation 1,200 1,600  
Accumulated Benefit Obligation 700 1,200  
Fair Value of Plan Assets 0 0  
Underfunded Status, Projected Benefit Obligation (1,200) (1,600)  
Underfunded Status, Accumulated Benefit Obligation (700) (1,200)  
Nonqualified Pension Plans [Member] | Ohio Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 100 100  
Underfunded Benefit Obligation      
Projected Benefit Obligation 300 300  
Accumulated Benefit Obligation 100 100  
Fair Value of Plan Assets 0 0  
Underfunded Status, Projected Benefit Obligation (300) (300)  
Underfunded Status, Accumulated Benefit Obligation (100) (100)  
Nonqualified Pension Plans [Member] | Public Service Co Of Oklahoma [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 1,200 1,200  
Underfunded Benefit Obligation      
Projected Benefit Obligation 1,400 1,500  
Accumulated Benefit Obligation 1,200 1,200  
Fair Value of Plan Assets 0 0  
Underfunded Status, Projected Benefit Obligation (1,400) (1,500)  
Underfunded Status, Accumulated Benefit Obligation (1,200) (1,200)  
Nonqualified Pension Plans [Member] | Southwestern Electric Power Co [Member]      
Accumulated Benefit Obligation      
Accumulated Benefit Obligation 1,000 1,100  
Underfunded Benefit Obligation      
Accumulated Benefit Obligation 1,000 1,100  
Fair Value of Plan Assets 227,500 231,300  
Underfunded Status, Accumulated Benefit Obligation (15,400) (3,800)  
Other Postretirement Benefit Plans [Member]      
Underfunded Benefit Obligation      
Projected Benefit Obligation 849,500 872,600 1,041,300
Fair Value of Plan Assets 1,673,300 1,549,300 2,044,300
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 3,000    
Components of Net Periodic Benefit Cost      
Service Cost 4,600 7,400 9,500
Interest Cost 46,200 29,200 30,500
Expected Return on Plan Assets (109,600) (110,000) (91,100)
Amortization of Prior Service Cost (Credit) (63,100) (71,400) (70,900)
Amortization of Net Actuarial Loss 14,800    
Net Periodic Benefit Cost (Credit) (107,100) (144,800) (122,000)
Capitalized Portion (2,100) (3,200) (4,100)
Net Periodic Benefit Cost (Credit) Recognized in Expense (109,200) (148,000) (126,100)
Other Postretirement Benefit Plans [Member] | Benefit Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 117,200    
Year Two 122,600    
Year Three 122,400    
Year Four 121,500    
Year Five 120,200    
After Year Five for Next Five Years, in Total 566,100    
Other Postretirement Benefit Plans [Member] | Medicare Subsidy Receipts [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 300    
Year Two 300    
Year Three 300    
Year Four 300    
Year Five 300    
After Year Five for Next Five Years, in Total 1,500    
Other Postretirement Benefit Plans [Member] | AEP Texas Inc. [Member]      
Underfunded Benefit Obligation      
Projected Benefit Obligation 66,400 68,600 80,500
Fair Value of Plan Assets 137,500 128,300 168,800
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 0    
Components of Net Periodic Benefit Cost      
Service Cost 300 500 700
Interest Cost 3,600 2,200 2,400
Expected Return on Plan Assets (9,000) (9,100) (7,500)
Amortization of Prior Service Cost (Credit) (5,300) (6,100) (6,000)
Amortization of Net Actuarial Loss 1,200    
Net Periodic Benefit Cost (Credit) (9,200) (12,500) (10,400)
Capitalized Portion (200) (300) (400)
Net Periodic Benefit Cost (Credit) Recognized in Expense (9,400) (12,800) (10,800)
Other Postretirement Benefit Plans [Member] | AEP Texas Inc. [Member] | Benefit Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 9,400    
Year Two 10,000    
Year Three 10,200    
Year Four 10,200    
Year Five 9,900    
After Year Five for Next Five Years, in Total 45,200    
Other Postretirement Benefit Plans [Member] | AEP Texas Inc. [Member] | Medicare Subsidy Receipts [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 0    
Year Two 0    
Year Three 0    
Year Four 0    
Year Five 0    
After Year Five for Next Five Years, in Total 0    
Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]      
Underfunded Benefit Obligation      
Projected Benefit Obligation 134,600 140,700 167,300
Fair Value of Plan Assets 243,000 228,600 302,300
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 1,600    
Components of Net Periodic Benefit Cost      
Service Cost 500 800 1,000
Interest Cost 7,400 4,700 4,900
Expected Return on Plan Assets (16,100) (16,300) (13,500)
Amortization of Prior Service Cost (Credit) (9,200) (10,400) (10,300)
Amortization of Net Actuarial Loss 2,300    
Net Periodic Benefit Cost (Credit) (15,100) (21,200) (17,900)
Capitalized Portion (200) (400) (400)
Net Periodic Benefit Cost (Credit) Recognized in Expense (15,300) (21,600) (18,300)
Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member] | Benefit Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 18,800    
Year Two 19,400    
Year Three 19,300    
Year Four 19,100    
Year Five 19,000    
After Year Five for Next Five Years, in Total 88,300    
Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member] | Medicare Subsidy Receipts [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 100    
Year Two 100    
Year Three 100    
Year Four 100    
Year Five 100    
After Year Five for Next Five Years, in Total 500    
Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]      
Underfunded Benefit Obligation      
Projected Benefit Obligation 98,800 101,900 118,600
Fair Value of Plan Assets 204,600 190,500 248,700
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 0    
Components of Net Periodic Benefit Cost      
Service Cost 600 900 1,300
Interest Cost 5,400 3,400 3,500
Expected Return on Plan Assets (13,500) (13,700) (11,100)
Amortization of Prior Service Cost (Credit) (8,700) (9,700) (9,600)
Amortization of Net Actuarial Loss 1,900    
Net Periodic Benefit Cost (Credit) (14,300) (19,100) (15,900)
Capitalized Portion (200) (300) (400)
Net Periodic Benefit Cost (Credit) Recognized in Expense (14,500) (19,400) (16,300)
Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member] | Benefit Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 15,200    
Year Two 15,700    
Year Three 15,700    
Year Four 15,400    
Year Five 15,000    
After Year Five for Next Five Years, in Total 69,700    
Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member] | Medicare Subsidy Receipts [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 0    
Year Two 0    
Year Three 0    
Year Four 0    
Year Five 0    
After Year Five for Next Five Years, in Total 0    
Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]      
Underfunded Benefit Obligation      
Projected Benefit Obligation 85,900 88,900 104,900
Fair Value of Plan Assets 177,800 166,200 220,000
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 0    
Components of Net Periodic Benefit Cost      
Service Cost 400 600 800
Interest Cost 4,700 3,000 3,000
Expected Return on Plan Assets (11,800) (12,000) (9,700)
Amortization of Prior Service Cost (Credit) (6,300) (7,100) (7,200)
Amortization of Net Actuarial Loss 1,600    
Net Periodic Benefit Cost (Credit) (11,400) (15,500) (13,100)
Capitalized Portion (200) (300) (400)
Net Periodic Benefit Cost (Credit) Recognized in Expense (11,600) (15,800) (13,500)
Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member] | Benefit Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 12,600    
Year Two 13,000    
Year Three 12,800    
Year Four 12,700    
Year Five 12,500    
After Year Five for Next Five Years, in Total 57,600    
Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member] | Medicare Subsidy Receipts [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 0    
Year Two 0    
Year Three 0    
Year Four 0    
Year Five 0    
After Year Five for Next Five Years, in Total 0    
Other Postretirement Benefit Plans [Member] | Public Service Co Of Oklahoma [Member]      
Underfunded Benefit Obligation      
Projected Benefit Obligation 43,700 45,700 54,400
Fair Value of Plan Assets 90,200 85,400 114,000
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 0    
Components of Net Periodic Benefit Cost      
Service Cost 300 400 600
Interest Cost 2,400 1,500 1,600
Expected Return on Plan Assets (5,900) (6,100) (5,000)
Amortization of Prior Service Cost (Credit) (4,000) (4,400) (4,400)
Amortization of Net Actuarial Loss 800    
Net Periodic Benefit Cost (Credit) (6,400) (8,600) (7,200)
Capitalized Portion (100) (200) (300)
Net Periodic Benefit Cost (Credit) Recognized in Expense (6,500) (8,800) (7,500)
Other Postretirement Benefit Plans [Member] | Public Service Co Of Oklahoma [Member] | Benefit Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 6,700    
Year Two 7,100    
Year Three 7,000    
Year Four 6,800    
Year Five 6,500    
After Year Five for Next Five Years, in Total 30,200    
Other Postretirement Benefit Plans [Member] | Public Service Co Of Oklahoma [Member] | Medicare Subsidy Receipts [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 0    
Year Two 0    
Year Three 0    
Year Four 0    
Year Five 0    
After Year Five for Next Five Years, in Total 0    
Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]      
Underfunded Benefit Obligation      
Projected Benefit Obligation 53,700 55,100 65,200
Fair Value of Plan Assets 111,100 103,000 136,600
Estimated Future Benefit Payments and Contributions      
Expected Contributions and Payments During 2024 0    
Components of Net Periodic Benefit Cost      
Service Cost 400 600 800
Interest Cost 2,900 1,800 1,900
Expected Return on Plan Assets (7,200) (7,300) (6,100)
Amortization of Prior Service Cost (Credit) (4,900) (5,300) (5,300)
Amortization of Net Actuarial Loss 1,000    
Net Periodic Benefit Cost (Credit) (7,800) (10,200) (8,700)
Capitalized Portion (200) (200) (300)
Net Periodic Benefit Cost (Credit) Recognized in Expense (8,000) $ (10,400) $ (9,000)
Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member] | Benefit Payments [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 7,800    
Year Two 8,300    
Year Three 8,300    
Year Four 8,100    
Year Five 8,200    
After Year Five for Next Five Years, in Total 38,800    
Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member] | Medicare Subsidy Receipts [Member]      
Estimated Future Benefit Payments and Contributions      
Year One 0    
Year Two 0    
Year Three 0    
Year Four 0    
Year Five 0    
After Year Five for Next Five Years, in Total $ 0