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Financing Activities (Details) - USD ($)
1 Months Ended 12 Months Ended
Feb. 20, 2020
Jan. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Shares of Company          
Beginning Balance, Shares   514,373,631 513,450,036 512,210,644 512,048,520
Issued     923,595 1,239,392 162,124
Ending Balance, Shares     514,373,631 513,450,036 512,210,644
Treasury Stock, Shares, Beginning Balance   20,204,160 20,204,160 20,205,046 20,336,592
Partners' Capital Account, Units, Treasury Units Reissued       (886) (131,546)
Treasury Stock, Shares, Ending Balance     20,204,160 20,204,160 20,205,046
Long-term Debt          
Senior Unsecured Notes     $ 21,180,700,000 $ 18,903,300,000  
Pollution Control Bonds     1,998,800,000 1,643,800,000  
Notes Payable     234,300,000 204,700,000  
Securitization Bonds     1,025,100,000 1,111,400,000  
Spent Nuclear Fuel Obligation     279,800,000 273,600,000  
Junior Subordinated Notes     787,800,000 0  
Other Long-term Debt     1,219,000,000.0 1,209,900,000  
Total Long-term Debt Outstanding     26,725,500,000 23,346,700,000  
Outstanding Long-term Debt          
Principal Amount, 2020     1,598,700,000    
Principal Amount, 2021     2,022,700,000    
Principal Amount, 2022     3,014,600,000    
Principal Amount, 2023     739,900,000    
Principal Amount, 2024     706,500,000    
Principal Amount, After 2024     18,863,100,000    
Principal Amount, Total     26,945,500,000    
Unamortized Discount, Net and Debt Issuance Costs     (220,000,000.0)    
Total Long-term Debt Outstanding     26,725,500,000 23,346,700,000  
Short-term Debt          
Securitized Debt for Receivables     710,000,000.0 750,000,000.0  
Commercial Paper     2,110,000,000.0 1,160,000,000.0  
Notes Payable     18,300,000 0  
Total Short-term Debt     $ 2,838,300,000 $ 1,910,000,000.0  
Securitized Debt for Receivables     2.42% 2.16%  
Comparative Accounts Receivable Information          
Effective Interest Rates on Securitization of Accounts Receivable     2.42% 2.16% 1.22%
Net Uncollectible Accounts Receivable Written Off     $ 26,600,000 $ 27,600,000 $ 23,400,000
Customer Accounts Receivable Managed Portfolio          
Accounts Receivable Retained Interest and Pledged as Collateral Less Uncollectible Accounts     841,800,000 972,500,000  
Total Principal Outstanding     710,000,000.0 750,000,000.0  
Delinquent Securitized Accounts Receivable     39,600,000 50,300,000  
Bad Debt Reserves Related to Securitized Sale of Accounts Receivable     32,100,000 27,500,000  
Unbilled Receivables Related to Securitization, Sale of Accounts Receivable     266,800,000 281,400,000  
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     15,561,400,000 16,195,700,000 15,424,900,000
Financing Activities (Textuals)          
Reaquired Pollution Control Bonds Held by Trustees     35,000,000    
Repayments of Long-term Debt     1,220,800,000 2,782,000,000.0 3,087,900,000
Proceeds from Issuance of Long-term Debt     $ 4,536,600,000 4,945,700,000 3,854,100,000
Equity Units Issued     16,100,000    
Per Unit Conversion for Equity Units     $ 50    
Net Equity Units Issuance Proceeds     785,000,000    
Principal Amounts of Junior Subordinated Debt     $ 1,000    
Forward Equity Purchase Contract Date     2024    
Equity Units Annual Distribution Rate     6.125%    
Forward Equity Contract Payment Rate     2.725%    
Stockholders' Equity, Other     $ (7,600,000) 23,100,000 55,800,000
Maximum Shares Issued Under Equity Units Conversion     9,701,860    
Maximum Percentage Debt to Capitalization     67.50%    
Restricted Net Assets     $ 13,200,000,000    
Dividend Restrictions     1,741,400,000    
Retained Earnings Available to Pay Dividends     7,200,000,000    
Dividends Paid on Common Stock     (1,350,000,000.0) $ (1,255,500,000) (1,191,900,000)
Credit Facilities, Total     $ 4,000,000,000    
Weighted Average Interest Rate of Commercial Paper Outstanding During Year     2.51%    
Maximum Amount of Commercial Paper Outstanding     $ 2,200,000,000    
Total Commitment From Bank Conduits To Finance Receivables     $ 750,000,000    
Minimum [Member]          
Financing Activities (Textuals)          
AEP Share Price for Equity Unit Conversion     $ 82.98    
Shares Per Equity Unit     0.5021    
Maximum [Member]          
Financing Activities (Textuals)          
AEP Share Price for Equity Unit Conversion     $ 99.58    
Shares Per Equity Unit     0.6026    
Commercial Paper [Member]          
Short-term Debt          
Debt, Weighted Average Interest Rate     2.10% 2.96%  
Loans Payable [Member]          
Short-term Debt          
Debt, Weighted Average Interest Rate     3.29% 0.00%  
AEP Texas Inc. [Member]          
Long-term Debt          
Senior Unsecured Notes     $ 3,090,900,000 $ 2,398,400,000  
Pollution Control Bonds     490,300,000 490,900,000  
Securitization Bonds     776,800,000 791,200,000  
Other Long-term Debt     200,400,000 200,800,000  
Total Long-term Debt Outstanding     4,558,400,000 3,881,300,000  
Outstanding Long-term Debt          
Principal Amount, 2020     392,100,000    
Principal Amount, 2021     88,700,000    
Principal Amount, 2022     716,000,000.0    
Principal Amount, 2023     218,500,000    
Principal Amount, 2024     96,000,000.0    
Principal Amount, After 2024     3,081,400,000    
Principal Amount, Total     4,592,700,000    
Unamortized Discount, Net and Debt Issuance Costs     (34,300,000)    
Total Long-term Debt Outstanding     4,558,400,000 3,881,300,000  
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     1,551,600,000 1,493,000,000.0  
Financing Activities (Textuals)          
Repayments of Long-term Debt     401,800,000 266,100,000 323,100,000
Proceeds from Issuance of Long-term Debt     $ 1,070,400,000 494,000,000.0 $ 749,600,000
Maximum Percentage Debt to Capitalization     67.50%    
Dividend Restrictions     $ 385,000,000.0    
AEP Texas Inc. [Member] | Utility [Member]          
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Borrowings from Money Pool     390,700,000 390,600,000  
Maximum Loans to Money Pool     213,100,000 106,900,000  
Average Borrowings from Money Pool     239,300,000 176,000,000.0  
Average Loans to Money Pool     194,400,000 47,100,000  
Net Loans (Borrowings) to/from Money Pool     199,700,000 (216,000,000.0)  
Authorized Short Term Borrowing Limit     $ 500,000,000.0 $ 500,000,000.0  
Maximum and Minimum Interest Rates          
Maximum Interest Rate     3.43% 2.97% 1.85%
Minimum Interest Rate     1.77% 1.81% 0.92%
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Borrowed     2.63% 2.26% 1.29%
Average Interest Rate For Funds Loaned     2.03% 2.29% 1.26%
AEP Texas Inc. [Member] | Nonutility [Member]          
Maximum Interest Rate For Funds Loaned     3.02% 2.97% 1.85%
Minimum Interest Rate for Funds Loaned     1.91% 1.83% 0.00%
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Loans to Money Pool     $ 8,000,000.0 $ 8,400,000  
Average Loans to Money Pool     7,700,000 8,100,000  
Net Loans (Borrowings) to/from Money Pool     $ 7,500,000 $ 8,000,000.0  
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Loaned     2.56% 2.36% 1.32%
AEP Transmission Co [Member]          
Long-term Debt          
Senior Unsecured Notes     $ 3,427,300,000 $ 2,823,000,000.0  
Total Long-term Debt Outstanding     3,427,300,000 2,823,000,000.0  
Outstanding Long-term Debt          
Principal Amount, 2020     0    
Principal Amount, 2021     50,000,000.0    
Principal Amount, 2022     104,000,000.0    
Principal Amount, 2023     60,000,000.0    
Principal Amount, 2024     95,000,000.0    
Principal Amount, After 2024     3,156,000,000.0    
Principal Amount, Total     3,465,000,000.0    
Unamortized Discount, Net and Debt Issuance Costs     (37,700,000)    
Total Long-term Debt Outstanding     3,427,300,000 2,823,000,000.0  
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     1,042,100,000 832,000,000.0  
Financing Activities (Textuals)          
Repayments of Long-term Debt     85,000,000.0 50,000,000.0 $ 0
Proceeds from Issuance of Long-term Debt     688,000,000.0 321,000,000.0 $ 617,600,000
Sub-Limit of Secured Debt     $ 50,000,000    
Maximum Percentage of Consolidated Tangible Net Assets     10.00%    
Tangible Capital to Tangible Assets     1.60%    
Maximum Percentage Debt to Capitalization     67.50%    
Dividend Restrictions     $ 0    
AEP Transmission Co [Member] | Utility [Member]          
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Borrowings from Money Pool     374,900,000 371,300,000  
Maximum Loans to Money Pool     244,400,000 276,400,000  
Average Borrowings from Money Pool     152,000,000.0 177,900,000  
Average Loans to Money Pool     52,800,000 58,400,000  
Net Loans (Borrowings) to/from Money Pool     (119,000,000.0) 35,800,000  
Authorized Short Term Borrowing Limit     $ 795,000,000.0 $ 795,000,000.0  
Maximum and Minimum Interest Rates          
Maximum Interest Rate     3.43% 2.97% 1.85%
Minimum Interest Rate     1.77% 1.81% 0.92%
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Borrowed     2.64% 2.27% 1.36%
Average Interest Rate For Funds Loaned     2.41% 2.10% 1.27%
AEP Transmission Co [Member] | Direct Borrowing [Member]          
Maximum Interest Rate for Funds Borrowed     3.02% 2.97% 1.85%
Minimum Interest Rate For Funds Borrowed     1.91% 1.76% 0.92%
Maximum Interest Rate For Funds Loaned     3.02% 2.97% 1.85%
Minimum Interest Rate for Funds Loaned     1.91% 1.76% 0.92%
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Borrowings from Money Pool     $ 1,300,000 $ 1,200,000  
Maximum Loans to Money Pool     153,500,000 104,700,000  
Average Borrowings from Money Pool     1,300,000 1,100,000  
Average Loans to Money Pool     68,000,000.0 49,800,000  
Borrowings from Parent     1,300,000 1,200,000  
Loans to Parent     68,700,000 16,900,000  
Authorized Short Term Borrowing Limit     $ 75,000,000.0 $ 75,000,000.0  
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Borrowed     2.55% 2.36% 1.33%
Average Interest Rate For Funds Loaned     2.51% 2.36% 1.36%
Appalachian Power Co [Member]          
Long-term Debt          
Senior Unsecured Notes     $ 3,442,700,000 $ 3,047,300,000  
Pollution Control Bonds     546,100,000 616,000,000.0  
Securitization Bonds     248,300,000 272,300,000  
Other Long-term Debt     126,700,000 127,000,000.0  
Total Long-term Debt Outstanding     4,363,800,000 4,062,600,000  
Outstanding Long-term Debt          
Principal Amount, 2020     215,600,000    
Principal Amount, 2021     393,000,000.0    
Principal Amount, 2022     355,400,000    
Principal Amount, 2023     26,600,000    
Principal Amount, 2024     113,500,000    
Principal Amount, After 2024     3,296,900,000    
Principal Amount, Total     4,401,000,000.0    
Unamortized Discount, Net and Debt Issuance Costs     (37,200,000)    
Total Long-term Debt Outstanding     4,363,800,000 4,062,600,000  
Accounts Receivable and Accrued Unbilled Revenue          
Accounts Receivable and Accrued Unbilled Revenues     120,900,000 133,300,000  
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     2,911,100,000 2,993,200,000  
Proceeds on Sale of Receivables to AEP Credit          
Proceeds from Sale of Receivables to AEP Credit     1,310,300,000 1,421,000,000.0 $ 1,372,800,000
Financing Activities (Textuals)          
Repayments of Long-term Debt     180,500,000 124,000,000.0 377,900,000
Proceeds from Issuance of Long-term Debt     $ 478,200,000 203,200,000 $ 320,900,000
Maximum Percentage Debt to Capitalization     67.50%    
Dividend Restrictions     $ 26,300,000    
Appalachian Power Co [Member] | Utility [Member]          
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Borrowings from Money Pool     270,000,000.0 295,500,000  
Maximum Loans to Money Pool     232,200,000 23,700,000  
Average Borrowings from Money Pool     115,900,000 175,300,000  
Average Loans to Money Pool     51,900,000 23,300,000  
Net Loans (Borrowings) to/from Money Pool     (214,600,000) (182,600,000)  
Authorized Short Term Borrowing Limit     $ 500,000,000.0 $ 600,000,000.0  
Maximum and Minimum Interest Rates          
Maximum Interest Rate     3.43% 2.97% 1.85%
Minimum Interest Rate     1.77% 1.81% 0.92%
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Borrowed     2.45% 2.26% 1.28%
Average Interest Rate For Funds Loaned     2.66% 2.21% 1.29%
Indiana Michigan Power Co [Member]          
Long-term Debt          
Senior Unsecured Notes     $ 2,150,700,000 $ 2,149,000,000.0  
Pollution Control Bonds     240,000,000.0 264,500,000  
Notes Payable     168,700,000 135,800,000  
Spent Nuclear Fuel Obligation     279,800,000 273,600,000  
Other Long-term Debt     211,000,000.0 212,500,000  
Total Long-term Debt Outstanding     3,050,200,000 3,035,400,000  
Outstanding Long-term Debt          
Principal Amount, 2020     139,700,000    
Principal Amount, 2021     291,500,000    
Principal Amount, 2022     26,800,000    
Principal Amount, 2023     259,200,000    
Principal Amount, 2024     4,200,000    
Principal Amount, After 2024     2,355,300,000    
Principal Amount, Total     3,076,700,000    
Unamortized Discount, Net and Debt Issuance Costs     (26,500,000)    
Total Long-term Debt Outstanding     3,050,200,000 3,035,400,000  
Accounts Receivable and Accrued Unbilled Revenue          
Accounts Receivable and Accrued Unbilled Revenues     141,800,000 152,900,000  
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     2,308,100,000 2,381,000,000.0  
Proceeds on Sale of Receivables to AEP Credit          
Proceeds from Sale of Receivables to AEP Credit     1,824,200,000 1,843,000,000.0 $ 1,612,900,000
Financing Activities (Textuals)          
Repayments of Long-term Debt     117,100,000 884,900,000 260,700,000
Proceeds from Issuance of Long-term Debt     $ 123,300,000 1,168,100,000 $ 530,100,000
Maximum Percentage Debt to Capitalization     67.50%    
Dividend Restrictions     $ 524,500,000    
Indiana Michigan Power Co [Member] | Utility [Member]          
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Borrowings from Money Pool     158,800,000 322,100,000  
Maximum Loans to Money Pool     66,000,000.0 657,800,000  
Average Borrowings from Money Pool     71,500,000 255,500,000  
Average Loans to Money Pool     16,200,000 110,700,000  
Net Loans (Borrowings) to/from Money Pool     (101,200,000) 11,600,000  
Authorized Short Term Borrowing Limit     $ 500,000,000.0 $ 500,000,000.0  
Maximum and Minimum Interest Rates          
Maximum Interest Rate     3.43% 2.97% 1.85%
Minimum Interest Rate     1.77% 1.81% 0.92%
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Borrowed     2.34% 2.16% 1.27%
Average Interest Rate For Funds Loaned     2.60% 2.08% 1.29%
Ohio Power Co [Member]          
Long-term Debt          
Senior Unsecured Notes     $ 2,081,000,000.0 $ 1,635,500,000  
Pollution Control Bonds     0 32,300,000  
Securitization Bonds     0 47,800,000  
Other Long-term Debt     1,000,000.0 1,000,000.0  
Total Long-term Debt Outstanding     2,082,000,000.0 1,716,600,000  
Outstanding Long-term Debt          
Principal Amount, 2020     100,000    
Principal Amount, 2021     500,100,000    
Principal Amount, 2022     100,000    
Principal Amount, 2023     100,000    
Principal Amount, 2024     100,000    
Principal Amount, After 2024     1,600,500,000    
Principal Amount, Total     2,101,000,000.0    
Unamortized Discount, Net and Debt Issuance Costs     (19,000,000.0)    
Total Long-term Debt Outstanding     2,082,000,000.0 1,716,600,000  
Accounts Receivable and Accrued Unbilled Revenue          
Accounts Receivable and Accrued Unbilled Revenues     330,300,000 395,200,000  
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     2,748,800,000 3,079,900,000  
Proceeds on Sale of Receivables to AEP Credit          
Proceeds from Sale of Receivables to AEP Credit     2,293,600,000 2,674,500,000 $ 2,339,000,000.0
Financing Activities (Textuals)          
Reaquired Pollution Control Bonds Held by Trustees     35,000,000    
Repayments of Long-term Debt     80,300,000 397,100,000 46,400,000
Proceeds from Issuance of Long-term Debt     444,300,000 392,800,000 $ 0
Dividend Restrictions     0    
Ohio Power Co [Member] | Utility [Member]          
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Borrowings from Money Pool     291,200,000 270,800,000  
Maximum Loans to Money Pool     178,600,000 225,000,000.0  
Average Borrowings from Money Pool     129,200,000 167,800,000  
Average Loans to Money Pool     50,100,000 189,400,000  
Net Loans (Borrowings) to/from Money Pool     (131,000,000.0) (114,100,000)  
Authorized Short Term Borrowing Limit     $ 500,000,000.0 $ 500,000,000.0  
Maximum and Minimum Interest Rates          
Maximum Interest Rate     3.43% 2.97% 1.85%
Minimum Interest Rate     1.77% 1.81% 0.92%
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Borrowed     2.67% 2.18% 1.37%
Average Interest Rate For Funds Loaned     2.68% 2.47% 0.98%
Public Service Co Of Oklahoma [Member]          
Shares of Company          
Beginning Balance, Shares   10,482,000 10,482,000    
Ending Balance, Shares     10,482,000 10,482,000  
Long-term Debt          
Senior Unsecured Notes     $ 1,245,600,000 $ 1,144,900,000  
Pollution Control Bonds     12,700,000 12,600,000  
Other Long-term Debt     127,900,000 129,500,000  
Total Long-term Debt Outstanding     1,386,200,000 1,287,000,000.0  
Outstanding Long-term Debt          
Principal Amount, 2020     13,200,000    
Principal Amount, 2021     250,500,000    
Principal Amount, 2022     125,500,000    
Principal Amount, 2023     600,000    
Principal Amount, 2024     600,000    
Principal Amount, After 2024     1,001,400,000    
Principal Amount, Total     1,391,800,000    
Unamortized Discount, Net and Debt Issuance Costs     (5,600,000)    
Total Long-term Debt Outstanding     1,386,200,000 1,287,000,000.0  
Accounts Receivable and Accrued Unbilled Revenue          
Accounts Receivable and Accrued Unbilled Revenues     101,100,000 109,700,000  
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     1,512,800,000 1,536,400,000  
Proceeds on Sale of Receivables to AEP Credit          
Proceeds from Sale of Receivables to AEP Credit     1,442,500,000 1,484,600,000 $ 1,337,000,000.0
Financing Activities (Textuals)          
Repayments of Long-term Debt     250,500,000 500,000 500,000
Proceeds from Issuance of Long-term Debt     $ 349,500,000 0 $ 0
Maximum Percentage Debt to Capitalization     67.50%    
Dividend Restrictions     $ 153,000,000.0    
Public Service Co Of Oklahoma [Member] | Utility [Member]          
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Borrowings from Money Pool     140,500,000 193,700,000  
Maximum Loans to Money Pool     215,600,000 31,800,000  
Average Borrowings from Money Pool     63,900,000 104,500,000  
Average Loans to Money Pool     98,300,000 12,900,000  
Net Loans (Borrowings) to/from Money Pool     38,800,000 (105,500,000)  
Authorized Short Term Borrowing Limit     $ 300,000,000.0 $ 300,000,000.0  
Maximum and Minimum Interest Rates          
Maximum Interest Rate     3.43% 2.97% 1.85%
Minimum Interest Rate     1.77% 1.81% 0.92%
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Borrowed     2.85% 2.27% 1.32%
Average Interest Rate For Funds Loaned     2.27% 1.98% 0.00%
Southwestern Electric Power Co [Member]          
Long-term Debt          
Senior Unsecured Notes     $ 2,428,900,000 $ 2,427,000,000.0  
Pollution Control Bonds     0 53,500,000  
Notes Payable     65,600,000 68,900,000  
Other Long-term Debt     161,100,000 164,000,000.0  
Total Long-term Debt Outstanding     2,655,600,000 2,713,400,000  
Outstanding Long-term Debt          
Principal Amount, 2020     121,200,000    
Principal Amount, 2021     6,200,000    
Principal Amount, 2022     281,200,000    
Principal Amount, 2023     6,200,000    
Principal Amount, 2024     31,200,000    
Principal Amount, After 2024     2,231,700,000    
Principal Amount, Total     2,677,700,000    
Unamortized Discount, Net and Debt Issuance Costs     (22,100,000)    
Total Long-term Debt Outstanding     2,655,600,000 2,713,400,000  
Short-term Debt          
Notes Payable     18,300,000 0  
Accounts Receivable and Accrued Unbilled Revenue          
Accounts Receivable and Accrued Unbilled Revenues     125,200,000 150,300,000  
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     1,799,200,000 1,817,000,000.0  
Proceeds on Sale of Receivables to AEP Credit          
Proceeds from Sale of Receivables to AEP Credit     1,618,500,000 1,736,100,000 $ 1,563,400,000
Financing Activities (Textuals)          
Repayments of Long-term Debt     59,700,000 794,500,000 353,700,000
Proceeds from Issuance of Long-term Debt     $ 0 1,065,700,000 114,600,000
Maximum Percentage Debt to Capitalization     67.50%    
Dividend Restrictions     $ 534,500,000    
Dividends Paid on Common Stock     (3,300,000) (4,300,000) $ (13,600,000)
Southwestern Electric Power Co [Member] | Utility [Member]          
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Borrowings from Money Pool     105,100,000 200,100,000  
Maximum Loans to Money Pool     81,400,000 533,700,000  
Average Borrowings from Money Pool     53,300,000 143,200,000  
Average Loans to Money Pool     13,600,000 268,100,000  
Net Loans (Borrowings) to/from Money Pool     (59,900,000) 81,400,000  
Authorized Short Term Borrowing Limit     $ 350,000,000.0 $ 350,000,000.0  
Maximum and Minimum Interest Rates          
Maximum Interest Rate     3.43% 2.97% 1.85%
Minimum Interest Rate     1.77% 1.81% 0.92%
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Borrowed     2.72% 2.31% 1.28%
Average Interest Rate For Funds Loaned     2.22% 2.00% 0.98%
Southwestern Electric Power Co [Member] | Nonutility [Member]          
Maximum Interest Rate For Funds Loaned     3.02% 2.97% 1.85%
Minimum Interest Rate for Funds Loaned     1.91% 1.83% 0.00%
Money Pool Participants' Money Pool Activity and Authorized Borrowing Limits          
Maximum Loans to Money Pool     $ 2,100,000 $ 2,000,000.0  
Average Loans to Money Pool     2,000,000.0 2,000,000.0  
Net Loans (Borrowings) to/from Money Pool     $ 2,100,000 $ 2,000,000.0  
Average Interest Rates for Funds Borrowed from and Loaned to Money Pool          
Average Interest Rate For Funds Loaned     2.55% 2.36% 1.32%
Southwestern Electric Power Co [Member] | Loans Payable [Member]          
Short-term Debt          
Debt, Weighted Average Interest Rate     3.29% 0.00%  
Senior Notes [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2050    
Weighted Average Interest Rate     4.29%    
Senior Notes [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     2.15% 2.15%  
Senior Notes [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     8.13% 8.13%  
Senior Notes [Member] | AEP Texas Inc. [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2050    
Weighted Average Interest Rate     4.01%    
Senior Notes [Member] | AEP Texas Inc. [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     2.40% 2.40%  
Senior Notes [Member] | AEP Texas Inc. [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     6.76% 6.76%  
Senior Notes [Member] | AEP Transmission Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2049    
Weighted Average Interest Rate     3.86%    
Senior Notes [Member] | AEP Transmission Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.10% 2.68%  
Senior Notes [Member] | AEP Transmission Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     5.52% 5.52%  
Senior Notes [Member] | Appalachian Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2021    
Maturity Date High     2049    
Weighted Average Interest Rate     5.12%    
Senior Notes [Member] | Appalachian Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.30% 3.30%  
Senior Notes [Member] | Appalachian Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     7.00% 7.00%  
Senior Notes [Member] | Indiana Michigan Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2023    
Maturity Date High     2048    
Weighted Average Interest Rate     4.38%    
Senior Notes [Member] | Indiana Michigan Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.20% 3.20%  
Senior Notes [Member] | Indiana Michigan Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     6.05% 6.05%  
Senior Notes [Member] | Ohio Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2021    
Maturity Date High     2049    
Weighted Average Interest Rate     5.20%    
Senior Notes [Member] | Ohio Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     4.00% 4.15%  
Senior Notes [Member] | Ohio Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     6.60% 6.60%  
Senior Notes [Member] | Public Service Co Of Oklahoma [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2049    
Weighted Average Interest Rate     4.55%    
Senior Notes [Member] | Public Service Co Of Oklahoma [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.05% 3.05%  
Senior Notes [Member] | Public Service Co Of Oklahoma [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     6.625% 6.625%  
Senior Notes [Member] | Southwestern Electric Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2022    
Maturity Date High     2048    
Weighted Average Interest Rate     4.04%    
Senior Notes [Member] | Southwestern Electric Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     2.75% 2.75%  
Senior Notes [Member] | Southwestern Electric Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     6.20% 6.20%  
Pollution Control Bonds [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low [1]     2019    
Maturity Date High [1]     2038    
Weighted Average Interest Rate     2.75%    
Pollution Control Bonds [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     1.35% 1.60%  
Pollution Control Bonds [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     5.38% 6.30%  
Pollution Control Bonds [Member] | AEP Texas Inc. [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2020    
Maturity Date High     2030    
Weighted Average Interest Rate     3.63%    
Pollution Control Bonds [Member] | AEP Texas Inc. [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     1.75% 1.75%  
Pollution Control Bonds [Member] | AEP Texas Inc. [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     4.55% 6.30%  
Pollution Control Bonds [Member] | Appalachian Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low [1]     2019    
Maturity Date High [1]     2038    
Weighted Average Interest Rate     2.64%    
Pollution Control Bonds [Member] | Appalachian Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     1.67% 1.70%  
Pollution Control Bonds [Member] | Appalachian Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     5.38% 5.38%  
Pollution Control Bonds [Member] | Indiana Michigan Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low [1]     2019    
Maturity Date High [1]     2025    
Weighted Average Interest Rate     2.55%    
Pollution Control Bonds [Member] | Indiana Michigan Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     1.79% 1.81%  
Pollution Control Bonds [Member] | Indiana Michigan Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.05% 3.05%  
Pollution Control Bonds [Member] | Ohio Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2038    
Maturity Date High     2038    
Pollution Control Bonds [Member] | Ohio Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate       5.80%  
Pollution Control Bonds [Member] | Ohio Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate       5.80%  
Pollution Control Bonds [Member] | Public Service Co Of Oklahoma [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2020    
Maturity Date High     2020    
Weighted Average Interest Rate     4.45%    
Pollution Control Bonds [Member] | Public Service Co Of Oklahoma [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     4.45% 4.45%  
Pollution Control Bonds [Member] | Public Service Co Of Oklahoma [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     4.45% 4.45%  
Pollution Control Bonds [Member] | Southwestern Electric Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2019    
Pollution Control Bonds [Member] | Southwestern Electric Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate       1.60%  
Pollution Control Bonds [Member] | Southwestern Electric Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate       1.60%  
Notes Payable, Other Payables [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2032    
Weighted Average Interest Rate     3.27%    
Notes Payable, Other Payables [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     2.42% 3.20%  
Notes Payable, Other Payables [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     6.37% 6.37%  
Notes Payable, Other Payables [Member] | Indiana Michigan Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2024    
Weighted Average Interest Rate     2.49%    
Notes Payable, Other Payables [Member] | Indiana Michigan Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     2.42% 3.20%  
Notes Payable, Other Payables [Member] | Indiana Michigan Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     2.80% 3.38%  
Notes Payable, Other Payables [Member] | Indiana Michigan Power Co [Member] | Subsequent Event [Member]          
Financing Activities (Textuals)          
Repayments of Long-term Debt $ 5,000,000 $ 8,000,000      
Notes Payable, Other Payables [Member] | Southwestern Electric Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2024    
Maturity Date High     2032    
Weighted Average Interest Rate     5.26%    
Notes Payable, Other Payables [Member] | Southwestern Electric Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     4.58% 4.58%  
Notes Payable, Other Payables [Member] | Southwestern Electric Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     6.37% 6.37%  
Securitization Bonds [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low [2]     2019    
Maturity Date High [2]     2029    
Weighted Average Interest Rate     3.23%    
Securitization Bonds [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     1.98% 1.98%  
Securitization Bonds [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     5.31% 5.31%  
Securitization Bonds [Member] | AEP Texas Inc. [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low [2]     2020    
Maturity Date High [2]     2029    
Weighted Average Interest Rate     3.25%    
Securitization Bonds [Member] | AEP Texas Inc. [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     1.98% 1.98%  
Securitization Bonds [Member] | AEP Texas Inc. [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     5.31% 5.31%  
Securitization Bonds [Member] | AEP Texas Inc. [Member] | Subsequent Event [Member]          
Financing Activities (Textuals)          
Repayments of Long-term Debt 3,000,000 111,000,000      
Securitization Bonds [Member] | Appalachian Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low [2]     2023    
Maturity Date High [2]     2028    
Weighted Average Interest Rate     3.17%    
Securitization Bonds [Member] | Appalachian Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     2.008% 2.008%  
Securitization Bonds [Member] | Appalachian Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.772% 3.772%  
Securitization Bonds [Member] | Appalachian Power Co [Member] | Subsequent Event [Member]          
Financing Activities (Textuals)          
Repayments of Long-term Debt $ 12,000,000        
Securitization Bonds [Member] | Ohio Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low [2]     2019    
Maturity Date High [2]     2019    
Securitization Bonds [Member] | Ohio Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate       2.049%  
Securitization Bonds [Member] | Ohio Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate       2.049%  
Junior Subordinated Notes [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2022    
Maturity Date High     2022    
Weighted Average Interest Rate     3.40%    
Financing Activities (Textuals)          
Proceeds from Issuance of Debt     $ 805,000,000    
Junior Subordinated Notes [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.40%  
Junior Subordinated Notes [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.40%  
Other Long Term Debt [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2059    
Weighted Average Interest Rate     3.03%    
Other Long Term Debt [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     1.15% 1.15%  
Other Long Term Debt [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     13.718% 13.718%  
Other Long Term Debt [Member] | AEP Texas Inc. [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2059    
Weighted Average Interest Rate     3.06%    
Other Long Term Debt [Member] | AEP Texas Inc. [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.05% 3.94%  
Other Long Term Debt [Member] | AEP Texas Inc. [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     4.50% 4.50%  
Other Long Term Debt [Member] | Appalachian Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2026    
Weighted Average Interest Rate     3.14%    
Other Long Term Debt [Member] | Appalachian Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     2.97% 3.74%  
Other Long Term Debt [Member] | Appalachian Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     13.718% 13.718%  
Other Long Term Debt [Member] | Indiana Michigan Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2021    
Maturity Date High     2025    
Weighted Average Interest Rate     3.09%    
Other Long Term Debt [Member] | Indiana Michigan Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     2.93% 3.66%  
Other Long Term Debt [Member] | Indiana Michigan Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     6.00% 6.00%  
Other Long Term Debt [Member] | Ohio Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2028    
Maturity Date High     2028    
Weighted Average Interest Rate     1.15%    
Other Long Term Debt [Member] | Ohio Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     1.15% 1.15%  
Other Long Term Debt [Member] | Ohio Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     1.15% 1.15%  
Other Long Term Debt [Member] | Public Service Co Of Oklahoma [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2019    
Maturity Date High     2027    
Weighted Average Interest Rate     3.19%    
Other Long Term Debt [Member] | Public Service Co Of Oklahoma [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.00% 3.00%  
Other Long Term Debt [Member] | Public Service Co Of Oklahoma [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.20% 3.72%  
Other Long Term Debt [Member] | Southwestern Electric Power Co [Member]          
Long- term Debt by Type of Debt and Maturity          
Maturity Date Low     2020    
Maturity Date High     2035    
Weighted Average Interest Rate     3.55%    
Other Long Term Debt [Member] | Southwestern Electric Power Co [Member] | Minimum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     3.08% 3.75%  
Other Long Term Debt [Member] | Southwestern Electric Power Co [Member] | Maximum [Member]          
Long- term Debt by Type of Debt and Maturity          
Interest Rate     4.68% 4.68%  
Other Long Term Debt [Member] | Transource Energy [Member] | Subsequent Event [Member]          
Financing Activities (Textuals)          
Proceeds from Issuance of Long-term Debt   $ 4,000,000      
Due Date   2023      
Servicing Contracts [Member] | Appalachian Power Co [Member]          
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     $ 7,400,000 $ 7,000,000.0 $ 5,600,000
Servicing Contracts [Member] | Indiana Michigan Power Co [Member]          
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     11,100,000 9,200,000 6,700,000
Servicing Contracts [Member] | Ohio Power Co [Member]          
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     27,100,000 26,300,000 21,700,000
Servicing Contracts [Member] | Public Service Co Of Oklahoma [Member]          
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     7,800,000 7,900,000 7,000,000.0
Servicing Contracts [Member] | Southwestern Electric Power Co [Member]          
Fees Paid to AEP Credit for Customer Accounts Receivable Sold          
Revenue from Contracts with Customers     10,200,000 8,900,000 7,200,000
Retained Earnings [Member]          
Financing Activities (Textuals)          
Stockholders' Equity, Other     62,000,000    
Dividends Paid on Common Stock     $ (1,300,000,000) $ (1,300,000,000) $ (1,200,000,000)
[1]
Certain Pollution Control Bonds are subject to redemption earlier than the maturity date.  Consequently, these bonds have been classified for maturity purposes as Long-term Debt Due Within One Year - Nonaffiliated on the balance sheets.
[2]
Dates represent the scheduled final payment dates for the securitization bonds. The legal maturity date is one to two years later. These bonds have been classified for maturity and repayment purposes based on the scheduled final payment date.