Financing Activities (Details) - USD ($)		1 Months Ended	3 Months Ended				6 Months Ended
		Jul. 25, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Long-term Debt
Senior Unsecured Notes			$ 20,468,900,000				$ 20,468,900,000		$ 18,903,300,000
Pollution Control Bonds			1,518,100,000				1,518,100,000		1,643,800,000
Notes Payable			216,900,000				216,900,000		204,700,000
Securitization Bonds			945,200,000				945,200,000		1,111,400,000
Spent Nuclear Fuel Obligation	[1]		277,000,000.0				277,000,000.0		273,600,000
Junior Subordinated Notes	[2]		786,100,000				786,100,000		0
Other Long-term Debt			1,219,600,000				1,219,600,000		1,209,900,000
Total Long-term Debt Outstanding			25,431,800,000				25,431,800,000		23,346,700,000
Long-term Debt Due Within One Year			1,257,400,000				1,257,400,000		1,698,500,000
Long-term Debt			24,174,400,000				24,174,400,000		21,648,200,000
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						2,816,400,000
Repayments of Long-term Debt							728,300,000	$ 1,339,800,000
Short-term Debt:
Securitized Debt for Receivables	[4]		692,000,000.0				692,000,000.0		750,000,000.0
Commercial Paper			1,585,000,000.0				1,585,000,000.0		1,160,000,000.0
Total Short-term Debt			$ 2,277,000,000.0				$ 2,277,000,000.0		$ 1,910,000,000.0
Securitized Debt for Receivables	[4],[5]		2.66%				2.66%		2.16%
Comparative Accounts Receivable Information
Effective Interest Rates on Securitization of Accounts Receivable			2.60%		2.16%		2.66%	1.95%
Net Uncollectible Accounts Receivable Written Off			$ 4,600,000		$ 5,300,000		$ 11,000,000.0	$ 9,400,000
Customer Accounts Receivable Managed Portfolio
Accounts Receivable Retained Interest and Pledged as Collateral Less Uncollectible Accounts			907,800,000				907,800,000		$ 972,500,000
Total Principal Outstanding			692,000,000.0				692,000,000.0		750,000,000.0
Delinquent Securitized Accounts Receivable			49,900,000				49,900,000		50,300,000
Bad Debt Reserves Related to Securitization, Sale of Accounts Receivable			32,500,000				32,500,000		27,500,000
Unbilled Receivables Related to Securitization, Sale of Accounts Receivable			298,500,000				298,500,000		281,400,000
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			3,573,600,000		4,013,200,000		7,630,400,000	8,061,500,000
Financing Activities (Textuals)
Trust Fund Assets One Time Fee Obligation for Nuclear Fuel Disposition			320,000,000				320,000,000		$ 317,000,000
Reacquired Pollution Controls Bonds Held by Trustees			574,000,000				$ 574,000,000
Maximum Percentage Debt to Capitalization							67.50%
Total Commitment from Bank Conduits to Finance Receivables			750,000,000				$ 750,000,000
Equity Units Issued							16,100,000
Per Unit Conversion for Equity Units			50				$ 50
Net Equity Units Issuance Proceeds							785,000,000
Principal Amounts of Junior Subordinated Debt			$ 1,000				$ 1,000
Equity Units Annual Distribution Rate			6.125%				6.125%
Forward Equity Contract Payment Rate			2.725%				2.725%
Stockholders' Equity, Other			$ 2,500,000	$ 55,600,000	1,500,000	$ (16,900,000)
Maximum Shares Issued Under Equity Units Conversion							9,701,860
Junior Subordinated Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3],[6]						$ 805,000,000.0
Due Date	[6]						2024
Interest Rate (Percentage)	[6]		3.40%				3.40%
Commercial Paper [Member]
Short-term Debt:
Weighted Average Interest Rate			2.67%				2.67%		2.96%
AEP Texas Inc. [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 3,994,600,000				$ 3,994,600,000		$ 3,881,300,000
Long-term Debt Due Within One Year			309,900,000				309,900,000		501,100,000
Long-term Debt			3,684,700,000				3,684,700,000		3,380,200,000
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 181,800,000	$ 154,100,000
Financing Activities (Textuals)
Maximum Percentage Debt to Capitalization							67.50%
AEP Texas Inc. [Member] | Utility [Member]
Maximum Interest Rate							3.02%	2.52%
Minimum Interest Rate							2.68%	1.83%
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Borrowings from Money Pool							$ 390,700,000
Maximum Loans to Money Pool							0
Average Borrowings from Money Pool							262,700,000
Average Loans to Money Pool							0
Net Loans (Borrowings) to/from Money Pool			(239,000,000.0)				(239,000,000.0)
Authorized Short Term Borrowing Limit							$ 500,000,000.0
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Borrowed							2.81%	2.28%
Average Interest Rate For Funds Loaned							0.00%	2.28%
AEP Texas Inc. [Member] | Nonutility [Member]
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Loans to Money Pool							$ 8,000,000.0
Average Loans to Money Pool							7,700,000
Net Loans (Borrowings) to/from Money Pool			$ 7,700,000				$ 7,700,000
Maximum and Minimum Interest Rates
Maximum Interest Rate For Funds Loaned							3.02%	2.52%
Minimum Interest Rate for Funds Loaned							2.68%	1.83%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Loaned							2.81%	2.23%
AEP Texas Inc. [Member] | Securitization Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 103,500,000
Due Date							2020
Interest Rate (Percentage)			5.31%				5.31%
AEP Texas Inc. [Member] | Securitization Bonds [Member] | Subsequent Event [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt		$ 84,000,000
AEP Texas Inc. [Member] | Securitization Bonds Two [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 28,300,000
Due Date							2020
Interest Rate (Percentage)			1.98%				1.98%
AEP Texas Inc. [Member] | Senior Unsecured Notes [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 300,000,000.0
Due Date							2049
Interest Rate (Percentage)			4.15%				4.15%
AEP Texas Inc. [Member] | Senior Unsecured Notes Two [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 50,000,000.0
Due Date							2019
Interest Rate (Percentage)			2.61%				2.61%
AEP Transmission Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 3,167,900,000				$ 3,167,900,000		2,823,000,000.0
Long-term Debt Due Within One Year			85,000,000.0				85,000,000.0		85,000,000.0
Long-term Debt			3,082,900,000				3,082,900,000		2,738,000,000.0
Financing Activities (Textuals)
Sub-Limit of Secured Debt			$ 50,000,000				$ 50,000,000
Maximum Percentage of Consolidated Tangible Net Assets			10.00%				10.00%
Tangible Capital to Tangible Assets			0.30%				0.30%
Maximum Percentage Debt to Capitalization							67.50%
AEP Transmission Co [Member] | Utility [Member]
Maximum Interest Rate							3.02%	2.52%
Minimum Interest Rate							2.68%	1.83%
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Borrowings from Money Pool							$ 374,900,000
Maximum Loans to Money Pool							80,000,000.0
Average Borrowings from Money Pool							215,700,000
Average Loans to Money Pool							29,200,000
Net Loans (Borrowings) to/from Money Pool			$ 14,700,000				14,700,000
Authorized Short Term Borrowing Limit	[7]						$ 795,000,000.0
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Borrowed							2.78%	2.30%
Average Interest Rate For Funds Loaned							2.83%	2.06%
AEP Transmission Co [Member] | Direct Borrowing [Member]
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Borrowings from Money Pool							$ 1,300,000
Maximum Loans to Money Pool							117,600,000
Average Borrowings from Money Pool							1,300,000
Average Loans to Money Pool							63,300,000
Borrowings from Parent			1,300,000				1,300,000
Loans to Parent			$ 17,300,000				17,300,000
Authorized Short Term Borrowing Limit	[8]						$ 75,000,000.0
Maximum and Minimum Interest Rates
Maximum Interest Rate for Funds Borrowed							3.02%	2.52%
Minimum Interest Rate For Funds Borrowed							2.68%	1.83%
Maximum Interest Rate For Funds Loaned							3.02%	2.52%
Minimum Interest Rate for Funds Loaned							2.68%	1.83%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Borrowed							2.81%	2.23%
Average Interest Rate For Funds Loaned							2.80%	2.23%
AEP Transmission Co [Member] | Senior Unsecured Notes [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 350,000,000.0
Due Date							2049
Interest Rate (Percentage)			3.80%				3.80%
Appalachian Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 4,374,800,000				$ 4,374,800,000		4,062,600,000
Long-term Debt Due Within One Year			150,000,000.0				150,000,000.0		430,700,000
Long-term Debt			4,224,800,000				4,224,800,000		3,631,900,000
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							168,000,000.0	$ 11,700,000
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			114,200,000				114,200,000		133,300,000
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			300,800,000		344,900,000		$ 675,200,000	745,100,000
Financing Activities (Textuals)
Maximum Percentage Debt to Capitalization							67.50%
Appalachian Power Co [Member] | Servicing Contracts [Member]
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			2,400,000		1,600,000		$ 4,600,000	$ 3,300,000
Appalachian Power Co [Member] | Utility [Member]
Maximum Interest Rate							3.02%	2.52%
Minimum Interest Rate							2.68%	1.83%
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Borrowings from Money Pool							$ 225,400,000
Maximum Loans to Money Pool							232,200,000
Average Borrowings from Money Pool							146,300,000
Average Loans to Money Pool							82,200,000
Net Loans (Borrowings) to/from Money Pool			$ (3,400,000)				(3,400,000)
Authorized Short Term Borrowing Limit							$ 600,000,000.0
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Borrowed							2.91%	2.23%
Average Interest Rate For Funds Loaned							2.77%	2.23%
Appalachian Power Co [Member] | Pollution Control Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 86,000,000.0
Due Date							2024
Interest Rate (Percentage)			2.55%				2.55%
Appalachian Power Co [Member] | Pollution Control Bonds Two [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 86,000,000.0
Due Date							2019
Interest Rate (Percentage)			1.90%				1.90%
Appalachian Power Co [Member] | Pollution Control Bonds Three [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 70,000,000.0
Due Date							2019
Interest Rate (Percentage)			3.25%				3.25%
Appalachian Power Co [Member] | Securitization Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 12,000,000.0
Due Date							2023
Interest Rate (Percentage)			2.01%				2.01%
Appalachian Power Co [Member] | Senior Unsecured Notes [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 400,000,000.0
Due Date							2049
Interest Rate (Percentage)			4.50%				4.50%
Indiana Michigan Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 3,054,500,000				$ 3,054,500,000		3,035,400,000
Long-term Debt Due Within One Year			155,100,000				155,100,000		155,400,000
Long-term Debt			2,899,400,000				2,899,400,000		2,880,000,000.0
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							48,300,000	$ 352,400,000
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			153,600,000				153,600,000		152,900,000
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			415,000,000.0		444,200,000		$ 893,600,000	903,300,000
Financing Activities (Textuals)
Maximum Percentage Debt to Capitalization							67.50%
Indiana Michigan Power Co [Member] | Servicing Contracts [Member]
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			3,200,000		2,200,000		$ 6,000,000.0	$ 4,300,000
Indiana Michigan Power Co [Member] | Utility [Member]
Maximum Interest Rate							3.02%	2.52%
Minimum Interest Rate							2.68%	1.83%
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Borrowings from Money Pool							$ 98,200,000
Maximum Loans to Money Pool							66,000,000.0
Average Borrowings from Money Pool							32,000,000.0
Average Loans to Money Pool							19,300,000
Net Loans (Borrowings) to/from Money Pool			$ (81,700,000)				(81,700,000)
Authorized Short Term Borrowing Limit							$ 500,000,000.0
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Borrowed							2.74%	2.16%
Average Interest Rate For Funds Loaned							2.82%	2.37%
Indiana Michigan Power Co [Member] | Notes Payable, Other Payables [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 62,800,000
Due Date							2023
Interest Rate (Variable)							Variable
Indiana Michigan Power Co [Member] | Notes Payable, Other Payables [Member] | Subsequent Event [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt		6,000,000
Indiana Michigan Power Co [Member] | Notes Payable, Other Payable Two [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 2,700,000
Due Date							2019
Interest Rate (Variable)							Variable
Indiana Michigan Power Co [Member] | Notes Payable, Other Payable Three [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 2,900,000
Due Date							2019
Interest Rate (Variable)							Variable
Indiana Michigan Power Co [Member] | Notes Payable, Other Payable Four [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 13,100,000
Due Date							2020
Interest Rate (Variable)							Variable
Indiana Michigan Power Co [Member] | Notes Payable, Other Payable Five [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 11,900,000
Due Date							2021
Interest Rate (Variable)							Variable
Indiana Michigan Power Co [Member] | Notes Payable, Other Payable Six [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 6,200,000
Due Date							2022
Interest Rate (Variable)							Variable
Indiana Michigan Power Co [Member] | Notes Payable, Other Payable Seven [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 10,600,000
Due Date							2022
Interest Rate (Variable)							Variable
Indiana Michigan Power Co [Member] | Notes Payable, Other Payable Eight [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 100,000
Due Date							2023
Interest Rate (Variable)							Variable
Indiana Michigan Power Co [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 800,000
Due Date							2025
Interest Rate (Percentage)			6.00%				6.00%
Ohio Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 2,138,200,000				$ 2,138,200,000		1,716,600,000
Long-term Debt Due Within One Year			24,700,000				24,700,000		47,900,000
Long-term Debt			2,113,500,000				2,113,500,000		1,668,700,000
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							23,400,000	$ 372,900,000
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			342,900,000				342,900,000		395,200,000
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			506,700,000		671,700,000		1,143,500,000	1,351,700,000
Financing Activities (Textuals)
Reacquired Pollution Controls Bonds Held by Trustees			345,000,000				345,000,000
Ohio Power Co [Member] | Servicing Contracts [Member]
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			7,900,000		6,000,000.0		$ 15,700,000	$ 11,600,000
Ohio Power Co [Member] | Utility [Member]
Maximum Interest Rate							3.02%	2.52%
Minimum Interest Rate							2.68%	1.83%
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Borrowings from Money Pool							$ 291,200,000
Maximum Loans to Money Pool							178,600,000
Average Borrowings from Money Pool							194,400,000
Average Loans to Money Pool							98,800,000
Net Loans (Borrowings) to/from Money Pool			$ 63,900,000				63,900,000
Authorized Short Term Borrowing Limit							$ 500,000,000.0
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Borrowed							2.81%	2.24%
Average Interest Rate For Funds Loaned							2.73%	2.47%
Ohio Power Co [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 100,000
Due Date							2028
Interest Rate (Percentage)			1.15%				1.15%
Ohio Power Co [Member] | Securitization Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 23,300,000
Due Date							2019
Interest Rate (Percentage)			2.05%				2.05%
Ohio Power Co [Member] | Securitization Bonds [Member] | Subsequent Event [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt		25,000,000
Ohio Power Co [Member] | Senior Unsecured Notes [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 450,000,000.0
Due Date							2049
Interest Rate (Percentage)			4.00%				4.00%
Public Service Co Of Oklahoma [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 1,386,300,000				$ 1,386,300,000		1,287,000,000.0
Long-term Debt Due Within One Year			138,100,000				138,100,000		375,500,000
Long-term Debt			1,248,200,000				1,248,200,000		911,500,000
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							250,200,000	$ 200,000
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			127,700,000				127,700,000		109,700,000
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			342,600,000		383,700,000		$ 667,100,000	716,400,000
Financing Activities (Textuals)
Maximum Percentage Debt to Capitalization							67.50%
Public Service Co Of Oklahoma [Member] | Servicing Contracts [Member]
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			2,100,000		1,900,000		$ 4,200,000	$ 3,700,000
Public Service Co Of Oklahoma [Member] | Utility [Member]
Maximum Interest Rate							3.02%	2.52%
Minimum Interest Rate							2.68%	1.83%
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Borrowings from Money Pool							$ 140,500,000
Maximum Loans to Money Pool							215,600,000
Average Borrowings from Money Pool							67,300,000
Average Loans to Money Pool							206,200,000
Net Loans (Borrowings) to/from Money Pool			$ (22,600,000)				(22,600,000)
Authorized Short Term Borrowing Limit							$ 300,000,000.0
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Borrowed							2.85%	2.24%
Average Interest Rate For Funds Loaned							2.74%	0.00%
Public Service Co Of Oklahoma [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 200,000
Due Date							2027
Interest Rate (Percentage)			3.00%				3.00%
Public Service Co Of Oklahoma [Member] | Senior Unsecured Notes [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 100,000,000.0
Due Date							2029
Interest Rate (Percentage)			3.91%				3.91%
Public Service Co Of Oklahoma [Member] | Senior Unsecured Notes Two [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 150,000,000.0
Due Date							2034
Interest Rate (Percentage)			4.11%				4.11%
Public Service Co Of Oklahoma [Member] | Senior Unsecured Notes Three [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 100,000,000.0
Due Date							2049
Interest Rate (Percentage)			4.50%				4.50%
Public Service Co Of Oklahoma [Member] | Senior Unsecured Notes Four [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 250,000,000.0
Due Date							2019
Interest Rate (Percentage)			5.15%				5.15%
Southwestern Electric Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 2,658,100,000				$ 2,658,100,000		2,713,400,000
Long-term Debt Due Within One Year			121,200,000				121,200,000		59,700,000
Long-term Debt			2,536,900,000				2,536,900,000		2,653,700,000
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							56,600,000	$ 383,500,000
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			153,700,000				153,700,000		$ 150,300,000
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			394,500,000		454,500,000		$ 766,400,000	852,000,000.0
Financing Activities (Textuals)
Maximum Percentage Debt to Capitalization							67.50%
Southwestern Electric Power Co [Member] | Servicing Contracts [Member]
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			3,400,000		$ 2,100,000		$ 6,000,000.0	$ 4,000,000.0
Southwestern Electric Power Co [Member] | Utility [Member]
Maximum Interest Rate							3.02%	2.52%
Minimum Interest Rate							2.68%	1.83%
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Borrowings from Money Pool							$ 105,100,000
Maximum Loans to Money Pool							81,400,000
Average Borrowings from Money Pool							67,000,000.0
Average Loans to Money Pool							24,000,000.0
Net Loans (Borrowings) to/from Money Pool			(55,300,000)				(55,300,000)
Authorized Short Term Borrowing Limit							$ 350,000,000.0
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Borrowed							2.77%	2.34%
Average Interest Rate For Funds Loaned							2.97%	1.88%
Southwestern Electric Power Co [Member] | Nonutility [Member]
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits
Maximum Loans to Money Pool							$ 2,000,000.0
Average Loans to Money Pool							2,000,000.0
Net Loans (Borrowings) to/from Money Pool			$ 2,000,000.0				$ 2,000,000.0
Maximum and Minimum Interest Rates
Maximum Interest Rate For Funds Loaned							3.02%	2.52%
Minimum Interest Rate for Funds Loaned							2.68%	1.83%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool
Average Interest Rate For Funds Loaned							2.81%	2.23%
Southwestern Electric Power Co [Member] | Notes Payable, Other Payables [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 1,600,000
Due Date							2032
Interest Rate (Percentage)			4.58%				4.58%
Southwestern Electric Power Co [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 1,500,000
Due Date							2028
Interest Rate (Percentage)			4.68%				4.68%
Southwestern Electric Power Co [Member] | Pollution Control Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Repayments of Long-term Debt							$ 53,500,000
Due Date							2019
Interest Rate (Percentage)			1.60%				1.60%
AEP Generating Co [Member] | Subsequent Event [Member]
Financing Activities (Textuals)
Reacquired Pollution Controls Bonds Held by Trustees		45,000,000
Transource Energy [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt	[3]						$ 12,600,000
Due Date							2020
Interest Rate (Variable)							Variable
Transource Energy [Member] | Other Long Term Debt [Member] | Subsequent Event [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Proceeds from Issuance of Debt		$ 2,000,000
July 2020 [Member]
Financing Activities (Textuals)
Commitment From Bank Conduits To Finance Receivables			$ 125,000,000				$ 125,000,000
July 2021 [Member]
Financing Activities (Textuals)
Commitment From Bank Conduits To Finance Receivables			$ 625,000,000				$ 625,000,000
Maximum [Member]
Financing Activities (Textuals)
AEP Share Price for Equity Unit Conversion			$ 99.58				$ 99.58
Shares Per Equity Unit			0.6026				0.6026
Minimum [Member]
Financing Activities (Textuals)
AEP Share Price for Equity Unit Conversion			$ 82.98				$ 82.98
Shares Per Equity Unit			0.5021				0.5021
Retained Earnings [Member]
Financing Activities (Textuals)
Stockholders' Equity, Other							$ 62,000,000

[1] Pursuant to the Nuclear Waste Policy Act of 1982, I&M, a nuclear licensee, has an obligation to the United States Department of Energy for SNF disposal.  The obligation includes a one-time fee for nuclear fuel consumed prior to April 7, 1983.  Trust fund assets related to this obligation were $320 million and $317 million as of June 30, 2019 and December 31, 2018, respectively, and are included in Spent Nuclear Fuel and Decommissioning Trusts on the balance sheets.

[2] See “Equity Units” section below for additional information.

[3] Amounts indicated on the statements of cash flows are net of issuance costs and premium or discount and will not tie to the issuance amounts.

[4] Amount of securitized debt for receivables as accounted for under the “Transfers and Servicing” accounting guidance.

[5] Weighted-average rate.

[6] See “Equity Units” section below for additional information.

[7] Amount represents the combined authorized short-term borrowing limit the State Transcos have from FERC or state regulatory commissions.

[8] Amount represents the combined authorized short-term borrowing limit the State Transcos have from FERC or state regulatory commissions.