Financing Activities (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended
		Apr. 28, 2016	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Long-term Debt
Senior Unsecured Notes			$ 14,026.2		$ 13,629.1
Pollution Control Bonds			1,784.1		1,784.8
Notes Payable			233.6		264.7
Securitization Bonds			1,863.1		2,024.0
Spent Nuclear Fuel Obligation	[1]		265.7		265.6
Other Long-term Debt			1,609.9		1,604.5
Total Long-term Debt Outstanding			19,782.6		19,572.7
Long-term Debt Due Within One Year			2,033.3		1,831.8
Long-term Debt			17,749.3		17,740.9
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances	[2]		530.8
Retirements and Principal Payments			322.4	$ 238.8
Short-term Debt:
Securitized Debt for Receivables	[3]		719.0		675.0
Commercial Paper			502.0		125.0
Total Short-term Debt			$ 1,221.0		$ 800.0
Securitized Debt for Receivables	[3],[4]		0.58%		0.30%
Comparative Accounts Receivable Information
Effective Interest Rates on Securitization of Accounts Receivable			0.58%	0.26%
Net Uncollectible Accounts Receivable Written Off			$ 5.7	$ 6.6
Customer Accounts Receivable Managed Portfolio
Accounts Receivable Retained Interest and Pledged as Collateral Less Uncollectible Accounts			849.8		$ 924.8
Total Principal Outstanding			719.0		675.0
Delinquent Securitized Accounts Receivable			52.1		48.3
Bad Debt Reserves Related to Securitization of Accounts Receivable			20.9		17.5
Unbilled Receivables Related to Securitization of Accounts Receivable			264.0		357.8
Financing Activities (Textuals) [Abstract]
Trust Fund Assets One Time Fee Obligation for Nuclear Fuel Disposition			309.0		$ 309.0
Repayments of Long-term Debt			322.4	238.8
Issuance of Long-term Debt	[2]		530.8
Reacquired Pollution Controls Bonds Held by Trustees			$ 554.0
Maximum Percentage Debt to Capitalization			67.50%
Total Commitment from Bank Conduits to Finance Receivables			$ 750.0
Commercial Paper [Member]
Short-term Debt:
Weighted Average Interest Rate	[4]		0.77%		0.81%
AEP Subsidiaries [Member]
Long-term Debt
Long-term Debt Due Within One Year			$ 361.0		$ 410.4
Long-term Debt			1,835.3		1,971.4
AEP Subsidiaries [Member] | Notes Payable [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 1.0
Interest Rate (Variable)			Variable
Due Date			2017
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 1.0
Due Date			2017
AEP Generating Co [Member] | Senior Unsecured Notes [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 3.7
Interest Rate (Percentage)			6.33%
Due Date			2037
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 3.7
Due Date			2037
Appalachian Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 3,919.3		3,930.7
Long-term Debt Due Within One Year			318.3		318.0
Long-term Debt			3,601.0		3,612.7
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			136.5	11.0
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			136.6		135.4
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			1.8	2.5
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			384.4	429.6
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 136.5	$ 11.0
Maximum Percentage Debt to Capitalization			67.50%
Appalachian Power Co [Member] | Utility [Member]
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits [Abstract]
Maximum Borrowings from Money Pool			$ 286.9
Maximum Loans to Money Pool			25.7
Average Borrowings from Money Pool			183.2
Average Loans to Money Pool			25.5
Net Loans (Borrowings) to/from Utility Money Pool			(146.4)
Authorized Short Term Borrowing Limit			$ 600.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			0.83%	0.59%
Minimum Interest Rate			0.69%	0.39%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			0.73%	0.00%
Average Interest Rate For Funds Loaned			0.73%	0.45%
Appalachian Power Co [Member] | Pollution Control Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances	[2]		$ 125.3
Retirements and Principal Payments			$ 125.3
Interest Rate (Variable)			Variable
Due Date			2016
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 125.3
Issuance of Long-term Debt	[2]		$ 125.3
Due Date			2016
Appalachian Power Co [Member] | Securitization Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 11.2
Interest Rate (Percentage)			2.008%
Due Date			2024
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 11.2
Due Date			2024
Indiana Michigan Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 2,366.6		2,000.0
Long-term Debt Due Within One Year			151.5		162.9
Long-term Debt			2,215.1		1,837.1
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			28.8	$ 25.9
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			125.3		134.8
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			1.9	2.4
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			388.1	419.6
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			28.8	$ 25.9
Reacquired Pollution Controls Bonds Held by Trustees			$ 40.0
Maximum Percentage Debt to Capitalization			67.50%
Indiana Michigan Power Co [Member] | Utility [Member]
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits [Abstract]
Maximum Borrowings from Money Pool			$ 369.1
Maximum Loans to Money Pool			62.5
Average Borrowings from Money Pool			267.3
Average Loans to Money Pool			17.0
Net Loans (Borrowings) to/from Utility Money Pool			2.8
Authorized Short Term Borrowing Limit			$ 500.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			0.83%	0.59%
Minimum Interest Rate			0.69%	0.39%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			0.72%	0.46%
Average Interest Rate For Funds Loaned			0.74%	0.46%
Indiana Michigan Power Co [Member] | Notes Payable Two [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 0.3
Interest Rate (Variable)			0.0212
Due Date			2016
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 0.3
Due Date			2016
Indiana Michigan Power Co [Member] | Notes Payable Three [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 6.9
Interest Rate (Variable)			Variable
Due Date			2017
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 6.9
Due Date			2017
Indiana Michigan Power Co [Member] | Notes Payable Four [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 10.2
Interest Rate (Variable)			Variable
Due Date			2019
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 10.2
Due Date			2019
Indiana Michigan Power Co [Member] | Notes Payable Five [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 10.7
Interest Rate (Variable)			Variable
Due Date			2019
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 10.7
Due Date			2019
Indiana Michigan Power Co [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 0.3
Interest Rate (Percentage)			6.00%
Due Date			2025
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 0.3
Due Date			2025
Indiana Michigan Power Co [Member] | Senior Unsecured Notes [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances	[2]		$ 400.0
Interest Rate (Percentage)			4.55%
Due Date			2046
Financing Activities (Textuals) [Abstract]
Issuance of Long-term Debt	[2]		$ 400.0
Due Date			2046
Indiana Michigan Power Co [Member] | Notes Payable [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 0.4
Interest Rate (Variable)			Variable
Due Date			2016
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 0.4
Due Date			2016
Indiana Michigan Power Co [Member] | Notes Payable [Member] | Subsequent Event [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments		$ 13.0
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt		13.0
Ohio Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 2,135.5		2,157.7
Long-term Debt Due Within One Year			395.6		395.9
Long-term Debt			1,739.9		1,761.8
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			22.8	$ 22.2
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			339.0		351.4
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			7.9	8.0
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			646.6	715.0
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			22.8	$ 22.2
Reacquired Pollution Controls Bonds Held by Trustees			345.0
Ohio Power Co [Member] | Utility [Member]
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits [Abstract]
Maximum Borrowings from Money Pool			0.0
Maximum Loans to Money Pool			379.2
Average Borrowings from Money Pool			0.0
Average Loans to Money Pool			304.7
Net Loans (Borrowings) to/from Utility Money Pool			221.9
Authorized Short Term Borrowing Limit			$ 400.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			0.83%	0.59%
Minimum Interest Rate			0.69%	0.39%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			0.00%	0.00%
Average Interest Rate For Funds Loaned			0.73%	0.46%
Ohio Power Co [Member] | Securitization Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 22.8
Interest Rate (Percentage)			0.958%
Due Date			2018
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 22.8
Due Date			2018
Public Service Co Of Oklahoma [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 1,286.3		1,286.1
Long-term Debt Due Within One Year			275.4		275.4
Long-term Debt			1,010.9		1,010.7
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			0.1	$ 0.1
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			94.5		116.1
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			1.4	1.4
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			272.1	302.5
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 0.1	$ 0.1
Maximum Percentage Debt to Capitalization			67.50%
Public Service Co Of Oklahoma [Member] | Utility [Member]
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits [Abstract]
Maximum Borrowings from Money Pool			$ 0.0
Maximum Loans to Money Pool			91.0
Average Borrowings from Money Pool			0.0
Average Loans to Money Pool			48.7
Net Loans (Borrowings) to/from Utility Money Pool			8.4
Authorized Short Term Borrowing Limit			$ 300.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			0.83%	0.59%
Minimum Interest Rate			0.69%	0.39%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			0.00%	0.49%
Average Interest Rate For Funds Loaned			0.72%	0.44%
Public Service Co Of Oklahoma [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 0.1
Interest Rate (Percentage)			3.00%
Due Date			2027
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 0.1
Due Date			2027
Southwestern Electric Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 2,272.4		2,273.5
Long-term Debt Due Within One Year			253.3		3.3
Long-term Debt			2,019.1		2,270.2
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			1.6	$ 55.1
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			121.2		$ 151.8
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			1.5	1.7
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			336.1	373.2
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 1.6	$ 55.1
Maximum Percentage Debt to Capitalization			67.50%
Southwestern Electric Power Co [Member] | Utility [Member]
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits [Abstract]
Maximum Borrowings from Money Pool			$ 221.8
Maximum Loans to Money Pool			0.0
Average Borrowings from Money Pool			148.0
Average Loans to Money Pool			0.0
Net Loans (Borrowings) to/from Utility Money Pool			(217.8)
Authorized Short Term Borrowing Limit			$ 350.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			0.83%	0.59%
Minimum Interest Rate			0.69%	0.39%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			0.73%	0.46%
Average Interest Rate For Funds Loaned			0.00%	0.52%
Southwestern Electric Power Co [Member] | Nonutility [Member]
Money Pool Participants Money Pool Activity And Authorized Borrowing Limits [Abstract]
Maximum Loans to Money Pool			$ 2.0
Average Loans to Money Pool			2.0
Net Loans (Borrowings) to/from Utility Money Pool			$ 2.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			0.83%
Minimum Interest Rate			0.69%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Loaned			0.73%
Southwestern Electric Power Co [Member] | Notes Payable [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 1.6
Interest Rate (Percentage)			4.58%
Due Date			2032
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 1.6
Due Date			2032
AEP Texas Central Co [Member] | Securitization Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 44.2
Interest Rate (Percentage)			6.25%
Due Date			2016
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 44.2
Due Date			2016
AEP Texas Central Co [Member] | Securitization Bonds Two [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 83.7
Interest Rate (Percentage)			5.17%
Due Date			2018
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 83.7
Due Date			2018
Transource Missouri [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances	[2]		$ 5.5
Interest Rate (Variable)			Variable
Due Date			2018
Financing Activities (Textuals) [Abstract]
Issuance of Long-term Debt	[2]		$ 5.5
Due Date			2018
Transource Missouri [Member] | Other Long Term Debt [Member] | Subsequent Event [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances		$ 6.0
Due Date		2018
Financing Activities (Textuals) [Abstract]
Issuance of Long-term Debt		$ 6.0
Due Date		2018

[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 spent nuclear fuel 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 $309 million and $309 million as of March 31, 2016 and December 31, 2015, respectively, and are included in Spent Nuclear Fuel and Decommissioning Trusts on the condensed balance sheets.

[2] 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.

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

[4] Weighted average rate.