Financing Activities (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended
		Apr. 27, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Long-term Debt
Senior Unsecured Notes			$ 14,360.2		$ 14,761.0
Pollution Control Bonds			1,620.8		1,725.1
Notes Payable			293.2		326.9
Securitization Bonds			1,582.1		1,705.0
Spent Nuclear Fuel Obligation	[1]		266.6		266.3
Other Long-term Debt			1,113.5		1,606.9
Total Long-term Debt Outstanding			19,236.4		20,256.4
Long-term Debt Due Within One Year			2,514.2		2,878.0
Long-term Debt			16,722.2		17,378.4
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances	[2]		84.0
Retirements and Principal Payments			1,242.3	$ 322.4
Short-term Debt:
Securitized Debt for Receivables	[3]		572.0		673.0
Commercial Paper			964.0		1,040.0
Total Short-term Debt			$ 1,536.0		$ 1,713.0
Securitized Debt for Receivables	[3],[4]		1.00%		0.70%
Comparative Accounts Receivable Information
Effective Interest Rates on Securitization of Accounts Receivable			1.00%	0.58%
Net Uncollectible Accounts Receivable Written Off			$ 5.9	$ 5.7
Customer Accounts Receivable Managed Portfolio
Accounts Receivable Retained Interest and Pledged as Collateral Less Uncollectible Accounts			872.6		$ 945.0
Total Principal Outstanding			572.0		673.0
Delinquent Securitized Accounts Receivable			49.0		42.7
Bad Debt Reserves Related to Securitization of Accounts Receivable			27.5		27.7
Unbilled Receivables Related to Securitization of Accounts Receivable			253.6		322.1
Financing Activities (Textuals) [Abstract]
Trust Fund Assets One Time Fee Obligation for Nuclear Fuel Disposition			310.0		311.0
Repayments of Long-term Debt			1,242.3	322.4
Issuance of Long-term Debt	[2]		84.0
Reacquired Pollution Controls Bonds Held by Trustees			718.0
Total Commitment from Bank Conduits to Finance Receivables			750.0
Transource Missouri [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances	[2]		$ 7.0
Interest Rate (Variable)			Variable
Due Date			2018
Financing Activities (Textuals) [Abstract]
Issuance of Long-term Debt	[2]		$ 7.0
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
Retirements and Principal Payments		$ 131.0
Due Date		2018
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt		$ 131.0
Due Date		2018
AEP Generating Co [Member] | Senior Unsecured Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage			6.33%
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 152.7
Due Date			2037
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 152.7
Due Date			2037
Indiana Michigan Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 2,439.5		2,471.4
Long-term Debt Due Within One Year			199.1		209.3
Long-term Debt			2,240.4		2,262.1
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			109.5	28.8
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			134.2		136.7
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			1.5	1.9
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			418.2	388.1
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			109.5	$ 28.8
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			$ 291.9
Maximum Loans to Money Pool			12.5
Average Borrowings from Money Pool			234.9
Average Loans to Money Pool			12.5
Net Loans (Borrowings) to/from Utility Money Pool			274.3
Authorized Short Term Borrowing Limit			$ 500.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			1.27%	0.83%
Minimum Interest Rate			0.92%	0.69%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			1.04%	0.72%
Average Interest Rate For Funds Loaned			1.03%	0.74%
Indiana Michigan Power Co [Member] | Notes Payable [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 1.7
Interest Rate (Variable)			Variable
Due Date			2017
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 1.7
Due Date			2017
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			$ 7.5
Interest Rate (Variable)			Variable
Due Date			2019
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 7.5
Due Date			2019
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			$ 7.9
Interest Rate (Variable)			Variable
Due Date			2019
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 7.9
Due Date			2019
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			$ 8.0
Interest Rate (Variable)			Variable
Due Date			2020
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 8.0
Due Date			2020
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			$ 7.1
Interest Rate (Variable)			Variable
Due Date			2021
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 7.1
Due Date			2021
Indiana Michigan Power Co [Member] | Other Long Term Debt [Member]
Debt Instrument, Interest Rate, Stated Percentage			6.00%
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 0.4
Due Date			2025
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 0.4
Due Date			2025
Indiana Michigan Power Co [Member] | Pollution Control Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances	[2]		$ 25.0
Interest Rate (Variable)			Variable
Due Date			2019
Financing Activities (Textuals) [Abstract]
Issuance of Long-term Debt	[2]		$ 25.0
Due Date			2019
Indiana Michigan Power Co [Member] | Pollution Control Bonds Two [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances	[2]		$ 52.0
Interest Rate (Variable)			Variable
Due Date			2021
Financing Activities (Textuals) [Abstract]
Issuance of Long-term Debt	[2]		$ 52.0
Due Date			2021
Indiana Michigan Power Co [Member] | Pollution Control Bonds Three [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 52.0
Interest Rate (Variable)			Variable
Due Date			2017
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 52.0
Due Date			2017
Indiana Michigan Power Co [Member] | Pollution Control Bonds Four [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 25.0
Interest Rate (Variable)			Variable
Due Date			2017
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 25.0
Due Date			2017
Appalachian Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 3,918.8		4,033.9
Long-term Debt Due Within One Year			399.0		503.1
Long-term Debt			3,519.8		3,530.8
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			115.9	$ 136.5
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			131.4		142.0
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			1.4	1.8
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			369.7	384.4
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			115.9	$ 136.5
Reacquired Pollution Controls Bonds Held by Trustees			$ 104.0
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			$ 231.3
Maximum Loans to Money Pool			24.1
Average Borrowings from Money Pool			177.7
Average Loans to Money Pool			23.9
Net Loans (Borrowings) to/from Utility Money Pool			158.7
Authorized Short Term Borrowing Limit			$ 600.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			1.27%	0.83%
Minimum Interest Rate			0.92%	0.69%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			1.04%	0.73%
Average Interest Rate For Funds Loaned			1.03%	0.73%
Appalachian Power Co [Member] | Pollution Control Bonds [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 104.4
Interest Rate (Variable)			Variable
Due Date			2017
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 104.4
Due Date			2017
Appalachian Power Co [Member] | Securitization Bonds [Member]
Debt Instrument, Interest Rate, Stated Percentage			2.008%
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 11.5
Due Date			2024
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 11.5
Due Date			2024
Ohio Power Co [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 1,742.0		1,763.9
Long-term Debt Due Within One Year			46.8		46.4
Long-term Debt			1,695.2		1,717.5
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			22.5	$ 22.8
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			367.6		388.3
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			5.7	7.9
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			632.3	646.6
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			22.5	$ 22.8
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			84.0
Maximum Loans to Money Pool			56.2
Average Borrowings from Money Pool			35.4
Average Loans to Money Pool			27.9
Net Loans (Borrowings) to/from Utility Money Pool			18.3
Authorized Short Term Borrowing Limit			$ 400.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			1.27%	0.83%
Minimum Interest Rate			0.92%	0.69%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			1.10%	0.00%
Average Interest Rate For Funds Loaned			0.98%	0.73%
Ohio Power Co [Member] | Securitization Bonds [Member]
Debt Instrument, Interest Rate, Stated Percentage			0.958%
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 22.4
Due Date			2018
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 22.4
Due Date			2018
Public Service Co Of Oklahoma [Member]
Long-term Debt
Total Long-term Debt Outstanding			$ 1,286.1		1,286.0
Long-term Debt Due Within One Year			0.5		0.5
Long-term Debt			1,285.6		1,285.5
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			99.4		110.4
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			1.5	1.4
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			286.8	272.1
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			$ 163.7
Maximum Loans to Money Pool			0.0
Average Borrowings from Money Pool			91.8
Average Loans to Money Pool			0.0
Net Loans (Borrowings) to/from Utility Money Pool			163.7
Authorized Short Term Borrowing Limit			$ 300.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			1.27%	0.83%
Minimum Interest Rate			0.92%	0.69%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			1.06%	0.00%
Average Interest Rate For Funds Loaned			0.00%	0.72%
Public Service Co Of Oklahoma [Member] | Other Long Term Debt [Member]
Debt Instrument, Interest Rate, Stated Percentage			3.00%
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 0.1
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			$ 2,427.7		2,679.1
Long-term Debt Due Within One Year			485.4		353.7
Long-term Debt			1,942.3		2,325.4
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			251.7	$ 1.6
Accounts Receivable and Accrued Unbilled Revenues
Accounts Receivable and Accrued Unbilled Revenues			107.8		130.9
Fees Paid to AEP Credit for Customer Accounts Receivable Sold
Fees Paid to AEP Credit for Customer Accounts Receivable Sold			1.6	1.5
Proceeds from Sale of Receivables
Proceeds from Sale of Receivables to AEP Credit			341.2	336.1
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 251.7	$ 1.6
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			$ 187.5
Maximum Loans to Money Pool			178.6
Average Borrowings from Money Pool			139.5
Average Loans to Money Pool			169.5
Net Loans (Borrowings) to/from Utility Money Pool			167.9
Authorized Short Term Borrowing Limit			$ 350.0
Maximum and Minimum Interest Rates [Abstract]
Maximum Interest Rate			1.27%	0.83%
Minimum Interest Rate			0.92%	0.69%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Borrowed			1.06%	0.73%
Average Interest Rate For Funds Loaned			0.98%	0.00%
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			1.27%
Minimum Interest Rate			0.92%
Average Interest Rates for Funds Borrowed From and Loaned to Money Pool [Abstract]
Average Interest Rate For Funds Loaned			1.03%
Southwestern Electric Power Co [Member] | Notes Payable [Member]
Debt Instrument, Interest Rate, Stated Percentage			4.58%
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 1.6
Due Date			2032
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 1.6
Due Date			2032
Southwestern Electric Power Co [Member] | Other Long Term Debt [Member]
Debt Instrument, Interest Rate, Stated Percentage			3.50%
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 0.1
Due Date			2023
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 0.1
Due Date			2023
Southwestern Electric Power Co [Member] | Senior Unsecured Notes [Member]
Debt Instrument, Interest Rate, Stated Percentage			5.55%
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 250.0
Due Date			2017
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 250.0
Due Date			2017
AEP Texas Central Co [Member] | Securitization Bonds [Member]
Debt Instrument, Interest Rate, Stated Percentage			5.17%
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 89.9
Due Date			2018
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 89.9
Due Date			2018
Transource Energy [Member] | Other Long Term Debt [Member] | Subsequent Event [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Issuances	[2]	$ 132.0
Due Date		2020
Financing Activities (Textuals) [Abstract]
Issuance of Long-term Debt	[2]	$ 132.0
Due Date		2020
AEP Generation Resources [Member] | Other Long Term Debt [Member]
Long-term Debt and Other Securities Issued, Retired and Principal Payments Made
Retirements and Principal Payments			$ 500.0
Interest Rate (Variable)			Variable
Due Date			2017
Financing Activities (Textuals) [Abstract]
Repayments of Long-term Debt			$ 500.0
Due Date			2017
Includes Debt Included In Liabilities Held For Sale [Member]
Long-term Debt
Total Long-term Debt Outstanding	[5]				20,391.2
Long-term Debt Due Within One Year					3,013.4
Long-term Debt					$ 17,377.8
Commercial Paper [Member]
Short-term Debt:
Weighted Average Interest Rate	[4]		1.27%		1.02%

[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 $310 million and $311 million as of March 31, 2017 and December 31, 2016, respectively, and are included in Spent Nuclear Fuel and Decommissioning Trusts on the 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.

[5] Amount includes debt related to the Lawrenceburg Plant that has been classified as Liabilities Held for Sale on the balance sheet and has a fair value of $172 million. See the Assets and Liabilities Held for Sale section of Note 6 for additional information.