Fair Value Long-term Debt, Other Temporary Investments, Nuclear Trusts (Details) - USD ($)		3 Months Ended		9 Months Ended			12 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022		Sep. 30, 2021	Dec. 31, 2021
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	[1]	$ 35,050,100,000		$ 35,050,100,000			$ 33,454,500,000
Long Term Debt, Fair Value	[2],[3]	30,352,700,000		30,352,700,000			37,564,700,000
Other Temporary Investments
Cost		248,700,000		248,700,000			232,000,000.0
Gross Unrealized Gains		18,600,000		18,600,000			36,400,000
Gross Unrealized Losses		(10,000,000.0)		(10,000,000.0)			0
Other Short-term Investments		257,300,000		257,300,000			268,400,000
Debt and Equity Securities Within Other Temporary Investments
Proceeds from Investment Sales		0	$ 6,000,000.0	15,000,000.0		$ 15,100,000
Purchases of Investments		11,800,000	12,900,000	13,400,000		26,000,000.0
Gross Realized Gains on Investment Sales		0	2,400,000	3,600,000		3,600,000
Gross Realized Losses on Investment Sales		0	0	500,000		0
Nuclear Trust Fund Investments
Fair Value		3,130,500,000		3,130,500,000			3,867,000,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		3,130,500,000		3,130,500,000			3,867,000,000
Fair Value Measurements (Textuals)
Liabilities Held for Sale		1,992,000,000		1,992,000,000			1,880,900,000
Spent Nuclear Fuel and Decommissioning Trusts [Member]
Unrealized Gain on Securities				1,300,000,000			1,900,000,000
Nuclear Trust Fund Investments
Gross Unrealized Gains				1,245,200,000			1,974,700,000
Securities Activity Within Decommissioning and SNF Trusts
Proceeds from Investment Sales		588,500,000	433,900,000	1,818,400,000		1,556,600,000
Purchases of Investments		601,600,000	436,600,000	1,854,800,000		1,586,300,000
Gross Realized Gains on Investment Sales		24,600,000	9,600,000	41,300,000		98,300,000
Gross Realized Losses on Investment Sales		8,400,000	7,000,000.0	33,500,000		12,500,000
Contractual Maturities, Fair Value of Debt Securities
Within 1 year		369,400,000		369,400,000
After 1 year through 5 years		393,800,000		393,800,000
After 5 years through 10 years		229,000,000.0		229,000,000.0
After 10 years		190,900,000		190,900,000
Fair Value Measurements (Textuals)
Adjusted Cost of Debt Securities		1,200,000,000		1,200,000,000			1,200,000,000
Adjusted Cost of Domestic Equity Securities		647,000,000		647,000,000			641,000,000
Unrealized Loss on Securities				14,000,000			4,000,000
Other than Temporary Impairment Losses, Investments				(41,100,000)			(10,100,000)
Cash [Member]
Other Temporary Investments
Cost	[4]	55,100,000		55,100,000			48,000,000.0
Gross Unrealized Gains	[4]	0		0			0
Gross Unrealized Losses	[4]	0		0			0
Other Short-term Investments	[4]	55,100,000		55,100,000			48,000,000.0
Fixed Income Funds [Member]
Nuclear Trust Fund Investments
Fair Value		1,183,100,000		1,183,100,000			1,240,400,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		1,183,100,000		1,183,100,000			1,240,400,000
Fixed Income Funds [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				(33,900,000)			73,400,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				(41,100,000)			(10,100,000)
Mutual Funds Fixed Income [Member]
Other Temporary Investments
Cost	[5]	155,100,000		155,100,000			154,300,000
Gross Unrealized Gains	[5]	0		0			500,000
Gross Unrealized Losses	[5]	(9,700,000)		(9,700,000)			0
Other Short-term Investments	[5]	145,400,000		145,400,000			154,800,000
Domestic [Member]
Nuclear Trust Fund Investments
Fair Value	[6]	1,926,600,000		1,926,600,000			2,541,900,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value	[6]	1,926,600,000		1,926,600,000			2,541,900,000
Domestic [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains	[7]			1,279,100,000			1,901,300,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				0			0
Mutual Funds Equity [Member]
Other Temporary Investments
Cost		20,400,000		20,400,000			19,700,000
Gross Unrealized Gains		18,600,000		18,600,000			35,900,000
Gross Unrealized Losses		(300,000)		(300,000)			0
Other Short-term Investments	[6]	38,700,000		38,700,000			55,600,000
Cash and Cash Equivalents [Member]
Nuclear Trust Fund Investments
Fair Value	[8]	20,800,000		20,800,000			84,700,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value	[8]	20,800,000		20,800,000			84,700,000
Cash and Cash Equivalents [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				0			0
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				0			0
US Government Agencies Debt Securities [Member]
Nuclear Trust Fund Investments
Fair Value		1,115,200,000		1,115,200,000			1,156,400,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		1,115,200,000		1,115,200,000			1,156,400,000
US Government Agencies Debt Securities [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				(26,200,000)			66,300,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				(39,800,000)			(7,900,000)
Corporate Debt [Member]
Nuclear Trust Fund Investments
Fair Value		60,900,000		60,900,000			76,700,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		60,900,000		60,900,000			76,700,000
Corporate Debt [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				(7,700,000)			6,700,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				(1,200,000)			(2,100,000)
State and Local Jurisdiction [Member]
Nuclear Trust Fund Investments
Fair Value		7,000,000.0		7,000,000.0			7,300,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		7,000,000.0		7,000,000.0			7,300,000
State and Local Jurisdiction [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				0			400,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				(100,000)			(100,000)
Other Cash Deposits [Member]
Other Temporary Investments
Cost		18,100,000		18,100,000			10,000,000.0
Gross Unrealized Gains		0		0			0
Gross Unrealized Losses		0		0			0
Other Short-term Investments		18,100,000		18,100,000			10,000,000.0
AEP Texas Inc. [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding		5,693,900,000		5,693,900,000			5,180,800,000
Long Term Debt, Fair Value		4,889,700,000		4,889,700,000			5,663,800,000
AEP Transmission Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding		4,886,600,000		4,886,600,000			4,343,900,000
Long Term Debt, Fair Value		3,926,300,000		3,926,300,000			4,968,200,000
Fair Value Measurements (Textuals)
Liabilities Held for Sale		27,600,000		27,600,000			27,600,000
Appalachian Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding		5,509,800,000		5,509,800,000			4,938,900,000
Long Term Debt, Fair Value		4,994,100,000		4,994,100,000			6,037,100,000
Indiana Michigan Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding		3,206,700,000		3,206,700,000			3,195,000,000
Long Term Debt, Fair Value		2,846,200,000		2,846,200,000			3,748,000,000
Nuclear Trust Fund Investments
Fair Value		3,130,500,000		3,130,500,000			3,867,000,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		3,130,500,000		3,130,500,000			3,867,000,000
Indiana Michigan Power Co [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Unrealized Gain on Securities				1,300,000,000			1,900,000,000
Nuclear Trust Fund Investments
Gross Unrealized Gains				1,245,200,000			1,974,700,000
Securities Activity Within Decommissioning and SNF Trusts
Proceeds from Investment Sales		588,500,000	433,900,000	1,818,400,000		1,556,600,000
Purchases of Investments		601,600,000	436,600,000	1,854,800,000		1,586,300,000
Gross Realized Gains on Investment Sales		24,600,000	9,600,000	41,300,000		98,300,000
Gross Realized Losses on Investment Sales		8,400,000	$ 7,000,000.0	33,500,000		$ 12,500,000
Contractual Maturities, Fair Value of Debt Securities
Within 1 year		369,400,000		369,400,000
After 1 year through 5 years		393,800,000		393,800,000
After 5 years through 10 years		229,000,000.0		229,000,000.0
After 10 years		190,900,000		190,900,000
Fair Value Measurements (Textuals)
Adjusted Cost of Debt Securities		1,200,000,000		1,200,000,000			1,200,000,000
Adjusted Cost of Domestic Equity Securities		647,000,000		647,000,000			641,000,000
Unrealized Loss on Securities				14,000,000			4,000,000
Other than Temporary Impairment Losses, Investments				(41,100,000)			(10,100,000)
Indiana Michigan Power Co [Member] | Fixed Income Funds [Member]
Nuclear Trust Fund Investments
Fair Value		1,183,100,000		1,183,100,000			1,240,400,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		1,183,100,000		1,183,100,000			1,240,400,000
Indiana Michigan Power Co [Member] | Fixed Income Funds [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				(33,900,000)			73,400,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				(41,100,000)			(10,100,000)
Indiana Michigan Power Co [Member] | Domestic [Member]
Nuclear Trust Fund Investments
Fair Value	[6]	1,926,600,000		1,926,600,000			2,541,900,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value	[6]	1,926,600,000		1,926,600,000			2,541,900,000
Indiana Michigan Power Co [Member] | Domestic [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				1,279,100,000	[7]		1,901,300,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				0			0
Indiana Michigan Power Co [Member] | Cash and Cash Equivalents [Member]
Nuclear Trust Fund Investments
Fair Value	[8]	20,800,000		20,800,000			84,700,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value	[8]	20,800,000		20,800,000			84,700,000
Indiana Michigan Power Co [Member] | Cash and Cash Equivalents [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				0			0
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				0			0
Indiana Michigan Power Co [Member] | US Government Agencies Debt Securities [Member]
Nuclear Trust Fund Investments
Fair Value		1,115,200,000		1,115,200,000			1,156,400,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		1,115,200,000		1,115,200,000			1,156,400,000
Indiana Michigan Power Co [Member] | US Government Agencies Debt Securities [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				(26,200,000)			66,300,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				(39,800,000)			(7,900,000)
Indiana Michigan Power Co [Member] | Corporate Debt [Member]
Nuclear Trust Fund Investments
Fair Value		60,900,000		60,900,000			76,700,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		60,900,000		60,900,000			76,700,000
Indiana Michigan Power Co [Member] | Corporate Debt [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				(7,700,000)			6,700,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				(1,200,000)			(2,100,000)
Indiana Michigan Power Co [Member] | State and Local Jurisdiction [Member]
Nuclear Trust Fund Investments
Fair Value		7,000,000.0		7,000,000.0			7,300,000
Contractual Maturities, Fair Value of Debt Securities
Fair Value		7,000,000.0		7,000,000.0			7,300,000
Indiana Michigan Power Co [Member] | State and Local Jurisdiction [Member] | Spent Nuclear Fuel and Decommissioning Trusts [Member]
Nuclear Trust Fund Investments
Gross Unrealized Gains				0			400,000
Fair Value Measurements (Textuals)
Other than Temporary Impairment Losses, Investments				(100,000)			(100,000)
Ohio Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding		2,969,900,000		2,969,900,000			2,968,500,000
Long Term Debt, Fair Value		2,442,000,000		2,442,000,000			3,437,500,000
Public Service Co Of Oklahoma [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding		1,913,600,000		1,913,600,000			1,913,500,000
Long Term Debt, Fair Value		1,616,900,000		1,616,900,000			2,163,700,000
Southwestern Electric Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding		3,392,400,000		3,392,400,000			3,395,200,000
Long Term Debt, Fair Value		2,797,300,000		2,797,300,000			3,792,900,000
Risk Management Commodity Contracts [Member]
Fair Value Measurements (Textuals)
Liabilities Held for Sale							100,000
Equity Units [Member]
Book Values and Fair Values of Long - term Debt
Long Term Debt, Fair Value		842,000,000		842,000,000			1,700,000,000
Held For Sale
Fair Value Measurements (Textuals)
Liabilities Held for Sale		1,200,000,000		1,200,000,000			1,100,000,000
Fair Value Held for Sale [Member]
Fair Value Measurements (Textuals)
Liabilities Held for Sale		$ 1,100,000,000		$ 1,100,000,000			$ 1,200,000,000

[1] The book value amounts exclude Long-term Debt of $1.2 billion and $1.1 billion as of September 30, 2022 and December 31, 2021, respectively, classified as Liabilities Held for Sale on the balance sheets. See “Disposition of KPCo and KTCo” section of Note 6 for additional information.

[2] The fair value amounts exclude Long-term Debt of $1.1 billion and $1.2 billion as of September 30, 2022 and December 31, 2021, respectively, related to KPCo. See “Disposition of KPCo and KTCo” section of Note 6 for additional information.

[3] The fair value amounts include debt related to AEP’s Equity Units and had a fair value of $842 million and $1.7 billion as of September 30, 2022 and December 31, 2021, respectively. See “Equity Units” section of Note 12 for additional information.

[4] Primarily represents amounts held for the repayment of debt.

[5] Primarily short and intermediate maturities which may be sold and do not contain maturity dates.

[6] Amounts represent publicly traded equity securities and equity-based mutual funds.

[7] Amount reported as Gross Unrealized Gains includes unrealized gains of $1.3 billion and $1.9 billion and unrealized losses of $14 million and $4 million as of September 30, 2022 and December 31, 2021, respectively.

[8] Amounts in “Other’’ column primarily represent accrued interest receivables from financial institutions.  Level 1 amounts primarily represent investments in money market funds.