Acquisitions and Dispositions (Details)		3 Months Ended				9 Months Ended
		Sep. 30, 2022 USD ($) MW	Jun. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Sep. 30, 2022 USD ($) MW	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Obligations Under Operating Leases		$ 540,000,000.0				$ 540,000,000.0		$ 492,800,000
Asset Retirement Obligation, Liabilities Settled	[1],[2],[3],[4],[5]					29,400,000
Additional Paid in Capital		8,001,000,000				8,001,000,000		7,172,600,000
Property, Plant and Equipment		24,590,700,000				24,590,700,000		23,088,100,000
Noncontrolling Interests		234,100,000				234,100,000		247,000,000.0
Customers		885,600,000				885,600,000		720,900,000
Materials and Supplies		801,900,000				801,900,000		681,300,000
Property, Plant and Equipment, Net		69,813,100,000				69,813,100,000		66,001,300,000
Regulatory Assets, Noncurrent		3,877,500,000				3,877,500,000		4,142,300,000
Assets Held for Sale		2,830,600,000				2,830,600,000		2,919,700,000
Accounts Payable, Current		2,240,200,000				2,240,200,000		2,054,600,000
Long-term Debt Due Within One Year	[6]	1,403,500,000				1,403,500,000		2,153,800,000
Customer Deposits, Current		375,500,000				375,500,000		321,600,000
Long-term Debt	[7]	33,646,600,000				33,646,600,000		31,300,700,000
Regulatory Liabilities and Deferred Investment Tax Credits		7,934,100,000				7,934,100,000		8,686,300,000
Liabilities Held for Sale		1,992,000,000				1,992,000,000		1,880,900,000
Proceeds from Sale of Property, Plant, and Equipment						215,700,000	$ 17,400,000
Gain (Loss) on Disposition of Assets		$ 0		$ 0		(116,300,000)	0
Proceeds of Mineral Rights Sale
Proceeds from Sale of Property, Plant, and Equipment						120,000,000
Gain (Loss) on Disposition of Other Assets						$ 116,000,000
BP Wind Energy
Wind Generation MWs | MW						724
Equity Method Investment, Ownership Percentage		50.00%				50.00%
Impairment of Equity Method Investment		$ 2,000,000	$ 186,000,000			$ 188,000,000
Dry Lake Solar Project
Payments to Acquire Property, Plant, and Equipment						0	114,400,000
North Central Wind Energy Facilities
Payments to Acquire Property, Plant, and Equipment						$ 1,207,300,000	652,800,000
Mitchell Power Plant
Approximate OVEC Generating Capacity (MWs) | MW		1,560				1,560
NBV Mitchell Including CWIP and Inventory		$ 576,000,000				$ 576,000,000
Dry Lake Solar Project
Percentage of an Asset Acquired		75.00%				75.00%
Noncash or Part Noncash Acquisition, Other Assets Acquired					$ 18,900,000
Dry Lake Solar Project | Noncontrolling Interest [Member]
Noncash or Part Noncash Acquisition, Other Assets Acquired					$ 18,900,000
North Central Wind Energy Facilities
Payments to Acquire Property, Plant, and Equipment						$ 2,000,000,000
Transmission Operations [Member]
Enterprise Value		$ 2,850,000,000				2,850,000,000
Transmission Operations [Member] | Proceeds for KY Operations
Enterprise Value		2,646,000,000				2,646,000,000
Transmission Operations [Member] | Kentucky Transmission Company
Customers		1,700,000				1,700,000		1,500,000
Materials and Supplies		0				0		0
Property, Plant and Equipment, Net		167,000,000.0				167,000,000.0		165,300,000
Regulatory Assets, Noncurrent		0				0		0
Disposal Group, Including Discontinued Operation, Other Assets		5,000,000.0				5,000,000.0		1,100,000
Disposal Group, Including Discontinued Operation, Assets		173,700,000				173,700,000		167,900,000
Assets Held for Sale		173,700,000				173,700,000		167,900,000
Accounts Payable, Current		700,000				700,000		1,100,000
Long-term Debt Due Within One Year		0				0		0
Customer Deposits, Current		0				0		0
Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities		16,400,000				16,400,000		15,400,000
Long-term Debt		0				0		0
Regulatory Liabilities and Deferred Investment Tax Credits		8,000,000.0				8,000,000.0		7,600,000
Disposal Group, Including Discontinued Operation, Other Liabilities, Current		2,500,000				2,500,000		3,500,000
Liabilities Held for Sale		$ 27,600,000				$ 27,600,000		27,600,000
Gain (Loss) on Disposition of Business				0
Generation And Marketing [Member]
Coal Generation MWs | MW		595				595
Generation And Marketing [Member] | Dry Lake Solar Project
Payments to Acquire Property, Plant, and Equipment						$ 114,000,000
Generation And Marketing [Member] | Dry Lake Solar Project | Payment at Closing
Payments to Acquire Property, Plant, and Equipment						103,000,000
Generation And Marketing [Member] | Dry Lake Solar Project | Payment When Put in Service
Payments to Acquire Property, Plant, and Equipment						11,000,000
Generation And Marketing [Member] | Dry Lake Solar Project
Property, Plant and Equipment		$ 143,000,000				143,000,000
Noncontrolling Interests		34,000,000				$ 34,000,000
Solar Generation MWs | MW						100
Generation And Marketing [Member] | Dry Lake Solar Project | Noncontrolling Interest [Member]
Noncash or Part Noncash Acquisition, Other Assets Acquired						$ 16,000,000
Vertically Integrated Utilities [Member]
Enterprise Value		2,850,000,000				2,850,000,000
Vertically Integrated Utilities [Member] | Proceeds for KY Operations
Enterprise Value		2,646,000,000				2,646,000,000
Vertically Integrated Utilities [Member] | Kentucky Power Company and Kentucky Transmission Company
Customers		77,800,000				77,800,000		33,200,000
Materials and Supplies		36,700,000				36,700,000		30,600,000
Property, Plant and Equipment, Net		2,387,400,000				2,387,400,000		2,302,700,000
Regulatory Assets, Noncurrent		508,600,000				508,600,000		484,700,000
Disposal Group, Including Discontinued Operation, Other Assets		38,100,000				38,100,000		68,500,000
Disposal Group, Including Discontinued Operation, Assets		3,048,600,000				3,048,600,000		2,919,700,000
Assets Held for Sale		2,830,600,000				2,830,600,000		2,919,700,000
Accounts Payable, Current		62,400,000				62,400,000		53,400,000
Long-term Debt Due Within One Year		215,000,000.0				215,000,000.0		200,000,000.0
Customer Deposits, Current		38,000,000.0				38,000,000.0		32,400,000
Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities		497,800,000				497,800,000		441,600,000
Long-term Debt		963,400,000				963,400,000		903,100,000
Regulatory Liabilities and Deferred Investment Tax Credits		138,100,000				138,100,000		148,100,000
Disposal Group, Including Discontinued Operation, Other Liabilities, Current		77,300,000				77,300,000		102,300,000
Liabilities Held for Sale		1,992,000,000				1,992,000,000		1,880,900,000
Gain (Loss) on Disposition of Business				$ 0
gain (loss) on Disposition of Business net of Tax		(218,000,000.0)
Deferred Tax Assets, Gross		$ 45,000,000				$ 45,000,000
Vertically Integrated Utilities [Member] | Sundance [Member]
Wind Generation MWs | MW						199
Vertically Integrated Utilities [Member] | Sundance [Member] | North Central Wind Energy Facilities
Payments to Acquire Property, Plant, and Equipment						$ 270,000,000
Vertically Integrated Utilities [Member] | Maverick [Member]
Wind Generation MWs | MW						287
Vertically Integrated Utilities [Member] | Maverick [Member] | North Central Wind Energy Facilities
Payments to Acquire Property, Plant, and Equipment						$ 383,000,000
Vertically Integrated Utilities [Member] | Traverse [Member]
Wind Generation MWs | MW						998
Vertically Integrated Utilities [Member] | Traverse [Member] | North Central Wind Energy Facilities
Payments to Acquire Property, Plant, and Equipment						$ 1,200,000,000
Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities
Wind Generation MWs | MW						1,484
Public Service Co Of Oklahoma [Member]
Percentage of an Asset Acquired		45.50%				45.50%
Obligations Under Operating Leases		$ 100,300,000				$ 100,300,000		62,200,000
Asset Retirement Obligation, Liabilities Settled	[3],[4]					600,000
Additional Paid in Capital		1,042,300,000				1,042,300,000		1,039,000,000
Property, Plant and Equipment		2,386,000,000				2,386,000,000		1,802,400,000
Payments to Acquire Property, Plant, and Equipment						(549,300,000)	(297,000,000.0)
Customers		44,200,000				44,200,000		41,500,000
Materials and Supplies		89,000,000.0				89,000,000.0		56,200,000
Property, Plant and Equipment, Net		5,534,200,000				5,534,200,000		4,802,800,000
Regulatory Assets, Noncurrent		606,200,000				606,200,000		1,037,400,000
Accounts Payable, Current		249,000,000.0				249,000,000.0		157,400,000
Long-term Debt Due Within One Year		500,000				500,000		125,500,000
Customer Deposits, Current		60,500,000				60,500,000		56,200,000
Long-term Debt		1,913,100,000				1,913,100,000		1,788,000,000
Regulatory Liabilities and Deferred Investment Tax Credits		827,900,000				827,900,000		835,300,000
Public Service Co Of Oklahoma [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities
Obligations Under Operating Leases		70,300,000				70,300,000		30,600,000
Property, Plant and Equipment		894,000,000				894,000,000
Public Service Co Of Oklahoma [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities | Sundance [Member]
Obligations Under Operating Leases		12,600,000				12,600,000		12,600,000
Public Service Co Of Oklahoma [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities | Maverick [Member]
Obligations Under Operating Leases		18,000,000.0				18,000,000.0		18,000,000.0
Public Service Co Of Oklahoma [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities | Traverse [Member]
Obligations Under Operating Leases		$ 39,700,000				$ 39,700,000		0
Southwestern Electric Power Co [Member]
Percentage of an Asset Acquired		54.50%				54.50%
Obligations Under Operating Leases		$ 122,500,000				$ 122,500,000		77,700,000
Asset Retirement Obligation, Liabilities Settled	[2],[3],[4]					16,900,000
Additional Paid in Capital		1,445,500,000				1,445,500,000		1,092,200,000
Property, Plant and Equipment		5,454,600,000				5,454,600,000		4,734,500,000
Noncontrolling Interests		400,000				400,000		(100,000)
Payments to Acquire Property, Plant, and Equipment						(658,000,000.0)	$ (355,800,000)
Customers		31,900,000				31,900,000		35,800,000
Materials and Supplies		85,300,000				85,300,000		81,900,000
Property, Plant and Equipment, Net		8,159,900,000				8,159,900,000		7,400,100,000
Regulatory Assets, Noncurrent		992,400,000				992,400,000		1,005,300,000
Accounts Payable, Current		206,200,000				206,200,000		163,600,000
Long-term Debt Due Within One Year		6,200,000				6,200,000		6,200,000
Customer Deposits, Current		65,300,000				65,300,000		62,400,000
Long-term Debt		3,386,200,000				3,386,200,000		3,389,000,000
Regulatory Liabilities and Deferred Investment Tax Credits		818,200,000				818,200,000		806,900,000
Southwestern Electric Power Co [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities
Obligations Under Operating Leases		84,300,000				84,300,000		36,700,000
Property, Plant and Equipment		1,100,000,000				1,100,000,000
Southwestern Electric Power Co [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities | Sundance [Member]
Obligations Under Operating Leases		15,000,000.0				15,000,000.0		15,100,000
Southwestern Electric Power Co [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities | Maverick [Member]
Obligations Under Operating Leases		21,600,000				21,600,000		21,600,000
Southwestern Electric Power Co [Member] | Vertically Integrated Utilities [Member] | North Central Wind Energy Facilities | Traverse [Member]
Obligations Under Operating Leases		$ 47,700,000				$ 47,700,000		0
Kentucky Power Co [Member] | Mitchell Power Plant
Ownership Interest in Mitchell Power Plant		50.00%				50.00%
Kentucky Power Co [Member] | Vertically Integrated Utilities [Member]
Gain (Loss) on Disposition of Business		$ 194,000,000	$ 69,000,000			$ 263,000,000
gain (loss) on Disposition of Business net of Tax		$ 149,000,000				$ 218,000,000
Wheeling Power Company | Mitchell Power Plant
Ownership Interest in Mitchell Power Plant		50.00%				50.00%
AEP Transmission Co [Member]
Obligations Under Operating Leases		$ 1,800,000				$ 1,800,000		1,300,000
Customers		73,800,000				73,800,000		22,500,000
Materials and Supplies		11,700,000				11,700,000		9,300,000
Property, Plant and Equipment, Net		12,742,600,000				12,742,600,000		11,935,700,000
Regulatory Assets, Noncurrent		2,600,000				2,600,000		8,500,000
Assets Held for Sale		173,700,000				173,700,000		167,900,000
Accounts Payable, Current		332,100,000				332,100,000		460,100,000
Long-term Debt Due Within One Year		104,000,000.0				104,000,000.0		104,000,000.0
Long-term Debt		4,782,600,000				4,782,600,000		4,239,900,000
Regulatory Liabilities and Deferred Investment Tax Credits		698,200,000				698,200,000		644,100,000
Liabilities Held for Sale		$ 27,600,000				27,600,000		$ 27,600,000
AEP Transmission Co [Member] | Transmission Operations [Member]
Proceeds from Divestiture of Businesses						$ 1,200,000,000

[1] Includes $18 million and $18 million as of September 30, 2022 and December 31, 2021, respectively, of ARO classified as Liabilities Held for Sale on the balance sheets. See “Disposition of KPCo and KTCo” section of Note 6 for additional information.

[2] Includes ARO related to Sabine and DHLC.

[3] Includes ARO related to asbestos removal.

[4] Includes ARO related to ash disposal facilities.

[5] Includes ARO related to nuclear decommissioning costs for the Cook Plant of $1.98 billion and $1.93 billion as of September 30, 2022 and December 31, 2021, respectively.

[6] Amount excludes $215 million and $200 million as of September 30, 2022 and December 31, 2021, respectively, of Long-term Debt Due Within One Year classified as Liabilities Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 6 for additional information.

[7] Amount excludes $963 million and $903 million as of September 30, 2022 and December 31, 2021, respectively, of Long-term Debt classified as Liabilities Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 6 for additional information.