Acquisitions and Dispositions (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) GWh MW	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Accounts Receivable and Accrued Unbilled Revenues		$ 990,800,000		$ 1,145,100,000
Net Property, Plant and Equipment		74,681,400,000		73,339,100,000
Assets Held for Sale		1,382,800,000		0
Accounts Payable, Current		2,433,900,000		2,670,800,000
Liabilities Held for Sale		64,800,000		0
Proceeds from Sale of Property, Plant, and Equipment		1,000,000.0	$ 208,500,000
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
Transmission Operations [Member] | Proceeds for KY Operations
Enterprise Value		2,646,000,000
Generation And Marketing [Member] | 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
Generation And Marketing [Member] | BP Wind Energy
Impairment of Equity Method Investment	$ 186,000,000
Generation And Marketing [Member] | Competitive Contracted Renewable Portfolio
gain (loss) on Disposition of Business net of Tax		(88,500,000)
Accounts Receivable and Accrued Unbilled Revenues		10,000,000.0
Net Property, Plant and Equipment		1,394,000,000
Disposal Group, Including Discontinued Operation, Other Assets		67,300,000
Disposal Group, Including Discontinued Operation, Assets		1,471,300,000
Assets Held for Sale		1,382,800,000
Accounts Payable, Current		4,600,000
Asset Retirement Obligation		31,000,000.0
Operating Lease, Liability		21,600,000
Disposal Group, Including Discontinued Operation, Other Liabilities, Current		7,600,000
Liabilities Held for Sale		64,800,000
Generation And Marketing [Member] | Competitive Contracted Renewables
Enterprise Value		$ 1,500,000,000
Contracted Renewables GWs | GWh		1.4
Competitive Contracted Renewables NBV		$ 1,200,000,000
Equity Method Investment, Ownership Percentage		50.00%
Equity Method Investments		$ 246,000,000
Proceeds from Sale of Productive Assets		1,200,000,000
Gain (Loss) on Disposition of Business		112,000,000
gain (loss) on Disposition of Business net of Tax		88,000,000
Other Noncontrolling Interests		183,000,000
EQ Method Investments		246,000,000
Deferred Tax Assets, Gross		23,500,000
Vertically Integrated Utilities [Member]
Enterprise Value		2,850,000,000
Pretax Reduction in Investment Basis		335,000,000
Vertically Integrated Utilities [Member] | Proceeds for KY Operations
Enterprise Value		$ 2,646,000,000
Vertically Integrated Utilities [Member] | Sundance [Member]
Wind Generation MWs | MW		199
Vertically Integrated Utilities [Member] | Maverick [Member]
Wind Generation MWs | MW		287
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%
Payments to Acquire Property, Plant, and Equipment		$ 146,000,000
Accounts Receivable and Accrued Unbilled Revenues		80,500,000		70,100,000
Net Property, Plant and Equipment		5,944,300,000		5,626,500,000
Accounts Payable, Current		$ 284,200,000		202,900,000
Southwestern Electric Power Co [Member]
Percentage of an Asset Acquired		54.50%
Payments to Acquire Property, Plant, and Equipment		$ 0	$ (658,000,000.0)
Accounts Receivable and Accrued Unbilled Revenues		38,600,000		38,800,000
Net Property, Plant and Equipment		8,472,900,000		8,262,200,000
Accounts Payable, Current		260,200,000		213,100,000
AEP Transmission Co [Member]
Accounts Receivable and Accrued Unbilled Revenues		91,100,000		46,900,000
Net Property, Plant and Equipment		14,037,700,000		13,339,900,000
Accounts Payable, Current		$ 387,400,000		$ 427,800,000