Acquisitions, Development and Divestitures - Development (Details) $ in Millions			3 Months Ended			6 Months Ended
		Nov. 06, 2023 MW	Mar. 31, 2024 USD ($)		Mar. 31, 2023 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2023 USD ($)
Business Acquisition [Line Items]
Transition Service Agreement Cost			$ 48		$ 58
Goodwill			2,247				$ 2,247
Operating Revenues from external customers			2,304		2,415
Net income (loss)			307		285
Indemnification for Safari sale/leaseback			25
Louisville Gas And Electric Co [Member]
Business Acquisition [Line Items]
Goodwill			389				389
Operating Revenues from external customers			476		474
Net income (loss)			93	[1]	86
New NGCC LG&E Planned Ownership Percentage		31.00%
CPCN NGCC Combustion Turbine Facilities Power | MW		640
Kentucky Utilities Co [Member]
Business Acquisition [Line Items]
Goodwill			607				$ 607
Operating Revenues from external customers			525		499
Net income (loss)	[2]		108		88
New NGCC KU Planned Ownership Percentage		69.00%
CPCN NGCC Combustion Turbine Facilities Power | MW		640
Narragansett Electric
Business Acquisition [Line Items]
Total cash consideration						$ 3,800
Rhode Island Regulated
Business Acquisition [Line Items]
Operating Revenues from external customers			549		565
Net income (loss)			64		54
Corporate and Other [Member]
Business Acquisition [Line Items]
Operating Revenues from external customers			1		(1)
Net income (loss)			(96)		(73)
Rhode Island Energy | Rhode Island Energy TSA
Business Acquisition [Line Items]
Other Nonrecurring (Income) Expense			81		54
Rhode Island Energy | Accrual for TSA Markup
Business Acquisition [Line Items]
Other Nonrecurring (Income) Expense			1		$ 2
LGE [Member]
Business Acquisition [Line Items]
CPCN NGCC Combustion Turbine Facilities Power | MW		640
KU [Member]
Business Acquisition [Line Items]
CPCN NGCC Combustion Turbine Facilities Power | MW		640
LKE [Member]
Business Acquisition [Line Items]
ExpectedCapitalCostOfExpansionProject			$ 1,000

[1] Net income equals comprehensive income.

[2] Net income equals comprehensive income.