RATE MATTERS - KPCo Rate Matters (Details) - USD ($) $ in Millions	1 Months Ended									9 Months Ended
	Oct. 29, 2025	Aug. 31, 2025	Jun. 30, 2025	Mar. 31, 2025	Jan. 31, 2025	Feb. 29, 2024	Jan. 31, 2024	Nov. 30, 2023	Jun. 30, 2023	Sep. 30, 2025	Jul. 31, 2021
Public Utilities, General Disclosures [Line Items]
Total Issuances										$ 6,300.0
KPCo
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)		$ 96.0
Requested return on equity		10.00%
Requested debt capital structure		53.90%
Requested equity capital structure		46.10%
Increase in PJM transmission costs		$ 10.0
Increase due to load loss		9.0
Requested rate increase related to depreciation rates		6.0
KPCo | Securitization Bonds
Public Utilities, General Disclosures [Line Items]
Total Issuances										$ 477.7
KPCo | Mitchell Plant
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)		$ 20.0
Jointly owned utility plant, percentage of ownership share										50.00%
Proportionate energy and capacity share			50.00%
Net Book Value										$ 529.0
KPCo | Mitchell Plant ELG investments
Public Utilities, General Disclosures [Line Items]
Jointly owned utility plant, percentage of ownership share											50.00%
Estimated cost to be recovered			$ 78.0
KPCo | Mitchell Plant Non-ELG Capital Investments
Public Utilities, General Disclosures [Line Items]
Estimated cost to be recovered			$ 60.0
WPCo | Mitchell Plant
Public Utilities, General Disclosures [Line Items]
Jointly owned utility plant, percentage of ownership share										50.00%
WPCo | Mitchell Plant ELG investments
Public Utilities, General Disclosures [Line Items]
Proportionate ownership share requested to be transferred			50.00%
WPCo | Mitchell Plant Non-ELG Capital Investments
Public Utilities, General Disclosures [Line Items]
Jointly owned utility plant, percentage of ownership share											50.00%
Proportionate ownership share requested to be transferred			50.00%
WPCo | Mitchell Plant ELG investments
Public Utilities, General Disclosures [Line Items]
Subsidiary, ownership percentage, parent											100.00%
2023 Kentucky Base Rate and Securitization Case | KPCo
Public Utilities, General Disclosures [Line Items]
Requested annual base rate increase (decrease)									$ 94.0
Requested return on equity									9.90%
Requested securitization bonds regulatory assets recovery									$ 471.0
Settlement agreement annual increase								$ 75.0
Settlement agreement return on common equity								9.75%
Settlement agreement securitization bonds regulatory assets recovery								$ 471.0
Approved net increase in Kentucky annual revenues							$ 60.0
Approved return on equity							9.75%
Reduction in revenue requirement for recovery of actual test year pjm transmission costs					$ 14.0	$ 14.0	$ 14.0
Order entered in mandated period					30 days
Request to defer transmission costs, amount denied				$ 16.0
Regulatory assets expected to be recovered through securitization			$ 500.0
2023 Kentucky Base Rate and Securitization Case | KPCo | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Recovery of costs, approved	$ 16.0
Recovery of costs, period	22 months
2023 Kentucky Base Rate and Securitization Case | KPCo | Securitization Bonds
Public Utilities, General Disclosures [Line Items]
Total Issuances			478.0
Non-utility issuance costs			6.0
Securitized offset for net present value of return on ADIT			29.0
2023 Kentucky Base Rate and Securitization Case | KPCo | Plant Retirement Costs – Asset Retirement Obligation Costs
Public Utilities, General Disclosures [Line Items]
Regulatory assets expected to be recovered through securitization			311.0
2023 Kentucky Base Rate and Securitization Case | KPCo | Storm-Related Costs
Public Utilities, General Disclosures [Line Items]
Regulatory assets expected to be recovered through securitization			79.0
2023 Kentucky Base Rate and Securitization Case | KPCo | Under-Recovered Purchased Power Rider Costs
Public Utilities, General Disclosures [Line Items]
Regulatory assets expected to be recovered through securitization			56.0
2023 Kentucky Base Rate and Securitization Case | KPCo | Deferred Purchased Power Expenses
Public Utilities, General Disclosures [Line Items]
Regulatory assets expected to be recovered through securitization			51.0
2023 Kentucky Base Rate and Securitization Case | KPCo | Issuance Expenses
Public Utilities, General Disclosures [Line Items]
Regulatory assets expected to be recovered through securitization			$ 3.0
2023 Kentucky Base Rate and Securitization Case | KPCo | Mitchell Plant
Public Utilities, General Disclosures [Line Items]
Jointly owned utility plant, percentage of ownership share									50.00%