RATE MATTERS - I&M Rate Matters (Details) - INDIANA MICHIGAN POWER COMPANY - USD ($) $ in Thousands	1 Months Ended
	Jul. 30, 2026	Oct. 31, 2025	Jun. 30, 2026	Feb. 28, 2026
Public Utilities, General Disclosures [Line Items]
Earning test, over-earning credit to customers, proposed				$ 53,000
Earning test, over-earning credit to customers, approved			$ 53,000
2024 Michigan Power Supply Cost Recovery \| Subsequent Event \| OVEC ICPA, Cost Disallowance
Public Utilities, General Disclosures [Line Items]
Public utilities, recommended disallowance purchased power	$ 1,000
2024 Michigan Power Supply Cost Recovery \| Subsequent Event \| Rockport UPA, Cost Disallowance
Public Utilities, General Disclosures [Line Items]
Public utilities, recommended disallowance purchased power	$ 0
2024 Michigan Power Supply Cost Recovery \| Minimum
Public Utilities, General Disclosures [Line Items]
Public utilities, recommended disallowance purchased power		$ 259
2024 Michigan Power Supply Cost Recovery \| Maximum
Public Utilities, General Disclosures [Line Items]
Public utilities, recommended disallowance purchased power		$ 14,000