EFFECTS OF REGULATION - Regulatory Asset - OPCo (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 5,129.2	$ 5,092.4
Pending final regulatory approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	1,310.8	837.3
Approved for recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	3,818.4	4,255.1
Earns/earning a return | Pending final regulatory approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	395.1	349.9
Earns/earning a return | Pending final regulatory approval | Other Regulatory Assets Pending Final Regulatory Approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	20.7	49.8
Earns/earning a return | Pending final regulatory approval | Storm-Related Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	51.0	0.0
Earns/earning a return | Approved for recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	1,711.5	1,946.9
Earns/earning a return | Approved for recovery | Ohio Basic Transmission Cost Rider
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 26.1	42.2
Remaining Recovery Period	2 years
Earns/earning a return | Approved for recovery | Storm-Related Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 106.7	170.9
Remaining Recovery Period	7 years
Earns/earning a return | Approved for recovery | Other Regulatory Assets Approved for Recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 159.9	124.9
Does not earns/earning a return | Pending final regulatory approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	915.7	487.4
Does not earns/earning a return | Pending final regulatory approval | Other Regulatory Assets Pending Final Regulatory Approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	86.3	52.6
Does not earns/earning a return | Pending final regulatory approval | Storm-Related Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	300.8	408.9
Does not earns/earning a return | Approved for recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	2,106.9	2,308.2
Does not earns/earning a return | Approved for recovery | Pension and OPEB Funded Status
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 974.2	1,054.1
Remaining Recovery Period	12 years
Does not earns/earning a return | Approved for recovery | OVEC Purchased Power
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 52.0	50.1
Remaining Recovery Period	2 years
Does not earns/earning a return | Approved for recovery | Unrealized Loss on Forward Commitments
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 53.3	131.4
Remaining Recovery Period	8 years
Does not earns/earning a return | Approved for recovery | Smart Grid Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 33.8	26.3
Remaining Recovery Period	2 years
Does not earns/earning a return | Approved for recovery | Storm-Related Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 66.5	38.5
Remaining Recovery Period	7 years
Does not earns/earning a return | Approved for recovery | Ohio Enhanced Service Reliability Plan
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 26.2	35.3
Remaining Recovery Period	2 years
Does not earns/earning a return | Approved for recovery | Ohio Distribution Investment Rider
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 11.0	35.3
Remaining Recovery Period	2 years
Does not earns/earning a return | Approved for recovery | Other Regulatory Assets Approved for Recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 240.1	269.1
OHIO POWER COMPANY
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	379.1	455.0
OHIO POWER COMPANY | Pending final regulatory approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	0.5	23.6
OHIO POWER COMPANY | Approved for recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	378.6	431.4
OHIO POWER COMPANY | Earns/earning a return | Pending final regulatory approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	0.4	0.0
OHIO POWER COMPANY | Earns/earning a return | Pending final regulatory approval | Other Regulatory Assets Pending Final Regulatory Approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	0.4	0.0
OHIO POWER COMPANY | Earns/earning a return | Approved for recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	26.1	44.0
OHIO POWER COMPANY | Earns/earning a return | Approved for recovery | Ohio Basic Transmission Cost Rider
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 26.1	42.2
Remaining Recovery Period	2 years
OHIO POWER COMPANY | Earns/earning a return | Approved for recovery | Ohio Distribution Decoupling
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 0.0	1.8
OHIO POWER COMPANY | Does not earns/earning a return | Pending final regulatory approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	0.1	23.6
OHIO POWER COMPANY | Does not earns/earning a return | Pending final regulatory approval | Other Regulatory Assets Pending Final Regulatory Approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	0.1	0.0
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	352.5	387.4
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery | Pension and OPEB Funded Status
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 134.0	147.1
Remaining Recovery Period	12 years
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery | OVEC Purchased Power
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 52.0	50.1
Remaining Recovery Period	2 years
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery | Unrealized Loss on Forward Commitments
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 47.6	50.8
Remaining Recovery Period	8 years
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery | Smart Grid Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 33.8	26.3
Remaining Recovery Period	2 years
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery | Storm-Related Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 28.6	30.9
Remaining Recovery Period	2 years
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery | Ohio Enhanced Service Reliability Plan
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 26.2	35.3
Remaining Recovery Period	2 years
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery | Bad Debt Rider
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 13.7	0.7
Remaining Recovery Period	2 years
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery | Ohio Distribution Investment Rider
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 11.0	35.3
Remaining Recovery Period	2 years
OHIO POWER COMPANY | Does not earns/earning a return | Approved for recovery | Other Regulatory Assets Approved for Recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 5.6	$ 10.9