EFFECTS OF REGULATION - Regulatory Asset - APCo (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Regulatory Asset [Line Items]
Total Current Regulatory Assets	$ 445.9	$ 514.0
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 | Under-recovered Fuel Costs
Regulatory Asset [Line Items]
Total Current Regulatory Assets	$ 245.7	357.4
Remaining Recovery Period	1 year
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 | Plant Retirement Costs - Asset Retirement Obligation Costs
Regulatory Asset [Line Items]
Remaining Recovery Period	16 years
Total Noncurrent Regulatory Assets	$ 111.0	110.8
Earns/earning a return | Approved for recovery | Storm-Related Costs
Regulatory Asset [Line Items]
Remaining Recovery Period	7 years
Total Noncurrent Regulatory Assets	$ 106.7	170.9
Earns/earning a return | Approved for recovery | Long-term Under-recovered Fuel Costs - West Virginia
Regulatory Asset [Line Items]
Remaining Recovery Period	10 years
Total Noncurrent Regulatory Assets	$ 283.8	291.5
Earns/earning a return | Approved for recovery | Plant Retirement Costs - Unrecovered Plant
Regulatory Asset [Line Items]
Remaining Recovery Period	22 years
Total Noncurrent Regulatory Assets	$ 661.2	664.2
Earns/earning a return | Approved for recovery | Long-term Under-recovered Fuel Costs - Virginia
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	0.0	107.0
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 | Under-recovered Fuel Costs
Regulatory Asset [Line Items]
Total Current Regulatory Assets	$ 116.0	62.7
Remaining Recovery Period	1 year
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 | Plant Retirement Costs - Asset Retirement Obligation Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	357.4	25.9
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 | Pending final regulatory approval | 2024-2025 Virginia Under-Earnings
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	78.4	0.0
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 | Plant Retirement Costs - Asset Retirement Obligation Costs
Regulatory Asset [Line Items]
Remaining Recovery Period	18 years
Total Noncurrent Regulatory Assets	$ 360.1	330.2
Does not earns/earning a return | Approved for recovery | Storm-Related Costs
Regulatory Asset [Line Items]
Remaining Recovery Period	7 years
Total Noncurrent Regulatory Assets	$ 66.5	38.5
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
Does not earns/earning a return | Approved for recovery | Pension and OPEB Funded Status
Regulatory Asset [Line Items]
Remaining Recovery Period	12 years
Total Noncurrent Regulatory Assets	$ 974.2	1,054.1
Does not earns/earning a return | Approved for recovery | Unamortized Loss on Reacquired Debt
Regulatory Asset [Line Items]
Remaining Recovery Period	24 years
Total Noncurrent Regulatory Assets	$ 90.9	97.2
Does not earns/earning a return | Approved for recovery | 2020-2022 Virginia Triennial Under Earnings
Regulatory Asset [Line Items]
Remaining Recovery Period	3 years
Total Noncurrent Regulatory Assets	$ 26.0	37.4
Does not earns/earning a return | Approved for recovery | Postemployment Benefits
Regulatory Asset [Line Items]
Remaining Recovery Period	3 years
Total Noncurrent Regulatory Assets	$ 27.9	30.6
Does not earns/earning a return | Approved for recovery | Unrealized Loss on Forward Commitments
Regulatory Asset [Line Items]
Remaining Recovery Period	8 years
Total Noncurrent Regulatory Assets	$ 53.3	131.4
APPALACHIAN POWER COMPANY
Regulatory Asset [Line Items]
Total Current Regulatory Assets	148.1	155.4
Total Noncurrent Regulatory Assets	1,366.0	1,155.1
APPALACHIAN POWER COMPANY | Pending final regulatory approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	535.5	125.5
APPALACHIAN POWER COMPANY | Approved for recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	830.5	1,029.6
APPALACHIAN POWER COMPANY | Earns/earning a return | Under-recovered Fuel Costs
Regulatory Asset [Line Items]
Total Current Regulatory Assets	$ 148.1	147.4
Remaining Recovery Period	1 year
APPALACHIAN POWER COMPANY | Earns/earning a return | Pending final regulatory approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 1.1	0.6
APPALACHIAN 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	1.1	0.6
APPALACHIAN POWER COMPANY | Earns/earning a return | Approved for recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 227.3	340.3
APPALACHIAN POWER COMPANY | Earns/earning a return | Approved for recovery | Long-term Under-recovered Fuel Costs - West Virginia
Regulatory Asset [Line Items]
Remaining Recovery Period	10 years
Total Noncurrent Regulatory Assets	$ 154.1	154.2
APPALACHIAN POWER COMPANY | Earns/earning a return | Approved for recovery | Plant Retirement Costs - Unrecovered Plant
Regulatory Asset [Line Items]
Remaining Recovery Period	19 years
Total Noncurrent Regulatory Assets	$ 68.0	72.0
APPALACHIAN POWER COMPANY | Earns/earning a return | Approved for recovery | Long-term Under-recovered Fuel Costs - Virginia
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	0.0	107.0
APPALACHIAN POWER COMPANY | Earns/earning a return | Approved for recovery | Other Regulatory Assets Approved for Recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	5.2	7.1
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Under-recovered Fuel Costs
Regulatory Asset [Line Items]
Total Current Regulatory Assets	$ 0.0	8.0
Remaining Recovery Period	1 year
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Pending final regulatory approval
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 534.4	124.9
APPALACHIAN 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	11.9	7.5
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Pending final regulatory approval | Plant Retirement Costs - Asset Retirement Obligation Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	282.1	25.9
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Pending final regulatory approval | Storm-Related Costs
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	144.2	91.5
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Pending final regulatory approval | 2024-2025 Virginia Under-Earnings
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	78.4	0.0
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Pending final regulatory approval | Pension Settlement
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	17.8	0.0
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 603.2	689.3
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Plant Retirement Costs - Asset Retirement Obligation Costs
Regulatory Asset [Line Items]
Remaining Recovery Period	15 years
Total Noncurrent Regulatory Assets	$ 307.5	324.7
APPALACHIAN 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	$ 30.0	27.8
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Pension and OPEB Funded Status
Regulatory Asset [Line Items]
Remaining Recovery Period	12 years
Total Noncurrent Regulatory Assets	$ 107.9	115.8
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Unamortized Loss on Reacquired Debt
Regulatory Asset [Line Items]
Remaining Recovery Period	21 years
Total Noncurrent Regulatory Assets	$ 67.0	70.7
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | 2020-2022 Virginia Triennial Under Earnings
Regulatory Asset [Line Items]
Remaining Recovery Period	3 years
Total Noncurrent Regulatory Assets	$ 26.0	37.4
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Peak Demand Reduction/Energy Efficiency
Regulatory Asset [Line Items]
Remaining Recovery Period	2 years
Total Noncurrent Regulatory Assets	$ 14.2	15.0
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Postemployment Benefits
Regulatory Asset [Line Items]
Remaining Recovery Period	3 years
Total Noncurrent Regulatory Assets	$ 13.2	14.9
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Vegetation Management Program - West Virginia
Regulatory Asset [Line Items]
Remaining Recovery Period	2 years
Total Noncurrent Regulatory Assets	$ 11.9	12.9
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Virginia Generation Rate Adjustment Clause
Regulatory Asset [Line Items]
Remaining Recovery Period	2 years
Total Noncurrent Regulatory Assets	$ 11.6	10.9
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Excess SO2 Allowance Inventory - Virginia
Regulatory Asset [Line Items]
Remaining Recovery Period	8 years
Total Noncurrent Regulatory Assets	$ 10.5	11.8
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Virginia Transmission Rate Adjustment Clause
Regulatory Asset [Line Items]
Remaining Recovery Period	2 years
Total Noncurrent Regulatory Assets	$ 3.4	25.5
APPALACHIAN POWER COMPANY | Does not earns/earning a return | Approved for recovery | Unrealized Loss on Forward Commitments
Regulatory Asset [Line Items]
Total Noncurrent Regulatory Assets	$ 0.0	$ 21.9