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Asset Retirement Obligations (Tables)
 12 Months Ended
Dec. 31, 2024
Asset Retirement Obligation Disclosure [Abstract]  
Schedule of Asset Retirement Obligations by Category
The following table presents the AROs recorded on the Consolidated Balance Sheets.
December 31, 2024
DukeDukeDukeDukeDuke
DukeEnergyProgressEnergyEnergyEnergyEnergy
(in millions) EnergyCarolinasEnergyProgressFloridaOhioIndianaPiedmont
Decommissioning of nuclear power facilities
$4,493 $2,050 $2,425 $2,318 $107 $— $— $— 
Closure of ash impoundments5,173 1,867 1,993 1,975 18 72 1,241 — 
Other326 73 130 41 89 67 27 29 
Total asset retirement obligation$9,992 $3,990 $4,548 $4,334 $214 $139 $1,268 $29 
Less: Current portion650 247 231 230 1 8 164 — 
Total noncurrent asset retirement obligation$9,342 $3,743 $4,317 $4,104 $213 $131 $1,104 $29 
Public Utilities General Disclosures
The following table summarizes information about the most recent site-specific nuclear decommissioning cost studies. Decommissioning costs are stated in 2023 or 2024 dollars, depending on the year of the cost study, and include costs to decommission plant components not subject to radioactive contamination.
Decommissioning
(in millions)
Costs
Year of Cost Study
Duke Energy$9,031 
2023 or 2024
Duke Energy Carolinas(a)
4,439 2023
Progress Energy
4,592 2024
Duke Energy Progress(b)
4,477 2024
Duke Energy Florida(c)
115 N/A
(a)    Decommissioning costs for Duke Energy Carolinas reflect its ownership interest in jointly owned reactors. Other joint owners are responsible for decommissioning costs related to their interest in the reactors. Duke Energy Carolinas' site-specific nuclear decommissioning cost study and a funding study were filed with the NCUC and PSCSC in 2024.
(b)    Duke Energy Progress' site-specific nuclear decommissioning cost study was filed with the NCUC and PSCSC in February 2025. An updated funding study will be completed and filed with the NCUC and PSCSC in 2025.
(c)    During 2019, Duke Energy Florida reached an agreement to transfer decommissioning work for Crystal River Unit 3 to a third party and decommissioning costs are based on the agreement with this third party rather than a cost study. Regulatory approval was received from the NRC and the FPSC in April 2020 and August 2020, respectively. Duke Energy Florida provides the FPSC periodic reports on the status and progress of decommissioning activities.
The following table presents the fair value of NDTF assets legally restricted for purposes of settling AROs associated with nuclear decommissioning. Duke Energy Florida entered into an agreement with a third party to decommission Crystal River Unit 3 and was granted an exemption from the NRC, which allows for use of the NDTF for all aspects of nuclear decommissioning. The entire balance of Duke Energy Florida's NDTF may be applied toward license termination, spent fuel and site restoration costs incurred to decommission Crystal River Unit 3 and is excluded from the table below. See Note 17 for additional information related to the fair value of the Duke Energy Registrants' NDTFs.
December 31,
(in millions)20242023
Duke Energy$10,044 $8,851 
Duke Energy Carolinas5,687 5,002 
Progress Energy
4,357 3,849 
Duke Energy Progress4,357 3,849 
The following table includes the current expiration of nuclear operating licenses.
UnitYear of Expiration
Duke Energy Carolinas
Catawba Units 1 and 22043
McGuire Unit 12041
McGuire Unit 22043
Oconee Units 1 and 22033
Oconee Unit 32034
Duke Energy Progress
Brunswick Unit 12036
Brunswick Unit 22034
Harris2046
Robinson2030
Rollforward Schedule of Asset Retirement Obligations
The following tables present changes in the liability associated with AROs.
DukeDukeDukeDukeDuke
DukeEnergyProgressEnergyEnergyEnergyEnergy
(in millions) EnergyCarolinasEnergyProgressFloridaOhioIndianaPiedmont
Balance at December 31, 2022$12,728 $5,382 $6,181 $5,823 $358 $154 $951 $26 
Accretion expense(a)
523 254 237 225 12 7 33 1 
Liabilities settled(b)
(758)(256)(379)(292)(87)(15)(108)— 
Liabilities incurred in the current year29 3 21 6 15 1 4 — 
Revisions in estimates of cash flows(c)
(3,366)(1,370)(1,915)(1,892)(23)(11)(71)(1)
Balance at December 31, 20239,156 4,013 4,145 3,870 275 136 809 26 
Accretion expense(a)
434 183 199 190 9 7 49 2 
Liabilities settled(b)
(634)(212)(321)(232)(89)(7)(94)— 
Liabilities incurred in the current year20 8 12 — 12 — — — 
Revisions in estimates of cash flows(c)
1,016 (2)513 506 7 3 504 1 
Balance at December 31, 2024$9,992 $3,990 $4,548 $4,334 $214 $139 $1,268 $29 
    
(a)    Substantially all accretion expense has been deferred in accordance with regulatory accounting treatment.
(b)    Amounts primarily relate to ash impoundment closures and nuclear decommissioning.
(c)    The amounts recorded represent the discounted cash flows for estimated closure costs as evaluated on a site-by-site basis. The decreases in 2023 primarily relate to lower discounted cash flows for decommissioning the nuclear power facilities due to changes in estimates and economic assumptions including discount rates, cost escalation rates and cash flow timing, as well as lower unit costs associated with ash basin closure, routine maintenance and beneficiation activities, as well as reduction in monitoring wells needed. The increases in 2024 primarily relate to additional scope requirements to regulate the disposal of CCR in landfills and surface impoundments as a result of the 2024 CCR Rule, including an increase in groundwater monitoring wells.