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Property, Plant and Equipment (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation $ 24,597.7 $ 23,088.1  
Property, Plant and Equipment, Transmission 32,312.9 29,911.1  
Property, Plant and Equipment, Distribution 26,077.2 24,440.0  
Property, Plant and Equipment, Other 6,142.1 5,682.9  
Property, Plant and Equipment, Construction Work in Progress 4,664.1 3,684.3  
Accumulated Depreciation 22,511.1 20,805.1  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET [1] 71,282.9 66,001.3  
Assets Held for Sale 2,823.5 2,919.7  
Asset Retirement Obligations (ARO)      
Beginning Balance [2],[3],[4],[5],[6],[7],[8] 2,741.7 2,516.7  
Accretion Expense [2],[3],[4],[5],[6],[7],[8] 111.2 105.0  
Liabilities Incurred [2],[3],[4],[5],[6],[7],[8] 37.4 22.8  
Liabilities Settled [2],[3],[4],[5],[6],[7],[8] (47.0) (41.4)  
Revisions in Cash Flow Estimates [2],[3],[4],[5],[6],[7],[8],[9] 100.3 138.6  
Ending Balance [2],[3],[4],[5],[6],[7],[8] 2,943.6 2,741.7 $ 2,516.7
Asset Retirement Obligations (ARO) Liability for Nuclear Decommissioning of the Cook Plant 2,000.0 1,930.0  
Liabilities Held for Sale 1,955.7 1,880.9  
Allowance for Funds Used During Construction (AFUDC) and Interest Capitalization      
Allowance for Equity Funds Used During Construction 133.7 139.7 148.1
Allowance for Borrowed Funds Used During Construction 63.0 53.8 66.0
Jointly-owned Electric Facilities      
Utility Plant in Service 2,626.0 2,589.4  
Construction Work in Progress 21.5 16.5  
Accumulated Depreciation 1,096.1 947.4  
Asset Impairments and Other Related Charges $ 48.8 11.6 0.0
Property, Plant and Equipment (Textuals)      
Property, Plant and Equipment PROPERTY, PLANT AND EQUIPMENT
The disclosures in this note apply to all Registrants unless indicated otherwise.

Property, Plant and Equipment is shown functionally on the face of the balance sheets. The following tables include the total plant balances as of December 31, 2022 and 2021:
December 31, 2022AEPAEP TexasAEPTCoAPCoI&MOPCoPSOSWEPCo
(in millions)
Regulated Property, Plant and Equipment
Generation
$22,523.1 (a)$— $— $6,776.8 $5,534.6 $— $2,394.8 $5,476.2 (a)
Transmission32,267.8 6,301.5 12,183.2 4,482.8 1,842.2 3,198.6 1,164.4 2,479.8 
Distribution26,077.2 5,312.8 — 4,933.0 3,024.7 6,450.3 3,216.4 2,659.6 
Other5,700.4 1,020.4 451.7 849.2 796.1 1,040.6 466.0 582.6 
CWIP4,630.8 (a)805.2 1,547.1 705.3 253.0 474.3 219.3 369.5 (a)
Less: Accumulated Depreciation
21,947.1 1,759.5 1,012.2 5,397.3 4,117.8 2,564.3 1,839.4 3,314.8 
Total Regulated Property, Plant and Equipment - Net
69,252.2 11,680.4 13,169.8 12,349.8 7,332.8 8,599.5 5,621.5 8,252.9 
Nonregulated Property, Plant and Equipment - Net
2,030.7 1.2 0.3 29.4 78.7 9.8 5.0 9.3 
Total Property, Plant and Equipment - Net
$71,282.9 (b)$11,681.6 $13,170.1 (c)$12,379.2 $7,411.5 $8,609.3 $5,626.5 $8,262.2 
December 31, 2021AEPAEP TexasAEPTCoAPCoI&MOPCoPSOSWEPCo
(in millions)
Regulated Property, Plant and Equipment
Generation
$21,196.8 (a)$— $— $6,683.9 $5,531.8 $— $1,802.4 $4,734.5 (a)
Transmission29,866.0 5,849.9 10,886.3 4,322.4 1,783.1 2,992.8 1,107.7 2,316.9 
Distribution24,440.0 4,917.2 — 4,683.3 2,800.1 6,070.6 3,004.9 2,514.3 
Other5,249.8 958.7 427.2 668.9 755.1 982.2 433.5 542.0 
CWIP3,632.4 (a)551.3 1,394.8 469.9 302.8 365.0 156.0 240.7 (a)
Less: Accumulated Depreciation
20,375.5 1,642.9 772.9 5,047.4 3,885.3 2,457.4 1,707.0 3,002.2 
Total Regulated Property, Plant and Equipment - Net
64,009.5 10,634.2 11,935.4 11,781.0 7,287.6 7,953.2 4,797.5 7,346.2 
Nonregulated Property, Plant and Equipment - Net
1,991.8 1.2 0.3 23.3 23.3 9.8 5.3 53.9 
Total Property, Plant and Equipment - Net
$66,001.3 (b)$10,635.4 $11,935.7 (c)$11,804.3 $7,310.9 $7,963.0 $4,802.8 $7,400.1 

(a)AEP and SWEPCo’s regulated generation and regulated CWIP include amounts related to SWEPCo’s Arkansas jurisdictional share of the Turk Plant.
(b)Amount excludes $2.4 billion and $2.3 billion as of December 31, 2022 and 2021, respectively, of Property, Plant and Equipment - Net classified as Assets Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.
(c)Amount excludes $170 million and $165 million as of December 31, 2022 and 2021, respectively, of Property, Plant and Equipment - Net classified as Assets Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.
Depreciation, Depletion and Amortization

The Registrants provide for depreciation of Property, Plant and Equipment, excluding coal-mining properties, on a straight-line basis over the estimated useful lives of property, generally using composite rates by functional class.  The following tables provide total regulated annual composite depreciation rates and depreciable lives for the Registrants:
AEP
202220212020
Functional Class of PropertyAnnual Composite
Depreciation Rate Ranges
Depreciable
Life Ranges
Annual Composite
Depreciation Rate Ranges
Depreciable
Life Ranges
Annual Composite
Depreciation Rate Ranges
Depreciable
Life Ranges
(in years)(in years)(in years)
Generation2.7%-7.6%20-1322.7%-7.8%20-1322.7%-6.3%20-132
Transmission2.0%-2.7%24-752.0%-2.6%15-752.0%-2.6%15-75
Distribution2.7%-3.6%7-782.8%-3.6%7-802.7%-3.7%7-78
Other3.1%-14.4%5-753.0%-12.5%5-752.8%-11.3%5-75
AEP Texas
202220212020
Functional Class of PropertyAnnual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
(in years)(in years)(in years)
Transmission2.2%50-752.2%50-752.0%50-75
Distribution2.9%7-702.9%7-703.1%7-70
Other6.2%5-505.8%5-506.1%5-50
AEPTCo
202220212020
Functional Class of PropertyAnnual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
(in years)(in years)(in years)
Transmission2.6%24-752.5%24-752.4%24-75
Other6.6%5-566.7%5-566.3%5-64
APCo
202220212020
Functional Class of PropertyAnnual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
(in years)(in years)(in years)
Generation3.6%35-1183.6%35-1183.3%35-118
Transmission2.2%24-752.1%15-752.2%15-75
Distribution3.6%12-573.5%12-573.7%12-57
Other7.3%5-558.5%5-557.8%5-55
I&M
202220212020
Functional Class of PropertyAnnual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
(in years)(in years)(in years)
Generation4.9%20-1324.7%20-1324.6%20-132
Transmission2.5%44-672.4%45-702.3%45-70
Distribution3.1%14-713.4%14-713.4%14-71
Other10.1%5-459.0%5-5110.2%5-51
OPCo
202220212020
Functional Class of PropertyAnnual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
(in years)(in years)(in years)
Transmission2.3%39-602.3%39-602.3%39-60
Distribution2.7%11-702.9%11-703.1%14-65
Other6.1%5-506.1%5-505.0%5-50
PSO
202220212020
Functional Class of PropertyAnnual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
(in years)(in years)(in years)
Generation3.1%30-752.8%30-753.1%35-75
Transmission2.5%42-752.4%42-752.2%45-75
Distribution2.9%15-782.9%15-782.9%15-78
Other6.8%5-566.1%5-565.7%5-64
SWEPCo
202220212020
Functional Class of PropertyAnnual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
Annual Composite
Depreciation Rate
Depreciable
Life Ranges
(in years)(in years)(in years)
Generation2.7%30-652.7%30-652.7%35-65
Transmission2.3%44-702.4%49-742.3%47-73
Distribution2.9%15-752.8%15-802.7%15-67
Other9.0%5-578.6%5-588.5%5-52

The following table includes the nonregulated annual composite depreciation rate ranges and nonregulated depreciable life ranges for AEP. Depreciation rate ranges and depreciable life ranges are not meaningful for nonregulated property of AEP Texas, AEPTCo, APCo, I&M, OPCo, PSO and SWEPCo for 2022, 2021 and 2020.
202220212020
Functional Class of PropertyAnnual Composite
Depreciation Rate Ranges
Depreciable
Life Ranges
Annual Composite
Depreciation Rate Ranges
Depreciable
Life Ranges
Annual Composite
Depreciation Rate Ranges
Depreciable
Life Ranges
(in years)(in years)(in years)
Generation3.8%-8.7%3-613.8%-10.4%10-593.6%-4.0%15-59
Transmission2.8%10-622.6%30-402.5%30-40
DistributionNANANANANANA
Other25.2%5-35(a)16.5%5-35(a)16.1%5-50

(a)In 2020 management announced plans to retire the Pirkey Plant in 2023 and the related depreciable lives have been adjusted accordingly. See Note 5 - Effects of Regulation for additional information.
NA Not applicable.

SWEPCo provides for depreciation, depletion and amortization of coal-mining assets over each asset’s estimated useful life or the estimated life of each mine, whichever is shorter, using the straight-line method for mining structures and equipment.  SWEPCo uses either the straight-line method or the units-of-production method to amortize mine development costs and deplete coal rights based on estimated recoverable tonnages.  SWEPCo includes these costs in fuel expense.

For regulated operations, the composite depreciation rate generally includes a component for non-ARO removal costs, which is credited to Accumulated Depreciation and Amortization on the balance sheets.  Actual removal costs incurred are charged to Accumulated Depreciation and Amortization.  Any excess of accrued non-ARO removal costs over actual removal costs incurred is reclassified from Accumulated Depreciation and Amortization and reflected as a regulatory liability.  For nonregulated operations, non-ARO removal costs are expensed as incurred. 
Asset Retirement Obligations (Applies to all Registrants except AEPTCo)

The Registrants recorded the following revisions to ARO estimates as of December 31, 2022 and 2021:

As of December 31, 2022 and 2021, I&M’s ARO liability for nuclear decommissioning of the Cook Plant was $2 billion and $1.93 billion, respectively.  These liabilities are reflected in Asset Retirement Obligations on I&M’s balance sheets.  As of December 31, 2022 and 2021, the fair value of I&M’s assets that are legally restricted for purposes of settling decommissioning liabilities totaled $3.01 billion and $3.54 billion, respectively.  These assets are included in Spent Nuclear Fuel and Decommissioning Trusts on I&M’s balance sheets. In December 2021, I&M recorded a $58 million revision for Cook Plant as a result of the latest decommissioning cost study. The ARO liability was updated and changes from the previous study were driven primarily by general increases in the projected cost of labor and materials.
In 2020, Virginia’s Governor signed House Bill 443 (HB 443) requiring APCo to close certain ash disposal units at the retired Glen Lyn Station by removal of all coal combustion material. In June 2021, management completed fully designed and costed project plans for the Glen Lyn Station site and increased ash disposal ARO liabilities by an additional $79 million. HB 443 provides for the recovery of all costs associated with closure by removal through the Virginia environmental rate adjustment clause. APCo is permitted to record carrying costs on the unrecovered balance of closure costs as a weighted-average cost of capital approved by the Virginia SCC. The legislation provides for regulatory recovery of these costs.
In September 2022, APCo recorded a $14 million revision due to an increase in estimated ash pond closure costs at the Amos Plant.
In March 2022, PSO and SWEPCo acquired respective undivided ownership interests in the entity that owned Traverse during its development and construction. Immediately following the acquisition, PSO and SWEPCo liquidated the entity and simultaneously distributed the Traverse assets in proportion to their undivided ownership interests. Traverse was placed in-service in March 2022. As a result, PSO and SWEPCo incurred additional ARO liabilities of $13 million and $15 million, respectively. See the “North Central Wind Energy Facilities” section of Note 7 for additional information.
In March 2022, SWEPCo recorded a $13 million revision due to an increase in estimated ash pond closure costs at the Pirkey Plant and the Welsh Plant. In June 2022, SWEPCo recorded a $16 million revision due to an increase in estimated reclamation costs at Sabine. In September 2022, SWEPCo recorded a $14 million revision due to an increase in estimated landfill closure costs at Pirkey Plant. In November 2022, SWEPCo recorded an additional $7 million revision related to an increase in estimated reclamation costs at Sabine.

The following is a reconciliation of the 2022 and 2021 aggregate carrying amounts of ARO by Registrant:
CompanyARO as of December 31, 2021Accretion
Expense
Liabilities
Incurred
Liabilities
Settled
Revisions in
Cash Flow
Estimates (a)
ARO as of December 31, 2022
(in millions)
AEP(b)(c)(d)(e)(f)(g)(h)$2,741.7 $111.2 $37.4 $(47.0)$100.3 $2,943.6 
AEP Texas (b)(e)4.4 0.3 — (0.2)— 4.5 
APCo (b)(e)404.6 15.8 3.0 (12.7)17.0 427.7 
I&M (b)(c)(e)1,946.3 71.5 3.2 (0.6)7.7 2,028.1 
OPCo (e)1.9 0.2 3.0 (0.1)— 5.0 
PSO (b)(e)(g)57.6 4.1 12.8 (0.7)1.9 75.7 
SWEPCo (b)(d)(e)(g)222.7 11.9 15.4 (25.8)56.7 280.9 
CompanyARO as of December 31, 2020Accretion
Expense
Liabilities
Incurred
Liabilities
Settled
Revisions in
Cash Flow
Estimates (a)
ARO as of December 31, 2021
(in millions)
AEP (b)(c)(d)(e)(f)(g)(h)$2,516.7 $105.0 $22.8 $(41.4)$138.6 $2,741.7 
AEP Texas (b)(e)4.6 0.2 — (0.4)— 4.4 
APCo (b)(e)313.1 13.7 — (6.9)84.7 404.6 
I&M (b)(c)(e)1,813.8 72.9 0.3 (0.1)59.4 1,946.3 
OPCo (e)1.9 0.1 — (0.1)— 1.9 
PSO (b)(e)(g)47.4 3.3 7.6 (0.7)— 57.6 
SWEPCo (b)(d)(e)(g)222.1 9.8 9.2 (20.9)2.5 222.7 

(a)Unless discussed above, primarily related to ash ponds, landfills and mine reclamation, generally due to changes in estimated closure area, volumes and/or unit costs.
(b)Includes ARO related to ash disposal facilities.
(c)Includes ARO related to nuclear decommissioning costs for the Cook Plant of $2 billion and $1.93 billion as of December 31, 2022 and 2021, respectively.
(d)Includes ARO related to Sabine and DHLC.
(e)Includes ARO related to asbestos removal.
(f)Includes ARO related to solar farms.
(g)Includes ARO related to wind farms.
(h)Includes $18 million and $18 million as of December 31, 2022 and 2021, respectively, of ARO classified as Liabilities Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

Allowance for Funds Used During Construction and Interest Capitalization

The Registrants’ amounts of Allowance for Equity Funds Used During Construction are summarized in the following table:
Years Ended December 31,
Company202220212020
(in millions)
AEP$133.7 $139.7 $148.1 
AEP Texas19.7 21.5 19.4 
AEPTCo70.7 67.2 74.0 
APCo11.7 15.6 14.6 
I&M9.8 12.8 11.5 
OPCo13.9 10.8 12.5 
PSO1.5 2.4 4.0 
SWEPCo4.9 7.0 7.7 

The Registrants’ amounts of allowance for borrowed funds used during construction, including capitalized interest, are summarized in the following table:
Years Ended December 31,
Company202220212020
(in millions)
AEP$63.0 $53.8 $66.0 
AEP Texas11.5 10.5 12.5 
AEPTCo22.4 21.0 25.5 
APCo6.5 7.5 7.9 
I&M5.7 5.1 5.7 
OPCo6.7 4.7 6.2 
PSO2.7 0.7 2.0 
SWEPCo4.3 3.0 3.9 
Jointly-owned Electric Facilities (Applies to AEP, I&M, PSO and SWEPCo)

The Registrants have electric facilities that are jointly-owned with affiliated and nonaffiliated companies.  Using its own financing, each participating company is obligated to pay its share of the costs of these jointly-owned facilities in the same proportion as its ownership interest.  Each Registrant’s proportionate share of the operating costs associated with these facilities is included in its statements of income and the investments and accumulated depreciation are reflected in its balance sheets under Property, Plant and Equipment as follows:
Registrant’s Share as of December 31, 2022
Fuel
Type
Percent of
Ownership
Utility Plant
in Service
Construction
Work in
Progress
Accumulated
Depreciation
(in millions)
AEP
Flint Creek Generating Station, Unit 1 (a)Coal50.0 %$382.9 $16.4 $149.4 
Pirkey Plant, Unit 1 (a)Lignite85.9 %632.0 — 632.0 
Turk Generating Plant (a)Coal73.3 %1,611.1 5.1 314.7 
Total
$2,626.0 $21.5 $1,096.1 
I&M
Rockport Generating Plant (b)(c)(d)Coal50.0 %$1,357.4 $9.2 $905.1 
PSO
North Central Wind Energy Facilities (e)(f)Wind45.5 %$889.3 $9.1 $28.1 
SWEPCo
Flint Creek Generating Station, Unit 1 (a)Coal50.0 %$382.9 $16.4 $149.4 
Pirkey Plant, Unit 1 (a)Lignite85.9 %632.0 — 632.0 
Turk Generating Plant (a)Coal73.3 %1,611.1 5.1 314.7 
North Central Wind Energy Facilities (e)(f)Wind54.5 %1,066.8 10.1 35.2 
Total$3,692.8 $31.6 $1,131.3 
Registrant’s Share as of December 31, 2021
Fuel
Type
Percent of
Ownership
Utility Plant
in Service
Construction
Work in
Progress
Accumulated
Depreciation
(in millions)
AEP
Flint Creek Generating Station, Unit 1 (a)Coal50.0 %$377.6 $6.3 $133.5 
Pirkey Plant, Unit 1 (a)Lignite85.9 %613.8 — 528.3 
Turk Generating Plant (a)Coal73.3 %1,598.0 10.2 285.6 
Total
$2,589.4 $16.5 $947.4 
I&M
Rockport Generating Plant (b)(c)(d)Coal50.0 %$1,247.2 $13.9 $794.5 
PSO
North Central Wind Energy Facilities (e)(f)Wind45.5 %$313.7 $— $4.2 
SWEPCo
Flint Creek Generating Station, Unit 1 (a)Coal50.0 %$377.6 $6.3 $133.5 
Pirkey Plant, Unit 1 (a)Lignite85.9 %613.8 — 528.3 
Turk Generating Plant (a)Coal73.3 %1,598.0 10.2 285.6 
North Central Wind Energy Facilities (e)(f)Wind54.5 %376.2 — 5.4 
Total
$2,965.6 $16.5 $952.8 

(a)Operated by SWEPCo.
(b)Operated by I&M.
(c)Amounts include I&M's 50% ownership of both Unit 1 and capital additions for Unit 2. Unit 2 was subject to a finance lease with a nonaffiliated company. In December 2022, the lease expired at which point I&M and AEGCo acquired 100% of the interests in Unit 2. See the "Rockport Plant Litigation" section of Note 6 for additional information.
(d)AEGCo owns 50%.
(e)PSO and SWEPCo own undivided interests of 45.5% and 54.5% of the NCWF, respectively. Sundance was placed into service in April 2021. Maverick was placed into service in September 2021. Traverse was placed into service in March 2022. See the “Acquisitions” section of Note 7 for additional information.
(f)Operated by PSO.
   
Kentucky Power Co [Member]      
Depreciation, Depletion and Amortization      
Assets Held for Sale $ 2,400.0 2,300.0  
Kentucky Transmission Company      
Depreciation, Depletion and Amortization      
Assets Held for Sale 170.0 165.0  
Kentucky Power Co [Member]      
Asset Retirement Obligations (ARO)      
Liabilities Held for Sale 18.0 18.0  
AEP Texas Inc. [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Transmission 6,301.5 5,849.9  
Property, Plant and Equipment, Distribution 5,312.8 4,917.2  
Property, Plant and Equipment, Other 1,022.8 961.1  
Property, Plant and Equipment, Construction Work in Progress 805.2 551.3  
Accumulated Depreciation 1,760.7 1,644.1  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 11,681.6 10,635.4  
Asset Retirement Obligations (ARO)      
Beginning Balance [4],[5] 4.4 4.6  
Accretion Expense [4],[5] 0.3 0.2  
Liabilities Incurred [4],[5] 0.0 0.0  
Liabilities Settled [4],[5] (0.2) (0.4)  
Revisions in Cash Flow Estimates [4],[5],[9] 0.0 0.0  
Ending Balance [4],[5] 4.5 4.4 4.6
Allowance for Funds Used During Construction (AFUDC) and Interest Capitalization      
Allowance for Equity Funds Used During Construction 19.7 21.5 19.4
Allowance for Borrowed Funds Used During Construction 11.5 10.5 12.5
AEP Transmission Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Transmission 12,183.2 10,886.3  
Property, Plant and Equipment, Other 451.9 427.4  
Property, Plant and Equipment, Construction Work in Progress 1,547.1 1,394.8  
Accumulated Depreciation 1,012.1 772.8  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET [10] 13,170.1 11,935.7  
Assets Held for Sale 178.0 167.9  
Asset Retirement Obligations (ARO)      
Liabilities Held for Sale 28.6 27.6  
Allowance for Funds Used During Construction (AFUDC) and Interest Capitalization      
Allowance for Equity Funds Used During Construction 70.7 67.2 74.0
Allowance for Borrowed Funds Used During Construction 22.4 21.0 25.5
Appalachian Power Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation 6,776.8 6,683.9  
Property, Plant and Equipment, Transmission 4,482.8 4,322.4  
Property, Plant and Equipment, Distribution 4,933.0 4,683.3  
Property, Plant and Equipment, Other 883.3 696.6  
Property, Plant and Equipment, Construction Work in Progress 705.3 469.9  
Accumulated Depreciation 5,402.0 5,051.8  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 12,379.2 11,804.3  
Asset Retirement Obligations (ARO)      
Beginning Balance [4],[5] 404.6 313.1  
Accretion Expense [4],[5] 15.8 13.7  
Liabilities Incurred [4],[5] 3.0 0.0  
Liabilities Settled [4],[5] (12.7) (6.9)  
Revisions in Cash Flow Estimates [4],[5],[9] 17.0 84.7  
Ending Balance [4],[5] 427.7 404.6 313.1
Allowance for Funds Used During Construction (AFUDC) and Interest Capitalization      
Allowance for Equity Funds Used During Construction 11.7 15.6 14.6
Allowance for Borrowed Funds Used During Construction 6.5 7.5 7.9
Jointly-owned Electric Facilities      
Asset Impairments and Other Related Charges 24.9 0.0 0.0
Indiana Michigan Power Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation 5,585.1 5,531.8  
Property, Plant and Equipment, Transmission 1,842.2 1,783.1  
Property, Plant and Equipment, Distribution 3,024.7 2,800.1  
Property, Plant and Equipment, Other 839.3 792.9  
Property, Plant and Equipment, Construction Work in Progress 253.0 302.8  
Accumulated Depreciation 4,132.8 3,899.8  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 7,411.5 7,310.9  
Asset Retirement Obligations (ARO)      
Beginning Balance [4],[5],[6] 1,946.3 1,813.8  
Accretion Expense [4],[5],[6] 71.5 72.9  
Liabilities Incurred [4],[5],[6] 3.2 0.3  
Liabilities Settled [4],[5],[6] (0.6) (0.1)  
Revisions in Cash Flow Estimates [4],[5],[6],[9] 7.7 59.4  
Ending Balance [4],[5],[6] 2,028.1 1,946.3 1,813.8
Asset Retirement Obligations (ARO) Liability for Nuclear Decommissioning of the Cook Plant 2,000.0 1,930.0  
Fair Value of Legally Restricted Assets 3,010.0 3,540.0  
Allowance for Funds Used During Construction (AFUDC) and Interest Capitalization      
Allowance for Equity Funds Used During Construction 9.8 12.8 11.5
Allowance for Borrowed Funds Used During Construction 5.7 5.1 5.7
Ohio Power Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Transmission 3,198.6 2,992.8  
Property, Plant and Equipment, Distribution 6,450.3 6,070.6  
Property, Plant and Equipment, Other 1,051.4 992.9  
Property, Plant and Equipment, Construction Work in Progress 474.3 365.0  
Accumulated Depreciation 2,565.3 2,458.3  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 8,609.3 7,963.0  
Asset Retirement Obligations (ARO)      
Beginning Balance [4] 1.9 1.9  
Accretion Expense [4] 0.2 0.1  
Liabilities Incurred [4] 3.0 0.0  
Liabilities Settled [4] (0.1) (0.1)  
Revisions in Cash Flow Estimates [4],[9] 0.0 0.0  
Ending Balance [4] 5.0 1.9 1.9
Allowance for Funds Used During Construction (AFUDC) and Interest Capitalization      
Allowance for Equity Funds Used During Construction 13.9 10.8 12.5
Allowance for Borrowed Funds Used During Construction 6.7 4.7 6.2
Public Service Co Of Oklahoma [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation 2,394.8 1,802.4  
Property, Plant and Equipment, Transmission 1,164.4 1,107.7  
Property, Plant and Equipment, Distribution 3,216.4 3,004.9  
Property, Plant and Equipment, Other 469.3 437.0  
Property, Plant and Equipment, Construction Work in Progress 219.3 156.0  
Accumulated Depreciation 1,837.7 1,705.2  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 5,626.5 4,802.8  
Asset Retirement Obligations (ARO)      
Beginning Balance [4],[5],[8] 57.6 47.4  
Accretion Expense [4],[5],[8] 4.1 3.3  
Liabilities Incurred [4],[5],[8] 12.8 7.6  
Liabilities Settled [4],[5],[8] (0.7) (0.7)  
Revisions in Cash Flow Estimates [4],[5],[8],[9] 1.9 0.0  
Ending Balance [4],[5],[8] 75.7 57.6 47.4
Allowance for Funds Used During Construction (AFUDC) and Interest Capitalization      
Allowance for Equity Funds Used During Construction 1.5 2.4 4.0
Allowance for Borrowed Funds Used During Construction 2.7 0.7 2.0
Southwestern Electric Power Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation 5,476.2 4,734.5  
Property, Plant and Equipment, Transmission 2,479.8 2,316.9  
Property, Plant and Equipment, Distribution 2,659.6 2,514.3  
Property, Plant and Equipment, Other 804.4 764.0  
Property, Plant and Equipment, Construction Work in Progress 369.5 240.7  
Accumulated Depreciation 3,527.3 3,170.3  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 8,262.2 7,400.1  
Asset Retirement Obligations (ARO)      
Beginning Balance [3],[4],[5],[8] 222.7 222.1  
Accretion Expense [3],[4],[5],[8] 11.9 9.8  
Liabilities Incurred [3],[4],[5],[8] 15.4 9.2  
Liabilities Settled [3],[4],[5],[8] (25.8) (20.9)  
Revisions in Cash Flow Estimates [3],[4],[5],[8],[9] 56.7 2.5  
Ending Balance [3],[4],[5],[8] 280.9 222.7 222.1
Allowance for Funds Used During Construction (AFUDC) and Interest Capitalization      
Allowance for Equity Funds Used During Construction 4.9 7.0 7.7
Allowance for Borrowed Funds Used During Construction 4.3 3.0 3.9
Jointly-owned Electric Facilities      
Utility Plant in Service 3,692.8 2,965.6  
Construction Work in Progress 31.6 16.5  
Accumulated Depreciation 1,131.3 952.8  
Asset Impairments and Other Related Charges $ 0.0 $ 11.6 $ 0.0
Flint Creek Generating Station (Unit No. 1) [Member] | Coal [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership [11] 50.00% 50.00%  
Utility Plant in Service [11] $ 382.9 $ 377.6  
Construction Work in Progress [11] 16.4 6.3  
Accumulated Depreciation [11] $ 149.4 $ 133.5  
Flint Creek Generating Station (Unit No. 1) [Member] | Southwestern Electric Power Co [Member] | Coal [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership [11] 50.00% 50.00%  
Utility Plant in Service [11] $ 382.9 $ 377.6  
Construction Work in Progress [11] 16.4 6.3  
Accumulated Depreciation [11] $ 149.4 $ 133.5  
Pirkey Generating Station (Unit No. 1) [Member] | Public Utilities, Inventory, Lignite [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership [11] 85.90% 85.90%  
Utility Plant in Service [11] $ 632.0 $ 613.8  
Construction Work in Progress [11] 0.0 0.0  
Accumulated Depreciation [11] $ 632.0 $ 528.3  
Pirkey Generating Station (Unit No. 1) [Member] | Southwestern Electric Power Co [Member] | Public Utilities, Inventory, Lignite [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership [11] 85.90% 85.90%  
Utility Plant in Service [11] $ 632.0 $ 613.8  
Construction Work in Progress [11] 0.0 0.0  
Accumulated Depreciation [11] $ 632.0 $ 528.3  
Turk Generating Plant [Member] | Coal [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership [11] 73.30% 73.30%  
Utility Plant in Service [11] $ 1,611.1 $ 1,598.0  
Construction Work in Progress [11] 5.1 10.2  
Accumulated Depreciation [11] $ 314.7 $ 285.6  
Turk Generating Plant [Member] | Southwestern Electric Power Co [Member] | Coal [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership [11] 73.30% 73.30%  
Utility Plant in Service [11] $ 1,611.1 $ 1,598.0  
Construction Work in Progress [11] 5.1 10.2  
Accumulated Depreciation [11] $ 314.7 $ 285.6  
Rockport Generating Plant (Unit No. 2) [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership 100.00%    
NCWF [Member] | Public Service Co Of Oklahoma [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership 45.50%    
NCWF [Member] | Public Service Co Of Oklahoma [Member] | Wind [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership [12],[13] 45.50% 45.50%  
Utility Plant in Service [12],[13] $ 889.3 $ 313.7  
Construction Work in Progress [12],[13] 9.1 0.0  
Accumulated Depreciation [12],[13] $ 28.1 $ 4.2  
NCWF [Member] | Southwestern Electric Power Co [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership 54.50%    
NCWF [Member] | Southwestern Electric Power Co [Member] | Wind [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership [12],[13] 54.50% 54.50%  
Utility Plant in Service [12],[13] $ 1,066.8 $ 376.2  
Construction Work in Progress [12],[13] 10.1 0.0  
Accumulated Depreciation [12],[13] $ 35.2 $ 5.4  
Rockport Generating Plant | Indiana Michigan Power Co [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership 50.00%    
Rockport Generating Plant | Indiana Michigan Power Co [Member] | Coal [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership [14],[15],[16] 50.00% 50.00%  
Utility Plant in Service [14],[15],[16] $ 1,357.4 $ 1,247.2  
Construction Work in Progress [14],[15],[16] 9.2 13.9  
Accumulated Depreciation [14],[15],[16] $ 905.1 794.5  
Rockport Generating Plant | AEP Generating Co [Member]      
Jointly-owned Electric Facilities      
Percent of Ownership 50.00%    
Regulated Operation [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation [17] $ 22,523.1 21,196.8  
Property, Plant and Equipment, Transmission 32,267.8 29,866.0  
Property, Plant and Equipment, Distribution 26,077.2 24,440.0  
Property, Plant and Equipment, Other 5,700.4 5,249.8  
Property, Plant and Equipment, Construction Work in Progress [17] 4,630.8 3,632.4  
Accumulated Depreciation 21,947.1 20,375.5  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 69,252.2 $ 64,009.5  
Regulated Operation [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 132 years 132 years 132 years
Depreciable Life Ranges - Transmission 75 years 75 years 75 years
Depreciable Life Ranges - Distribution 78 years 80 years 78 years
Depreciable Life Ranges - Other 75 years 75 years 75 years
Regulated Operation [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 20 years 20 years 20 years
Depreciable Life Ranges - Transmission 24 years 15 years 15 years
Depreciable Life Ranges - Distribution 7 years 7 years 7 years
Depreciable Life Ranges - Other 5 years 5 years 5 years
Regulated Operation [Member] | Generation [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 7.60% 7.80% 6.30%
Regulated Operation [Member] | Generation [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.70% 2.70% 2.70%
Regulated Operation [Member] | Transmission [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.70% 2.60% 2.60%
Regulated Operation [Member] | Transmission [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.00% 2.00% 2.00%
Regulated Operation [Member] | Distribution [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 3.60% 3.60% 3.70%
Regulated Operation [Member] | Distribution [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.70% 2.80% 2.70%
Regulated Operation [Member] | Other Property Class [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 14.40% 12.50% 11.30%
Regulated Operation [Member] | Other Property Class [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 3.10% 3.00% 2.80%
Regulated Operation [Member] | AEP Texas Inc. [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation $ 0.0 $ 0.0  
Property, Plant and Equipment, Transmission 6,301.5 5,849.9  
Property, Plant and Equipment, Distribution 5,312.8 4,917.2  
Property, Plant and Equipment, Other 1,020.4 958.7  
Property, Plant and Equipment, Construction Work in Progress 805.2 551.3  
Accumulated Depreciation 1,759.5 1,642.9  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 11,680.4 $ 10,634.2  
Regulated Operation [Member] | AEP Texas Inc. [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Transmission 75 years 75 years 75 years
Depreciable Life Ranges - Distribution 70 years 70 years 70 years
Depreciable Life Ranges - Other 50 years 50 years 50 years
Regulated Operation [Member] | AEP Texas Inc. [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Transmission 50 years 50 years 50 years
Depreciable Life Ranges - Distribution 7 years 7 years 7 years
Depreciable Life Ranges - Other 5 years 5 years 5 years
Regulated Operation [Member] | AEP Texas Inc. [Member] | Transmission [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.20% 2.20% 2.00%
Regulated Operation [Member] | AEP Texas Inc. [Member] | Distribution [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.90% 2.90% 3.10%
Regulated Operation [Member] | AEP Texas Inc. [Member] | Other Property Class [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 6.20% 5.80% 6.10%
Regulated Operation [Member] | AEP Transmission Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation $ 0.0 $ 0.0  
Property, Plant and Equipment, Transmission 12,183.2 10,886.3  
Property, Plant and Equipment, Distribution 0.0 0.0  
Property, Plant and Equipment, Other 451.7 427.2  
Property, Plant and Equipment, Construction Work in Progress 1,547.1 1,394.8  
Accumulated Depreciation 1,012.2 772.9  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 13,169.8 $ 11,935.4  
Regulated Operation [Member] | AEP Transmission Co [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Transmission 75 years 75 years 75 years
Depreciable Life Ranges - Other 56 years 56 years 64 years
Regulated Operation [Member] | AEP Transmission Co [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Transmission 24 years 24 years 24 years
Depreciable Life Ranges - Other 5 years 5 years 5 years
Regulated Operation [Member] | AEP Transmission Co [Member] | Transmission [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.60% 2.50% 2.40%
Regulated Operation [Member] | AEP Transmission Co [Member] | Other Property Class [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 6.60% 6.70% 6.30%
Regulated Operation [Member] | Appalachian Power Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation $ 6,776.8 $ 6,683.9  
Property, Plant and Equipment, Transmission 4,482.8 4,322.4  
Property, Plant and Equipment, Distribution 4,933.0 4,683.3  
Property, Plant and Equipment, Other 849.2 668.9  
Property, Plant and Equipment, Construction Work in Progress 705.3 469.9  
Accumulated Depreciation 5,397.3 5,047.4  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 12,349.8 $ 11,781.0  
Regulated Operation [Member] | Appalachian Power Co [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 118 years 118 years 118 years
Depreciable Life Ranges - Transmission 75 years 75 years 75 years
Depreciable Life Ranges - Distribution 57 years 57 years 57 years
Depreciable Life Ranges - Other 55 years 55 years 55 years
Regulated Operation [Member] | Appalachian Power Co [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 35 years 35 years 35 years
Depreciable Life Ranges - Transmission 24 years 15 years 15 years
Depreciable Life Ranges - Distribution 12 years 12 years 12 years
Depreciable Life Ranges - Other 5 years 5 years 5 years
Regulated Operation [Member] | Appalachian Power Co [Member] | Generation [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 3.60% 3.60% 3.30%
Regulated Operation [Member] | Appalachian Power Co [Member] | Transmission [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.20% 2.10% 2.20%
Regulated Operation [Member] | Appalachian Power Co [Member] | Distribution [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 3.60% 3.50% 3.70%
Regulated Operation [Member] | Appalachian Power Co [Member] | Other Property Class [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 7.30% 8.50% 7.80%
Regulated Operation [Member] | Indiana Michigan Power Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation $ 5,534.6 $ 5,531.8  
Property, Plant and Equipment, Transmission 1,842.2 1,783.1  
Property, Plant and Equipment, Distribution 3,024.7 2,800.1  
Property, Plant and Equipment, Other 796.1 755.1  
Property, Plant and Equipment, Construction Work in Progress 253.0 302.8  
Accumulated Depreciation 4,117.8 3,885.3  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 7,332.8 $ 7,287.6  
Regulated Operation [Member] | Indiana Michigan Power Co [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 132 years 132 years 132 years
Depreciable Life Ranges - Transmission 67 years 70 years 70 years
Depreciable Life Ranges - Distribution 71 years 71 years 71 years
Depreciable Life Ranges - Other 45 years 51 years 51 years
Regulated Operation [Member] | Indiana Michigan Power Co [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 20 years 20 years 20 years
Depreciable Life Ranges - Transmission 44 years 45 years 45 years
Depreciable Life Ranges - Distribution 14 years 14 years 14 years
Depreciable Life Ranges - Other 5 years 5 years 5 years
Regulated Operation [Member] | Indiana Michigan Power Co [Member] | Generation [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 4.90% 4.70% 4.60%
Regulated Operation [Member] | Indiana Michigan Power Co [Member] | Transmission [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.50% 2.40% 2.30%
Regulated Operation [Member] | Indiana Michigan Power Co [Member] | Distribution [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 3.10% 3.40% 3.40%
Regulated Operation [Member] | Indiana Michigan Power Co [Member] | Other Property Class [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 10.10% 9.00% 10.20%
Regulated Operation [Member] | Ohio Power Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation $ 0.0 $ 0.0  
Property, Plant and Equipment, Transmission 3,198.6 2,992.8  
Property, Plant and Equipment, Distribution 6,450.3 6,070.6  
Property, Plant and Equipment, Other 1,040.6 982.2  
Property, Plant and Equipment, Construction Work in Progress 474.3 365.0  
Accumulated Depreciation 2,564.3 2,457.4  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 8,599.5 $ 7,953.2  
Regulated Operation [Member] | Ohio Power Co [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Transmission 60 years 60 years 60 years
Depreciable Life Ranges - Distribution 70 years 70 years 65 years
Depreciable Life Ranges - Other 50 years 50 years 50 years
Regulated Operation [Member] | Ohio Power Co [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Transmission 39 years 39 years 39 years
Depreciable Life Ranges - Distribution 11 years 11 years 14 years
Depreciable Life Ranges - Other 5 years 5 years 5 years
Regulated Operation [Member] | Ohio Power Co [Member] | Transmission [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.30% 2.30% 2.30%
Regulated Operation [Member] | Ohio Power Co [Member] | Distribution [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.70% 2.90% 3.10%
Regulated Operation [Member] | Ohio Power Co [Member] | Other Property Class [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 6.10% 6.10% 5.00%
Regulated Operation [Member] | Public Service Co Of Oklahoma [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation $ 2,394.8 $ 1,802.4  
Property, Plant and Equipment, Transmission 1,164.4 1,107.7  
Property, Plant and Equipment, Distribution 3,216.4 3,004.9  
Property, Plant and Equipment, Other 466.0 433.5  
Property, Plant and Equipment, Construction Work in Progress 219.3 156.0  
Accumulated Depreciation 1,839.4 1,707.0  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 5,621.5 $ 4,797.5  
Regulated Operation [Member] | Public Service Co Of Oklahoma [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 75 years 75 years 75 years
Depreciable Life Ranges - Transmission 75 years 75 years 75 years
Depreciable Life Ranges - Distribution 78 years 78 years 78 years
Depreciable Life Ranges - Other 56 years 56 years 64 years
Regulated Operation [Member] | Public Service Co Of Oklahoma [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 30 years 30 years 35 years
Depreciable Life Ranges - Transmission 42 years 42 years 45 years
Depreciable Life Ranges - Distribution 15 years 15 years 15 years
Depreciable Life Ranges - Other 5 years 5 years 5 years
Regulated Operation [Member] | Public Service Co Of Oklahoma [Member] | Generation [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 3.10% 2.80% 3.10%
Regulated Operation [Member] | Public Service Co Of Oklahoma [Member] | Transmission [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.50% 2.40% 2.20%
Regulated Operation [Member] | Public Service Co Of Oklahoma [Member] | Distribution [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.90% 2.90% 2.90%
Regulated Operation [Member] | Public Service Co Of Oklahoma [Member] | Other Property Class [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 6.80% 6.10% 5.70%
Regulated Operation [Member] | Southwestern Electric Power Co [Member]      
Depreciation, Depletion and Amortization      
Property, Plant and Equipment, Generation [17] $ 5,476.2 $ 4,734.5  
Property, Plant and Equipment, Transmission 2,479.8 2,316.9  
Property, Plant and Equipment, Distribution 2,659.6 2,514.3  
Property, Plant and Equipment, Other 582.6 542.0  
Property, Plant and Equipment, Construction Work in Progress [17] 369.5 240.7  
Accumulated Depreciation 3,314.8 3,002.2  
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 8,252.9 $ 7,346.2  
Regulated Operation [Member] | Southwestern Electric Power Co [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 65 years 65 years 65 years
Depreciable Life Ranges - Transmission 70 years 74 years 73 years
Depreciable Life Ranges - Distribution 75 years 80 years 67 years
Depreciable Life Ranges - Other 57 years 58 years 52 years
Regulated Operation [Member] | Southwestern Electric Power Co [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 30 years 30 years 35 years
Depreciable Life Ranges - Transmission 44 years 49 years 47 years
Depreciable Life Ranges - Distribution 15 years 15 years 15 years
Depreciable Life Ranges - Other 5 years 5 years 5 years
Regulated Operation [Member] | Southwestern Electric Power Co [Member] | Generation [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.70% 2.70% 2.70%
Regulated Operation [Member] | Southwestern Electric Power Co [Member] | Transmission [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.30% 2.40% 2.30%
Regulated Operation [Member] | Southwestern Electric Power Co [Member] | Distribution [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.90% 2.80% 2.70%
Regulated Operation [Member] | Southwestern Electric Power Co [Member] | Other Property Class [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 9.00% 8.60% 8.50%
Unregulated Operation [Member]      
Depreciation, Depletion and Amortization      
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 2,030.7 $ 1,991.8  
Unregulated Operation [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 61 years 59 years 59 years
Depreciable Life Ranges - Transmission 62 years 40 years 40 years
Depreciable Life Ranges - Other 35 years [18] 35 years [18] 50 years
Unregulated Operation [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Depreciable Life Ranges - Generation 3 years 10 years 15 years
Depreciable Life Ranges - Transmission 10 years 30 years 30 years
Depreciable Life Ranges - Other 5 years [18] 5 years [18] 5 years
Unregulated Operation [Member] | Generation [Member] | Maximum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 8.70% 10.40% 4.00%
Unregulated Operation [Member] | Generation [Member] | Minimum [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 3.80% 3.80% 3.60%
Unregulated Operation [Member] | Transmission [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 2.80% 2.60% 2.50%
Unregulated Operation [Member] | Other Property Class [Member]      
Depreciation, Depletion and Amortization      
Annual Composite Depreciation Rate 25.20% 16.50% 16.10%
Unregulated Operation [Member] | AEP Texas Inc. [Member]      
Depreciation, Depletion and Amortization      
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET $ 1.2 $ 1.2  
Unregulated Operation [Member] | AEP Transmission Co [Member]      
Depreciation, Depletion and Amortization      
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 0.3 0.3  
Unregulated Operation [Member] | Appalachian Power Co [Member]      
Depreciation, Depletion and Amortization      
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 29.4 23.3  
Unregulated Operation [Member] | Indiana Michigan Power Co [Member]      
Depreciation, Depletion and Amortization      
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 78.7 23.3  
Unregulated Operation [Member] | Ohio Power Co [Member]      
Depreciation, Depletion and Amortization      
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 9.8 9.8  
Unregulated Operation [Member] | Public Service Co Of Oklahoma [Member]      
Depreciation, Depletion and Amortization      
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 5.0 5.3  
Unregulated Operation [Member] | Southwestern Electric Power Co [Member]      
Depreciation, Depletion and Amortization      
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET 9.3 53.9  
Glen Lyn Station [Member] | Appalachian Power Co [Member]      
Asset Retirement Obligations (ARO)      
Revisions in Cash Flow Estimates   79.0  
Cook Nuclear Plant [Member] | Indiana Michigan Power Co [Member]      
Asset Retirement Obligations (ARO)      
Revisions in Cash Flow Estimates   58.0  
Amos Plant | Appalachian Power Co [Member]      
Asset Retirement Obligations (ARO)      
Revisions in Cash Flow Estimates 14.0    
Traverse [Member] | Public Service Co Of Oklahoma [Member]      
Asset Retirement Obligations (ARO)      
Liabilities Incurred 13.0    
Traverse [Member] | Southwestern Electric Power Co [Member]      
Asset Retirement Obligations (ARO)      
Liabilities Incurred 15.0    
Pirkey Power Plant | Southwestern Electric Power Co [Member]      
Asset Retirement Obligations (ARO)      
Revisions in Cash Flow Estimates 13.0    
Sabine Mining Co [Member] | Southwestern Electric Power Co [Member]      
Property, Plant and Equipment (Textuals)      
Asset Retirement Obligation, Revision of Estimate, Estimated Reclamation Costs - 1 16.0    
Asset Retirement Obligation, Revision of Estimate, Estimated Reclamation Costs - 2 7.0    
Pirkey Power Plant | Southwestern Electric Power Co [Member]      
Asset Retirement Obligations (ARO)      
Revisions in Cash Flow Estimates 14.0    
Generation and Marketing [Member]      
Jointly-owned Electric Facilities      
Asset Impairments and Other Related Charges $ 0.0 $ 0.0  
[1] Amount excludes $2.4 billion and $2.3 billion as of December 31, 2022 and 2021, respectively, of Property, Plant and Equipment - Net classified as Assets Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.
[2] Includes $18 million and $18 million as of December 31, 2022 and 2021, respectively, of ARO classified as Liabilities Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information
[3] Includes ARO related to Sabine and DHLC.
[4] Includes ARO related to asbestos removal.
[5] Includes ARO related to ash disposal facilities.
[6] Includes ARO related to nuclear decommissioning costs for the Cook Plant of $2 billion and $1.93 billion as of December 31, 2022 and 2021, respectively.
[7] Includes ARO related to solar farms.
[8] Includes ARO related to wind farms.
[9] Unless discussed above, primarily related to ash ponds, landfills and mine reclamation, generally due to changes in estimated closure area, volumes and/or unit costs.
[10] Amount excludes $170 million and $165 million as of December 31, 2022 and 2021, respectively, of Property, Plant and Equipment - Net classified as Assets Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.
[11] Operated by SWEPCo.
[12] Operated by PSO.
[13] PSO and SWEPCo own undivided interests of 45.5% and 54.5% of the NCWF, respectively. Sundance was placed into service in April 2021. Maverick was placed into service in September 2021. Traverse was placed into service in March 2022. See the “Acquisitions” section of Note 7 for additional information.
[14] AEGCo owns 50%.
[15] Amounts include I&M's 50% ownership of both Unit 1 and capital additions for Unit 2. Unit 2 was subject to a finance lease with a nonaffiliated company. In December 2022, the lease expired at which point I&M and AEGCo acquired 100% of the interests in Unit 2. See the "Rockport Plant Litigation" section of Note 6 for additional information.
[16] Operated by I&M.
[17] AEP and SWEPCo’s regulated generation and regulated CWIP include amounts related to SWEPCo’s Arkansas jurisdictional share of the Turk Plant.
[18] In 2020 management announced plans to retire the Pirkey Plant in 2023 and the related depreciable lives have been adjusted accordingly. See Note 5 - Effects of Regulation for additional information.