Organization and Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Materials and Supplies	$ 1,025.8	$ 915.1
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment	2,927.5	3,072.8	$ 2,717.1
Amortization of Certain Securitized Assets	91.9	93.3	64.2
Amortization of Regulatory Assets and Liabilities	71.0	36.7	44.4
Total Depreciation and Amortization	3,090.4	3,202.8	2,825.7
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period	509.4
Restricted Cash	48.9	47.1
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	379.0	556.5	451.4	$ 438.3
Amounts Attributable to AEP Common Shareholders
Net Income (Loss) Attributable to Noncontrolling Interests	4.5	(1.6)	0.0
Net Income (Loss)	$ 2,208.1	$ 2,307.2	$ 2,488.1
Weighted Average Number of Basic AEP Common Shares Outstanding	518,903,682	511,841,946	500,522,177
Earnings Per Share, Basic	$ 4.26	$ 4.51	$ 4.97
Weighted Average Dilutive Effect of:
Weighted Average Number of Diluted AEP Common Shares Outstanding	520,206,258	513,484,609	501,784,032
Earnings Per Share, Diluted	$ 4.24	$ 4.49	$ 4.96
Revenues
TOTAL REVENUES	$ 18,982.3	$ 19,639.5	$ 16,792.0
Expenses
Depreciation and Amortization	3,090.4	3,202.8	2,825.7
TOTAL EXPENSES	15,426.1	16,156.8	13,380.7
OPERATING INCOME (LOSS)	3,556.2	3,482.7	3,411.3
Other Income (Expense)
Allowance for Equity Funds Used During Construction	174.9	133.7	139.7
Interest Expense	(1,806.9)	(1,396.1)	(1,199.1)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)	2,208.7	2,420.4	2,511.9
Income Tax Expense (Benefit)	54.6	5.4	115.5
Net Income (Loss)	2,212.6	2,305.6	2,488.1
Accounts Receivable:
Customers	1,029.9	1,145.1
Total Accounts Receivable	2,447.4	2,668.0
Accrued Tax Benefits	156.2	99.4
TOTAL CURRENT ASSETS	6,082.1	6,775.5
Property, Plant and Equipment
Transmission	35,934.1	33,266.9
Other Property, Plant and Equipment	6,484.9	5,971.8
Construction Work in Progress	5,508.0	4,809.7
Total Property, Plant and Equipment	101,246.4	97,021.4
Accumulated Depreciation and Amortization	24,553.0	23,682.3
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	76,693.4	73,339.1
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS	13,908.5	13,288.7
TOTAL ASSETS	96,684.0	93,403.3
Current Liabilities
Accounts Payable	2,032.5	2,670.8
Accrued Taxes	1,800.1	1,714.6
TOTAL CURRENT LIABILITIES	11,583.6	13,266.3
Liabilities, Noncurrent
Regulatory Liabilities and Deferred Investment Tax Credits	8,182.4	8,115.6
TOTAL NONCURRENT LIABILITIES	59,772.0	55,968.7
TOTAL LIABILITIES	71,355.6	69,235.0
Equity [Abstract]
Retained Earnings	12,800.4	12,345.6
TOTAL LIABILITIES AND EQUITY	96,684.0	93,403.3
Operating Activites
Net Income (Loss)	2,212.6	2,305.6	2,488.1
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	3,090.4	3,202.8	2,825.7
Deferred Income Taxes	185.1	(137.2)	107.6
Allowance for Equity Funds Used During Construction	(174.9)	(133.7)	(139.7)
Amortization of Deferred Property Taxes	(41.1)	(41.2)	(68.0)
Change in Other Noncurrent Assets	(465.1)	(187.7)	(126.6)
Increase (Decrease) in Other Noncurrent Liabilities	29.0	337.8	206.4
Accounts Receivable, Net	236.5	(681.7)	(119.7)
Accounts Payable	(253.2)	489.2	200.6
Accrued Taxes, Net	22.5	105.4	218.7
Net Cash Flows from Operating Activities	5,012.2	5,288.0	3,839.9
Investing Activities
Net Cash Flows Used for Investing Activities	(6,266.7)	(7,751.8)	(6,433.9)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities	1,077.0	2,568.9	2,607.1
Cash and Cash Equivalents at Beginning of Period	509.4
Cash and Cash Equivalents at End of Period	330.1	509.4
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts	1,673.5	1,286.3	1,137.2
Income Taxes	78.4	116.8	13.2
Cash Received from the Sale of Transferable Tax Credits	(102.0)	0.0	0.0
Noncash Investing and Financing Activities:
Noncash Acquisition Under Finance Leases	48.7	31.8	287.6
Construction in Progress Expenditures Incurred but Not yet Paid	842.4	1,258.9	1,180.4
Construction Expenditures Included in Current Liabilities as of December 31,	842.4	1,258.9	1,180.4
Acquisition of Nuclear Fuel Included in Current Liabilities as of December 31,	24.2	0.0	0.0
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt	5,462.8	4,649.7	6,486.3
Repayments of Long-term Debt	$ 2,196.1	2,345.4	2,989.3
Equity Method Investment, Ownership Percentage	50.00%
Equity Method Investment	$ 1,073.6	1,276.7	1,447.5
Income (Loss) from Equity Method Investment	$ 58.5	$ (109.4)	91.7
Antidilutive Shares Outstanding	0	0
Net Income (Loss)	$ 2,212.6	$ 2,305.6	2,488.1
Retained Earnings	12,800.4	12,345.6
Cedar Creek Project
Noncash Investing and Financing Activities:
Noncash Contribution of Assets to Cedar Creek Project	0.0	0.0	(9.3)
Competitive Contracted Renewables
Noncash Investing and Financing Activities:
Noncash or Part Noncash Divestiture, Amount of Consideration Received	74.7	0.0	0.0
Retained Earnings [Member]
Amounts Attributable to AEP Common Shareholders
Net Income (Loss)	$ 2,208.1	2,307.2	2,488.1
Berkshire Hathaway [Member]
Organization and Summary of Significant Accounting Policies (Textuals)
Equity Method Investment, Ownership Percentage	50.00%
AEP Transmission Holdco [Member]
Organization and Summary of Significant Accounting Policies (Textuals)
Equity Method Investment, Ownership Percentage	50.00%
Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	30.00%
Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	54.00%
Pension Plans [Member] | Other Investments [Member]
Target Asset Allocations
Target Asset Allocation	15.00%
Pension Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Other Postretirement Benefit Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	58.00%
Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	41.00%
Other Postretirement Benefit Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Pension and Other Postretirement Benefit Plans [Member]
Supplementary Information
Securities Loaned	$ 62.0	83.0
AEP Texas Inc. [Member]
Materials and Supplies	190.4	138.8
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment	380.0	363.5	327.2
Amortization of Certain Securitized Assets	91.9	93.3	64.2
Amortization of Regulatory Assets and Liabilities	(3.4)	(4.4)	(4.4)
Total Depreciation and Amortization	468.5	452.4	387.0
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period	0.1
Restricted Cash	34.0	32.7
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	34.1	32.8	30.5	28.8
Revenues
TOTAL REVENUES	1,901.9	1,846.8	1,593.8
Expenses
Depreciation and Amortization	468.5	452.4	387.0
TOTAL EXPENSES	1,262.8	1,297.6	1,117.8
OPERATING INCOME (LOSS)	639.1	549.2	476.0
Other Income (Expense)
Allowance for Equity Funds Used During Construction	28.4	19.7	21.5
Interest Expense	(232.7)	(208.7)	(176.5)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)	456.3	380.5	332.9
Income Tax Expense (Benefit)	85.9	72.6	43.1
Net Income (Loss)	370.4	307.9	289.8
Accounts Receivable:
Customers	176.5	150.9
Total Accounts Receivable	278.5	250.2
TOTAL CURRENT ASSETS	520.1	446.9
Property, Plant and Equipment
Transmission	6,812.6	6,301.5
Other Property, Plant and Equipment	1,145.9	1,022.8
Construction Work in Progress	904.6	805.2
Total Property, Plant and Equipment	14,661.9	13,442.3
Accumulated Depreciation and Amortization	1,887.9	1,760.7
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	12,774.0	11,681.6
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS	696.6	763.7
TOTAL ASSETS	13,990.7	12,892.2
Current Liabilities
Accounts Payable	192.3	331.0
Accrued Taxes	99.1	95.5
TOTAL CURRENT LIABILITIES	749.4	1,043.8
Liabilities, Noncurrent
Regulatory Liabilities and Deferred Investment Tax Credits	1,261.4	1,259.6
TOTAL NONCURRENT LIABILITIES	8,445.2	7,944.1
TOTAL LIABILITIES	9,194.6	8,987.9
Equity [Abstract]
Retained Earnings	2,725.1	2,354.7
TOTAL LIABILITIES AND EQUITY	13,990.7	12,892.2
Operating Activites
Net Income (Loss)	370.4	307.9	289.8
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	468.5	452.4	387.0
Deferred Income Taxes	64.1	42.2	43.0
Allowance for Equity Funds Used During Construction	(28.4)	(19.7)	(21.5)
Change in Other Noncurrent Assets	(96.5)	(36.2)	(78.2)
Increase (Decrease) in Other Noncurrent Liabilities	24.3	57.6	26.4
Accounts Receivable, Net	(28.3)	(45.0)	(21.6)
Accounts Payable	(24.1)	25.0	8.9
Accrued Taxes, Net	11.8	14.8	7.0
Net Cash Flows from Operating Activities	659.7	731.9	596.6
Investing Activities
Net Cash Flows Used for Investing Activities	(1,408.0)	(1,269.9)	(1,000.8)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities	749.6	540.3	405.9
Cash and Cash Equivalents at Beginning of Period	0.1
Cash and Cash Equivalents at End of Period	0.1	0.1
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts	225.6	198.9	168.9
Income Taxes	11.5	11.0	5.7
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid	112.2	235.4	230.0
Construction Expenditures Included in Current Liabilities as of December 31,	112.2	235.4	230.0
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt	505.4	1,188.6	444.2
Repayments of Long-term Debt	278.5	716.0	88.7
Net Income (Loss)	370.4	307.9	289.8
Retained Earnings	2,725.1	2,354.7
AEP Texas Inc. [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)	370.4	307.9	289.8
Operating Activites
Net Income (Loss)	370.4	307.9	289.8
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)	$ 370.4	307.9	289.8
AEP Texas Inc. [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	30.00%
AEP Texas Inc. [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	54.00%
AEP Texas Inc. [Member] | Pension Plans [Member] | Other Investments [Member]
Target Asset Allocations
Target Asset Allocation	15.00%
AEP Texas Inc. [Member] | Pension Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
AEP Texas Inc. [Member] | Other Postretirement Benefit Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	58.00%
AEP Texas Inc. [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	41.00%
AEP Texas Inc. [Member] | Other Postretirement Benefit Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
AEP Texas Inc. [Member] | Pension and Other Postretirement Benefit Plans [Member]
Supplementary Information
Securities Loaned	$ 62.0	83.0
AEP Transmission Co [Member]
Materials and Supplies	0.0	10.7
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment	393.8	346.2	297.3
Amortization of Certain Securitized Assets	0.0	0.0	0.0
Amortization of Regulatory Assets and Liabilities	0.0	0.0	0.0
Total Depreciation and Amortization	393.8	346.2	297.3
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period	0.0	0.0	0.0
Revenues
TOTAL REVENUES	1,672.0	1,624.5	1,469.3
Expenses
Depreciation and Amortization	393.8	346.2	297.3
TOTAL EXPENSES	806.4	770.8	660.0
OPERATING INCOME (LOSS)	865.6	853.7	809.3
Other Income (Expense)
Allowance for Equity Funds Used During Construction	83.2	70.7	67.2
Interest Expense	(194.5)	(162.7)	(141.2)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)	761.3	763.3	735.8
Income Tax Expense (Benefit)	147.1	169.1	144.1
Net Income (Loss)	614.2	594.2	591.7
Accounts Receivable:
Customers	82.2	46.9
Total Accounts Receivable	207.7	166.4
TOTAL CURRENT ASSETS	278.8	188.7
Property, Plant and Equipment
Transmission	13,723.9	12,335.4
Other Property, Plant and Equipment	501.4	476.8
Construction Work in Progress	1,563.7	1,554.7
Total Property, Plant and Equipment	15,789.0	14,366.9
Accumulated Depreciation and Amortization	1,291.3	1,027.0
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	14,497.7	13,339.9
Other Noncurrent Assets
Deferred Property Taxes	286.4	266.6
TOTAL OTHER NONCURRENT ASSETS	296.0	285.6
TOTAL ASSETS	15,072.5	13,814.2
Current Liabilities
Accounts Payable	274.7	427.8
Accrued Taxes	568.6	529.8
TOTAL CURRENT LIABILITIES	1,286.1	1,368.0
Liabilities, Noncurrent
Regulatory Liabilities and Deferred Investment Tax Credits	783.7	723.3
TOTAL NONCURRENT LIABILITIES	7,453.1	6,573.2
TOTAL LIABILITIES	8,739.2	7,941.2
Equity [Abstract]
Retained Earnings	3,289.9	2,850.7
TOTAL MEMBER'S EQUITY	6,333.3	5,873.0	5,376.1	4,712.9
TOTAL LIABILITIES AND EQUITY	15,072.5	13,814.2
Operating Activites
Net Income (Loss)	614.2	594.2	591.7
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	393.8	346.2	297.3
Deferred Income Taxes	44.1	62.3	68.5
Allowance for Equity Funds Used During Construction	(83.2)	(70.7)	(67.2)
Amortization of Deferred Property Taxes	(19.8)	(20.9)	(25.6)
Change in Other Noncurrent Assets	8.6	(7.4)	7.5
Increase (Decrease) in Other Noncurrent Liabilities	134.2	68.7	3.7
Accounts Receivable, Net	(41.3)	(46.3)	(16.0)
Accounts Payable	22.8	18.5	(2.2)
Accrued Taxes, Net	42.9	50.2	67.2
Net Cash Flows from Operating Activities	1,137.6	995.3	925.7
Investing Activities
Net Cash Flows Used for Investing Activities	(1,557.7)	(1,439.2)	(1,359.0)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities	420.1	443.9	433.3
Cash and Cash Equivalents at Beginning of Period	0.0	0.0	0.0
Cash and Cash Equivalents at End of Period	0.0	0.0	0.0
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts	179.9	158.8	132.9
Income Taxes	87.6	95.5	65.7
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid	177.6	320.7	358.7
Construction Expenditures Included in Current Liabilities as of December 31,	177.6	320.7	358.7
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt	689.0	540.8	443.7
Repayments of Long-term Debt	60.0	104.0	50.0
Net Income (Loss)	614.2	594.2	591.7
Retained Earnings	3,289.9	2,850.7
AEP Transmission Co [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)	614.2	594.2	591.7
Equity [Abstract]
TOTAL MEMBER'S EQUITY	3,289.9	2,850.7	2,426.5	1,947.3
Operating Activites
Net Income (Loss)	614.2	594.2	591.7
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)	614.2	594.2	591.7
Appalachian Power Co [Member]
Materials and Supplies	148.4	130.6
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment	571.1	576.1	547.0
Amortization of Certain Securitized Assets	0.0	0.0	0.0
Amortization of Regulatory Assets and Liabilities	0.8	(0.2)	(0.8)
Total Depreciation and Amortization	571.9	575.9	546.2
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period	7.5
Restricted Cash	14.9	14.4
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	19.9	21.9	20.1	22.7
Revenues
TOTAL REVENUES	3,720.7	3,519.9	3,105.2
Expenses
Depreciation and Amortization	571.9	575.9	546.2
TOTAL EXPENSES	3,189.7	2,917.8	2,555.8
OPERATING INCOME (LOSS)	531.0	602.1	549.4
Other Income (Expense)
Allowance for Equity Funds Used During Construction	11.9	11.7	15.6
Interest Expense	(269.6)	(233.9)	(214.0)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)	308.6	412.4	371.0
Income Tax Expense (Benefit)	14.2	18.2	22.1
Net Income (Loss)	294.4	394.2	348.9
Accounts Receivable:
Customers	170.3	168.9
Total Accounts Receivable	338.5	352.8
TOTAL CURRENT ASSETS	1,059.0	1,259.6
Property, Plant and Equipment
Transmission	4,711.8	4,482.8
Other Property, Plant and Equipment	981.3	883.3
Construction Work in Progress	709.2	705.3
Total Property, Plant and Equipment	18,620.2	17,781.2
Accumulated Depreciation and Amortization	5,688.7	5,402.0
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	12,931.5	12,379.2
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS	1,721.4	1,583.4
TOTAL ASSETS	15,711.9	15,222.2
Current Liabilities
Accounts Payable	280.4	451.2
Accrued Taxes	117.6	101.0
TOTAL CURRENT LIABILITIES	1,685.9	1,390.2
Liabilities, Noncurrent
Regulatory Liabilities and Deferred Investment Tax Credits	1,081.9	1,143.6
TOTAL NONCURRENT LIABILITIES	8,749.3	8,856.6
TOTAL LIABILITIES	10,435.2	10,246.8
Equity [Abstract]
Retained Earnings	3,185.5	2,891.1
TOTAL LIABILITIES AND EQUITY	15,711.9	15,222.2
Operating Activites
Net Income (Loss)	294.4	394.2	348.9
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	571.9	575.9	546.2
Deferred Income Taxes	(54.3)	79.6	15.0
Allowance for Equity Funds Used During Construction	(11.9)	(11.7)	(15.6)
Change in Other Noncurrent Assets	(115.3)	(75.2)	(68.8)
Increase (Decrease) in Other Noncurrent Liabilities	(1.9)	31.4	35.6
Accounts Receivable, Net	17.5	(8.5)	(53.3)
Accounts Payable	(125.9)	190.1	36.8
Accrued Taxes, Net	25.2	6.7	(16.2)
Net Cash Flows from Operating Activities	723.1	601.2	611.7
Investing Activities
Net Cash Flows Used for Investing Activities	(1,054.9)	(1,005.2)	(826.5)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities	329.8	405.8	212.2
Cash and Cash Equivalents at Beginning of Period	7.5
Cash and Cash Equivalents at End of Period	5.0	7.5
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts	259.7	215.1	207.5
Income Taxes	47.4	(88.6)	32.8
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid	100.7	164.6	139.1
Construction Expenditures Included in Current Liabilities as of December 31,	100.7	164.6	139.1
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt	200.0	698.0	494.0
Repayments of Long-term Debt	26.6	230.4	393.0
Net Income (Loss)	294.4	394.2	348.9
Retained Earnings	3,185.5	2,891.1
Appalachian Power Co [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)	294.4	394.2	348.9
Operating Activites
Net Income (Loss)	294.4	394.2	348.9
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)	$ 294.4	394.2	348.9
Appalachian Power Co [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	30.00%
Appalachian Power Co [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	54.00%
Appalachian Power Co [Member] | Pension Plans [Member] | Other Investments [Member]
Target Asset Allocations
Target Asset Allocation	15.00%
Appalachian Power Co [Member] | Pension Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Appalachian Power Co [Member] | Other Postretirement Benefit Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	58.00%
Appalachian Power Co [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	41.00%
Appalachian Power Co [Member] | Other Postretirement Benefit Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Appalachian Power Co [Member] | Pension and Other Postretirement Benefit Plans [Member]
Supplementary Information
Securities Loaned	$ 62.0	83.0
Indiana Michigan Power Co [Member]
Materials and Supplies	208.2	188.1
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment	439.8	511.9	424.9
Amortization of Certain Securitized Assets	0.0	0.0	0.0
Amortization of Regulatory Assets and Liabilities	30.2	15.3	21.1
Total Depreciation and Amortization	470.0	527.2	446.0
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period	4.2	1.3	3.3
Revenues
TOTAL REVENUES	2,535.9	2,669.6	2,326.7
Expenses
Depreciation and Amortization	470.0	527.2	446.0
TOTAL EXPENSES	2,048.2	2,249.7	1,968.8
OPERATING INCOME (LOSS)	487.7	419.9	357.9
Other Income (Expense)
Allowance for Equity Funds Used During Construction	10.9	9.8	12.8
Interest Expense	(136.7)	(125.2)	(116.8)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)	394.5	328.9	269.2
Income Tax Expense (Benefit)	58.6	4.2	(10.6)
Net Income (Loss)	335.9	324.7	279.8
Accounts Receivable:
Customers	66.9	96.6
Total Accounts Receivable	140.3	205.8
TOTAL CURRENT ASSETS	528.0	571.8
Property, Plant and Equipment
Transmission	1,906.4	1,842.2
Other Property, Plant and Equipment	898.5	839.3
Construction Work in Progress	301.7	253.0
Total Property, Plant and Equipment	12,007.4	11,544.3
Accumulated Depreciation and Amortization	4,378.4	4,132.8
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	7,629.0	7,411.5
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS	4,651.0	4,135.6
TOTAL ASSETS	12,808.0	12,118.9
Current Liabilities
Accounts Payable	225.8	173.4
Accrued Taxes	104.7	103.2
TOTAL CURRENT LIABILITIES	830.2	1,197.1
Liabilities, Noncurrent
Regulatory Liabilities and Deferred Investment Tax Credits	2,052.3	1,702.2
TOTAL NONCURRENT LIABILITIES	8,837.6	7,913.5
TOTAL LIABILITIES	9,667.8	9,110.6
Equity [Abstract]
Retained Earnings	2,086.6	1,963.2
TOTAL LIABILITIES AND EQUITY	12,808.0	12,118.9
Operating Activites
Net Income (Loss)	335.9	324.7	279.8
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	470.0	527.2	446.0
Deferred Income Taxes	(54.1)	(45.1)	(38.0)
Allowance for Equity Funds Used During Construction	(10.9)	(9.8)	(12.8)
Change in Other Noncurrent Assets	(80.3)	(47.3)	(54.1)
Increase (Decrease) in Other Noncurrent Liabilities	47.6	62.4	7.5
Accounts Receivable, Net	71.4	(82.7)	(22.3)
Accounts Payable	22.5	37.3	42.3
Accrued Taxes, Net	1.5	9.4	1.6
Net Cash Flows from Operating Activities	879.9	720.7	733.7
Investing Activities
Net Cash Flows Used for Investing Activities	(707.0)	(701.5)	(633.1)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities	(175.0)	(16.3)	(102.6)
Cash and Cash Equivalents at Beginning of Period	4.2	1.3	3.3
Cash and Cash Equivalents at End of Period	2.1	4.2	1.3
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts	131.6	120.9	110.9
Income Taxes	109.0	10.1	29.3
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid	67.8	71.9	87.8
Construction Expenditures Included in Current Liabilities as of December 31,	67.8	71.9	87.8
Acquisition of Nuclear Fuel Included in Current Liabilities as of December 31,	24.2	0.0	0.0
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt	565.3	142.7	546.7
Repayments of Long-term Debt	343.3	83.4	383.5
Net Income (Loss)	335.9	324.7	279.8
Retained Earnings	2,086.6	1,963.2
Indiana Michigan Power Co [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)	335.9	324.7	279.8
Operating Activites
Net Income (Loss)	335.9	324.7	279.8
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)	$ 335.9	324.7	279.8
Indiana Michigan Power Co [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	30.00%
Indiana Michigan Power Co [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	54.00%
Indiana Michigan Power Co [Member] | Pension Plans [Member] | Other Investments [Member]
Target Asset Allocations
Target Asset Allocation	15.00%
Indiana Michigan Power Co [Member] | Pension Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Indiana Michigan Power Co [Member] | Other Postretirement Benefit Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	58.00%
Indiana Michigan Power Co [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	41.00%
Indiana Michigan Power Co [Member] | Other Postretirement Benefit Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Indiana Michigan Power Co [Member] | Pension and Other Postretirement Benefit Plans [Member]
Supplementary Information
Securities Loaned	$ 62.0	83.0
Ohio Power Co [Member]
Materials and Supplies	175.0	109.5
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment	315.8	293.1	301.1
Amortization of Certain Securitized Assets	0.0	0.0	0.0
Amortization of Regulatory Assets and Liabilities	0.4	1.2	2.2
Total Depreciation and Amortization	316.2	294.3	303.3
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period	9.6
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	6.4	9.6	3.0	$ 7.4
Revenues
TOTAL REVENUES	3,811.4	3,665.1	2,899.1
Expenses
Depreciation and Amortization	316.2	294.3	303.3
TOTAL EXPENSES	3,341.5	3,251.4	2,513.9
OPERATING INCOME (LOSS)	469.9	413.7	385.2
Other Income (Expense)
Allowance for Equity Funds Used During Construction	17.1	13.9	10.8
Interest Expense	(130.9)	(119.6)	(124.4)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)	382.5	331.4	288.0
Income Tax Expense (Benefit)	54.3	44.2	34.4
Net Income (Loss)	328.2	287.8	253.6
Accounts Receivable:
Customers	39.2	119.9
Total Accounts Receivable	170.7	238.6
TOTAL CURRENT ASSETS	377.8	414.4
Property, Plant and Equipment
Transmission	3,395.1	3,198.6
Other Property, Plant and Equipment	1,125.0	1,051.4
Construction Work in Progress	654.0	474.3
Total Property, Plant and Equipment	12,013.5	11,174.6
Accumulated Depreciation and Amortization	2,713.6	2,565.3
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	9,299.9	8,609.3
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS	1,166.0	979.4
TOTAL ASSETS	10,843.7	10,003.1
Current Liabilities
Accounts Payable	320.7	337.3
Accrued Taxes	763.3	733.1
TOTAL CURRENT LIABILITIES	1,614.3	1,635.5
Liabilities, Noncurrent
Regulatory Liabilities and Deferred Investment Tax Credits	1,003.6	1,044.0
TOTAL NONCURRENT LIABILITIES	5,658.1	5,279.5
TOTAL LIABILITIES	7,272.4	6,915.0
Equity [Abstract]
Retained Earnings	2,237.3	1,929.1
TOTAL LIABILITIES AND EQUITY	10,843.7	10,003.1
Operating Activites
Net Income (Loss)	328.2	287.8	253.6
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	316.2	294.3	303.3
Deferred Income Taxes	7.9	71.5	30.7
Allowance for Equity Funds Used During Construction	(17.1)	(13.9)	(10.8)
Amortization of Deferred Property Taxes	(11.5)	(20.0)	(35.3)
Change in Other Noncurrent Assets	(137.5)	(87.1)	(40.7)
Increase (Decrease) in Other Noncurrent Liabilities	(0.4)	91.1	6.9
Accounts Receivable, Net	72.8	(83.7)	(11.8)
Accounts Payable	23.6	112.7	19.1
Accrued Taxes, Net	27.5	27.8	78.2
Net Cash Flows from Operating Activities	462.3	686.1	575.6
Investing Activities
Net Cash Flows Used for Investing Activities	(949.4)	(802.5)	(753.3)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities	483.9	123.0	173.3
Cash and Cash Equivalents at Beginning of Period	9.6
Cash and Cash Equivalents at End of Period	6.4	9.6
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts	124.1	113.4	119.5
Income Taxes	38.9	(19.7)	(7.9)
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid	97.7	109.7	97.1
Construction Expenditures Included in Current Liabilities as of December 31,	97.7	109.7	97.1
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt	395.0	0.0	1,037.1
Repayments of Long-term Debt	0.6	0.1	500.1
Income (Loss) from Equity Method Investment	0.0	0.6	0.0
Net Income (Loss)	328.2	287.8	253.6
Retained Earnings	2,237.3	1,929.1
Ohio Power Co [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)	328.2	287.8	253.6
Operating Activites
Net Income (Loss)	328.2	287.8	253.6
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)	$ 328.2	287.8	253.6
Ohio Power Co [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	30.00%
Ohio Power Co [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	54.00%
Ohio Power Co [Member] | Pension Plans [Member] | Other Investments [Member]
Target Asset Allocations
Target Asset Allocation	15.00%
Ohio Power Co [Member] | Pension Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Ohio Power Co [Member] | Other Postretirement Benefit Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	58.00%
Ohio Power Co [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	41.00%
Ohio Power Co [Member] | Other Postretirement Benefit Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Ohio Power Co [Member] | Pension and Other Postretirement Benefit Plans [Member]
Supplementary Information
Securities Loaned	$ 62.0	83.0
Public Service Co Of Oklahoma [Member]
Materials and Supplies	106.9	111.1
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment	240.3	226.2	185.9
Amortization of Certain Securitized Assets	0.0	0.0	0.0
Amortization of Regulatory Assets and Liabilities	15.2	3.9	10.7
Total Depreciation and Amortization	255.5	230.1	196.6
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period	4.0	1.3	2.6
Revenues
TOTAL REVENUES	1,977.0	1,874.7	1,474.4
Expenses
Depreciation and Amortization	255.5	230.1	196.6
TOTAL EXPENSES	1,742.7	1,693.9	1,281.5
OPERATING INCOME (LOSS)	234.3	180.8	192.9
Other Income (Expense)
Allowance for Equity Funds Used During Construction	8.4	1.5	2.4
Interest Expense	(103.6)	(83.8)	(62.9)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)	155.2	118.4	145.2
Income Tax Expense (Benefit)	(53.6)	(49.2)	4.1
Net Income (Loss)	208.8	167.6	141.1
Accounts Receivable:
Customers	107.6	70.1
Total Accounts Receivable	139.4	123.1
Accrued Tax Benefits	31.0	16.1
TOTAL CURRENT ASSETS	469.5	491.5
Property, Plant and Equipment
Transmission	1,228.3	1,164.4
Other Property, Plant and Equipment	505.9	469.3
Construction Work in Progress	313.7	219.3
Total Property, Plant and Equipment	8,194.2	7,464.2
Accumulated Depreciation and Amortization	2,081.9	1,837.7
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	6,112.3	5,626.5
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS	753.1	847.9
TOTAL ASSETS	7,334.9	6,965.9
Current Liabilities
Accounts Payable	159.3	202.9
Accrued Taxes	30.7	28.7
TOTAL CURRENT LIABILITIES	559.0	842.7
Liabilities, Noncurrent
Regulatory Liabilities and Deferred Investment Tax Credits	765.6	809.1
TOTAL NONCURRENT LIABILITIES	4,205.3	3,704.1
TOTAL LIABILITIES	4,764.3	4,546.8
Equity [Abstract]
Retained Earnings	1,374.3	1,218.0
TOTAL LIABILITIES AND EQUITY	7,334.9	6,965.9
Operating Activites
Net Income (Loss)	208.8	167.6	141.1
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	255.5	230.1	196.6
Deferred Income Taxes	7.9	(59.4)	113.9
Allowance for Equity Funds Used During Construction	(8.4)	(1.5)	(2.4)
Change in Other Noncurrent Assets	(71.3)	(40.1)	(14.8)
Increase (Decrease) in Other Noncurrent Liabilities	8.2	29.9	4.4
Accounts Receivable, Net	(16.3)	(46.0)	(28.7)
Accounts Payable	(58.2)	57.5	34.2
Accrued Taxes, Net	(12.9)	3.2	(6.5)
Net Cash Flows from Operating Activities	590.5	747.7	(433.3)
Investing Activities
Net Cash Flows Used for Investing Activities	(692.8)	(992.0)	(626.7)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities	100.8	247.0	1,058.7
Cash and Cash Equivalents at Beginning of Period	4.0	1.3	2.6
Cash and Cash Equivalents at End of Period	2.5	4.0	1.3
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts	87.3	79.7	57.0
Income Taxes	(10.6)	(12.5)	(102.9)
Cash Received from the Sale of Transferable Tax Credits	(34.6)	0.0	0.0
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid	72.9	69.8	56.8
Construction Expenditures Included in Current Liabilities as of December 31,	72.9	69.8	56.8
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt	469.8	499.7	1,290.0
Repayments of Long-term Debt	0.5	500.5	750.5
Net Income (Loss)	208.8	167.6	141.1
Retained Earnings	1,374.3	1,218.0
Public Service Co Of Oklahoma [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)	208.8	167.6	141.1
Operating Activites
Net Income (Loss)	208.8	167.6	141.1
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)	$ 208.8	167.6	141.1
Public Service Co Of Oklahoma [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	30.00%
Public Service Co Of Oklahoma [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	54.00%
Public Service Co Of Oklahoma [Member] | Pension Plans [Member] | Other Investments [Member]
Target Asset Allocations
Target Asset Allocation	15.00%
Public Service Co Of Oklahoma [Member] | Pension Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Public Service Co Of Oklahoma [Member] | Other Postretirement Benefit Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	58.00%
Public Service Co Of Oklahoma [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	41.00%
Public Service Co Of Oklahoma [Member] | Other Postretirement Benefit Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Public Service Co Of Oklahoma [Member] | Pension and Other Postretirement Benefit Plans [Member]
Supplementary Information
Securities Loaned	$ 62.0	83.0
Southwestern Electric Power Co [Member]
Materials and Supplies	88.4	92.1
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment	323.4	319.3	292.9
Amortization of Certain Securitized Assets	0.0	0.0	0.0
Amortization of Regulatory Assets and Liabilities	19.4	5.5	2.1
Total Depreciation and Amortization	342.8	324.8	295.0
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period	88.4	51.2	13.2
Amounts Attributable to AEP Common Shareholders
Net Income (Loss) Attributable to Noncontrolling Interests	3.5	4.2	3.1
Net Income (Loss)	220.3	290.1	239.0
Revenues
TOTAL REVENUES	2,182.8	2,284.4	2,131.8
Expenses
Depreciation and Amortization	342.8	324.8	295.0
TOTAL EXPENSES	1,890.5	1,914.4	1,792.3
OPERATING INCOME (LOSS)	292.3	370.0	339.5
Other Income (Expense)
Allowance for Equity Funds Used During Construction	11.5	4.9	7.0
Interest Expense	(147.2)	(137.4)	(125.9)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)	189.1	267.7	238.1
Income Tax Expense (Benefit)	(33.3)	(25.2)	(0.6)
Net Income (Loss)	223.8	294.3	242.1
Accounts Receivable:
Customers	39.0	38.8
Total Accounts Receivable	94.5	114.6
Accrued Tax Benefits	28.4	16.5
TOTAL CURRENT ASSETS	541.3	812.2
Property, Plant and Equipment
Transmission	2,660.6	2,479.8
Other Property, Plant and Equipment	814.4	804.4
Construction Work in Progress	555.8	369.5
Total Property, Plant and Equipment	11,645.6	11,789.5
Accumulated Depreciation and Amortization	3,087.2	3,527.3
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	8,558.4	8,262.2
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS	1,457.9	1,304.4
TOTAL ASSETS	10,557.6	10,378.8
Current Liabilities
Accounts Payable	198.9	213.1
Accrued Taxes	58.7	52.8
TOTAL CURRENT LIABILITIES	686.9	947.7
Liabilities, Noncurrent
Regulatory Liabilities and Deferred Investment Tax Credits	756.1	825.7
TOTAL NONCURRENT LIABILITIES	6,100.3	5,756.3
TOTAL LIABILITIES	6,787.2	6,704.0
Equity [Abstract]
Retained Earnings	2,281.3	2,236.0
TOTAL LIABILITIES AND EQUITY	10,557.6	10,378.8
Operating Activites
Net Income (Loss)	223.8	294.3	242.1
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization	342.8	324.8	295.0
Deferred Income Taxes	54.0	9.4	16.6
Allowance for Equity Funds Used During Construction	(11.5)	(4.9)	(7.0)
Change in Other Noncurrent Assets	(40.5)	42.9	41.9
Increase (Decrease) in Other Noncurrent Liabilities	11.0	18.3	(1.1)
Accounts Receivable, Net	20.1	(28.2)	(21.5)
Accounts Payable	(8.4)	34.1	22.0
Accrued Taxes, Net	(4.5)	9.8	15.4
Net Cash Flows from Operating Activities	803.0	586.6	96.8
Investing Activities
Net Cash Flows Used for Investing Activities	(776.7)	(1,085.1)	(920.7)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities	(112.3)	535.7	861.9
Cash and Cash Equivalents at Beginning of Period	88.4	51.2	13.2
Cash and Cash Equivalents at End of Period	2.4	88.4	51.2
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts	128.9	131.2	116.5
Income Taxes	(41.0)	(29.1)	(28.8)
Cash Received from the Sale of Transferable Tax Credits	(41.4)	0.0	0.0
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid	63.7	105.6	69.0
Construction Expenditures Included in Current Liabilities as of December 31,	63.7	105.6	69.0
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt	346.8	0.0	1,137.6
Repayments of Long-term Debt	94.1	6.2	381.2
Income (Loss) from Equity Method Investment	1.4	1.4	3.4
Net Income (Loss)	223.8	294.3	242.1
Retained Earnings	2,281.3	2,236.0
Southwestern Electric Power Co [Member] | Retained Earnings [Member]
Amounts Attributable to AEP Common Shareholders
Net Income (Loss)	$ 220.3	290.1	$ 239.0
Southwestern Electric Power Co [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	30.00%
Southwestern Electric Power Co [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	54.00%
Southwestern Electric Power Co [Member] | Pension Plans [Member] | Other Investments [Member]
Target Asset Allocations
Target Asset Allocation	15.00%
Southwestern Electric Power Co [Member] | Pension Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Southwestern Electric Power Co [Member] | Other Postretirement Benefit Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation	58.00%
Southwestern Electric Power Co [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation	41.00%
Southwestern Electric Power Co [Member] | Other Postretirement Benefit Plans [Member] | Cash and Cash Equivalents [Member]
Target Asset Allocations
Target Asset Allocation	1.00%
Southwestern Electric Power Co [Member] | Pension and Other Postretirement Benefit Plans [Member]
Supplementary Information
Securities Loaned	$ 62.0	$ 83.0
Restricted Stock Units and Performance Share Units [Member]
Weighted Average Dilutive Effect of:
Weighted Average Dilutive Effect of Shares	1,300,000	1,700,000	1,300,000
Dilutive Securities, Effect on Basic Earnings Per Share	$ (0.02)	$ (0.02)	$ (0.01)
Revenues [Member] | AEP Texas Inc. [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	41.00%	45.00%	43.00%
Revenues [Member] | AEP Transmission Co [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	79.00%	79.00%	79.00%
Revenues [Member] | Appalachian Power Co [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	10.00%	10.00%	10.00%
Revenues [Member] | Indiana Michigan Power Co [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	10.00%	10.00%	10.00%
Revenues [Member] | Ohio Power Co [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	10.00%	10.00%	10.00%
Revenues [Member] | Public Service Co Of Oklahoma [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	10.00%	10.00%	10.00%
Revenues [Member] | Southwestern Electric Power Co [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	10.00%	10.00%	10.00%
Accounts Receivable [Member] | AEP Texas Inc. [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	34.00%	42.00%	41.00%
Accounts Receivable [Member] | AEP Transmission Co [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	60.00%	72.00%	81.00%
Noncontrolling Interest [Member] | Dry Lake Solar Project [Member]
Noncash Investing and Financing Activities:
Noncash Contribution of Assets by Noncontrolling Interest	$ 0.0	$ 0.0	$ 35.3
Sabine Mining Co [Member] | Southwestern Electric Power Co [Member]
Materials and Supplies	3.9	4.2
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period	84.2
Property, Plant and Equipment
Other Property, Plant and Equipment	182.7	219.8
Accumulated Depreciation and Amortization	182.7	212.5
Net Cash Provided by (Used in) Financing Activities
Cash and Cash Equivalents at Beginning of Period	84.2
Cash and Cash Equivalents at End of Period	$ 0.0	$ 84.2