Organization and Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Materials and Supplies		$ 681.3		$ 680.6
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment		2,717.1		2,487.5	$ 2,203.7
Amortization of Certain Securitized Assets		64.2		171.3	280.7
Amortization of Regulatory Assets and Liabilities		44.4		24.0	30.1
Total Depreciation and Amortization		2,825.7		2,682.8	2,514.5
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period		392.7
Restricted Cash		48.0		45.6
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		451.4		438.3	432.6	$ 444.1
Amounts Attributable to AEP Common Shareholders
Net Income (Loss) Attributable to Noncontrolling Interests		0.0		(3.4)	(1.3)
Net Income (Loss)		$ 2,488.1		$ 2,200.1	$ 1,921.1
Weighted Average Number of Basic AEP Common Shares Outstanding		500,522,177		495,718,223	493,694,345
Earnings Per Share, Basic		$ 4.97		$ 4.44	$ 3.89
Weighted Average Dilutive Effect of:
Weighted Average Number of Diluted AEP Common Shares Outstanding		501,784,032		497,226,867	495,306,238
Earnings Per Share, Diluted		$ 4.96		$ 4.42	$ 3.88
Revenues
TOTAL REVENUES		$ 16,792.0		$ 14,918.5	$ 15,561.4
Expenses
Depreciation and Amortization		2,825.7		2,682.8	2,514.5
TOTAL EXPENSES		13,380.7		11,930.8	12,969.1
OPERATING INCOME (LOSS)		3,411.3		2,987.7	2,592.3
Other Income (Expense)
Allowance for Equity Funds Used During Construction		139.7		148.1	168.4
Interest Expense		(1,199.1)		(1,165.7)	(1,072.5)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)		2,511.9		2,146.1	1,834.8
Income Tax Expense (Benefit)		115.5		40.5	(12.9)
Net Income (Loss)		2,488.1		2,196.7	1,919.8
Accounts Receivable:
Customers		720.9		613.6
Total Accounts Receivable		1,941.6		1,842.7
Accrued Tax Benefits		121.5		185.3
TOTAL CURRENT ASSETS		7,809.2		4,351.5
Property, Plant and Equipment
Transmission		29,911.1		27,886.7
Other Property, Plant and Equipment		5,682.9		5,294.6
Construction Work in Progress		3,684.3		4,025.7
Total Property, Plant and Equipment		86,806.4		84,313.0
Accumulated Depreciation and Amortization		20,805.1		20,411.4
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		66,001.3	[1]	63,901.6
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS		13,858.2		12,504.1
TOTAL ASSETS		87,668.7	[2]	80,757.2	75,892.3
Current Liabilities
Accounts Payable		2,054.6		1,709.7
Accrued Taxes		1,586.4		1,476.4
TOTAL CURRENT LIABILITIES		12,426.7		9,926.7
Liabilities, Noncurrent
Deferred Income Taxes		8,202.5		8,240.9
Regulatory Liabilities and Deferred Investment Tax Credits		8,686.3	[3]	8,378.7
TOTAL NONCURRENT LIABILITIES		52,518.5		50,010.8
TOTAL LIABILITIES		64,945.2		59,937.5
Equity [Abstract]
Retained Earnings		11,667.1		10,687.8
TOTAL LIABILITIES AND EQUITY		87,668.7		80,757.2
Operating Activites
Net Income (Loss)		2,488.1		2,196.7	1,919.8
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization		2,825.7		2,682.8	2,514.5
Deferred Income Taxes		107.6		196.1	(17.8)
Allowance for Equity Funds Used During Construction		(139.7)		(148.1)	(168.4)
Amortization of Deferred Property Taxes		(68.0)		(43.3)	(73.8)
Change in Other Noncurrent Assets		(132.7)		(142.5)	(112.8)
Increase (Decrease) in Other Noncurrent Liabilities		206.4		(54.5)	(116.1)
Accounts Receivable, Net		(119.7)		(129.3)	247.8
Accounts Payable		200.6		(35.3)	5.8
Accrued Taxes, Net		218.7		20.1	138.9
Net Cash Flows from Operating Activities		3,839.9		3,832.9	4,270.1
Investing Activities
Net Cash Flows Used for Investing Activities		(6,433.9)		(6,233.9)	(7,144.5)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities		2,607.1		2,406.7	2,862.9
Cash and Cash Equivalents at Beginning of Period		392.7
Cash and Cash Equivalents at End of Period		403.4		392.7
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts		1,137.2		1,029.1	1,022.5
Income Taxes		13.2		(49.1)	6.1
Noncash Investing and Financing Activities:
Noncash Acquisition Under Finance Leases		287.6		44.2	87.5
Construction in Progress Expenditures Incurred but Not yet Paid		1,180.4		975.4	1,341.1
Construction Expenditures Included in Current Liabilities as of December 31,		1,180.4		975.4	1,341.1
Construction Expenditures Included in Noncurrent Liabilities as of December 31,		0.0		5.5	0.0
Acquisition of Nuclear Fuel Included in Current Liabilities as of December 31,		0.0		33.4	0.1
Expected Reimbursement For Spent Nuclear Fuel Dry Cask Storage		1.7		2.6	0.3
Forward Equity Purchase Contracts Included in Current and Noncurrent Liabilities as of December 31,		47.8		(86.2)	(7.6)
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt		6,486.3		5,626.1	4,536.6
Repayments of Long-term Debt		2,989.3		1,339.8	1,220.8
Equity Method Investment		1,447.5		1,406.3	1,356.6
Income (Loss) from Equity Method Investment		$ 91.7		$ 91.1	$ 72.1
Antidilutive Shares Outstanding		0		128,000	0
Net Income (Loss)		$ 2,488.1		$ 2,196.7	$ 1,919.8
Retained Earnings		11,667.1		10,687.8
2020 Equity Units [Member]
Noncash Investing and Financing Activities:
Forward Equity Purchase Contracts Included in Current and Noncurrent Liabilities as of December 31,		0.0		110.6
2019 Equity Units [Member]
Noncash Investing and Financing Activities:
Forward Equity Purchase Contracts Included in Current and Noncurrent Liabilities as of December 31,					47.3
Cedar Creek Project
Noncash Investing and Financing Activities:
Noncash Contribution of Assets to Cedar Creek Project		(9.3)		0.0	0.0
Sempra Renewable LLC and Santa Rita
Noncash Investing and Financing Activities:
Liabilities Assumed with Sempra Renewable LLC and Santa Rita East Acquisition		0.0		0.0	32.4
Retained Earnings [Member]
Amounts Attributable to AEP Common Shareholders
Net Income (Loss)		2,488.1		2,200.1	1,921.1
Noncash Investing and Financing Activities:
Forward Equity Purchase Contracts Included in Current and Noncurrent Liabilities as of December 31,		$ (1.1)
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		25.00%
Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		59.00%
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		59.00%
Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		40.00%
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		$ 137.0		177.0
AEP Texas Inc. [Member]
Materials and Supplies		73.9		70.0
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment		327.2		364.2	365.9
Amortization of Certain Securitized Assets		64.2		171.3	258.7
Amortization of Regulatory Assets and Liabilities		(4.4)		(5.7)	(2.3)
Total Depreciation and Amortization		387.0		529.8	622.3
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period		0.1
Restricted Cash		30.4		28.7
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		30.5		28.8	157.8	159.8
Revenues
TOTAL REVENUES		1,593.8		1,618.9	1,709.3
Expenses
Depreciation and Amortization		387.0		529.8	622.3
TOTAL EXPENSES		1,117.8		1,249.3	1,477.3
OPERATING INCOME (LOSS)		476.0		369.6	232.0
Other Income (Expense)
Allowance for Equity Funds Used During Construction		21.5		19.4	15.2
Interest Expense		(176.5)		(171.8)	(137.2)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)		332.9		229.8	124.7
Income Tax Expense (Benefit)		43.1		(11.2)	(53.6)
Net Income (Loss)		289.8		241.0	178.3
Accounts Receivable:
Customers		123.4		112.8
Total Accounts Receivable		205.2		183.6
Accrued Tax Benefits		24.8		16.8
TOTAL CURRENT ASSETS		347.2		310.9
Property, Plant and Equipment
Transmission		5,849.9		5,279.6
Other Property, Plant and Equipment		961.1		868.4
Construction Work in Progress		551.3		614.1
Total Property, Plant and Equipment		12,279.5		11,342.9
Accumulated Depreciation and Amortization		1,644.1		1,529.3
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		10,635.4		9,813.6
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS		854.1		905.7
TOTAL ASSETS		11,836.7		11,030.2
Current Liabilities
Accounts Payable		306.3		231.7
Affiliated Companies		32.5		44.0
Accrued Taxes		93.3		78.3
TOTAL CURRENT LIABILITIES		1,311.7		676.8
Liabilities, Noncurrent
Deferred Income Taxes		1,088.9		1,016.7
Regulatory Liabilities and Deferred Investment Tax Credits		1,242.0		1,270.8
TOTAL NONCURRENT LIABILITIES		6,930.8		7,147.4
TOTAL LIABILITIES		8,242.5		7,824.2
Equity [Abstract]
Retained Earnings		2,046.8		1,757.0
TOTAL LIABILITIES AND EQUITY		11,836.7		11,030.2
Operating Activites
Net Income (Loss)		289.8		241.0	178.3
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization		387.0		529.8	622.3
Deferred Income Taxes		43.0		(15.2)	(23.5)
Allowance for Equity Funds Used During Construction		(21.5)		(19.4)	(15.2)
Change in Other Noncurrent Assets		(78.2)		(74.0)	9.3
Increase (Decrease) in Other Noncurrent Liabilities		26.4		(24.7)	11.3
Accounts Receivable, Net		(21.6)		9.8	3.5
Accounts Payable		8.9		30.2	7.5
Accrued Taxes, Net		7.0		42.7	(11.8)
Net Cash Flows from Operating Activities		596.6		614.2	823.4
Investing Activities
Net Cash Flows Used for Investing Activities		(1,000.8)		(1,065.4)	(1,472.2)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities		405.9		322.2	646.8
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		168.9		153.2	148.6
Income Taxes		5.7		(42.9)	(11.0)
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid		230.0		177.8	225.5
Construction Expenditures Included in Current Liabilities as of December 31,		230.0		177.8	225.5
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt		444.2		652.7	1,070.4
Repayments of Long-term Debt		88.7		392.1	401.8
Net Income (Loss)		289.8		241.0	178.3
Retained Earnings		2,046.8		1,757.0
AEP Texas Inc. [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)		289.8		241.0	178.3
Operating Activites
Net Income (Loss)		289.8		241.0	178.3
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)		$ 289.8		241.0	178.3
AEP Texas Inc. [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation		25.00%
AEP Texas Inc. [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		59.00%
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		59.00%
AEP Texas Inc. [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		40.00%
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		$ 137.0		177.0
AEP Transmission Co [Member]
Materials and Supplies		9.3		8.5
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment		297.3		249.0	176.0
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		297.3		249.0	176.0
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period		0.0		0.0	0.0
Revenues
TOTAL REVENUES		1,469.3		1,145.7	1,021.4
Expenses
Depreciation and Amortization		297.3		249.0	176.0
TOTAL EXPENSES		660.0		564.2	454.2
OPERATING INCOME (LOSS)		809.3		581.5	567.2
Other Income (Expense)
Allowance for Equity Funds Used During Construction		67.2		74.0	84.3
Interest Expense		(141.2)		(127.8)	(97.4)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)		735.8		530.1	557.1
Income Tax Expense (Benefit)		144.1		106.7	117.4
Net Income (Loss)		591.7		423.4	439.7
Accounts Receivable:
Customers		22.5		22.9
Total Accounts Receivable		118.6		104.1
Accrued Tax Benefits		5.6		9.9
TOTAL CURRENT ASSETS		331.3		235.8
Property, Plant and Equipment
Transmission		10,886.3		9,593.5
Other Property, Plant and Equipment		427.4		329.5
Construction Work in Progress		1,394.8		1,422.6
Total Property, Plant and Equipment		12,708.5		11,345.6
Accumulated Depreciation and Amortization		772.8		572.8
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		11,935.7	[1]	10,772.8
Other Noncurrent Assets
Deferred Property Taxes		245.7		220.1
TOTAL OTHER NONCURRENT ASSETS		257.4		237.4
TOTAL ASSETS		12,524.4	[4]	11,246.0	9,890.8
Current Liabilities
Accounts Payable		460.1		380.4
Affiliated Companies		69.9		97.3
Accrued Taxes		479.0		418.1
TOTAL CURRENT LIABILITIES		1,296.9		1,137.5
Liabilities, Noncurrent
Deferred Income Taxes		962.9		906.9
Regulatory Liabilities and Deferred Investment Tax Credits		644.1	[5]	581.8
TOTAL NONCURRENT LIABILITIES		5,851.4		5,395.6
TOTAL LIABILITIES		7,148.3		6,533.1
Equity [Abstract]
Retained Earnings		2,426.5		1,947.3
TOTAL MEMBER'S EQUITY		5,376.1		4,712.9	4,009.5	3,569.8
TOTAL LIABILITIES AND EQUITY		12,524.4		11,246.0
Operating Activites
Net Income (Loss)		591.7		423.4	439.7
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization		297.3		249.0	176.0
Deferred Income Taxes		68.5		81.6	91.3
Allowance for Equity Funds Used During Construction		(67.2)		(74.0)	(84.3)
Amortization of Deferred Property Taxes		(25.6)		(26.6)	(35.6)
Change in Other Noncurrent Assets		7.5		(8.2)	9.6
Increase (Decrease) in Other Noncurrent Liabilities		3.7		8.3	(8.1)
Accounts Receivable, Net		(16.0)		(19.0)	(5.4)
Accounts Payable		(2.2)		77.8	37.6
Accrued Taxes, Net		67.2		62.7	90.8
Net Cash Flows from Operating Activities		925.7		771.2	708.6
Investing Activities
Net Cash Flows Used for Investing Activities		(1,359.0)		(1,640.4)	(1,403.2)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities		433.3		869.2	694.6
Net Increase (Decrease) in Cash and Cash Equivalents		0.0		0.0	0.0
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		132.9		119.7	90.6
Income Taxes		65.7		22.9	1.5
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid		358.7		311.9	472.7
Construction Expenditures Included in Current Liabilities as of December 31,		358.7		311.9	472.7
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt		443.7		519.5	688.0
Repayments of Long-term Debt		50.0		0.0	85.0
Net Income (Loss)		591.7		423.4	439.7
Retained Earnings		2,426.5		1,947.3
AEP Transmission Co [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)		591.7		423.4	439.7
Equity [Abstract]
TOTAL MEMBER'S EQUITY		2,426.5		1,947.3	1,528.9	1,089.2
Operating Activites
Net Income (Loss)		591.7		423.4	439.7
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)		591.7		423.4	439.7
Appalachian Power Co [Member]
Materials and Supplies		109.8		99.6
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment		547.0		507.8	466.5
Amortization of Certain Securitized Assets		0.0		0.0	0.0
Amortization of Regulatory Assets and Liabilities		(0.8)		(0.3)	0.3
Total Depreciation and Amortization		546.2		507.5	466.8
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period		5.8
Restricted Cash		17.6		16.9
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		20.1		22.7	26.8	29.8
Revenues
TOTAL REVENUES		3,105.2		2,796.2	2,924.7
Expenses
Depreciation and Amortization		546.2		507.5	466.8
TOTAL EXPENSES		2,555.8		2,239.6	2,527.4
OPERATING INCOME (LOSS)		549.4		556.6	397.3
Other Income (Expense)
Allowance for Equity Funds Used During Construction		15.6		14.6	16.6
Interest Expense		(214.0)		(217.6)	(205.0)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)		371.0		374.0	228.3
Income Tax Expense (Benefit)		22.1		4.3	(78.0)
Net Income (Loss)		348.9		369.7	306.3
Accounts Receivable:
Customers		158.5		142.8
Total Accounts Receivable		341.0		284.4
TOTAL CURRENT ASSETS		925.3		674.1
Property, Plant and Equipment
Transmission		4,322.4		3,900.5
Other Property, Plant and Equipment		696.6		627.2
Construction Work in Progress		469.9		484.6
Total Property, Plant and Equipment		16,856.1		16,110.3
Accumulated Depreciation and Amortization		5,051.8		4,716.2
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		11,804.3		11,394.1
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS		1,359.3		1,247.0
TOTAL ASSETS		14,088.9		13,315.2
Current Liabilities
Accounts Payable		262.2		212.0
Affiliated Companies		118.6		97.1
Accrued Taxes		119.7		109.9
TOTAL CURRENT LIABILITIES		1,415.9		1,217.7
Liabilities, Noncurrent
Deferred Income Taxes		1,804.7		1,749.9
Regulatory Liabilities and Deferred Investment Tax Credits		1,238.8		1,224.7
TOTAL NONCURRENT LIABILITIES		8,025.1		7,753.2
TOTAL LIABILITIES		9,441.0		8,970.9
Equity [Abstract]
Retained Earnings		2,534.4		2,248.0
TOTAL LIABILITIES AND EQUITY		14,088.9		13,315.2
Operating Activites
Net Income (Loss)		348.9		369.7	306.3
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization		546.2		507.5	466.8
Deferred Income Taxes		15.0		(26.2)	(126.2)
Allowance for Equity Funds Used During Construction		(15.6)		(14.6)	(16.6)
Change in Other Noncurrent Assets		(68.8)		(40.4)	(38.2)
Increase (Decrease) in Other Noncurrent Liabilities		35.6		11.2	(40.3)
Accounts Receivable, Net		(53.3)		(30.2)	35.7
Accounts Payable		36.8		(48.1)	37.7
Accrued Taxes, Net		(16.2)		31.3	(10.2)
Net Cash Flows from Operating Activities		611.7		712.0	661.4
Investing Activities
Net Cash Flows Used for Investing Activities		(826.5)		(757.9)	(837.4)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities		212.2		41.8	173.0
Cash and Cash Equivalents at Beginning of Period		5.8
Cash and Cash Equivalents at End of Period		2.5		5.8
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts		207.5		207.1	190.7
Income Taxes		32.8		0.0	63.0
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid		139.1		105.6	149.7
Construction Expenditures Included in Current Liabilities as of December 31,		139.1		105.6	149.7
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt		494.0		606.9	478.2
Repayments of Long-term Debt		393.0		140.3	180.5
Net Income (Loss)		348.9		369.7	306.3
Retained Earnings		2,534.4		2,248.0
Appalachian Power Co [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)		348.9		369.7	306.3
Operating Activites
Net Income (Loss)		348.9		369.7	306.3
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)		$ 348.9		369.7	306.3
Appalachian Power Co [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation		25.00%
Appalachian Power Co [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		59.00%
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		59.00%
Appalachian Power Co [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		40.00%
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		$ 137.0		177.0
Indiana Michigan Power Co [Member]
Materials and Supplies		175.2		175.8
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment		424.9		393.3	330.6
Amortization of Certain Securitized Assets		0.0		0.0	0.0
Amortization of Regulatory Assets and Liabilities		21.1		18.3	20.0
Total Depreciation and Amortization		446.0		411.6	350.6
Ohio Valley Electric Corporation - Barging and Other Transportation Services (43.47% Owned)		54.0		60.8	63.4
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period		3.3		2.0	2.4
Revenues
TOTAL REVENUES		2,326.7		2,241.8	2,306.7
Expenses
Depreciation and Amortization		446.0		411.6	350.6
TOTAL EXPENSES		1,968.8		1,878.9	1,965.9
OPERATING INCOME (LOSS)		357.9		362.9	340.8
Other Income (Expense)
Allowance for Equity Funds Used During Construction		12.8		11.5	19.4
Interest Expense		(116.8)		(112.3)	(117.9)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)		269.2		277.3	258.8
Income Tax Expense (Benefit)		(10.6)		(7.5)	(10.6)
Net Income (Loss)		279.8		284.8	269.4
Accounts Receivable:
Customers		40.6		44.0
Total Accounts Receivable		121.2		97.0
Accrued Tax Benefits		12.7		10.3
TOTAL CURRENT ASSETS		439.4		418.8
Property, Plant and Equipment
Transmission		1,783.1		1,696.4
Other Property, Plant and Equipment		792.9		686.7
Construction Work in Progress		302.8		362.4
Total Property, Plant and Equipment		11,210.7		10,604.8
Accumulated Depreciation and Amortization		3,899.8		3,552.5
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		7,310.9		7,052.3
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS		4,657.9		4,167.2
TOTAL ASSETS		12,408.2		11,638.3
Current Liabilities
Accounts Payable		174.4		153.2
Affiliated Companies		94.9		80.5
Accrued Taxes		106.5		102.5
TOTAL CURRENT LIABILITIES		894.0		1,104.5
Liabilities, Noncurrent
Deferred Income Taxes		1,100.2		1,064.4
Regulatory Liabilities and Deferred Investment Tax Credits		2,447.9		2,041.9
TOTAL NONCURRENT LIABILITIES		8,729.5		7,784.6
TOTAL LIABILITIES		9,623.5		8,889.1
Equity [Abstract]
Retained Earnings		1,748.5		1,718.7
TOTAL LIABILITIES AND EQUITY		12,408.2		11,638.3
Operating Activites
Net Income (Loss)		279.8		284.8	269.4
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization		446.0		411.6	350.6
Deferred Income Taxes		(38.0)		(16.2)	(52.7)
Allowance for Equity Funds Used During Construction		(12.8)		(11.5)	(19.4)
Change in Other Noncurrent Assets		(54.1)		6.1	8.3
Increase (Decrease) in Other Noncurrent Liabilities		7.5		45.0	33.7
Accounts Receivable, Net		(22.3)		14.5	35.4
Accounts Payable		42.3		(10.8)	3.6
Accrued Taxes, Net		1.6		(20.2)	48.3
Net Cash Flows from Operating Activities		733.7		776.3	685.2
Investing Activities
Net Cash Flows Used for Investing Activities		(633.1)		(648.9)	(720.1)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities		(102.6)		(126.1)	34.5
Net Increase (Decrease) in Cash and Cash Equivalents		(2.0)		1.3	(0.4)
Cash and Cash Equivalents at Beginning of Period		3.3		2.0	2.4
Cash and Cash Equivalents at End of Period		1.3		3.3	2.0
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts		110.9		107.6	111.9
Income Taxes		29.3		42.1	3.4
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid		87.8		62.8	86.0
Construction Expenditures Included in Current Liabilities as of December 31,		87.8		62.8	86.0
Acquisition of Nuclear Fuel Included in Current Liabilities as of December 31,		0.0		33.4	0.1
Expected Reimbursement For Spent Nuclear Fuel Dry Cask Storage		1.7		2.6	0.3
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt		546.7		69.5	123.3
Repayments of Long-term Debt		383.5		93.2	117.1
Net Income (Loss)		279.8		284.8	269.4
Retained Earnings		1,748.5		1,718.7
Indiana Michigan Power Co [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)		279.8		284.8	269.4
Operating Activites
Net Income (Loss)		279.8		284.8	269.4
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)		$ 279.8		284.8	269.4
Indiana Michigan Power Co [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation		25.00%
Indiana Michigan Power Co [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		59.00%
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		59.00%
Indiana Michigan Power Co [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		40.00%
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		$ 137.0		177.0
Ohio Power Co [Member]
Materials and Supplies		74.1		66.9
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment		301.1		275.0	229.4
Amortization of Certain Securitized Assets		0.0		0.0	22.0
Amortization of Regulatory Assets and Liabilities		2.2		1.6	(10.5)
Total Depreciation and Amortization		303.3		276.6	240.9
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period		7.4
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		3.0		7.4	3.7	$ 32.5
Revenues
TOTAL REVENUES		2,899.1		2,749.1	2,797.6
Expenses
Depreciation and Amortization		303.3		276.6	240.9
TOTAL EXPENSES		2,513.9		2,345.4	2,396.4
OPERATING INCOME (LOSS)		385.2		403.7	401.2
Other Income (Expense)
Allowance for Equity Funds Used During Construction		10.8		12.5	18.2
Interest Expense		(124.4)		(117.2)	(106.2)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)		288.0		316.6	332.0
Income Tax Expense (Benefit)		34.4		45.2	34.9
Net Income (Loss)		253.6		271.4	297.1
Accounts Receivable:
Customers		71.6		50.0
Total Accounts Receivable		150.0		133.2
TOTAL CURRENT ASSETS		327.5		256.3
Property, Plant and Equipment
Transmission		2,992.8		2,831.9
Other Property, Plant and Equipment		992.9		899.6
Construction Work in Progress		365.0		362.3
Total Property, Plant and Equipment		10,421.3		9,802.1
Accumulated Depreciation and Amortization		2,458.3		2,350.0
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		7,963.0		7,452.1
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS		975.3		1,002.0
TOTAL ASSETS		9,265.8		8,710.4
Current Liabilities
Accounts Payable		213.5		181.0
Affiliated Companies		125.4		118.4
Accrued Taxes		702.4		631.0
TOTAL CURRENT LIABILITIES		1,245.7		1,906.2
Liabilities, Noncurrent
Deferred Income Taxes		1,000.9		955.1
Regulatory Liabilities and Deferred Investment Tax Credits		1,020.9		1,005.2
TOTAL NONCURRENT LIABILITIES		5,173.8		4,111.5
TOTAL LIABILITIES		6,419.5		6,017.7
Equity [Abstract]
Retained Earnings		1,686.3		1,532.7
TOTAL LIABILITIES AND EQUITY		9,265.8		8,710.4
Operating Activites
Net Income (Loss)		253.6		271.4	297.1
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization		303.3		276.6	240.9
Deferred Income Taxes		30.7		77.2	43.8
Allowance for Equity Funds Used During Construction		(10.8)		(12.5)	(18.2)
Amortization of Deferred Property Taxes		(35.3)		(16.6)	(33.7)
Change in Other Noncurrent Assets		(40.7)		(49.4)	(35.3)
Increase (Decrease) in Other Noncurrent Liabilities		6.9		(66.4)	(93.2)
Accounts Receivable, Net		(11.8)		4.2	75.0
Accounts Payable		19.1		10.3	0.4
Accrued Taxes, Net		78.2		43.3	38.7
Net Cash Flows from Operating Activities		575.6		410.9	421.2
Investing Activities
Net Cash Flows Used for Investing Activities		(753.3)		(791.0)	(744.1)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities		173.3		383.8	294.1
Cash and Cash Equivalents at Beginning of Period		7.4
Cash and Cash Equivalents at End of Period		3.0		7.4
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts		119.5		111.2	100.6
Income Taxes		(7.9)		(26.9)	7.3
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid		97.1		76.7	125.9
Construction Expenditures Included in Current Liabilities as of December 31,		97.1		76.7	125.9
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt		1,037.1		347.0	444.3
Repayments of Long-term Debt		500.1		0.1	80.3
Net Income (Loss)		253.6		271.4	297.1
Retained Earnings		1,686.3		1,532.7
Ohio Power Co [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)		253.6		271.4	297.1
Operating Activites
Net Income (Loss)		253.6		271.4	297.1
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)		$ 253.6		271.4	297.1
Ohio Power Co [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation		25.00%
Ohio Power Co [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		59.00%
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		59.00%
Ohio Power Co [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		40.00%
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		$ 137.0		177.0
Public Service Co Of Oklahoma [Member]
Materials and Supplies		56.2		54.0
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment		185.9		171.9	162.5
Amortization of Certain Securitized Assets		0.0		0.0	0.0
Amortization of Regulatory Assets and Liabilities		10.7		1.6	7.0
Total Depreciation and Amortization		196.6		173.5	169.5
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period		2.6		1.5	2.0
Revenues
TOTAL REVENUES		1,474.4		1,266.1	1,481.8
Expenses
Depreciation and Amortization		196.6		173.5	169.5
TOTAL EXPENSES		1,281.5		1,090.2	1,282.5
OPERATING INCOME (LOSS)		192.9		175.9	199.3
Other Income (Expense)
Allowance for Equity Funds Used During Construction		2.4		4.0	2.7
Interest Expense		(62.9)		(60.3)	(66.5)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)		145.2		128.2	145.1
Income Tax Expense (Benefit)		4.1		5.2	7.5
Net Income (Loss)		141.1		123.0	137.6
Accounts Receivable:
Customers		41.5		30.8
Total Accounts Receivable		77.1		48.4
Accrued Tax Benefits		17.6		10.9
TOTAL CURRENT ASSETS		386.8		181.3
Property, Plant and Equipment
Transmission		1,107.7		1,069.9
Other Property, Plant and Equipment		437.0		393.3
Construction Work in Progress		156.0		128.7
Total Property, Plant and Equipment		6,508.0		5,925.6
Accumulated Depreciation and Amortization		1,705.2		1,605.6
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		4,802.8		4,320.0
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS		1,209.4		489.4
TOTAL ASSETS		6,399.0		4,990.7
Current Liabilities
Accounts Payable		157.4		107.0
Affiliated Companies		51.0		43.4
Accrued Taxes		27.0		26.8
TOTAL CURRENT LIABILITIES		562.7		478.6
Liabilities, Noncurrent
Deferred Income Taxes		782.3		688.5
Regulatory Liabilities and Deferred Investment Tax Credits		835.3		802.2
TOTAL NONCURRENT LIABILITIES		3,544.7		2,966.5
TOTAL LIABILITIES		4,107.4		3,445.1
Equity [Abstract]
Retained Earnings		1,095.4		974.3
TOTAL LIABILITIES AND EQUITY		6,399.0		4,990.7
Operating Activites
Net Income (Loss)		141.1		123.0	137.6
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization		196.6		173.5	169.5
Deferred Income Taxes		113.9		17.0	(18.2)
Allowance for Equity Funds Used During Construction		(2.4)		(4.0)	(2.7)
Change in Other Noncurrent Assets		(18.3)		(17.9)	5.7
Increase (Decrease) in Other Noncurrent Liabilities		4.4		1.6	(7.3)
Accounts Receivable, Net		(28.7)		1.4	15.4
Accounts Payable		34.2		(29.5)	7.0
Accrued Taxes, Net		(6.5)		3.6	3.9
Net Cash Flows from Operating Activities		(433.3)		157.0	350.3
Investing Activities
Net Cash Flows Used for Investing Activities		(626.7)		(295.1)	(328.1)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities		1,058.7		139.2	(22.7)
Net Increase (Decrease) in Cash and Cash Equivalents		(1.3)		1.1	(0.5)
Cash and Cash Equivalents at Beginning of Period		2.6		1.5	2.0
Cash and Cash Equivalents at End of Period		1.3		2.6	1.5
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts		57.0		59.1	61.1
Income Taxes		(102.9)		(11.8)	22.4
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid		56.8		35.5	46.0
Construction Expenditures Included in Current Liabilities as of December 31,		56.8		35.5	46.0
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt		1,290.0		0.0	349.5
Repayments of Long-term Debt		750.5		13.2	250.5
Net Income (Loss)		141.1		123.0	137.6
Retained Earnings		1,095.4		974.3
Public Service Co Of Oklahoma [Member] | Retained Earnings [Member]
Other Income (Expense)
Net Income (Loss)		141.1		123.0	137.6
Operating Activites
Net Income (Loss)		141.1		123.0	137.6
Organization and Summary of Significant Accounting Policies (Textuals)
Net Income (Loss)		$ 141.1		123.0	137.6
Public Service Co Of Oklahoma [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation		25.00%
Public Service Co Of Oklahoma [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		59.00%
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		59.00%
Public Service Co Of Oklahoma [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		40.00%
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		$ 137.0		177.0
Southwestern Electric Power Co [Member]
Materials and Supplies		81.9		95.8
Supplementary Information
Depreciation and Amortization of Property, Plant and Equipment		292.9		271.2	247.9
Amortization of Certain Securitized Assets		0.0		0.0	0.0
Amortization of Regulatory Assets and Liabilities		2.1		1.5	1.2
Total Depreciation and Amortization		295.0		272.7	249.1
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period		13.2		1.6	24.5
Amounts Attributable to AEP Common Shareholders
Net Income (Loss) Attributable to Noncontrolling Interests		3.1		2.9	3.6
Net Income (Loss)		239.0		180.8	158.6
Revenues
TOTAL REVENUES		2,131.8		1,738.5	1,750.9
Expenses
Depreciation and Amortization		295.0		272.7	249.1
TOTAL EXPENSES		1,792.3		1,448.0	1,495.2
OPERATING INCOME (LOSS)		339.5		290.5	255.7
Other Income (Expense)
Allowance for Equity Funds Used During Construction		7.0		7.7	6.8
Interest Expense		(125.9)		(118.5)	(119.1)
INCOME BEFORE INCOME TAX EXPENSE (BENEFIT) AND EQUITY EARNINGS (LOSS)		238.1		190.2	154.5
Income Tax Expense (Benefit)		(0.6)		9.4	(4.7)
Net Income (Loss)		242.1		183.7	162.2
Accounts Receivable:
Customers		35.8		27.1
Total Accounts Receivable		86.4		64.9
Accrued Tax Benefits		17.8		29.9
TOTAL CURRENT ASSETS		668.5		428.0
Property, Plant and Equipment
Transmission		2,316.9		2,165.7
Other Property, Plant and Equipment		764.0		788.8
Construction Work in Progress		240.7		228.3
Total Property, Plant and Equipment		10,570.4		10,246.7
Accumulated Depreciation and Amortization		3,170.3		3,158.5
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		7,400.1		7,088.2
Other Noncurrent Assets
TOTAL OTHER NONCURRENT ASSETS		1,257.1		637.9
TOTAL ASSETS		9,325.7		8,154.1
Current Liabilities
Accounts Payable		163.6		135.9
Affiliated Companies		61.4		43.0
Accrued Taxes		44.3		41.0
TOTAL CURRENT LIABILITIES		538.7		763.6
Liabilities, Noncurrent
Deferred Income Taxes		1,087.6		1,017.6
Regulatory Liabilities and Deferred Investment Tax Credits		806.9		863.4
TOTAL NONCURRENT LIABILITIES		5,637.2		4,762.8
TOTAL LIABILITIES		6,175.9		5,526.4
Equity [Abstract]
Retained Earnings		2,050.9		1,811.9
TOTAL LIABILITIES AND EQUITY		9,325.7		8,154.1
Operating Activites
Net Income (Loss)		242.1		183.7	162.2
Adjustments to Reconcile Net Income to Net Cash Flows from (Used for) Operating Activities:
Depreciation and Amortization		295.0		272.7	249.1
Deferred Income Taxes		16.6		32.4	(11.0)
Allowance for Equity Funds Used During Construction		(7.0)		(7.7)	(6.8)
Change in Other Noncurrent Assets		41.9		16.1	2.7
Increase (Decrease) in Other Noncurrent Liabilities		(1.1)		25.2	2.7
Accounts Receivable, Net		(21.5)		7.3	0.0
Accounts Payable		22.0		11.1	(28.4)
Accrued Taxes, Net		15.4		(23.1)	(3.2)
Net Cash Flows from Operating Activities		96.8		356.3	339.8
Investing Activities
Net Cash Flows Used for Investing Activities		(920.7)		(392.6)	(330.2)
Net Cash Provided by (Used in) Financing Activities
Net Cash Flows from Financing Activities		861.9		47.9	(32.5)
Net Increase (Decrease) in Cash and Cash Equivalents		38.0		11.6	(22.9)
Cash and Cash Equivalents at Beginning of Period		13.2		1.6	24.5
Cash and Cash Equivalents at End of Period		51.2		13.2	1.6
Cash Paid (Received) for:
Cash Paid for Interest, Net of Capitalized Amounts		116.5		110.7	111.1
Income Taxes		(28.8)		4.3	8.6
Noncash Investing and Financing Activities:
Construction in Progress Expenditures Incurred but Not yet Paid		69.0		46.0	69.1
Construction Expenditures Included in Current Liabilities as of December 31,		69.0		46.0	69.1
Organization and Summary of Significant Accounting Policies (Textuals)
Issuance of Long-term Debt		1,137.6		0.0	0.0
Repayments of Long-term Debt		381.2		21.2	59.7
Income (Loss) from Equity Method Investment		3.4		2.9	3.0
Net Income (Loss)		242.1		183.7	162.2
Retained Earnings		2,050.9		1,811.9
Southwestern Electric Power Co [Member] | Retained Earnings [Member]
Amounts Attributable to AEP Common Shareholders
Net Income (Loss)		$ 239.0		180.8	$ 158.6
Southwestern Electric Power Co [Member] | Pension Plans [Member] | Equity [Member]
Target Asset Allocations
Target Asset Allocation		25.00%
Southwestern Electric Power Co [Member] | Pension Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		59.00%
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		59.00%
Southwestern Electric Power Co [Member] | Other Postretirement Benefit Plans [Member] | Fixed Income [Member]
Target Asset Allocations
Target Asset Allocation		40.00%
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		$ 137.0		$ 177.0
Restricted Stock Units and Performance Share Units [Member]
Weighted Average Dilutive Effect of:
Weighted Average Dilutive Effect of Shares		1,300,000		1,500,000	1,600,000
Dilutive Securities, Effect on Basic Earnings Per Share		$ (0.01)		$ (0.02)	$ (0.01)
Revenues [Member] | AEP Texas Inc. [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk	[6]	43.00%		46.00%	48.00%
Revenues [Member] | AEP Transmission Co [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk		79.00%		78.00%	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	[6]	41.00%		40.00%	43.00%
Accounts Receivable [Member] | AEP Transmission Co [Member] | Credit Concentration Risk
Risks and Uncertainties
Percentage of Significant Customers Concentration Risk		81.00%		78.00%	78.00%
Noncontrolling Interest [Member] | Dry Lake Solar Project [Member]
Noncash Investing and Financing Activities:
Noncash Contribution of Assets by Noncontrolling Interest		$ 35.3		$ 0.0	$ 0.0
Noncontrolling Interest [Member] | Sempra Renewables LLC and Santa Rita East Acquisition [Member]
Noncash Investing and Financing Activities:
Noncash Contribution of Assets by Noncontrolling Interest		0.0		0.0	$ 253.4
Sabine Mining Co [Member] | Southwestern Electric Power Co [Member]
Materials and Supplies		12.0		23.3
Cash, Cash Equivalents and Restricted Cash
Cash and Cash Equivalents at Beginning of Period		10.1
Property, Plant and Equipment
Other Property, Plant and Equipment		219.9		223.7
Accumulated Depreciation and Amortization		168.1		126.5
Net Cash Provided by (Used in) Financing Activities
Cash and Cash Equivalents at Beginning of Period		10.1
Cash and Cash Equivalents at End of Period		$ 49.9		$ 10.1

[1] Amount excludes $2.3 billion and $165 million for AEP and AEPTCo, 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] Amount includes Assets Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[3] 2021 amounts exclude $148 million of regulatory liabilities classified as Liabilities Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[4] Amount includes Assets Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[5] 2021 amounts exclude $8 million of regulatory liabilities classified as Liabilities Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[6] In January 2021, NRG Energy, parent company of Reliant Energy, completed a deal to purchase Direct Energy from Centrica.