Consolidated Statements of Income - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2018		Sep. 30, 2017		Sep. 30, 2018		Sep. 30, 2017
Revenues
Revenue from Contracts with Customers		$ 4,333.1		$ 4,104.7		$ 12,394.6		$ 11,614.5
Sales to AEP Affiliates		0.0		0.0		0.0		0.0
TOTAL REVENUES		4,333.1		4,104.7		12,394.6		11,614.5
Expenses
Other Operation		826.0		644.0		2,332.7		1,884.1
Maintenance		316.6		269.0		911.0		862.6
Gain on Sale of Merchant Generation Assets		0.0		0.0		0.0		(226.4)
Depreciation and Amortization		602.6		518.5		1,695.5		1,485.9
Taxes Other Than Income Taxes		294.2		272.6		863.0		792.0
TOTAL EXPENSES		3,664.5		3,129.6		10,263.0		8,820.4
OPERATING INCOME (LOSS)		668.6		975.1		2,131.6		2,794.1
Other Income (Expense):
Interest and Investment Income		5.4		2.4		11.3		12.7
Carrying Costs Income		0.9		2.6		7.2		14.2
Allowance for Equity Funds Used During Construction		30.9		20.0		92.4		62.2
Non-Service Cost Components of Net Periodic Benefit Cost		31.9		11.4		95.3		34.2
Gain (Loss) on Disposition of Stock in Subsidiary or Equity Method Investee		0.0		12.4		0.0		12.4
Interest Expense		(256.8)		(223.3)		(733.1)		(668.0)
INCOME BEFORE INCOME TAX EXPENSE AND EQUITY EARNINGS		480.9		800.6		1,604.7		2,261.8
Income Tax Expense (Credit)		(80.7)		264.0		93.5		797.8
Equity Earnings (Loss) of Unconsolidated Subsidiaries		18.1		20.1		55.3		63.1
Net Income (Loss)		579.7		556.7		1,566.5		1,527.1
Net Income Attributable to Noncontrolling Interests		2.1		12.0		6.1		15.2
Earnings Attributable to Common Shareholders		$ 577.6		$ 544.7		$ 1,560.4		$ 1,511.9
Earnings Per Share
Weighted Average Number of Basic AEP Common Shares Outstanding		492,984,741		491,840,722		492,649,456		491,781,643
Basic Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations		$ 1.17		$ 1.11		$ 3.17		$ 3.07
Total Basic Earnings Per Share Attributable to AEP Common Shareholders		$ 1.17		$ 1.11		$ 3.17		$ 3.07
Weighted Average Number of Diluted AEP Common Shares Outstanding		493,940,543		492,986,307		493,526,937		492,428,586
Diluted Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations		$ 1.17		$ 1.10		$ 3.16		$ 3.07
Total Diluted Earnings Per Share Attributable to AEP Common Shareholders		1.17		1.10		3.16		3.07
Common Stock, Dividends Per Share, Declared		$ 0.62		$ 0.59		$ 1.86		$ 1.77
Vertically Integrated Utilities [Member]
Revenues
Revenue from Contracts with Customers		$ 2,610.2		$ 2,453.8		$ 7,332.4		$ 6,819.3
Transmission and Distribution Utilities [Member]
Revenues
Revenue from Contracts with Customers		1,180.9		1,149.7		3,450.0		3,242.7
Generation and Marketing [Member]
Revenues
Revenue from Contracts with Customers		486.5		441.5		1,399.3		1,386.8
Other Revenues [Member]
Revenues
Revenue from Contracts with Customers		55.5		59.7		212.9		165.7
TOTAL REVENUES		58.6	[1]			78.5	[2]
Fuel and Other Consumables Used for Electric Generation [Member]
Revenues
Revenue from Contracts with Customers		240.8	[3]			944.7	[4]
Expenses
Cost of Goods and Services Sold		840.4		707.4		1,909.1		1,865.3
Purchased Electricity for Resale [Member]
Expenses
Cost of Goods and Services Sold		784.7		718.1		2,551.7		2,156.9
AEP Texas Inc. [Member]
Revenues
Revenue from Contracts with Customers		407.3
Sales to AEP Affiliates		27.5		18.9		63.3		50.8
TOTAL REVENUES		433.4		431.2		1,193.3		1,164.3
Expenses
Other Operation		133.4		117.5		368.4		332.8
Maintenance		23.2		19.3		67.8		58.1
Depreciation and Amortization		133.3		124.0		364.9		343.0
Taxes Other Than Income Taxes		36.3		33.3		102.3		93.3
TOTAL EXPENSES		339.4		302.4		931.3		844.4
OPERATING INCOME (LOSS)		94.0		128.8		262.0		319.9
Other Income (Expense):
Interest Income		0.5		0.5		0.0		1.6
Allowance for Equity Funds Used During Construction		5.8		0.0		15.2		2.2
Non-Service Cost Components of Net Periodic Benefit Cost		3.1		0.9		9.2		2.7
Interest Expense		(37.3)		(35.3)		(108.9)		(105.6)
INCOME BEFORE INCOME TAX EXPENSE AND EQUITY EARNINGS		66.1		94.9		177.5		220.8
Income Tax Expense (Credit)		8.3		30.6		26.4		74.2
Net Income (Loss)		57.8		64.3		151.1		146.6
AEP Texas Inc. [Member] | Transmission and Distribution Utilities [Member]
Revenues
Revenue from Contracts with Customers		404.5		411.5		1,127.0		1,111.4
AEP Texas Inc. [Member] | Other Revenues [Member]
Revenues
Revenue from Contracts with Customers		1.4		0.8		3.0		2.1
TOTAL REVENUES		27.1	[5]			62.1	[6]
AEP Texas Inc. [Member] | Fuel and Other Consumables Used for Electric Generation [Member]
Revenues
Revenue from Contracts with Customers		0.0	[7]			0.0	[8]
Expenses
Cost of Goods and Services Sold		13.2		8.3		27.9		17.2
AEP Transmission Co [Member]
Revenues
Revenue from Contracts with Customers	[9]	206.8
Sales to AEP Affiliates		148.4		130.1	[10]	453.8	[10]	439.1	[10]
TOTAL REVENUES		194.4	[9]	165.6	[10]	586.2	[9],[10]	534.8	[10]
Expenses
Other Operation		24.5		18.4		59.6		38.8
Maintenance		2.8		1.4		7.6		6.8
Depreciation and Amortization		34.9		24.6		97.5		69.7
Taxes Other Than Income Taxes		35.2		27.6		102.9		82.0
TOTAL EXPENSES		97.4		72.0		267.6		197.3
OPERATING INCOME (LOSS)		97.0		93.6		318.6		337.5
Other Income (Expense):
Interest Income		0.5		0.2	[10]	1.3	[10]	0.5	[10]
Allowance for Equity Funds Used During Construction		18.0		11.4		48.7		33.0
Interest Expense		(19.8)		(17.1)	[10]	(60.7)	[10]	(50.4)	[10]
INCOME BEFORE INCOME TAX EXPENSE AND EQUITY EARNINGS		95.7		88.1		307.9		320.6
Income Tax Expense (Credit)		17.6		29.5	[10]	63.7	[10]	108.2	[10]
Net Income (Loss)		78.1		58.6	[10]	244.2	[10]	212.4	[10]
AEP Transmission Co [Member] | Transmission [Member]
Revenues
Revenue from Contracts with Customers		46.0		35.6	[10]	132.3	[10]	95.7	[10]
AEP Transmission Co [Member] | Other Revenues [Member]
Revenues
Revenue from Contracts with Customers		0.0		(0.1)	[10]	0.1	[10]	0.0	[10]
TOTAL REVENUES	[9]	0.0	[5]			0.0	[6]
AEP Transmission Co [Member] | Fuel and Other Consumables Used for Electric Generation [Member]
Revenues
Revenue from Contracts with Customers	[9]	0.0	[7]			0.0	[8]
Appalachian Power Co [Member]
Revenues
Revenue from Contracts with Customers		764.1
Sales to AEP Affiliates		42.9		41.9		138.7		130.6
TOTAL REVENUES		762.0		719.3		2,249.4		2,187.4
Expenses
Other Operation		131.9		117.0		380.0		370.1
Maintenance		97.2		55.8		234.9		187.8
Depreciation and Amortization		105.7		102.8		319.5		304.1
Taxes Other Than Income Taxes		33.6		32.3		101.1		93.3
TOTAL EXPENSES		712.2		547.6		1,874.0		1,670.7
OPERATING INCOME (LOSS)		49.8		171.7		375.4		516.7
Other Income (Expense):
Interest Income		0.4		0.3		1.3		1.1
Carrying Costs Income		0.2		0.4		1.2		1.0
Allowance for Equity Funds Used During Construction		4.1		2.7		9.6		6.2
Non-Service Cost Components of Net Periodic Benefit Cost		4.5		1.3		13.4		3.9
Interest Expense		(50.8)		(47.2)		(146.0)		(143.5)
INCOME BEFORE INCOME TAX EXPENSE AND EQUITY EARNINGS		8.2		129.2		254.9		385.4
Income Tax Expense (Credit)		(78.9)		43.2		(35.1)		136.7
Net Income (Loss)		87.1		86.0		290.0		248.7
Appalachian Power Co [Member] | Vertically Integrated Utilities [Member]
Revenues
Revenue from Contracts with Customers		716.8		674.4		2,103.1		2,045.0
Appalachian Power Co [Member] | Other Revenues [Member]
Revenues
Revenue from Contracts with Customers		2.3		3.0		7.6		11.8
TOTAL REVENUES		(0.9)	[5]			(0.9)	[6]
Appalachian Power Co [Member] | Fuel and Other Consumables Used for Electric Generation [Member]
Revenues
Revenue from Contracts with Customers		74.5	[7]			194.1	[8]
Sales to AEP Affiliates		30.0				100.0
Expenses
Cost of Goods and Services Sold		263.4		178.6		487.7		498.3
Appalachian Power Co [Member] | Purchased Electricity for Resale [Member]
Expenses
Cost of Goods and Services Sold		80.4		61.1		350.8		217.1
Indiana Michigan Power Co [Member]
Revenues
Revenue from Contracts with Customers		619.5
Other Revenues - Affiliated		17.1		17.1		62.2		48.2
TOTAL REVENUES		629.7		557.7		1,796.2		1,585.5
Expenses
Purchased Electricity from AEP Affiliates		60.0		62.4		181.8		166.2
Other Operation		149.3		142.0		425.8		438.8
Maintenance		57.2		51.5		169.1		153.6
Depreciation and Amortization		85.2		55.0		207.1		154.8
Taxes Other Than Income Taxes		23.0		23.9		72.9		68.3
TOTAL EXPENSES		519.5		444.1		1,471.2		1,321.1
OPERATING INCOME (LOSS)		110.2		113.6		325.0		264.4
Other Income (Expense):
Interest Income		1.6		0.2		2.8		1.6
Carrying Costs Income		0.6		2.2		4.6		9.9
Allowance for Equity Funds Used During Construction		3.9		3.5		8.0		8.1
Non-Service Cost Components of Net Periodic Benefit Cost		4.6		1.5		13.6		4.6
Interest Expense		(34.5)		(27.5)		(95.6)		(83.0)
INCOME BEFORE INCOME TAX EXPENSE AND EQUITY EARNINGS		86.4		93.5		258.4		205.6
Income Tax Expense (Credit)		13.7		28.6		26.8		61.8
Net Income (Loss)		72.7		64.9		231.6		143.8
Indiana Michigan Power Co [Member] | Vertically Integrated Utilities [Member]
Revenues
Revenue from Contracts with Customers		609.9		537.0		1,723.9		1,527.4
Indiana Michigan Power Co [Member] | Other Revenues [Member]
Revenues
Revenue from Contracts with Customers		2.7		3.6		10.1		9.9
Sales to AEP Affiliates		17.0				57.0
TOTAL REVENUES		8.7	[5]			0.0	[6]
Indiana Michigan Power Co [Member] | Fuel and Other Consumables Used for Electric Generation [Member]
Revenues
Revenue from Contracts with Customers		93.6	[7]			349.7	[8]
Expenses
Cost of Goods and Services Sold		95.9		76.4		246.8		238.2
Indiana Michigan Power Co [Member] | Purchased Electricity for Resale [Member]
Expenses
Cost of Goods and Services Sold		48.9		32.9		167.7		101.2
Ohio Power Co [Member]
Revenues
Revenue from Contracts with Customers		740.9
Sales to AEP Affiliates		3.3		4.6		17.9		19.4
TOTAL REVENUES		778.3		742.0		2,318.0		2,152.0
Expenses
Purchased Electricity from AEP Affiliates		39.3		26.7		97.4		83.4
Amortization of Generation Deferrals		56.9		58.7		171.9		172.9
Other Operation		215.2		126.9		586.4		380.9
Maintenance		43.4		37.9		114.7		108.4
Depreciation and Amortization		70.4		57.3		200.3		165.7
Taxes Other Than Income Taxes		106.9		100.4		311.0		293.8
TOTAL EXPENSES		698.4		588.6		2,016.4		1,730.5
OPERATING INCOME (LOSS)		79.9		153.4		301.6		421.5
Other Income (Expense):
Interest Income		0.8		0.7		2.6		4.0
Carrying Costs Income		0.2		0.5		1.5		3.0
Allowance for Equity Funds Used During Construction		2.0		0.9		7.8		4.1
Non-Service Cost Components of Net Periodic Benefit Cost		3.8		1.1		11.6		3.3
Interest Expense		(26.1)		(25.7)		(76.6)		(76.8)
INCOME BEFORE INCOME TAX EXPENSE AND EQUITY EARNINGS		60.6		130.9		248.5		359.1
Income Tax Expense (Credit)		(28.1)		48.3		11.4		128.0
Net Income (Loss)		88.7		82.6		237.1		231.1
Ohio Power Co [Member] | Transmission and Distribution Utilities [Member]
Revenues
Revenue from Contracts with Customers		772.6		736.0		2,294.8		2,127.8
Ohio Power Co [Member] | Other Revenues [Member]
Revenues
Revenue from Contracts with Customers		2.4		1.4		5.3		4.8
TOTAL REVENUES		74.3	[5]			82.3	[6]
Ohio Power Co [Member] | Fuel and Other Consumables Used for Electric Generation [Member]
Revenues
Revenue from Contracts with Customers		0.0	[7]			0.0	[8]
Ohio Power Co [Member] | Purchased Electricity for Resale [Member]
Expenses
Cost of Goods and Services Sold		166.3		180.7		534.7		525.4
Public Service Co Of Oklahoma [Member]
Revenues
Revenue from Contracts with Customers		479.1
Sales to AEP Affiliates		1.1		1.1		3.7		3.2
TOTAL REVENUES		481.4		442.8		1,216.5		1,091.6
Expenses
Other Operation		106.3		84.5		286.8		228.9
Maintenance		22.3		25.2		73.2		88.2
Depreciation and Amortization		42.3		31.7		120.5		97.8
Taxes Other Than Income Taxes		10.8		9.8		32.6		30.0
TOTAL EXPENSES		402.9		356.9		1,076.9		940.5
OPERATING INCOME (LOSS)		78.5		85.9		139.6		151.1
Other Income (Expense):
Allowance for Equity Funds Used During Construction						(0.3)		0.4
Other Income		(0.2)		0.0		(0.3)		0.5
Non-Service Cost Components of Net Periodic Benefit Cost		2.1		0.9		6.5		2.6
Interest Expense		(16.4)		(13.2)		(47.4)		(40.2)
INCOME BEFORE INCOME TAX EXPENSE AND EQUITY EARNINGS		64.0		73.6		98.4		114.0
Income Tax Expense (Credit)		3.6		27.4		8.6		42.6
Net Income (Loss)		60.4		46.2		89.8		71.4
Public Service Co Of Oklahoma [Member] | Vertically Integrated Utilities [Member]
Revenues
Revenue from Contracts with Customers		479.1		440.6		1,209.5		1,085.1
Public Service Co Of Oklahoma [Member] | Other Revenues [Member]
Revenues
Revenue from Contracts with Customers		1.2		1.1		3.3		3.3
TOTAL REVENUES		0.0	[5]			0.0	[6]
Public Service Co Of Oklahoma [Member] | Fuel and Other Consumables Used for Electric Generation [Member]
Revenues
Revenue from Contracts with Customers		12.5	[7]			26.7	[8]
Expenses
Cost of Goods and Services Sold		104.4		77.9		211.5		115.8
Public Service Co Of Oklahoma [Member] | Purchased Electricity for Resale [Member]
Expenses
Cost of Goods and Services Sold		116.8		127.8		352.3		379.8
Southwestern Electric Power Co [Member]
Revenues
Revenue from Contracts with Customers		535.6
Sales to AEP Affiliates		8.7		7.7		20.2		20.4
TOTAL REVENUES		535.3		517.6		1,411.8		1,343.6
Expenses
Other Operation		99.1		81.2		292.0		234.9
Maintenance		33.6		32.6		102.2		106.5
Depreciation and Amortization		59.9		55.2		175.9		158.1
Taxes Other Than Income Taxes		26.9		25.1		76.4		72.7
TOTAL EXPENSES		408.2		381.6		1,172.6		1,080.7
OPERATING INCOME (LOSS)		127.1		136.0		239.2		262.9
Other Income (Expense):
Interest Income		1.1		0.7		3.5		2.0
Allowance for Equity Funds Used During Construction		0.6		0.4		3.8		1.2
Non-Service Cost Components of Net Periodic Benefit Cost		2.3		1.0		6.9		2.8
Interest Expense		(32.7)		(31.9)		(95.8)		(92.7)
INCOME BEFORE INCOME TAX EXPENSE AND EQUITY EARNINGS		98.4		106.2		157.6		176.2
Income Tax Expense (Credit)		9.6		22.5		17.9		45.2
Equity Earnings (Loss) of Unconsolidated Subsidiaries		0.8		0.4		2.0		(4.5)
Net Income (Loss)		89.6		84.1		141.7		126.5
Net Income Attributable to Noncontrolling Interests		1.4		11.0		4.1		12.6
Earnings Attributable to Common Shareholders		88.2		73.1		137.6		113.9
Southwestern Electric Power Co [Member] | Vertically Integrated Utilities [Member]
Revenues
Revenue from Contracts with Customers		526.0		509.5		1,390.4		1,321.8
Southwestern Electric Power Co [Member] | Other Revenues [Member]
Revenues
Revenue from Contracts with Customers		0.6		0.4		1.2		1.4
TOTAL REVENUES		0.0	[5]			0.0	[6]
Southwestern Electric Power Co [Member] | Fuel and Other Consumables Used for Electric Generation [Member]
Revenues
Revenue from Contracts with Customers		53.2	[7]			168.8	[8]
Expenses
Cost of Goods and Services Sold		152.1		147.5		393.4		389.8
Southwestern Electric Power Co [Member] | Purchased Electricity for Resale [Member]
Expenses
Cost of Goods and Services Sold		$ 36.6		$ 40.0		$ 132.7		$ 118.7

[1] Amounts include affiliated and nonaffiliated revenues.

[2] Amounts include affiliated and nonaffiliated revenues.

[3] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing is $35 million. The remaining affiliated amounts are immaterial.

[4] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for Generation & Marketing is $87 million. The remaining affiliated amounts are immaterial.

[5] Amounts include affiliated and nonaffiliated revenues.

[6] Amounts include affiliated and nonaffiliated revenues.

[7] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo is $30 million primarily relating to the PPA with Kingsport. The remaining affiliated amounts are immaterial.

[8] Amounts include affiliated and nonaffiliated revenues. The affiliated revenue for APCo is $100 million primarily relating to the PPA with Kingsport. The remaining affiliated amounts are immaterial.

[9] The amounts presented reflect the revisions made to AEPTCo’s previously issued financial statements. For additional details on revisions made to AEPTCo’s financial statements, see Note 1- Significant Accounting Matters.

[10] The amounts presented reflect the revisions made to AEPTCo’s previously issued financial statements. For additional details on revisions made to AEPTCo’s financial statements, see Note 1- Significant Accounting Matters.