Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues
Vertically Integrated Utilities	$ 2,095.7	$ 2,108.2	$ 4,365.5	$ 4,326.3
Transmission and Distribution Utilities	1,026.6	1,076.2	2,093.0	2,153.5
Generation & Marketing	386.5	655.3	945.3	1,369.2
Other Revenues	67.7	53.2	106.0	88.8
TOTAL REVENUES	3,576.5	3,892.9	7,509.8	7,937.8
Expenses
Fuel and Other Consumables Used for Electric Generation	522.3	680.4	1,157.9	1,356.0
Purchased Electricity for Resale	669.2	629.2	1,438.8	1,360.6
Other Operation	604.2	664.5	1,206.4	1,379.6
Maintenance	289.0	289.4	591.4	568.1
Asset Impairments and Other Related Charges	1.9	0.0	13.1	0.0
Gain on Sale of Merchant Generation Assets	0.1	0.0	(226.4)	0.0
Depreciation and Amortization	485.5	513.8	967.4	1,010.9
Taxes Other Than Income Taxes	259.6	249.4	519.4	503.5
TOTAL EXPENSES	2,831.8	3,026.7	5,668.0	6,178.7
OPERATING INCOME (LOSS)	744.7	866.2	1,841.8	1,759.1
Other Income (Expense):
Interest and Investment Income	2.3	2.4	10.3	4.5
Carrying Costs Income	5.7	6.3	11.6	10.2
Allowance for Equity Funds Used During Construction	21.0	28.8	42.2	60.5
Interest Expense	(222.9)	(224.9)	(444.7)	(441.9)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	550.8	678.8	1,461.2	1,392.4
Income Tax Expense (Credit)	190.6	165.0	533.8	400.5
Equity Earnings (Loss) of Unconsolidated Subsidiaries	16.0	(7.4)	43.0	17.6
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	376.2	506.4	970.4	1,009.5
Income (Loss) from Discontinued Operations, Net of Tax	0.0	(2.5)	0.0	(2.5)
Net Income (Loss)	376.2	503.9	970.4	1,007.0
Net Income Attributable to Noncontrolling Interests	1.2	1.8	3.2	3.7
Earnings Attributable to Common Shareholders	$ 375.0	$ 502.1	$ 967.2	$ 1,003.3
Earnings Per Share
Weighted Average Number of Basic AEP Common Shares Outstanding	491,790,752	491,459,541	491,751,614	491,283,967
Basic Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ 0.76	$ 1.03	$ 1.97	$ 2.05
Basic Earnings Per Share Attributable to AEP Common Shareholders from Discontinued Operations	0.00	(0.01)	0.00	(0.01)
Total Basic Earnings Per Share Attributable to AEP Common Shareholders	$ 0.76	$ 1.02	$ 1.97	$ 2.04
Weighted Average Number of Diluted AEP Common Shares Outstanding	492,642,100	491,641,400	492,337,255	491,486,853
Diluted Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ 0.76	$ 1.03	$ 1.96	$ 2.05
Diluted Earnings Per Share Attributable to AEP Common Shareholders from Discontinued Operations	0.00	(0.01)	0.00	(0.01)
Total Diluted Earnings Per Share Attributable to AEP Common Shareholders	0.76	1.02	1.96	2.04
Common Stock, Dividends Per Share, Declared	$ 0.59	$ 0.56	$ 1.18	$ 1.12
AEP Transmission Co [Member]
Revenues
Electrical Transmission Revenue	$ 44.0	$ 34.1	$ 63.3	$ 56.1
Sales to AEP Affiliates	185.4	119.0	318.8	176.6
TOTAL REVENUES	229.4	153.1	382.1	232.7
Expenses
Other Operation	11.3	6.3	20.4	13.5
Maintenance	2.3	1.4	5.4	2.9
Depreciation and Amortization	22.8	15.6	46.1	30.7
Taxes Other Than Income Taxes	27.6	21.7	54.4	42.7
TOTAL EXPENSES	64.0	45.0	126.3	89.8
OPERATING INCOME (LOSS)	165.4	108.1	255.8	142.9
Other Income (Expense):
Interest Income	0.1	0.1	0.3	0.1
Allowance for Equity Funds Used During Construction	13.4	14.1	24.3	26.4
Interest Expense	(15.7)	(10.5)	(31.7)	(21.3)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	163.2	111.8	248.7	148.1
Income Tax Expense (Credit)	55.8	37.0	84.3	47.5
Net Income (Loss)	107.4	74.8	164.4	100.6
Appalachian Power Co [Member]
Revenues
Vertically Integrated Utilities	625.6	638.8	1,370.6	1,414.3
Sales to AEP Affiliates	46.3	32.2	88.7	72.6
Other Revenues	3.4	2.5	8.8	6.6
TOTAL REVENUES	675.3	673.5	1,468.1	1,493.5
Expenses
Fuel and Other Consumables Used for Electric Generation	152.5	153.3	319.7	304.0
Purchased Electricity for Resale	65.2	63.5	156.0	171.7
Other Operation	137.9	111.2	250.5	231.8
Maintenance	60.8	60.2	132.0	129.5
Depreciation and Amortization	100.7	96.4	201.3	191.9
Taxes Other Than Income Taxes	30.8	30.6	61.0	61.9
TOTAL EXPENSES	547.9	515.2	1,120.5	1,090.8
OPERATING INCOME (LOSS)	127.4	158.3	347.6	402.7
Other Income (Expense):
Interest Income	0.5	0.2	0.8	0.5
Carrying Costs Income	0.3	1.0	0.6	0.2
Allowance for Equity Funds Used During Construction	2.0	2.3	3.5	4.6
Interest Expense	(48.2)	(47.3)	(96.3)	(94.3)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	82.0	114.5	256.2	313.7
Income Tax Expense (Credit)	29.9	41.1	93.5	114.0
Net Income (Loss)	52.1	73.4	162.7	199.7
Indiana Michigan Power Co [Member]
Revenues
Vertically Integrated Utilities	451.9	495.7	990.4	996.1
Other Revenues - Affiliated	12.4	22.4	31.1	49.2
Other Revenues	3.0	4.3	6.3	9.8
TOTAL REVENUES	467.3	522.4	1,027.8	1,055.1
Expenses
Fuel and Other Consumables Used for Electric Generation	71.1	76.3	161.8	145.5
Purchased Electricity for Resale	31.0	41.0	68.3	90.6
Purchased Electricity from AEP Affiliates	49.9	56.0	103.8	101.4
Other Operation	158.1	133.7	293.7	275.0
Maintenance	50.7	48.0	102.1	88.9
Depreciation and Amortization	49.8	47.0	99.8	94.1
Taxes Other Than Income Taxes	21.5	25.6	44.4	49.0
TOTAL EXPENSES	432.1	427.6	873.9	844.5
OPERATING INCOME (LOSS)	35.2	94.8	153.9	210.6
Other Income (Expense):
Interest Income	4.6	4.2	9.1	7.4
Allowance for Equity Funds Used During Construction	2.5	4.5	4.6	6.8
Interest Expense	(27.8)	(27.1)	(55.5)	(49.6)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	14.5	76.4	112.1	175.2
Income Tax Expense (Credit)	4.0	25.1	33.2	49.2
Net Income (Loss)	10.5	51.3	78.9	126.0
Ohio Power Co [Member]
Revenues
Transmission and Distribution Utilities	653.4	728.1	1,391.8	1,484.8
Sales to AEP Affiliates	9.1	1.4	14.8	6.2
Other Revenues	1.4	1.3	3.4	3.4
TOTAL REVENUES	663.9	730.8	1,410.0	1,494.4
Expenses
Purchased Electricity for Resale	156.4	147.8	344.7	312.7
Purchased Electricity from AEP Affiliates	24.7	36.4	56.7	85.5
Amortization of Generation Deferrals	53.3	51.8	114.2	106.9
Other Operation	130.6	173.8	251.8	341.7
Maintenance	33.3	31.9	70.5	65.6
Depreciation and Amortization	51.1	58.3	108.4	119.6
Taxes Other Than Income Taxes	94.9	92.2	193.4	189.8
TOTAL EXPENSES	544.3	592.2	1,139.7	1,221.8
OPERATING INCOME (LOSS)	119.6	138.6	270.3	272.6
Other Income (Expense):
Interest Income	0.8	0.8	3.3	2.3
Carrying Costs Income	0.6	1.2	2.5	3.1
Allowance for Equity Funds Used During Construction	0.8	1.7	3.2	3.4
Interest Expense	(26.1)	(29.1)	(51.1)	(60.5)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	95.7	113.2	228.2	220.9
Income Tax Expense (Credit)	33.4	38.6	79.7	76.1
Net Income (Loss)	62.3	74.6	148.5	144.8
Public Service Co Of Oklahoma [Member]
Revenues
Vertically Integrated Utilities	342.6	298.6	644.5	570.4
Sales to AEP Affiliates	1.0	0.9	2.1	1.9
Other Revenues	1.1	0.7	2.2	2.2
TOTAL REVENUES	344.7	300.2	648.8	574.5
Expenses
Fuel and Other Consumables Used for Electric Generation	25.6	11.1	37.9	26.6
Purchased Electricity for Resale	126.7	91.2	252.0	184.5
Purchased Electricity from AEP Affiliates	0.0	0.4	0.0	0.4
Other Operation	75.3	67.9	142.7	130.8
Maintenance	28.8	24.2	63.0	46.0
Depreciation and Amortization	32.6	37.4	66.1	72.7
Taxes Other Than Income Taxes	9.6	9.0	20.2	18.7
TOTAL EXPENSES	298.6	241.2	581.9	479.7
OPERATING INCOME (LOSS)	46.1	59.0	66.9	94.8
Other Income (Expense):
Interest Income	0.0	0.1	0.1	0.3
Allowance for Equity Funds Used During Construction	0.0	1.5	0.4	3.8
Interest Expense	(13.4)	(15.3)	(27.0)	(29.7)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	32.7	45.3	40.4	69.2
Income Tax Expense (Credit)	12.3	16.4	15.2	24.6
Net Income (Loss)	20.4	28.9	25.2	44.6
Southwestern Electric Power Co [Member]
Revenues
Vertically Integrated Utilities	416.0	418.2	812.3	793.6
Sales to AEP Affiliates	8.1	8.3	12.7	11.4
Other Revenues	0.6	0.5	1.0	1.0
TOTAL REVENUES	424.7	427.0	826.0	806.0
Expenses
Fuel and Other Consumables Used for Electric Generation	111.4	122.6	242.3	244.5
Purchased Electricity for Resale	46.3	33.5	78.7	61.6
Other Operation	73.9	77.0	151.9	154.1
Maintenance	41.7	37.1	73.9	68.2
Depreciation and Amortization	52.1	49.4	102.9	96.9
Taxes Other Than Income Taxes	24.3	21.5	47.6	43.4
TOTAL EXPENSES	349.7	341.1	697.3	668.7
OPERATING INCOME (LOSS)	75.0	85.9	128.7	137.3
Other Income (Expense):
Interest Income	0.4	0.0	1.3	0.0
Allowance for Equity Funds Used During Construction	0.0	2.0	0.8	9.4
Interest Expense	(30.9)	(31.5)	(60.8)	(59.4)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	44.5	56.4	70.0	87.3
Income Tax Expense (Credit)	13.2	13.3	22.7	20.7
Equity Earnings (Loss) of Unconsolidated Subsidiaries	(6.2)	1.2	(4.9)	2.2
Net Income (Loss)	25.1	44.3	42.4	68.8
Net Income Attributable to Noncontrolling Interests	0.6	1.1	1.6	2.2
Earnings Attributable to Common Shareholders	$ 24.5	$ 43.2	$ 40.8	$ 66.6