Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues
Vertically Integrated Utilities	$ 2,453.8	$ 2,538.3	$ 6,819.3	$ 6,864.6
Transmission and Distribution Utilities	1,149.7	1,245.4	3,242.7	3,398.9
Generation & Marketing	441.5	823.3	1,386.8	2,192.5
Sales to AEP Affiliates	0.0	0.0	0.0	0.0
Other Revenues	59.7	45.2	165.7	134.0
TOTAL REVENUES	4,104.7	4,652.2	11,614.5	12,590.0
Expenses
Fuel and Other Consumables Used for Electric Generation	707.4	880.1	1,865.3	2,236.1
Purchased Electricity for Resale	718.1	774.0	2,156.9	2,134.6
Other Operation	636.1	771.1	1,842.5	2,150.7
Maintenance	268.0	286.3	859.4	854.4
Asset Impairments and Other Related Charges	(2.5)	2,264.9	10.6	2,264.9
Gain on Sale of Merchant Generation Assets	0.0	0.0	(226.4)	0.0
Depreciation and Amortization	518.5	539.3	1,485.9	1,550.2
Taxes Other Than Income Taxes	272.6	264.4	792.0	767.9
TOTAL EXPENSES	3,118.2	5,780.1	8,786.2	11,958.8
OPERATING INCOME (LOSS)	986.5	(1,127.9)	2,828.3	631.2
Other Income (Expense):
Interest and Investment Income	2.4	2.0	12.7	6.5
Carrying Costs Income	2.6	1.7	14.2	11.9
Allowance for Equity Funds Used During Construction	20.0	25.6	62.2	86.1
Gain on Sale of Equity Investment	12.4	0.0	12.4	0.0
Interest Expense	(223.3)	(225.3)	(668.0)	(667.2)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	800.6	(1,323.9)	2,261.8	68.5
Income Tax Expense (Credit)	264.0	(534.5)	797.8	(134.0)
Equity Earnings (Loss) of Unconsolidated Subsidiaries	20.1	25.2	63.1	42.8
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	556.7	(764.2)	1,527.1	245.3
Income (Loss) from Discontinued Operations, Net of Tax	0.0	0.0	0.0	(2.5)
Net Income (Loss)	556.7	(764.2)	1,527.1	242.8
Net Income Attributable to Noncontrolling Interests	12.0	1.6	15.2	5.3
Earnings Attributable to Common Shareholders	$ 544.7	$ (765.8)	$ 1,511.9	$ 237.5
Earnings Per Share
Weighted Average Number of Basic AEP Common Shares Outstanding	491,840,722	491,697,809	491,781,643	491,422,921
Basic Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ 1.11	$ (1.56)	$ 3.07	$ 0.49
Basic Earnings Per Share Attributable to AEP Common Shareholders from Discontinued Operations	0.00	0.00	0.00	(0.01)
Total Basic Earnings Per Share Attributable to AEP Common Shareholders	$ 1.11	$ (1.56)	$ 3.07	$ 0.48
Weighted Average Number of Diluted AEP Common Shares Outstanding	492,986,307	491,813,858	492,428,586	491,596,861
Diluted Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ 1.10	$ (1.56)	$ 3.07	$ 0.49
Diluted Earnings Per Share Attributable to AEP Common Shareholders from Discontinued Operations	0.00	0.00	0.00	(0.01)
Total Diluted Earnings Per Share Attributable to AEP Common Shareholders	1.10	(1.56)	3.07	0.48
Common Stock, Dividends Per Share, Declared	$ 0.59	$ 0.56	$ 1.77	$ 1.68
AEP Transmission Co [Member]
Revenues
Electrical Transmission Revenue	$ 35.9	$ 33.5	$ 99.2	$ 89.6
Sales to AEP Affiliates	131.4	91.8	450.2	268.4
TOTAL REVENUES	167.3	125.3	549.4	358.0
Expenses
Other Operation	18.4	7.5	38.8	21.0
Maintenance	1.4	1.9	6.8	4.8
Depreciation and Amortization	24.8	16.8	70.9	47.5
Taxes Other Than Income Taxes	27.6	22.7	82.0	65.4
TOTAL EXPENSES	72.2	48.9	198.5	138.7
OPERATING INCOME (LOSS)	95.1	76.4	350.9	219.3
Other Income (Expense):
Interest Income	0.2	0.1	0.5	0.2
Allowance for Equity Funds Used During Construction	11.7	13.3	36.0	39.7
Interest Expense	(16.9)	(11.0)	(48.6)	(32.3)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	90.1	78.8	338.8	226.9
Income Tax Expense (Credit)	30.2	26.4	114.5	73.9
Net Income (Loss)	59.9	52.4	224.3	153.0
Appalachian Power Co [Member]
Revenues
Vertically Integrated Utilities	674.4	739.0	2,045.0	2,153.3
Sales to AEP Affiliates	41.9	36.4	130.6	109.0
Other Revenues	3.0	2.8	11.8	9.4
TOTAL REVENUES	719.3	778.2	2,187.4	2,271.7
Expenses
Fuel and Other Consumables Used for Electric Generation	178.6	190.1	498.3	494.1
Purchased Electricity for Resale	61.1	69.2	217.1	240.9
Other Operation	115.7	117.6	366.2	349.4
Maintenance	55.8	66.8	187.8	196.3
Depreciation and Amortization	102.8	98.1	304.1	290.0
Taxes Other Than Income Taxes	32.3	32.0	93.3	93.9
TOTAL EXPENSES	546.3	573.8	1,666.8	1,664.6
OPERATING INCOME (LOSS)	173.0	204.4	520.6	607.1
Other Income (Expense):
Interest Income	0.3	0.3	1.1	0.8
Carrying Costs Income	0.4	0.0	1.0	0.2
Allowance for Equity Funds Used During Construction	2.7	4.5	6.2	9.1
Interest Expense	(47.2)	(46.4)	(143.5)	(140.7)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	129.2	162.8	385.4	476.5
Income Tax Expense (Credit)	43.2	58.7	136.7	172.7
Net Income (Loss)	86.0	104.1	248.7	303.8
Indiana Michigan Power Co [Member]
Revenues
Vertically Integrated Utilities	537.0	574.7	1,527.4	1,570.8
Other Revenues - Affiliated	17.1	19.5	48.2	68.7
Other Revenues	3.6	3.4	9.9	13.2
TOTAL REVENUES	557.7	597.6	1,585.5	1,652.7
Expenses
Fuel and Other Consumables Used for Electric Generation	76.4	91.3	238.2	236.8
Purchased Electricity for Resale	32.9	43.7	101.2	134.3
Purchased Electricity from AEP Affiliates	62.4	64.5	166.2	165.9
Other Operation	140.5	138.9	434.2	413.9
Maintenance	51.5	45.7	153.6	134.6
Asset Impairments and Other Related Charges	0.0	10.5	0.0	10.5
Depreciation and Amortization	55.0	49.1	154.8	143.2
Taxes Other Than Income Taxes	23.9	22.5	68.3	71.5
TOTAL EXPENSES	442.6	466.2	1,316.5	1,310.7
OPERATING INCOME (LOSS)	115.1	131.4	269.0	342.0
Other Income (Expense):
Interest Income	2.4	1.7	11.5	9.1
Allowance for Equity Funds Used During Construction	3.5	4.1	8.1	10.9
Interest Expense	(27.5)	(26.7)	(83.0)	(76.3)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	93.5	110.5	205.6	285.7
Income Tax Expense (Credit)	28.6	35.1	61.8	84.3
Net Income (Loss)	64.9	75.4	143.8	201.4
Ohio Power Co [Member]
Revenues
Transmission and Distribution Utilities	736.0	864.4	2,127.8	2,349.2
Sales to AEP Affiliates	4.6	5.5	19.4	11.7
Other Revenues	1.4	1.4	4.8	4.8
TOTAL REVENUES	742.0	871.3	2,152.0	2,365.7
Expenses
Purchased Electricity for Resale	180.7	203.4	525.4	516.1
Purchased Electricity from AEP Affiliates	26.7	35.9	83.4	121.4
Amortization of Generation Deferrals	58.7	66.1	172.9	173.0
Other Operation	125.8	184.2	377.6	525.9
Maintenance	37.9	38.8	108.4	104.4
Depreciation and Amortization	57.3	69.4	165.7	189.0
Taxes Other Than Income Taxes	100.4	101.9	293.8	291.7
TOTAL EXPENSES	587.5	699.7	1,727.2	1,921.5
OPERATING INCOME (LOSS)	154.5	171.6	424.8	444.2
Other Income (Expense):
Interest Income	0.7	0.7	4.0	3.0
Carrying Costs Income	0.5	0.9	3.0	4.0
Allowance for Equity Funds Used During Construction	0.9	0.3	4.1	3.7
Interest Expense	(25.7)	(27.2)	(76.8)	(87.7)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	130.9	146.3	359.1	367.2
Income Tax Expense (Credit)	48.3	46.4	128.0	122.5
Net Income (Loss)	82.6	99.9	231.1	244.7
Public Service Co Of Oklahoma [Member]
Revenues
Vertically Integrated Utilities	440.6	400.9	1,085.1	971.3
Sales to AEP Affiliates	1.1	0.1	3.2	2.0
Other Revenues	1.1	0.7	3.3	2.9
TOTAL REVENUES	442.8	401.7	1,091.6	976.2
Expenses
Fuel and Other Consumables Used for Electric Generation	77.9	16.4	115.8	43.0
Purchased Electricity for Resale	127.8	130.8	379.8	315.3
Purchased Electricity from AEP Affiliates	0.0	3.2	0.0	3.6
Other Operation	83.6	81.0	226.3	211.8
Maintenance	25.2	25.6	88.2	71.6
Depreciation and Amortization	31.7	37.2	97.8	109.9
Taxes Other Than Income Taxes	9.8	9.1	30.0	27.8
TOTAL EXPENSES	356.0	303.3	937.9	783.0
OPERATING INCOME (LOSS)	86.8	98.4	153.7	193.2
Other Income (Expense):
Interest Income	0.0	0.2	0.1	0.5
Allowance for Equity Funds Used During Construction	0.0	1.1	0.4	4.9
Interest Expense	(13.2)	(14.9)	(40.2)	(44.6)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	73.6	84.8	114.0	154.0
Income Tax Expense (Credit)	27.4	32.0	42.6	56.6
Net Income (Loss)	46.2	52.8	71.4	97.4
Southwestern Electric Power Co [Member]
Revenues
Vertically Integrated Utilities	509.5	530.5	1,321.8	1,324.1
Sales to AEP Affiliates	7.7	8.6	20.4	20.0
Other Revenues	0.4	0.6	1.4	1.6
TOTAL REVENUES	517.6	539.7	1,343.6	1,345.7
Expenses
Fuel and Other Consumables Used for Electric Generation	147.5	158.8	389.8	403.3
Purchased Electricity for Resale	40.0	35.9	118.7	97.5
Other Operation	80.3	89.2	232.2	243.3
Maintenance	32.6	33.8	106.5	102.0
Depreciation and Amortization	55.2	51.2	158.1	148.1
Taxes Other Than Income Taxes	25.0	23.4	72.6	66.8
TOTAL EXPENSES	380.6	392.3	1,077.9	1,061.0
OPERATING INCOME (LOSS)	137.0	147.4	265.7	284.7
Other Income (Expense):
Interest Income	0.7	0.0	2.0	0.0
Allowance for Equity Funds Used During Construction	0.4	0.1	1.2	9.5
Interest Expense	(31.9)	(32.6)	(92.7)	(92.0)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAX EXPENSE (CREDIT) AND EQUITY EARNINGS (LOSS)	106.2	114.9	176.2	202.2
Income Tax Expense (Credit)	22.5	33.2	45.2	53.9
Equity Earnings (Loss) of Unconsolidated Subsidiaries	0.4	2.7	(4.5)	4.9
Net Income (Loss)	84.1	84.4	126.5	153.2
Net Income Attributable to Noncontrolling Interests	11.0	1.1	12.6	3.3
Earnings Attributable to Common Shareholders	$ 73.1	$ 83.3	$ 113.9	$ 149.9