Condensed Consolidated Balance Sheets - USD ($) $ in Millions		Jun. 30, 2017	Dec. 31, 2016
Current Assets
Cash and Cash Equivalents		$ 172.4	$ 210.5
Other Temporary Investments		317.6	331.7
Accounts Receivable:
Customers		538.7	705.1
Accrued Unbilled Revenues		122.1	158.7
Pledged Accounts Receivable - AEP Credit		949.4	972.7
Miscellaneous		90.5	118.1
Allowance for Uncollectible Accounts		(38.9)	(37.9)
Total Accounts Receivable		1,661.8	1,916.7
Fuel		427.2	423.8
Materials and Supplies		555.0	543.5
Risk Management Assets		170.5	94.5
Regulatory Asset for Under-Recovered Fuel Costs		189.0	156.6
Margin Deposits		91.1	79.9
Assets Held for Sale		0.0	1,951.2
Prepayments and Other Current Assets		224.4	325.5
TOTAL CURRENT ASSETS		3,809.0	6,033.9
Property, Plant and Equipment
Generation		20,354.2	19,848.9
Transmission		17,481.2	16,658.7
Distribution		19,367.0	18,900.8
Other Property, Plant and Equipment		3,595.6	3,444.3
Construction Work in Progress		3,336.8	3,183.9
Total Property, Plant and Equipment		64,134.8	62,036.6
Accumulated Depreciation and Amortization		16,907.6	16,397.3
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		47,227.2	45,639.3
Other Noncurrent Assets
Regulatory Assets		5,592.6	5,625.5
Securitized Assets		1,364.4	1,486.1
Spent Nuclear Fuel and Decommissioning Trusts		2,382.0	2,256.2
Goodwill		52.5	52.5
Long-term Risk Management Assets		285.6	289.1
Deferred Charges and Other Noncurrent Assets		2,025.8	2,085.1
TOTAL OTHER NONCURRENT ASSETS		11,702.9	11,794.5
TOTAL ASSETS		62,739.1	63,467.7
Current Liabilities
Accounts Payable		1,268.4	1,688.5
Short-term Debt:
Securitized Debt for Receivables - AEP Credit	[1]	519.0	673.0
Other Short-term Debt		1,332.7	1,040.0
Total Short-term Debt		1,851.7	1,713.0
Long-term Debt Due Within One Year		2,755.0	2,878.0
Risk Management Liabilities		61.7	53.4
Customer Deposits		344.0	343.2
Accrued Taxes		891.5	1,048.0
Accrued Interest		217.0	227.2
Regulatory Liability for Over-Recovered Fuel Costs		17.1	8.0
Liabilities Held for Sale		0.0	235.9
Other Current Liabilities		985.8	1,302.8
TOTAL CURRENT LIABILITIES		8,392.2	9,498.0
Noncurrent Liabilities
Long-term Debt		16,796.9	17,378.4
Long-term Risk Management Liabilities		310.6	316.2
Deferred Income Taxes		12,288.5	11,884.4
Regulatory Liabilities and Deferred Investment Tax Credits		3,908.8	3,751.3
Asset Retirement Obligations		1,911.0	1,830.6
Employee Benefits and Pension Obligations		462.8	614.1
Deferred Credits and Other Noncurrent Liabilities		813.3	774.6
TOTAL NONCURRENT LIABILITIES		36,491.9	36,549.6
TOTAL LIABILITIES		44,884.1	46,047.6
Rate Matters
Commitments and Contingencies
Mezzanine Equity		5.5	0.0
Equity
Common Stock		3,328.3	3,328.3
Paid-in Capital		6,381.0	6,332.6
Retained Earnings		8,276.4	7,892.4
Accumulated Other Comprehensive Income (Loss)		(161.6)	(156.3)
TOTAL COMMON SHAREHOLDER'S EQUITY		17,824.1	17,397.0
Noncontrolling Interests		25.4	23.1
TOTAL EQUITY		17,849.5	17,420.1
TOTAL LIABILITIES AND EQUITY		62,739.1	63,467.7
AEP Transmission Co [Member]
Current Assets
Cash and Cash Equivalents		0.0	0.0
Advances to Affiliates		22.2	67.1
Accounts Receivable:
Customers		20.5	11.3
Affiliated Companies		94.4	66.6
Total Accounts Receivable		114.9	77.9
Materials and Supplies		10.9	5.0
Accrued Tax Benefits		10.4	26.0
Prepayments and Other Current Assets		7.5	2.8
TOTAL CURRENT ASSETS		165.9	178.8
Property, Plant and Equipment
Transmission		4,383.9	3,973.5
Other Property, Plant and Equipment		109.4	99.4
Construction Work in Progress		1,197.0	981.3
Total Property, Plant and Equipment		5,690.3	5,054.2
Accumulated Depreciation and Amortization		133.1	99.6
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		5,557.2	4,954.6
Other Noncurrent Assets
Accounts Receivable, Related Parties, Noncurrent		27.6	0.0
Regulatory Assets		133.5	112.3
Deferred Tax Assets, Property, Plant and Equipment		58.1	102.2
Deferred Charges and Other Noncurrent Assets		1.3	1.9
TOTAL OTHER NONCURRENT ASSETS		220.5	216.4
TOTAL ASSETS		5,943.6	5,349.8
Current Liabilities
Advances from Affiliates		247.4	4.1
Accounts Payable		178.1	289.7
Affiliated Companies		45.8	43.1
Short-term Debt:
Accrued Taxes		149.1	191.8
Accrued Interest		9.8	10.5
Other Current Liabilities		9.9	10.9
TOTAL CURRENT LIABILITIES		640.1	550.1
Noncurrent Liabilities
Long-term Debt		1,931.4	1,932.0
Deferred Income Taxes		1,008.2	862.1
Regulatory Liabilities and Deferred Investment Tax Credits		54.5	44.0
Deferred Credits and Other Noncurrent Liabilities		20.7	4.0
TOTAL NONCURRENT LIABILITIES		3,014.8	2,842.1
TOTAL LIABILITIES		3,654.9	3,392.2
Rate Matters
Commitments and Contingencies
Equity
Paid-in Captial		1,621.7	1,455.0
Retained Earnings		667.0	502.6
TOTAL MEMBER'S EQUITY		2,288.7	1,957.6
TOTAL LIABILITIES AND EQUITY		5,943.6	5,349.8
Appalachian Power Co [Member]
Current Assets
Cash and Cash Equivalents		2.6	2.7
Restricted Cash for Securitized Funding		15.4	15.8
Advances to Affiliates		23.8	24.1
Accounts Receivable:
Customers		106.9	131.4
Affiliated Companies		61.7	54.4
Accrued Unbilled Revenues		44.2	52.7
Miscellaneous		1.8	0.9
Allowance for Uncollectible Accounts		(2.7)	(3.5)
Total Accounts Receivable		211.9	235.9
Fuel		110.4	112.0
Materials and Supplies		100.3	98.8
Risk Management Assets		41.6	2.6
Accrued Tax Benefits		6.2	4.2
Regulatory Asset for Under-Recovered Fuel Costs		72.4	68.4
Margin Deposits		6.3	17.5
Prepayments and Other Current Assets		12.7	9.7
TOTAL CURRENT ASSETS		603.6	591.7
Property, Plant and Equipment
Generation		6,389.0	6,332.8
Transmission		2,873.6	2,796.9
Distribution		3,657.6	3,569.1
Other Property, Plant and Equipment		403.2	373.5
Construction Work in Progress		397.8	390.3
Total Property, Plant and Equipment		13,721.2	13,462.6
Accumulated Depreciation and Amortization		3,762.8	3,636.8
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		9,958.4	9,825.8
Other Noncurrent Assets
Regulatory Assets		1,106.9	1,121.1
Securitized Assets		293.7	305.3
Deferred Charges and Other Noncurrent Assets		131.3	133.3
TOTAL OTHER NONCURRENT ASSETS		1,531.9	1,559.7
TOTAL ASSETS		12,093.9	11,977.2
Current Liabilities
Advances from Affiliates		124.7	79.6
Accounts Payable		212.5	253.7
Affiliated Companies		102.3	82.6
Short-term Debt:
Long-term Debt Due Within One Year		149.0	503.1
Risk Management Liabilities		0.4	0.3
Customer Deposits		83.1	83.1
Accrued Taxes		78.2	107.6
Accrued Interest		41.0	40.6
Other Current Liabilities		107.3	129.5
TOTAL CURRENT LIABILITIES		898.5	1,280.1
Noncurrent Liabilities
Long-term Debt		3,841.5	3,530.8
Long-term Risk Management Liabilities		0.4	0.9
Deferred Income Taxes		2,756.3	2,672.3
Regulatory Liabilities and Deferred Investment Tax Credits		633.2	627.8
Asset Retirement Obligations		107.5	108.8
Employee Benefits and Pension Obligations		92.2	108.5
Deferred Credits and Other Noncurrent Liabilities		79.1	64.5
TOTAL NONCURRENT LIABILITIES		7,510.2	7,113.6
TOTAL LIABILITIES		8,408.7	8,393.7
Rate Matters
Commitments and Contingencies
Equity
Common Stock		260.4	260.4
Paid-in Capital		1,828.7	1,828.7
Retained Earnings		1,605.5	1,502.8
Accumulated Other Comprehensive Income (Loss)		(9.4)	(8.4)
TOTAL EQUITY		3,685.2	3,583.5
TOTAL LIABILITIES AND EQUITY		12,093.9	11,977.2
Indiana Michigan Power Co [Member]
Current Assets
Cash and Cash Equivalents		1.1	1.2
Advances to Affiliates		12.6	12.5
Accounts Receivable:
Customers		22.4	60.2
Affiliated Companies		56.9	51.0
Accrued Unbilled Revenues		0.0	1.5
Miscellaneous		0.7	0.7
Allowance for Uncollectible Accounts		(0.1)	0.0
Total Accounts Receivable		79.9	113.4
Fuel		41.5	32.3
Materials and Supplies		157.8	150.8
Risk Management Assets		15.8	3.5
Accrued Tax Benefits		19.4	37.7
Regulatory Asset for Under-Recovered Fuel Costs		10.9	26.1
Accrued Reimbursement of Spent Nuclear Fuel Costs		14.8	22.1
Prepayments and Other Current Assets		19.0	19.9
TOTAL CURRENT ASSETS		372.8	419.5
Property, Plant and Equipment
Generation		4,227.8	4,056.1
Transmission		1,487.3	1,472.8
Distribution		1,965.6	1,899.3
Other Property, Plant and Equipment		571.6	550.2
Construction Work in Progress		592.4	654.2
Total Property, Plant and Equipment		8,844.7	8,632.6
Accumulated Depreciation and Amortization		3,014.1	3,005.1
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		5,830.6	5,627.5
Other Noncurrent Assets
Regulatory Assets		901.6	916.6
Spent Nuclear Fuel and Decommissioning Trusts		2,382.0	2,256.2
Deferred Charges and Other Noncurrent Assets		104.0	121.5
TOTAL OTHER NONCURRENT ASSETS		3,387.6	3,294.3
TOTAL ASSETS		9,591.0	9,341.3
Current Liabilities
Advances from Affiliates		43.4	215.2
Accounts Payable		173.6	179.0
Affiliated Companies		107.2	75.6
Short-term Debt:
Long-term Debt Due Within One Year		479.8	209.3
Risk Management Liabilities		0.9	0.3
Customer Deposits		36.6	34.3
Accrued Taxes		71.9	77.2
Accrued Interest		31.8	31.7
Obligations Under Capital Leases		8.3	9.4
Other Current Liabilities		99.7	123.4
TOTAL CURRENT LIABILITIES		1,053.2	955.4
Noncurrent Liabilities
Long-term Debt		2,211.6	2,262.1
Long-term Risk Management Liabilities		0.2	0.8
Deferred Income Taxes		1,610.2	1,527.4
Regulatory Liabilities and Deferred Investment Tax Credits		1,144.4	1,065.5
Asset Retirement Obligations		1,293.3	1,257.9
Deferred Credits and Other Noncurrent Liabilities		109.2	120.4
TOTAL NONCURRENT LIABILITIES		6,368.9	6,234.1
TOTAL LIABILITIES		7,422.1	7,189.5
Rate Matters
Commitments and Contingencies
Equity
Common Stock		56.6	56.6
Paid-in Capital		980.9	980.9
Retained Earnings		1,146.9	1,130.5
Accumulated Other Comprehensive Income (Loss)		(15.5)	(16.2)
TOTAL EQUITY		2,168.9	2,151.8
TOTAL LIABILITIES AND EQUITY		9,591.0	9,341.3
Ohio Power Co [Member]
Current Assets
Cash and Cash Equivalents		2.2	3.1
Restricted Cash for Securitized Funding		27.3	27.2
Advances to Affiliates		0.0	24.2
Accounts Receivable:
Customers		55.4	51.1
Affiliated Companies		61.2	66.3
Accrued Unbilled Revenues		5.2	21.0
Miscellaneous		1.3	0.9
Allowance for Uncollectible Accounts		(2.5)	(0.4)
Total Accounts Receivable		120.6	138.9
Materials and Supplies		43.2	45.9
Emission Allowances		21.9	20.4
Risk Management Assets		0.0	0.2
Accrued Tax Benefits		47.9	0.1
Prepayments and Other Current Assets		20.6	10.9
TOTAL CURRENT ASSETS		283.7	270.9
Property, Plant and Equipment
Transmission		2,337.7	2,319.2
Distribution		4,536.2	4,457.2
Other Property, Plant and Equipment		482.2	443.7
Construction Work in Progress		285.1	221.5
Total Property, Plant and Equipment		7,641.2	7,441.6
Accumulated Depreciation and Amortization		2,164.3	2,116.0
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		5,476.9	5,325.6
Other Noncurrent Assets
Notes Receivable - Affiliated		32.3	32.3
Regulatory Assets		1,058.0	1,107.5
Securitized Assets		49.6	62.1
Deferred Charges and Other Noncurrent Assets		191.4	295.5
TOTAL OTHER NONCURRENT ASSETS		1,331.3	1,497.4
TOTAL ASSETS		7,091.9	7,093.9
Current Liabilities
Advances from Affiliates		190.5	0.0
Accounts Payable		150.1	175.4
Affiliated Companies		120.4	95.6
Short-term Debt:
Long-term Debt Due Within One Year		396.8	46.4
Risk Management Liabilities		7.1	5.9
Customer Deposits		67.1	71.0
Accrued Taxes		315.6	520.3
Accrued Interest		31.1	31.2
Other Current Liabilities		185.1	236.0
TOTAL CURRENT LIABILITIES		1,463.8	1,181.8
Noncurrent Liabilities
Long-term Debt		1,345.7	1,717.5
Long-term Risk Management Liabilities		123.5	113.1
Deferred Income Taxes		1,438.7	1,346.1
Regulatory Liabilities and Deferred Investment Tax Credits		521.2	506.2
Employee Benefits and Pension Obligations		19.5	27.8
Deferred Credits and Other Noncurrent Liabilities		44.0	83.9
TOTAL NONCURRENT LIABILITIES		3,492.6	3,794.6
TOTAL LIABILITIES		4,956.4	4,976.4
Rate Matters
Commitments and Contingencies
Equity
Common Stock		321.2	321.2
Paid-in Capital		838.8	838.8
Retained Earnings		973.0	954.5
Accumulated Other Comprehensive Income (Loss)		2.5	3.0
TOTAL EQUITY		2,135.5	2,117.5
TOTAL LIABILITIES AND EQUITY		7,091.9	7,093.9
Public Service Co Of Oklahoma [Member]
Current Assets
Cash and Cash Equivalents		1.4	1.5
Accounts Receivable:
Customers		23.7	27.5
Affiliated Companies		27.4	26.8
Miscellaneous		2.0	4.4
Allowance for Uncollectible Accounts		(0.2)	(0.2)
Total Accounts Receivable		52.9	58.5
Fuel		15.5	22.9
Materials and Supplies		43.8	44.6
Risk Management Assets		9.5	0.8
Accrued Tax Benefits		22.8	27.3
Regulatory Asset for Under-Recovered Fuel Costs		63.4	33.8
Prepayments and Other Current Assets		7.6	6.0
TOTAL CURRENT ASSETS		216.9	195.4
Property, Plant and Equipment
Generation		1,572.2	1,559.3
Transmission		846.0	832.8
Distribution		2,390.2	2,322.4
Other Property, Plant and Equipment		283.9	233.2
Construction Work in Progress		111.2	148.2
Total Property, Plant and Equipment		5,203.5	5,095.9
Accumulated Depreciation and Amortization		1,362.9	1,272.7
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		3,840.6	3,823.2
Other Noncurrent Assets
Regulatory Assets		391.7	340.2
Employee Benefits and Pension Assets		15.9	10.4
Deferred Charges and Other Noncurrent Assets		28.5	10.0
TOTAL OTHER NONCURRENT ASSETS		436.1	360.6
TOTAL ASSETS		4,493.6	4,379.2
Current Liabilities
Advances from Affiliates		141.4	52.0
Accounts Payable		104.2	116.3
Affiliated Companies		73.8	56.2
Short-term Debt:
Long-term Debt Due Within One Year		0.5	0.5
Customer Deposits		52.5	49.7
Accrued Taxes		40.5	21.0
Accrued Interest		13.4	13.9
Provision for Refund		22.8	46.1
Other Current Liabilities		41.8	47.8
TOTAL CURRENT LIABILITIES		490.9	403.5
Noncurrent Liabilities
Long-term Debt		1,285.8	1,285.5
Deferred Income Taxes		1,112.5	1,058.8
Regulatory Liabilities and Deferred Investment Tax Credits		325.5	339.7
Asset Retirement Obligations		53.9	52.8
Deferred Credits and Other Noncurrent Liabilities		21.1	24.8
TOTAL NONCURRENT LIABILITIES		2,798.8	2,761.6
TOTAL LIABILITIES		3,289.7	3,165.1
Rate Matters
Commitments and Contingencies
Equity
Common Stock		157.2	157.2
Paid-in Capital		364.0	364.0
Retained Earnings		679.7	689.5
Accumulated Other Comprehensive Income (Loss)		3.0	3.4
TOTAL EQUITY		1,203.9	1,214.1
TOTAL LIABILITIES AND EQUITY		4,493.6	4,379.2
Southwestern Electric Power Co [Member]
Current Assets
Cash and Cash Equivalents		1.7	10.3
Advances to Affiliates		2.0	169.8
Accounts Receivable:
Customers		20.5	48.5
Affiliated Companies		35.2	29.3
Miscellaneous		17.3	17.5
Allowance for Uncollectible Accounts		(0.9)	(1.2)
Total Accounts Receivable		72.1	94.1
Fuel		103.1	107.1
Materials and Supplies		69.3	68.4
Risk Management Assets		12.5	0.9
Accrued Tax Benefits		40.4	51.5
Regulatory Asset for Under-Recovered Fuel Costs		13.9	8.4
Prepayments and Other Current Assets		26.4	35.5
TOTAL CURRENT ASSETS		341.4	546.0
Property, Plant and Equipment
Generation		4,618.7	4,607.6
Transmission		1,648.5	1,584.2
Distribution		2,061.0	2,020.6
Other Property, Plant and Equipment		699.3	670.4
Construction Work in Progress		116.1	113.8
Total Property, Plant and Equipment		9,143.6	8,996.6
Accumulated Depreciation and Amortization		2,634.4	2,567.1
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		6,509.2	6,429.5
Other Noncurrent Assets
Regulatory Assets		567.6	551.2
Deferred Charges and Other Noncurrent Assets		128.3	99.9
TOTAL OTHER NONCURRENT ASSETS		695.9	651.1
TOTAL ASSETS		7,546.5	7,626.6
Current Liabilities
Advances from Affiliates		58.6	0.0
Accounts Payable		126.7	117.5
Affiliated Companies		80.1	68.5
Short-term Debt:
Other Short-term Debt		8.7	0.0
Long-term Debt Due Within One Year		385.4	353.7
Risk Management Liabilities		0.5	0.3
Customer Deposits		62.2	62.1
Accrued Taxes		78.6	40.9
Accrued Interest		38.1	45.1
Obligations Under Capital Leases		11.3	11.8
Other Current Liabilities		70.5	83.9
TOTAL CURRENT LIABILITIES		920.7	783.8
Noncurrent Liabilities
Long-term Debt		2,057.3	2,325.4
Deferred Income Taxes		1,681.0	1,606.9
Regulatory Liabilities and Deferred Investment Tax Credits		440.5	438.9
Asset Retirement Obligations		154.5	147.1
Employee Benefits and Pension Obligations		19.2	34.1
Obligations Under Capital Leases		62.1	65.5
Deferred Credits and Other Noncurrent Liabilities		9.9	9.7
TOTAL NONCURRENT LIABILITIES		4,424.5	4,627.6
TOTAL LIABILITIES		5,345.2	5,411.4
Rate Matters
Commitments and Contingencies
Equity
Common Stock		135.7	135.7
Paid-in Capital		676.6	676.6
Retained Earnings		1,397.7	1,411.9
Accumulated Other Comprehensive Income (Loss)		(9.0)	(9.4)
TOTAL COMMON SHAREHOLDER'S EQUITY		2,201.0	2,214.8
Noncontrolling Interests		0.3	0.4
TOTAL EQUITY		2,201.3	2,215.2
TOTAL LIABILITIES AND EQUITY		$ 7,546.5	$ 7,626.6

[1] Amount of securitized debt for receivables as accounted for under the “Transfers and Servicing” accounting guidance.