Leases (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020	Dec. 31, 2019
Lease Rental Costs
Operating Lease, Cost		$ 275.3		$ 279.6	$ 286.0
Finance Lease Right-of-Use Asset Amortization		74.7		61.9	70.8
Interest Expense on Finance Leases		14.4		15.4	16.4
Total Lease Rental Costs	[1]	$ 364.4		$ 356.9	373.2
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases		10 years 4 months 20 days		5 years 3 months 18 days
Weighted Average Remaining Lease Term, Finance Leases		2 years 11 months 12 days		5 years 5 months 4 days
Weighted Average Discount Rate, Operating Leases		3.35%		3.44%
Weighted Average Discount Rate, Finance Leases		3.26%		5.68%
Operating Cash Flows Used for Operating Leases		$ 279.9		$ 280.3
Operating Cash Flows Used for Finance Leases		14.3		15.4
Financing Cash Flows Used for Finance Leases		64.0		61.7	70.7
Non-cash Acquisitions Under Operating Leases		117.0		161.7
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		23,088.1		23,133.9
Other Property, Plant and Equipment		5,682.9		5,294.6
Total Property, Plant and Equipment		86,806.4		84,313.0
Accumulated Amortization		20,805.1		20,411.4
Net Property, Plant and Equipment Under Finance Leases		490.2	[2]	284.2
Other Liabilities, Noncurrent		601.3		728.0
Finance Lease Liability Due Within One Year		1,369.2		1,251.9
Total Obligations Under Finance Leases		500.7	[3]	289.1
Operating Lease Asset and Related Obligations
Operating Lease Assets		578.3		866.4
Operating Lease Noncurrent Liability		492.8		638.4
Operating Lease Liability Due Within One Year		97.6		241.3
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		590.4	[4]	879.7
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		317.3
Year 2		61.0
Year 3		64.7
Year 4		35.6
Year 5		20.1
Finance Leases, Later Years		39.2
Finance Leases, Total Future Minimum Lease Payments		537.9
Imputed Interest on Finance Leases		37.2
Total Obligations Under Finance Leases		500.7	[3]	289.1
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		119.6
Year 2		102.2
Year 3		89.9
Year 4		76.7
Year 5		64.0
Operating Leases, Later Years		272.4
Operating Leases, Total Future Minimum Lease Payments		724.8
Imputed Interest on Operating Leases		134.4
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		590.4	[4]	879.7
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements		47.4
Leases (Textuals)
Assets Held for Sale		2,919.7		0.0
Liabilities Held for Sale		1,880.9		0.0
Liabilities Held for Sale		1,880.9		0.0
Kentucky Power Co [Member]
Leases (Textuals)
Liabilities Held for Sale		3.0
Liabilities Held for Sale		3.0
Kentucky Power Co [Member]
Leases (Textuals)
Assets Held for Sale		3.0
Kentucky Power Co [Member]
Leases (Textuals)
Liabilities Held for Sale		11.0
Liabilities Held for Sale		11.0
Kentucky Power Co [Member]
Leases (Textuals)
Assets Held for Sale		11.0
Rockport Lease [Member]
Future Minimum Rentals, Sale Leaseback Transactions
2022	[5]	248.7
Total Future Minimum Lease Payments	[5]	248.7
Boat and Barge Leases [Member]
Leases (Textuals)
Maximum Potential Lease Payments, AEPRO Barge and Boat Leases		42.0
Guarantor Obligations, Current Carrying Value		2.0
Guarantee Obligations Current Carrying Value Other Liabilities Current		1.0
Guarantee Obligations Current Carrying Value Other Liabilities Noncurrent		1.0
Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		388.8		138.2
Other Property, Plant and Equipment		323.8		322.8
Total Property, Plant and Equipment		712.6		461.0
Accumulated Amortization		222.4		176.8
Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent		196.1		231.0
Finance Lease Liability Due Within One Year		304.6		58.1
Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets		578.3	[6]	866.4
AEP Texas Inc. [Member]
Lease Rental Costs
Operating Lease, Cost		18.4		17.4	16.5
Finance Lease Right-of-Use Asset Amortization		6.7		6.3	5.1
Interest Expense on Finance Leases		1.4		1.5	1.4
Total Lease Rental Costs	[1]	$ 26.5		$ 25.2	23.0
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases		5 years 10 months 28 days		6 years 6 months 3 days
Weighted Average Remaining Lease Term, Finance Leases		5 years 6 months 3 days		6 years 25 days
Weighted Average Discount Rate, Operating Leases		3.53%		3.60%
Weighted Average Discount Rate, Finance Leases		4.31%		4.39%
Operating Cash Flows Used for Operating Leases		$ 18.0		$ 17.1
Operating Cash Flows Used for Finance Leases		1.4		1.5
Financing Cash Flows Used for Finance Leases		6.7		6.3	5.1
Non-cash Acquisitions Under Operating Leases		4.4		15.8
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Property, Plant and Equipment		961.1		868.4
Total Property, Plant and Equipment		12,279.5		11,342.9
Accumulated Amortization		1,644.1		1,529.3
Net Property, Plant and Equipment Under Finance Leases		30.8		33.1
Other Liabilities, Noncurrent		73.8		57.2
Finance Lease Liability Due Within One Year		78.0		108.6
Total Obligations Under Finance Leases		30.8		33.1
Operating Lease Asset and Related Obligations
Operating Lease Noncurrent Liability		61.3		71.0
Operating Lease Liability Due Within One Year		14.0		14.5
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		75.3		85.5
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		7.8
Year 2		7.1
Year 3		5.9
Year 4		4.5
Year 5		3.5
Finance Leases, Later Years		5.9
Finance Leases, Total Future Minimum Lease Payments		34.7
Imputed Interest on Finance Leases		3.9
Total Obligations Under Finance Leases		30.8		33.1
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		16.7
Year 2		15.5
Year 3		14.1
Year 4		11.7
Year 5		9.5
Operating Leases, Later Years		16.9
Operating Leases, Total Future Minimum Lease Payments		84.4
Imputed Interest on Operating Leases		9.1
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		75.3		85.5
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements		11.1
AEP Texas Inc. [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		0.0		0.0
Other Property, Plant and Equipment		50.7		49.7
Total Property, Plant and Equipment		50.7		49.7
Accumulated Amortization		19.9		16.6
AEP Texas Inc. [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent		24.2		26.8
Finance Lease Liability Due Within One Year		6.6		6.3
AEP Texas Inc. [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets		73.6		84.1
AEP Transmission Co [Member]
Lease Rental Costs
Operating Lease, Cost		1.7		2.6	2.5
Finance Lease Right-of-Use Asset Amortization		0.0		0.0	0.1
Interest Expense on Finance Leases		0.0		0.0	0.0
Total Lease Rental Costs	[1]	$ 1.7		$ 2.6	2.6
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases		2 years 11 months 12 days		2 years 3 days
Weighted Average Remaining Lease Term, Finance Leases		0 years		0 years
Weighted Average Discount Rate, Operating Leases		0.90%		1.51%
Weighted Average Discount Rate, Finance Leases		0.00%		0.00%
Operating Cash Flows Used for Operating Leases		$ 1.6		$ 2.6
Operating Cash Flows Used for Finance Leases		0.0		0.0
Financing Cash Flows Used for Finance Leases		0.0		0.0
Non-cash Acquisitions Under Operating Leases		2.1		1.8
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Property, Plant and Equipment		427.4		329.5
Total Property, Plant and Equipment		12,708.5		11,345.6
Accumulated Amortization		772.8		572.8
Net Property, Plant and Equipment Under Finance Leases		0.0		0.0
Other Liabilities, Noncurrent		3.2		8.0
Finance Lease Liability Due Within One Year		3.0		9.9
Total Obligations Under Finance Leases		0.0		0.0
Operating Lease Asset and Related Obligations
Operating Lease Noncurrent Liability		1.3		0.4
Operating Lease Liability Due Within One Year		0.9		1.2
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		2.2		1.6
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		0.0
Year 2		0.0
Year 3		0.0
Year 4		0.0
Year 5		0.0
Finance Leases, Later Years		0.0
Finance Leases, Total Future Minimum Lease Payments		0.0
Imputed Interest on Finance Leases		0.0
Total Obligations Under Finance Leases		0.0		0.0
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		0.9
Year 2		0.7
Year 3		0.4
Year 4		0.2
Year 5		0.0
Operating Leases, Later Years		0.0
Operating Leases, Total Future Minimum Lease Payments		2.2
Imputed Interest on Operating Leases		0.0
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		2.2		1.6
Leases (Textuals)
Assets Held for Sale		167.9		0.0
Liabilities Held for Sale		27.6		0.0
Liabilities Held for Sale		27.6		0.0
AEP Transmission Co [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		0.0		0.0
Other Property, Plant and Equipment		0.0		0.0
Total Property, Plant and Equipment		0.0		0.0
Accumulated Amortization		0.0		0.0
AEP Transmission Co [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent		0.0		0.0
Finance Lease Liability Due Within One Year		0.0		0.0
AEP Transmission Co [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets		2.0		1.6
Appalachian Power Co [Member]
Lease Rental Costs
Operating Lease, Cost		19.3		19.1	19.5
Finance Lease Right-of-Use Asset Amortization		7.7		7.4	6.7
Interest Expense on Finance Leases		2.4		2.7	2.9
Total Lease Rental Costs	[1]	$ 29.4		$ 29.2	29.1
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases		5 years 8 months 4 days		6 years 3 months 7 days
Weighted Average Remaining Lease Term, Finance Leases		4 years 11 months 19 days		5 years 9 months
Weighted Average Discount Rate, Operating Leases		3.42%		3.48%
Weighted Average Discount Rate, Finance Leases		7.16%		7.33%
Operating Cash Flows Used for Operating Leases		$ 19.3		$ 19.2
Operating Cash Flows Used for Finance Leases		2.4		2.7
Financing Cash Flows Used for Finance Leases		7.7		7.4	6.7
Non-cash Acquisitions Under Operating Leases		4.2		16.2
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		6,683.9		6,633.7
Other Property, Plant and Equipment		696.6		627.2
Total Property, Plant and Equipment		16,856.1		16,110.3
Accumulated Amortization		5,051.8		4,716.2
Net Property, Plant and Equipment Under Finance Leases		35.7		41.7
Other Liabilities, Noncurrent		34.6		49.6
Finance Lease Liability Due Within One Year		146.4		169.1
Total Obligations Under Finance Leases		35.7		41.7
Operating Lease Asset and Related Obligations
Operating Lease Assets		66.9		78.8
Operating Lease Noncurrent Liability		52.4		64.4
Operating Lease Liability Due Within One Year		15.1		14.9
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		67.5		79.3
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		9.8
Year 2		9.1
Year 3		8.3
Year 4		7.2
Year 5		2.7
Finance Leases, Later Years		4.1
Finance Leases, Total Future Minimum Lease Payments		41.2
Imputed Interest on Finance Leases		5.5
Total Obligations Under Finance Leases		35.7		41.7
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		17.5
Year 2		14.8
Year 3		11.9
Year 4		9.1
Year 5		7.2
Operating Leases, Later Years		14.1
Operating Leases, Total Future Minimum Lease Payments		74.6
Imputed Interest on Operating Leases		7.1
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		67.5		79.3
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements		6.2
Appalachian Power Co [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		42.8		42.8
Other Property, Plant and Equipment		20.4		20.3
Total Property, Plant and Equipment		63.2		63.1
Accumulated Amortization		27.5		21.4
Appalachian Power Co [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent		28.1		34.4
Finance Lease Liability Due Within One Year		7.6		7.3
Appalachian Power Co [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets		66.9		78.8
Indiana Michigan Power Co [Member]
Lease Rental Costs
Operating Lease, Cost		90.2		101.5	93.1
Finance Lease Right-of-Use Asset Amortization		12.9		6.5	5.7
Interest Expense on Finance Leases		3.0		3.1	2.9
Total Lease Rental Costs	[1]	$ 106.1		$ 111.1	101.7
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases		5 years 10 months 13 days		3 years 6 months
Weighted Average Remaining Lease Term, Finance Leases		2 years 1 month 6 days		5 years 9 months 14 days
Weighted Average Discount Rate, Operating Leases		3.46%		3.42%
Weighted Average Discount Rate, Finance Leases		3.02%		8.29%
Operating Cash Flows Used for Operating Leases		$ 92.9		$ 102.2
Operating Cash Flows Used for Finance Leases		2.9		3.1
Financing Cash Flows Used for Finance Leases		6.8		6.5	5.7
Non-cash Acquisitions Under Operating Leases		2.6		18.1
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		5,531.8		5,264.7
Other Property, Plant and Equipment		792.9		686.7
Total Property, Plant and Equipment		11,210.7		10,604.8
Accumulated Amortization		3,899.8		3,552.5
Net Property, Plant and Equipment Under Finance Leases		160.7		41.7
Other Liabilities, Noncurrent		58.3		69.2
Finance Lease Liability Due Within One Year		123.2		105.5
Total Obligations Under Finance Leases		162.2		41.7
Operating Lease Asset and Related Obligations
Operating Lease Assets		63.5		218.1
Operating Lease Noncurrent Liability		48.9		135.9
Operating Lease Liability Due Within One Year		15.5		85.6
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		64.4		221.5
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		133.7
Year 2		8.6
Year 3		11.6
Year 4		5.9
Year 5		3.5
Finance Leases, Later Years		10.1
Finance Leases, Total Future Minimum Lease Payments		173.4
Imputed Interest on Finance Leases		11.2
Total Obligations Under Finance Leases		162.2		41.7
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		17.6
Year 2		11.7
Year 3		10.4
Year 4		9.3
Year 5		7.3
Operating Leases, Later Years		15.0
Operating Leases, Total Future Minimum Lease Payments		71.3
Imputed Interest on Operating Leases		6.9
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		64.4		221.5
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements		4.1
Indiana Michigan Power Co [Member] | Rockport Lease [Member]
Future Minimum Rentals, Sale Leaseback Transactions
2022		124.4
Total Future Minimum Lease Payments		124.4
Indiana Michigan Power Co [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		156.8		28.8
Other Property, Plant and Equipment		42.1		40.2
Total Property, Plant and Equipment		198.9		69.0
Accumulated Amortization		38.2		27.3
Indiana Michigan Power Co [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent		31.7		35.3
Finance Lease Liability Due Within One Year		130.5		6.4
Indiana Michigan Power Co [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets		63.5		218.1
Ohio Power Co [Member]
Lease Rental Costs
Operating Lease, Cost		19.0		17.1	18.0
Finance Lease Right-of-Use Asset Amortization		4.9		4.7	3.5
Interest Expense on Finance Leases		0.8		0.9	0.7
Total Lease Rental Costs	[1]	$ 24.7		$ 22.7	22.2
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases		6 years 8 months 8 days		7 years 5 months 8 days
Weighted Average Remaining Lease Term, Finance Leases		5 years 6 months 14 days		5 years 10 months 24 days
Weighted Average Discount Rate, Operating Leases		3.56%		3.60%
Weighted Average Discount Rate, Finance Leases		4.19%		4.25%
Operating Cash Flows Used for Operating Leases		$ 19.0		$ 16.9
Operating Cash Flows Used for Finance Leases		0.8		0.9
Financing Cash Flows Used for Finance Leases		4.9		4.7	3.5
Non-cash Acquisitions Under Operating Leases		4.2		18.1
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Property, Plant and Equipment		992.9		899.6
Total Property, Plant and Equipment		10,421.3		9,802.1
Accumulated Amortization		2,458.3		2,350.0
Net Property, Plant and Equipment Under Finance Leases		19.3		21.6
Other Liabilities, Noncurrent		29.2		40.0
Finance Lease Liability Due Within One Year		118.1		139.6
Total Obligations Under Finance Leases		19.3		21.6
Operating Lease Asset and Related Obligations
Operating Lease Assets		81.2		92.0
Operating Lease Noncurrent Liability		68.6		79.5
Operating Lease Liability Due Within One Year		13.1		13.1
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		81.7		92.6
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		5.1
Year 2		4.4
Year 3		3.7
Year 4		2.5
Year 5		2.0
Finance Leases, Later Years		4.0
Finance Leases, Total Future Minimum Lease Payments		21.7
Imputed Interest on Finance Leases		2.4
Total Obligations Under Finance Leases		19.3		21.6
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		16.2
Year 2		15.2
Year 3		13.8
Year 4		12.1
Year 5		11.0
Operating Leases, Later Years		24.2
Operating Leases, Total Future Minimum Lease Payments		92.5
Imputed Interest on Operating Leases		10.8
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		81.7		92.6
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements		7.5
Ohio Power Co [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		0.0		0.0
Other Property, Plant and Equipment		32.1		31.4
Total Property, Plant and Equipment		32.1		31.4
Accumulated Amortization		12.8		9.8
Ohio Power Co [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent		14.9		16.9
Finance Lease Liability Due Within One Year		4.4		4.7
Ohio Power Co [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets		81.2		92.0
Public Service Co Of Oklahoma [Member]
Lease Rental Costs
Operating Lease, Cost		8.7		7.8	6.8
Finance Lease Right-of-Use Asset Amortization		3.2		3.5	3.1
Interest Expense on Finance Leases		0.6		0.7	0.6
Total Lease Rental Costs	[1]	$ 12.5		$ 12.0	10.5
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases		20 years 10 months 20 days		7 years 10 days
Weighted Average Remaining Lease Term, Finance Leases		6 years 2 months 4 days		6 years 1 month 28 days
Weighted Average Discount Rate, Operating Leases		3.35%		3.39%
Weighted Average Discount Rate, Finance Leases		4.23%		4.35%
Operating Cash Flows Used for Operating Leases		$ 8.7		$ 7.7
Operating Cash Flows Used for Finance Leases		0.6		0.7
Financing Cash Flows Used for Finance Leases		3.2		3.5	3.1
Non-cash Acquisitions Under Operating Leases		33.4		12.3
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		1,802.4		1,480.7
Other Property, Plant and Equipment		437.0		393.3
Total Property, Plant and Equipment		6,508.0		5,925.6
Accumulated Amortization		1,705.2		1,605.6
Net Property, Plant and Equipment Under Finance Leases		15.3		15.0
Other Liabilities, Noncurrent		19.4		20.6
Finance Lease Liability Due Within One Year		62.7		84.2
Total Obligations Under Finance Leases		15.3		15.0
Operating Lease Asset and Related Obligations
Operating Lease Assets		68.9		42.6
Operating Lease Noncurrent Liability		62.2		36.2
Operating Lease Liability Due Within One Year		6.9		6.5
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		69.1		42.7
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		3.6
Year 2		3.3
Year 3		2.8
Year 4		2.1
Year 5		1.8
Finance Leases, Later Years		3.9
Finance Leases, Total Future Minimum Lease Payments		17.5
Imputed Interest on Finance Leases		2.2
Total Obligations Under Finance Leases		15.3		15.0
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		9.2
Year 2		8.9
Year 3		8.1
Year 4		6.9
Year 5		6.0
Operating Leases, Later Years		62.6
Operating Leases, Total Future Minimum Lease Payments		101.7
Imputed Interest on Operating Leases		32.6
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		69.1		42.7
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements		4.6
Public Service Co Of Oklahoma [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		0.6		0.7
Other Property, Plant and Equipment		23.9		23.0
Total Property, Plant and Equipment		24.5		23.7
Accumulated Amortization		9.2		8.7
Public Service Co Of Oklahoma [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent		12.3		11.9
Finance Lease Liability Due Within One Year		3.0		3.1
Public Service Co Of Oklahoma [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets		68.9		42.6
Southwestern Electric Power Co [Member]
Lease Rental Costs
Operating Lease, Cost		12.1		9.4	8.0
Finance Lease Right-of-Use Asset Amortization		11.0		10.9	11.0
Interest Expense on Finance Leases		2.5		2.2	2.9
Total Lease Rental Costs	[1]	$ 25.6		$ 22.5	21.9
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases		20 years 2 months 26 days		7 years 6 months 14 days
Weighted Average Remaining Lease Term, Finance Leases		4 years 6 months 10 days		4 years 11 months 12 days
Weighted Average Discount Rate, Operating Leases		3.34%		3.45%
Weighted Average Discount Rate, Finance Leases		4.68%		4.77%
Operating Cash Flows Used for Operating Leases		$ 11.6		$ 9.4
Operating Cash Flows Used for Finance Leases		2.5		2.2
Financing Cash Flows Used for Finance Leases		10.9		10.9	$ 11.0
Non-cash Acquisitions Under Operating Leases		42.9		18.4
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		4,734.5		4,681.4
Other Property, Plant and Equipment		764.0		788.8
Total Property, Plant and Equipment		10,570.4		10,246.7
Accumulated Amortization		3,170.3		3,158.5
Net Property, Plant and Equipment Under Finance Leases		42.2		53.6
Other Liabilities, Noncurrent		63.0		95.2
Finance Lease Liability Due Within One Year		154.6		173.4
Total Obligations Under Finance Leases		49.7		55.3
Operating Lease Asset and Related Obligations
Operating Lease Noncurrent Liability		77.7		44.1
Operating Lease Liability Due Within One Year		8.1		7.9
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		85.8		52.0
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		12.6
Year 2		11.8
Year 3		15.9
Year 4		5.6
Year 5		2.3
Finance Leases, Later Years		6.0
Finance Leases, Total Future Minimum Lease Payments		54.2
Imputed Interest on Finance Leases		4.5
Total Obligations Under Finance Leases		49.7		55.3
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1		13.0
Year 2		11.8
Year 3		10.0
Year 4		8.7
Year 5		7.5
Operating Leases, Later Years		80.4
Operating Leases, Total Future Minimum Lease Payments		131.4
Imputed Interest on Operating Leases		45.6
Estimated Present Value of Future Minimum Lease Payments on Operating Leases		85.8		52.0
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements		5.2
Southwestern Electric Power Co [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation		34.3		37.7
Other Property, Plant and Equipment		55.7		52.4
Total Property, Plant and Equipment		90.0		90.1
Accumulated Amortization		47.8		36.5
Southwestern Electric Power Co [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent		38.9		44.6
Finance Lease Liability Due Within One Year		10.8		10.7
Southwestern Electric Power Co [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets		$ 80.1		$ 48.5

[1] Excludes variable and short-term lease costs, which were immaterial.

[2] Amount excludes $3 million of Net Property, Plant and Equipment Under Finance Leases classified as Assets Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[3] Amount excludes $3 million of Obligations Under Finance Leases 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 excludes $11 million of Obligations Under Operating Leases classified as Liabilities Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.

[5] (a) AEP’s future minimum lease payments include equal shares from AEGCo and I&M.

[6] Amount excludes $11 million of Operating Lease Assets classified as Assets Held for Sale on the balance sheet. See “Disposition of KPCo and KTCo” section of Note 7 for additional information.