Leases (Details) - USD ($) $ in Millions		1 Months Ended		12 Months Ended
		Feb. 26, 2024	Jan. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lease Rental Costs
Operating Lease, Cost				$ 149.9	$ 157.5	$ 275.3
Finance Lease Right-of-Use Asset Amortization				69.1	205.5	74.7
Interest Expense on Finance Leases				11.9	13.4	14.4
Total Lease Rental Costs	[1]			$ 230.9	$ 376.4	364.4
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases				12 years 6 months 29 days	12 years 8 months 8 days
Weighted Average Remaining Lease Term, Finance Leases				4 years 7 months 17 days	4 years 7 months 9 days
Weighted Average Discount Rate, Operating Leases				3.73%	3.54%
Weighted Average Discount Rate, Finance Leases				6.19%	5.76%
Operating Cash Flows Used for Operating Leases				$ 146.8	$ 155.1
Operating Cash Flows Used for Finance Leases				11.9	13.6
Financing Cash Flows Used for Finance Leases				68.3	309.5	64.0
Non-cash Acquisitions Under Operating Leases				99.8	191.4
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				24,329.5	25,834.2
Other Property, Plant and Equipment				6,484.9	5,971.8
Total Property, Plant and Equipment				101,246.4	97,021.4
Accumulated Amortization				24,553.0	23,682.3
Net Property, Plant and Equipment Under Finance Leases				204.5	212.7
Other Liabilities, Noncurrent				545.8	607.3
Finance Lease Liability Due Within One Year				1,251.1	1,278.2
Total Obligations Under Finance Leases				205.6	225.7
Operating Lease Asset and Related Obligations
Operating Lease Assets				620.2	645.5
Operating Lease Noncurrent Liability				519.4	552.5
Operating Lease Liability Due Within One Year				115.7	113.6
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				635.1	666.1
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				76.8
Year 2				48.6
Year 3				33.0
Year 4				26.2
Year 5				19.2
Finance Leases, Later Years				35.4
Finance Leases, Total Future Minimum Lease Payments				239.2
Imputed Interest on Finance Leases				33.6
Total Obligations Under Finance Leases				205.6	225.7
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				141.6
Year 2				103.3
Year 3				92.0
Year 4				82.6
Year 5				67.4
Operating Leases, Later Years				327.6
Operating Leases, Total Future Minimum Lease Payments				814.5
Imputed Interest on Operating Leases				179.4
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				635.1	666.1
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements				45.3
Leases (Textuals)
Repayments of Long-term Debt				2,196.1	2,345.4	2,989.3
Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				120.1	120.9
Other Property, Plant and Equipment				305.9	321.4
Total Property, Plant and Equipment				426.0	442.3
Accumulated Amortization				221.5	229.6
Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent				139.9	168.4
Finance Lease Liability Due Within One Year				65.7	57.3
Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets				620.2	645.5
AEP Texas Inc. [Member]
Lease Rental Costs
Operating Lease, Cost				34.0	18.4	18.4
Finance Lease Right-of-Use Asset Amortization				7.4	6.8	6.7
Interest Expense on Finance Leases				1.4	1.3	1.4
Total Lease Rental Costs	[1]			$ 42.8	$ 26.5	26.5
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases				3 years 11 months 26 days	4 years 3 months 29 days
Weighted Average Remaining Lease Term, Finance Leases				5 years 1 month 17 days	5 years 4 months 20 days
Weighted Average Discount Rate, Operating Leases				4.23%	4.15%
Weighted Average Discount Rate, Finance Leases				5.27%	4.75%
Operating Cash Flows Used for Operating Leases				$ 33.6	$ 18.3
Operating Cash Flows Used for Finance Leases				1.4	1.3
Financing Cash Flows Used for Finance Leases				7.4	6.8	6.7
Non-cash Acquisitions Under Operating Leases				12.4	36.7
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Property, Plant and Equipment				1,145.9	1,022.8
Total Property, Plant and Equipment				14,661.9	13,442.3
Accumulated Amortization				1,887.9	1,760.7
Net Property, Plant and Equipment Under Finance Leases				27.6	30.1
Other Liabilities, Noncurrent				111.3	93.2
Finance Lease Liability Due Within One Year				152.7	130.7
Total Obligations Under Finance Leases				27.6	30.1
Operating Lease Asset and Related Obligations
Operating Lease Noncurrent Liability				50.9	67.8
Operating Lease Liability Due Within One Year				28.7	28.6
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				79.6	96.4
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				8.3
Year 2				6.6
Year 3				5.1
Year 4				4.0
Year 5				2.8
Finance Leases, Later Years				5.1
Finance Leases, Total Future Minimum Lease Payments				31.9
Imputed Interest on Finance Leases				4.3
Total Obligations Under Finance Leases				27.6	30.1
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				32.1
Year 2				15.7
Year 3				13.3
Year 4				10.7
Year 5				7.8
Operating Leases, Later Years				8.1
Operating Leases, Total Future Minimum Lease Payments				87.7
Imputed Interest on Operating Leases				8.1
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				79.6	96.4
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements				10.9
Leases (Textuals)
Repayments of Long-term Debt				278.5	716.0	88.7
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				53.9	53.7
Total Property, Plant and Equipment				53.9	53.7
Accumulated Amortization				26.3	23.6
AEP Texas Inc. [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent				20.6	23.1
Finance Lease Liability Due Within One Year				7.0	7.0
AEP Texas Inc. [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets				77.6	94.7
AEP Transmission Co [Member]
Lease Rental Costs
Operating Lease, Cost				1.3	1.1	1.7
Finance Lease Right-of-Use Asset Amortization				0.0	0.0	0.0
Interest Expense on Finance Leases				0.0	0.0	0.0
Total Lease Rental Costs	[1]			$ 1.3	$ 1.1	1.7
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases				2 years 9 months 3 days	2 years 18 days
Weighted Average Remaining Lease Term, Finance Leases				0 years	0 years
Weighted Average Discount Rate, Operating Leases				3.61%	1.96%
Weighted Average Discount Rate, Finance Leases				0.00%	0.00%
Operating Cash Flows Used for Operating Leases				$ 1.3	$ 1.0
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				1.2	1.7
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Property, Plant and Equipment				501.4	476.8
Total Property, Plant and Equipment				15,789.0	14,366.9
Accumulated Amortization				1,291.3	1,027.0
Net Property, Plant and Equipment Under Finance Leases				0.0	0.0
Other Liabilities, Noncurrent				200.9	69.1
Finance Lease Liability Due Within One Year				24.7	8.3
Total Obligations Under Finance Leases				0.0	0.0
Operating Lease Asset and Related Obligations
Operating Lease Noncurrent Liability				1.4	1.5
Operating Lease Liability Due Within One Year				1.3	1.3
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				2.7	2.8
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				1.4
Year 2				0.7
Year 3				0.4
Year 4				0.2
Year 5				0.1
Operating Leases, Later Years				0.0
Operating Leases, Total Future Minimum Lease Payments				2.8
Imputed Interest on Operating Leases				0.1
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				2.7	2.8
Leases (Textuals)
Repayments of Long-term Debt				60.0	104.0	50.0
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				2.6	2.7
Appalachian Power Co [Member]
Lease Rental Costs
Operating Lease, Cost				18.5	17.9	19.3
Finance Lease Right-of-Use Asset Amortization				8.3	7.9	7.7
Interest Expense on Finance Leases				1.8	2.0	2.4
Total Lease Rental Costs	[1]			$ 28.6	$ 27.8	29.4
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases				6 years 3 days	5 years 3 months 14 days
Weighted Average Remaining Lease Term, Finance Leases				4 years 1 month 28 days	4 years 3 months
Weighted Average Discount Rate, Operating Leases				3.50%	3.61%
Weighted Average Discount Rate, Finance Leases				7.04%	7.09%
Operating Cash Flows Used for Operating Leases				$ 18.3	$ 17.9
Operating Cash Flows Used for Finance Leases				1.8	2.0
Financing Cash Flows Used for Finance Leases				8.3	7.9	7.7
Non-cash Acquisitions Under Operating Leases				15.7	23.1
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				7,041.3	6,776.8
Other Property, Plant and Equipment				981.3	883.3
Total Property, Plant and Equipment				18,620.2	17,781.2
Accumulated Amortization				5,688.7	5,402.0
Net Property, Plant and Equipment Under Finance Leases				26.0	29.3
Other Liabilities, Noncurrent				70.9	49.6
Finance Lease Liability Due Within One Year				193.6	171.2
Total Obligations Under Finance Leases				26.0	29.3
Operating Lease Asset and Related Obligations
Operating Lease Assets				73.7	73.6
Operating Lease Noncurrent Liability				59.8	59.1
Operating Lease Liability Due Within One Year				14.6	15.0
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				74.4	74.1
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				9.9
Year 2				8.5
Year 3				3.5
Year 4				2.3
Year 5				1.9
Finance Leases, Later Years				3.4
Finance Leases, Total Future Minimum Lease Payments				29.5
Imputed Interest on Finance Leases				3.5
Total Obligations Under Finance Leases				26.0	29.3
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				17.8
Year 2				14.8
Year 3				13.3
Year 4				12.1
Year 5				10.0
Operating Leases, Later Years				16.8
Operating Leases, Total Future Minimum Lease Payments				84.8
Imputed Interest on Operating Leases				10.4
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				74.4	74.1
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements				5.8
Leases (Textuals)
Repayments of Long-term Debt				26.6	230.4	393.0
Appalachian Power Co [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				41.0	41.1
Other Property, Plant and Equipment				22.1	20.1
Total Property, Plant and Equipment				63.1	61.2
Accumulated Amortization				37.1	31.9
Appalachian Power Co [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent				17.8	21.6
Finance Lease Liability Due Within One Year				8.2	7.7
Appalachian Power Co [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets				73.7	73.6
Indiana Michigan Power Co [Member]
Lease Rental Costs
Operating Lease, Cost				19.6	29.5	90.2
Finance Lease Right-of-Use Asset Amortization				7.3	78.7	12.9
Interest Expense on Finance Leases				2.5	3.1	3.0
Total Lease Rental Costs	[1]			$ 29.4	$ 111.3	106.1
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases				4 years 6 months 10 days	5 years 9 months 14 days
Weighted Average Remaining Lease Term, Finance Leases				4 years 11 months 12 days	4 years 9 months 3 days
Weighted Average Discount Rate, Operating Leases				3.89%	3.62%
Weighted Average Discount Rate, Finance Leases				8.62%	8.99%
Operating Cash Flows Used for Operating Leases				$ 19.5	$ 29.7
Operating Cash Flows Used for Finance Leases				2.5	3.2
Financing Cash Flows Used for Finance Leases				7.4	130.7	6.8
Non-cash Acquisitions Under Operating Leases				7.9	19.1
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				5,646.8	5,585.1
Other Property, Plant and Equipment				898.5	839.3
Total Property, Plant and Equipment				12,007.4	11,544.3
Accumulated Amortization				4,378.4	4,132.8
Net Property, Plant and Equipment Under Finance Leases				31.5	33.8
Other Liabilities, Noncurrent				57.7	58.8
Finance Lease Liability Due Within One Year				91.9	105.8
Total Obligations Under Finance Leases				31.5	34.0
Operating Lease Asset and Related Obligations
Operating Lease Assets				53.8	64.3
Operating Lease Noncurrent Liability				37.7	48.9
Operating Lease Liability Due Within One Year				16.8	16.0
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				54.5	64.9
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				12.8
Year 2				7.2
Year 3				4.5
Year 4				4.0
Year 5				3.3
Finance Leases, Later Years				7.3
Finance Leases, Total Future Minimum Lease Payments				39.1
Imputed Interest on Finance Leases				7.6
Total Obligations Under Finance Leases				31.5	34.0
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				18.9
Year 2				10.6
Year 3				9.7
Year 4				8.9
Year 5				7.0
Operating Leases, Later Years				4.8
Operating Leases, Total Future Minimum Lease Payments				59.9
Imputed Interest on Operating Leases				5.4
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				54.5	64.9
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements				4.1
Leases (Textuals)
Repayments of Long-term Debt				343.3	83.4	383.5
Indiana Michigan Power Co [Member] | Notes Payable, Other Payables [Member] | Subsequent Event [Member]
Leases (Textuals)
Repayments of Long-term Debt		$ 8.0	$ 8.0
Indiana Michigan Power Co [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				28.2	28.0
Other Property, Plant and Equipment				42.3	40.6
Total Property, Plant and Equipment				70.5	68.6
Accumulated Amortization				39.0	34.8
Indiana Michigan Power Co [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent				20.8	27.1
Finance Lease Liability Due Within One Year				10.7	6.9
Indiana Michigan Power Co [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets				53.8	64.3
Ohio Power Co [Member]
Lease Rental Costs
Operating Lease, Cost				17.3	16.9	19.0
Finance Lease Right-of-Use Asset Amortization				5.0	4.9	4.9
Interest Expense on Finance Leases				0.9	0.8	0.8
Total Lease Rental Costs	[1]			$ 23.2	$ 22.6	24.7
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases				5 years 4 months 9 days	5 years 11 months 23 days
Weighted Average Remaining Lease Term, Finance Leases				4 years 11 months 19 days	5 years 3 months 7 days
Weighted Average Discount Rate, Operating Leases				3.93%	3.73%
Weighted Average Discount Rate, Finance Leases				5.32%	4.53%
Operating Cash Flows Used for Operating Leases				$ 17.0	$ 17.5
Operating Cash Flows Used for Finance Leases				0.9	0.8
Financing Cash Flows Used for Finance Leases				5.0	4.9	4.9
Non-cash Acquisitions Under Operating Leases				10.2	8.4
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Property, Plant and Equipment				1,125.0	1,051.4
Total Property, Plant and Equipment				12,013.5	11,174.6
Accumulated Amortization				2,713.6	2,565.3
Net Property, Plant and Equipment Under Finance Leases				18.2	18.9
Other Liabilities, Noncurrent				34.4	66.0
Finance Lease Liability Due Within One Year				183.3	154.2
Total Obligations Under Finance Leases				18.2	18.9
Operating Lease Asset and Related Obligations
Operating Lease Assets				69.9	73.8
Operating Lease Noncurrent Liability				56.7	60.3
Operating Lease Liability Due Within One Year				13.5	13.5
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				70.2	73.8
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				5.8
Year 2				4.3
Year 3				3.1
Year 4				2.5
Year 5				2.0
Finance Leases, Later Years				3.2
Finance Leases, Total Future Minimum Lease Payments				20.9
Imputed Interest on Finance Leases				2.7
Total Obligations Under Finance Leases				18.2	18.9
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				16.9
Year 2				15.3
Year 3				14.1
Year 4				12.8
Year 5				10.6
Operating Leases, Later Years				9.1
Operating Leases, Total Future Minimum Lease Payments				78.8
Imputed Interest on Operating Leases				8.6
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				70.2	73.8
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements				7.2
Leases (Textuals)
Repayments of Long-term Debt				0.6	0.1	500.1
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				33.7	32.7
Total Property, Plant and Equipment				33.7	32.7
Accumulated Amortization				15.5	13.8
Ohio Power Co [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent				13.2	14.2
Finance Lease Liability Due Within One Year				5.0	4.7
Ohio Power Co [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets				69.9	73.8
Public Service Co Of Oklahoma [Member]
Lease Rental Costs
Operating Lease, Cost				13.5	11.8	8.7
Finance Lease Right-of-Use Asset Amortization				3.3	3.2	3.2
Interest Expense on Finance Leases				0.7	0.6	0.6
Total Lease Rental Costs	[1]			$ 17.5	$ 15.6	12.5
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases				23 years 10 months 6 days	23 years 10 months 24 days
Weighted Average Remaining Lease Term, Finance Leases				5 years 9 months 3 days	6 years 7 days
Weighted Average Discount Rate, Operating Leases				3.72%	3.43%
Weighted Average Discount Rate, Finance Leases				5.14%	4.63%
Operating Cash Flows Used for Operating Leases				$ 12.5	$ 10.5
Operating Cash Flows Used for Finance Leases				0.7	0.6
Financing Cash Flows Used for Finance Leases				3.3	3.2	3.2
Non-cash Acquisitions Under Operating Leases				15.5	46.0
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				2,695.5	2,394.8
Other Property, Plant and Equipment				505.9	469.3
Total Property, Plant and Equipment				8,194.2	7,464.2
Accumulated Amortization				2,081.9	1,837.7
Net Property, Plant and Equipment Under Finance Leases				13.8	15.0
Other Liabilities, Noncurrent				33.8	21.3
Finance Lease Liability Due Within One Year				106.2	82.0
Total Obligations Under Finance Leases				13.8	15.0
Operating Lease Asset and Related Obligations
Operating Lease Assets				112.8	106.1
Operating Lease Noncurrent Liability				106.8	99.3
Operating Lease Liability Due Within One Year				10.1	8.9
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				116.9	108.2
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				3.7
Year 2				2.9
Year 3				2.5
Year 4				2.0
Year 5				1.7
Finance Leases, Later Years				3.3
Finance Leases, Total Future Minimum Lease Payments				16.1
Imputed Interest on Finance Leases				2.3
Total Obligations Under Finance Leases				13.8	15.0
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				12.2
Year 2				11.1
Year 3				10.3
Year 4				9.3
Year 5				7.9
Operating Leases, Later Years				129.1
Operating Leases, Total Future Minimum Lease Payments				179.9
Imputed Interest on Operating Leases				63.0
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				116.9	108.2
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements				4.7
Leases (Textuals)
Repayments of Long-term Debt				0.5	500.5	750.5
Public Service Co Of Oklahoma [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				0.6	0.6
Other Property, Plant and Equipment				25.5	25.2
Total Property, Plant and Equipment				26.1	25.8
Accumulated Amortization				12.3	10.8
Public Service Co Of Oklahoma [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent				10.7	11.7
Finance Lease Liability Due Within One Year				3.1	3.3
Public Service Co Of Oklahoma [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets				112.8	106.1
Southwestern Electric Power Co [Member]
Lease Rental Costs
Operating Lease, Cost				17.5	15.3	12.1
Finance Lease Right-of-Use Asset Amortization				19.9	10.8	11.0
Interest Expense on Finance Leases				1.4	2.1	2.5
Total Lease Rental Costs	[1]			$ 38.8	$ 28.2	25.6
Supplemental Information Related to Leases
Weighted-Average Remaining Lease Term, Operating Leases				22 years 6 months	23 years 6 months 18 days
Weighted Average Remaining Lease Term, Finance Leases				4 years 9 months 10 days	4 years 1 month 17 days
Weighted Average Discount Rate, Operating Leases				3.53%	3.41%
Weighted Average Discount Rate, Finance Leases				5.22%	4.80%
Operating Cash Flows Used for Operating Leases				$ 16.5	$ 13.7
Operating Cash Flows Used for Finance Leases				1.4	2.1
Financing Cash Flows Used for Finance Leases				19.1	10.8	10.9
Non-cash Acquisitions Under Operating Leases				14.3	53.6
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				4,790.7	5,476.2
Other Property, Plant and Equipment				814.4	804.4
Total Property, Plant and Equipment				11,645.6	11,789.5
Accumulated Amortization				3,087.2	3,527.3
Net Property, Plant and Equipment Under Finance Leases				29.0	29.6
Other Liabilities, Noncurrent				93.8	68.4
Finance Lease Liability Due Within One Year				154.6	172.0
Total Obligations Under Finance Leases				30.1	42.2
Operating Lease Asset and Related Obligations
Operating Lease Noncurrent Liability				122.5	120.2
Operating Lease Liability Due Within One Year				9.0	8.4
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				131.5	128.6
Finance Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				12.6
Year 2				4.6
Year 3				3.9
Year 4				3.5
Year 5				3.0
Finance Leases, Later Years				7.2
Finance Leases, Total Future Minimum Lease Payments				34.8
Imputed Interest on Finance Leases				4.7
Total Obligations Under Finance Leases				30.1	42.2
Operating Lease Liabilities Rolling Future Minimum Lease Payments
Year 1				16.2
Year 2				15.0
Year 3				12.9
Year 4				11.5
Year 5				9.5
Operating Leases, Later Years				135.6
Operating Leases, Total Future Minimum Lease Payments				200.7
Imputed Interest on Operating Leases				69.2
Estimated Present Value of Future Minimum Lease Payments on Operating Leases				131.5	128.6
Maximum Potential Loss
Max Potential Loss on Master Lease Agreements				5.4
Leases (Textuals)
Repayments of Long-term Debt				94.1	6.2	$ 381.2
Southwestern Electric Power Co [Member] | Finance Lease Assets [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Generation				25.3	25.9
Other Property, Plant and Equipment				32.0	58.3
Total Property, Plant and Equipment				57.3	84.2
Accumulated Amortization				28.3	54.6
Southwestern Electric Power Co [Member] | Finance Lease Liabilities [Member]
Property, Plant and Equipment and Other Related Obligations Under Finance Leases
Other Liabilities, Noncurrent				18.8	31.3
Finance Lease Liability Due Within One Year				11.3	10.9
Southwestern Electric Power Co [Member] | Operating Lease Assets [Member]
Operating Lease Asset and Related Obligations
Operating Lease Assets				$ 126.3	$ 123.4

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