Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Generation And Marketing [Member]	Appalachian Power Co [Member]	AEP Texas Inc. [Member]	AEP Transmission Co [Member]	Indiana Michigan Power Co [Member]	Ohio Power Co [Member]	Public Service Co Of Oklahoma [Member]	Southwestern Electric Power Co [Member]	Common Stock [Member]	Common Stock [Member] Appalachian Power Co [Member]	Common Stock [Member] Indiana Michigan Power Co [Member]	Common Stock [Member] Ohio Power Co [Member]	Common Stock [Member] Public Service Co Of Oklahoma [Member]	Common Stock [Member] Southwestern Electric Power Co [Member]	Additional Paid-in Capital [Member]		Additional Paid-in Capital [Member] Appalachian Power Co [Member]	Additional Paid-in Capital [Member] AEP Texas Inc. [Member]	Additional Paid-in Capital [Member] AEP Transmission Co [Member]	Additional Paid-in Capital [Member] Indiana Michigan Power Co [Member]	Additional Paid-in Capital [Member] Ohio Power Co [Member]	Additional Paid-in Capital [Member] Public Service Co Of Oklahoma [Member]	Additional Paid-in Capital [Member] Southwestern Electric Power Co [Member]	Retained Earnings [Member]		Retained Earnings [Member] Appalachian Power Co [Member]	Retained Earnings [Member] AEP Texas Inc. [Member]	Retained Earnings [Member] AEP Transmission Co [Member]	Retained Earnings [Member] Indiana Michigan Power Co [Member]	Retained Earnings [Member] Ohio Power Co [Member]	Retained Earnings [Member] Public Service Co Of Oklahoma [Member]	Retained Earnings [Member] Southwestern Electric Power Co [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Other Comprehensive Income [Member] Appalachian Power Co [Member]	Accumulated Other Comprehensive Income [Member] AEP Texas Inc. [Member]	Accumulated Other Comprehensive Income [Member] Indiana Michigan Power Co [Member]	Accumulated Other Comprehensive Income [Member] Public Service Co Of Oklahoma [Member]	Accumulated Other Comprehensive Income [Member] Southwestern Electric Power Co [Member]	Noncontrolling Interests [Member]	Noncontrolling Interests [Member] Southwestern Electric Power Co [Member]	Dry Lake Solar Project	Dry Lake Solar Project Noncontrolling Interests [Member]	Dry Lake Solar Project Noncontrolling Interests [Member] Generation And Marketing [Member]
Beginning Balance at Dec. 31, 2019					$ 4,009.5															$ 2,480.6									$ 1,528.9
Beginning Balance at Dec. 31, 2019	$ 19,913.2		$ 4,172.4	$ 2,961.1		$ 2,544.4	$ 2,508.5	$ 1,373.3	$ 2,441.1	$ 3,343.4	$ 260.4	$ 56.6	$ 321.2	$ 157.2	$ 135.7	$ 6,535.6		$ 1,828.7	$ 1,457.9		$ 980.9	$ 838.8	$ 364.0	$ 676.6	$ 9,900.9		$ 2,078.3	$ 1,516.0		$ 1,518.5	$ 1,348.5	$ 851.0	$ 1,629.5	$ (147.7)	$ 5.0	$ (12.8)	$ (11.6)	$ 1.1	$ (1.3)	$ 281.0	$ 0.6
Beginning Balance, Shares at Dec. 31, 2019										514,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock, Value	56.1									$ 6.8						49.3
Issuance of Common Stock, Shares										1,000,000.0
Common Stock Dividends	(363.7)																								(359.1)	[1]
Common Stock Dividends			(50.0)			(21.3)	(21.9)																				(50.0)			(21.3)	(21.9)
Common Stock Dividends									(0.7)																															(4.6)	(0.7)
Other Changes in Equity	(30.2)															(29.0)																								(1.2)
Stockholders Equity ASU 2016-13 Adoption	1.8					0.4	0.3	0.3	1.6																1.8					0.4	0.3	0.3	1.6
Capital Contribution from Member					185.0															185.0
Net Income (Loss)																									495.2								15.1
Net Income (Loss) Attributable to Noncontrolling Interests																																								4.1	1.0
Net Income (Loss)	499.3		115.3	47.6	117.8	92.3	75.1	(10.3)	16.1																		115.3	47.6	117.8	92.3	75.1	(10.3)
Other Comprehensive Income (Loss)	(68.8)		(5.1)	0.3		0.4		(0.2)																										(68.8)	(5.1)	0.3	0.4	(0.2)
Ending Balance at Mar. 31, 2020					4,312.3															2,665.6									1,646.7
Ending Balance at Mar. 31, 2020	$ 20,007.7		4,232.6	3,009.0		2,616.2	2,562.0	1,363.1	2,458.1	$ 3,350.2	260.4	56.6	321.2	157.2	135.7	6,555.9		1,828.7	1,457.9		980.9	838.8	364.0	676.6	10,038.8		2,143.6	1,563.6		1,589.9	1,402.0	841.0	1,646.2	(216.5)	(0.1)	(12.5)	(11.2)	0.9	(1.3)	279.3	0.9
Ending Balance, Shares at Mar. 31, 2020										515,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared	$ 0.70
Beginning Balance at Dec. 31, 2019					4,009.5															2,480.6									1,528.9
Beginning Balance at Dec. 31, 2019	$ 19,913.2		4,172.4	2,961.1		2,544.4	2,508.5	1,373.3	2,441.1	$ 3,343.4	260.4	56.6	321.2	157.2	135.7	6,535.6		1,828.7	1,457.9		980.9	838.8	364.0	676.6	9,900.9		2,078.3	1,516.0		1,518.5	1,348.5	851.0	1,629.5	(147.7)	5.0	(12.8)	(11.6)	1.1	(1.3)	281.0	0.6
Beginning Balance, Shares at Dec. 31, 2019										514,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other Changes in Equity																									(120.6)
Dividends Paid on Common Stock			(150.0)		(5.0)	(63.7)	(65.6)	0.0
Net Income (Loss)	1,764.6								161.8
Net Income (Loss) Attributable to Noncontrolling Interests	(2.6)								2.1
Net Income (Loss)	1,762.0	$ 203.6	313.2	197.1	309.1	232.8	215.0	116.4	163.9
Other Comprehensive Income (Loss)	12.3		(7.2)	0.9		1.1			0.0
Ending Balance at Sep. 30, 2020					4,498.6															2,665.6									1,833.0
Ending Balance at Sep. 30, 2020	20,634.6		4,328.4	3,159.1		2,715.0	2,658.2	1,489.2	2,604.3	$ 3,357.6	260.4	56.6	321.2	157.2	0.1	6,522.3		1,828.7	1,457.9		980.9	838.8	364.0	812.2	10,621.4		2,241.5	1,713.1		1,688.0	1,498.2	967.7	1,792.9	(135.4)	(2.2)	(11.9)	(10.5)	0.3	(1.3)	268.7	0.4
Ending Balance, Shares at Sep. 30, 2020										516,600,000
Beginning Balance at Mar. 31, 2020					4,312.3															2,665.6									1,646.7
Beginning Balance at Mar. 31, 2020	20,007.7		4,232.6	3,009.0		2,616.2	2,562.0	1,363.1	2,458.1	$ 3,350.2	260.4	56.6	321.2	157.2	135.7	6,555.9		1,828.7	1,457.9		980.9	838.8	364.0	676.6	10,038.8		2,143.6	1,563.6		1,589.9	1,402.0	841.0	1,646.2	(216.5)	(0.1)	(12.5)	(11.2)	0.9	(1.3)	279.3	0.9
Beginning Balance, Shares at Mar. 31, 2020										515,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock, Value	54.9									$ 5.2						49.7
Issuance of Common Stock, Shares										800,000
Common Stock Dividends	(340.9)																								(337.7)	[1]
Common Stock Dividends			(50.0)			(21.2)	(21.9)																				(50.0)			(21.2)	(21.9)
Common Stock Dividends									(1.2)																															(3.2)	(1.2)
Other Changes in Equity	(1.6)															(2.6)																								1.0
Dividends Paid on Common Stock					(5.0)																								(5.0)
Net Income (Loss)																									520.8								58.8
Net Income (Loss) Attributable to Noncontrolling Interests																																								(6.3)	0.4
Net Income (Loss)	514.5		81.3	66.9	73.7	63.8	80.9	46.4	59.2																		81.3	66.9	73.7	63.8	80.9	46.4
Other Comprehensive Income (Loss)	43.6		(1.8)	0.3		0.4		(0.3)																										43.6	(1.8)	0.3	0.4	(0.3)
Ending Balance at Jun. 30, 2020					4,381.0															2,665.6									1,715.4
Ending Balance at Jun. 30, 2020	$ 20,278.2		4,262.1	3,076.2		2,659.2	2,621.0	1,409.2	2,516.1	$ 3,355.4	260.4	56.6	321.2	157.2	135.7	6,603.0		1,828.7	1,457.9		980.9	838.8	364.0	676.6	10,221.9		2,174.9	1,630.5		1,632.5	1,461.0	887.4	1,705.0	(172.9)	(1.9)	(12.2)	(10.8)	0.6	(1.3)	270.8	0.1
Ending Balance, Shares at Jun. 30, 2020										516,200,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared	$ 0.70
Issuance of Common Stock, Value	$ 25.5									$ 2.2						23.3
Issuance of Common Stock, Shares										400,000
Common Stock Dividends	(351.1)																								(349.1)	[1]
Common Stock Dividends			(50.0)			(21.2)	(21.8)																				(50.0)			(21.2)	(21.8)
Common Stock Dividends									(0.4)																															(2.0)	(0.4)
Other Changes in Equity	(103.7)															(104.0)	[2]																							0.3
Net Income (Loss)	748.6								87.9																748.6								87.9
Net Income (Loss) Attributable to Noncontrolling Interests	(0.4)								0.7																															(0.4)	0.7
Net Income (Loss)	748.2	114.6	116.6	82.6	117.6	76.7	59.0	80.3	88.6																		116.6	82.6	117.6	76.7	59.0	80.3
Other Comprehensive Income (Loss)	37.5		(0.3)	0.3		0.3		(0.3)	0.0																									37.5	(0.3)	0.3	0.3	(0.3)
Reverse Common Stock Split									0.0						(135.6)									135.6
Ending Balance at Sep. 30, 2020					4,498.6															2,665.6									1,833.0
Ending Balance at Sep. 30, 2020	$ 20,634.6		4,328.4	3,159.1		2,715.0	2,658.2	1,489.2	2,604.3	$ 3,357.6	260.4	56.6	321.2	157.2	0.1	6,522.3		1,828.7	1,457.9		980.9	838.8	364.0	812.2	10,621.4		2,241.5	1,713.1		1,688.0	1,498.2	967.7	1,792.9	(135.4)	(2.2)	(11.9)	(10.5)	0.3	(1.3)	268.7	0.4
Ending Balance, Shares at Sep. 30, 2020										516,600,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared	$ 0.70
Beginning Balance at Dec. 31, 2020					4,712.9															2,765.6									1,947.3
Beginning Balance at Dec. 31, 2020	$ 20,774.5		4,344.3	3,206.0		2,749.2	2,692.7	$ 1,545.6	2,627.7	$ 3,359.3	260.4	56.6	321.2	157.2	0.1	6,588.9		1,828.7	1,457.9		980.9	838.8	414.0	812.2	10,687.8		2,248.0	1,757.0		1,718.7	1,532.7	974.3	1,811.9	(85.1)	7.2	(8.9)	(7.0)	0.1	1.9	223.6	1.6
Beginning Balance, Shares at Dec. 31, 2020	516,808,354							10,482,000		516,800,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock, Value	$ 184.6									$ 17.1						167.5
Issuance of Common Stock, Shares										2,700,000
Common Stock Dividends	(372.0)																								(369.5)	[3]
Common Stock Dividends			(12.5)			(25.0)	(21.9)																				(12.5)			(25.0)	(21.9)
Common Stock Dividends									(1.0)																															(2.5)	(1.0)
Other Changes in Equity	(19.1)															(21.9)									(0.6)															3.4
Capital Contribution from Member					124.0			$ 425.0	100.0											124.0			425.0	100.0
Acquisition																																										$ 18.9	$ 18.9
Net Income (Loss)																									575.0								62.4
Net Income (Loss) Attributable to Noncontrolling Interests																																								3.8	1.0
Net Income (Loss)	578.8		122.5	46.1	151.7	70.8	68.2	(2.7)	63.4																		122.5	46.1	151.7	70.8	68.2	(2.7)
Other Comprehensive Income (Loss)	54.3		7.9	0.3		0.5		(0.1)																										54.3	7.9	0.3	0.5	(0.1)
Ending Balance at Mar. 31, 2021					4,988.6															2,889.6									2,099.0
Ending Balance at Mar. 31, 2021	$ 21,220.0		4,462.2	3,252.4		2,795.5	2,739.0	1,967.8	2,790.1	$ 3,376.4	260.4	56.6	321.2	157.2	0.1	6,734.5		1,828.7	1,457.9		980.9	838.8	839.0	912.2	10,892.7		2,358.0	1,803.1		1,764.5	1,579.0	971.6	1,874.3	(30.8)	15.1	(8.6)	(6.5)	0.0	1.9	247.2	1.6
Ending Balance, Shares at Mar. 31, 2021										519,500,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared	$ 0.74
Beginning Balance at Dec. 31, 2020					4,712.9															2,765.6									1,947.3
Beginning Balance at Dec. 31, 2020	$ 20,774.5		4,344.3	3,206.0		2,749.2	2,692.7	$ 1,545.6	2,627.7	$ 3,359.3	260.4	56.6	321.2	157.2	0.1	6,588.9		1,828.7	1,457.9		980.9	838.8	414.0	812.2	10,687.8		2,248.0	1,757.0		1,718.7	1,532.7	974.3	1,811.9	(85.1)	7.2	(8.9)	(7.0)	0.1	1.9	223.6	1.6
Beginning Balance, Shares at Dec. 31, 2020	516,808,354							10,482,000		516,800,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other Changes in Equity																									0.0
Acquisition																																												$ 16.0
Dividends Paid on Common Stock			(37.5)		(112.5)	(175.0)	(71.9)	$ (20.0)
Net Income (Loss)	$ 1,949.2								208.1
Net Income (Loss) Attributable to Noncontrolling Interests	0.3								2.6
Net Income (Loss)	1,949.5	184.2	275.1	225.4	445.7	232.1	198.6	136.6	210.7
Other Comprehensive Income (Loss)	359.8		5.4	0.9		1.2			(0.1)
Ending Balance at Sep. 30, 2021					5,230.1															2,949.6									2,280.5
Ending Balance at Sep. 30, 2021	$ 22,527.2		4,587.3	3,432.3		2,807.5	2,819.4	$ 2,287.1	3,114.5	$ 3,404.5	260.4	56.6	321.2	157.2	0.1	7,075.9		1,828.7	1,457.9		980.9	838.8	1,039.0	1,092.2	11,523.0		2,485.6	1,982.4		1,775.8	1,659.4	1,090.9	2,020.0	274.7	12.6	(8.0)	(5.8)	0.0	1.8	249.1	0.4
Ending Balance, Shares at Sep. 30, 2021	523,773,631							10,482,000		523,800,000
Beginning Balance at Mar. 31, 2021					4,988.6															2,889.6									2,099.0
Beginning Balance at Mar. 31, 2021	$ 21,220.0		4,462.2	3,252.4		2,795.5	2,739.0	$ 1,967.8	2,790.1	$ 3,376.4	260.4	56.6	321.2	157.2	0.1	6,734.5		1,828.7	1,457.9		980.9	838.8	839.0	912.2	10,892.7		2,358.0	1,803.1		1,764.5	1,579.0	971.6	1,874.3	(30.8)	15.1	(8.6)	(6.5)	0.0	1.9	247.2	1.6
Beginning Balance, Shares at Mar. 31, 2021										519,500,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock, Value	72.3									$ 6.3						66.0
Issuance of Common Stock, Shares										900,000
Common Stock Dividends	(374.5)																								(371.8)	[3]
Common Stock Dividends			(12.5)			(75.0)	(21.9)	(10.0)																			(12.5)			(75.0)	(21.9)	(10.0)
Common Stock Dividends									(0.6)																															(2.7)	(0.6)
Other Changes in Equity	10.5															(0.2)									(0.4)															11.1
Capital Contribution from Member					60.0			200.0	75.0											60.0			200.0	75.0
Net Income (Loss)																									578.2								36.8
Net Income (Loss) Attributable to Noncontrolling Interests																																								(4.4)	0.6
Net Income (Loss)	573.8		66.3	79.8	148.6	57.2	74.0	46.1	37.4																		66.3	79.8	148.6	57.2	74.0	46.1
Other Comprehensive Income (Loss)	127.8		(1.2)	0.3		0.3																												127.8	(1.2)	0.3	0.3
Ending Balance at Jun. 30, 2021					5,197.2															2,949.6									2,247.6
Ending Balance at Jun. 30, 2021	$ 21,629.9		4,514.8	3,332.5		2,778.0	2,791.1	2,203.9	2,901.9	$ 3,382.7	260.4	56.6	321.2	157.2	0.1	6,800.3		1,828.7	1,457.9		980.9	838.8	1,039.0	987.2	11,098.7		2,411.8	1,882.9		1,746.7	1,631.1	1,007.7	1,911.1	97.0	13.9	(8.3)	(6.2)	0.0	1.9	251.2	1.6
Ending Balance, Shares at Jun. 30, 2021										520,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared	$ 0.74
Issuance of Common Stock, Value	$ 291.1									$ 21.8						269.3
Issuance of Common Stock, Shares										3,400,000
Common Stock Dividends	(376.2)																								(371.7)	[3]
Common Stock Dividends			(12.5)			(75.0)	(28.1)	(10.0)																			(12.5)			(75.0)	(28.1)	(10.0)
Common Stock Dividends									(2.2)																															(4.5)	(2.2)
Other Changes in Equity	7.8															6.3																								1.5
Capital Contribution from Member									105.0															105.0
Dividends Paid on Common Stock					(112.5)																								(112.5)
Net Income (Loss)	796.0								108.9																796.0								108.9
Net Income (Loss) Attributable to Noncontrolling Interests	0.9								1.0																															0.9	1.0
Net Income (Loss)	796.9	$ 99.5	86.3	99.5	145.4	104.1	56.4	93.2	109.9																		86.3	99.5	145.4	104.1	56.4	93.2
Other Comprehensive Income (Loss)	177.7		(1.3)	0.3		0.4			(0.1)																									177.7	(1.3)	0.3	0.4		(0.1)
Ending Balance at Sep. 30, 2021					$ 5,230.1															$ 2,949.6									$ 2,280.5
Ending Balance at Sep. 30, 2021	$ 22,527.2		$ 4,587.3	$ 3,432.3		$ 2,807.5	$ 2,819.4	$ 2,287.1	$ 3,114.5	$ 3,404.5	$ 260.4	$ 56.6	$ 321.2	$ 157.2	$ 0.1	$ 7,075.9		$ 1,828.7	$ 1,457.9		$ 980.9	$ 838.8	$ 1,039.0	$ 1,092.2	$ 11,523.0		$ 2,485.6	$ 1,982.4		$ 1,775.8	$ 1,659.4	$ 1,090.9	$ 2,020.0	$ 274.7	$ 12.6	$ (8.0)	$ (5.8)	$ 0.0	$ 1.8	$ 249.1	$ 0.4
Ending Balance, Shares at Sep. 30, 2021	523,773,631							10,482,000		523,800,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared	$ 0.74

[1] Cash dividends declared per AEP common share were $0.70.

[2] Includes $(121) million related to a forward equity purchase contract associated with the issuance of Equity Units.

[3] Cash dividends declared per AEP common share were $0.74.