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] Ohio 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]	AEP Wind Holdings LLC [Member]	AEP Wind Holdings LLC [Member] Noncontrolling Interests [Member]	Santa Rita East [Member]	Santa Rita East [Member] Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2018						$ 3,569.8															$ 2,480.6									$ 1,089.2
Beginning Balance at Dec. 31, 2018		$ 19,059.4		$ 4,006.1	$ 2,580.5		$ 2,352.8	$ 2,297.4	$ 1,248.0	$ 2,315.6	$ 3,337.4	$ 260.4	$ 56.6	$ 321.2	$ 157.2	$ 135.7	$ 6,486.1		$ 1,828.7	$ 1,257.9		$ 980.9	$ 838.8	$ 364.0	$ 676.6	$ 9,325.3		$ 1,922.0	$ 1,337.7		$ 1,329.1	$ 1,136.4	$ 724.7	$ 1,508.4	$ (120.4)	$ (5.0)	$ (15.1)	$ (13.8)	$ 1.0	$ 2.1	$ (5.4)	$ 31.0	$ 0.3
Beginning Balance, Shares at Dec. 31, 2018											513,500,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock, Value		14.5									$ 1.2						13.3
Issuance of Common Stock, Shares											100,000
Common Stock Dividends		(333.6)																								(332.5)	[1]
Common Stock Dividends				(50.0)			(20.0)	(25.0)	(11.3)	(18.7)																		(50.0)			(20.0)	(25.0)	(11.3)	(18.7)
Common Stock Dividends										(1.1)																																(1.1)	(1.1)
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30		(55.6)															(56.6)	[2]																								1.0
Capital Contribution from Member					200.0															200.0
Net Income (Loss)																										572.8								27.8
Net Income (Loss) Attributable to Noncontrolling Interests																																										1.3	1.2
Net Income (Loss)		574.1		133.7	34.4	104.3	98.9	128.0	6.2	29.0																		133.7	34.4	104.3	98.9	128.0	6.2
Other Comprehensive Income (Loss)		(30.3)		(0.8)	0.3		0.4	(0.3)	(0.2)	0.1																									(30.3)	(0.8)	0.3	0.4	(0.3)	(0.2)	0.1
Ending Balance at Mar. 31, 2019						3,674.1															2,480.6									1,193.5
Ending Balance at Mar. 31, 2019		$ 19,228.5		4,089.0	2,815.2		2,432.1	2,400.1	1,242.7	2,324.9	$ 3,338.6	260.4	56.6	321.2	157.2	135.7	6,442.8		1,828.7	1,457.9		980.9	838.8	364.0	676.6	9,565.6		2,005.7	1,372.1		1,408.0	1,239.4	719.6	1,517.5	(150.7)	(5.8)	(14.8)	(13.4)	0.7	1.9	(5.3)	32.2	0.4
Ending Balance, Shares at Mar. 31, 2019											513,600,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared		$ 0.67
Beginning Balance at Dec. 31, 2018						3,569.8															2,480.6									1,089.2
Beginning Balance at Dec. 31, 2018		$ 19,059.4		4,006.1	2,580.5		2,352.8	2,297.4	1,248.0	2,315.6	$ 3,337.4	260.4	56.6	321.2	157.2	135.7	6,486.1		1,828.7	1,257.9		980.9	838.8	364.0	676.6	9,325.3		1,922.0	1,337.7		1,329.1	1,136.4	724.7	1,508.4	(120.4)	(5.0)	(15.1)	(13.8)	1.0	2.1	(5.4)	31.0	0.3
Beginning Balance, Shares at Dec. 31, 2018											513,500,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30																										(52.4)
Dividends Paid on Common Stock				(125.0)		0.0	(60.0)	(85.0)	(11.3)	(37.5)
Net Income (Loss)		1,767.6								144.5
Net Income (Loss) Attributable to Noncontrolling Interests		(0.5)								3.1
Net Income (Loss)		1,767.1	$ 133.1	293.5	192.0	347.9	248.0	247.7	148.4	147.6
Other Comprehensive Income (Loss)		(67.5)		(2.6)	0.9		1.1			0.2
Ending Balance at Sep. 30, 2019						3,917.7															2,480.6									1,437.1
Ending Balance at Sep. 30, 2019		19,997.7		4,172.0	2,973.4		2,541.9	2,459.1	1,384.4	2,422.6	$ 3,341.9	260.4	56.6	321.2	157.2	135.7	6,467.1		1,828.7	1,457.9		980.9	838.8	364.0	676.6	10,095.3		2,090.5	1,529.7		1,517.1	1,299.1	861.8	1,615.4	(187.9)	(7.6)	(14.2)	(12.7)	0.0	1.4	(5.2)	281.3	0.1
Ending Balance, Shares at Sep. 30, 2019											514,100,000
Beginning Balance at Mar. 31, 2019						3,674.1															2,480.6									1,193.5
Beginning Balance at Mar. 31, 2019		19,228.5		4,089.0	2,815.2		2,432.1	2,400.1	1,242.7	2,324.9	$ 3,338.6	260.4	56.6	321.2	157.2	135.7	6,442.8		1,828.7	1,457.9		980.9	838.8	364.0	676.6	9,565.6		2,005.7	1,372.1		1,408.0	1,239.4	719.6	1,517.5	(150.7)	(5.8)	(14.8)	(13.4)	0.7	1.9	(5.3)	32.2	0.4
Beginning Balance, Shares at Mar. 31, 2019											513,600,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock, Value		17.8									$ 2.2						15.6
Issuance of Common Stock, Shares											400,000
Common Stock Dividends		(334.5)																								(332.7)	[1]
Common Stock Dividends				(50.0)			(20.0)	(60.0)		(18.8)																		(50.0)			(20.0)	(60.0)		(18.8)
Common Stock Dividends										(1.1)																																(1.8)	(1.1)
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30		(2.5)															(3.1)																									0.6
Acquisition																																												$ 134.8	$ 134.8
Net Income (Loss)																										461.3								6.2
Net Income (Loss) Attributable to Noncontrolling Interests																																										(2.2)	1.1
Net Income (Loss)		459.1		55.5	80.6	136.0	60.3	50.6	41.9	7.3																		55.5	80.6	136.0	60.3	50.6	41.9
Other Comprehensive Income (Loss)		(80.0)		(0.9)	0.3		0.3	(0.4)	(0.3)	0.1																									(80.0)	(0.9)	0.3	0.3	(0.4)	(0.3)	0.1
Ending Balance at Jun. 30, 2019						3,810.1															2,480.6									1,329.5
Ending Balance at Jun. 30, 2019		$ 19,423.2		4,093.6	2,896.1		2,472.7	2,390.3	1,284.3	2,312.4	$ 3,340.8	260.4	56.6	321.2	157.2	135.7	6,455.3		1,828.7	1,457.9		980.9	838.8	364.0	676.6	9,694.2		2,011.2	1,452.7		1,448.3	1,230.0	761.5	1,504.9	(230.7)	(6.7)	(14.5)	(13.1)	0.3	1.6	(5.2)	163.6	0.4
Ending Balance, Shares at Jun. 30, 2019											514,000,000.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared		$ 0.67
Issuance of Common Stock, Value		$ 12.4									$ 1.1						11.3
Issuance of Common Stock, Shares											100,000
Common Stock Dividends		(333.9)																								(332.4)	[1]
Common Stock Dividends				(25.0)			(20.0)																					(25.0)			(20.0)
Common Stock Dividends										(1.1)																																(1.5)	(1.1)
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30		0.5															0.5
Acquisition																																														$ 118.8	$ 118.8
Net Income (Loss)		733.5								110.5																733.5								110.5
Net Income (Loss) Attributable to Noncontrolling Interests		0.4								0.8																																0.4	0.8
Net Income (Loss)		733.9	88.7	104.3	77.0	107.6	88.8	69.1	100.3	111.3																		104.3	77.0	107.6	88.8	69.1	100.3
Other Comprehensive Income (Loss)		42.8		(0.9)	0.3		0.4	(0.3)	(0.2)	0.0																									42.8	(0.9)	0.3	0.4	(0.3)	(0.2)
Ending Balance at Sep. 30, 2019						3,917.7															2,480.6									1,437.1
Ending Balance at Sep. 30, 2019		$ 19,997.7		4,172.0	2,973.4		2,541.9	2,459.1	1,384.4	2,422.6	$ 3,341.9	260.4	56.6	321.2	157.2	135.7	6,467.1		1,828.7	1,457.9		980.9	838.8	364.0	676.6	10,095.3		2,090.5	1,529.7		1,517.1	1,299.1	861.8	1,615.4	(187.9)	(7.6)	(14.2)	(12.7)	0.0	1.4	(5.2)	281.3	0.1
Ending Balance, Shares at Sep. 30, 2019											514,100,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared		$ 0.67
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)	0.0	1.1	(1.3)	281.0	0.6
Beginning Balance, Shares at Dec. 31, 2019		514,373,631							10,482,000		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)	[3]
Common Stock Dividends				(50.0)			(21.3)	(21.9)																				(50.0)			(21.3)	(21.9)
Common Stock Dividends										(0.7)																																(4.6)	(0.7)
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30		(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)	0.0	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)	0.0	1.1	(1.3)	281.0	0.6
Beginning Balance, Shares at Dec. 31, 2019		514,373,631							10,482,000		514,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30																										(120.6)
Dividends Paid on Common Stock				(150.0)		(5.0)	(63.7)	(65.6)	$ 0.0	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)	0.0	0.3	(1.3)	268.7	0.4
Ending Balance, Shares at Sep. 30, 2020		516,551,408							10,482,000		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)	0.0	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)	[3]
Common Stock Dividends				(50.0)			(21.2)	(21.9)																				(50.0)			(21.2)	(21.9)
Common Stock Dividends										(1.2)																																(3.2)	(1.2)
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30		(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)	0.0	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)	[3]
Common Stock Dividends				(50.0)			(21.2)	(21.8)																				(50.0)			(21.2)	(21.8)
Common Stock Dividends										(0.4)																																(2.0)	(0.4)
Forward Equity Purchase Contract Included in Current and Noncurrent Liabilities as of September 30		(103.7)															(104.0)	[4]																								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	[5]									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)	$ 0.0	$ 0.3	$ (1.3)	$ 268.7	$ 0.4
Ending Balance, Shares at Sep. 30, 2020		516,551,408							10,482,000		516,600,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared		$ 0.70

[1] Cash dividends declared per AEP common share were $0.67.

[2] Includes $(62) million related to a forward equity purchase contract associated with the issuance of Equity Units.

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

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

[5] See Note 12 - Financing Activities for additional information.