Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	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]
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)
Other Changes in Equity	(55.6)														(56.6)	[2]								(62.1)																1.0
Capital Contribution from Member			200.0															200.0
Net Income (Loss)	572.8							27.8																572.8								27.8
Net Income (Loss) Attributable to Noncontrolling Interests	1.3							1.2																																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, 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)	[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)									0.0																(1.2)
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																495.2								15.1
Net Income (Loss) Attributable to Noncontrolling Interests	4.1							1.0																																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)	0.0																									(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	515,411,847						10,482,000		515,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends Per Share, Declared	$ 0.70

[1] Cash dividends declared per AEP common share were $0.70 and $0.67 for the three months ended March 31, 2020 and 2019, respectively.

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