Business Segments (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014		Jun. 30, 2015	Jun. 30, 2014		Dec. 31, 2014
Reportable Segment Information
Revenues		$ 3,942	$ 4,044		$ 8,650	$ 8,692
NET INCOME (LOSS)		431	391		1,062	952
Balance Sheet Information
Total Property, Plant and Equipment		64,602			64,602			$ 64,305
Accumulated Depreciation and Amortization		19,589			19,589			20,188
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		45,013			45,013			44,117
Total Assets		60,938			60,938			59,633
Long-term Debt Due Within One Year - Affiliated		0			0			0
Long-term Debt Due Within One Year		1,817			1,817			2,503
Long-term Debt - Affiliated		0			0			0
Long-term Debt		17,761			17,761			16,181
Total Long-term Debt Outstanding		19,578			19,578			18,684
Reconciling Adjustments [Member]
Reportable Segment Information
NET INCOME (LOSS)		0	0		0	0
Balance Sheet Information
Total Property, Plant and Equipment	[1]	(279)			(279)			(272)
Accumulated Depreciation and Amortization	[1]	(105)			(105)			(99)
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	[1]	(174)			(174)			(173)
Total Assets	[1],[2]	(20,788)			(20,788)			(20,346)
Long-term Debt Due Within One Year - Affiliated		0			0			(197)
Long-term Debt Due Within One Year		0			0			0
Long-term Debt - Affiliated		(52)			(52)			(52)
Long-term Debt		0			0			0
Total Long-term Debt Outstanding		(52)			(52)			(249)
Vertically Integrated Utilities [Member]
Reportable Segment Information
Sales Revenue, Net		2,159	2,236	[3]	4,646	4,785	[3]
Revenues		2,183	2,252		4,688	4,838
NET INCOME (LOSS)		208	155		508	434
Balance Sheet Information
Total Property, Plant and Equipment		39,561			39,561			39,402
Accumulated Depreciation and Amortization		12,343			12,343			12,773
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		27,218			27,218			26,629
Total Assets		35,316			35,316			33,750
Long-term Debt Due Within One Year - Affiliated		0			0			111
Long-term Debt Due Within One Year		894			894			1,352
Long-term Debt - Affiliated		20			20			20
Long-term Debt		10,146			10,146			8,634
Total Long-term Debt Outstanding		11,060			11,060			10,117
Vertically Integrated Utilities [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net		24	16	[3]	42	53	[3]
Transmission And Distribution Utilities [Member]
Reportable Segment Information
Sales Revenue, Net		1,008	1,064		2,214	2,225
Revenues		1,061	1,134		2,331	2,349
NET INCOME (LOSS)		78	90		175	187
Balance Sheet Information
Total Property, Plant and Equipment		13,506			13,506			13,024
Accumulated Depreciation and Amortization		3,565			3,565			3,481
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		9,941			9,941			9,543
Total Assets		14,351			14,351			14,495
Long-term Debt Due Within One Year - Affiliated		0			0			0
Long-term Debt Due Within One Year		678			678			405
Long-term Debt - Affiliated		0			0			0
Long-term Debt		4,729			4,729			5,256
Total Long-term Debt Outstanding		5,407			5,407			5,661
Transmission And Distribution Utilities [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net		53	70		117	124
AEP Transmission Holdco [Member]
Reportable Segment Information
Sales Revenue, Net		25	21		47	33
Revenues		99	57		157	85
NET INCOME (LOSS)		65	47		102	71
Balance Sheet Information
Total Property, Plant and Equipment		3,275			3,275			2,714
Accumulated Depreciation and Amortization		34			34			25
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		3,241			3,241			2,689
Total Assets		4,036			4,036			3,575
Long-term Debt Due Within One Year - Affiliated		0			0			0
Long-term Debt Due Within One Year		0			0			0
Long-term Debt - Affiliated		0			0			0
Long-term Debt		1,315			1,315			1,153
Total Long-term Debt Outstanding		1,315			1,315			1,153
AEP Transmission Holdco [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net		74	36		110	52
Generation And Marketing [Member]
Reportable Segment Information
Sales Revenue, Net		628	573	[3]	1,487	1,394	[3]
Revenues		801	913		1,971	2,164
NET INCOME (LOSS)		82	98		269	261
Balance Sheet Information
Total Property, Plant and Equipment		7,456			7,456			8,394
Accumulated Depreciation and Amortization		3,344			3,344			3,603
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		4,112			4,112			4,791
Total Assets		5,668			5,668			6,329
Long-term Debt Due Within One Year - Affiliated		0			0			86
Long-term Debt Due Within One Year		240			240			740
Long-term Debt - Affiliated		32			32			32
Long-term Debt		648			648			217
Total Long-term Debt Outstanding		920			920			1,075
Generation And Marketing [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net		173	340	[3]	484	770	[3]
AEP River Operations [Member]
Reportable Segment Information
Sales Revenue, Net		115	140		243	286
Revenues		128	160		267	325
NET INCOME (LOSS)		1	3		12	6
Balance Sheet Information
Total Property, Plant and Equipment		726			726			700
Accumulated Depreciation and Amortization		227			227			217
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET		499			499			483
Total Assets		756			756			749
Long-term Debt Due Within One Year - Affiliated		0			0			0
Long-term Debt Due Within One Year		3			3			3
Long-term Debt - Affiliated		0			0			0
Long-term Debt		79			79			80
Total Long-term Debt Outstanding		82			82			83
AEP River Operations [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net		13	20		24	39
All Other [Member]
Reportable Segment Information
Sales Revenue, Net	[4]	7	10		13	20
Revenues	[4]	24	22		50	48
NET INCOME (LOSS)	[4]	(3)	(2)		(4)	(7)
Balance Sheet Information
Total Property, Plant and Equipment	[4]	357			357			343
Accumulated Depreciation and Amortization	[4]	181			181			188
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	[4]	176			176			155
Total Assets	[4]	21,599			21,599			21,081
Long-term Debt Due Within One Year - Affiliated	[4]	0			0			0
Long-term Debt Due Within One Year	[4]	2			2			3
Long-term Debt - Affiliated	[4]	0			0			0
Long-term Debt	[4]	844			844			841
Total Long-term Debt Outstanding	[4]	846			846			$ 844
All Other [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net	[4]	17	12		37	28
Consolidation, Eliminations [Member]
Reportable Segment Information
Sales Revenue, Net	[5]	0	0		0	(51)
Revenues		(354)	(494)		(814)	(1,117)
Consolidation, Eliminations [Member] | Reconciling Adjustments [Member]
Reportable Segment Information
Sales Revenue, Net		$ (354)	$ (494)		$ (814)	$ (1,066)

[1] Includes eliminations due to an intercompany capital lease.

[2] Reconciling Adjustments for Total Assets primarily include the elimination of intercompany advances to affiliates and intercompany accounts receivable along with the elimination of AEP's investments in subsidiary companies.

[3] Includes the impact of corporate separation of OPCo's generation assets and liabilities that took effect December 31, 2013, as well as the impact of the termination of the Interconnection Agreement effective January 1, 2014.

[4] Corporate and Other primarily includes the purchasing of receivables from certain AEP utility subsidiaries. This segment also includes Parent's guarantee revenue received from affiliates, investment income, interest income and interest expense and other nonallocated costs.

[5] Reconciling Adjustments for External Customers primarily include eliminations as a result of corporate separation in Ohio.