Business Segments (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Reportable Segment Information
Revenues	$ 4,708,000,000		$ 4,648,000,000
NET INCOME (LOSS)	631,000,000		561,000,000
Balance Sheet Information
Total Property, Plant and Equipment	65,306,000,000				64,305,000,000
Accumulated Depreciation and Amortization	20,496,000,000				20,188,000,000
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	44,810,000,000				44,117,000,000
Total Assets	60,038,000,000				59,633,000,000
Long-term Debt Due Within One Year - Affiliated	0				0
Long-term Debt Due Within One Year	2,451,000,000				2,503,000,000
Long-term Debt - Affiliated	0				0
Long-term Debt	16,778,000,000				16,181,000,000
Total Long-term Debt Outstanding	19,229,000,000				18,684,000,000
Reconciling Adjustments [Member]
Reportable Segment Information
NET INCOME (LOSS)	0		0
Balance Sheet Information
Total Property, Plant and Equipment	(280,000,000)	[1]			(272,000,000)	[1]
Accumulated Depreciation and Amortization	(102,000,000)	[1]			(99,000,000)	[1]
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	(178,000,000)	[1]			(173,000,000)	[1]
Total Assets	(21,027,000,000)	[1],[2]			(20,346,000,000)	[1],[2]
Long-term Debt Due Within One Year - Affiliated	(197,000,000)				(197,000,000)
Long-term Debt Due Within One Year	0				0
Long-term Debt - Affiliated	(52,000,000)				(52,000,000)
Long-term Debt	0				0
Total Long-term Debt Outstanding	(249,000,000)				(249,000,000)
Vertically Integrated Utilities [Member]
Reportable Segment Information
Sales Revenue, Net	2,487,000,000		2,549,000,000	[3]
Revenues	2,505,000,000		2,586,000,000
NET INCOME (LOSS)	300,000,000		279,000,000
Balance Sheet Information
Total Property, Plant and Equipment	40,890,000,000				39,402,000,000
Accumulated Depreciation and Amortization	13,335,000,000				12,773,000,000
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	27,555,000,000				26,629,000,000
Total Assets	35,075,000,000				33,750,000,000
Long-term Debt Due Within One Year - Affiliated	111,000,000				111,000,000
Long-term Debt Due Within One Year	1,291,000,000				1,352,000,000
Long-term Debt - Affiliated	20,000,000				20,000,000
Long-term Debt	9,393,000,000				8,634,000,000
Total Long-term Debt Outstanding	10,815,000,000				10,117,000,000
Vertically Integrated Utilities [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net	18,000,000		37,000,000	[3]
Transmission And Distribution Companies [Member]
Reportable Segment Information
Sales Revenue, Net	1,206,000,000		1,161,000,000
Revenues	1,270,000,000		1,215,000,000
NET INCOME (LOSS)	97,000,000		97,000,000
Balance Sheet Information
Total Property, Plant and Equipment	13,251,000,000				13,024,000,000
Accumulated Depreciation and Amortization	3,520,000,000				3,481,000,000
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	9,731,000,000				9,543,000,000
Total Assets	14,403,000,000				14,495,000,000
Long-term Debt Due Within One Year - Affiliated	0				0
Long-term Debt Due Within One Year	414,000,000				405,000,000
Long-term Debt - Affiliated	0				0
Long-term Debt	5,105,000,000				5,256,000,000
Total Long-term Debt Outstanding	5,519,000,000				5,661,000,000
Transmission And Distribution Companies [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net	64,000,000		54,000,000
AEP Transmission Holdco [Member]
Reportable Segment Information
Sales Revenue, Net	22,000,000		12,000,000
Revenues	58,000,000		28,000,000
NET INCOME (LOSS)	37,000,000		24,000,000
Balance Sheet Information
Total Property, Plant and Equipment	2,980,000,000				2,714,000,000
Accumulated Depreciation and Amortization	28,000,000				25,000,000
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	2,952,000,000				2,689,000,000
Total Assets	3,736,000,000				3,575,000,000
Long-term Debt Due Within One Year - Affiliated	0				0
Long-term Debt Due Within One Year	0				0
Long-term Debt - Affiliated	0				0
Long-term Debt	1,207,000,000				1,153,000,000
Total Long-term Debt Outstanding	1,207,000,000				1,153,000,000
AEP Transmission Holdco [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net	36,000,000		16,000,000
Generation And Marketing [Member]
Reportable Segment Information
Sales Revenue, Net	859,000,000		821,000,000	[3]
Revenues	1,170,000,000		1,251,000,000
NET INCOME (LOSS)	187,000,000		163,000,000
Balance Sheet Information
Total Property, Plant and Equipment	7,414,000,000				8,394,000,000
Accumulated Depreciation and Amortization	3,309,000,000				3,603,000,000
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	4,105,000,000				4,791,000,000
Total Assets	5,706,000,000				6,329,000,000
Long-term Debt Due Within One Year - Affiliated	86,000,000				86,000,000
Long-term Debt Due Within One Year	740,000,000				740,000,000
Long-term Debt - Affiliated	32,000,000				32,000,000
Long-term Debt	148,000,000				217,000,000
Total Long-term Debt Outstanding	1,006,000,000				1,075,000,000
Generation And Marketing [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net	311,000,000		430,000,000	[3]
AEP River Operations [Member]
Reportable Segment Information
Sales Revenue, Net	128,000,000		146,000,000
Revenues	139,000,000		165,000,000
NET INCOME (LOSS)	11,000,000		3,000,000
Balance Sheet Information
Total Property, Plant and Equipment	701,000,000				700,000,000
Accumulated Depreciation and Amortization	223,000,000				217,000,000
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	478,000,000				483,000,000
Total Assets	743,000,000				749,000,000
Long-term Debt Due Within One Year - Affiliated	0				0
Long-term Debt Due Within One Year	3,000,000				3,000,000
Long-term Debt - Affiliated	0				0
Long-term Debt	80,000,000				80,000,000
Total Long-term Debt Outstanding	83,000,000				83,000,000
AEP River Operations [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net	11,000,000		19,000,000
All Other [Member]
Reportable Segment Information
Sales Revenue, Net	6,000,000	[4]	10,000,000	[4]
Revenues	26,000,000	[4]	26,000,000	[4]
NET INCOME (LOSS)	(1,000,000)	[4]	(5,000,000)	[4]
Balance Sheet Information
Total Property, Plant and Equipment	350,000,000	[4]			343,000,000	[4]
Accumulated Depreciation and Amortization	183,000,000	[4]			188,000,000	[4]
TOTAL PROPERTY, PLANT AND EQUIPMENT - NET	167,000,000	[4]			155,000,000	[4]
Total Assets	21,402,000,000	[4]			21,081,000,000	[4]
Long-term Debt Due Within One Year - Affiliated	0	[4]			0	[4]
Long-term Debt Due Within One Year	3,000,000	[4]			3,000,000	[4]
Long-term Debt - Affiliated	0	[4]			0	[4]
Long-term Debt	845,000,000	[4]			841,000,000	[4]
Total Long-term Debt Outstanding	848,000,000	[4]			844,000,000	[4]
All Other [Member] | Significant Reconciling Items [Member]
Reportable Segment Information
Sales Revenue, Net	20,000,000	[4]	16,000,000	[4]
Consolidation, Eliminations [Member]
Reportable Segment Information
Sales Revenue, Net	0		(51,000,000)	[5]
Revenues	(460,000,000)		(623,000,000)
Consolidation, Eliminations [Member] | Reconciling Adjustments [Member]
Reportable Segment Information
Sales Revenue, Net	$ (460,000,000)		$ (572,000,000)

[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.