Derivatives and Hedging (Details) (USD $)	3 Months Ended				12 Months Ended
	Mar. 31, 2012		Mar. 31, 2011		Dec. 31, 2011
Commodity:
Power (In MWHs)	524,000,000				609,000,000
Coal (In Tons)	19,000,000				21,000,000
Natural Gas (In MMBtus)	113,000,000				100,000,000
Heating Oil and Gasoline (In Gallons)	4,000,000				6,000,000
Interest Rate	$ 202,000,000				$ 226,000,000
Interest Rate and Foreign Currency	803,000,000				907,000,000
Fair Value of Derivative Instruments
Current Risk Management Assets	246,000,000				193,000,000
Long-term Risk Management Assets	425,000,000				403,000,000
Total Assets	671,000,000				596,000,000
Current Risk Management Liabilities	185,000,000				150,000,000
Long-term Risk Management Assets	239,000,000				195,000,000
Total Liabilities	424,000,000				345,000,000
Total MTM Derivative Contract Net Assets (Liabilities)	247,000,000				251,000,000
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	6,000,000		32,000,000
Total Accumulated Other Comprehensive Income (Loss) Activity for Cash Flow Hedges
Beginning Balance in AOCI	(23,000,000)		11,000,000		11,000,000
Changes in Fair Value Recognized in AOCI	(19,000,000)		1,000,000
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Ending Balance in AOCI	(34,000,000)		12,000,000		(23,000,000)
Impact of Cash Flow Hedges on the Condensed Balance Sheet
Hedging Assets	29,000,000	[1]			20,000,000	[1]
Hedging Liabilities	70,000,000	[1]			67,000,000	[1]
AOCI Gain (Loss) Net of Tax	(34,000,000)		12,000,000		(23,000,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months	(17,000,000)				(5,000,000)
Collateral Triggering Events [Abstract]
Liabilities for Derivative Contracts with Credit Downgrade Triggers	21,000,000				32,000,000
Amount of Collateral AEP Subsidiaries Would Have Been Required to Post	50,000,000				39,000,000
Amount Attributable to RTO and ISO Activities	48,000,000				38,000,000
Liabilities for Contracts with Cross Default Provisions Prior to Contractural Netting Arrangements	716,000,000				515,000,000
Posted Cash Collateral Related to Contracts with Cross Default Provisions	2,000,000				56,000,000
Additional Settlement Liability if Cross Default Provision is Triggered	354,000,000				291,000,000
Derivatives and Hedging (Textuals) [Abstract]
Cash Collateral Received Netted Against Risk Management Assets	24,000,000				26,000,000
Cash Collateral Paid Netted Against Risk Management Liabilities	109,000,000				133,000,000
Maximum Length of Time for Hedging Exposure (in months)	42
Gain on Fair Value Hedging Instrument	1,000,000		4,000,000
Loss on Fair Value Portion of Long Term Debt	1,000,000		4,000,000
Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Total Assets	616,000,000	[2],[3]			548,000,000	[2],[4]
Total Liabilities	354,000,000	[2],[3]			278,000,000	[2],[4]
Fair Value Hedges [Member]
Fair Value of Derivative Instruments
Total Assets	1,000,000
Other [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	(1,094,000,000)	[5]			(683,000,000)	[5]
Long-term Risk Management Assets	(354,000,000)	[5]			(253,000,000)	[5]
Total Assets	(1,448,000,000)	[5]			(936,000,000)	[5]
Current Risk Management Liabilities	(1,166,000,000)	[5]			(746,000,000)	[5]
Long-term Risk Management Assets	(392,000,000)	[5]			(325,000,000)	[5]
Total Liabilities	(1,558,000,000)	[5]			(1,071,000,000)	[5]
Total MTM Derivative Contract Net Assets (Liabilities)	110,000,000	[5]			135,000,000	[5]
Interest Rate and Foreign Currency [Member]
Total Accumulated Other Comprehensive Income (Loss) Activity for Cash Flow Hedges
Beginning Balance in AOCI	(20,000,000)		4,000,000		4,000,000
Changes in Fair Value Recognized in AOCI	1,000,000		(1,000,000)
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Ending Balance in AOCI	(18,000,000)		4,000,000		(20,000,000)
Impact of Cash Flow Hedges on the Condensed Balance Sheet
Hedging Assets	0	[1]			0	[1]
Hedging Liabilities	15,000,000	[1]			42,000,000	[1]
AOCI Gain (Loss) Net of Tax	(18,000,000)		4,000,000		(20,000,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months	(3,000,000)				(2,000,000)
Interest Rate and Foreign Currency [Member] | Hedging Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	1,000,000	[6]			0	[6]
Long-term Risk Management Assets	0	[6]			0	[6]
Total Assets	1,000,000	[6]			0	[6]
Current Risk Management Liabilities	13,000,000	[6]			20,000,000	[6]
Long-term Risk Management Assets	2,000,000	[6]			22,000,000	[6]
Total Liabilities	15,000,000	[6]			42,000,000	[6]
Total MTM Derivative Contract Net Assets (Liabilities)	(14,000,000)	[6]			(42,000,000)	[6]
Commodity [Member]
Total Accumulated Other Comprehensive Income (Loss) Activity for Cash Flow Hedges
Beginning Balance in AOCI	(3,000,000)		7,000,000		7,000,000
Changes in Fair Value Recognized in AOCI	(20,000,000)		2,000,000
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Ending Balance in AOCI	(16,000,000)		8,000,000		(3,000,000)
Impact of Cash Flow Hedges on the Condensed Balance Sheet
Hedging Assets	29,000,000	[1]			20,000,000	[1]
Hedging Liabilities	55,000,000	[1]			25,000,000	[1]
AOCI Gain (Loss) Net of Tax	(16,000,000)		8,000,000		(3,000,000)
Portion Expected to be Reclassified to Net Income During the Next Twelve Months	(14,000,000)				(3,000,000)
Commodity [Member] | Risk Management Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	1,298,000,000	[6]			852,000,000	[6]
Long-term Risk Management Assets	758,000,000	[6]			641,000,000	[6]
Total Assets	2,056,000,000	[6]			1,493,000,000	[6]
Current Risk Management Liabilities	1,275,000,000	[6]			847,000,000	[6]
Long-term Risk Management Assets	604,000,000	[6]			483,000,000	[6]
Total Liabilities	1,879,000,000	[6]			1,330,000,000	[6]
Total MTM Derivative Contract Net Assets (Liabilities)	177,000,000	[6]			163,000,000	[6]
Commodity [Member] | Hedging Contracts [Member]
Fair Value of Derivative Instruments
Current Risk Management Assets	41,000,000	[6]			24,000,000	[6]
Long-term Risk Management Assets	21,000,000	[6]			15,000,000	[6]
Total Assets	62,000,000	[6]			39,000,000	[6]
Current Risk Management Liabilities	63,000,000	[6]			29,000,000	[6]
Long-term Risk Management Assets	25,000,000	[6]			15,000,000	[6]
Total Liabilities	88,000,000	[6]			44,000,000	[6]
Total MTM Derivative Contract Net Assets (Liabilities)	(26,000,000)	[6]			(5,000,000)	[6]
Other Revenues [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	3,000,000		2,000,000
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	(1,000,000)		(1,000,000)
Other Revenues [Member] | Interest Rate and Foreign Currency [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	0		0
Other Revenues [Member] | Commodity [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	(1,000,000)		(1,000,000)
Interest Expense [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	1,000,000		1,000,000
Interest Expense [Member] | Interest Rate and Foreign Currency [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	1,000,000		1,000,000
Interest Expense [Member] | Commodity [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	0		0
Purchased Electricity for Resale [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	7,000,000		0
Purchased Electricity for Resale [Member] | Interest Rate and Foreign Currency [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	0		0
Purchased Electricity for Resale [Member] | Commodity [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	7,000,000		0
Utility Operations Revenues [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	10,000,000		20,000,000
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	0		0
Utility Operations Revenues [Member] | Interest Rate and Foreign Currency [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	0		0
Utility Operations Revenues [Member] | Commodity [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	0		0
Regulatory Assets [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	(21,000,000)	[7]	2,000,000	[7]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	1,000,000	[7]	0	[7]
Regulatory Assets [Member] | Interest Rate and Foreign Currency [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	0	[7]	0	[7]
Regulatory Assets [Member] | Commodity [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	1,000,000	[7]	0	[7]
Regulatory Liabilities [Member]
Amount of Gain (Loss) Recognized on Risk Management Contracts
Amount of Gain (Loss) Recognized on Risk Management Contracts	14,000,000	[7]	8,000,000	[7]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	0	[7]	0	[7]
Regulatory Liabilities [Member] | Interest Rate and Foreign Currency [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	0	[7]	0	[7]
Regulatory Liabilities [Member] | Commodity [Member]
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet:
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income/within Balance Sheet	$ 0	[7]	$ 0	[7]

[1] Hedging Assets and Hedging Liabilities are included in Risk Management Assets and Liabilities on the condensed balance sheets.

[2] Amounts in ''Other'' column primarily represent counterparty netting of risk management and hedging contracts and associated cash collateral under the accounting guidance for ''Derivatives and Hedging.''

[3] The March 31, 2012 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 1 matures $3 million in 2012, $12 million in periods 2013-2015 and ($7) million in periods 2016-2018; Level 2 matures $4 million in 2012, $49 million in periods 2013-2015, $18 million in periods 2016-2017 and $7 million in periods 2018-2030; Level 3 matures $3 million in 2012, $46 million in periods 2013-2015, $18 million in periods 2016-2017 and $24 million in periods 2018-2030. Risk management commodity contracts are substantially comprised of power contracts.

[4] The December 31, 2011 maturity of the net fair value of risk management contracts prior to cash collateral, assets/(liabilities), is as follows: Level 1 matures $3 million in 2012, $7 million in periods 2013-2015 and ($6) million in periods 2016-2018; Level 2 matures $21 million in 2012, $50 million in periods 2013-2015, $11 million in periods 2016-2017 and $8 million in periods 2018-2030; Level 3 matures ($19) million in 2012, $44 million in periods 2013-2015, $18 million in periods 2016-2017 and $26 million in periods 2018-2030. Risk management commodity contracts are substantially comprised of power contracts.

[5] Amounts include counterparty netting of risk management and hedging contracts and associated cash collateral in accordance with the accounting guidance for "Derivatives and Hedging." Amounts also include de-designated risk management contracts.

[6] Derivative instruments within these categories are reported gross. These instruments are subject to master netting agreements and are presented on the condensed balance sheets on a net basis in accordance with the accounting guidance for "Derivatives and Hedging."

[7]         Represents realized and unrealized gains and losses subject to regulatory accounting treatment recorded as either current or noncurrent on the condensed balance sheets.