Variable Interest Entities (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended			12 Months Ended
		Jun. 30, 2015		Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014	Dec. 31, 2014
Variable Interest Entities (Textuals) [Abstract]
Securitization Bonds		$ 2,200,000			$ 2,200,000			$ 2,380,000
Securitized Transition Assets		1,931,000			$ 1,931,000			2,072,000
AEP Credit, Inc. [Member]
Variable Interest Entities (Textuals) [Abstract]
Minimum Percentage of Equity AEP Provides					5.00%
Percentage of Short Term Borrowing Needs in Excess of Third Party Financings					20.00%
AEP Texas Central Transition Funding Co [Member]
Variable Interest Entities (Textuals) [Abstract]
Securitization Bonds		1,600,000			$ 1,600,000			1,800,000
Securitized Transition Assets		1,500,000			1,500,000			1,600,000
Protected Cell Of Energy Insurance Services, Inc. [Member]
Variable Interest Entities (Textuals) [Abstract]
Insurance Premium Expense to Protected Cell		0		$ 1,400	14,000		$ 18,000
Transource Energy [Member]
Variable Interest Entities (Textuals) [Abstract]
Proceeds from Partnership Contribution					17,000			23,000
PATH West Virginia Transmission Co, LLC [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		21,000			21,000			21,000
Maximum Exposure		21,000			21,000			21,000
Advance Due to Parent [Member] | Dolet Hills Lignite Co, LLC [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		56,000			56,000			56,000
Maximum Exposure		56,000			56,000			56,000
Capital Contribution From Parent [Member] | PATH West Virginia Transmission Co, LLC [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		19,000			19,000			19,000
Maximum Exposure		19,000			19,000			19,000
Retained Earnings [Member] | PATH West Virginia Transmission Co, LLC [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		2,000			2,000			2,000
Maximum Exposure		2,000			2,000			2,000
SWEPCo's Guarantee Of Debt [Member] | Dolet Hills Lignite Co, LLC [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		0			0			0
Maximum Exposure		50,000			50,000			48,000
Current Assets [Member] | AEP Credit, Inc. [Member]
ASSETS
Assets		986,000			986,000			980,000
Current Assets [Member] | AEP Texas Central Transition Funding Co [Member]
ASSETS
Assets		220,000			220,000			239,000
Current Assets [Member] | Protected Cell Of Energy Insurance Services, Inc. [Member]
ASSETS
Assets		155,000			155,000			149,000
Current Assets [Member] | Transource Energy [Member]
ASSETS
Assets		10,000			10,000			2,000
Net Property Plant And Equipment [Member] | AEP Credit, Inc. [Member]
ASSETS
Assets		0			0			0
Net Property Plant And Equipment [Member] | AEP Texas Central Transition Funding Co [Member]
ASSETS
Assets		0			0			0
Net Property Plant And Equipment [Member] | Protected Cell Of Energy Insurance Services, Inc. [Member]
ASSETS
Assets		0			0			0
Net Property Plant And Equipment [Member] | Transource Energy [Member]
ASSETS
Assets		137,000			137,000			98,000
Other Non Current Assets [Member] | AEP Credit, Inc. [Member]
ASSETS
Assets		0			0			0
Other Non Current Assets [Member] | AEP Texas Central Transition Funding Co [Member]
ASSETS
Assets		1,533,000	[1]		1,533,000	[1]		1,654,000	[2]
Variable Interest Entities (Textuals) [Abstract]
Intercompany Item Eliminated in Consolidation		72,000			72,000			75,000
Other Non Current Assets [Member] | Protected Cell Of Energy Insurance Services, Inc. [Member]
ASSETS
Assets		1,000			1,000			2,000
Other Non Current Assets [Member] | Transource Energy [Member]
ASSETS
Assets		5,000			5,000			4,000
Total Assets [Member] | AEP Credit, Inc. [Member]
ASSETS
Assets		986,000			986,000			980,000
Total Assets [Member] | AEP Texas Central Transition Funding Co [Member]
ASSETS
Assets		1,753,000			1,753,000			1,893,000
Total Assets [Member] | Protected Cell Of Energy Insurance Services, Inc. [Member]
ASSETS
Assets		156,000			156,000			151,000
Total Assets [Member] | Transource Energy [Member]
ASSETS
Assets		152,000			152,000			104,000
Current Liabilities [Member] | AEP Credit, Inc. [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		886,000			886,000			894,000
Current Liabilities [Member] | AEP Texas Central Transition Funding Co [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		326,000			326,000			322,000
Current Liabilities [Member] | Protected Cell Of Energy Insurance Services, Inc. [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		43,000			43,000			44,000
Current Liabilities [Member] | Transource Energy [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		28,000			28,000			21,000
Noncurrent Liabilities [Member] | AEP Credit, Inc. [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		0			0			0
Noncurrent Liabilities [Member] | AEP Texas Central Transition Funding Co [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		1,409,000			1,409,000			1,553,000
Noncurrent Liabilities [Member] | Protected Cell Of Energy Insurance Services, Inc. [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		67,000			67,000			62,000
Noncurrent Liabilities [Member] | Transource Energy [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		70,000			70,000			55,000
Equity [Member] | AEP Credit, Inc. [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		100,000			100,000			86,000
Equity [Member] | AEP Texas Central Transition Funding Co [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		18,000			18,000			18,000
Equity [Member] | Protected Cell Of Energy Insurance Services, Inc. [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		46,000			46,000			45,000
Equity [Member] | Transource Energy [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		54,000			54,000			28,000
Total Liabilities And Equity [Member] | AEP Credit, Inc. [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		986,000			986,000			980,000
Total Liabilities And Equity [Member] | AEP Texas Central Transition Funding Co [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		1,753,000			1,753,000			1,893,000
Total Liabilities And Equity [Member] | Protected Cell Of Energy Insurance Services, Inc. [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		156,000			156,000			151,000
Total Liabilities And Equity [Member] | Transource Energy [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		$ 152,000			$ 152,000			104,000
Great Plains Energy Inc. [Member] | Transource Energy [Member]
Variable Interest Entities (Textuals) [Abstract]
Equity and Voting Ownership Percentage		13.50%			13.50%
Transource Energy [Member]
Variable Interest Entities (Textuals) [Abstract]
Equity and Voting Ownership Percentage		86.50%			86.50%
Appalachian Power Co [Member]
Related Party Transaction, Due from (to) Related Party, Current		$ (33,703)			$ (33,703)
Variable Interest Entities (Textuals) [Abstract]
Securitized Transition Assets		339,020			339,020			350,170
Appalachian Power Co [Member] | Appalachian Consumer Rate Relief Funding [Member]
Variable Interest Entities (Textuals) [Abstract]
Securitization Bonds		357,000			357,000			368,000
Securitized Transition Assets		339,000			339,000			350,000
Intercompany Item Eliminated in Consolidation		4,000			4,000			4,000
Appalachian Power Co [Member] | Billings from American Electric Power Service Corporation [Member]
Billings from Affiliates
Billings from VIE		52,722		53,959	100,970		104,096
Variable Interest Entities (Textuals) [Abstract]
Billings from VIE		52,722		53,959	100,970		104,096
Appalachian Power Co [Member] | Carrying Amount in AEPSC's Accounts Payable [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		19,141			19,141			30,692
Maximum Exposure		19,141			19,141			30,692
Appalachian Power Co [Member] | Current Assets [Member] | Appalachian Consumer Rate Relief Funding [Member]
ASSETS
Assets		19,145			19,145			18,099
Appalachian Power Co [Member] | Other Non Current Assets [Member] | Appalachian Consumer Rate Relief Funding [Member]
ASSETS
Assets	[3]	346,809			346,809			358,264
Appalachian Power Co [Member] | Total Assets [Member] | Appalachian Consumer Rate Relief Funding [Member]
ASSETS
Assets		365,954			365,954			376,363
Appalachian Power Co [Member] | Current Liabilities [Member] | Appalachian Consumer Rate Relief Funding [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		26,912			26,912			26,809
Appalachian Power Co [Member] | Noncurrent Liabilities [Member] | Appalachian Consumer Rate Relief Funding [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		337,316			337,316			347,652
Appalachian Power Co [Member] | Equity [Member] | Appalachian Consumer Rate Relief Funding [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		1,726			1,726			1,902
Appalachian Power Co [Member] | Total Liabilities And Equity [Member] | Appalachian Consumer Rate Relief Funding [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		365,954			365,954			376,363
Indiana Michigan Power Co [Member]
Related Party Transaction, Due from (to) Related Party, Current		(127,154)			(127,154)
Indiana Michigan Power Co [Member] | DCC Fuel [Member]
Variable Interest Entities (Textuals) [Abstract]
Payments Made by I&M to DCC Fuel		34,000		32,000	57,000		56,000
Indiana Michigan Power Co [Member] | Billings from AEP Generating Co [Member]
Billings from Affiliates
Billings from VIE		59,993		65,190	114,958		135,612
Variable Interest Entities (Textuals) [Abstract]
Billings from VIE		59,993		65,190	114,958		135,612
Indiana Michigan Power Co [Member] | Billings from American Electric Power Service Corporation [Member]
Billings from Affiliates
Billings from VIE		31,134		30,103	64,636		62,073
Variable Interest Entities (Textuals) [Abstract]
Billings from VIE		31,134		30,103	64,636		62,073
Indiana Michigan Power Co [Member] | Carrying Amount in AEPSC's Accounts Payable [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		11,173			11,173			22,480
Maximum Exposure		11,173			11,173			22,480
Indiana Michigan Power Co [Member] | Carrying Amount in AEGCo's Accounts Payable [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		21,084			21,084			20,031
Maximum Exposure		21,084			21,084			20,031
Indiana Michigan Power Co [Member] | Current Assets [Member] | DCC Fuel [Member]
ASSETS
Assets		114,522			114,522			97,361
Indiana Michigan Power Co [Member] | Net Property Plant And Equipment [Member] | DCC Fuel [Member]
ASSETS
Assets		219,786			219,786			158,121
Indiana Michigan Power Co [Member] | Other Non Current Assets [Member] | DCC Fuel [Member]
ASSETS
Assets		117,702			117,702			79,705
Indiana Michigan Power Co [Member] | Total Assets [Member] | DCC Fuel [Member]
ASSETS
Assets		452,010			452,010			335,187
Indiana Michigan Power Co [Member] | Current Liabilities [Member] | DCC Fuel [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		109,491			109,491			86,026
Indiana Michigan Power Co [Member] | Noncurrent Liabilities [Member] | DCC Fuel [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		342,519			342,519			249,161
Indiana Michigan Power Co [Member] | Total Liabilities And Equity [Member] | DCC Fuel [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		452,010			452,010			335,187
Public Service Co Of Oklahoma [Member]
Related Party Transaction, Due from (to) Related Party, Current		64,212			64,212
Public Service Co Of Oklahoma [Member] | Billings from American Electric Power Service Corporation [Member]
Billings from Affiliates
Billings from VIE		24,442		22,889	47,966		47,329
Variable Interest Entities (Textuals) [Abstract]
Billings from VIE		24,442		22,889	47,966		47,329
Public Service Co Of Oklahoma [Member] | Carrying Amount in AEPSC's Accounts Payable [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		9,017			9,017			15,338
Maximum Exposure		9,017			9,017			15,338
Southwestern Electric Power Co [Member]
Related Party Transaction, Due from (to) Related Party, Current		179,709			179,709
Southwestern Electric Power Co [Member] | Sabine Mining Co [Member]
Billings from Affiliates
Billings from VIE		41,000		41,000	83,000		80,000
Variable Interest Entities (Textuals) [Abstract]
Billings from VIE		41,000		41,000	83,000		80,000
Southwestern Electric Power Co [Member] | Dolet Hills Lignite Co, LLC [Member]
Related Party Transaction, Due from (to) Related Party, Current		56,000			56,000			56,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		13,183			13,183			11,462
Maximum Exposure		119,591			119,591			115,796
Billings from Affiliates
Billings from VIE		15,000		6,000	29,000		8,000
Variable Interest Entities (Textuals) [Abstract]
Billings from VIE		15,000		6,000	$ 29,000		8,000
Percentage of VIE Sales of Lignite Produced					50.00%
Percentage of DHLCs Debt Guaranteed by Each SWEPCo and CLECO					50.00%
Percentage Of VIE Management Fee Received					100.00%
Southwestern Electric Power Co [Member] | Billings from American Electric Power Service Corporation [Member]
Billings from Affiliates
Billings from VIE		31,900		32,718	$ 63,414		65,741
Variable Interest Entities (Textuals) [Abstract]
Billings from VIE		31,900		32,718	63,414		65,741
Southwestern Electric Power Co [Member] | Carrying Amount in AEPSC's Accounts Payable [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		12,114			12,114			20,772
Maximum Exposure		12,114			12,114			20,772
Southwestern Electric Power Co [Member] | Capital Contribution From Parent [Member] | Dolet Hills Lignite Co, LLC [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		7,643			7,643			7,643
Maximum Exposure		7,643			7,643			7,643
Southwestern Electric Power Co [Member] | Retained Earnings [Member] | Dolet Hills Lignite Co, LLC [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		5,540			5,540			3,819
Maximum Exposure		5,540			5,540			3,819
Southwestern Electric Power Co [Member] | SWEPCo's Guarantee Of Debt [Member] | Dolet Hills Lignite Co, LLC [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		0			0			0
Maximum Exposure	[4]	106,408			106,408			104,334
Southwestern Electric Power Co [Member] | Current Assets [Member] | Sabine Mining Co [Member]
ASSETS
Assets		57,592			57,592			67,981
Southwestern Electric Power Co [Member] | Net Property Plant And Equipment [Member] | Sabine Mining Co [Member]
ASSETS
Assets		142,265			142,265			145,491
Southwestern Electric Power Co [Member] | Other Non Current Assets [Member] | Sabine Mining Co [Member]
ASSETS
Assets		59,717			59,717			51,578
Southwestern Electric Power Co [Member] | Total Assets [Member] | Sabine Mining Co [Member]
ASSETS
Assets		259,574			259,574			265,050
Southwestern Electric Power Co [Member] | Current Liabilities [Member] | Sabine Mining Co [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		28,122			28,122			36,286
Southwestern Electric Power Co [Member] | Noncurrent Liabilities [Member] | Sabine Mining Co [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		231,155			231,155			228,349
Southwestern Electric Power Co [Member] | Equity [Member] | Sabine Mining Co [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		297			297			415
Southwestern Electric Power Co [Member] | Total Liabilities And Equity [Member] | Sabine Mining Co [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		$ 259,574			$ 259,574			265,050
AEP Generating Co [Member] | Rockport Generating Plant (Unit No. 1) [Member]
Variable Interest Entities (Textuals) [Abstract]
Jointly Owned Utility Plant, Proportionate Ownership Share		50.00%			50.00%
AEP Generating Co [Member] | Rockport Generating Plant (Unit No. 2) [Member]
Variable Interest Entities (Textuals) [Abstract]
Percentage Interest in Rockport Plant Unit 2 Lease		50.00%			50.00%
AEP Generating Co [Member] | Lawrenceburg Generating Station [Member]
Variable Interest Entities (Textuals) [Abstract]
Jointly Owned Utility Plant, Proportionate Ownership Share		100.00%			100.00%
Cleco Power, LLC [Member]
Variable Interest Entities (Textuals) [Abstract]
Percentage of VIE Sales of Lignite Produced					50.00%
First Energy Corp [Member] | Allegheny Series [Member]
Variable Interest Entities (Textuals) [Abstract]
Percentage Ownership of "Allegheny Series" by a Nonaffiliated Company					100.00%
Ohio Power Co [Member]
Related Party Transaction, Due from (to) Related Party, Current		$ 187,812			$ 187,812
Variable Interest Entities (Textuals) [Abstract]
Securitized Transition Assets		97,849			97,849			109,999
Ohio Power Co [Member] | Billings from American Electric Power Service Corporation [Member]
Billings from Affiliates
Billings from VIE		40,907		40,441	80,137		79,490
Variable Interest Entities (Textuals) [Abstract]
Billings from VIE		40,907		$ 40,441	80,137		$ 79,490
Ohio Power Co [Member] | Carrying Amount in AEPSC's Accounts Payable [Member]
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures [Abstract]
As Reported on the Consolidated Balance Sheet		15,423			15,423			24,695
Maximum Exposure		15,423			15,423			24,695
Ohio Power Co [Member] | Ohio Phase-In-Recovery Funding [Member]
Variable Interest Entities (Textuals) [Abstract]
Securitization Bonds		210,000			210,000			232,000
Securitized Transition Assets		98,000			98,000			110,000
Ohio Power Co [Member] | Current Assets [Member] | Ohio Phase-In-Recovery Funding [Member]
ASSETS
Assets		32,778			32,778			32,676
Ohio Power Co [Member] | Other Non Current Assets [Member] | Ohio Phase-In-Recovery Funding [Member]
ASSETS
Assets	[5]	186,609			186,609			209,922
Variable Interest Entities (Textuals) [Abstract]
Intercompany Item Eliminated in Consolidation		87,000			87,000			97,000
Ohio Power Co [Member] | Total Assets [Member] | Ohio Phase-In-Recovery Funding [Member]
ASSETS
Assets		219,387			219,387			242,598
Ohio Power Co [Member] | Current Liabilities [Member] | Ohio Phase-In-Recovery Funding [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		47,539			47,539			47,099
Ohio Power Co [Member] | Noncurrent Liabilities [Member] | Ohio Phase-In-Recovery Funding [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		170,511			170,511			194,162
Ohio Power Co [Member] | Equity [Member] | Ohio Phase-In-Recovery Funding [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		1,337			1,337			1,337
Ohio Power Co [Member] | Total Liabilities And Equity [Member] | Ohio Phase-In-Recovery Funding [Member]
LIABILITIES AND EQUITY
Liabilities and Equity		$ 219,387			$ 219,387			$ 242,598

[1] (a)Includes an intercompany item eliminated in consolidation of $72 million

[2] (a)Includes an intercompany item eliminated in consolidation of $75 million

[3] (a)Includes an intercompany item eliminated in consolidation as of June 30, 2015 and December 31, 2014 of $4 million and $4 million, respectively.

[4] (a)Includes affiliate advances due to Parent related to participation in the Utility Money Pool of $56 million and $56 million in 2015 and 2014, respectively.

[5] (a)Includes an intercompany item eliminated in consolidation as of June 30, 2015 and December 31, 2014 of $87 million and $97 million, respectively.