Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	$ 18,000	$ 17,000	$ 54,000	$ 52,000
Interest Cost	55,000	51,000	166,000	152,000
Expected Return on Plan Assets	(65,000)	(69,000)	(196,000)	(208,000)
Amortization of Prior Service Cost (Credit)	1,000	1,000	2,000	2,000
Amortization of Net Actuarial Loss	31,000	45,000	93,000	137,000
Net Periodic Benefit Cost (Credit)	40,000	45,000	119,000	135,000
Pension Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,759	1,543	5,277	4,628
Interest Cost	7,406	6,916	22,218	20,747
Expected Return on Plan Assets	(8,482)	(9,260)	(25,445)	(27,780)
Amortization of Prior Service Cost (Credit)	49	49	148	148
Amortization of Net Actuarial Loss	4,149	6,256	12,445	18,769
Net Periodic Benefit Cost (Credit)	4,881	5,504	14,643	16,512
Pension Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,517	2,183	7,551	6,551
Interest Cost	6,573	6,025	19,720	18,075
Expected Return on Plan Assets	(7,749)	(8,206)	(23,245)	(24,619)
Amortization of Prior Service Cost (Credit)	49	49	146	146
Amortization of Net Actuarial Loss	3,647	5,422	10,939	16,266
Net Periodic Benefit Cost (Credit)	5,037	5,473	15,111	16,419
Pension Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,285	2,362	3,855	7,107
Interest Cost	5,527	10,268	16,579	30,852
Expected Return on Plan Assets	(6,607)	(15,103)	(19,820)	(45,386)
Amortization of Prior Service Cost (Credit)	40	71	118	212
Amortization of Net Actuarial Loss	3,105	9,287	9,316	27,905
Net Periodic Benefit Cost (Credit)	3,350	6,885	10,048	20,690
Pension Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,301	1,391	3,905	4,172
Interest Cost	3,015	2,748	9,043	8,245
Expected Return on Plan Assets	(3,651)	(3,919)	(10,953)	(11,756)
Amortization of Prior Service Cost (Credit)	74	75	222	223
Amortization of Net Actuarial Loss	1,689	2,461	5,065	7,383
Net Periodic Benefit Cost (Credit)	2,428	2,756	7,282	8,267
Pension Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,655	1,752	4,964	5,258
Interest Cost	3,163	2,864	9,488	8,591
Expected Return on Plan Assets	(3,857)	(4,126)	(11,571)	(12,381)
Amortization of Prior Service Cost (Credit)	87	87	262	262
Amortization of Net Actuarial Loss	1,762	2,553	5,285	7,660
Net Periodic Benefit Cost (Credit)	2,810	3,130	8,428	9,390
Other Postretirement Benefit Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	4,000	5,000	11,000	17,000
Interest Cost	16,000	18,000	50,000	53,000
Expected Return on Plan Assets	(28,000)	(27,000)	(84,000)	(80,000)
Amortization of Prior Service Cost (Credit)	(18,000)	(17,000)	(52,000)	(52,000)
Amortization of Net Actuarial Loss	6,000	16,000	17,000	48,000
Net Periodic Benefit Cost (Credit)	(20,000)	(5,000)	(58,000)	(14,000)
Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	362	641	1,086	1,924
Interest Cost	3,197	3,363	9,591	10,090
Expected Return on Plan Assets	(4,634)	(4,537)	(13,900)	(13,610)
Amortization of Prior Service Cost (Credit)	(2,512)	(2,512)	(7,537)	(7,537)
Amortization of Net Actuarial Loss	1,145	3,063	3,436	9,187
Net Periodic Benefit Cost (Credit)	(2,442)	18	(7,324)	54
Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	486	804	1,460	2,414
Interest Cost	1,909	2,056	5,728	6,166
Expected Return on Plan Assets	(3,363)	(3,295)	(10,090)	(9,887)
Amortization of Prior Service Cost (Credit)	(2,355)	(2,356)	(7,066)	(7,066)
Amortization of Net Actuarial Loss	592	1,882	1,776	5,645
Net Periodic Benefit Cost (Credit)	(2,731)	(909)	(8,192)	(2,728)
Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	256	1,028	769	3,627
Interest Cost	1,900	4,100	5,701	12,994
Expected Return on Plan Assets	(3,379)	(6,221)	(10,139)	(18,698)
Amortization of Prior Service Cost (Credit)	(1,731)	(3,219)	(5,192)	(9,680)
Amortization of Net Actuarial Loss	595	3,761	1,785	11,843
Net Periodic Benefit Cost (Credit)	(2,359)	(551)	(7,076)	86
Other Postretirement Benefit Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	209	343	629	1,029
Interest Cost	893	948	2,680	2,844
Expected Return on Plan Assets	(1,575)	(1,522)	(4,725)	(4,566)
Amortization of Prior Service Cost (Credit)	(1,072)	(1,072)	(3,217)	(3,217)
Amortization of Net Actuarial Loss	278	869	832	2,607
Net Periodic Benefit Cost (Credit)	(1,267)	(434)	(3,801)	(1,303)
Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	253	424	759	1,270
Interest Cost	998	1,075	2,994	3,226
Expected Return on Plan Assets	(1,754)	(1,720)	(5,262)	(5,160)
Amortization of Prior Service Cost (Credit)	(1,289)	(1,289)	(3,867)	(3,867)
Amortization of Net Actuarial Loss	309	982	926	2,946
Net Periodic Benefit Cost (Credit)	$ (1,483)	$ (528)	$ (4,450)	$ (1,585)