Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	$ 18,000	$ 19,000	$ 35,000	$ 38,000
Interest Cost	51,000	55,000	101,000	111,000
Expected Return on Plan Assets	(70,000)	(79,000)	(139,000)	(159,000)
Amortization of Prior Service Cost (Credit)	0	0	1,000	0
Amortization of Net Actuarial Loss	46,000	38,000	92,000	75,000
Net Periodic Benefit Cost (Credit)	45,000	33,000	90,000	65,000
Pension Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,542	1,891	3,085	3,782
Interest Cost	6,915	7,553	13,831	15,106
Expected Return on Plan Assets	(9,260)	(10,486)	(18,520)	(20,972)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	50	119	99	238
Amortization of Net Actuarial Loss	6,257	5,084	12,513	10,169
Net Periodic Benefit Cost (Credit)	5,504	4,161	11,008	8,323
Pension Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,184	2,477	4,368	4,954
Interest Cost	6,025	6,561	12,050	13,122
Expected Return on Plan Assets	(8,206)	(9,392)	(16,413)	(18,783)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	48	102	97	204
Amortization of Net Actuarial Loss	5,422	4,393	10,844	8,785
Net Periodic Benefit Cost (Credit)	5,473	4,141	10,946	8,282
Pension Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,373	2,751	4,745	5,502
Interest Cost	10,292	11,299	20,584	22,597
Expected Return on Plan Assets	(15,142)	(17,101)	(30,283)	(34,201)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	70	185	141	371
Amortization of Net Actuarial Loss	9,309	7,610	18,618	15,220
Net Periodic Benefit Cost (Credit)	6,902	4,744	13,805	9,489
Pension Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,390	1,488	2,781	2,976
Interest Cost	2,749	3,075	5,497	6,150
Expected Return on Plan Assets	(3,919)	(4,504)	(7,837)	(9,008)
Amortization of Prior Service Cost (Credit)	74	(237)	148	(474)
Amortization of Net Actuarial Loss	2,461	2,051	4,922	4,103
Net Periodic Benefit Cost (Credit)	2,755	1,873	5,511	3,747
Pension Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,753	1,774	3,506	3,549
Interest Cost	2,863	3,135	5,727	6,269
Expected Return on Plan Assets	(4,128)	(4,716)	(8,255)	(9,433)
Amortization of Prior Service Cost (Credit)	88	(199)	175	(397)
Amortization of Net Actuarial Loss	2,554	2,082	5,107	4,165
Net Periodic Benefit Cost (Credit)	3,130	2,076	6,260	4,153
Other Postretirement Benefit Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	6,000	11,000	12,000	23,000
Interest Cost	17,000	26,000	35,000	52,000
Expected Return on Plan Assets	(26,000)	(25,000)	(53,000)	(50,000)
Amortization of Prior Service Cost (Credit)	(18,000)	(4,000)	(35,000)	(9,000)
Amortization of Net Actuarial Loss	16,000	15,000	32,000	29,000
Net Periodic Benefit Cost (Credit)	(5,000)	23,000	(9,000)	45,000
Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	642	1,347	1,283	2,694
Interest Cost	3,364	4,615	6,727	9,231
Expected Return on Plan Assets	(4,537)	(4,188)	(9,073)	(8,376)
Amortization of Transition Obligation	0	200	0	400
Amortization of Prior Service Cost (Credit)	(2,513)	(715)	(5,025)	(1,431)
Amortization of Net Actuarial Loss	3,062	2,632	6,124	5,263
Net Periodic Benefit Cost (Credit)	18	3,891	36	7,781
Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	805	1,655	1,610	3,310
Interest Cost	2,055	3,197	4,110	6,393
Expected Return on Plan Assets	(3,296)	(3,212)	(6,592)	(6,423)
Amortization of Transition Obligation	0	33	0	66
Amortization of Prior Service Cost (Credit)	(2,355)	(596)	(4,710)	(1,192)
Amortization of Net Actuarial Loss	1,881	1,763	3,763	3,525
Net Periodic Benefit Cost (Credit)	(910)	2,840	(1,819)	5,679
Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,299	2,187	2,599	4,374
Interest Cost	4,447	6,048	8,894	12,095
Expected Return on Plan Assets	(6,239)	(5,639)	(12,477)	(11,278)
Amortization of Transition Obligation	0	26	0	52
Amortization of Prior Service Cost (Credit)	(3,230)	(968)	(6,461)	(1,936)
Amortization of Net Actuarial Loss	4,041	3,417	8,082	6,834
Net Periodic Benefit Cost (Credit)	318	5,071	637	10,141
Other Postretirement Benefit Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	343	709	686	1,418
Interest Cost	948	1,450	1,896	2,899
Expected Return on Plan Assets	(1,522)	(1,481)	(3,044)	(2,961)
Amortization of Prior Service Cost (Credit)	(1,073)	(269)	(2,145)	(539)
Amortization of Net Actuarial Loss	869	797	1,738	1,594
Net Periodic Benefit Cost (Credit)	(435)	1,206	(869)	2,411
Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	423	831	846	1,662
Interest Cost	1,076	1,668	2,151	3,336
Expected Return on Plan Assets	(1,720)	(1,698)	(3,440)	(3,397)
Amortization of Prior Service Cost (Credit)	(1,290)	(233)	(2,578)	(466)
Amortization of Net Actuarial Loss	982	914	1,964	1,829
Net Periodic Benefit Cost (Credit)	$ (529)	$ 1,482	$ (1,057)	$ 2,964