Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	$ 19,000	$ 18,000	$ 38,000	$ 36,000
Interest Cost	55,000	60,000	111,000	119,000
Expected Return on Plan Assets	(79,000)	(78,000)	(159,000)	(157,000)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	0	0	0	0
Amortization of Net Actuarial Loss	38,000	31,000	75,000	61,000
Net Periodic Benefit Cost	33,000	31,000	65,000	59,000
Pension Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,891	1,800	3,782	3,600
Interest Cost	7,553	8,076	15,106	16,146
Expected Return on Plan Assets	(10,486)	(10,458)	(20,972)	(20,916)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	119	229	238	458
Amortization of Net Actuarial Loss	5,084	4,144	10,169	8,285
Net Periodic Benefit Cost	4,161	3,791	8,323	7,573
Pension Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,477	2,365	4,954	4,723
Interest Cost	6,561	6,934	13,122	13,863
Expected Return on Plan Assets	(9,392)	(9,214)	(18,783)	(18,428)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	102	186	204	372
Amortization of Net Actuarial Loss	4,393	3,538	8,785	7,072
Net Periodic Benefit Cost	4,141	3,809	8,282	7,602
Pension Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,751	2,558	5,502	5,115
Interest Cost	11,299	12,098	22,597	24,176
Expected Return on Plan Assets	(17,101)	(16,367)	(34,201)	(32,733)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	185	368	371	736
Amortization of Net Actuarial Loss	7,610	6,214	15,220	12,414
Net Periodic Benefit Cost	4,744	4,871	9,489	9,708
Pension Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,488	1,442	2,976	2,880
Interest Cost	3,075	3,338	6,150	6,643
Expected Return on Plan Assets	(4,504)	(4,366)	(9,008)	(8,732)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	(237)	(239)	(474)	(475)
Amortization of Net Actuarial Loss	2,051	1,700	4,103	3,378
Net Periodic Benefit Cost	1,873	1,875	3,747	3,694
Pension Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,774	1,644	3,549	3,286
Interest Cost	3,135	3,348	6,269	6,666
Expected Return on Plan Assets	(4,716)	(4,595)	(9,433)	(9,190)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	(199)	(200)	(397)	(398)
Amortization of Net Actuarial Loss	2,082	1,700	4,165	3,380
Net Periodic Benefit Cost	2,076	1,897	4,153	3,744
Other Postretirement Benefit Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	11,000	10,000	23,000	21,000
Interest Cost	26,000	27,000	52,000	54,000
Expected Return on Plan Assets	(25,000)	(27,000)	(50,000)	(54,000)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	(4,000)	0	(9,000)	0
Amortization of Net Actuarial Loss	15,000	8,000	29,000	15,000
Net Periodic Benefit Cost	23,000	18,000	45,000	36,000
Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,347	1,246	2,694	2,492
Interest Cost	4,615	4,867	9,231	9,734
Expected Return on Plan Assets	(4,188)	(4,496)	(8,376)	(8,992)
Amortization of Transition Obligation	200	287	400	573
Amortization of Prior Service Cost (Credit)	(715)	(43)	(1,431)	(86)
Amortization of Net Actuarial Loss	2,632	1,459	5,263	2,914
Net Periodic Benefit Cost	3,891	3,320	7,781	6,635
Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,655	1,529	3,310	3,059
Interest Cost	3,197	3,402	6,393	6,805
Expected Return on Plan Assets	(3,212)	(3,471)	(6,423)	(6,943)
Amortization of Transition Obligation	33	47	66	94
Amortization of Prior Service Cost (Credit)	(596)	(59)	(1,192)	(118)
Amortization of Net Actuarial Loss	1,763	892	3,525	1,783
Net Periodic Benefit Cost	2,840	2,340	5,679	4,680
Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,187	1,956	4,374	3,913
Interest Cost	6,048	6,373	12,095	12,748
Expected Return on Plan Assets	(5,639)	(6,127)	(11,278)	(12,256)
Amortization of Transition Obligation	26	38	52	75
Amortization of Prior Service Cost (Credit)	(968)	(54)	(1,936)	(107)
Amortization of Net Actuarial Loss	3,417	1,845	6,834	3,649
Net Periodic Benefit Cost	5,071	4,031	10,141	8,022
Other Postretirement Benefit Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	709	656	1,418	1,311
Interest Cost	1,450	1,511	2,899	3,023
Expected Return on Plan Assets	(1,481)	(1,566)	(2,961)	(3,132)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	(269)	(19)	(539)	(38)
Amortization of Net Actuarial Loss	797	388	1,594	776
Net Periodic Benefit Cost	1,206	970	2,411	1,940
Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	831	757	1,662	1,514
Interest Cost	1,668	1,743	3,336	3,485
Expected Return on Plan Assets	(1,698)	(1,800)	(3,397)	(3,600)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	(233)	64	(466)	129
Amortization of Net Actuarial Loss	914	446	1,829	892
Net Periodic Benefit Cost	$ 1,482	$ 1,210	$ 2,964	$ 2,420