Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pension Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	$ 19,000	$ 18,000	$ 57,000	$ 54,000
Interest Cost	56,000	59,000	167,000	178,000
Expected Return on Plan Assets	(80,000)	(79,000)	(239,000)	(236,000)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	0	1,000	0	1,000
Amortization of Net Actuarial Loss	42,000	31,000	117,000	92,000
Net Periodic Benefit Cost	37,000	30,000	102,000	89,000
Pension Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,892	1,799	5,674	5,399
Interest Cost	7,553	8,073	22,659	24,219
Expected Return on Plan Assets	(10,486)	(10,458)	(31,458)	(31,374)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	118	230	356	688
Amortization of Net Actuarial Loss	5,085	4,142	15,254	12,427
Net Periodic Benefit Cost	4,162	3,786	12,485	11,359
Pension Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,477	2,362	7,431	7,085
Interest Cost	6,562	6,931	19,684	20,794
Expected Return on Plan Assets	(9,392)	(9,213)	(28,175)	(27,641)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	101	186	305	558
Amortization of Net Actuarial Loss	4,392	3,536	13,177	10,608
Net Periodic Benefit Cost	4,140	3,802	12,422	11,404
Pension Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,751	2,557	8,253	7,672
Interest Cost	11,298	12,087	33,895	36,263
Expected Return on Plan Assets	(17,100)	(16,364)	(51,301)	(49,097)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	186	368	557	1,104
Amortization of Net Actuarial Loss	7,610	6,207	22,830	18,621
Net Periodic Benefit Cost	4,745	4,855	14,234	14,563
Pension Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,487	1,440	4,463	4,320
Interest Cost	3,076	3,321	9,226	9,964
Expected Return on Plan Assets	(4,503)	(4,366)	(13,511)	(13,098)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	(237)	(238)	(711)	(713)
Amortization of Net Actuarial Loss	2,051	1,690	6,154	5,068
Net Periodic Benefit Cost	1,874	1,847	5,621	5,541
Pension Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,775	1,644	5,324	4,930
Interest Cost	3,134	3,333	9,403	9,999
Expected Return on Plan Assets	(4,717)	(4,596)	(14,150)	(13,786)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	(198)	(199)	(595)	(597)
Amortization of Net Actuarial Loss	2,083	1,690	6,248	5,070
Net Periodic Benefit Cost	2,077	1,872	6,230	5,616
Other Postretirement Benefit Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	12,000	11,000	35,000	32,000
Interest Cost	26,000	27,000	78,000	81,000
Expected Return on Plan Assets	(26,000)	(27,000)	(76,000)	(81,000)
Amortization of Transition Obligation	1,000	1,000	1,000	1,000
Amortization of Prior Service Cost (Credit)	(5,000)	(1,000)	(14,000)	(1,000)
Amortization of Net Actuarial Loss	14,000	8,000	43,000	23,000
Net Periodic Benefit Cost	22,000	19,000	67,000	55,000
Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,346	1,245	4,040	3,737
Interest Cost	4,616	4,867	13,847	14,601
Expected Return on Plan Assets	(4,188)	(4,496)	(12,564)	(13,488)
Amortization of Transition Obligation	201	286	601	859
Amortization of Prior Service Cost (Credit)	(716)	(42)	(2,147)	(128)
Amortization of Net Actuarial Loss	2,631	1,465	7,894	4,379
Net Periodic Benefit Cost	3,890	3,325	11,671	9,960
Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,655	1,531	4,965	4,590
Interest Cost	3,196	3,402	9,589	10,207
Expected Return on Plan Assets	(3,212)	(3,471)	(9,635)	(10,414)
Amortization of Transition Obligation	33	47	99	141
Amortization of Prior Service Cost (Credit)	(595)	(59)	(1,787)	(177)
Amortization of Net Actuarial Loss	1,762	891	5,287	2,674
Net Periodic Benefit Cost	2,839	2,341	8,518	7,021
Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,187	1,957	6,561	5,870
Interest Cost	6,047	6,375	18,142	19,123
Expected Return on Plan Assets	(5,639)	(6,129)	(16,917)	(18,385)
Amortization of Transition Obligation	26	37	78	112
Amortization of Prior Service Cost (Credit)	(969)	(53)	(2,905)	(160)
Amortization of Net Actuarial Loss	3,418	2,265	10,252	5,914
Net Periodic Benefit Cost	5,070	4,452	15,211	12,474
Other Postretirement Benefit Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	709	655	2,127	1,966
Interest Cost	1,449	1,512	4,348	4,535
Expected Return on Plan Assets	(1,480)	(1,566)	(4,441)	(4,698)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	(270)	(19)	(809)	(57)
Amortization of Net Actuarial Loss	797	389	2,391	1,165
Net Periodic Benefit Cost	1,205	971	3,616	2,911
Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	831	757	2,493	2,271
Interest Cost	1,669	1,742	5,005	5,227
Expected Return on Plan Assets	(1,699)	(1,800)	(5,096)	(5,400)
Amortization of Transition Obligation	0	0	0	0
Amortization of Prior Service Cost (Credit)	(234)	64	(700)	193
Amortization of Net Actuarial Loss	915	447	2,744	1,339
Net Periodic Benefit Cost	$ 1,482	$ 1,210	$ 4,446	$ 3,630