Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Pension Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	$ 18,000	$ 18,000	$ 36,000	$ 35,000
Interest Cost	56,000	51,000	111,000	101,000
Expected Return on Plan Assets	(65,000)	(70,000)	(131,000)	(139,000)
Amortization of Prior Service Cost (Credit)	0	0	1,000	1,000
Amortization of Net Actuarial Loss	31,000	46,000	62,000	92,000
Net Periodic Benefit Cost (Credit)	40,000	45,000	79,000	90,000
Pension Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,759	1,542	3,518	3,085
Interest Cost	7,406	6,915	14,812	13,831
Expected Return on Plan Assets	(8,481)	(9,260)	(16,963)	(18,520)
Amortization of Prior Service Cost (Credit)	49	50	99	99
Amortization of Net Actuarial Loss	4,148	6,257	8,296	12,513
Net Periodic Benefit Cost (Credit)	4,881	5,504	9,762	11,008
Pension Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	2,517	2,184	5,034	4,368
Interest Cost	6,574	6,025	13,147	12,050
Expected Return on Plan Assets	(7,748)	(8,206)	(15,496)	(16,413)
Amortization of Prior Service Cost (Credit)	48	48	97	97
Amortization of Net Actuarial Loss	3,646	5,422	7,292	10,844
Net Periodic Benefit Cost (Credit)	5,037	5,473	10,074	10,946
Pension Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,285	2,373	2,570	4,745
Interest Cost	5,526	10,292	11,052	20,584
Expected Return on Plan Assets	(6,606)	(15,142)	(13,213)	(30,283)
Amortization of Prior Service Cost (Credit)	39	70	78	141
Amortization of Net Actuarial Loss	3,105	9,309	6,211	18,618
Net Periodic Benefit Cost (Credit)	3,349	6,902	6,698	13,805
Pension Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,302	1,390	2,604	2,781
Interest Cost	3,014	2,749	6,028	5,497
Expected Return on Plan Assets	(3,651)	(3,919)	(7,302)	(7,837)
Amortization of Prior Service Cost (Credit)	74	74	148	148
Amortization of Net Actuarial Loss	1,688	2,461	3,376	4,922
Net Periodic Benefit Cost (Credit)	2,427	2,755	4,854	5,511
Pension Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	1,654	1,753	3,309	3,506
Interest Cost	3,162	2,863	6,325	5,727
Expected Return on Plan Assets	(3,857)	(4,128)	(7,714)	(8,255)
Amortization of Prior Service Cost (Credit)	88	88	175	175
Amortization of Net Actuarial Loss	1,762	2,554	3,523	5,107
Net Periodic Benefit Cost (Credit)	2,809	3,130	5,618	6,260
Other Postretirement Benefit Plans [Member]
Components of Net Periodic Benefit Cost
Service Cost	3,000	6,000	7,000	12,000
Interest Cost	17,000	17,000	34,000	35,000
Expected Return on Plan Assets	(28,000)	(26,000)	(56,000)	(53,000)
Amortization of Prior Service Cost (Credit)	(17,000)	(18,000)	(34,000)	(35,000)
Amortization of Net Actuarial Loss	6,000	16,000	11,000	32,000
Net Periodic Benefit Cost (Credit)	(19,000)	(5,000)	(38,000)	(9,000)
Other Postretirement Benefit Plans [Member] | Appalachian Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	362	642	724	1,283
Interest Cost	3,197	3,364	6,394	6,727
Expected Return on Plan Assets	(4,633)	(4,537)	(9,266)	(9,073)
Amortization of Prior Service Cost (Credit)	(2,512)	(2,513)	(5,025)	(5,025)
Amortization of Net Actuarial Loss	1,145	3,062	2,291	6,124
Net Periodic Benefit Cost (Credit)	(2,441)	18	(4,882)	36
Other Postretirement Benefit Plans [Member] | Indiana Michigan Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	487	805	974	1,610
Interest Cost	1,910	2,055	3,819	4,110
Expected Return on Plan Assets	(3,363)	(3,296)	(6,727)	(6,592)
Amortization of Prior Service Cost (Credit)	(2,356)	(2,355)	(4,711)	(4,710)
Amortization of Net Actuarial Loss	592	1,881	1,184	3,763
Net Periodic Benefit Cost (Credit)	(2,730)	(910)	(5,461)	(1,819)
Other Postretirement Benefit Plans [Member] | Ohio Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	257	1,299	513	2,599
Interest Cost	1,900	4,447	3,801	8,894
Expected Return on Plan Assets	(3,380)	(6,239)	(6,760)	(12,477)
Amortization of Prior Service Cost (Credit)	(1,730)	(3,230)	(3,461)	(6,461)
Amortization of Net Actuarial Loss	595	4,041	1,190	8,082
Net Periodic Benefit Cost (Credit)	(2,358)	318	(4,717)	637
Other Postretirement Benefit Plans [Member] | Public Service Co Of Oklahoma [Member]
Components of Net Periodic Benefit Cost
Service Cost	210	343	420	686
Interest Cost	894	948	1,787	1,896
Expected Return on Plan Assets	(1,575)	(1,522)	(3,150)	(3,044)
Amortization of Prior Service Cost (Credit)	(1,073)	(1,073)	(2,145)	(2,145)
Amortization of Net Actuarial Loss	277	869	554	1,738
Net Periodic Benefit Cost (Credit)	(1,267)	(435)	(2,534)	(869)
Other Postretirement Benefit Plans [Member] | Southwestern Electric Power Co [Member]
Components of Net Periodic Benefit Cost
Service Cost	253	423	506	846
Interest Cost	998	1,076	1,996	2,151
Expected Return on Plan Assets	(1,754)	(1,720)	(3,508)	(3,440)
Amortization of Prior Service Cost (Credit)	(1,289)	(1,290)	(2,578)	(2,578)
Amortization of Net Actuarial Loss	308	982	617	1,964
Net Periodic Benefit Cost (Credit)	$ (1,484)	$ (529)	$ (2,967)	$ (1,057)