Fair Value Long-term Debt, Other Temporary Investments, Nuclear Trusts (Details) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011	Jun. 30, 2012		Jun. 30, 2011	Dec. 31, 2011
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	$ 17,302,000,000			$ 17,302,000,000			$ 16,516,000,000
Long Term Debt, Fair Value	20,025,000,000			20,025,000,000			19,259,000,000
Other Temporary Investments
Estimated Fair Value	297,000,000			297,000,000			294,000,000
Debt and Equity Securities Within Other Temporary Investments [Abstract]
Proceeds from Investment Sales	0		51,000,000	0		247,000,000
Purchases of Investments	1,000,000		5,000,000	1,000,000		153,000,000
Gross Realized Gains on Investment Sales	0		0	0		0
Gross Realized Losses on Investment Sales	0		0	0		0
Accumulated Other Comprehesive Income Loss Activity for Other Temporary Investments
Balance in AOCI	4,000,000			2,000,000
Change in Fair Value Recognized in AOCI	(1,000,000)			1,000,000
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income: Interest Income	0			0
Balance in AOCI	3,000,000			3,000,000
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	1,658,000,000			1,658,000,000			1,592,000,000
Gross Unrealized Gains	368,000,000			368,000,000			281,000,000
Other-Than-Temporary Impairments	(82,000,000)			(82,000,000)			(85,000,000)
Securities Activity Within Decommissioning and SNF Trusts [Abstract]
Proceeds from Investment Sales	183,000,000		177,000,000	517,000,000		465,000,000
Purchases of Investments	192,000,000		186,000,000	545,000,000		492,000,000
Gross Realized Gains on Investment Sales	3,000,000		7,000,000	5,000,000		12,000,000
Gross Realized Losses on Investment Sales	1,000,000		4,000,000	2,000,000		9,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	1,658,000,000			1,658,000,000			1,592,000,000
Fair Value Measurements (Textuals) [Abstract]
Adjusted Cost of Debt Securities	834,000,000			834,000,000			862,000,000
Adjusted Cost of Domestic Equity Securities	440,000,000			440,000,000			431,000,000
Appalachian Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	3,677,116,000			3,677,116,000			3,726,251,000
Long Term Debt, Fair Value	4,380,840,000			4,380,840,000			4,431,912,000
Indiana Michigan Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	2,131,501,000			2,131,501,000			2,057,675,000
Long Term Debt, Fair Value	2,402,581,000			2,402,581,000			2,339,344,000
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	1,657,502,000			1,657,502,000			1,591,732,000
Gross Unrealized Gains	368,180,000			368,180,000			280,196,000
Other-Than-Temporary Impairments	(82,126,000)			(82,126,000)			(83,855,000)
Securities Activity Within Decommissioning and SNF Trusts [Abstract]
Proceeds from Investment Sales	182,179,000		176,927,000	516,579,000		464,688,000
Purchases of Investments	192,104,000		186,217,000	544,981,000		492,162,000
Gross Realized Gains on Investment Sales	3,380,000		7,392,000	4,932,000		12,405,000
Gross Realized Losses on Investment Sales	803,000		4,043,000	2,219,000		9,290,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	1,657,502,000			1,657,502,000			1,591,732,000
Fair Value Measurements (Textuals) [Abstract]
Adjusted Cost of Debt Securities	834,000,000			834,000,000			862,000,000
Adjusted Cost of Domestic Equity Securities	440,000,000			440,000,000			431,000,000
Ohio Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	3,860,044,000			3,860,044,000			4,054,148,000
Long Term Debt, Fair Value	4,453,479,000			4,453,479,000			4,665,739,000
Public Service Co Of Oklahoma [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	949,897,000			949,897,000			947,364,000
Long Term Debt, Fair Value	1,138,292,000			1,138,292,000			1,123,306,000
Southwestern Electric Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	2,047,676,000			2,047,676,000			1,728,637,000
Long Term Debt, Fair Value	2,315,719,000			2,315,719,000			2,019,094,000
Cash [Member]
Other Temporary Investments
Cost	217,000,000	[1]		217,000,000	[1]		216,000,000	[1]
Gross Unrealized Gains	0			0			0
Gross Unrealized Losses	0			0			0
Estimated Fair Value	217,000,000	[2]		217,000,000	[2]		216,000,000	[2]
Fixed Income Funds [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	944,000,000			944,000,000			928,000,000
Gross Unrealized Gains	110,000,000			110,000,000			66,000,000
Other-Than-Temporary Impairments	(3,000,000)			(3,000,000)			(5,000,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	944,000,000			944,000,000			928,000,000
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	944,269,000			944,269,000			927,471,000
Gross Unrealized Gains	110,205,000			110,205,000			65,448,000
Other-Than-Temporary Impairments	(3,285,000)			(3,285,000)			(4,319,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	944,269,000			944,269,000			927,471,000
Mutual Funds Fixed Income [Member]
Other Temporary Investments
Cost	64,000,000			64,000,000			64,000,000
Gross Unrealized Gains	1,000,000			1,000,000			0
Gross Unrealized Losses	0			0			0
Estimated Fair Value	65,000,000			65,000,000			64,000,000
Variable Rate Demand Notes [Member]
Other Temporary Investments
Cost	0			0			0
Gross Unrealized Gains	0			0			0
Gross Unrealized Losses	0			0			0
Domestic [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	698,000,000	[3]		698,000,000	[3]		646,000,000	[3]
Gross Unrealized Gains	258,000,000			258,000,000			215,000,000
Other-Than-Temporary Impairments	(79,000,000)			(79,000,000)			(80,000,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	698,000,000	[3]		698,000,000	[3]		646,000,000	[3]
Domestic [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	697,407,000	[3]		697,407,000	[3]		646,032,000	[3]
Gross Unrealized Gains	257,975,000			257,975,000			214,748,000
Other-Than-Temporary Impairments	(78,841,000)			(78,841,000)			(79,536,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	697,407,000	[3]		697,407,000	[3]		646,032,000	[3]
Mutual Funds Equity [Member]
Other Temporary Investments
Cost	11,000,000			11,000,000			11,000,000
Gross Unrealized Gains	4,000,000			4,000,000			3,000,000
Gross Unrealized Losses	0			0			0
Estimated Fair Value	15,000,000	[3]		15,000,000	[3]		14,000,000	[3]
Cash and Cash Equivalents [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	16,000,000	[4]		16,000,000	[4]		18,000,000	[4]
Gross Unrealized Gains	0			0			0
Other-Than-Temporary Impairments	0			0			0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	16,000,000	[4]		16,000,000	[4]		18,000,000	[4]
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	15,826,000	[4]		15,826,000	[4]		18,229,000	[4]
Gross Unrealized Gains	0			0			0
Other-Than-Temporary Impairments	0			0			0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	15,826,000	[4]		15,826,000	[4]		18,229,000	[4]
US Government Agencies Debt Securities [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	644,000,000			644,000,000			544,000,000
Gross Unrealized Gains	104,000,000			104,000,000			61,000,000
Other-Than-Temporary Impairments	(1,000,000)			(1,000,000)			(1,000,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	644,000,000			644,000,000			544,000,000
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	643,542,000			643,542,000			543,506,000
Gross Unrealized Gains	104,394,000			104,394,000			60,946,000
Other-Than-Temporary Impairments	(640,000)			(640,000)			(547,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	643,542,000			643,542,000			543,506,000
Corporate Debt [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	44,000,000			44,000,000			54,000,000
Gross Unrealized Gains	5,000,000			5,000,000			5,000,000
Other-Than-Temporary Impairments	(1,000,000)			(1,000,000)			(2,000,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	44,000,000			44,000,000			54,000,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	44,354,000			44,354,000			53,979,000
Gross Unrealized Gains	5,113,000			5,113,000			4,932,000
Other-Than-Temporary Impairments	(1,463,000)			(1,463,000)			(1,536,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	44,354,000			44,354,000			53,979,000
State and Local Jurisdiction [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	256,000,000			256,000,000			330,000,000
Gross Unrealized Gains	1,000,000			1,000,000			0
Other-Than-Temporary Impairments	(1,000,000)			(1,000,000)			(2,000,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	256,000,000			256,000,000			330,000,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	256,373,000			256,373,000			329,986,000
Gross Unrealized Gains	698,000			698,000			(430,000)
Other-Than-Temporary Impairments	(1,182,000)			(1,182,000)			(2,236,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	256,373,000			256,373,000			329,986,000
Other Temporary Investments [Member]
Other Temporary Investments
Cost	292,000,000			292,000,000			291,000,000
Gross Unrealized Gains	5,000,000			5,000,000			3,000,000
Gross Unrealized Losses	0			0			0
Within 1 Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	40,000,000			40,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	40,000,000			40,000,000
Within 1 Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	39,580,000			39,580,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	39,580,000			39,580,000
1 year - 5 years [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	362,000,000			362,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	362,000,000			362,000,000
1 year - 5 years [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	361,676,000			361,676,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	361,676,000			361,676,000
5 years - 10 years [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	315,000,000			315,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	315,000,000			315,000,000
5 years - 10 years [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	315,547,000			315,547,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	315,547,000			315,547,000
After 10 years [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	227,000,000			227,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	227,000,000			227,000,000
After 10 years [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	227,466,000			227,466,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	$ 227,466,000			$ 227,466,000

[1] Primarily represents amounts held for the repayment of debt.

[2] Amounts in ''Other'' column primarily represent cash deposits in bank accounts with financial institutions or with third parties. Level 1 amounts primarily represent investments in money market funds.

[3] Amounts represent publicly traded equity securities and equity-based mutual funds.

[4] Amounts in ''Other'' column primarily represent accrued interest receivables from financial institutions. Level 2 amounts primarily represent investments in money market funds.