Fair Value Long-term Debt, Other Temporary Investments, Nuclear Trusts (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011	Dec. 31, 2011
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	$ 17,227,000,000			$ 17,227,000,000			$ 16,516,000,000
Long Term Debt, Fair Value	20,457,000,000			20,457,000,000			19,259,000,000
Other Temporary Investments
Cost	272,000,000			272,000,000			291,000,000
Gross Unrealized Gains	6,000,000			6,000,000			3,000,000
Gross Unrealized Losses	0			0			0
Estimated Fair Value	278,000,000			278,000,000			294,000,000
Debt and Equity Securities Within Other Temporary Investments [Abstract]
Proceeds from Investment Sales	0		21,000,000	0		268,000,000
Purchases of Investments	0		0	1,000,000		153,000,000
Gross Realized Gains on Investment Sales	0		4,000,000	0		4,000,000
Gross Realized Losses on Investment Sales	0		0	0		0
Accumulated Other Comprehesive Income Loss Activity for Other Temporary Investments
Balance in AOCI	3,000,000			2,000,000
Change in Fair Value Recognized in AOCI	1,000,000			2,000,000
Amount of (Gain) or Loss Reclassified from AOCI to Statement of Income: Interest Income	0			0
Balance in AOCI	4,000,000			4,000,000
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	1,700,000,000			1,700,000,000			1,592,000,000
Gross Unrealized Gains	406,000,000			406,000,000			281,000,000
Other-Than-Temporary Impairments	(81,000,000)			(81,000,000)			(85,000,000)
Securities Activity Within Decommissioning and SNF Trusts [Abstract]
Proceeds from Investment Sales	182,000,000		361,000,000	699,000,000		826,000,000
Purchases of Investments	199,000,000		379,000,000	744,000,000		871,000,000
Gross Realized Gains on Investment Sales	2,000,000		18,000,000	7,000,000		30,000,000
Gross Realized Losses on Investment Sales	1,000,000		12,000,000	3,000,000		21,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	1,700,000,000			1,700,000,000			1,592,000,000
Fair Value Measurements (Textuals) [Abstract]
Adjusted Cost of Debt Securities	840,000,000			840,000,000			862,000,000
Adjusted Cost of Domestic Equity Securities	441,000,000			441,000,000			431,000,000
Appalachian Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	3,702,283,000			3,702,283,000			3,726,251,000
Long Term Debt, Fair Value	4,597,740,000			4,597,740,000			4,431,912,000
Indiana Michigan Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	2,109,630,000			2,109,630,000			2,057,675,000
Long Term Debt, Fair Value	2,431,912,000			2,431,912,000			2,339,344,000
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	1,699,691,000			1,699,691,000			1,591,732,000
Gross Unrealized Gains	405,777,000			405,777,000			280,196,000
Other-Than-Temporary Impairments	(80,369,000)			(80,369,000)			(83,855,000)
Securities Activity Within Decommissioning and SNF Trusts [Abstract]
Proceeds from Investment Sales	181,988,000		361,001,000	698,567,000		825,689,000
Purchases of Investments	199,150,000		378,607,000	744,131,000		870,769,000
Gross Realized Gains on Investment Sales	2,046,000		17,256,000	6,978,000		29,661,000
Gross Realized Losses on Investment Sales	924,000		11,313,000	3,143,000		20,603,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	1,699,691,000			1,699,691,000			1,591,732,000
Fair Value Measurements (Textuals) [Abstract]
Adjusted Cost of Debt Securities	840,000,000			840,000,000			862,000,000
Adjusted Cost of Domestic Equity Securities	441,000,000			441,000,000			431,000,000
Ohio Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	3,860,242,000			3,860,242,000			4,054,148,000
Long Term Debt, Fair Value	4,589,998,000			4,589,998,000			4,665,739,000
Public Service Co Of Oklahoma [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	949,884,000			949,884,000			947,364,000
Long Term Debt, Fair Value	1,187,155,000			1,187,155,000			1,123,306,000
Southwestern Electric Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	2,046,139,000			2,046,139,000			1,728,637,000
Long Term Debt, Fair Value	2,424,311,000			2,424,311,000			2,019,094,000
Cash [Member]
Other Temporary Investments
Cost	197,000,000			197,000,000			216,000,000
Gross Unrealized Gains	0			0			0
Gross Unrealized Losses	0			0			0
Estimated Fair Value	197,000,000	[1],[2]		197,000,000	[1],[2]		216,000,000	[1]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	13,000,000	[2]		13,000,000	[2]		18,000,000	[2]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	13,000,000	[2]		13,000,000	[2]		18,000,000	[2]
Cash [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	12,945,000	[2]		12,945,000	[2]		18,229,000	[2]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	12,945,000	[2]		12,945,000	[2]		18,229,000	[2]
Fixed Income Funds [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	955,000,000			955,000,000			928,000,000
Gross Unrealized Gains	115,000,000			115,000,000			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	955,000,000			955,000,000			928,000,000
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	955,067,000			955,067,000			927,471,000
Gross Unrealized Gains	114,553,000			114,553,000			65,448,000
Other-Than-Temporary Impairments	(2,707,000)			(2,707,000)			(4,319,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	955,067,000			955,067,000			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
Estimated Fair Value	0			0			0
Domestic [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	732,000,000	[3]		732,000,000	[3]		646,000,000	[3]
Gross Unrealized Gains	291,000,000			291,000,000			215,000,000
Other-Than-Temporary Impairments	(78,000,000)			(78,000,000)			(80,000,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	732,000,000	[3]		732,000,000	[3]		646,000,000	[3]
Domestic [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	731,679,000	[3]		731,679,000	[3]		646,032,000	[3]
Gross Unrealized Gains	291,224,000			291,224,000			214,748,000
Other-Than-Temporary Impairments	(77,662,000)			(77,662,000)			(79,536,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	731,679,000	[3]		731,679,000	[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	5,000,000			5,000,000			3,000,000
Gross Unrealized Losses	0			0			0
Estimated Fair Value	16,000,000	[3]		16,000,000	[3]		14,000,000	[3]
Cash and Cash Equivalents [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	13,000,000			13,000,000			18,000,000
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	13,000,000			13,000,000			18,000,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	12,945,000			12,945,000			18,229,000
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	12,945,000			12,945,000			18,229,000
US Government Agencies Debt Securities [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	693,000,000			693,000,000			544,000,000
Gross Unrealized Gains	108,000,000			108,000,000			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	693,000,000			693,000,000			544,000,000
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	693,127,000			693,127,000			543,506,000
Gross Unrealized Gains	107,721,000			107,721,000			60,946,000
Other-Than-Temporary Impairments	(612,000)			(612,000)			(547,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	693,127,000			693,127,000			543,506,000
Corporate Debt [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	36,000,000			36,000,000			54,000,000
Gross Unrealized Gains	6,000,000			6,000,000			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	36,000,000			36,000,000			54,000,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	35,798,000			35,798,000			53,979,000
Gross Unrealized Gains	5,531,000			5,531,000			4,932,000
Other-Than-Temporary Impairments	(1,435,000)			(1,435,000)			(1,536,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	35,798,000			35,798,000			53,979,000
State and Local Jurisdiction [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	226,000,000			226,000,000			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	226,000,000			226,000,000			330,000,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	226,142,000			226,142,000			329,986,000
Gross Unrealized Gains	1,301,000			1,301,000			(430,000)
Other-Than-Temporary Impairments	(660,000)			(660,000)			(2,236,000)
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	226,142,000			226,142,000			329,986,000
Within One Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	136,000,000			136,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	136,000,000			136,000,000
Within One Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	136,610,000			136,610,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	136,610,000			136,610,000
One Year To Five Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	357,000,000			357,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	357,000,000			357,000,000
One Year To Five Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	356,630,000			356,630,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	356,630,000			356,630,000
Five Year To Ten Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	265,000,000			265,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	265,000,000			265,000,000
Five Year To Ten Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	265,125,000			265,125,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	265,125,000			265,125,000
After Ten Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	197,000,000			197,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	197,000,000			197,000,000
After Ten Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	196,702,000			196,702,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	$ 196,702,000			$ 196,702,000

[1] 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.

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

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