Fair Value Long-term Debt, Other Temporary Investments, Nuclear Trusts (Details) (USD $)	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012	Dec. 31, 2012
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	$ 17,573,000,000			$ 17,757,000,000
Long Term Debt, Fair Value	20,448,000,000			20,907,000,000
Other Temporary Investments
Cost	253,000,000			316,000,000
Gross Unrealized Gains	8,000,000			8,000,000
Gross Unrealized Losses	0			0
Estimated Fair Value	261,000,000			324,000,000
Debt and Equity Securities Within Other Temporary Investments [Abstract]
Proceeds from Investment Sales	0		0
Purchases of Investments	11,000,000		0
Gross Realized Gains on Investment Sales	0		0
Gross Realized Losses on Investment Sales	0		0
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	1,788,000,000			1,706,000,000
Gross Unrealized Gains	418,000,000			349,000,000
Other-Than-Temporary Impairments	85,000,000			80,000,000
Securities Activity Within Decommissioning and SNF Trusts [Abstract]
Proceeds from Investment Sales	168,000,000		334,000,000
Purchases of Investments	185,000,000		353,000,000
Gross Realized Gains on Investment Sales	3,000,000		2,000,000
Gross Realized Losses on Investment Sales	2,000,000		1,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	1,788,000,000			1,706,000,000
Fair Value Measurements (Textuals) [Abstract]
Adjusted Cost of Debt Securities	900,000,000			889,000,000
Adjusted Cost of Domestic Equity Securities	456,000,000			451,000,000
Appalachian Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	3,702,599,000			3,702,442,000
Long Term Debt, Fair Value	4,507,266,000			4,555,143,000
Indiana Michigan Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	2,282,580,000			2,057,666,000
Long Term Debt, Fair Value	2,584,356,000			2,372,017,000
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	1,787,529,000			1,705,772,000
Gross Unrealized Gains	418,116,000			348,776,000
Other-Than-Temporary Impairments	84,876,000			79,519,000
Securities Activity Within Decommissioning and SNF Trusts [Abstract]
Proceeds from Investment Sales	167,670,000		334,400,000
Purchases of Investments	184,299,000		352,877,000
Gross Realized Gains on Investment Sales	3,323,000		1,552,000
Gross Realized Losses on Investment Sales	2,315,000		1,416,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	1,787,529,000			1,705,772,000
Fair Value Measurements (Textuals) [Abstract]
Adjusted Cost of Debt Securities	900,000,000			889,000,000
Adjusted Cost of Domestic Equity Securities	456,000,000			451,000,000
Ohio Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	3,560,628,000			3,860,440,000
Long Term Debt, Fair Value	4,170,595,000			4,560,337,000
Public Service Co Of Oklahoma [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	949,856,000			949,871,000
Long Term Debt, Fair Value	1,154,618,000			1,175,759,000
Southwestern Electric Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	2,044,692,000			2,046,228,000
Long Term Debt, Fair Value	2,386,875,000			2,400,509,000
Cash [Member]
Other Temporary Investments
Cost	167,000,000			241,000,000
Gross Unrealized Gains	0			0
Gross Unrealized Losses	0			0
Estimated Fair Value	167,000,000	[1]		241,000,000	[1]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	14,000,000	[2]		17,000,000	[2]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	14,000,000	[2]		17,000,000	[2]
Cash [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	13,320,000	[3]		16,783,000	[3]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	13,320,000	[3]		16,783,000	[3]
Fixed Income Funds [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	958,000,000			953,000,000
Gross Unrealized Gains	58,000,000			64,000,000
Other-Than-Temporary Impairments	4,000,000			3,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	958,000,000			953,000,000
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	958,074,000			953,407,000
Gross Unrealized Gains	57,730,000			64,177,000
Other-Than-Temporary Impairments	3,927,000			2,962,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	958,074,000			953,407,000
Mutual Funds Fixed Income [Member]
Other Temporary Investments
Cost	76,000,000			65,000,000
Gross Unrealized Gains	0			2,000,000
Gross Unrealized Losses	0			0
Estimated Fair Value	76,000,000			67,000,000
Domestic [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	816,000,000	[4]		736,000,000	[4]
Gross Unrealized Gains	360,000,000			285,000,000
Other-Than-Temporary Impairments	81,000,000			77,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	816,000,000	[4]		736,000,000	[4]
Domestic [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	816,135,000	[4]		735,582,000	[4]
Gross Unrealized Gains	360,386,000			284,599,000
Other-Than-Temporary Impairments	80,949,000			76,557,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	816,135,000	[4]		735,582,000	[4]
Mutual Funds Equity [Member]
Other Temporary Investments
Cost	10,000,000			10,000,000
Gross Unrealized Gains	8,000,000			6,000,000
Gross Unrealized Losses	0			0
Estimated Fair Value	18,000,000	[4]		16,000,000	[4]
Cash and Cash Equivalents [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	14,000,000			17,000,000
Gross Unrealized Gains	0			0
Other-Than-Temporary Impairments	0			0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	14,000,000			17,000,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	13,320,000			16,783,000
Gross Unrealized Gains	0			0
Other-Than-Temporary Impairments	0			0
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	13,320,000			16,783,000
US Government Agencies Debt Securities [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	642,000,000			648,000,000
Gross Unrealized Gains	53,000,000			58,000,000
Other-Than-Temporary Impairments	1,000,000			1,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	642,000,000			648,000,000
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	641,780,000			647,918,000
Gross Unrealized Gains	53,220,000			58,268,000
Other-Than-Temporary Impairments	907,000			747,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	641,780,000			647,918,000
Corporate Debt [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	37,000,000			35,000,000
Gross Unrealized Gains	5,000,000			5,000,000
Other-Than-Temporary Impairments	1,000,000			1,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	37,000,000			35,000,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	37,267,000			35,399,000
Gross Unrealized Gains	4,522,000			4,903,000
Other-Than-Temporary Impairments	1,353,000			1,352,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	37,267,000			35,399,000
State and Local Jurisdiction [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	279,000,000			270,000,000
Gross Unrealized Gains	0			1,000,000
Other-Than-Temporary Impairments	2,000,000			1,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	279,000,000			270,000,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	279,027,000			270,090,000
Gross Unrealized Gains	(12,000)			1,006,000
Other-Than-Temporary Impairments	1,667,000			863,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	279,027,000			270,090,000
Within One Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	95,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	95,000,000
Within One Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	95,390,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	95,390,000
One Year To Five Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	356,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	356,000,000
One Year To Five Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	355,812,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	355,812,000
Five Year To Ten Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	274,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	274,000,000
Five Year To Ten Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	273,653,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	273,653,000
After Ten Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	233,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	233,000,000
After Ten Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	233,219,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	$ 233,219,000

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

[2] Amounts in ''Other'' column primarily represent accrued interest receivables from financial institutions.

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

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