Fair Value Long-term Debt, Other Temporary Investments, Nuclear Trusts (Details) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012	Dec. 31, 2012
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	$ 17,618,000,000			$ 17,618,000,000			$ 17,757,000,000
Long Term Debt, Fair Value	19,509,000,000			19,509,000,000			20,907,000,000
Other Temporary Investments
Cost	290,000,000			290,000,000			316,000,000
Gross Unrealized Gains	8,000,000			8,000,000			8,000,000
Gross Unrealized Losses	0			0			0
Estimated Fair Value	298,000,000			298,000,000			324,000,000
Debt and Equity Securities Within Other Temporary Investments [Abstract]
Proceeds from Investment Sales	0		0	0		0
Purchases of Investments	0		1,000,000	11,000,000		1,000,000
Gross Realized Gains on Investment Sales	0		0	0		0
Gross Realized Losses on Investment Sales	0		0	0		0
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	1,791,000,000			1,791,000,000			1,706,000,000
Gross Unrealized Gains	413,000,000			413,000,000			349,000,000
Other-Than-Temporary Impairments	89,000,000			89,000,000			80,000,000
Securities Activity Within Decommissioning and SNF Trusts [Abstract]
Proceeds from Investment Sales	217,000,000		183,000,000	385,000,000		517,000,000
Purchases of Investments	227,000,000		192,000,000	412,000,000		545,000,000
Gross Realized Gains on Investment Sales	9,000,000		3,000,000	12,000,000		5,000,000
Gross Realized Losses on Investment Sales	8,000,000		1,000,000	10,000,000		2,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	1,791,000,000			1,791,000,000			1,706,000,000
Fair Value Measurements (Textuals) [Abstract]
Adjusted Cost of Debt Securities	862,000,000			862,000,000			889,000,000
Adjusted Cost of Domestic Equity Securities	502,000,000			502,000,000			451,000,000
Appalachian Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	3,702,759,000			3,702,759,000			3,702,442,000
Long Term Debt, Fair Value	4,241,900,000			4,241,900,000			4,555,143,000
Indiana Michigan Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	2,305,192,000			2,305,192,000			2,057,666,000
Long Term Debt, Fair Value	2,490,561,000			2,490,561,000			2,372,017,000
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	1,791,394,000			1,791,394,000			1,705,772,000
Gross Unrealized Gains	411,502,000			411,502,000			348,776,000
Other-Than-Temporary Impairments	88,657,000			88,657,000			79,519,000
Securities Activity Within Decommissioning and SNF Trusts [Abstract]
Proceeds from Investment Sales	218,272,000		182,179,000	385,942,000		516,579,000
Purchases of Investments	227,470,000		192,104,000	411,769,000		544,981,000
Gross Realized Gains on Investment Sales	8,575,000		3,380,000	11,898,000		4,932,000
Gross Realized Losses on Investment Sales	7,397,000		803,000	9,712,000		2,219,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	1,791,394,000			1,791,394,000			1,705,772,000
Fair Value Measurements (Textuals) [Abstract]
Adjusted Cost of Debt Securities	862,000,000			862,000,000			889,000,000
Adjusted Cost of Domestic Equity Securities	502,000,000			502,000,000			451,000,000
Ohio Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	3,504,794,000			3,504,794,000			3,860,440,000
Long Term Debt, Fair Value	4,002,270,000			4,002,270,000			4,560,337,000
Public Service Co Of Oklahoma [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	949,841,000			949,841,000			949,871,000
Long Term Debt, Fair Value	1,107,094,000			1,107,094,000			1,175,759,000
Southwestern Electric Power Co [Member]
Book Values and Fair Values of Long - term Debt
Total Long-term Debt Outstanding	2,044,780,000			2,044,780,000			2,046,228,000
Long Term Debt, Fair Value	2,231,426,000			2,231,426,000			2,400,509,000
Cash [Member]
Other Temporary Investments
Cost	204,000,000			204,000,000			241,000,000
Gross Unrealized Gains	0			0			0
Gross Unrealized Losses	0			0			0
Estimated Fair Value	204,000,000	[1]		204,000,000	[1]		241,000,000	[1]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	14,000,000	[2]		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]		14,000,000	[2]		17,000,000	[2]
Cash [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	14,132,000	[3]		14,132,000	[3]		16,783,000	[3]
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	14,132,000	[3]		14,132,000	[3]		16,783,000	[3]
Fixed Income Funds [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	902,000,000			902,000,000			953,000,000
Gross Unrealized Gains	40,000,000			40,000,000			64,000,000
Other-Than-Temporary Impairments	7,000,000			7,000,000			3,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	902,000,000			902,000,000			953,000,000
Fixed Income Funds [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	902,573,000			902,573,000			953,407,000
Gross Unrealized Gains	38,911,000			38,911,000			64,177,000
Other-Than-Temporary Impairments	6,509,000			6,509,000			2,962,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	902,573,000			902,573,000			953,407,000
Mutual Funds Fixed Income [Member]
Other Temporary Investments
Cost	76,000,000			76,000,000			65,000,000
Gross Unrealized Gains	0			0			2,000,000
Gross Unrealized Losses	0			0			0
Estimated Fair Value	76,000,000			76,000,000			67,000,000
Domestic [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	875,000,000	[4]		875,000,000	[4]		736,000,000	[4]
Gross Unrealized Gains	373,000,000			373,000,000			285,000,000
Other-Than-Temporary Impairments	82,000,000			82,000,000			77,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	875,000,000	[4]		875,000,000	[4]		736,000,000	[4]
Domestic [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	874,689,000	[4]		874,689,000	[4]		735,582,000	[4]
Gross Unrealized Gains	372,591,000			372,591,000			284,599,000
Other-Than-Temporary Impairments	82,148,000			82,148,000			76,557,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	874,689,000	[4]		874,689,000	[4]		735,582,000	[4]
Mutual Funds Equity [Member]
Other Temporary Investments
Cost	10,000,000			10,000,000			10,000,000
Gross Unrealized Gains	8,000,000			8,000,000			6,000,000
Gross Unrealized Losses	0			0			0
Estimated Fair Value	18,000,000	[4]		18,000,000	[4]		16,000,000	[4]
Cash and Cash Equivalents [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	14,000,000			14,000,000			17,000,000
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	14,000,000			14,000,000			17,000,000
Cash and Cash Equivalents [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	14,132,000			14,132,000			16,783,000
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	14,132,000			14,132,000			16,783,000
US Government Agencies Debt Securities [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	605,000,000			605,000,000			648,000,000
Gross Unrealized Gains	37,000,000			37,000,000			58,000,000
Other-Than-Temporary Impairments	2,000,000			2,000,000			1,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	605,000,000			605,000,000			648,000,000
US Government Agencies Debt Securities [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	604,850,000			604,850,000			647,918,000
Gross Unrealized Gains	37,609,000			37,609,000			58,268,000
Other-Than-Temporary Impairments	2,085,000			2,085,000			747,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	604,850,000			604,850,000			647,918,000
Corporate Debt [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	35,000,000			35,000,000			35,000,000
Gross Unrealized Gains	3,000,000			3,000,000			5,000,000
Other-Than-Temporary Impairments	2,000,000			2,000,000			1,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	35,000,000			35,000,000			35,000,000
Corporate Debt [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	35,202,000			35,202,000			35,399,000
Gross Unrealized Gains	2,963,000			2,963,000			4,903,000
Other-Than-Temporary Impairments	1,592,000			1,592,000			1,352,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	35,202,000			35,202,000			35,399,000
State and Local Jurisdiction [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	262,000,000			262,000,000			270,000,000
Gross Unrealized Gains	0			0			1,000,000
Other-Than-Temporary Impairments	3,000,000			3,000,000			1,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	262,000,000			262,000,000			270,000,000
State and Local Jurisdiction [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	262,521,000			262,521,000			270,090,000
Gross Unrealized Gains	(1,661,000)			(1,661,000)			1,006,000
Other-Than-Temporary Impairments	2,832,000			2,832,000			863,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	262,521,000			262,521,000			270,090,000
Within One Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	79,000,000			79,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	79,000,000			79,000,000
Within One Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	78,832,000			78,832,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	78,832,000			78,832,000
One Year To Five Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	340,000,000			340,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	340,000,000			340,000,000
One Year To Five Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	340,397,000			340,397,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	340,397,000			340,397,000
Five Year To Ten Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	238,000,000			238,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	238,000,000			238,000,000
Five Year To Ten Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	238,064,000			238,064,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	238,064,000			238,064,000
After Ten Year [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	245,000,000			245,000,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	245,000,000			245,000,000
After Ten Year [Member] | Indiana Michigan Power Co [Member]
Nuclear Trust Fund Investments [Abstract]
Estimated Fair Value	245,280,000			245,280,000
Contractual Maturities, Fair Value of Debt Securities
Contractual Maturities, Fair Value of Debt Securities	$ 245,280,000			$ 245,280,000

[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. Level 1 amounts primarily represent investments in money market funds.

[3] Amounts in “Other” column primarily represent accrued interest receivables from financial institutions. Level 1 amounts primarily represent investments in money market funds.

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