Significant Accounting Matters (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Basic and Diluted EPS Calculations
Earnings Attributable to AEP Common Shareholders	$ 363,000	$ 389,000
Weighted Average Number of Basic AEP Common Shares Outstanding	485,823,668	483,828,101
Total Basic Earnings Per Share Attributable to AEP Common Shareholders	$ 0.75	$ 0.80
Weighted Average Dilutive Effect of:
Weighted Average Number of Diluted AEP Common Shares Outstanding	486,344,036	484,248,868
Total Diluted Earnings Per Share Attributable to AEP Common Shareholders	$ 0.75	$ 0.80
Amounts Attributable to AEP Common Shareholders
Net Income	363,000	389,000
Organization and Summary of Significant Accounting Policies (Textuals) [Abstract]
Antidilutive Shares Outstanding	0	0
Southwestern Electric Power Co [Member]
Basic and Diluted EPS Calculations
Earnings Attributable to AEP Common Shareholders	10,458	35,312
Amounts Attributable to AEP Common Shareholders
Net Income	$ 10,458	$ 35,312
Restricted Stock Units [Member]
Weighted Average Dilutive Effect of:
Weighted Average Dilutive Effect of Shares	500,000	400,000
Dilutive Securities, Effect on Basic Earnings Per Share	$ 0	$ 0