Significant Accounting Matters (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Amounts Attributable to AEP Common Shareholders
Earnings Attributable to AEP Common Shareholders	$ 629,000	$ 560,000
Weighted Average Number of Basic AEP Common Shares Outstanding	489,597,986	487,867,089
Total Basic Earnings Per Share Attributable to AEP Common Shareholders	$ 1.29	$ 1.15
Weighted Average Dilutive Effect of:
Weighted Average Number of Diluted AEP Common Shares Outstanding	489,936,726	488,271,167
Total Diluted Earnings Per Share Attributable to AEP Common Shareholders	$ 1.29	$ 1.15
Organization and Summary of Significant Accounting Policies (Textuals) [Abstract]
Antidilutive Shares Outstanding	0	0
Southwestern Electric Power Co [Member]
Amounts Attributable to AEP Common Shareholders
Earnings Attributable to AEP Common Shareholders	$ 45,704	$ 21,860
Restricted Stock Units [Member]
Weighted Average Dilutive Effect of:
Weighted Average Dilutive Effect of Shares	300,000	400,000
Dilutive Securities, Effect on Basic Earnings Per Share	$ 0	$ 0