Significant Accounting Matters (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Amounts Attributable to AEP Common Shareholders
Income from Continuing Operations	$ 503.1	$ 620.2
Net Income Attributable to Noncontrolling Interests	1.9	1.5
Income (Loss) from Continuing Operations Attributable to Parent	$ 501.2	$ 618.7
Weighted Average Number of Basic AEP Common Shares Outstanding	491,108,392	489,597,986
Basic Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ 1.02	$ 1.27
Weighted Average Dilutive Effect of:
Weighted Average Number of Diluted AEP Common Shares Outstanding	491,332,305	489,936,726
Diluted Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ 1.02	$ 1.27
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
Net Income Attributable to Noncontrolling Interests	$ 1.1	$ 1.0
Restricted Stock Units [Member]
Weighted Average Dilutive Effect of:
Weighted Average Dilutive Effect of Shares	200,000	300,000
Dilutive Securities, Effect on Basic Earnings Per Share	$ 0	$ 0