Significant Accounting Matters (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Amounts Attributable to AEP Common Shareholders
Income (Loss) from Continuing Operations	$ 506.4	$ 431.4	$ 1,009.5	$ 1,051.6
Net Income Attributable to Noncontrolling Interests	1.8	1.3	3.7	2.8
Income (Loss) from Continuing Operations Attributable to Parent	$ 504.6	$ 430.1	$ 1,005.8	$ 1,048.8
Weighted Average Number of Basic AEP Common Shares Outstanding	491,459,541	490,207,482	491,283,967	489,904,417
Basic Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ 1.03	$ 0.88	$ 2.05	$ 2.14
Weighted Average Dilutive Effect of:
Weighted Average Number of Diluted AEP Common Shares Outstanding	491,641,400	490,484,450	491,486,853	490,212,271
Diluted Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ 1.03	$ 0.88	$ 2.05	$ 2.14
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	$ 2.2	$ 2.0
Restricted Stock Units [Member]
Weighted Average Dilutive Effect of:
Weighted Average Dilutive Effect of Shares	100,000	300,000	200,000	300,000
Dilutive Securities, Effect on Basic Earnings Per Share	$ 0.0	$ 0.0	$ 0.0	$ 0.0