Significant Accounting Matters (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Amounts Attributable to AEP Common Shareholders
Income (Loss) from Continuing Operations	$ (764.2)	$ 511.8	$ 245.3	$ 1,563.4
Net Income Attributable to Noncontrolling Interests	1.6	1.3	5.3	4.1
Income (Loss) from Continuing Operations Attributable to Parent	$ (765.8)	$ 510.5	$ 240.0	$ 1,559.3
Weighted Average Number of Basic AEP Common Shares Outstanding	491,697,809	490,648,929	491,422,921	490,155,315
Basic Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ (1.56)	$ 1.04	$ 0.49	$ 3.18
Weighted Average Dilutive Effect of:
Weighted Average Number of Diluted AEP Common Shares Outstanding	491,813,858	490,800,335	491,596,861	490,411,020
Diluted Earnings Per Share Attributable to AEP Common Shareholders from Continuing Operations	$ (1.56)	$ 1.04	$ 0.49	$ 3.18
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	$ 3.3	$ 3.0
Restricted Stock Units [Member]
Weighted Average Dilutive Effect of:
Weighted Average Dilutive Effect of Shares	100,000	200,000	200,000	200,000
Dilutive Securities, Effect on Basic Earnings Per Share	$ 0.0	$ 0.0	$ 0.0	$ 0.0