Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Changes in Carrying Amount of Goodwill

		Corporate and Other		Generation & Marketing		AEP Consolidated
	(in millions)
Balance as of December 31, 2015		$	37.1	$	15.4	$	52.5
Impairment Losses		—		—		—
Balance as of December 31, 2016		37.1		15.4		52.5
Impairment Losses		—		—		—
Balance as of December 31, 2017		$	37.1	$	15.4	$	52.5

Amortization Life, Gross Carrying Amount and Accumulated Amortization by Major Asset Class

		December 31, 2016
	Amortization Life	Gross Carrying Amount		Accumulated Amortization
	(in years)	(in millions)
Acquired Customer Contracts	5	$	58.3	$	58.3