Regulatory Assets And Liabilities (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Regulatory Assets And Liabilities [Line Items]
Regulatory assets, current	$ 4,906,000	$ 7,424,000
Increase in deferred fuel asset	5,800,000
Deferred Fuel Over/Under-Collection [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets, current	1,332,000	7,098,000
Indianapolis Power And Light Company [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets, current	4,906,000	7,424,000
Increase in deferred fuel asset	5,800,000
Indianapolis Power And Light Company [Member] | Deferred Fuel Over/Under-Collection [Member]
Regulatory Assets And Liabilities [Line Items]
Regulatory assets, current	$ 1,332,000	$ 7,098,000
Maximum [Member]
Regulatory Assets And Liabilities [Line Items]
Amortization period of regulatory assets	35 years
Maximum [Member] | Indianapolis Power And Light Company [Member]
Regulatory Assets And Liabilities [Line Items]
Amortization period of regulatory assets	35 years
Minimum [Member]
Regulatory Assets And Liabilities [Line Items]
Amortization period of regulatory assets	1 year
Minimum [Member] | Indianapolis Power And Light Company [Member]
Regulatory Assets And Liabilities [Line Items]
Amortization period of regulatory assets	1 year