Income Taxes (Schedule Of Effective Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Federal statutory tax rate	35.00%	35.00%	35.00%
State income tax, net of federal tax benefit	7.20%	6.70%	7.70%
Amortization of investment tax credits	(1.40%)	(1.80%)	(1.40%)
Preferred dividends of subsidiary	1.00%	1.20%	0.90%
Depreciation flow through and amortization	1.40%	1.30%	0.50%
Manufacturers' Production Deduction (Sec. 199)	(3.70%)	(3.50%)	(3.40%)
Change in tax reserves	0.00%	0.00%	(0.30%)
Other - net	1.40%	0.40%	0.70%
Effective tax rate	40.90%	39.30%	39.70%
Indianapolis Power And Light Company [Member]
Federal statutory tax rate	35.00%	35.00%	35.00%
State income tax, net of federal tax benefit	6.50%	6.00%	6.80%
Amortization of investment tax credits	(0.90%)	(1.00%)	(0.90%)
Depreciation flow through and amortization	1.00%	0.70%	0.40%
Manufacturers' Production Deduction (Sec. 199)	(3.00%)	(2.40%)	(2.70%)
Change in tax reserves	0.00%	0.00%	(0.20%)
Other - net	0.90%	0.40%	0.30%
Effective tax rate	39.50%	38.70%	38.70%