Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
ASSETS
Utility plant in service	$ 4,382,534	$ 4,313,015
Less accumulated depreciation	2,043,540	1,940,633
Utility plant in service - net	2,338,994	2,372,382
Construction work in progress	70,169	52,429
Spare parts inventory	15,445	15,534
Property held for future use	1,002	1,002
Utility plant - net	2,425,610	2,441,347
OTHER ASSETS:
Nonutility property - at cost, less accumulated depreciation	533	539
Other investments	5,333	5,029
Other assets - net	5,866	5,568
CURRENT ASSETS:
Cash and cash equivalents	18,487	27,283
Accounts receivable and unbilled revenue (less allowance for doubtful accounts of $2,047 and $2,081, respectively)	141,508	136,007
Fuel inventories - at average cost	45,236	52,694
Materials and supplies - at average cost	57,256	54,137
Deferred tax asset - current	10,809	12,352
Regulatory assets	4,906	7,424
Prepayments and other current assets	21,135	16,838
Total current assets	299,337	306,735
DEFERRED DEBITS:
Regulatory assets	523,839	485,932
Miscellaneous	30,695	32,070
Total deferred debits	554,534	518,002
TOTAL	3,285,347	3,271,652
CAPITALIZATION AND LIABILITIES
Paid in capital	11,811	11,367
Accumulated deficit	(15,030)	(17,213)
Total common shareholder's equity (deficit)	(3,219)	(5,846)
Cumulative preferred stock of subsidiary	59,784	59,784
Long-term debt (Note 9)	1,651,120	1,760,316
Total capitalization	1,707,685	1,814,254
CURRENT LIABILITIES:
Short-term (Note 9)	160,000	64,000
Accounts payable	76,343	81,206
Accrued expenses	24,310	24,138
Accrued real estate and personal property taxes	19,405	17,460
Regulatory liabilities	10,475	9,263
Accrued interest	31,979	31,008
Customer deposits	24,796	23,142
Other current liabilities	11,210	14,236
Total current liabilities	358,518	264,453
DEFERRED CREDITS AND OTHER LONG-TERM LIABILITIES:
Regulatory liabilities	570,344	550,432
Accumulated deferred income taxes - net	341,859	351,161
Non-current income tax liability	6,138	5,354
Unamortized investment tax credit	8,162	9,761
Accrued pension and other postretirement benefits	274,017	258,171
Miscellaneous	18,624	18,066
Total deferred credits and other long-term liabilities	1,219,144	1,192,945
COMMITMENTS AND CONTINGENCIES (Note 12)
TOTAL	3,285,347	3,271,652
Indianapolis Power And Light Company [Member]
ASSETS
Utility plant in service	4,382,534	4,313,015
Less accumulated depreciation	2,043,540	1,940,633
Utility plant in service - net	2,338,994	2,372,382
Construction work in progress	70,169	52,429
Spare parts inventory	15,445	15,534
Property held for future use	1,002	1,002
Utility plant - net	2,425,610	2,441,347
OTHER ASSETS:
Nonutility property - at cost, less accumulated depreciation	1,123	944
CURRENT ASSETS:
Cash and cash equivalents	12,042	20,606
Accounts receivable and unbilled revenue (less allowance for doubtful accounts of $2,047 and $2,081, respectively)	141,508	136,007
Fuel inventories - at average cost	45,236	52,694
Materials and supplies - at average cost	57,257	54,137
Deferred tax asset - current	10,782	12,323
Regulatory assets	4,906	7,424
Prepayments and other current assets	22,045	16,474
Total current assets	293,776	299,665
DEFERRED DEBITS:
Regulatory assets	523,839	485,932
Miscellaneous	22,507	22,344
Total deferred debits	546,346	508,276
TOTAL	3,266,855	3,250,232
CAPITALIZATION AND LIABILITIES
Common stock	324,537	324,537
Paid in capital	13,536	13,114
Accumulated deficit	448,162	443,946
Total common shareholder's equity (deficit)	786,235	781,597
Cumulative preferred stock of subsidiary	59,784	59,784
Long-term debt (Note 9)	854,204	964,175
Total capitalization	1,700,223	1,805,556
CURRENT LIABILITIES:
Short-term (Note 9)	160,000	64,000
Accounts payable	76,282	81,175
Accrued expenses	24,226	24,049
Accrued real estate and personal property taxes	19,405	17,460
Regulatory liabilities	10,475	9,263
Accrued interest	21,362	20,391
Customer deposits	24,796	23,142
Other current liabilities	10,910	11,923
Total current liabilities	347,456	251,403
DEFERRED CREDITS AND OTHER LONG-TERM LIABILITIES:
Regulatory liabilities	570,344	550,432
Accumulated deferred income taxes - net	341,914	351,510
Non-current income tax liability	6,138	5,354
Unamortized investment tax credit	8,162	9,761
Accrued pension and other postretirement benefits	274,017	258,171
Miscellaneous	18,601	18,045
Total deferred credits and other long-term liabilities	1,219,176	1,193,273
COMMITMENTS AND CONTINGENCIES (Note 12)
TOTAL	$ 3,266,855	$ 3,250,232