Schedule I - Condensed Financial Information Of Registrant (Unconsolidated Statements Of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Net income	$ 71,996	$ 60,575	$ 79,947
Amortization of debt issuance costs and discounts	4,875	4,700	4,174
Loss on early extinguishment of debt		15,422
Income taxes receivable or payable	(6,681)	8,272	(5,443)
Accounts payable and accrued expenses	(2,947)	2,514	19,698
Accrued interest	971	1,777	354
Other - net	1,780	7,385	6,612
Net cash provided by operating activities	214,766	183,084	220,531
Net cash used in investing activities	(139,577)	(205,319)	(168,212)
Long-term borrowings		634,581	40,000
Dividends on common stock	(66,600)	(59,231)	(73,200)
Other - net	(6)	(637)	(334)
Net cash used in financing activities	(83,985)	17,722	(68,545)
Net change in cash and cash equivalents	(8,796)	(4,513)	(16,226)
Cash and cash equivalents at beginning of period	27,283	31,796	48,022
Cash and cash equivalents at end of period	18,487	27,283	31,796
Ipalco Enterprises, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	68,783	57,362	76,731
Equity in earnings of subsidiaries	(101,023)	(101,240)	(116,062)
Cash dividends received from subsidiary companies	96,914	80,603	111,549
Amortization of debt issuance costs and discounts	2,417	2,205	2,037
Deferred income taxes - net	22	(111)	(669)
Loss on early extinguishment of debt		15,422
Income taxes receivable or payable	(533)	160	716
Accounts payable and accrued expenses	(546)	(639)	15
Accrued interest		(800)
Other - net	166	711	(139)
Net cash provided by operating activities	66,200	53,673	74,178
Investment in subsidiaries	15	11	(73)
Net cash used in investing activities	15	11	(73)
Long-term borrowings		399,708
Retirement of long-term debt		(389,421)
Dividends on common stock	(66,600)	(59,231)	(73,200)
Other - net		(6,520)
Net cash used in financing activities	(66,600)	(55,464)	(73,200)
Net change in cash and cash equivalents	(385)	(1,780)	905
Cash and cash equivalents at beginning of period	3,135	4,915	4,010
Cash and cash equivalents at end of period	$ 2,750	$ 3,135	$ 4,915