Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 108,793	$ 131,060	$ 59,524
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	208,209	218,449	188,272
Amortization (deferral) of regulatory assets	0	0	0
Amortization of redemption premiums and expense on debt	4,202	4,147	5,067
Deferred income taxes and investment tax credit adjustments - net	(3,506)	34,012	31,566
Loss on early extinguishment of debt	8,875	0	21,956
Allowance for equity funds used during construction	(25,798)	(27,140)	(14,996)
Change in certain assets and liabilities:
Accounts receivable	(2,991)	(30,420)	15,542
Fuel, materials and supplies	(5,342)	33,434	(18,372)
Income taxes receivable or payable	(12,592)	(1,603)	0
Financial transmission rights	1,861	(243)	2,086
Accounts payable and accrued expenses	(5,345)	13,668	(716)
Accrued real estate and personal property taxes	(785)	1,218	(1,465)
Accrued interest	1,791	850	965
Pension and other postretirement benefit expenses	(14,069)	(16,595)	(15,730)
Short-term and long-term regulatory assets and liabilities	17,011	(38,026)	(22,980)
Prepaids and other current assets	6,141	(1,779)	(4,949)
Other - net	(1,195)	3,559	6,655
Net cash provided by operating activities	285,260	324,591	252,425
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures - utility	(218,224)	(592,243)	(672,849)
Project development costs	(1,729)	(1,356)	(8,980)
Cost of removal, net of salvage	(12,195)	(13,403)	(12,064)
Other	(4,284)	(1,686)	(1,224)
Net cash used in investing activities	(236,432)	(608,688)	(695,117)
CASH FLOWS FROM FINANCING ACTIVITIES:
Short-term debt borrowings	202,500	298,000	388,850
Short-term debt repayments	(129,150)	(414,850)	(272,000)
Long-term borrowings, net of discount	404,633	387,662	753,350
Retirement of long-term debt and early tender premium	(408,152)	(40,000)	(552,179)
Dividends on common stock	(105,144)	(122,959)	(69,487)
Issuance of common stock	0	134,276	214,366
Proceeds from Contributed Capital	0	78,738	0
Dividends on preferred stock	(3,213)	(3,213)	(3,213)
Deferred financing costs paid	(3,709)	(4,499)	(8,824)
Payments for financed capital expenditures	(10,637)	(15,473)	(13,215)
Other	(228)	(153)	(368)
Net cash (used in) provided by financing activities	(53,100)	297,529	437,280
Net change in cash and cash equivalents	(4,272)	13,432	(5,412)
Cash and cash equivalents at beginning of period	34,953	21,521	26,933
Cash and cash equivalents at end of period	30,681	34,953	21,521
Cash paid during the period for:
Interest (net of amount capitalized)	94,781	89,098	95,137
Income taxes	65,050	28,800	0
Non-cash investing activities:
Accruals for capital expenditures	45,322	36,249	79,553
Indianapolis Power And Light Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	136,515	156,445	101,921
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	208,209	218,449	188,272
Amortization of redemption premiums and expense on debt	2,199	2,200	2,608
Deferred income taxes and investment tax credit adjustments - net	(3,441)	11,165	33,756
Allowance for equity funds used during construction	(25,798)	(27,140)	(14,996)
Change in certain assets and liabilities:
Accounts receivable	(2,991)	(30,420)	15,542
Fuel, materials and supplies	(5,342)	33,434	(18,372)
Income taxes receivable or payable	(17,968)	3,821	(2,544)
Financial transmission rights	1,861	(243)	2,086
Accounts payable and accrued expenses	(3,512)	13,891	(356)
Accrued real estate and personal property taxes	(785)	1,218	(1,465)
Accrued interest	(245)	1,627	996
Pension and other postretirement benefit expenses	(14,069)	(16,595)	(15,730)
Short-term and long-term regulatory assets and liabilities	17,011	(38,026)	(22,980)
Prepaids and other current assets	6,185	(1,910)	(4,671)
Other - net	(1,864)	3,511	5,895
Net cash provided by operating activities	295,965	331,427	269,962
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures - utility	(218,224)	(592,243)	(672,849)
Project development costs	(1,729)	(1,356)	(8,980)
Cost of removal, net of salvage	(12,195)	(13,403)	(12,064)
Other	(4,730)	(1,703)	(1,224)
Net cash used in investing activities	(236,878)	(608,705)	(695,117)
CASH FLOWS FROM FINANCING ACTIVITIES:
Short-term debt borrowings	202,500	298,000	388,850
Short-term debt repayments	(129,150)	(414,850)	(272,000)
Long-term borrowings, net of discount	0	387,662	348,638
Retirement of long-term debt and early tender premium	0	(40,000)	(131,850)
Dividends on common stock	(132,516)	(136,466)	(103,747)
Dividends on preferred stock	(3,213)	(3,213)	(3,213)
Proceeds from Contributions from Parent	0	213,014	214,364
Payments for financed capital expenditures	(10,637)	(15,473)	(13,215)
Other	(336)	(4,641)	(3,819)
Net cash (used in) provided by financing activities	(73,352)	284,033	424,008
Net change in cash and cash equivalents	(14,265)	6,755	(1,147)
Cash and cash equivalents at beginning of period	26,607
Cash and cash equivalents at end of period	12,342	26,607
Cash paid during the period for:
Interest (net of amount capitalized)	63,031	54,350	53,447
Income taxes	87,000	57,900	25,000
Non-cash investing activities:
Accruals for capital expenditures	$ 45,322	$ 36,249	$ 79,553