Consolidated Statements Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Cash flows from operating activities:
Net income	$ 810	$ 690	$ 703
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	846	772	676
Deferred tax expense (benefit) and tax credits	(158)	(117)	14
Asset valuation charge for IPL's Lansing Generating Station	0	60	0
Other	27	(22)	(39)
Other changes in assets and liabilities:
Accounts receivable	(652)	(547)	(414)
Derivative assets	6	13	149
Accounts payable	14	96	(122)
Regulatory liabilities	140	(103)	(149)
Deferred income taxes	252	259	84
Other	(116)	66	(35)
Net cash flows from operating activities	1,169	1,167	867
Cash flows from (used for) investing activities:
Utility construction and acquisition expenditures	(2,277)	(2,052)	(1,731)
Other construction and acquisition expenditures	(206)	(197)	(123)
Cash receipts on sold receivables	628	593	453
Proceeds from sales of partial ownership interests in West Riverside	0	123	120
Other	(41)	(14)	(120)
Net cash flows from (used for) investing activities	(1,896)	(1,547)	(1,401)
Cash flows from (used for) financing activities:
Common stock dividends	(521)	(492)	(456)
Proceeds from issuance of common stock, net	23	23	246
Proceeds from issuance of long-term debt	2,470	1,613	1,455
Payments to retire long-term debt	(300)	(809)	(508)
Net change in commercial paper	(470)	83	(167)
Other	0	(20)	3
Net cash flows from (used for) financing activities	1,202	398	573
Net increase (decrease) in cash, cash equivalents and restricted cash	475	18	39
Cash, cash equivalents and restricted cash at beginning of period	81	63	24
Cash, cash equivalents and restricted cash at end of period	556	81	63
Supplemental cash flows information:
Interest	(500)	(434)	(378)
Income taxes, net	266	197	88
Significant non-cash investing and financing activities:
Accrued capital expenditures	178	224	364
Beneficial interest obtained in exchange for securitized accounts receivable	126	163	216
Federal [Member]
Supplemental cash flows information:
Income taxes, net	271	202	82
Iowa State [Member]
Supplemental cash flows information:
Income taxes, net	(5)	(5)	6
Indemnification Agreement [Member] | Renewable Tax Credits Transferred [Member]
Supplemental cash flows information:
Proceeds from renewable tax credits transferred to other corporate taxpayers	285	216	98
IPL [Member]
Cash flows from operating activities:
Net income	457	362	366
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	463	404	388
Deferred tax expense (benefit) and tax credits	(96)	(91)	8
Asset valuation charge for IPL's Lansing Generating Station	0	60	0
Other	(25)	(12)	(10)
Other changes in assets and liabilities:
Accounts receivable	(599)	(544)	(437)
Regulatory assets	(72)	(2)	58
Derivative assets	4	6	84
Regulatory liabilities	20	(61)	(92)
Deferred income taxes	194	178	36
Other	(60)	57	(140)
Net cash flows from operating activities	286	357	261
Cash flows from (used for) investing activities:
Utility construction and acquisition expenditures	(1,473)	(1,224)	(712)
Cash receipts on sold receivables	628	593	453
Other	(14)	(53)	(67)
Net cash flows from (used for) investing activities	(859)	(684)	(326)
Cash flows from (used for) financing activities:
Common stock dividends	(359)	(200)	(280)
Capital contributions from parent	285	325	80
Proceeds from issuance of long-term debt	888	643	296
Payments to retire long-term debt	(300)	(500)	0
Net change in commercial paper	38	50	0
Other	(1)	(15)	7
Net cash flows from (used for) financing activities	551	303	103
Net increase (decrease) in cash, cash equivalents and restricted cash	(22)	(24)	38
Cash, cash equivalents and restricted cash at beginning of period	29	53	15
Cash, cash equivalents and restricted cash at end of period	7	29	53
Supplemental cash flows information:
Interest	(212)	(169)	(150)
Income taxes, net	139	175	117
Significant non-cash investing and financing activities:
Accrued capital expenditures	98	128	140
Beneficial interest obtained in exchange for securitized accounts receivable	126	163	216
IPL [Member] | Federal [Member]
Supplemental cash flows information:
Income taxes, net	142	164	98
IPL [Member] | Iowa State [Member]
Supplemental cash flows information:
Income taxes, net	(3)	11	19
IPL [Member] | Indemnification Agreement [Member] | Renewable Tax Credits Transferred [Member]
Supplemental cash flows information:
Proceeds from renewable tax credits transferred to other corporate taxpayers	140	117	76
WPL [Member]
Cash flows from operating activities:
Net income	401	345	345
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	370	357	280
Other	(63)	(51)	(47)
Other changes in assets and liabilities:
Accounts receivable	(56)	(5)	23
Regulatory assets	43	72	(34)
Regulatory liabilities	120	(41)	(57)
Deferred income taxes	40	84	50
Other	(19)	0	18
Net cash flows from operating activities	836	761	578
Cash flows from (used for) investing activities:
Utility construction and acquisition expenditures	(804)	(828)	(1,019)
Proceeds from sales of partial ownership interests in West Riverside	0	123	120
Other	(23)	(19)	(47)
Net cash flows from (used for) investing activities	(827)	(724)	(946)
Cash flows from (used for) financing activities:
Common stock dividends	(207)	(196)	(184)
Capital contributions from parent	80	55	245
Proceeds from issuance of long-term debt	296	297	297
Net change in commercial paper	(183)	(135)	28
Other	(9)	(14)	(16)
Net cash flows from (used for) financing activities	(23)	7	370
Net increase (decrease) in cash, cash equivalents and restricted cash	(14)	44	2
Cash, cash equivalents and restricted cash at beginning of period	51	7	5
Cash, cash equivalents and restricted cash at end of period	37	51	7
Supplemental cash flows information:
Interest	(176)	(163)	(146)
Income taxes, net	109	14	(50)
Significant non-cash investing and financing activities:
Accrued capital expenditures	71	87	217
WPL [Member] | Federal [Member]
Supplemental cash flows information:
Income taxes, net	124	41	(25)
WPL [Member] | State Taxes - Wisconsin [Member]
Supplemental cash flows information:
Income taxes, net	(15)	(27)	(25)
WPL [Member] | Indemnification Agreement [Member] | Renewable Tax Credits Transferred [Member]
Supplemental cash flows information:
Proceeds from renewable tax credits transferred to other corporate taxpayers	$ 145	$ 99	$ 22