Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net income	$ 320	$ 309
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	329	298
Deferred tax benefit and tax credits	(42)	(29)
Equity component of allowance for funds used during construction	(6)	(27)
Other	8	27
Other changes in assets and liabilities:
Accounts receivable	(265)	(198)
Derivative assets	(68)	(16)
Regulatory liabilities	(69)	(63)
Deferred income taxes	93	82
Pension and other benefit obligations	(34)	(34)
Other	(59)	(30)
Net cash flows from operating activities	207	319
Cash flows from (used for) investing activities:
Utility business construction and acquisition expenditures	(426)	(584)
Other construction and acquisition expenditures	(32)	(24)
Cash receipts on sold receivables	295	210
Other	(27)	6
Net cash flows from (used for) investing activities	(190)	(392)
Cash flows from (used for) financing activities:
Common stock dividends	(203)	(187)
Proceeds from issuance of common stock, net	15	235
Proceeds from issuance of long-term debt	0	1,050
Payments to retire long-term debt	(4)	(654)
Net change in commercial paper	146	(152)
Other	(11)	(28)
Net cash flows from (used for) financing activities	(57)	264
Net increase (decrease) in cash, cash equivalents and restricted cash	(40)	191
Cash, cash equivalents and restricted cash at beginning of period	56	18
Cash, cash equivalents and restricted cash at end of period	16	209
Supplemental cash flows information:
Interest	(137)	(138)
Income taxes, net	(1)	(5)
Significant non-cash investing and financing activities:
Accrued capital expenditures	139	208
Beneficial interest obtained in exchange for securitized accounts receivable	154	194
IPL [Member]
Cash flows from operating activities:
Net income	170	147
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	187	175
Deferred tax benefit and tax credits	(11)	(21)
Other	(2)	(6)
Other changes in assets and liabilities:
Accounts receivable	(270)	(219)
Derivative assets	(27)	(15)
Accounts payable	1	26
Regulatory liabilities	(36)	0
Deferred income taxes	30	26
Other	(24)	(36)
Net cash flows from operating activities	18	77
Cash flows from (used for) investing activities:
Utility business construction and acquisition expenditures	(191)	(310)
Cash receipts on sold receivables	295	210
Other	(6)	(25)
Net cash flows from (used for) investing activities	98	(125)
Cash flows from (used for) financing activities:
Common stock dividends	(200)	(118)
Capital contributions from parent	50	175
Proceeds from issuance of long-term debt	0	400
Payments to retire long-term debt	0	(200)
Other	(5)	(15)
Net cash flows from (used for) financing activities	(155)	242
Net increase (decrease) in cash, cash equivalents and restricted cash	(39)	194
Cash, cash equivalents and restricted cash at beginning of period	50	9
Cash, cash equivalents and restricted cash at end of period	11	203
Supplemental cash flows information:
Interest	(69)	(72)
Income taxes, net	27	7
Significant non-cash investing and financing activities:
Accrued capital expenditures	32	94
Beneficial interest obtained in exchange for securitized accounts receivable	154	194
WPL [Member]
Cash flows from operating activities:
Net income	122	147
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	139	121
Deferred tax benefit and tax credits	(35)	(12)
Other	10	(7)
Other changes in assets and liabilities:
Accounts receivable	9	23
Derivative assets	(41)	(1)
Regulatory liabilities	(33)	(63)
Deferred income taxes	63	53
Other	(34)	(5)
Net cash flows from operating activities	200	256
Cash flows from (used for) investing activities:
Utility business construction and acquisition expenditures	(235)	(274)
Other	(18)	14
Net cash flows from (used for) investing activities	(253)	(260)
Cash flows from (used for) financing activities:
Common stock dividends	(85)	(84)
Capital contributions from parent	210	25
Proceeds from issuance of long-term debt	0	350
Payments to retire long-term debt	0	(150)
Net change in commercial paper	(65)	(130)
Other	(7)	(8)
Net cash flows from (used for) financing activities	53	3
Net increase (decrease) in cash, cash equivalents and restricted cash	0	(1)
Cash, cash equivalents and restricted cash at beginning of period	3	4
Cash, cash equivalents and restricted cash at end of period	3	3
Supplemental cash flows information:
Interest	(52)	(50)
Income taxes, net	(27)	1
Significant non-cash investing and financing activities:
Accrued capital expenditures	$ 104	$ 114