Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 558	$ 454
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	454	424
Deferred tax expense (benefit) and tax credits	(48)	53
Equity component of allowance for funds used during construction	(36)	(46)
Other	19	17
Other changes in assets and liabilities:
Accounts receivable	(316)	(359)
Regulatory liabilities	(72)	(12)
Deferred income taxes	143	45
Pension and other benefit obligations	(61)	(33)
DAEC PPA amendment buyout payment	(110)	0
Other	(95)	(34)
Net cash flows from operating activities	436	509
Cash flows used for investing activities:
Utility business construction and acquisition expenditures	(935)	(1,004)
Other construction and acquisition expenditures	(39)	(71)
Cash receipts on sold receivables	318	256
Other	(23)	(42)
Net cash flows used for investing activities	(679)	(861)
Cash flows from (used for) financing activities:
Common stock dividends	(281)	(253)
Proceeds from issuance of common stock, net	241	185
Proceeds from issuance of long-term debt	1,050	950
Payments to retire long-term debt	(654)	(253)
Net change in commercial paper	85	(92)
Other	(22)	(11)
Net cash flows from (used for) financing activities	419	526
Net increase (decrease) in cash, cash equivalents and restricted cash	176	174
Cash, cash equivalents and restricted cash at beginning of period	18	26
Cash, cash equivalents and restricted cash at end of period	194	200
Supplemental cash flows information:
Interest	(197)	(195)
Income taxes, net	6	1
Significant non-cash investing and financing activities:
Accrued capital expenditures	202	254
Beneficial interest obtained in exchange for securitized accounts receivable	201	237
IPL [Member]
Cash flows from operating activities:
Net income	298	247
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	264	243
Deferred tax expense (benefit) and tax credits	(42)	(14)
Equity component of allowance for funds used during construction	(15)	(25)
Other	6	2
Other changes in assets and liabilities:
Accounts receivable	(337)	(365)
Regulatory assets	(32)	(13)
Deferred income taxes	62	32
Pension and other benefit obligations	(19)	(13)
DAEC PPA amendment buyout payment	(110)	0
Other	(56)	45
Net cash flows from operating activities	19	139
Cash flows used for investing activities:
Utility business construction and acquisition expenditures	(465)	(696)
Cash receipts on sold receivables	318	256
Other	(55)	(44)
Net cash flows used for investing activities	(202)	(484)
Cash flows from (used for) financing activities:
Common stock dividends	(177)	(126)
Capital contributions from parent	345	100
Proceeds from issuance of long-term debt	400	600
Payments to retire long-term debt	(200)	0
Net change in commercial paper	0	(50)
Other	(9)	(6)
Net cash flows from (used for) financing activities	359	518
Net increase (decrease) in cash, cash equivalents and restricted cash	176	173
Cash, cash equivalents and restricted cash at beginning of period	9	12
Cash, cash equivalents and restricted cash at end of period	185	185
Supplemental cash flows information:
Interest	(109)	(94)
Income taxes, net	(12)	8
Significant non-cash investing and financing activities:
Accrued capital expenditures	150	180
Beneficial interest obtained in exchange for securitized accounts receivable	201	237
WPL [Member]
Cash flows from operating activities:
Net income	220	183
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	186	177
Deferred tax expense (benefit) and tax credits	(9)	55
Other	(8)	(8)
Other changes in assets and liabilities:
Regulatory liabilities	(61)	(29)
Deferred income taxes	79	16
Other	(5)	(34)
Net cash flows from operating activities	402	360
Cash flows used for investing activities:
Utility business construction and acquisition expenditures	(470)	(308)
Other	5	(27)
Net cash flows used for investing activities	(465)	(335)
Cash flows from (used for) financing activities:
Common stock dividends	(127)	(108)
Capital contributions from parent	25	100
Proceeds from issuance of long-term debt	350	350
Payments to retire long-term debt	(150)	(250)
Net change in commercial paper	(29)	(105)
Other	(8)	(11)
Net cash flows from (used for) financing activities	61	(24)
Net increase (decrease) in cash, cash equivalents and restricted cash	(2)	1
Cash, cash equivalents and restricted cash at beginning of period	4	9
Cash, cash equivalents and restricted cash at end of period	2	10
Supplemental cash flows information:
Interest	(71)	(74)
Income taxes, net	5	(7)
Significant non-cash investing and financing activities:
Accrued capital expenditures	$ 50	$ 70