Alliant Energy (LNT) 10-Q 5 Aug 22 2022 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information	6 Months Ended
	Jun. 30, 2022 shares
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2022
Document Transition Report	false
Entity Registrant Name	ALLIANT ENERGY CORP
Entity Central Index Key	0000352541
Entity Incorporation, State or Country Code	WI
Entity Address, Address Line One	4902 N. Biltmore Lane
Entity Address, City or Town	Madison
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	53718
City Area Code	608
Local Phone Number	458-3311
Entity File Number	1-9894
Entity Tax Identification Number	39-1380265
Title of 12(b) Security	Common Stock, $0.01 Par Value
Trading Symbol	LNT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	250,926,232
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Amendment Flag	false
IPL [Member]
Entity Information [Line Items]
Entity Registrant Name	INTERSTATE POWER & LIGHT CO
Entity Central Index Key	0000052485
Entity Incorporation, State or Country Code	IA
Entity Address, Address Line One	Alliant Energy Tower
Entity Address, City or Town	Cedar Rapids
Entity Address, State or Province	IA
Entity Address, Postal Zip Code	52401
City Area Code	319
Local Phone Number	786-4411
Entity File Number	1-4117
Entity Tax Identification Number	42-0331370
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	13,370,788
WPL [Member]
Entity Information [Line Items]
Entity Registrant Name	WISCONSIN POWER & LIGHT CO
Entity Central Index Key	0000107832
Entity Incorporation, State or Country Code	WI
Entity Address, Address Line One	4902 N. Biltmore Lane
Entity Address, City or Town	Madison
Entity Address, State or Province	WI
Entity Address, Postal Zip Code	53718
City Area Code	608
Local Phone Number	458-3311
Entity File Number	0-337
Entity Tax Identification Number	39-0714890
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	13,236,601

Condensed Consolidated Statemen

Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Electric utility	$ 812	$ 717	$ 1,586	$ 1,418
Gas utility	94	69	356	239
Other utility	13	10	23	23
Non-utility	24	21	47	38
Total revenues	943	817	2,012	1,718
Operating expenses:
Electric production fuel and purchased power	191	138	359	271
Electric transmission service	133	121	271	255
Cost of gas sold	48	31	216	131
Other operation and maintenance	166	160	320	306
Depreciation and amortization	166	165	332	329
Taxes other than income taxes	27	26	54	52
Total operating expenses	731	641	1,552	1,344
Operating income	212	176	460	374
Other (income) and deductions:
Interest expense	78	69	152	138
Equity income from unconsolidated investments, net	(16)	(19)	(32)	(34)
Allowance for funds used during construction	(13)	(5)	(24)	(9)
Other	0	2	1	4
Total other (income) and deductions	49	47	97	99
Income before income taxes	163	129	363	275
Income tax expense (benefit)	4	(17)	12	(45)
Net income	159	146	351	320
Preferred dividend requirements of Interstate Power and Light Company	0	2	0	5
Net income attributable to common shareowners	$ 159	$ 144	$ 351	$ 315
Weighted average number of common shares outstanding:
Basic (in shares)	250,900	250,200	250,700	250,100
Diluted (in shares)	251,100	250,600	251,000	250,500
Earnings per weighted average common share attributable to Alliant Energy common shareowners:
Basic (in dollars per share)	$ 0.63	$ 0.58	$ 1.40	$ 1.26
Diluted (in dollars per share)	$ 0.63	$ 0.57	$ 1.40	$ 1.26
IPL [Member]
Revenues:
Electric utility	$ 442	$ 402	$ 843	$ 788
Gas utility	52	43	191	134
Other utility	12	10	22	22
Total revenues	506	455	1,056	944
Operating expenses:
Electric production fuel and purchased power	83	55	150	114
Electric transmission service	91	79	188	171
Cost of gas sold	27	22	112	72
Other operation and maintenance	87	81	171	158
Depreciation and amortization	95	93	189	187
Taxes other than income taxes	14	14	28	28
Total operating expenses	397	344	838	730
Operating income	109	111	218	214
Other (income) and deductions:
Interest expense	37	34	74	69
Allowance for funds used during construction	(3)	(3)	(5)	(5)
Other	0	2	(1)	2
Total other (income) and deductions	34	33	68	66
Income before income taxes	75	78	150	148
Income tax expense (benefit)	(12)	(10)	(23)	(22)
Net income	87	88	173	170
Preferred dividend requirements of Interstate Power and Light Company	0	2	0	5
Net income attributable to common shareowners	87	86	173	165
WPL [Member]
Revenues:
Electric utility	370	315	743	630
Gas utility	42	26	165	105
Other utility	1	0	1	1
Total revenues	413	341	909	736
Operating expenses:
Electric production fuel and purchased power	108	84	209	158
Electric transmission service	41	42	83	84
Cost of gas sold	21	9	104	59
Other operation and maintenance	67	69	123	128
Depreciation and amortization	69	70	139	139
Taxes other than income taxes	12	12	24	23
Total operating expenses	318	286	682	591
Operating income	95	55	227	145
Other (income) and deductions:
Interest expense	28	26	55	52
Allowance for funds used during construction	(10)	(2)	(18)	(4)
Other	0	0	0	1
Total other (income) and deductions	18	24	37	49
Income before income taxes	77	31	190	96
Income tax expense (benefit)	14	(7)	34	(26)
Net income	$ 63	$ 38	$ 156	$ 122

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2022		Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 19		$ 39
Accounts receivable, less allowance for expected credit losses	490		440
Production fuel, at weighted average cost	55		51
Gas stored underground, at weighted average cost	64		82
Materials and supplies, at weighted average cost	121		113
Regulatory assets	188		104
Other	371		240
Total current assets	1,308	[1]	1,069
Property, plant and equipment, net	15,453	[1]	14,987
Investments:
ATC Holdings	351		338
Other	195		179
Total investments	546		517
Other assets:
Regulatory assets	1,863		1,836
Deferred charges and other	221		144
Total other assets	2,084		1,980
Total assets	19,391		18,553
Current liabilities:
Current maturities of long-term debt	733		633
Commercial paper	399		515
Accounts payable	584		436
Accrued taxes	58		58
Regulatory liabilities	218		186
Other	284		226
Total current liabilities	2,276		2,054
Long-term debt, net (excluding current portion)	6,981		6,735
Other liabilities:
Deferred tax liabilities	1,971		1,927
Regulatory liabilities	1,145		1,085
Pension and other benefit obligations	356		374
Other	496		388
Total other liabilities	3,968	[1]	3,774
Commitments and contingencies (Note 13)
Common equity:
Common stock	3		3
Additional paid-in capital	2,759		2,749
Retained earnings	3,387		3,250
Shares in deferred compensation trust - 388,363 and 383,532 shares at a weighted average cost of $31.72 and $30.59 per share	(12)		(12)
Total common equity	6,137		5,990
Noncontrolling interest	29		0
Total equity	6,166		5,990
Total liabilities and equity	19,391		18,553
Consolidated Variable Interest Entity [Member]
Current assets:
Total current assets	1
Property, plant and equipment, net	428
Other liabilities:
Total other liabilities	8
IPL [Member]
Current assets:
Cash and cash equivalents	13		34
Accounts receivable, less allowance for expected credit losses	269		241
Income tax refunds receivable	8		8
Production fuel, at weighted average cost	37		29
Gas stored underground, at weighted average cost	27		40
Materials and supplies, at weighted average cost	73		70
Regulatory assets	111		73
Other	149		69
Total current assets	687		564
Property, plant and equipment, net	7,997		7,983
Other assets:
Regulatory assets	1,379		1,370
Deferred charges and other	121		79
Total other assets	1,500		1,449
Total assets	10,184		9,996
Current liabilities:
Accounts payable	225		173
Accounts payable to associated companies	37		39
Accrued taxes	51		56
Accrued interest	35		36
Regulatory liabilities	100		84
Other	115		67
Total current liabilities	563		455
Long-term debt, net (excluding current portion)	3,645		3,643
Other liabilities:
Deferred tax liabilities	1,106		1,083
Regulatory liabilities	651		607
Pension and other benefit obligations	121		127
Other	316		312
Total other liabilities	2,194		2,129
Commitments and contingencies (Note 13)
Common equity:
Common stock	33		33
Additional paid-in capital	2,807		2,807
Retained earnings	942		929
Total common equity	3,782		3,769
Total equity	3,782		3,769
Total liabilities and equity	10,184		9,996
WPL [Member]
Current assets:
Cash and cash equivalents	4		2
Accounts receivable, less allowance for expected credit losses	208		188
Production fuel, at weighted average cost	18		23
Gas stored underground, at weighted average cost	37		42
Materials and supplies, at weighted average cost	46		41
Regulatory assets	77		31
Prepaid gross receipts tax	40		40
Other	113		86
Total current assets	543	[2]	453
Property, plant and equipment, net	6,985	[2]	6,538
Other assets:
Regulatory assets	484		466
Deferred charges and other	106		61
Total other assets	590		527
Total assets	8,118		7,518
Current liabilities:
Current maturities of long-term debt	250		250
Commercial paper	222		236
Accounts payable	300		190
Accounts payable to associated companies	20		39
Regulatory liabilities	118		102
Other	99		73
Total current liabilities	1,009		890
Long-term debt, net (excluding current portion)	2,180		2,179
Other liabilities:
Deferred tax liabilities	774		753
Regulatory liabilities	494		478
Pension and other benefit obligations	151		159
Other	327		236
Total other liabilities	1,746	[2]	1,626
Commitments and contingencies (Note 13)
Common equity:
Common stock	66		66
Additional paid-in capital	1,968		1,704
Retained earnings	1,120		1,053
Total common equity	3,154		2,823
Noncontrolling interest	29		0
Total equity	3,183		2,823
Total liabilities and equity	8,118		$ 7,518
WPL [Member] | Consolidated Variable Interest Entity [Member]
Current assets:
Total current assets	1
Property, plant and equipment, net	428
Other liabilities:
Total other liabilities	$ 8
[1] As of June 30, 2022, Alliant Energy’s assets of a consolidated VIE that may be used only to settle obligations of that VIE include $1 million of current assets and $428 million of property, plant and equipment, net, and Alliant Energy’s liabilities of that VIE that creditors do not have recourse to include $8 million of other liabilities. Refer to Note 1(b) for additional information. As of June 30, 2022, WPL’s assets of a consolidated VIE that may be used only to settle obligations of that VIE include $1 million of current assets and $428 million of property, plant and equipment, net, and WPL’s liabilities of that VIE that creditors do not have recourse to include $8 million of other liabilities. Refer to Note 1(b) for additional information.

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	480,000,000	480,000,000
Common stock, shares outstanding (in shares)	250,926,232	250,474,529
Shares in deferred compensation trust (in shares)	388,363	383,532
Shares in deferred compensation trust, weighted average cost per share (in dollars per share)	$ 31.72	$ 30.59
IPL [Member]
Common stock, par value (in dollars per share)	$ 2.50	$ 2.50
Common stock, shares authorized (in shares)	24,000,000	24,000,000
Common stock, shares outstanding (in shares)	13,370,788	13,370,788
WPL [Member]
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	18,000,000	18,000,000
Common stock, shares outstanding (in shares)	13,236,601	13,236,601

Condensed Consolidated Statem_2

Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net income	$ 351	$ 320
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	332	329
Deferred tax expense (benefit) and tax credits	12	(42)
Other	(16)	2
Other changes in assets and liabilities:
Accounts receivable	(283)	(265)
Derivative assets	(183)	(68)
Regulatory assets	(116)	4
Accounts payable	95	11
Regulatory liabilities	74	(69)
Derivative liabilities	86	(22)
Deferred income taxes	34	93
Pension and other benefit obligations	(18)	(34)
Other	(68)	(52)
Net cash flows from operating activities	300	207
Cash flows from (used for) investing activities:
Utility business construction and acquisition expenditures	(550)	(426)
Other construction and acquisition expenditures	(43)	(32)
Cash receipts on sold receivables	233	295
Other	(10)	(27)
Net cash flows from (used for) investing activities	(370)	(190)
Cash flows from (used for) financing activities:
Common stock dividends	(215)	(203)
Proceeds from issuance of long-term debt	650	0
Payments to retire long-term debt	(304)	(4)
Net change in commercial paper	(116)	146
Contributions from noncontrolling interest	29	0
Other	6	4
Net cash flows from (used for) financing activities	50	(57)
Net increase (decrease) in cash, cash equivalents and restricted cash	(20)	(40)
Cash, cash equivalents and restricted cash at beginning of period	40	56
Cash, cash equivalents and restricted cash at end of period	20	16
Supplemental cash flows information:
Interest	(146)	(137)
Income taxes, net	(4)	(1)
Significant non-cash investing and financing activities:
Accrued capital expenditures	200	139
Beneficial interest obtained in exchange for securitized accounts receivable	244	154
IPL [Member]
Cash flows from operating activities:
Net income	173	170
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	189	187
Other	(9)	(13)
Other changes in assets and liabilities:
Accounts receivable	(256)	(270)
Derivative assets	(123)	(27)
Regulatory assets	(52)	(14)
Accounts payable	67	1
Regulatory liabilities	53	(36)
Derivative liabilities	63	(11)
Deferred income taxes	24	30
Other	(46)	1
Net cash flows from operating activities	83	18
Cash flows from (used for) investing activities:
Utility business construction and acquisition expenditures	(172)	(191)
Cash receipts on sold receivables	233	295
Other	(1)	(6)
Net cash flows from (used for) investing activities	60	98
Cash flows from (used for) financing activities:
Common stock dividends	(160)	(200)
Capital contributions from parent	0	50
Other	(4)	(5)
Net cash flows from (used for) financing activities	(164)	(155)
Net increase (decrease) in cash, cash equivalents and restricted cash	(21)	(39)
Cash, cash equivalents and restricted cash at beginning of period	34	50
Cash, cash equivalents and restricted cash at end of period	13	11
Supplemental cash flows information:
Interest	(74)	(69)
Income taxes, net	19	27
Significant non-cash investing and financing activities:
Accrued capital expenditures	45	32
Beneficial interest obtained in exchange for securitized accounts receivable	244	154
WPL [Member]
Cash flows from operating activities:
Net income	156	122
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization	139	139
Deferred tax expense (benefit) and tax credits	10	(35)
Other	(6)	10
Other changes in assets and liabilities:
Accounts receivable	(17)	9
Derivative assets	(60)	(41)
Regulatory assets	(65)	17
Accounts payable	38	1
Regulatory liabilities	20	(33)
Derivative liabilities	23	(12)
Deferred income taxes	11	63
Other	(51)	(40)
Net cash flows from operating activities	198	200
Cash flows from (used for) investing activities:
Utility business construction and acquisition expenditures	(378)	(235)
Other	(6)	(18)
Net cash flows from (used for) investing activities	(384)	(253)
Cash flows from (used for) financing activities:
Common stock dividends	(89)	(85)
Capital contributions from parent	265	210
Net change in commercial paper	(14)	(65)
Contributions from noncontrolling interest	29	0
Other	(3)	(7)
Net cash flows from (used for) financing activities	188	53
Net increase (decrease) in cash, cash equivalents and restricted cash	2	0
Cash, cash equivalents and restricted cash at beginning of period	2	3
Cash, cash equivalents and restricted cash at end of period	4	3
Supplemental cash flows information:
Interest	(54)	(52)
Income taxes, net	(31)	(27)
Significant non-cash investing and financing activities:
Accrued capital expenditures	$ 150	$ 104

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Summary Of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2021 Form 10-K . In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2022 are not necessarily indicative of results that may be expected for the year ending December 31, 2022. A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes. Note 1(b) Variable Interest Entities (VIEs) - A portion of WPL’s solar generation projects is financed, and is expected to be financed, with capital from tax equity partners through joint ventures. In 2022, WPL 2022 Solar Holdco, LLC was formed as a joint venture to own and operate project companies responsible for the construction, ownership and operation of various solar generation assets. Members of the joint venture are a WPL subsidiary (the managing member) and a tax equity partner. In June 2022, the WPL subsidiary and the tax equity partner contributed $62 million and $29 million, respectively, to WPL 2022 Solar Holdco, LLC in exchange for membership interests. In June 2022, $88 million of the contributed funds were paid to WPL in exchange for equity interests in the project companies. Once asset construction is complete, the WPL subsidiary and the tax equity partner will make additional cash contributions based on the fair value of the solar generation assets. Earnings, tax attributes, and cash flows from the joint venture will be allocated to both the WPL subsidiary and the tax equity partner in varying percentages over the life of the partnership. Once the tax equity partner has earned its negotiated rate of return and the agreed upon contractual date has been reached, WPL has the option to purchase the remaining interest in the joint venture from the tax equity partner at fair value. Alliant Energy and WPL consolidate this joint venture as it is a VIE in which WPL holds a variable interest, and WPL controls decisions that are significant to the joint venture’s ongoing operations and economic results (i.e., WPL is the primary beneficiary). The joint venture is subject to profit sharing arrangements in which the allocation of the joint venture’s cash distributions and tax benefits to members is based on factors other than members' relative ownership percentages. As a result, WPL utilizes the Hypothetical Liquidation at Book Value (HLBV) method to allocate proceeds to each partner at the balance sheet date based on the liquidation provisions of the related joint venture's operating agreement and to adjust the amount of the VIE's net income attributable to Alliant Energy and WPL, as well as the noncontrolling interest during the period. In each reporting period, the application of HLBV to WPL’s consolidated VIE results in a difference between the amount of profit from the consolidated joint venture and the amount included in WPL’s regulated rates. WPL is subject to GAAP provisions for regulated operations and recognizes a regulatory liability or regulatory asset for amounts representing the timing difference between WPL’s profit earned from the joint venture and the amount included in regulated rates for recovery of its solar generation projects. The amounts recorded in income will ultimately reflect the amount allowed in regulated rates to recover WPL’s investments over the useful life of the solar projects. Refer to Note 6 for discussion of a noncontrolling interest associated with the joint venture.
IPL [Member]
Summary Of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2021 Form 10-K . In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2022 are not necessarily indicative of results that may be expected for the year ending December 31, 2022. A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.
WPL [Member]
Summary Of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2021 Form 10-K . In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the six months ended June 30, 2022 are not necessarily indicative of results that may be expected for the year ending December 31, 2022. A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes. Note 1(b) Variable Interest Entities (VIEs) - A portion of WPL’s solar generation projects is financed, and is expected to be financed, with capital from tax equity partners through joint ventures. In 2022, WPL 2022 Solar Holdco, LLC was formed as a joint venture to own and operate project companies responsible for the construction, ownership and operation of various solar generation assets. Members of the joint venture are a WPL subsidiary (the managing member) and a tax equity partner. In June 2022, the WPL subsidiary and the tax equity partner contributed $62 million and $29 million, respectively, to WPL 2022 Solar Holdco, LLC in exchange for membership interests. In June 2022, $88 million of the contributed funds were paid to WPL in exchange for equity interests in the project companies. Once asset construction is complete, the WPL subsidiary and the tax equity partner will make additional cash contributions based on the fair value of the solar generation assets. Earnings, tax attributes, and cash flows from the joint venture will be allocated to both the WPL subsidiary and the tax equity partner in varying percentages over the life of the partnership. Once the tax equity partner has earned its negotiated rate of return and the agreed upon contractual date has been reached, WPL has the option to purchase the remaining interest in the joint venture from the tax equity partner at fair value. Alliant Energy and WPL consolidate this joint venture as it is a VIE in which WPL holds a variable interest, and WPL controls decisions that are significant to the joint venture’s ongoing operations and economic results (i.e., WPL is the primary beneficiary). The joint venture is subject to profit sharing arrangements in which the allocation of the joint venture’s cash distributions and tax benefits to members is based on factors other than members' relative ownership percentages. As a result, WPL utilizes the Hypothetical Liquidation at Book Value (HLBV) method to allocate proceeds to each partner at the balance sheet date based on the liquidation provisions of the related joint venture's operating agreement and to adjust the amount of the VIE's net income attributable to Alliant Energy and WPL, as well as the noncontrolling interest during the period. In each reporting period, the application of HLBV to WPL’s consolidated VIE results in a difference between the amount of profit from the consolidated joint venture and the amount included in WPL’s regulated rates. WPL is subject to GAAP provisions for regulated operations and recognizes a regulatory liability or regulatory asset for amounts representing the timing difference between WPL’s profit earned from the joint venture and the amount included in regulated rates for recovery of its solar generation projects. The amounts recorded in income will ultimately reflect the amount allowed in regulated rates to recover WPL’s investments over the useful life of the solar projects. Refer to Note 6 for discussion of a noncontrolling interest associated with the joint venture.

Regulatory Matters

Regulatory Matters	6 Months Ended
	Jun. 30, 2022
Public Utilities, General Disclosures [Line Items]
Regulatory Matters	REGULATORY MATTERS Regulatory Assets and Regulatory Liabilities - Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $954 $934 $903 $884 $51 $50 Pension and OPEB costs 445 462 220 228 225 234 Asset retirement obligations 140 128 99 89 41 39 Derivatives 101 8 69 4 32 4 Commodity cost recovery 88 42 2 2 86 40 Assets retired early 82 92 61 66 21 26 IPL’s DAEC PPA amendment 78 90 78 90 — — WPL’s Western Wisconsin gas distribution expansion investments 50 52 — — 50 52 Other 113 132 58 80 55 52 $2,051 $1,940 $1,490 $1,443 $561 $497 Derivatives - Refer to Note 1 1 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the three and six months ended June 30, 2022, which result in comparable changes to regulatory assets/liabilities on the balance sheets. Commodity cost recovery - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. During the six months ended June 30, 2022, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $40 million deferral of higher than expected fuel-related costs as of June 30, 2022. Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $573 $585 $308 $312 $265 $273 Cost of removal obligations 396 384 258 252 138 132 Derivatives 288 166 153 77 135 89 WPL’s West Riverside liquidated damages 34 36 — — 34 36 Electric transmission cost recovery 31 51 11 27 20 24 Other 41 49 21 23 20 26 $1,363 $1,271 $751 $691 $612 $580
IPL [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Matters	REGULATORY MATTERS Regulatory Assets and Regulatory Liabilities - Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $954 $934 $903 $884 $51 $50 Pension and OPEB costs 445 462 220 228 225 234 Asset retirement obligations 140 128 99 89 41 39 Derivatives 101 8 69 4 32 4 Commodity cost recovery 88 42 2 2 86 40 Assets retired early 82 92 61 66 21 26 IPL’s DAEC PPA amendment 78 90 78 90 — — WPL’s Western Wisconsin gas distribution expansion investments 50 52 — — 50 52 Other 113 132 58 80 55 52 $2,051 $1,940 $1,490 $1,443 $561 $497 Derivatives - Refer to Note 1 1 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the three and six months ended June 30, 2022, which result in comparable changes to regulatory assets/liabilities on the balance sheets. Commodity cost recovery - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. During the six months ended June 30, 2022, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $40 million deferral of higher than expected fuel-related costs as of June 30, 2022. Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $573 $585 $308 $312 $265 $273 Cost of removal obligations 396 384 258 252 138 132 Derivatives 288 166 153 77 135 89 WPL’s West Riverside liquidated damages 34 36 — — 34 36 Electric transmission cost recovery 31 51 11 27 20 24 Other 41 49 21 23 20 26 $1,363 $1,271 $751 $691 $612 $580
WPL [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Matters	REGULATORY MATTERS Regulatory Assets and Regulatory Liabilities - Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $954 $934 $903 $884 $51 $50 Pension and OPEB costs 445 462 220 228 225 234 Asset retirement obligations 140 128 99 89 41 39 Derivatives 101 8 69 4 32 4 Commodity cost recovery 88 42 2 2 86 40 Assets retired early 82 92 61 66 21 26 IPL’s DAEC PPA amendment 78 90 78 90 — — WPL’s Western Wisconsin gas distribution expansion investments 50 52 — — 50 52 Other 113 132 58 80 55 52 $2,051 $1,940 $1,490 $1,443 $561 $497 Derivatives - Refer to Note 1 1 for discussion of changes in Alliant Energy’s, IPL’s and WPL’s derivative liabilities/assets during the three and six months ended June 30, 2022, which result in comparable changes to regulatory assets/liabilities on the balance sheets. Commodity cost recovery - The cost recovery mechanism for WPL’s retail electric customers is based on forecasts of certain fuel-related costs expected to be incurred during forward-looking test periods and fuel monitoring ranges determined by the PSCW during each retail electric rate proceeding or in a separate fuel cost plan approval proceeding. During the six months ended June 30, 2022, WPL’s actual fuel-related costs fell outside these fuel monitoring ranges, resulting in a $40 million deferral of higher than expected fuel-related costs as of June 30, 2022. Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $573 $585 $308 $312 $265 $273 Cost of removal obligations 396 384 258 252 138 132 Derivatives 288 166 153 77 135 89 WPL’s West Riverside liquidated damages 34 36 — — 34 36 Electric transmission cost recovery 31 51 11 27 20 24 Other 41 49 21 23 20 26 $1,363 $1,271 $751 $691 $612 $580

Property, Plant and Equipment

Property, Plant and Equipment	6 Months Ended
	Jun. 30, 2022
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENTIn June 2022, WPL announced revised expected timing for the retirements of its remaining coal-fired EGUs in order to help manage regional capacity and changing generation requirements across the MISO region. WPL currently expects to retire the Edgewater Generating Station (414 MW) by June 1, 2025, and Columbia Units 1 and 2 by June 1, 2026 (595 MW in aggregate). In addition, IPL currently expects to retire the coal-fired Lansing Generating Station (275 MW) in the first half of 2023. Alliant Energy, IPL and WPL are working with MISO, state regulatory commissions and other regulatory agencies, as required, to determine the timing of these actions, which are subject to change depending on operational, regulatory, market and other factors.
IPL [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENTIn June 2022, WPL announced revised expected timing for the retirements of its remaining coal-fired EGUs in order to help manage regional capacity and changing generation requirements across the MISO region. WPL currently expects to retire the Edgewater Generating Station (414 MW) by June 1, 2025, and Columbia Units 1 and 2 by June 1, 2026 (595 MW in aggregate). In addition, IPL currently expects to retire the coal-fired Lansing Generating Station (275 MW) in the first half of 2023. Alliant Energy, IPL and WPL are working with MISO, state regulatory commissions and other regulatory agencies, as required, to determine the timing of these actions, which are subject to change depending on operational, regulatory, market and other factors.
WPL [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENTIn June 2022, WPL announced revised expected timing for the retirements of its remaining coal-fired EGUs in order to help manage regional capacity and changing generation requirements across the MISO region. WPL currently expects to retire the Edgewater Generating Station (414 MW) by June 1, 2025, and Columbia Units 1 and 2 by June 1, 2026 (595 MW in aggregate). In addition, IPL currently expects to retire the coal-fired Lansing Generating Station (275 MW) in the first half of 2023. Alliant Energy, IPL and WPL are working with MISO, state regulatory commissions and other regulatory agencies, as required, to determine the timing of these actions, which are subject to change depending on operational, regulatory, market and other factors.

Receivables

Receivables	6 Months Ended
	Jun. 30, 2022
Receivables [Line Items]
Receivables	RECEIVABLES Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (Receivables Agreement) whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of June 30, 2022, IPL had $95 million of available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 Maximum outstanding aggregate cash proceeds $66 $110 $66 $110 Average outstanding aggregate cash proceeds 18 61 11 46 The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions): June 30, 2022 December 31, 2021 Customer accounts receivable $150 $125 Unbilled utility revenues 119 104 Receivables sold to third party 269 229 Less: cash proceeds 15 1 Deferred proceeds 254 228 Less: allowance for expected credit losses 10 14 Fair value of deferred proceeds $244 $214 As of June 30, 2022, outstanding receivables past due under the Receivables Agreement were $20 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 Collections $500 $453 $1,061 $982 Write-offs, net of recoveries 1 1 3 3
IPL [Member]
Receivables [Line Items]
Receivables	RECEIVABLES Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (Receivables Agreement) whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of June 30, 2022, IPL had $95 million of available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 Maximum outstanding aggregate cash proceeds $66 $110 $66 $110 Average outstanding aggregate cash proceeds 18 61 11 46 The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions): June 30, 2022 December 31, 2021 Customer accounts receivable $150 $125 Unbilled utility revenues 119 104 Receivables sold to third party 269 229 Less: cash proceeds 15 1 Deferred proceeds 254 228 Less: allowance for expected credit losses 10 14 Fair value of deferred proceeds $244 $214 As of June 30, 2022, outstanding receivables past due under the Receivables Agreement were $20 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 Collections $500 $453 $1,061 $982 Write-offs, net of recoveries 1 1 3 3

Investments

Investments	6 Months Ended
	Jun. 30, 2022
Schedule of Equity Method Investments [Line Items]
Investments	INVESTMENTS Unconsolidated Equity Investments - Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three and six months ended June 30 was as follows (in millions): Three Months Six Months 2022 2021 2022 2021 ATC Holdings ($11) ($11) ($23) ($22) Other (5) (8) (9) (12) ($16) ($19) ($32) ($34)

Common Equity

Common Equity	6 Months Ended
	Jun. 30, 2022
Common Equity [Line Items]
Common Equity	COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows: Shares outstanding, January 1, 2022 250,474,529 Shareowner Direct Plan 228,935 Equity-based compensation plans 222,768 Shares outstanding, June 30, 2022 250,926,232 Noncontrolling Interest - In the second quarter of 2022, WPL and the tax equity partner contributed to the joint venture associated with certain WPL solar generation projects. Earnings, tax attributes and cash flows from the joint venture will be allocated to both the WPL subsidiary and the tax equity partner in varying percentages by category and over the life of the partnership. The tax equity partner's contributions, net of these allocations, is represented as a noncontrolling interest within total equity on Alliant Energy’s and WPL’s balance sheets. Refer to Note 1(b) for additional information. Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions): Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $3 $2,750 $3,336 $— ($12) $— $6,077 Net income attributable to Alliant Energy common shareowners 159 159 Common stock dividends ($0.4275 per share) (108) (108) Shareowner Direct Plan issuances 6 6 Equity-based compensation plans and other 3 3 Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $3 $2,712 $3,063 ($1) ($11) $200 $5,966 Net income attributable to Alliant Energy common shareowners 144 144 Common stock dividends ($0.4025 per share) (101) (101) Shareowner Direct Plan issuances 7 7 Equity-based compensation plans and other 3 3 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $3 $2,749 $3,250 $— ($12) $— $5,990 Net income attributable to Alliant Energy common shareowners 351 351 Common stock dividends ($0.855 per share) (215) (215) Shareowner Direct Plan issuances 13 13 Equity-based compensation plans and other (3) 1 (2) Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $2 $2,704 $2,994 ($1) ($11) $200 $5,888 Net income attributable to Alliant Energy common shareowners 315 315 Common stock dividends ($0.805 per share) (203) (203) Shareowner Direct Plan issuances 1 14 15 Equity-based compensation plans and other 4 4 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $33 $2,807 $935 $— $3,775 Net income available for common stock 87 87 Common stock dividends (80) (80) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $33 $2,752 $957 $200 $3,942 Net income available for common stock 86 86 Common stock dividends (99) (99) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $33 $2,807 $929 $— $3,769 Net income available for common stock 173 173 Common stock dividends (160) (160) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $33 $2,752 $979 $200 $3,964 Net income available for common stock 165 165 Common stock dividends (200) (200) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $66 $1,884 $1,101 $— $3,051 Net income 63 63 Common stock dividends (44) (44) Capital contributions from parent 85 85 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $66 $1,584 $995 $— $2,645 Net income 38 38 Common stock dividends (43) (43) Capital contributions from parent 85 85 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $66 $1,704 $1,053 $— $2,823 Net income 156 156 Common stock dividends (89) (89) Capital contributions from parent 265 265 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $66 $1,459 $953 $— $2,478 Net income 122 122 Common stock dividends (85) (85) Capital contributions from parent 210 210 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725
IPL [Member]
Common Equity [Line Items]
Common Equity	COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows: Shares outstanding, January 1, 2022 250,474,529 Shareowner Direct Plan 228,935 Equity-based compensation plans 222,768 Shares outstanding, June 30, 2022 250,926,232 Noncontrolling Interest - In the second quarter of 2022, WPL and the tax equity partner contributed to the joint venture associated with certain WPL solar generation projects. Earnings, tax attributes and cash flows from the joint venture will be allocated to both the WPL subsidiary and the tax equity partner in varying percentages by category and over the life of the partnership. The tax equity partner's contributions, net of these allocations, is represented as a noncontrolling interest within total equity on Alliant Energy’s and WPL’s balance sheets. Refer to Note 1(b) for additional information. Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions): Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $3 $2,750 $3,336 $— ($12) $— $6,077 Net income attributable to Alliant Energy common shareowners 159 159 Common stock dividends ($0.4275 per share) (108) (108) Shareowner Direct Plan issuances 6 6 Equity-based compensation plans and other 3 3 Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $3 $2,712 $3,063 ($1) ($11) $200 $5,966 Net income attributable to Alliant Energy common shareowners 144 144 Common stock dividends ($0.4025 per share) (101) (101) Shareowner Direct Plan issuances 7 7 Equity-based compensation plans and other 3 3 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $3 $2,749 $3,250 $— ($12) $— $5,990 Net income attributable to Alliant Energy common shareowners 351 351 Common stock dividends ($0.855 per share) (215) (215) Shareowner Direct Plan issuances 13 13 Equity-based compensation plans and other (3) 1 (2) Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $2 $2,704 $2,994 ($1) ($11) $200 $5,888 Net income attributable to Alliant Energy common shareowners 315 315 Common stock dividends ($0.805 per share) (203) (203) Shareowner Direct Plan issuances 1 14 15 Equity-based compensation plans and other 4 4 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $33 $2,807 $935 $— $3,775 Net income available for common stock 87 87 Common stock dividends (80) (80) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $33 $2,752 $957 $200 $3,942 Net income available for common stock 86 86 Common stock dividends (99) (99) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $33 $2,807 $929 $— $3,769 Net income available for common stock 173 173 Common stock dividends (160) (160) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $33 $2,752 $979 $200 $3,964 Net income available for common stock 165 165 Common stock dividends (200) (200) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $66 $1,884 $1,101 $— $3,051 Net income 63 63 Common stock dividends (44) (44) Capital contributions from parent 85 85 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $66 $1,584 $995 $— $2,645 Net income 38 38 Common stock dividends (43) (43) Capital contributions from parent 85 85 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $66 $1,704 $1,053 $— $2,823 Net income 156 156 Common stock dividends (89) (89) Capital contributions from parent 265 265 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $66 $1,459 $953 $— $2,478 Net income 122 122 Common stock dividends (85) (85) Capital contributions from parent 210 210 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725
WPL [Member]
Common Equity [Line Items]
Common Equity	COMMON EQUITY Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows: Shares outstanding, January 1, 2022 250,474,529 Shareowner Direct Plan 228,935 Equity-based compensation plans 222,768 Shares outstanding, June 30, 2022 250,926,232 Noncontrolling Interest - In the second quarter of 2022, WPL and the tax equity partner contributed to the joint venture associated with certain WPL solar generation projects. Earnings, tax attributes and cash flows from the joint venture will be allocated to both the WPL subsidiary and the tax equity partner in varying percentages by category and over the life of the partnership. The tax equity partner's contributions, net of these allocations, is represented as a noncontrolling interest within total equity on Alliant Energy’s and WPL’s balance sheets. Refer to Note 1(b) for additional information. Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions): Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $3 $2,750 $3,336 $— ($12) $— $6,077 Net income attributable to Alliant Energy common shareowners 159 159 Common stock dividends ($0.4275 per share) (108) (108) Shareowner Direct Plan issuances 6 6 Equity-based compensation plans and other 3 3 Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $3 $2,712 $3,063 ($1) ($11) $200 $5,966 Net income attributable to Alliant Energy common shareowners 144 144 Common stock dividends ($0.4025 per share) (101) (101) Shareowner Direct Plan issuances 7 7 Equity-based compensation plans and other 3 3 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $3 $2,749 $3,250 $— ($12) $— $5,990 Net income attributable to Alliant Energy common shareowners 351 351 Common stock dividends ($0.855 per share) (215) (215) Shareowner Direct Plan issuances 13 13 Equity-based compensation plans and other (3) 1 (2) Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $2 $2,704 $2,994 ($1) ($11) $200 $5,888 Net income attributable to Alliant Energy common shareowners 315 315 Common stock dividends ($0.805 per share) (203) (203) Shareowner Direct Plan issuances 1 14 15 Equity-based compensation plans and other 4 4 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $33 $2,807 $935 $— $3,775 Net income available for common stock 87 87 Common stock dividends (80) (80) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $33 $2,752 $957 $200 $3,942 Net income available for common stock 86 86 Common stock dividends (99) (99) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $33 $2,807 $929 $— $3,769 Net income available for common stock 173 173 Common stock dividends (160) (160) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $33 $2,752 $979 $200 $3,964 Net income available for common stock 165 165 Common stock dividends (200) (200) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $66 $1,884 $1,101 $— $3,051 Net income 63 63 Common stock dividends (44) (44) Capital contributions from parent 85 85 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $66 $1,584 $995 $— $2,645 Net income 38 38 Common stock dividends (43) (43) Capital contributions from parent 85 85 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $66 $1,704 $1,053 $— $2,823 Net income 156 156 Common stock dividends (89) (89) Capital contributions from parent 265 265 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $66 $1,459 $953 $— $2,478 Net income 122 122 Common stock dividends (85) (85) Capital contributions from parent 210 210 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725

Debt

Debt	6 Months Ended
	Jun. 30, 2022
Debt [Line Items]
Debt	DEBT NOTE 7(a) Short-term Debt - Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions): June 30, 2022 Alliant Energy IPL WPL Amount outstanding $399 $— $222 Weighted average interest rates 1.8% N/A 1.7% Available credit facility capacity $601 $250 $78 Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Maximum amount outstanding (based on daily outstanding balances) $441 $571 $— $19 $222 $232 Average amount outstanding (based on daily outstanding balances) $337 $452 $— $1 $166 $177 Weighted average interest rates 1.0% 0.2% —% 0.2% 0.9% 0.1% Six Months Ended June 30 Maximum amount outstanding (based on daily outstanding balances) $577 $578 $— $19 $252 $275 Average amount outstanding (based on daily outstanding balances) $390 $438 $— $— $185 $183 Weighted average interest rates 0.6% 0.2% —% 0.2% 0.5% 0.1% NOTE 7(b) Long-term Debt - In February 2022, AEF issued $350 million of 3.6% senior notes due 2032. The net proceeds from the issuance were used to reduce Alliant Energy’s outstanding commercial paper and for general corporate purposes. In March 2022, AEF entered into a $300 million variable rate (2% as of June 30, 2022) term loan credit agreement (with Alliant Energy as guarantor), which expires in March 2024, and used the borrowings under this agreement to retire its $300 million variable rate term loan credit agreement that expired in March 2022.
IPL [Member]
Debt [Line Items]
Debt	DEBT NOTE 7(a) Short-term Debt - Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions): June 30, 2022 Alliant Energy IPL WPL Amount outstanding $399 $— $222 Weighted average interest rates 1.8% N/A 1.7% Available credit facility capacity $601 $250 $78 Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Maximum amount outstanding (based on daily outstanding balances) $441 $571 $— $19 $222 $232 Average amount outstanding (based on daily outstanding balances) $337 $452 $— $1 $166 $177 Weighted average interest rates 1.0% 0.2% —% 0.2% 0.9% 0.1% Six Months Ended June 30 Maximum amount outstanding (based on daily outstanding balances) $577 $578 $— $19 $252 $275 Average amount outstanding (based on daily outstanding balances) $390 $438 $— $— $185 $183 Weighted average interest rates 0.6% 0.2% —% 0.2% 0.5% 0.1%
WPL [Member]
Debt [Line Items]
Debt	DEBT NOTE 7(a) Short-term Debt - Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions): June 30, 2022 Alliant Energy IPL WPL Amount outstanding $399 $— $222 Weighted average interest rates 1.8% N/A 1.7% Available credit facility capacity $601 $250 $78 Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Maximum amount outstanding (based on daily outstanding balances) $441 $571 $— $19 $222 $232 Average amount outstanding (based on daily outstanding balances) $337 $452 $— $1 $166 $177 Weighted average interest rates 1.0% 0.2% —% 0.2% 0.9% 0.1% Six Months Ended June 30 Maximum amount outstanding (based on daily outstanding balances) $577 $578 $— $19 $252 $275 Average amount outstanding (based on daily outstanding balances) $390 $438 $— $— $185 $183 Weighted average interest rates 0.6% 0.2% —% 0.2% 0.5% 0.1%

Revenues

Revenues	6 Months Ended
	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	REVENUES Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $289 $258 $158 $142 $131 $116 Retail - commercial 196 175 127 115 69 60 Retail - industrial 244 210 136 116 108 94 Wholesale 54 47 16 15 38 32 Bulk power and other 29 27 5 14 24 13 Total Electric Utility 812 717 442 402 370 315 Gas Utility: Retail - residential 51 39 28 24 23 15 Retail - commercial 27 19 14 12 13 7 Retail - industrial 3 3 2 2 1 1 Transportation/other 13 8 8 5 5 3 Total Gas Utility 94 69 52 43 42 26 Other Utility: Steam 11 9 11 9 — — Other utility 2 1 1 1 1 — Total Other Utility 13 10 12 10 1 — Non-Utility and Other: Travero and other 24 21 — — — — Total Non-Utility and Other 24 21 — — — — Total revenues $943 $817 $506 $455 $413 $341 Alliant Energy IPL WPL Six Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $581 $520 $308 $281 $273 $239 Retail - commercial 386 347 246 225 140 122 Retail - industrial 453 412 246 228 207 184 Wholesale 101 87 31 26 70 61 Bulk power and other 65 52 12 28 53 24 Total Electric Utility 1,586 1,418 843 788 743 630 Gas Utility: Retail - residential 210 138 113 76 97 62 Retail - commercial 109 72 54 39 55 33 Retail - industrial 11 8 7 5 4 3 Transportation/other 26 21 17 14 9 7 Total Gas Utility 356 239 191 134 165 105 Other Utility: Steam 20 18 20 18 — — Other utility 3 5 2 4 1 1 Total Other Utility 23 23 22 22 1 1 Non-Utility and Other: Travero and other 47 38 — — — — Total Non-Utility and Other 47 38 — — — — Total revenues $2,012 $1,718 $1,056 $944 $909 $736
IPL [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	REVENUES Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $289 $258 $158 $142 $131 $116 Retail - commercial 196 175 127 115 69 60 Retail - industrial 244 210 136 116 108 94 Wholesale 54 47 16 15 38 32 Bulk power and other 29 27 5 14 24 13 Total Electric Utility 812 717 442 402 370 315 Gas Utility: Retail - residential 51 39 28 24 23 15 Retail - commercial 27 19 14 12 13 7 Retail - industrial 3 3 2 2 1 1 Transportation/other 13 8 8 5 5 3 Total Gas Utility 94 69 52 43 42 26 Other Utility: Steam 11 9 11 9 — — Other utility 2 1 1 1 1 — Total Other Utility 13 10 12 10 1 — Non-Utility and Other: Travero and other 24 21 — — — — Total Non-Utility and Other 24 21 — — — — Total revenues $943 $817 $506 $455 $413 $341 Alliant Energy IPL WPL Six Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $581 $520 $308 $281 $273 $239 Retail - commercial 386 347 246 225 140 122 Retail - industrial 453 412 246 228 207 184 Wholesale 101 87 31 26 70 61 Bulk power and other 65 52 12 28 53 24 Total Electric Utility 1,586 1,418 843 788 743 630 Gas Utility: Retail - residential 210 138 113 76 97 62 Retail - commercial 109 72 54 39 55 33 Retail - industrial 11 8 7 5 4 3 Transportation/other 26 21 17 14 9 7 Total Gas Utility 356 239 191 134 165 105 Other Utility: Steam 20 18 20 18 — — Other utility 3 5 2 4 1 1 Total Other Utility 23 23 22 22 1 1 Non-Utility and Other: Travero and other 47 38 — — — — Total Non-Utility and Other 47 38 — — — — Total revenues $2,012 $1,718 $1,056 $944 $909 $736
WPL [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	REVENUES Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $289 $258 $158 $142 $131 $116 Retail - commercial 196 175 127 115 69 60 Retail - industrial 244 210 136 116 108 94 Wholesale 54 47 16 15 38 32 Bulk power and other 29 27 5 14 24 13 Total Electric Utility 812 717 442 402 370 315 Gas Utility: Retail - residential 51 39 28 24 23 15 Retail - commercial 27 19 14 12 13 7 Retail - industrial 3 3 2 2 1 1 Transportation/other 13 8 8 5 5 3 Total Gas Utility 94 69 52 43 42 26 Other Utility: Steam 11 9 11 9 — — Other utility 2 1 1 1 1 — Total Other Utility 13 10 12 10 1 — Non-Utility and Other: Travero and other 24 21 — — — — Total Non-Utility and Other 24 21 — — — — Total revenues $943 $817 $506 $455 $413 $341 Alliant Energy IPL WPL Six Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $581 $520 $308 $281 $273 $239 Retail - commercial 386 347 246 225 140 122 Retail - industrial 453 412 246 228 207 184 Wholesale 101 87 31 26 70 61 Bulk power and other 65 52 12 28 53 24 Total Electric Utility 1,586 1,418 843 788 743 630 Gas Utility: Retail - residential 210 138 113 76 97 62 Retail - commercial 109 72 54 39 55 33 Retail - industrial 11 8 7 5 4 3 Transportation/other 26 21 17 14 9 7 Total Gas Utility 356 239 191 134 165 105 Other Utility: Steam 20 18 20 18 — — Other utility 3 5 2 4 1 1 Total Other Utility 23 23 22 22 1 1 Non-Utility and Other: Travero and other 47 38 — — — — Total Non-Utility and Other 47 38 — — — — Total revenues $2,012 $1,718 $1,056 $944 $909 $736

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2022
Income Taxes [Line Items]
Income Taxes	INCOME TAXES Income Tax Rates - Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. The increases in Alliant Energy’s and WPL’s overall effective income tax rates for the three and six months ended June 30, 2022 compared to the same periods in 2021 were primarily due to decreased amortization of excess deferred taxes primarily at WPL. Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Overall income tax rate 2% (13%) 3% (16%) (16%) (13%) (15%) (15%) 18% (23%) 18% (27%) Deferred Tax Assets and Liabilities - Carryforwards - At June 30, 2022, carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2037 $41 $38 $— State net operating losses 2022-2042 556 10 2 Federal tax credits 2022-2042 620 396 201 Iowa Tax Reform - In March 2022, Iowa tax reform was enacted, which would reduce the current 9.8% Iowa corporate income tax rate beginning in 2023 if certain state income tax revenue triggers are satisfied. Annually, and by each November 1, the Iowa Department of Revenue will establish corporate income tax rates for the next tax year based on net corporate income tax receipts for the prior tax year. These corporate income tax rate reductions are currently expected to occur over a period of several years, with a target corporate income tax rate of 5.5%. Alliant Energy is currently unable to predict with certainty the timing or amount of any rate reductions. The majority of any reduction in income tax expense as a result of the lower Iowa corporate income tax rate is currently expected to reduce rates for IPL’s customers. In addition, after the 2023 corporate income tax rate is known in the fourth quarter of 2022, Alliant Energy currently expects to record a charge related to the remeasurement of accumulated deferred income tax assets at its non-utility businesses.
IPL [Member]
Income Taxes [Line Items]
Income Taxes	INCOME TAXES Income Tax Rates - Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. The increases in Alliant Energy’s and WPL’s overall effective income tax rates for the three and six months ended June 30, 2022 compared to the same periods in 2021 were primarily due to decreased amortization of excess deferred taxes primarily at WPL. Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Overall income tax rate 2% (13%) 3% (16%) (16%) (13%) (15%) (15%) 18% (23%) 18% (27%) Deferred Tax Assets and Liabilities - Carryforwards - At June 30, 2022, carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2037 $41 $38 $— State net operating losses 2022-2042 556 10 2 Federal tax credits 2022-2042 620 396 201 Iowa Tax Reform - In March 2022, Iowa tax reform was enacted, which would reduce the current 9.8% Iowa corporate income tax rate beginning in 2023 if certain state income tax revenue triggers are satisfied. Annually, and by each November 1, the Iowa Department of Revenue will establish corporate income tax rates for the next tax year based on net corporate income tax receipts for the prior tax year. These corporate income tax rate reductions are currently expected to occur over a period of several years, with a target corporate income tax rate of 5.5%. Alliant Energy is currently unable to predict with certainty the timing or amount of any rate reductions. The majority of any reduction in income tax expense as a result of the lower Iowa corporate income tax rate is currently expected to reduce rates for IPL’s customers. In addition, after the 2023 corporate income tax rate is known in the fourth quarter of 2022, Alliant Energy currently expects to record a charge related to the remeasurement of accumulated deferred income tax assets at its non-utility businesses.
WPL [Member]
Income Taxes [Line Items]
Income Taxes	INCOME TAXES Income Tax Rates - Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. The increases in Alliant Energy’s and WPL’s overall effective income tax rates for the three and six months ended June 30, 2022 compared to the same periods in 2021 were primarily due to decreased amortization of excess deferred taxes primarily at WPL. Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Overall income tax rate 2% (13%) 3% (16%) (16%) (13%) (15%) (15%) 18% (23%) 18% (27%) Deferred Tax Assets and Liabilities - Carryforwards - At June 30, 2022, carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2037 $41 $38 $— State net operating losses 2022-2042 556 10 2 Federal tax credits 2022-2042 620 396 201 Iowa Tax Reform - In March 2022, Iowa tax reform was enacted, which would reduce the current 9.8% Iowa corporate income tax rate beginning in 2023 if certain state income tax revenue triggers are satisfied. Annually, and by each November 1, the Iowa Department of Revenue will establish corporate income tax rates for the next tax year based on net corporate income tax receipts for the prior tax year. These corporate income tax rate reductions are currently expected to occur over a period of several years, with a target corporate income tax rate of 5.5%. Alliant Energy is currently unable to predict with certainty the timing or amount of any rate reductions. The majority of any reduction in income tax expense as a result of the lower Iowa corporate income tax rate is currently expected to reduce rates for IPL’s customers. In addition, after the 2023 corporate income tax rate is known in the fourth quarter of 2022, Alliant Energy currently expects to record a charge related to the remeasurement of accumulated deferred income tax assets at its non-utility businesses.

Benefit Plans

Benefit Plans	6 Months Ended
	Jun. 30, 2022
Benefit Plans	BENEFIT PLANS NOTE 10(a) Pension and OPEB Plans - Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans. Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months Alliant Energy 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $2 $3 $4 $6 $1 $1 $2 $2 Interest cost 9 9 18 17 2 1 3 2 Expected return on plan assets (17) (17) (34) (34) (2) (1) (3) (2) Amortization of actuarial loss 8 9 16 19 — 1 1 2 $2 $4 $4 $8 $1 $2 $3 $4 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months IPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $2 $3 $4 $1 $1 $1 $1 Interest cost 4 4 8 8 — — 1 1 Expected return on plan assets (8) (8) (16) (16) (1) (1) (2) (2) Amortization of actuarial loss 4 4 7 8 — 1 — 1 $1 $2 $2 $4 $— $1 $— $1 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months WPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $1 $2 $2 $— $— $— $— Interest cost 4 4 8 8 — 1 1 1 Expected return on plan assets (8) (7) (16) (15) — — — — Amortization of actuarial loss 4 4 8 9 1 — 1 1 $1 $2 $2 $4 $1 $1 $2 $2 NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Compensation expense $3 $2 $7 $5 $1 $2 $4 $3 $1 $1 $3 $2 Income tax benefits 1 1 2 2 — 1 1 1 — 1 1 1 As of June 30, 2022, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $11 million, $6 million and $5 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years. For the six months ended June 30, 2022, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. Weighted Average Grants Grant Date Fair Value Performance shares 73,762 $54.45 Performance restricted stock units 84,277 56.97 Restricted stock units 76,876 56.86 As of June 30, 2022, 261,301 shares were included in the calculation of diluted EPS related to the nonvested equity awards.
IPL [Member]
Benefit Plans	BENEFIT PLANS NOTE 10(a) Pension and OPEB Plans - Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans. Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months Alliant Energy 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $2 $3 $4 $6 $1 $1 $2 $2 Interest cost 9 9 18 17 2 1 3 2 Expected return on plan assets (17) (17) (34) (34) (2) (1) (3) (2) Amortization of actuarial loss 8 9 16 19 — 1 1 2 $2 $4 $4 $8 $1 $2 $3 $4 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months IPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $2 $3 $4 $1 $1 $1 $1 Interest cost 4 4 8 8 — — 1 1 Expected return on plan assets (8) (8) (16) (16) (1) (1) (2) (2) Amortization of actuarial loss 4 4 7 8 — 1 — 1 $1 $2 $2 $4 $— $1 $— $1 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months WPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $1 $2 $2 $— $— $— $— Interest cost 4 4 8 8 — 1 1 1 Expected return on plan assets (8) (7) (16) (15) — — — — Amortization of actuarial loss 4 4 8 9 1 — 1 1 $1 $2 $2 $4 $1 $1 $2 $2 NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Compensation expense $3 $2 $7 $5 $1 $2 $4 $3 $1 $1 $3 $2 Income tax benefits 1 1 2 2 — 1 1 1 — 1 1 1 As of June 30, 2022, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $11 million, $6 million and $5 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years. For the six months ended June 30, 2022, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. Weighted Average Grants Grant Date Fair Value Performance shares 73,762 $54.45 Performance restricted stock units 84,277 56.97 Restricted stock units 76,876 56.86 As of June 30, 2022, 261,301 shares were included in the calculation of diluted EPS related to the nonvested equity awards.
WPL [Member]
Benefit Plans	BENEFIT PLANS NOTE 10(a) Pension and OPEB Plans - Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans. Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months Alliant Energy 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $2 $3 $4 $6 $1 $1 $2 $2 Interest cost 9 9 18 17 2 1 3 2 Expected return on plan assets (17) (17) (34) (34) (2) (1) (3) (2) Amortization of actuarial loss 8 9 16 19 — 1 1 2 $2 $4 $4 $8 $1 $2 $3 $4 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months IPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $2 $3 $4 $1 $1 $1 $1 Interest cost 4 4 8 8 — — 1 1 Expected return on plan assets (8) (8) (16) (16) (1) (1) (2) (2) Amortization of actuarial loss 4 4 7 8 — 1 — 1 $1 $2 $2 $4 $— $1 $— $1 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months WPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $1 $2 $2 $— $— $— $— Interest cost 4 4 8 8 — 1 1 1 Expected return on plan assets (8) (7) (16) (15) — — — — Amortization of actuarial loss 4 4 8 9 1 — 1 1 $1 $2 $2 $4 $1 $1 $2 $2 NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Compensation expense $3 $2 $7 $5 $1 $2 $4 $3 $1 $1 $3 $2 Income tax benefits 1 1 2 2 — 1 1 1 — 1 1 1 As of June 30, 2022, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $11 million, $6 million and $5 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years. For the six months ended June 30, 2022, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. Weighted Average Grants Grant Date Fair Value Performance shares 73,762 $54.45 Performance restricted stock units 84,277 56.97 Restricted stock units 76,876 56.86 As of June 30, 2022, 261,301 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

Derivative Instruments

Derivative Instruments	6 Months Ended
	Jun. 30, 2022
Derivative Instruments [Line Items]
Derivative Instruments	DERIVATIVE INSTRUMENTS Commodity Derivatives - Notional Amounts - As of June 30, 2022, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 818 2022,2024 20,382 2022-2023 234,755 2022-2030 2,216 2022-2023 1,512 2022 IPL 495 2022,2024 8,100 2022-2023 132,019 2022-2030 900 2022-2023 — — WPL 323 2022 12,282 2022-2023 102,736 2022-2030 1,316 2022-2023 1,512 2022 Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Current derivative assets $217 $113 $131 $48 $86 $65 Non-current derivative assets 142 63 76 36 66 27 Current derivative liabilities 84 8 58 4 26 4 Non-current derivative liabilities 11 1 9 — 2 1 During the six months ended June 30, 2022, Alliant Energy’s, IPL’s and WPL’s derivative assets increased primarily due to the annual FTR auction operated by MISO and as a result of higher natural gas prices. Alliant Energy’s, IPL’s and WPL’s derivative liabilities increased primarily due to new natural gas contracts entered into in the second quarter of 2022. Based on IPL’s and WPL’s cost recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/liabilities on the balance sheets. Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At June 30, 2022 and December 31, 2021, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered. Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at
IPL [Member]
Derivative Instruments [Line Items]
Derivative Instruments	DERIVATIVE INSTRUMENTS Commodity Derivatives - Notional Amounts - As of June 30, 2022, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 818 2022,2024 20,382 2022-2023 234,755 2022-2030 2,216 2022-2023 1,512 2022 IPL 495 2022,2024 8,100 2022-2023 132,019 2022-2030 900 2022-2023 — — WPL 323 2022 12,282 2022-2023 102,736 2022-2030 1,316 2022-2023 1,512 2022 Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Current derivative assets $217 $113 $131 $48 $86 $65 Non-current derivative assets 142 63 76 36 66 27 Current derivative liabilities 84 8 58 4 26 4 Non-current derivative liabilities 11 1 9 — 2 1 During the six months ended June 30, 2022, Alliant Energy’s, IPL’s and WPL’s derivative assets increased primarily due to the annual FTR auction operated by MISO and as a result of higher natural gas prices. Alliant Energy’s, IPL’s and WPL’s derivative liabilities increased primarily due to new natural gas contracts entered into in the second quarter of 2022. Based on IPL’s and WPL’s cost recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/liabilities on the balance sheets. Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At June 30, 2022 and December 31, 2021, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered. Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at
WPL [Member]
Derivative Instruments [Line Items]
Derivative Instruments	DERIVATIVE INSTRUMENTS Commodity Derivatives - Notional Amounts - As of June 30, 2022, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 818 2022,2024 20,382 2022-2023 234,755 2022-2030 2,216 2022-2023 1,512 2022 IPL 495 2022,2024 8,100 2022-2023 132,019 2022-2030 900 2022-2023 — — WPL 323 2022 12,282 2022-2023 102,736 2022-2030 1,316 2022-2023 1,512 2022 Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Current derivative assets $217 $113 $131 $48 $86 $65 Non-current derivative assets 142 63 76 36 66 27 Current derivative liabilities 84 8 58 4 26 4 Non-current derivative liabilities 11 1 9 — 2 1 During the six months ended June 30, 2022, Alliant Energy’s, IPL’s and WPL’s derivative assets increased primarily due to the annual FTR auction operated by MISO and as a result of higher natural gas prices. Alliant Energy’s, IPL’s and WPL’s derivative liabilities increased primarily due to new natural gas contracts entered into in the second quarter of 2022. Based on IPL’s and WPL’s cost recovery mechanisms, the changes in the fair value of derivative liabilities/assets resulted in comparable changes to regulatory assets/liabilities on the balance sheets. Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At June 30, 2022 and December 31, 2021, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered. Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2022
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 359 — 272 87 359 176 — 146 30 176 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 95 — 80 15 95 9 — 8 1 9 Long-term debt (incl. current maturities) 7,714 — 7,402 1 7,403 7,368 — 8,329 1 8,330 IPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 207 — 138 69 207 84 — 65 19 84 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 67 — 56 11 67 4 — 3 1 4 Long-term debt 3,645 — 3,445 — 3,445 3,643 — 4,124 — 4,124 WPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $152 $— $134 $18 $152 $92 $— $81 $11 $92 Liabilities: Derivatives 28 — 24 4 28 5 — 5 — 5 Long-term debt (incl. current maturities) 2,430 — 2,370 — 2,370 2,429 — 2,862 — 2,862 Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $10 $15 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (10) 8 — — Purchases 79 21 — — Settlements (a) (7) (5) 17 47 Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($10) $8 $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $29 $29 $214 $188 Total net gains (losses) included in changes in net assets (realized/unrealized) (16) 1 — — Purchases 79 21 — — Settlements (a) (20) (12) 30 (34) Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($16) $1 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $7 $14 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (3) 4 — — Purchases 58 16 — — Settlements (a) (4) (4) 17 47 Ending balance, June 30 $58 $30 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($3) $4 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $18 $26 $214 $188 Total net losses included in changes in net assets (realized/unrealized) (7) (2) — — Purchases 58 16 — — Settlements (a) (11) (10) 30 (34) Ending balance, June 30 $58 $30 $244 $154 The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30 ($8) ($2) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended June 30 2022 2021 Beginning balance, April 1 $3 $1 Total net gains (losses) included in changes in net assets (realized/unrealized) (7) 4 Purchases 21 5 Settlements (3) (1) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($7) $4 WPL Commodity Contract Derivative Assets and (Liabilities), net Six Months Ended June 30 2022 2021 Beginning balance, January 1 $11 $3 Total net gains (losses) included in changes in net assets (realized/unrealized) (9) 3 Purchases 21 5 Settlements (9) (2) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($8) $3 (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold. Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs June 30, 2022 ($11) $83 ($8) $66 ($3) $17 December 31, 2021 9 20 8 10 1 10
IPL [Member]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 359 — 272 87 359 176 — 146 30 176 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 95 — 80 15 95 9 — 8 1 9 Long-term debt (incl. current maturities) 7,714 — 7,402 1 7,403 7,368 — 8,329 1 8,330 IPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 207 — 138 69 207 84 — 65 19 84 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 67 — 56 11 67 4 — 3 1 4 Long-term debt 3,645 — 3,445 — 3,445 3,643 — 4,124 — 4,124 WPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $152 $— $134 $18 $152 $92 $— $81 $11 $92 Liabilities: Derivatives 28 — 24 4 28 5 — 5 — 5 Long-term debt (incl. current maturities) 2,430 — 2,370 — 2,370 2,429 — 2,862 — 2,862 Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $10 $15 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (10) 8 — — Purchases 79 21 — — Settlements (a) (7) (5) 17 47 Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($10) $8 $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $29 $29 $214 $188 Total net gains (losses) included in changes in net assets (realized/unrealized) (16) 1 — — Purchases 79 21 — — Settlements (a) (20) (12) 30 (34) Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($16) $1 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $7 $14 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (3) 4 — — Purchases 58 16 — — Settlements (a) (4) (4) 17 47 Ending balance, June 30 $58 $30 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($3) $4 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $18 $26 $214 $188 Total net losses included in changes in net assets (realized/unrealized) (7) (2) — — Purchases 58 16 — — Settlements (a) (11) (10) 30 (34) Ending balance, June 30 $58 $30 $244 $154 The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30 ($8) ($2) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended June 30 2022 2021 Beginning balance, April 1 $3 $1 Total net gains (losses) included in changes in net assets (realized/unrealized) (7) 4 Purchases 21 5 Settlements (3) (1) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($7) $4 WPL Commodity Contract Derivative Assets and (Liabilities), net Six Months Ended June 30 2022 2021 Beginning balance, January 1 $11 $3 Total net gains (losses) included in changes in net assets (realized/unrealized) (9) 3 Purchases 21 5 Settlements (9) (2) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($8) $3 (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold. Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs June 30, 2022 ($11) $83 ($8) $66 ($3) $17 December 31, 2021 9 20 8 10 1 10
WPL [Member]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 359 — 272 87 359 176 — 146 30 176 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 95 — 80 15 95 9 — 8 1 9 Long-term debt (incl. current maturities) 7,714 — 7,402 1 7,403 7,368 — 8,329 1 8,330 IPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 207 — 138 69 207 84 — 65 19 84 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 67 — 56 11 67 4 — 3 1 4 Long-term debt 3,645 — 3,445 — 3,445 3,643 — 4,124 — 4,124 WPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $152 $— $134 $18 $152 $92 $— $81 $11 $92 Liabilities: Derivatives 28 — 24 4 28 5 — 5 — 5 Long-term debt (incl. current maturities) 2,430 — 2,370 — 2,370 2,429 — 2,862 — 2,862 Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $10 $15 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (10) 8 — — Purchases 79 21 — — Settlements (a) (7) (5) 17 47 Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($10) $8 $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $29 $29 $214 $188 Total net gains (losses) included in changes in net assets (realized/unrealized) (16) 1 — — Purchases 79 21 — — Settlements (a) (20) (12) 30 (34) Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($16) $1 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $7 $14 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (3) 4 — — Purchases 58 16 — — Settlements (a) (4) (4) 17 47 Ending balance, June 30 $58 $30 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($3) $4 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $18 $26 $214 $188 Total net losses included in changes in net assets (realized/unrealized) (7) (2) — — Purchases 58 16 — — Settlements (a) (11) (10) 30 (34) Ending balance, June 30 $58 $30 $244 $154 The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30 ($8) ($2) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended June 30 2022 2021 Beginning balance, April 1 $3 $1 Total net gains (losses) included in changes in net assets (realized/unrealized) (7) 4 Purchases 21 5 Settlements (3) (1) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($7) $4 WPL Commodity Contract Derivative Assets and (Liabilities), net Six Months Ended June 30 2022 2021 Beginning balance, January 1 $11 $3 Total net gains (losses) included in changes in net assets (realized/unrealized) (9) 3 Purchases 21 5 Settlements (9) (2) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($8) $3 (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold. Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs June 30, 2022 ($11) $83 ($8) $66 ($3) $17 December 31, 2021 9 20 8 10 1 10

Commitments And Contingencies

Commitments And Contingencies	6 Months Ended
	Jun. 30, 2022
Commitments and Contingencies Disclosure	COMMITMENTS AND CONTINGENCIES NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including WPL’s expansion of solar generation. At June 30, 2022, Alliant Energy’s and WPL’s minimum future commitments for these projects were $332 million and $330 million, respectively. NOTE 13(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At June 30, 2022, related minimum future commitments were as follows (in millions): Alliant Energy IPL WPL Natural gas $1,396 $691 $705 Coal 148 72 76 Other (a) 114 57 28 $1,658 $820 $809 (a) Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2022. NOTE 13(c) Guarantees and Indemnifications - Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. The guarantees do not include a maximum limit. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships, and currently known obligations include costs associated with the future abandonment of certain facilities owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC may need to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations. As of June 30, 2022, the currently known partnership obligations for the abandonment obligations are estimated at $58 million, which represents Alliant Energy’s currently estimated maximum exposure under the guarantees. Alliant Energy estimates its expected loss to be a portion of the $58 million of known partnership abandonment obligations of the Whiting Petroleum affiliate and the other partners. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to pay; however, as of both June 30, 2022 and December 31, 2021, a liability of $5 million is recorded in “Other liabilities” on Alliant Energy’s balance sheets for expected credit losses related to the contingent obligations that are in the scope of these guarantees. Whiting Petroleum completed a business combination with Oasis Petroleum Inc. in July 2022. The combined operations are now known as Chord Energy Corporation. The business combination is not expected to affect the scope of the Whiting Petroleum affiliate’s obligations to Alliant Energy or Alliant Energy’s related guarantees. Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $67 million as of June 30, 2022 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of June 30, 2022 and December 31, 2021. NOTE 13(d) Environmental Matters - Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At June 30, 2022, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At June 30, 2022, such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $9 - $25 $6 - $19 Current and non-current environmental liabilities $12 $8 IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential Clean Air Act issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers. Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however, future capital investments and/or modifications to EGUs and electric and gas distribution systems to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act. NOTE 13(e) Collective Bargaining Agreements - In May 2022, WPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 965 expired and a new agreement was reached, which expires May 31, 2026.
IPL [Member]
Commitments and Contingencies Disclosure	COMMITMENTS AND CONTINGENCIES NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including WPL’s expansion of solar generation. At June 30, 2022, Alliant Energy’s and WPL’s minimum future commitments for these projects were $332 million and $330 million, respectively. NOTE 13(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At June 30, 2022, related minimum future commitments were as follows (in millions): Alliant Energy IPL WPL Natural gas $1,396 $691 $705 Coal 148 72 76 Other (a) 114 57 28 $1,658 $820 $809 (a) Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2022. NOTE 13(c) Guarantees and Indemnifications - Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. The guarantees do not include a maximum limit. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships, and currently known obligations include costs associated with the future abandonment of certain facilities owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC may need to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations. As of June 30, 2022, the currently known partnership obligations for the abandonment obligations are estimated at $58 million, which represents Alliant Energy’s currently estimated maximum exposure under the guarantees. Alliant Energy estimates its expected loss to be a portion of the $58 million of known partnership abandonment obligations of the Whiting Petroleum affiliate and the other partners. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to pay; however, as of both June 30, 2022 and December 31, 2021, a liability of $5 million is recorded in “Other liabilities” on Alliant Energy’s balance sheets for expected credit losses related to the contingent obligations that are in the scope of these guarantees. Whiting Petroleum completed a business combination with Oasis Petroleum Inc. in July 2022. The combined operations are now known as Chord Energy Corporation. The business combination is not expected to affect the scope of the Whiting Petroleum affiliate’s obligations to Alliant Energy or Alliant Energy’s related guarantees. Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $67 million as of June 30, 2022 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of June 30, 2022 and December 31, 2021. NOTE 13(d) Environmental Matters - Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At June 30, 2022, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At June 30, 2022, such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $9 - $25 $6 - $19 Current and non-current environmental liabilities $12 $8 IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential Clean Air Act issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers. Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however, future capital investments and/or modifications to EGUs and electric and gas distribution systems to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act.
WPL [Member]
Commitments and Contingencies Disclosure	COMMITMENTS AND CONTINGENCIES NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including WPL’s expansion of solar generation. At June 30, 2022, Alliant Energy’s and WPL’s minimum future commitments for these projects were $332 million and $330 million, respectively. NOTE 13(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At June 30, 2022, related minimum future commitments were as follows (in millions): Alliant Energy IPL WPL Natural gas $1,396 $691 $705 Coal 148 72 76 Other (a) 114 57 28 $1,658 $820 $809 (a) Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2022. NOTE 13(c) Guarantees and Indemnifications - Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. The guarantees do not include a maximum limit. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships, and currently known obligations include costs associated with the future abandonment of certain facilities owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC may need to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations. As of June 30, 2022, the currently known partnership obligations for the abandonment obligations are estimated at $58 million, which represents Alliant Energy’s currently estimated maximum exposure under the guarantees. Alliant Energy estimates its expected loss to be a portion of the $58 million of known partnership abandonment obligations of the Whiting Petroleum affiliate and the other partners. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to pay; however, as of both June 30, 2022 and December 31, 2021, a liability of $5 million is recorded in “Other liabilities” on Alliant Energy’s balance sheets for expected credit losses related to the contingent obligations that are in the scope of these guarantees. Whiting Petroleum completed a business combination with Oasis Petroleum Inc. in July 2022. The combined operations are now known as Chord Energy Corporation. The business combination is not expected to affect the scope of the Whiting Petroleum affiliate’s obligations to Alliant Energy or Alliant Energy’s related guarantees. Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $67 million as of June 30, 2022 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of June 30, 2022 and December 31, 2021. NOTE 13(d) Environmental Matters - Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At June 30, 2022, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At June 30, 2022, such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $9 - $25 $6 - $19 Current and non-current environmental liabilities $12 $8 IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential Clean Air Act issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers. Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however, future capital investments and/or modifications to EGUs and electric and gas distribution systems to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act. NOTE 13(e) Collective Bargaining Agreements - In May 2022, WPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 965 expired and a new agreement was reached, which expires May 31, 2026.

Segments Of Business

Segments Of Business	6 Months Ended
	Jun. 30, 2022
Segment Reporting Information [Line Items]
Segments Of Business	SEGMENTS OF BUSINESS Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations. Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended June 30, 2022 Revenues $812 $94 $13 $919 $24 $943 Operating income 195 8 1 204 8 212 Net income attributable to Alliant Energy common shareowners 150 9 159 Three Months Ended June 30, 2021 Revenues $717 $69 $10 $796 $21 $817 Operating income (loss) 164 3 (1) 166 10 176 Net income attributable to Alliant Energy common shareowners 124 20 144 Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Six Months Ended June 30, 2022 Revenues $1,586 $356 $23 $1,965 $47 $2,012 Operating income 376 65 4 445 15 460 Net income attributable to Alliant Energy common shareowners 329 22 351 Six Months Ended June 30, 2021 Revenues $1,418 $239 $23 $1,680 $38 $1,718 Operating income 311 47 1 359 15 374 Net income attributable to Alliant Energy common shareowners 287 28 315 IPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $442 $52 $12 $506 Operating income 104 4 1 109 Net income available for common stock 87 Three Months Ended June 30, 2021 Revenues $402 $43 $10 $455 Operating income 107 3 1 111 Net income available for common stock 86 Six Months Ended June 30, 2022 Revenues $843 $191 $22 $1,056 Operating income 179 36 3 218 Net income available for common stock 173 Six Months Ended June 30, 2021 Revenues $788 $134 $22 $944 Operating income 179 33 2 214 Net income available for common stock 165 WPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $370 $42 $1 $413 Operating income 91 4 — 95 Net income 63 Three Months Ended June 30, 2021 Revenues $315 $26 $— $341 Operating income (loss) 57 — (2) 55 Net income 38 Six Months Ended June 30, 2022 Revenues $743 $165 $1 $909 Operating income 197 29 1 227 Net income 156 Six Months Ended June 30, 2021 Revenues $630 $105 $1 $736 Operating income (loss) 132 14 (1) 145 Net income 122
IPL [Member]
Segment Reporting Information [Line Items]
Segments Of Business	SEGMENTS OF BUSINESS Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations. Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended June 30, 2022 Revenues $812 $94 $13 $919 $24 $943 Operating income 195 8 1 204 8 212 Net income attributable to Alliant Energy common shareowners 150 9 159 Three Months Ended June 30, 2021 Revenues $717 $69 $10 $796 $21 $817 Operating income (loss) 164 3 (1) 166 10 176 Net income attributable to Alliant Energy common shareowners 124 20 144 Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Six Months Ended June 30, 2022 Revenues $1,586 $356 $23 $1,965 $47 $2,012 Operating income 376 65 4 445 15 460 Net income attributable to Alliant Energy common shareowners 329 22 351 Six Months Ended June 30, 2021 Revenues $1,418 $239 $23 $1,680 $38 $1,718 Operating income 311 47 1 359 15 374 Net income attributable to Alliant Energy common shareowners 287 28 315 IPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $442 $52 $12 $506 Operating income 104 4 1 109 Net income available for common stock 87 Three Months Ended June 30, 2021 Revenues $402 $43 $10 $455 Operating income 107 3 1 111 Net income available for common stock 86 Six Months Ended June 30, 2022 Revenues $843 $191 $22 $1,056 Operating income 179 36 3 218 Net income available for common stock 173 Six Months Ended June 30, 2021 Revenues $788 $134 $22 $944 Operating income 179 33 2 214 Net income available for common stock 165 WPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $370 $42 $1 $413 Operating income 91 4 — 95 Net income 63 Three Months Ended June 30, 2021 Revenues $315 $26 $— $341 Operating income (loss) 57 — (2) 55 Net income 38 Six Months Ended June 30, 2022 Revenues $743 $165 $1 $909 Operating income 197 29 1 227 Net income 156 Six Months Ended June 30, 2021 Revenues $630 $105 $1 $736 Operating income (loss) 132 14 (1) 145 Net income 122
WPL [Member]
Segment Reporting Information [Line Items]
Segments Of Business	SEGMENTS OF BUSINESS Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations. Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended June 30, 2022 Revenues $812 $94 $13 $919 $24 $943 Operating income 195 8 1 204 8 212 Net income attributable to Alliant Energy common shareowners 150 9 159 Three Months Ended June 30, 2021 Revenues $717 $69 $10 $796 $21 $817 Operating income (loss) 164 3 (1) 166 10 176 Net income attributable to Alliant Energy common shareowners 124 20 144 Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Six Months Ended June 30, 2022 Revenues $1,586 $356 $23 $1,965 $47 $2,012 Operating income 376 65 4 445 15 460 Net income attributable to Alliant Energy common shareowners 329 22 351 Six Months Ended June 30, 2021 Revenues $1,418 $239 $23 $1,680 $38 $1,718 Operating income 311 47 1 359 15 374 Net income attributable to Alliant Energy common shareowners 287 28 315 IPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $442 $52 $12 $506 Operating income 104 4 1 109 Net income available for common stock 87 Three Months Ended June 30, 2021 Revenues $402 $43 $10 $455 Operating income 107 3 1 111 Net income available for common stock 86 Six Months Ended June 30, 2022 Revenues $843 $191 $22 $1,056 Operating income 179 36 3 218 Net income available for common stock 173 Six Months Ended June 30, 2021 Revenues $788 $134 $22 $944 Operating income 179 33 2 214 Net income available for common stock 165 WPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $370 $42 $1 $413 Operating income 91 4 — 95 Net income 63 Three Months Ended June 30, 2021 Revenues $315 $26 $— $341 Operating income (loss) 57 — (2) 55 Net income 38 Six Months Ended June 30, 2022 Revenues $743 $165 $1 $909 Operating income 197 29 1 227 Net income 156 Six Months Ended June 30, 2021 Revenues $630 $105 $1 $736 Operating income (loss) 132 14 (1) 145 Net income 122

Related Parties

Related Parties	6 Months Ended
	Jun. 30, 2022
Related Party Transactions [Line Items]
Related Parties	RELATED PARTIES Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions): IPL WPL Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 Corporate Services billings $51 $48 $91 $88 $42 $41 $78 $76 Sales credited — 4 — 5 13 6 31 7 Purchases billed 129 99 223 242 39 21 61 47 Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL June 30, 2022 December 31, 2021 June 30, 2022 December 31, 2021 Net payables to Corporate Services $112 $110 $63 $83 ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 ATC billings to WPL $35 $30 $69 $62 WPL billings to ATC 5 6 8 9 WPL owed ATC net amounts of $9 million as of June 30, 2022 and $10 million as of December 31, 2021.
IPL [Member]
Related Party Transactions [Line Items]
Related Parties	RELATED PARTIES Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions): IPL WPL Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 Corporate Services billings $51 $48 $91 $88 $42 $41 $78 $76 Sales credited — 4 — 5 13 6 31 7 Purchases billed 129 99 223 242 39 21 61 47 Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL June 30, 2022 December 31, 2021 June 30, 2022 December 31, 2021 Net payables to Corporate Services $112 $110 $63 $83
WPL [Member]
Related Party Transactions [Line Items]
Related Parties	RELATED PARTIES Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions): IPL WPL Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 Corporate Services billings $51 $48 $91 $88 $42 $41 $78 $76 Sales credited — 4 — 5 13 6 31 7 Purchases billed 129 99 223 242 39 21 61 47 Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL June 30, 2022 December 31, 2021 June 30, 2022 December 31, 2021 Net payables to Corporate Services $112 $110 $63 $83 ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 ATC billings to WPL $35 $30 $69 $62 WPL billings to ATC 5 6 8 9 WPL owed ATC net amounts of $9 million as of June 30, 2022 and $10 million as of December 31, 2021.

Summary Of Significant Accoun_2

Summary Of Significant Accounting Policies (Policy)	6 Months Ended
	Jun. 30, 2022
General, Basis of Accounting	The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2021 Form 10-K .
General, Use of Estimates	A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred.
General, Reclassification	Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.
Variable Interest Entities	A portion of WPL’s solar generation projects is financed, and is expected to be financed, with capital from tax equity partners through joint ventures. In 2022, WPL 2022 Solar Holdco, LLC was formed as a joint venture to own and operate project companies responsible for the construction, ownership and operation of various solar generation assets. Members of the joint venture are a WPL subsidiary (the managing member) and a tax equity partner. In June 2022, the WPL subsidiary and the tax equity partner contributed $62 million and $29 million, respectively, to WPL 2022 Solar Holdco, LLC in exchange for membership interests. In June 2022, $88 million of the contributed funds were paid to WPL in exchange for equity interests in the project companies. Once asset construction is complete, the WPL subsidiary and the tax equity partner will make additional cash contributions based on the fair value of the solar generation assets. Earnings, tax attributes, and cash flows from the joint venture will be allocated to both the WPL subsidiary and the tax equity partner in varying percentages over the life of the partnership. Once the tax equity partner has earned its negotiated rate of return and the agreed upon contractual date has been reached, WPL has the option to purchase the remaining interest in the joint venture from the tax equity partner at fair value. Alliant Energy and WPL consolidate this joint venture as it is a VIE in which WPL holds a variable interest, and WPL controls decisions that are significant to the joint venture’s ongoing operations and economic results (i.e., WPL is the primary beneficiary). The joint venture is subject to profit sharing arrangements in which the allocation of the joint venture’s cash distributions and tax benefits to members is based on factors other than members' relative ownership percentages. As a result, WPL utilizes the Hypothetical Liquidation at Book Value (HLBV) method to allocate proceeds to each partner at the balance sheet date based on the liquidation provisions of the related joint venture's operating agreement and to adjust the amount of the VIE's net income attributable to Alliant Energy and WPL, as well as the noncontrolling interest during the period. In each reporting period, the application of HLBV to WPL’s consolidated VIE results in a difference between the amount of profit from the consolidated joint venture and the amount included in WPL’s regulated rates. WPL is subject to GAAP provisions for regulated operations and recognizes a regulatory liability or regulatory asset for amounts representing the timing difference between WPL’s profit earned from the joint venture and the amount included in regulated rates for recovery of its solar generation projects. The amounts recorded in income will ultimately reflect the amount allowed in regulated rates to recover WPL’s investments over the useful life of the solar projects. Refer to Note 6 for discussion of a noncontrolling interest associated with the joint venture.
IPL [Member]
General, Basis of Accounting	The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2021 Form 10-K .
General, Use of Estimates	A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred.
General, Reclassification	Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.
WPL [Member]
General, Basis of Accounting	The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the SEC. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the 2021 Form 10-K .
General, Use of Estimates	A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred.
General, Reclassification	Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.
Variable Interest Entities	A portion of WPL’s solar generation projects is financed, and is expected to be financed, with capital from tax equity partners through joint ventures. In 2022, WPL 2022 Solar Holdco, LLC was formed as a joint venture to own and operate project companies responsible for the construction, ownership and operation of various solar generation assets. Members of the joint venture are a WPL subsidiary (the managing member) and a tax equity partner. In June 2022, the WPL subsidiary and the tax equity partner contributed $62 million and $29 million, respectively, to WPL 2022 Solar Holdco, LLC in exchange for membership interests. In June 2022, $88 million of the contributed funds were paid to WPL in exchange for equity interests in the project companies. Once asset construction is complete, the WPL subsidiary and the tax equity partner will make additional cash contributions based on the fair value of the solar generation assets. Earnings, tax attributes, and cash flows from the joint venture will be allocated to both the WPL subsidiary and the tax equity partner in varying percentages over the life of the partnership. Once the tax equity partner has earned its negotiated rate of return and the agreed upon contractual date has been reached, WPL has the option to purchase the remaining interest in the joint venture from the tax equity partner at fair value. Alliant Energy and WPL consolidate this joint venture as it is a VIE in which WPL holds a variable interest, and WPL controls decisions that are significant to the joint venture’s ongoing operations and economic results (i.e., WPL is the primary beneficiary). The joint venture is subject to profit sharing arrangements in which the allocation of the joint venture’s cash distributions and tax benefits to members is based on factors other than members' relative ownership percentages. As a result, WPL utilizes the Hypothetical Liquidation at Book Value (HLBV) method to allocate proceeds to each partner at the balance sheet date based on the liquidation provisions of the related joint venture's operating agreement and to adjust the amount of the VIE's net income attributable to Alliant Energy and WPL, as well as the noncontrolling interest during the period. In each reporting period, the application of HLBV to WPL’s consolidated VIE results in a difference between the amount of profit from the consolidated joint venture and the amount included in WPL’s regulated rates. WPL is subject to GAAP provisions for regulated operations and recognizes a regulatory liability or regulatory asset for amounts representing the timing difference between WPL’s profit earned from the joint venture and the amount included in regulated rates for recovery of its solar generation projects. The amounts recorded in income will ultimately reflect the amount allowed in regulated rates to recover WPL’s investments over the useful life of the solar projects. Refer to Note 6 for discussion of a noncontrolling interest associated with the joint venture.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	6 Months Ended
	Jun. 30, 2022
Regulatory Assets [Line Items]
Regulatory Assets	Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $954 $934 $903 $884 $51 $50 Pension and OPEB costs 445 462 220 228 225 234 Asset retirement obligations 140 128 99 89 41 39 Derivatives 101 8 69 4 32 4 Commodity cost recovery 88 42 2 2 86 40 Assets retired early 82 92 61 66 21 26 IPL’s DAEC PPA amendment 78 90 78 90 — — WPL’s Western Wisconsin gas distribution expansion investments 50 52 — — 50 52 Other 113 132 58 80 55 52 $2,051 $1,940 $1,490 $1,443 $561 $497
Regulatory Liabilities	Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $573 $585 $308 $312 $265 $273 Cost of removal obligations 396 384 258 252 138 132 Derivatives 288 166 153 77 135 89 WPL’s West Riverside liquidated damages 34 36 — — 34 36 Electric transmission cost recovery 31 51 11 27 20 24 Other 41 49 21 23 20 26 $1,363 $1,271 $751 $691 $612 $580
IPL [Member]
Regulatory Assets [Line Items]
Regulatory Assets	Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $954 $934 $903 $884 $51 $50 Pension and OPEB costs 445 462 220 228 225 234 Asset retirement obligations 140 128 99 89 41 39 Derivatives 101 8 69 4 32 4 Commodity cost recovery 88 42 2 2 86 40 Assets retired early 82 92 61 66 21 26 IPL’s DAEC PPA amendment 78 90 78 90 — — WPL’s Western Wisconsin gas distribution expansion investments 50 52 — — 50 52 Other 113 132 58 80 55 52 $2,051 $1,940 $1,490 $1,443 $561 $497
Regulatory Liabilities	Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $573 $585 $308 $312 $265 $273 Cost of removal obligations 396 384 258 252 138 132 Derivatives 288 166 153 77 135 89 WPL’s West Riverside liquidated damages 34 36 — — 34 36 Electric transmission cost recovery 31 51 11 27 20 24 Other 41 49 21 23 20 26 $1,363 $1,271 $751 $691 $612 $580
WPL [Member]
Regulatory Assets [Line Items]
Regulatory Assets	Regulatory assets were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $954 $934 $903 $884 $51 $50 Pension and OPEB costs 445 462 220 228 225 234 Asset retirement obligations 140 128 99 89 41 39 Derivatives 101 8 69 4 32 4 Commodity cost recovery 88 42 2 2 86 40 Assets retired early 82 92 61 66 21 26 IPL’s DAEC PPA amendment 78 90 78 90 — — WPL’s Western Wisconsin gas distribution expansion investments 50 52 — — 50 52 Other 113 132 58 80 55 52 $2,051 $1,940 $1,490 $1,443 $561 $497
Regulatory Liabilities	Regulatory liabilities were comprised of the following items (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Tax-related $573 $585 $308 $312 $265 $273 Cost of removal obligations 396 384 258 252 138 132 Derivatives 288 166 153 77 135 89 WPL’s West Riverside liquidated damages 34 36 — — 34 36 Electric transmission cost recovery 31 51 11 27 20 24 Other 41 49 21 23 20 26 $1,363 $1,271 $751 $691 $612 $580

Receivables (Tables)

Receivables (Tables)	6 Months Ended
	Jun. 30, 2022
Receivables [Line Items]
Maximum And Average Outstanding Cash Proceeds	IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 Maximum outstanding aggregate cash proceeds $66 $110 $66 $110 Average outstanding aggregate cash proceeds 18 61 11 46
Attributes of Receivables Sold Under the Receivables Agreement	The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions): June 30, 2022 December 31, 2021 Customer accounts receivable $150 $125 Unbilled utility revenues 119 104 Receivables sold to third party 269 229 Less: cash proceeds 15 1 Deferred proceeds 254 228 Less: allowance for expected credit losses 10 14 Fair value of deferred proceeds $244 $214
Additional Attributes Of Receivables Sold Under The Receivables Agreement	Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 Collections $500 $453 $1,061 $982 Write-offs, net of recoveries 1 1 3 3
IPL [Member]
Receivables [Line Items]
Maximum And Average Outstanding Cash Proceeds	IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 Maximum outstanding aggregate cash proceeds $66 $110 $66 $110 Average outstanding aggregate cash proceeds 18 61 11 46
Attributes of Receivables Sold Under the Receivables Agreement	The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions): June 30, 2022 December 31, 2021 Customer accounts receivable $150 $125 Unbilled utility revenues 119 104 Receivables sold to third party 269 229 Less: cash proceeds 15 1 Deferred proceeds 254 228 Less: allowance for expected credit losses 10 14 Fair value of deferred proceeds $244 $214
Additional Attributes Of Receivables Sold Under The Receivables Agreement	Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 Collections $500 $453 $1,061 $982 Write-offs, net of recoveries 1 1 3 3

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2022
Schedule of Equity Method Investments [Line Items]
Unconsolidated Equity Investments	Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three and six months ended June 30 was as follows (in millions): Three Months Six Months 2022 2021 2022 2021 ATC Holdings ($11) ($11) ($23) ($22) Other (5) (8) (9) (12) ($16) ($19) ($32) ($34)

Common Equity (Tables)

Common Equity (Tables)	6 Months Ended
	Jun. 30, 2022
Schedule of Capitalization, Equity [Line Items]
Common Share Activity	A summary of Alliant Energy’s common stock activity was as follows: Shares outstanding, January 1, 2022 250,474,529 Shareowner Direct Plan 228,935 Equity-based compensation plans 222,768 Shares outstanding, June 30, 2022 250,926,232
Changes in Shareowners' Equity	A summary of changes in shareowners’ equity was as follows (in millions): Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $3 $2,750 $3,336 $— ($12) $— $6,077 Net income attributable to Alliant Energy common shareowners 159 159 Common stock dividends ($0.4275 per share) (108) (108) Shareowner Direct Plan issuances 6 6 Equity-based compensation plans and other 3 3 Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $3 $2,712 $3,063 ($1) ($11) $200 $5,966 Net income attributable to Alliant Energy common shareowners 144 144 Common stock dividends ($0.4025 per share) (101) (101) Shareowner Direct Plan issuances 7 7 Equity-based compensation plans and other 3 3 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $3 $2,749 $3,250 $— ($12) $— $5,990 Net income attributable to Alliant Energy common shareowners 351 351 Common stock dividends ($0.855 per share) (215) (215) Shareowner Direct Plan issuances 13 13 Equity-based compensation plans and other (3) 1 (2) Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $2 $2,704 $2,994 ($1) ($11) $200 $5,888 Net income attributable to Alliant Energy common shareowners 315 315 Common stock dividends ($0.805 per share) (203) (203) Shareowner Direct Plan issuances 1 14 15 Equity-based compensation plans and other 4 4 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $33 $2,807 $935 $— $3,775 Net income available for common stock 87 87 Common stock dividends (80) (80) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $33 $2,752 $957 $200 $3,942 Net income available for common stock 86 86 Common stock dividends (99) (99) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $33 $2,807 $929 $— $3,769 Net income available for common stock 173 173 Common stock dividends (160) (160) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $33 $2,752 $979 $200 $3,964 Net income available for common stock 165 165 Common stock dividends (200) (200) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $66 $1,884 $1,101 $— $3,051 Net income 63 63 Common stock dividends (44) (44) Capital contributions from parent 85 85 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $66 $1,584 $995 $— $2,645 Net income 38 38 Common stock dividends (43) (43) Capital contributions from parent 85 85 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $66 $1,704 $1,053 $— $2,823 Net income 156 156 Common stock dividends (89) (89) Capital contributions from parent 265 265 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $66 $1,459 $953 $— $2,478 Net income 122 122 Common stock dividends (85) (85) Capital contributions from parent 210 210 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725
IPL [Member]
Schedule of Capitalization, Equity [Line Items]
Changes in Shareowners' Equity	A summary of changes in shareowners’ equity was as follows (in millions): Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $3 $2,750 $3,336 $— ($12) $— $6,077 Net income attributable to Alliant Energy common shareowners 159 159 Common stock dividends ($0.4275 per share) (108) (108) Shareowner Direct Plan issuances 6 6 Equity-based compensation plans and other 3 3 Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $3 $2,712 $3,063 ($1) ($11) $200 $5,966 Net income attributable to Alliant Energy common shareowners 144 144 Common stock dividends ($0.4025 per share) (101) (101) Shareowner Direct Plan issuances 7 7 Equity-based compensation plans and other 3 3 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $3 $2,749 $3,250 $— ($12) $— $5,990 Net income attributable to Alliant Energy common shareowners 351 351 Common stock dividends ($0.855 per share) (215) (215) Shareowner Direct Plan issuances 13 13 Equity-based compensation plans and other (3) 1 (2) Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $2 $2,704 $2,994 ($1) ($11) $200 $5,888 Net income attributable to Alliant Energy common shareowners 315 315 Common stock dividends ($0.805 per share) (203) (203) Shareowner Direct Plan issuances 1 14 15 Equity-based compensation plans and other 4 4 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $33 $2,807 $935 $— $3,775 Net income available for common stock 87 87 Common stock dividends (80) (80) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $33 $2,752 $957 $200 $3,942 Net income available for common stock 86 86 Common stock dividends (99) (99) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $33 $2,807 $929 $— $3,769 Net income available for common stock 173 173 Common stock dividends (160) (160) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $33 $2,752 $979 $200 $3,964 Net income available for common stock 165 165 Common stock dividends (200) (200) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $66 $1,884 $1,101 $— $3,051 Net income 63 63 Common stock dividends (44) (44) Capital contributions from parent 85 85 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $66 $1,584 $995 $— $2,645 Net income 38 38 Common stock dividends (43) (43) Capital contributions from parent 85 85 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $66 $1,704 $1,053 $— $2,823 Net income 156 156 Common stock dividends (89) (89) Capital contributions from parent 265 265 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $66 $1,459 $953 $— $2,478 Net income 122 122 Common stock dividends (85) (85) Capital contributions from parent 210 210 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725
WPL [Member]
Schedule of Capitalization, Equity [Line Items]
Changes in Shareowners' Equity	A summary of changes in shareowners’ equity was as follows (in millions): Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $3 $2,750 $3,336 $— ($12) $— $6,077 Net income attributable to Alliant Energy common shareowners 159 159 Common stock dividends ($0.4275 per share) (108) (108) Shareowner Direct Plan issuances 6 6 Equity-based compensation plans and other 3 3 Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $3 $2,712 $3,063 ($1) ($11) $200 $5,966 Net income attributable to Alliant Energy common shareowners 144 144 Common stock dividends ($0.4025 per share) (101) (101) Shareowner Direct Plan issuances 7 7 Equity-based compensation plans and other 3 3 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Additional Other Deferred Common Paid-In Retained Comprehensive Compensation Noncontrolling Total Stock Capital Earnings Loss Trust Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $3 $2,749 $3,250 $— ($12) $— $5,990 Net income attributable to Alliant Energy common shareowners 351 351 Common stock dividends ($0.855 per share) (215) (215) Shareowner Direct Plan issuances 13 13 Equity-based compensation plans and other (3) 1 (2) Contributions from noncontrolling interest 29 29 Ending balance, June 30, 2022 $3 $2,759 $3,387 $— ($12) $29 $6,166 Alliant Energy Total Alliant Energy Common Equity Accumulated Shares in Cumulative Additional Other Deferred Preferred Common Paid-In Retained Comprehensive Compensation Stock Total Stock Capital Earnings Loss Trust of IPL Equity Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $2 $2,704 $2,994 ($1) ($11) $200 $5,888 Net income attributable to Alliant Energy common shareowners 315 315 Common stock dividends ($0.805 per share) (203) (203) Shareowner Direct Plan issuances 1 14 15 Equity-based compensation plans and other 4 4 Ending balance, June 30, 2021 $3 $2,722 $3,106 ($1) ($11) $200 $6,019 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $33 $2,807 $935 $— $3,775 Net income available for common stock 87 87 Common stock dividends (80) (80) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $33 $2,752 $957 $200 $3,942 Net income available for common stock 86 86 Common stock dividends (99) (99) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 IPL Total IPL Common Equity Additional Cumulative Common Paid-In Retained Preferred Total Stock Capital Earnings Stock Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $33 $2,807 $929 $— $3,769 Net income available for common stock 173 173 Common stock dividends (160) (160) Ending balance, June 30, 2022 $33 $2,807 $942 $— $3,782 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $33 $2,752 $979 $200 $3,964 Net income available for common stock 165 165 Common stock dividends (200) (200) Capital contributions from parent 50 50 Ending balance, June 30, 2021 $33 $2,802 $944 $200 $3,979 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Three Months Ended June 30, 2022 Beginning balance, March 31, 2022 $66 $1,884 $1,101 $— $3,051 Net income 63 63 Common stock dividends (44) (44) Capital contributions from parent 85 85 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Three Months Ended June 30, 2021 Beginning balance, March 31, 2021 $66 $1,584 $995 $— $2,645 Net income 38 38 Common stock dividends (43) (43) Capital contributions from parent 85 85 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725 WPL Total WPL Common Equity Additional Common Paid-In Retained Noncontrolling Total Stock Capital Earnings Interest Equity Six Months Ended June 30, 2022 Beginning balance, December 31, 2021 $66 $1,704 $1,053 $— $2,823 Net income 156 156 Common stock dividends (89) (89) Capital contributions from parent 265 265 Contributions from noncontrolling interest 29 29 Other (1) (1) Ending balance, June 30, 2022 $66 $1,968 $1,120 $29 $3,183 Six Months Ended June 30, 2021 Beginning balance, December 31, 2020 $66 $1,459 $953 $— $2,478 Net income 122 122 Common stock dividends (85) (85) Capital contributions from parent 210 210 Ending balance, June 30, 2021 $66 $1,669 $990 $— $2,725

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2022
Short-term Debt [Line Items]
Other Short-Term Borrowings	Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions): June 30, 2022 Alliant Energy IPL WPL Amount outstanding $399 $— $222 Weighted average interest rates 1.8% N/A 1.7% Available credit facility capacity $601 $250 $78 Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Maximum amount outstanding (based on daily outstanding balances) $441 $571 $— $19 $222 $232 Average amount outstanding (based on daily outstanding balances) $337 $452 $— $1 $166 $177 Weighted average interest rates 1.0% 0.2% —% 0.2% 0.9% 0.1% Six Months Ended June 30 Maximum amount outstanding (based on daily outstanding balances) $577 $578 $— $19 $252 $275 Average amount outstanding (based on daily outstanding balances) $390 $438 $— $— $185 $183 Weighted average interest rates 0.6% 0.2% —% 0.2% 0.5% 0.1%
IPL [Member]
Short-term Debt [Line Items]
Other Short-Term Borrowings	Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions): June 30, 2022 Alliant Energy IPL WPL Amount outstanding $399 $— $222 Weighted average interest rates 1.8% N/A 1.7% Available credit facility capacity $601 $250 $78 Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Maximum amount outstanding (based on daily outstanding balances) $441 $571 $— $19 $222 $232 Average amount outstanding (based on daily outstanding balances) $337 $452 $— $1 $166 $177 Weighted average interest rates 1.0% 0.2% —% 0.2% 0.9% 0.1% Six Months Ended June 30 Maximum amount outstanding (based on daily outstanding balances) $577 $578 $— $19 $252 $275 Average amount outstanding (based on daily outstanding balances) $390 $438 $— $— $185 $183 Weighted average interest rates 0.6% 0.2% —% 0.2% 0.5% 0.1%
WPL [Member]
Short-term Debt [Line Items]
Other Short-Term Borrowings	Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper classified as short-term debt was as follows (dollars in millions): June 30, 2022 Alliant Energy IPL WPL Amount outstanding $399 $— $222 Weighted average interest rates 1.8% N/A 1.7% Available credit facility capacity $601 $250 $78 Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Maximum amount outstanding (based on daily outstanding balances) $441 $571 $— $19 $222 $232 Average amount outstanding (based on daily outstanding balances) $337 $452 $— $1 $166 $177 Weighted average interest rates 1.0% 0.2% —% 0.2% 0.9% 0.1% Six Months Ended June 30 Maximum amount outstanding (based on daily outstanding balances) $577 $578 $— $19 $252 $275 Average amount outstanding (based on daily outstanding balances) $390 $438 $— $— $185 $183 Weighted average interest rates 0.6% 0.2% —% 0.2% 0.5% 0.1%

Revenues (Tables)

Revenues (Tables)	6 Months Ended
	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $289 $258 $158 $142 $131 $116 Retail - commercial 196 175 127 115 69 60 Retail - industrial 244 210 136 116 108 94 Wholesale 54 47 16 15 38 32 Bulk power and other 29 27 5 14 24 13 Total Electric Utility 812 717 442 402 370 315 Gas Utility: Retail - residential 51 39 28 24 23 15 Retail - commercial 27 19 14 12 13 7 Retail - industrial 3 3 2 2 1 1 Transportation/other 13 8 8 5 5 3 Total Gas Utility 94 69 52 43 42 26 Other Utility: Steam 11 9 11 9 — — Other utility 2 1 1 1 1 — Total Other Utility 13 10 12 10 1 — Non-Utility and Other: Travero and other 24 21 — — — — Total Non-Utility and Other 24 21 — — — — Total revenues $943 $817 $506 $455 $413 $341 Alliant Energy IPL WPL Six Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $581 $520 $308 $281 $273 $239 Retail - commercial 386 347 246 225 140 122 Retail - industrial 453 412 246 228 207 184 Wholesale 101 87 31 26 70 61 Bulk power and other 65 52 12 28 53 24 Total Electric Utility 1,586 1,418 843 788 743 630 Gas Utility: Retail - residential 210 138 113 76 97 62 Retail - commercial 109 72 54 39 55 33 Retail - industrial 11 8 7 5 4 3 Transportation/other 26 21 17 14 9 7 Total Gas Utility 356 239 191 134 165 105 Other Utility: Steam 20 18 20 18 — — Other utility 3 5 2 4 1 1 Total Other Utility 23 23 22 22 1 1 Non-Utility and Other: Travero and other 47 38 — — — — Total Non-Utility and Other 47 38 — — — — Total revenues $2,012 $1,718 $1,056 $944 $909 $736
IPL [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $289 $258 $158 $142 $131 $116 Retail - commercial 196 175 127 115 69 60 Retail - industrial 244 210 136 116 108 94 Wholesale 54 47 16 15 38 32 Bulk power and other 29 27 5 14 24 13 Total Electric Utility 812 717 442 402 370 315 Gas Utility: Retail - residential 51 39 28 24 23 15 Retail - commercial 27 19 14 12 13 7 Retail - industrial 3 3 2 2 1 1 Transportation/other 13 8 8 5 5 3 Total Gas Utility 94 69 52 43 42 26 Other Utility: Steam 11 9 11 9 — — Other utility 2 1 1 1 1 — Total Other Utility 13 10 12 10 1 — Non-Utility and Other: Travero and other 24 21 — — — — Total Non-Utility and Other 24 21 — — — — Total revenues $943 $817 $506 $455 $413 $341 Alliant Energy IPL WPL Six Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $581 $520 $308 $281 $273 $239 Retail - commercial 386 347 246 225 140 122 Retail - industrial 453 412 246 228 207 184 Wholesale 101 87 31 26 70 61 Bulk power and other 65 52 12 28 53 24 Total Electric Utility 1,586 1,418 843 788 743 630 Gas Utility: Retail - residential 210 138 113 76 97 62 Retail - commercial 109 72 54 39 55 33 Retail - industrial 11 8 7 5 4 3 Transportation/other 26 21 17 14 9 7 Total Gas Utility 356 239 191 134 165 105 Other Utility: Steam 20 18 20 18 — — Other utility 3 5 2 4 1 1 Total Other Utility 23 23 22 22 1 1 Non-Utility and Other: Travero and other 47 38 — — — — Total Non-Utility and Other 47 38 — — — — Total revenues $2,012 $1,718 $1,056 $944 $909 $736
WPL [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue	Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions): Alliant Energy IPL WPL Three Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $289 $258 $158 $142 $131 $116 Retail - commercial 196 175 127 115 69 60 Retail - industrial 244 210 136 116 108 94 Wholesale 54 47 16 15 38 32 Bulk power and other 29 27 5 14 24 13 Total Electric Utility 812 717 442 402 370 315 Gas Utility: Retail - residential 51 39 28 24 23 15 Retail - commercial 27 19 14 12 13 7 Retail - industrial 3 3 2 2 1 1 Transportation/other 13 8 8 5 5 3 Total Gas Utility 94 69 52 43 42 26 Other Utility: Steam 11 9 11 9 — — Other utility 2 1 1 1 1 — Total Other Utility 13 10 12 10 1 — Non-Utility and Other: Travero and other 24 21 — — — — Total Non-Utility and Other 24 21 — — — — Total revenues $943 $817 $506 $455 $413 $341 Alliant Energy IPL WPL Six Months Ended June 30 2022 2021 2022 2021 2022 2021 Electric Utility: Retail - residential $581 $520 $308 $281 $273 $239 Retail - commercial 386 347 246 225 140 122 Retail - industrial 453 412 246 228 207 184 Wholesale 101 87 31 26 70 61 Bulk power and other 65 52 12 28 53 24 Total Electric Utility 1,586 1,418 843 788 743 630 Gas Utility: Retail - residential 210 138 113 76 97 62 Retail - commercial 109 72 54 39 55 33 Retail - industrial 11 8 7 5 4 3 Transportation/other 26 21 17 14 9 7 Total Gas Utility 356 239 191 134 165 105 Other Utility: Steam 20 18 20 18 — — Other utility 3 5 2 4 1 1 Total Other Utility 23 23 22 22 1 1 Non-Utility and Other: Travero and other 47 38 — — — — Total Non-Utility and Other 47 38 — — — — Total revenues $2,012 $1,718 $1,056 $944 $909 $736

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2022
Income Taxes [Line Items]
Schedule Of Effective Income Tax Rates	Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. The increases in Alliant Energy’s and WPL’s overall effective income tax rates for the three and six months ended June 30, 2022 compared to the same periods in 2021 were primarily due to decreased amortization of excess deferred taxes primarily at WPL. Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Overall income tax rate 2% (13%) 3% (16%) (16%) (13%) (15%) (15%) 18% (23%) 18% (27%)
Summary Of Tax Credit Carryforwards	At June 30, 2022, carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2037 $41 $38 $— State net operating losses 2022-2042 556 10 2 Federal tax credits 2022-2042 620 396 201
IPL [Member]
Income Taxes [Line Items]
Schedule Of Effective Income Tax Rates	Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. The increases in Alliant Energy’s and WPL’s overall effective income tax rates for the three and six months ended June 30, 2022 compared to the same periods in 2021 were primarily due to decreased amortization of excess deferred taxes primarily at WPL. Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Overall income tax rate 2% (13%) 3% (16%) (16%) (13%) (15%) (15%) 18% (23%) 18% (27%)
Summary Of Tax Credit Carryforwards	At June 30, 2022, carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2037 $41 $38 $— State net operating losses 2022-2042 556 10 2 Federal tax credits 2022-2042 620 396 201
WPL [Member]
Income Taxes [Line Items]
Schedule Of Effective Income Tax Rates	Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. The increases in Alliant Energy’s and WPL’s overall effective income tax rates for the three and six months ended June 30, 2022 compared to the same periods in 2021 were primarily due to decreased amortization of excess deferred taxes primarily at WPL. Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Overall income tax rate 2% (13%) 3% (16%) (16%) (13%) (15%) (15%) 18% (23%) 18% (27%)
Summary Of Tax Credit Carryforwards	At June 30, 2022, carryforwards and expiration dates were estimated as follows (in millions): Range of Expiration Dates Alliant Energy IPL WPL Federal net operating losses 2037 $41 $38 $— State net operating losses 2022-2042 556 10 2 Federal tax credits 2022-2042 620 396 201

Benefit Plans (Tables)

Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Net Periodic Benefit Costs	The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans. Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months Alliant Energy 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $2 $3 $4 $6 $1 $1 $2 $2 Interest cost 9 9 18 17 2 1 3 2 Expected return on plan assets (17) (17) (34) (34) (2) (1) (3) (2) Amortization of actuarial loss 8 9 16 19 — 1 1 2 $2 $4 $4 $8 $1 $2 $3 $4 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months IPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $2 $3 $4 $1 $1 $1 $1 Interest cost 4 4 8 8 — — 1 1 Expected return on plan assets (8) (8) (16) (16) (1) (1) (2) (2) Amortization of actuarial loss 4 4 7 8 — 1 — 1 $1 $2 $2 $4 $— $1 $— $1 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months WPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $1 $2 $2 $— $— $— $— Interest cost 4 4 8 8 — 1 1 1 Expected return on plan assets (8) (7) (16) (15) — — — — Amortization of actuarial loss 4 4 8 9 1 — 1 1 $1 $2 $2 $4 $1 $1 $2 $2
Recognized Compensation Expense And Income Tax Benefits	A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Compensation expense $3 $2 $7 $5 $1 $2 $4 $3 $1 $1 $3 $2 Income tax benefits 1 1 2 2 — 1 1 1 — 1 1 1
Schedule Of Equity-based Compensation Plans Activity	For the six months ended June 30, 2022, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. Weighted Average Grants Grant Date Fair Value Performance shares 73,762 $54.45 Performance restricted stock units 84,277 56.97 Restricted stock units 76,876 56.86
IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Net Periodic Benefit Costs	The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans. Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months Alliant Energy 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $2 $3 $4 $6 $1 $1 $2 $2 Interest cost 9 9 18 17 2 1 3 2 Expected return on plan assets (17) (17) (34) (34) (2) (1) (3) (2) Amortization of actuarial loss 8 9 16 19 — 1 1 2 $2 $4 $4 $8 $1 $2 $3 $4 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months IPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $2 $3 $4 $1 $1 $1 $1 Interest cost 4 4 8 8 — — 1 1 Expected return on plan assets (8) (8) (16) (16) (1) (1) (2) (2) Amortization of actuarial loss 4 4 7 8 — 1 — 1 $1 $2 $2 $4 $— $1 $— $1 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months WPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $1 $2 $2 $— $— $— $— Interest cost 4 4 8 8 — 1 1 1 Expected return on plan assets (8) (7) (16) (15) — — — — Amortization of actuarial loss 4 4 8 9 1 — 1 1 $1 $2 $2 $4 $1 $1 $2 $2
Recognized Compensation Expense And Income Tax Benefits	A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Compensation expense $3 $2 $7 $5 $1 $2 $4 $3 $1 $1 $3 $2 Income tax benefits 1 1 2 2 — 1 1 1 — 1 1 1
Schedule Of Equity-based Compensation Plans Activity	For the six months ended June 30, 2022, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. Weighted Average Grants Grant Date Fair Value Performance shares 73,762 $54.45 Performance restricted stock units 84,277 56.97 Restricted stock units 76,876 56.86
WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Net Periodic Benefit Costs	The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and six months ended June 30 are included below (in millions). For IPL and WPL, amounts are for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans. Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months Alliant Energy 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $2 $3 $4 $6 $1 $1 $2 $2 Interest cost 9 9 18 17 2 1 3 2 Expected return on plan assets (17) (17) (34) (34) (2) (1) (3) (2) Amortization of actuarial loss 8 9 16 19 — 1 1 2 $2 $4 $4 $8 $1 $2 $3 $4 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months IPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $2 $3 $4 $1 $1 $1 $1 Interest cost 4 4 8 8 — — 1 1 Expected return on plan assets (8) (8) (16) (16) (1) (1) (2) (2) Amortization of actuarial loss 4 4 7 8 — 1 — 1 $1 $2 $2 $4 $— $1 $— $1 Defined Benefit Pension Plans OPEB Plans Three Months Six Months Three Months Six Months WPL 2022 2021 2022 2021 2022 2021 2022 2021 Service cost $1 $1 $2 $2 $— $— $— $— Interest cost 4 4 8 8 — 1 1 1 Expected return on plan assets (8) (7) (16) (15) — — — — Amortization of actuarial loss 4 4 8 9 1 — 1 1 $1 $2 $2 $4 $1 $1 $2 $2
Recognized Compensation Expense And Income Tax Benefits	A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and six months ended June 30 was as follows (in millions): Alliant Energy IPL WPL Three Months Six Months Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 2022 2021 Compensation expense $3 $2 $7 $5 $1 $2 $4 $3 $1 $1 $3 $2 Income tax benefits 1 1 2 2 — 1 1 1 — 1 1 1
Schedule Of Equity-based Compensation Plans Activity	For the six months ended June 30, 2022, performance shares, performance restricted stock units and restricted stock units were granted to key employees under existing plans as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. Weighted Average Grants Grant Date Fair Value Performance shares 73,762 $54.45 Performance restricted stock units 84,277 56.97 Restricted stock units 76,876 56.86

Derivative Instruments (Tables)

Derivative Instruments (Tables)	6 Months Ended
	Jun. 30, 2022
Derivative Instruments [Line Items]
Notional Amounts Of Derivative Instruments	As of June 30, 2022, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 818 2022,2024 20,382 2022-2023 234,755 2022-2030 2,216 2022-2023 1,512 2022 IPL 495 2022,2024 8,100 2022-2023 132,019 2022-2030 900 2022-2023 — — WPL 323 2022 12,282 2022-2023 102,736 2022-2030 1,316 2022-2023 1,512 2022
Fair Value Of Financial Instruments	Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Current derivative assets $217 $113 $131 $48 $86 $65 Non-current derivative assets 142 63 76 36 66 27 Current derivative liabilities 84 8 58 4 26 4 Non-current derivative liabilities 11 1 9 — 2 1
IPL [Member]
Derivative Instruments [Line Items]
Notional Amounts Of Derivative Instruments	As of June 30, 2022, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 818 2022,2024 20,382 2022-2023 234,755 2022-2030 2,216 2022-2023 1,512 2022 IPL 495 2022,2024 8,100 2022-2023 132,019 2022-2030 900 2022-2023 — — WPL 323 2022 12,282 2022-2023 102,736 2022-2030 1,316 2022-2023 1,512 2022
Fair Value Of Financial Instruments	Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Current derivative assets $217 $113 $131 $48 $86 $65 Non-current derivative assets 142 63 76 36 66 27 Current derivative liabilities 84 8 58 4 26 4 Non-current derivative liabilities 11 1 9 — 2 1
WPL [Member]
Derivative Instruments [Line Items]
Notional Amounts Of Derivative Instruments	As of June 30, 2022, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands): Electricity FTRs Natural Gas Coal Diesel Fuel MWhs Years MWhs Years Dths Years Tons Years Gallons Years Alliant Energy 818 2022,2024 20,382 2022-2023 234,755 2022-2030 2,216 2022-2023 1,512 2022 IPL 495 2022,2024 8,100 2022-2023 132,019 2022-2030 900 2022-2023 — — WPL 323 2022 12,282 2022-2023 102,736 2022-2030 1,316 2022-2023 1,512 2022
Fair Value Of Financial Instruments	Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions): Alliant Energy IPL WPL June 30, December 31, June 30, December 31, June 30, December 31, Current derivative assets $217 $113 $131 $48 $86 $65 Non-current derivative assets 142 63 76 36 66 27 Current derivative liabilities 84 8 58 4 26 4 Non-current derivative liabilities 11 1 9 — 2 1

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2022
Statement [Line Items]
Fair Value Measurements	Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 359 — 272 87 359 176 — 146 30 176 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 95 — 80 15 95 9 — 8 1 9 Long-term debt (incl. current maturities) 7,714 — 7,402 1 7,403 7,368 — 8,329 1 8,330 IPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 207 — 138 69 207 84 — 65 19 84 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 67 — 56 11 67 4 — 3 1 4 Long-term debt 3,645 — 3,445 — 3,445 3,643 — 4,124 — 4,124 WPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $152 $— $134 $18 $152 $92 $— $81 $11 $92 Liabilities: Derivatives 28 — 24 4 28 5 — 5 — 5 Long-term debt (incl. current maturities) 2,430 — 2,370 — 2,370 2,429 — 2,862 — 2,862
Fair Value Measurements Using Significant Unobservable Inputs	Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $10 $15 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (10) 8 — — Purchases 79 21 — — Settlements (a) (7) (5) 17 47 Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($10) $8 $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $29 $29 $214 $188 Total net gains (losses) included in changes in net assets (realized/unrealized) (16) 1 — — Purchases 79 21 — — Settlements (a) (20) (12) 30 (34) Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($16) $1 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $7 $14 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (3) 4 — — Purchases 58 16 — — Settlements (a) (4) (4) 17 47 Ending balance, June 30 $58 $30 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($3) $4 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $18 $26 $214 $188 Total net losses included in changes in net assets (realized/unrealized) (7) (2) — — Purchases 58 16 — — Settlements (a) (11) (10) 30 (34) Ending balance, June 30 $58 $30 $244 $154 The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30 ($8) ($2) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended June 30 2022 2021 Beginning balance, April 1 $3 $1 Total net gains (losses) included in changes in net assets (realized/unrealized) (7) 4 Purchases 21 5 Settlements (3) (1) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($7) $4 WPL Commodity Contract Derivative Assets and (Liabilities), net Six Months Ended June 30 2022 2021 Beginning balance, January 1 $11 $3 Total net gains (losses) included in changes in net assets (realized/unrealized) (9) 3 Purchases 21 5 Settlements (9) (2) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($8) $3 (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.
Fair Value Of Net Derivative Assets (Liabilities)	The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs June 30, 2022 ($11) $83 ($8) $66 ($3) $17 December 31, 2021 9 20 8 10 1 10
IPL [Member]
Statement [Line Items]
Fair Value Measurements	Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 359 — 272 87 359 176 — 146 30 176 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 95 — 80 15 95 9 — 8 1 9 Long-term debt (incl. current maturities) 7,714 — 7,402 1 7,403 7,368 — 8,329 1 8,330 IPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 207 — 138 69 207 84 — 65 19 84 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 67 — 56 11 67 4 — 3 1 4 Long-term debt 3,645 — 3,445 — 3,445 3,643 — 4,124 — 4,124 WPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $152 $— $134 $18 $152 $92 $— $81 $11 $92 Liabilities: Derivatives 28 — 24 4 28 5 — 5 — 5 Long-term debt (incl. current maturities) 2,430 — 2,370 — 2,370 2,429 — 2,862 — 2,862
Fair Value Measurements Using Significant Unobservable Inputs	Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $10 $15 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (10) 8 — — Purchases 79 21 — — Settlements (a) (7) (5) 17 47 Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($10) $8 $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $29 $29 $214 $188 Total net gains (losses) included in changes in net assets (realized/unrealized) (16) 1 — — Purchases 79 21 — — Settlements (a) (20) (12) 30 (34) Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($16) $1 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $7 $14 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (3) 4 — — Purchases 58 16 — — Settlements (a) (4) (4) 17 47 Ending balance, June 30 $58 $30 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($3) $4 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $18 $26 $214 $188 Total net losses included in changes in net assets (realized/unrealized) (7) (2) — — Purchases 58 16 — — Settlements (a) (11) (10) 30 (34) Ending balance, June 30 $58 $30 $244 $154 The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30 ($8) ($2) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended June 30 2022 2021 Beginning balance, April 1 $3 $1 Total net gains (losses) included in changes in net assets (realized/unrealized) (7) 4 Purchases 21 5 Settlements (3) (1) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($7) $4 WPL Commodity Contract Derivative Assets and (Liabilities), net Six Months Ended June 30 2022 2021 Beginning balance, January 1 $11 $3 Total net gains (losses) included in changes in net assets (realized/unrealized) (9) 3 Purchases 21 5 Settlements (9) (2) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($8) $3 (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.
Fair Value Of Net Derivative Assets (Liabilities)	The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs June 30, 2022 ($11) $83 ($8) $66 ($3) $17 December 31, 2021 9 20 8 10 1 10
WPL [Member]
Statement [Line Items]
Fair Value Measurements	Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions): Alliant Energy June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 359 — 272 87 359 176 — 146 30 176 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 95 — 80 15 95 9 — 8 1 9 Long-term debt (incl. current maturities) 7,714 — 7,402 1 7,403 7,368 — 8,329 1 8,330 IPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Money market fund investments $9 $9 $— $— $9 $32 $32 $— $— $32 Derivatives 207 — 138 69 207 84 — 65 19 84 Deferred proceeds 244 — — 244 244 214 — — 214 214 Liabilities: Derivatives 67 — 56 11 67 4 — 3 1 4 Long-term debt 3,645 — 3,445 — 3,445 3,643 — 4,124 — 4,124 WPL June 30, 2022 December 31, 2021 Fair Value Fair Value Carrying Level Level Level Carrying Level Level Level Amount 1 2 3 Total Amount 1 2 3 Total Assets: Derivatives $152 $— $134 $18 $152 $92 $— $81 $11 $92 Liabilities: Derivatives 28 — 24 4 28 5 — 5 — 5 Long-term debt (incl. current maturities) 2,430 — 2,370 — 2,370 2,429 — 2,862 — 2,862
Fair Value Measurements Using Significant Unobservable Inputs	Information for fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions): Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $10 $15 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (10) 8 — — Purchases 79 21 — — Settlements (a) (7) (5) 17 47 Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($10) $8 $— $— Alliant Energy Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $29 $29 $214 $188 Total net gains (losses) included in changes in net assets (realized/unrealized) (16) 1 — — Purchases 79 21 — — Settlements (a) (20) (12) 30 (34) Ending balance, June 30 $72 $39 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($16) $1 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Three Months Ended June 30 2022 2021 2022 2021 Beginning balance, April 1 $7 $14 $227 $107 Total net gains (losses) included in changes in net assets (realized/unrealized) (3) 4 — — Purchases 58 16 — — Settlements (a) (4) (4) 17 47 Ending balance, June 30 $58 $30 $244 $154 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($3) $4 $— $— IPL Commodity Contract Derivative Assets and (Liabilities), net Deferred Proceeds Six Months Ended June 30 2022 2021 2022 2021 Beginning balance, January 1 $18 $26 $214 $188 Total net losses included in changes in net assets (realized/unrealized) (7) (2) — — Purchases 58 16 — — Settlements (a) (11) (10) 30 (34) Ending balance, June 30 $58 $30 $244 $154 The amount of total net losses for the period included in changes in net assets attributable to the change in unrealized losses relating to assets and liabilities held at June 30 ($8) ($2) $— $— WPL Commodity Contract Derivative Assets and (Liabilities), net Three Months Ended June 30 2022 2021 Beginning balance, April 1 $3 $1 Total net gains (losses) included in changes in net assets (realized/unrealized) (7) 4 Purchases 21 5 Settlements (3) (1) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($7) $4 WPL Commodity Contract Derivative Assets and (Liabilities), net Six Months Ended June 30 2022 2021 Beginning balance, January 1 $11 $3 Total net gains (losses) included in changes in net assets (realized/unrealized) (9) 3 Purchases 21 5 Settlements (9) (2) Ending balance, June 30 $14 $9 The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30 ($8) $3 (a) Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for expected credit losses associated with the receivables sold and cash amounts received from the receivables sold.
Fair Value Of Net Derivative Assets (Liabilities)	The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets (liabilities) as follows (in millions): Alliant Energy IPL WPL Excluding FTRs FTRs Excluding FTRs FTRs Excluding FTRs FTRs June 30, 2022 ($11) $83 ($8) $66 ($3) $17 December 31, 2021 9 20 8 10 1 10

Commitments And Contingencies (

Commitments And Contingencies (Tables)	6 Months Ended
	Jun. 30, 2022
Commitments and Contingencies [Line Items]
Other Purchase Commitments	At June 30, 2022, related minimum future commitments were as follows (in millions): Alliant Energy IPL WPL Natural gas $1,396 $691 $705 Coal 148 72 76 Other (a) 114 57 28 $1,658 $820 $809 (a) Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2022.
MGP Site Estimated Future Costs And Recorded Liabilities	At June 30, 2022, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At June 30, 2022, such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $9 - $25 $6 - $19 Current and non-current environmental liabilities $12 $8
IPL [Member]
Commitments and Contingencies [Line Items]
Other Purchase Commitments	At June 30, 2022, related minimum future commitments were as follows (in millions): Alliant Energy IPL WPL Natural gas $1,396 $691 $705 Coal 148 72 76 Other (a) 114 57 28 $1,658 $820 $809 (a) Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2022.
MGP Site Estimated Future Costs And Recorded Liabilities	At June 30, 2022, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At June 30, 2022, such amounts for WPL were not material. Alliant Energy IPL Range of estimated future costs $9 - $25 $6 - $19 Current and non-current environmental liabilities $12 $8
WPL [Member]
Commitments and Contingencies [Line Items]
Other Purchase Commitments	At June 30, 2022, related minimum future commitments were as follows (in millions): Alliant Energy IPL WPL Natural gas $1,396 $691 $705 Coal 148 72 76 Other (a) 114 57 28 $1,658 $820 $809 (a) Includes individual commitments incurred during the normal course of business that exceeded $1 million at June 30, 2022.

Segments Of Business (Tables)

Segments Of Business (Tables)	6 Months Ended
	Jun. 30, 2022
Segment Reporting Information [Line Items]
Schedule Of Segments Of Business	Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations. Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended June 30, 2022 Revenues $812 $94 $13 $919 $24 $943 Operating income 195 8 1 204 8 212 Net income attributable to Alliant Energy common shareowners 150 9 159 Three Months Ended June 30, 2021 Revenues $717 $69 $10 $796 $21 $817 Operating income (loss) 164 3 (1) 166 10 176 Net income attributable to Alliant Energy common shareowners 124 20 144 Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Six Months Ended June 30, 2022 Revenues $1,586 $356 $23 $1,965 $47 $2,012 Operating income 376 65 4 445 15 460 Net income attributable to Alliant Energy common shareowners 329 22 351 Six Months Ended June 30, 2021 Revenues $1,418 $239 $23 $1,680 $38 $1,718 Operating income 311 47 1 359 15 374 Net income attributable to Alliant Energy common shareowners 287 28 315 IPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $442 $52 $12 $506 Operating income 104 4 1 109 Net income available for common stock 87 Three Months Ended June 30, 2021 Revenues $402 $43 $10 $455 Operating income 107 3 1 111 Net income available for common stock 86 Six Months Ended June 30, 2022 Revenues $843 $191 $22 $1,056 Operating income 179 36 3 218 Net income available for common stock 173 Six Months Ended June 30, 2021 Revenues $788 $134 $22 $944 Operating income 179 33 2 214 Net income available for common stock 165 WPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $370 $42 $1 $413 Operating income 91 4 — 95 Net income 63 Three Months Ended June 30, 2021 Revenues $315 $26 $— $341 Operating income (loss) 57 — (2) 55 Net income 38 Six Months Ended June 30, 2022 Revenues $743 $165 $1 $909 Operating income 197 29 1 227 Net income 156 Six Months Ended June 30, 2021 Revenues $630 $105 $1 $736 Operating income (loss) 132 14 (1) 145 Net income 122
IPL [Member]
Segment Reporting Information [Line Items]
Schedule Of Segments Of Business	Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations. Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended June 30, 2022 Revenues $812 $94 $13 $919 $24 $943 Operating income 195 8 1 204 8 212 Net income attributable to Alliant Energy common shareowners 150 9 159 Three Months Ended June 30, 2021 Revenues $717 $69 $10 $796 $21 $817 Operating income (loss) 164 3 (1) 166 10 176 Net income attributable to Alliant Energy common shareowners 124 20 144 Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Six Months Ended June 30, 2022 Revenues $1,586 $356 $23 $1,965 $47 $2,012 Operating income 376 65 4 445 15 460 Net income attributable to Alliant Energy common shareowners 329 22 351 Six Months Ended June 30, 2021 Revenues $1,418 $239 $23 $1,680 $38 $1,718 Operating income 311 47 1 359 15 374 Net income attributable to Alliant Energy common shareowners 287 28 315 IPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $442 $52 $12 $506 Operating income 104 4 1 109 Net income available for common stock 87 Three Months Ended June 30, 2021 Revenues $402 $43 $10 $455 Operating income 107 3 1 111 Net income available for common stock 86 Six Months Ended June 30, 2022 Revenues $843 $191 $22 $1,056 Operating income 179 36 3 218 Net income available for common stock 173 Six Months Ended June 30, 2021 Revenues $788 $134 $22 $944 Operating income 179 33 2 214 Net income available for common stock 165 WPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $370 $42 $1 $413 Operating income 91 4 — 95 Net income 63 Three Months Ended June 30, 2021 Revenues $315 $26 $— $341 Operating income (loss) 57 — (2) 55 Net income 38 Six Months Ended June 30, 2022 Revenues $743 $165 $1 $909 Operating income 197 29 1 227 Net income 156 Six Months Ended June 30, 2021 Revenues $630 $105 $1 $736 Operating income (loss) 132 14 (1) 145 Net income 122
WPL [Member]
Segment Reporting Information [Line Items]
Schedule Of Segments Of Business	Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations. Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Three Months Ended June 30, 2022 Revenues $812 $94 $13 $919 $24 $943 Operating income 195 8 1 204 8 212 Net income attributable to Alliant Energy common shareowners 150 9 159 Three Months Ended June 30, 2021 Revenues $717 $69 $10 $796 $21 $817 Operating income (loss) 164 3 (1) 166 10 176 Net income attributable to Alliant Energy common shareowners 124 20 144 Alliant Energy ATC Holdings, Alliant Utility Non-Utility, Energy Electric Gas Other Total Parent and Other Consolidated (in millions) Six Months Ended June 30, 2022 Revenues $1,586 $356 $23 $1,965 $47 $2,012 Operating income 376 65 4 445 15 460 Net income attributable to Alliant Energy common shareowners 329 22 351 Six Months Ended June 30, 2021 Revenues $1,418 $239 $23 $1,680 $38 $1,718 Operating income 311 47 1 359 15 374 Net income attributable to Alliant Energy common shareowners 287 28 315 IPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $442 $52 $12 $506 Operating income 104 4 1 109 Net income available for common stock 87 Three Months Ended June 30, 2021 Revenues $402 $43 $10 $455 Operating income 107 3 1 111 Net income available for common stock 86 Six Months Ended June 30, 2022 Revenues $843 $191 $22 $1,056 Operating income 179 36 3 218 Net income available for common stock 173 Six Months Ended June 30, 2021 Revenues $788 $134 $22 $944 Operating income 179 33 2 214 Net income available for common stock 165 WPL Electric Gas Other Total (in millions) Three Months Ended June 30, 2022 Revenues $370 $42 $1 $413 Operating income 91 4 — 95 Net income 63 Three Months Ended June 30, 2021 Revenues $315 $26 $— $341 Operating income (loss) 57 — (2) 55 Net income 38 Six Months Ended June 30, 2022 Revenues $743 $165 $1 $909 Operating income 197 29 1 227 Net income 156 Six Months Ended June 30, 2021 Revenues $630 $105 $1 $736 Operating income (loss) 132 14 (1) 145 Net income 122

Related Parties (Tables)

Related Parties (Tables)	6 Months Ended
	Jun. 30, 2022
Related Party Transactions [Line Items]
Services Provided, Sales Credited And Purchases	The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions): IPL WPL Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 Corporate Services billings $51 $48 $91 $88 $42 $41 $78 $76 Sales credited — 4 — 5 13 6 31 7 Purchases billed 129 99 223 242 39 21 61 47
Net Intercompany Payables	Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL June 30, 2022 December 31, 2021 June 30, 2022 December 31, 2021 Net payables to Corporate Services $112 $110 $63 $83
Related Amounts Billed Between Parties	The related amounts billed between the parties for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 ATC billings to WPL $35 $30 $69 $62 WPL billings to ATC 5 6 8 9
IPL [Member]
Related Party Transactions [Line Items]
Services Provided, Sales Credited And Purchases	The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions): IPL WPL Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 Corporate Services billings $51 $48 $91 $88 $42 $41 $78 $76 Sales credited — 4 — 5 13 6 31 7 Purchases billed 129 99 223 242 39 21 61 47
Net Intercompany Payables	Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL June 30, 2022 December 31, 2021 June 30, 2022 December 31, 2021 Net payables to Corporate Services $112 $110 $63 $83
WPL [Member]
Related Party Transactions [Line Items]
Services Provided, Sales Credited And Purchases	The amounts billed for services provided, sales credited and purchases for the three and six months ended June 30 were as follows (in millions): IPL WPL Three Months Six Months Three Months Six Months 2022 2021 2022 2021 2022 2021 2022 2021 Corporate Services billings $51 $48 $91 $88 $42 $41 $78 $76 Sales credited — 4 — 5 13 6 31 7 Purchases billed 129 99 223 242 39 21 61 47
Net Intercompany Payables	Net intercompany payables to Corporate Services were as follows (in millions): IPL WPL June 30, 2022 December 31, 2021 June 30, 2022 December 31, 2021 Net payables to Corporate Services $112 $110 $63 $83
Related Amounts Billed Between Parties	The related amounts billed between the parties for the three and six months ended June 30 were as follows (in millions): Three Months Six Months 2022 2021 2022 2021 ATC billings to WPL $35 $30 $69 $62 WPL billings to ATC 5 6 8 9

Summary Of Significant Accoun_3

Summary Of Significant Accounting Policies (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
WPL's cash contribution	$ 62
Tax equity partner's cash contribution	29
Contributed funds paid to WPL for equity interests	$ 88

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Regulatory Matters [Line Items]
Regulatory assets	$ 2,051	$ 1,940
IPL [Member]
Regulatory Matters [Line Items]
Regulatory assets	1,490	1,443
WPL [Member]
Regulatory Matters [Line Items]
Regulatory assets	561	$ 497
Deferred Fuel Costs | WPL [Member]
Regulatory Matters [Line Items]
Regulatory assets	$ 40

Regulatory Matters (Regulatory

Regulatory Matters (Regulatory Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Regulatory assets	$ 2,051	$ 1,940
Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	954	934
Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	445	462
Asset retirement obligations [Member]
Regulatory Assets [Line Items]
Regulatory assets	140	128
Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	101	8
Commodity cost recovery [Member]
Regulatory Assets [Line Items]
Regulatory assets	88	42
Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	82	92
IPL's DAEC PPA amendment [Member]
Regulatory Assets [Line Items]
Regulatory assets	78	90
WPL's Western Wisconsin gas distribution expansion investments [Member]
Regulatory Assets [Line Items]
Regulatory assets	50	52
Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	113	132
IPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	1,490	1,443
IPL [Member] | Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	903	884
IPL [Member] | Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	220	228
IPL [Member] | Asset retirement obligations [Member]
Regulatory Assets [Line Items]
Regulatory assets	99	89
IPL [Member] | Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	69	4
IPL [Member] | Commodity cost recovery [Member]
Regulatory Assets [Line Items]
Regulatory assets	2	2
IPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	61	66
IPL [Member] | IPL's DAEC PPA amendment [Member]
Regulatory Assets [Line Items]
Regulatory assets	78	90
IPL [Member] | Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	58	80
WPL [Member]
Regulatory Assets [Line Items]
Regulatory assets	561	497
WPL [Member] | Tax-related [Member]
Regulatory Assets [Line Items]
Regulatory assets	51	50
WPL [Member] | Pension and OPEB costs [Member]
Regulatory Assets [Line Items]
Regulatory assets	225	234
WPL [Member] | Asset retirement obligations [Member]
Regulatory Assets [Line Items]
Regulatory assets	41	39
WPL [Member] | Derivatives [Member]
Regulatory Assets [Line Items]
Regulatory assets	32	4
WPL [Member] | Commodity cost recovery [Member]
Regulatory Assets [Line Items]
Regulatory assets	86	40
WPL [Member] | Assets retired early [Member]
Regulatory Assets [Line Items]
Regulatory assets	21	26
WPL [Member] | WPL's Western Wisconsin gas distribution expansion investments [Member]
Regulatory Assets [Line Items]
Regulatory assets	50	52
WPL [Member] | Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	$ 55	$ 52

Regulatory Matters (Regulator_2

Regulatory Matters (Regulatory Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 1,363	$ 1,271
Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	573	585
Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	396	384
Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	288	166
WPL's West Riverside liquidated damages [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	34	36
Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	31	51
Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	41	49
IPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	751	691
IPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	308	312
IPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	258	252
IPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	153	77
IPL [Member] | Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	11	27
IPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	21	23
WPL [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	612	580
WPL [Member] | Tax-related [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	265	273
WPL [Member] | Cost of removal obligations [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	138	132
WPL [Member] | Derivatives [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	135	89
WPL [Member] | WPL's West Riverside liquidated damages [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	34	36
WPL [Member] | Electric transmission cost recovery [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	20	24
WPL [Member] | Other [Member]
Regulatory Liabilities [Line Items]
Regulatory liabilities	$ 20	$ 26

Property, Plant and Equipment (

Property, Plant and Equipment (Narrative) (Details)	6 Months Ended
	Jun. 30, 2022 MW
Edgewater Generating Station | WPL [Member]
Property, Plant and Equipment [Line Items]
Nameplate Capacity (in MW)	414
Columbia Energy Center | WPL [Member]
Property, Plant and Equipment [Line Items]
Nameplate Capacity (in MW)	595
Lansing Generating Station | IPL [Member]
Property, Plant and Equipment [Line Items]
Nameplate Capacity (in MW)	275

Receivables (Narrative) (Detail

Receivables (Narrative) (Details) - Receivables Sold [Member] - IPL [Member] $ in Millions	Jun. 30, 2022 USD ($)
Receivables [Line Items]
Available capacity	$ 95
Financial Asset, Past Due [Member]
Receivables [Line Items]
Outstanding receivables past due	$ 20

Receivables (Maximum And Averag

Receivables (Maximum And Average Outstanding Cash Proceeds) (Details) - IPL [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Maximum [Member]
Receivables [Line Items]
Maximum outstanding aggregate cash proceeds (based on daily outstanding balances)	$ 66	$ 110	$ 66	$ 110
Average [Member]
Receivables [Line Items]
Average outstanding aggregate cash proceeds (based on daily outstanding balances)	$ 18	$ 61	$ 11	$ 46

Receivables (Receivables Sold U

Receivables (Receivables Sold Under The Agreement) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Receivables [Line Items]
Fair value of deferred proceeds	$ 244	$ 214
IPL [Member]
Receivables [Line Items]
Fair value of deferred proceeds	244	214
Receivables Sold [Member] | IPL [Member]
Receivables [Line Items]
Customer accounts receivable	150	125
Unbilled utility revenues	119	104
Receivables sold to third party	269	229
Less: cash proceeds	15	1
Deferred proceeds	254	228
Less: allowance for expected credit losses	10	14
Fair value of deferred proceeds	$ 244	$ 214

Receivables (Additional Attribu

Receivables (Additional Attributes Of Receivables Sold Under The Agreement) (Details) - IPL [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Receivables [Line Items]
Collections	$ 500	$ 453	$ 1,061	$ 982
Write-offs, net of recoveries	$ 1	$ 1	$ 3	$ 3

Investments (Unconsolidated Equ

Investments (Unconsolidated Equity Investments) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Schedule of Equity Method Investments [Line Items]
Equity income from unconsolidated investments, net	$ (16)	$ (19)	$ (32)	$ (34)
ATC Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Equity income from unconsolidated investments, net	(11)	(11)	(23)	(22)
Other [Member]
Schedule of Equity Method Investments [Line Items]
Equity income from unconsolidated investments, net	(5)	(8)	(9)	(12)
Total [Member]
Schedule of Equity Method Investments [Line Items]
Equity income from unconsolidated investments, net	$ (16)	$ (19)	$ (32)	$ (34)

Common Equity (Common Share Act

Common Equity (Common Share Activity) (Details)	6 Months Ended
	Jun. 30, 2022 shares
Common Stock Oustanding [Roll Forward]
Shares outstanding, January 1, 2022 (in shares)	250,474,529
Shareowner Direct Plan (in shares)	228,935
Equity-based compensation plans (in shares)	222,768
Shares outstanding, June 30, 2022 (in shares)	250,926,232

Common Equity (Changes in Share

Common Equity (Changes in Shareowners' Equity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			$ 5,990
Beginning balance	$ 6,077	$ 5,966	5,990	$ 5,888
Net income attributable to common shareowners	159	144	351	315
Net income	159	146	351	320
Common stock dividends	(108)	(101)	(215)	(203)
Shareowner Direct Plan issuances	6	7	13	15
Equity-based compensation plans and other	3	3	(2)	4
Contributions from noncontrolling interest	29		29
Ending balance	6,137		6,137
Ending balance	$ 6,166	$ 6,019	$ 6,166	$ 6,019
Common stock dividends (in dollars per share)	$ 0.4275	$ 0.4025	$ 0.855	$ 0.805
Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	$ 3	$ 3	$ 3	$ 2
Shareowner Direct Plan issuances				1
Ending balance	3	3	3	3
Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,750	2,712	2,749	2,704
Shareowner Direct Plan issuances	6	7	13	14
Equity-based compensation plans and other	3	3	(3)	4
Ending balance	2,759	2,722	2,759	2,722
Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	3,336	3,063	3,250	2,994
Net income attributable to common shareowners	159	144	351	315
Common stock dividends	(108)	(101)	(215)	(203)
Equity-based compensation plans and other			1
Ending balance	3,387	3,106	3,387	3,106
Accumulated Other Comprehensive Loss [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	0	(1)	0	(1)
Ending balance	0	(1)	0	(1)
Shares in Deferred Compensation Trust [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	(12)	(11)	(12)	(11)
Ending balance	(12)	(11)	(12)	(11)
Noncontrolling Interest [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	0		0
Contributions from noncontrolling interest	29		29
Ending balance	29		29
Cumulative Preferred Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance		200		200
Ending balance		200		200
IPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			3,769
Beginning balance	3,775	3,942	3,769	3,964
Net income attributable to common shareowners	87	86	173	165
Net income	87	88	173	170
Common stock dividends	(80)	(99)	(160)	(200)
Capital contributions from parent		50	0	50
Ending balance	3,782		3,782
Ending balance	3,782	3,979	3,782	3,979
IPL [Member] | Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	33	33	33	33
Ending balance	33	33	33	33
IPL [Member] | Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	2,807	2,752	2,807	2,752
Capital contributions from parent		50		50
Ending balance	2,807	2,802	2,807	2,802
IPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	935	957	929	979
Net income attributable to common shareowners	87	86	173	165
Common stock dividends	(80)	(99)	(160)	(200)
Ending balance	942	944	942	944
IPL [Member] | Cumulative Preferred Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	0	200	0	200
Ending balance	0	200	0	200
WPL [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance			2,823
Beginning balance	3,051	2,645	2,823	2,478
Net income	63	38	156	122
Common stock dividends	(44)	(43)	(89)	(85)
Equity-based compensation plans and other	(1)		(1)
Capital contributions from parent	85	85	265	210
Contributions from noncontrolling interest	29		29
Ending balance	3,154		3,154
Ending balance	3,183	2,725	3,183	2,725
WPL [Member] | Common Stock [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	66	66	66	66
Ending balance	66	66	66	66
WPL [Member] | Additional Paid-in Capital [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	1,884	1,584	1,704	1,459
Equity-based compensation plans and other	(1)		(1)
Capital contributions from parent	85	85	265	210
Ending balance	1,968	1,669	1,968	1,669
WPL [Member] | Retained Earnings [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	1,101	995	1,053	953
Net income	63	38	156	122
Common stock dividends	(44)	(43)	(89)	(85)
Ending balance	1,120	990	1,120	990
WPL [Member] | Noncontrolling Interest [Member]
Changes in Shareowners' Equity Roll Forward [Line Items]
Beginning balance	0	0	0	0
Contributions from noncontrolling interest	29		29
Ending balance	$ 29	$ 0	$ 29	$ 0

Debt (Narrative) (Details)

Debt (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Senior Notes [Member] | 3.6% senior notes, due 2032 [Member]
Debt [Line Items]
Long-term debt	$ 350
Interest rate, percent	3.60%
Term Loan Credit Agreement [Member] | Term loan credit agreement through March 2024
Debt [Line Items]
Long-term debt	$ 300
Interest rate, percent	2%
Term Loan Credit Agreement [Member] | Term loan credit agreement through March 2022
Debt [Line Items]
Long-term debt		$ 300

Debt (Credit Facilities) (Detai

Debt (Credit Facilities) (Details) $ in Millions	Jun. 30, 2022 USD ($)
Debt [Line Items]
Amount outstanding	$ 399
Weighted average interest rates	1.80%
Available credit facility capacity	$ 601
IPL [Member]
Debt [Line Items]
Amount outstanding	0
Available credit facility capacity	250
WPL [Member]
Debt [Line Items]
Amount outstanding	$ 222
Weighted average interest rates	1.70%
Available credit facility capacity	$ 78

Debt (Other Short-Term Borrowin

Debt (Other Short-Term Borrowings) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Debt [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 441	$ 571	$ 577	$ 578
Average amount outstanding (based on daily outstanding balances)	$ 337	$ 452	$ 390	$ 438
Weighted average interest rates	1%	0.20%	0.60%	0.20%
IPL [Member]
Debt [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 0	$ 19	$ 0	$ 19
Average amount outstanding (based on daily outstanding balances)	$ 0	$ 1	$ 0	$ 0
Weighted average interest rates	0%	0.20%	0%	0.20%
WPL [Member]
Debt [Line Items]
Maximum amount outstanding (based on daily outstanding balances)	$ 222	$ 232	$ 252	$ 275
Average amount outstanding (based on daily outstanding balances)	$ 166	$ 177	$ 185	$ 183
Weighted average interest rates	0.90%	0.10%	0.50%	0.10%

Revenue (Disaggregation of Reve

Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 943	$ 817	$ 2,012	$ 1,718
Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	812	717	1,586	1,418
Electric [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	289	258	581	520
Electric [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	196	175	386	347
Electric [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	244	210	453	412
Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	54	47	101	87
Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	29	27	65	52
Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	94	69	356	239
Gas [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	51	39	210	138
Gas [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	27	19	109	72
Gas [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3	3	11	8
Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	13	8	26	21
Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	13	10	23	23
Other Utility [Member] | Steam [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	11	9	20	18
Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2	1	3	5
Non-utility and Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	24	21	47	38
Non-utility and Other [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	24	21	47	38
IPL [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	506	455	1,056	944
IPL [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	442	402	843	788
IPL [Member] | Electric [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	158	142	308	281
IPL [Member] | Electric [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	127	115	246	225
IPL [Member] | Electric [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	136	116	246	228
IPL [Member] | Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16	15	31	26
IPL [Member] | Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5	14	12	28
IPL [Member] | Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	52	43	191	134
IPL [Member] | Gas [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	28	24	113	76
IPL [Member] | Gas [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14	12	54	39
IPL [Member] | Gas [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2	2	7	5
IPL [Member] | Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	8	5	17	14
IPL [Member] | Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12	10	22	22
IPL [Member] | Other Utility [Member] | Steam [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	11	9	20	18
IPL [Member] | Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	1	2	4
WPL [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	413	341	909	736
WPL [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	370	315	743	630
WPL [Member] | Electric [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	131	116	273	239
WPL [Member] | Electric [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	69	60	140	122
WPL [Member] | Electric [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	108	94	207	184
WPL [Member] | Electric [Member] | Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	38	32	70	61
WPL [Member] | Electric [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	24	13	53	24
WPL [Member] | Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	42	26	165	105
WPL [Member] | Gas [Member] | Retail - residential [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	23	15	97	62
WPL [Member] | Gas [Member] | Retail - commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	13	7	55	33
WPL [Member] | Gas [Member] | Retail - industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	1	4	3
WPL [Member] | Gas [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5	3	9	7
WPL [Member] | Other Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	0	1	1
WPL [Member] | Other Utility [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1	$ 0	$ 1	$ 1

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2023
Income Taxes [Line Items]
State income tax rate, percent	9.80%
Forecast [Member]
Income Taxes [Line Items]
State income tax rate, percent		5.50%

Income Taxes (Schedule Of Effec

Income Taxes (Schedule Of Effective Income Tax Rates) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Effective Tax Rate [Line Items]
Overall income tax rate	2%	(13.00%)	3%	(16.00%)
IPL [Member]
Effective Tax Rate [Line Items]
Overall income tax rate	(16.00%)	(13.00%)	(15.00%)	(15.00%)
WPL [Member]
Effective Tax Rate [Line Items]
Overall income tax rate	18%	(23.00%)	18%	(27.00%)

Income Taxes (Summary Of Tax Cr

Income Taxes (Summary Of Tax Credit Carryforwards) (Details) $ in Millions	Jun. 30, 2022 USD ($)
Federal [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	$ 41
Tax credits, carryforward amount	620
State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	556
IPL [Member] | Federal [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	38
Tax credits, carryforward amount	396
IPL [Member] | State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	10
WPL [Member] | Federal [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	0
Tax credits, carryforward amount	201
WPL [Member] | State [Member]
Carryforwards [Line Items]
Net operating losses, carryforward amount	$ 2

Benefit Plans (Narrative) (Deta

Benefit Plans (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($) shares
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost	$ 11
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost recognized over a weighted average period	1 year
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost recognized over a weighted average period	2 years
IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost	$ 6
WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Unrecognized compensation cost	$ 5
Omnibus Incentive Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Shares included in diluted earnings per share (in shares) | shares	261,301

Benefit Plans (Defined Benefit

Benefit Plans (Defined Benefit Pension And Other Postretirement Benefits Plans) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 3	$ 4	$ 6
Interest cost	9	9	18	17
Expected return on plan assets	(17)	(17)	(34)	(34)
Amortization of actuarial loss	8	9	16	19
Total	2	4	4	8
OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	2
Interest cost	2	1	3	2
Expected return on plan assets	(2)	(1)	(3)	(2)
Amortization of actuarial loss	0	1	1	2
Total	1	2	3	4
IPL [Member] | Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	3	4
Interest cost	4	4	8	8
Expected return on plan assets	(8)	(8)	(16)	(16)
Amortization of actuarial loss	4	4	7	8
Total	1	2	2	4
IPL [Member] | OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1	1
Interest cost	0	0	1	1
Expected return on plan assets	(1)	(1)	(2)	(2)
Amortization of actuarial loss	0	1	0	1
Total	0	1	0	1
WPL [Member] | Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	2
Interest cost	4	4	8	8
Expected return on plan assets	(8)	(7)	(16)	(15)
Amortization of actuarial loss	4	4	8	9
Total	1	2	2	4
WPL [Member] | OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	0	1	1	1
Expected return on plan assets	0	0	0	0
Amortization of actuarial loss	1	0	1	1
Total	$ 1	$ 1	$ 2	$ 2

Benefit Plans (Recognized Compe

Benefit Plans (Recognized Compensation Expense And Income Tax Benefits) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Compensation expense	$ 3	$ 2	$ 7	$ 5
Income tax benefits	1	1	2	2
IPL [Member]
Compensation expense	1	2	4	3
Income tax benefits	0	1	1	1
WPL [Member]
Compensation expense	1	1	3	2
Income tax benefits	$ 0	$ 1	$ 1	$ 1

Benefit Plans (Summary Of Equit

Benefit Plans (Summary Of Equity-based Compensation Plans Grants) (Details)	6 Months Ended
	Jun. 30, 2022 $ / shares shares
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants (in shares/units) | shares	73,762
Weighted average grant date fair value (in dollars per share/unit) | $ / shares	$ 54.45
Performance Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants (in shares/units) | shares	84,277
Weighted average grant date fair value (in dollars per share/unit) | $ / shares	$ 56.97
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants (in shares/units) | shares	76,876
Weighted average grant date fair value (in dollars per share/unit) | $ / shares	$ 56.86

Derivative Instruments (Notiona

Derivative Instruments (Notional Amounts Of Derivative Instruments) (Details) - Commodity [Member] gal in Thousands, T in Thousands, MWh in Thousands, Dekatherms in Thousands	6 Months Ended
	Jun. 30, 2022 Dekatherms MWh T gal
Electricity (MWhs) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	818
Electricity (MWhs) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	495
Electricity (MWhs) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	323
FTRs (MWhs) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	20,382
FTRs (MWhs) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	8,100
FTRs (MWhs) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	12,282
Natural Gas (Dths) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	234,755
Natural Gas (Dths) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	132,019
Natural Gas (Dths) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	102,736
Coal (Tons) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	2,216
Coal (Tons) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	900
Coal (Tons) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Tons) | T	1,316
Diesel Fuel (Gallons) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	1,512
Diesel Fuel (Gallons) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	0
Diesel Fuel (Gallons) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	1,512

Derivative Instruments (Fair Va

Derivative Instruments (Fair Value Of Financial Instruments) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Current derivative assets	$ 217	$ 113
Non-current derivative assets	142	63
Current derivative liabilities	84	8
Non-current derivative liabilities	11	1
IPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	131	48
Non-current derivative assets	76	36
Current derivative liabilities	58	4
Non-current derivative liabilities	9	0
WPL [Member]
Derivatives, Fair Value [Line Items]
Current derivative assets	86	65
Non-current derivative assets	66	27
Current derivative liabilities	26	4
Non-current derivative liabilities	$ 2	$ 1

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value Measurements) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Assets:
Money market fund investments	$ 9	$ 32
Deferred proceeds	244	214
Liabilities:
Long-term debt (incl. current maturities)	7,403	8,330
IPL [Member]
Assets:
Money market fund investments	9	32
Deferred proceeds	244	214
Liabilities:
Long-term debt (incl. current maturities)	3,445	4,124
WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	2,370	2,862
Commodity Contracts [Member]
Assets:
Derivatives	359	176
Liabilities:
Derivatives	95	9
Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	207	84
Liabilities:
Derivatives	67	4
Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	152	92
Liabilities:
Derivatives	28	5
Level 1 [Member]
Assets:
Money market fund investments	9	32
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 1 [Member] | IPL [Member]
Assets:
Money market fund investments	9	32
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 1 [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 1 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	0	0
Liabilities:
Derivatives	0	0
Level 1 [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	0	0
Liabilities:
Derivatives	0	0
Level 1 [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	0	0
Liabilities:
Derivatives	0	0
Level 2 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	7,402	8,329
Level 2 [Member] | IPL [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities:
Long-term debt (incl. current maturities)	3,445	4,124
Level 2 [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	2,370	2,862
Level 2 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	272	146
Liabilities:
Derivatives	80	8
Level 2 [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	138	65
Liabilities:
Derivatives	56	3
Level 2 [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	134	81
Liabilities:
Derivatives	24	5
Level 3 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	244	214
Liabilities:
Long-term debt (incl. current maturities)	1	1
Level 3 [Member] | IPL [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	244	214
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 3 [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	0	0
Level 3 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	87	30
Liabilities:
Derivatives	15	1
Level 3 [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	69	19
Liabilities:
Derivatives	11	1
Level 3 [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	18	11
Liabilities:
Derivatives	4	0
Carrying Amount [Member]
Assets:
Money market fund investments	9	32
Deferred proceeds	244	214
Liabilities:
Long-term debt (incl. current maturities)	7,714	7,368
Carrying Amount [Member] | IPL [Member]
Assets:
Money market fund investments	9	32
Deferred proceeds	244	214
Liabilities:
Long-term debt (incl. current maturities)	3,645	3,643
Carrying Amount [Member] | WPL [Member]
Liabilities:
Long-term debt (incl. current maturities)	2,430	2,429
Carrying Amount [Member] | Commodity Contracts [Member]
Assets:
Derivatives	359	176
Liabilities:
Derivatives	95	9
Carrying Amount [Member] | Commodity Contracts [Member] | IPL [Member]
Assets:
Derivatives	207	84
Liabilities:
Derivatives	67	4
Carrying Amount [Member] | Commodity Contracts [Member] | WPL [Member]
Assets:
Derivatives	152	92
Liabilities:
Derivatives	$ 28	$ 5

Fair Value Measurements (Fair_2

Fair Value Measurements (Fair Value Measurements Using Significant Unobservable Inputs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Commodity Contracts [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 10	$ 15	$ 29	$ 29
Total net gains (losses) included in changes in net assets (realized/unrealized)	(10)	8	(16)	1
Purchases	79	21	79	21
Settlements	(7)	(5)	(20)	(12)
Ending balance	72	39	72	39
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30	(10)	8	(16)	1
Commodity Contracts [Member] | IPL [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	7	14	18	26
Total net gains (losses) included in changes in net assets (realized/unrealized)	(3)	4	(7)	(2)
Purchases	58	16	58	16
Settlements	(4)	(4)	(11)	(10)
Ending balance	58	30	58	30
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30	(3)	4	(8)	(2)
Commodity Contracts [Member] | WPL [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	3	1	11	3
Total net gains (losses) included in changes in net assets (realized/unrealized)	(7)	4	(9)	3
Purchases	21	5	21	5
Settlements	(3)	(1)	(9)	(2)
Ending balance	14	9	14	9
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30	(7)	4	(8)	3
Deferred Proceeds [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	227	107	214	188
Total net gains (losses) included in changes in net assets (realized/unrealized)	0	0	0	0
Purchases	0	0	0	0
Settlements	17	47	30	(34)
Ending balance	244	154	244	154
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30	0	0	0	0
Deferred Proceeds [Member] | IPL [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	227	107	214	188
Total net gains (losses) included in changes in net assets (realized/unrealized)	0	0	0	0
Purchases	0	0	0	0
Settlements	17	47	30	(34)
Ending balance	244	154	244	154
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at June 30	$ 0	$ 0	$ 0	$ 0

Fair Value Measurements (Fair_3

Fair Value Measurements (Fair Value Of Net Derivative Assets (Liabilities)) (Details) - Commodity Contracts [Member] - USD ($) $ in Millions	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	$ 72	$ 10	$ 29	$ 39	$ 15	$ 29
Excluding Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative liabilities	(11)
Fair value, net derivative assets			9
Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	83		20
IPL [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	58	7	18	30	14	26
IPL [Member] | Excluding Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative liabilities	(8)
Fair value, net derivative assets			8
IPL [Member] | Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	66		10
WPL [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	14	$ 3	11	$ 9	$ 1	$ 3
WPL [Member] | Excluding Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative liabilities	(3)
Fair value, net derivative assets			1
WPL [Member] | Financial Transmission Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, net derivative assets	$ 17		$ 10

Commitments And Contingencies_2

Commitments And Contingencies (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,658
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	820
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	809
Capital Purchase Commitment [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	332
Capital Purchase Commitment [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	330
Indemnification Agreement [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum	67
Indemnification Agreement [Member] | Purchased Power [Member]
Commitments and Contingencies [Line Items]
Obligations, maximum	$ 17
Whiting Petroleum Affiliate [Member]
Commitments and Contingencies [Line Items]
Partnership share, percent	6%
Obligations, maximum	$ 58
Credit loss liability	$ 5

Commitments And Contingencies_3

Commitments And Contingencies (Other Purchase Commitments) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($)
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 1,658
Individual commitments incurred	1
IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	820
Individual commitments incurred	1
WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	809
Individual commitments incurred	1
Natural gas [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	1,396
Natural gas [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	691
Natural gas [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	705
Coal [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	148
Coal [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	72
Coal [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	76
Other [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	114
Other [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	57
Other [Member] | WPL [Member]
Commitments and Contingencies [Line Items]
Minimum future commitments	$ 28

Commitments And Contingencies_4

Commitments And Contingencies (MPG Site Estimated Future Costs And Recorded Liabilities) (Details) - Natural Gas Processing Plant [Member] $ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($)
Commitments and Contingencies [Line Items]
Current and non-current environmental liabilities	$ 12
IPL [Member]
Commitments and Contingencies [Line Items]
Current and non-current environmental liabilities	8
Minimum [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	9
Minimum [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	6
Maximum [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	25
Maximum [Member] | IPL [Member]
Commitments and Contingencies [Line Items]
Range of estimated future costs	$ 19

Segments Of Business (Schedule

Segments Of Business (Schedule Of Segments Of Business) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Revenues	$ 943	$ 817	$ 2,012	$ 1,718
Operating income (loss)	212	176	460	374
Net income attributable to common shareowners	159	144	351	315
Net income	159	146	351	320
IPL [Member]
Segment Reporting Information [Line Items]
Revenues	506	455	1,056	944
Operating income (loss)	109	111	218	214
Net income attributable to common shareowners	87	86	173	165
Net income	87	88	173	170
WPL [Member]
Segment Reporting Information [Line Items]
Revenues	413	341	909	736
Operating income (loss)	95	55	227	145
Net income	63	38	156	122
Electric [Member]
Segment Reporting Information [Line Items]
Revenues	812	717	1,586	1,418
Operating income (loss)	195	164	376	311
Electric [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	442	402	843	788
Operating income (loss)	104	107	179	179
Electric [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	370	315	743	630
Operating income (loss)	91	57	197	132
Gas [Member]
Segment Reporting Information [Line Items]
Revenues	94	69	356	239
Operating income (loss)	8	3	65	47
Gas [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	52	43	191	134
Operating income (loss)	4	3	36	33
Gas [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	42	26	165	105
Operating income (loss)	4	0	29	14
Other Utility [Member]
Segment Reporting Information [Line Items]
Revenues	13	10	23	23
Operating income (loss)	1	(1)	4	1
Other Utility [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	12	10	22	22
Operating income (loss)	1	1	3	2
Other Utility [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	1	0	1	1
Operating income (loss)	0	(2)	1	(1)
Utility Business [Member]
Segment Reporting Information [Line Items]
Revenues	919	796	1,965	1,680
Operating income (loss)	204	166	445	359
Net income attributable to common shareowners	150	124	329	287
ATC Holdings, Non-Utility, Parent and Other [Member]
Segment Reporting Information [Line Items]
Revenues	24	21	47	38
Operating income (loss)	8	10	15	15
Net income attributable to common shareowners	$ 9	$ 20	$ 22	$ 28

Related Parties (Narrative) (De

Related Parties (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
WPL [Member] | ATC LLC [Member] | WPL Owed ATC LLC [Member] | Equity Method Investee [Member]
Related Party Transactions [Line Items]
Net amounts owed	$ 9	$ 10

Related Parties (Service Agreem

Related Parties (Service Agreements) (Details) - Corporate Services [Member] - Subsidiary of Common Parent [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Corporate Services Billings [Member] | IPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 51	$ 48	$ 91	$ 88
Corporate Services Billings [Member] | WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	42	41	78	76
Sales Credited [Member] | IPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	0	4	0	5
Sales Credited [Member] | WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	13	6	31	7
Purchases Billed [Member] | IPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	129	99	223	242
Purchases Billed [Member] | WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 39	$ 21	$ 61	$ 47

Related Parties (Net Intercompa

Related Parties (Net Intercompany Payables) (Details) - Subsidiary of Common Parent [Member] - Corporate Services [Member] - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
IPL [Member]
Related Party Transactions [Line Items]
Net amounts owed	$ 112	$ 110
WPL [Member]
Related Party Transactions [Line Items]
Net amounts owed	$ 63	$ 83

Related Parties (Amounts Billed

Related Parties (Amounts Billed Between Parties) (Details) - ATC LLC [Member] - Equity Method Investee [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
ATC Billings To WPL [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 35	$ 30	$ 69	$ 62
WPL Billings To ATC [Member]
Related Party Transactions [Line Items]
Amounts billed between related parties	$ 5	$ 6	$ 8	$ 9