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Segments Of Business | 9 Months Ended
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Sep. 30, 2021
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 September 30, 2021 |  |  |  |  |  |  |  |  |  |  |
Revenues | $939 |  | $50 |  | $13 |  | $1,002 |  | $22 |  | $1,024
Operating income (loss) | 290 |  | (5) |  | (5) |  | 280 |  | 9 |  | 289
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 250 |  | 6 |  | 256
Three Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |
Revenues | $852 |  | $42 |  | $10 |  | $904 |  | $16 |  | $920
Operating income (loss) | 251 |  | (1) |  | 1 |  | 251 |  | 21 |  | 272
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 221 |  | 25 |  | 246
Alliant Energy |  |  |  |  |  |  |  |  | ATC Holdings, |  | Alliant
| Utility |  | Non-Utility, |  | Energy
| Electric |  | Gas |  | Other |  | Total |  | Parent and Other |  | Consolidated
| (in millions)
Nine Months Ended September 30, 2021 |  |  |  |  |  |  |  |  |  |  |
Revenues | $2,357 |  | $289 |  | $36 |  | $2,682 |  | $60 |  | $2,742
Operating income (loss) | 601 |  | 42 |  | (4) |  | 639 |  | 24 |  | 663
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 537 |  | 34 |  | 571
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |
Revenues | $2,257 |  | $253 |  | $32 |  | $2,542 |  | $57 |  | $2,599
Operating income | 549 |  | 48 |  | 5 |  | 602 |  | 26 |  | 628
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 510 |  | 40 |  | 550
IPL | Electric |  | Gas |  | Other |  | Total
| (in millions)
Three Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $555 |  | $31 |  | $13 |  | $599
Operating income (loss) | 186 |  | (3) |  | (3) |  | 180
Net income available for common stock |  |  |  |  |  |  | 157
Three Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $519 |  | $24 |  | $10 |  | $553
Operating income | 159 |  | 1 |  | 2 |  | 162
Net income available for common stock |  |  |  |  |  |  | 148
Nine Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $1,343 |  | $165 |  | $35 |  | $1,543
Operating income (loss) | 365 |  | 30 |  | (1) |  | 394
Net income available for common stock |  |  |  |  |  |  | 322
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $1,332 |  | $141 |  | $31 |  | $1,504
Operating income | 308 |  | 34 |  | 5 |  | 347
Net income available for common stock |  |  |  |  |  |  | 290
WPL | Electric |  | Gas |  | Other |  | Total
| (in millions)
Three Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $384 |  | $19 |  | $— |  | $403
Operating income (loss) | 104 |  | (2) |  | (2) |  | 100
Net income |  |  |  |  |  |  | 93
Three Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $333 |  | $18 |  | $— |  | $351
Operating income (loss) | 92 |  | (2) |  | (1) |  | 89
Net income |  |  |  |  |  |  | 73
Nine Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $1,014 |  | $124 |  | $1 |  | $1,139
Operating income (loss) | 236 |  | 12 |  | (3) |  | 245
Net income |  |  |  |  |  |  | 215
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $925 |  | $112 |  | $1 |  | $1,038
Operating income | 241 |  | 14 |  | — |  | 255
Net income |  |  |  |  |  |  | 220
IPL [Member] |
Segment Reporting Information [Line Items] |
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 September 30, 2021 |  |  |  |  |  |  |  |  |  |  |
Revenues | $939 |  | $50 |  | $13 |  | $1,002 |  | $22 |  | $1,024
Operating income (loss) | 290 |  | (5) |  | (5) |  | 280 |  | 9 |  | 289
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 250 |  | 6 |  | 256
Three Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |
Revenues | $852 |  | $42 |  | $10 |  | $904 |  | $16 |  | $920
Operating income (loss) | 251 |  | (1) |  | 1 |  | 251 |  | 21 |  | 272
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 221 |  | 25 |  | 246
Alliant Energy |  |  |  |  |  |  |  |  | ATC Holdings, |  | Alliant
| Utility |  | Non-Utility, |  | Energy
| Electric |  | Gas |  | Other |  | Total |  | Parent and Other |  | Consolidated
| (in millions)
Nine Months Ended September 30, 2021 |  |  |  |  |  |  |  |  |  |  |
Revenues | $2,357 |  | $289 |  | $36 |  | $2,682 |  | $60 |  | $2,742
Operating income (loss) | 601 |  | 42 |  | (4) |  | 639 |  | 24 |  | 663
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 537 |  | 34 |  | 571
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |
Revenues | $2,257 |  | $253 |  | $32 |  | $2,542 |  | $57 |  | $2,599
Operating income | 549 |  | 48 |  | 5 |  | 602 |  | 26 |  | 628
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 510 |  | 40 |  | 550
IPL | Electric |  | Gas |  | Other |  | Total
| (in millions)
Three Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $555 |  | $31 |  | $13 |  | $599
Operating income (loss) | 186 |  | (3) |  | (3) |  | 180
Net income available for common stock |  |  |  |  |  |  | 157
Three Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $519 |  | $24 |  | $10 |  | $553
Operating income | 159 |  | 1 |  | 2 |  | 162
Net income available for common stock |  |  |  |  |  |  | 148
Nine Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $1,343 |  | $165 |  | $35 |  | $1,543
Operating income (loss) | 365 |  | 30 |  | (1) |  | 394
Net income available for common stock |  |  |  |  |  |  | 322
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $1,332 |  | $141 |  | $31 |  | $1,504
Operating income | 308 |  | 34 |  | 5 |  | 347
Net income available for common stock |  |  |  |  |  |  | 290
WPL | Electric |  | Gas |  | Other |  | Total
| (in millions)
Three Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $384 |  | $19 |  | $— |  | $403
Operating income (loss) | 104 |  | (2) |  | (2) |  | 100
Net income |  |  |  |  |  |  | 93
Three Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $333 |  | $18 |  | $— |  | $351
Operating income (loss) | 92 |  | (2) |  | (1) |  | 89
Net income |  |  |  |  |  |  | 73
Nine Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $1,014 |  | $124 |  | $1 |  | $1,139
Operating income (loss) | 236 |  | 12 |  | (3) |  | 245
Net income |  |  |  |  |  |  | 215
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $925 |  | $112 |  | $1 |  | $1,038
Operating income | 241 |  | 14 |  | — |  | 255
Net income |  |  |  |  |  |  | 220
WPL [Member] |
Segment Reporting Information [Line Items] |
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 September 30, 2021 |  |  |  |  |  |  |  |  |  |  |
Revenues | $939 |  | $50 |  | $13 |  | $1,002 |  | $22 |  | $1,024
Operating income (loss) | 290 |  | (5) |  | (5) |  | 280 |  | 9 |  | 289
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 250 |  | 6 |  | 256
Three Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |
Revenues | $852 |  | $42 |  | $10 |  | $904 |  | $16 |  | $920
Operating income (loss) | 251 |  | (1) |  | 1 |  | 251 |  | 21 |  | 272
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 221 |  | 25 |  | 246
Alliant Energy |  |  |  |  |  |  |  |  | ATC Holdings, |  | Alliant
| Utility |  | Non-Utility, |  | Energy
| Electric |  | Gas |  | Other |  | Total |  | Parent and Other |  | Consolidated
| (in millions)
Nine Months Ended September 30, 2021 |  |  |  |  |  |  |  |  |  |  |
Revenues | $2,357 |  | $289 |  | $36 |  | $2,682 |  | $60 |  | $2,742
Operating income (loss) | 601 |  | 42 |  | (4) |  | 639 |  | 24 |  | 663
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 537 |  | 34 |  | 571
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |
Revenues | $2,257 |  | $253 |  | $32 |  | $2,542 |  | $57 |  | $2,599
Operating income | 549 |  | 48 |  | 5 |  | 602 |  | 26 |  | 628
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 510 |  | 40 |  | 550
IPL | Electric |  | Gas |  | Other |  | Total
| (in millions)
Three Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $555 |  | $31 |  | $13 |  | $599
Operating income (loss) | 186 |  | (3) |  | (3) |  | 180
Net income available for common stock |  |  |  |  |  |  | 157
Three Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $519 |  | $24 |  | $10 |  | $553
Operating income | 159 |  | 1 |  | 2 |  | 162
Net income available for common stock |  |  |  |  |  |  | 148
Nine Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $1,343 |  | $165 |  | $35 |  | $1,543
Operating income (loss) | 365 |  | 30 |  | (1) |  | 394
Net income available for common stock |  |  |  |  |  |  | 322
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $1,332 |  | $141 |  | $31 |  | $1,504
Operating income | 308 |  | 34 |  | 5 |  | 347
Net income available for common stock |  |  |  |  |  |  | 290
WPL | Electric |  | Gas |  | Other |  | Total
| (in millions)
Three Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $384 |  | $19 |  | $— |  | $403
Operating income (loss) | 104 |  | (2) |  | (2) |  | 100
Net income |  |  |  |  |  |  | 93
Three Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $333 |  | $18 |  | $— |  | $351
Operating income (loss) | 92 |  | (2) |  | (1) |  | 89
Net income |  |  |  |  |  |  | 73
Nine Months Ended September 30, 2021 |  |  |  |  |  |  |
Revenues | $1,014 |  | $124 |  | $1 |  | $1,139
Operating income (loss) | 236 |  | 12 |  | (3) |  | 245
Net income |  |  |  |  |  |  | 215
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues | $925 |  | $112 |  | $1 |  | $1,038
Operating income | 241 |  | 14 |  | — |  | 255
Net income |  |  |  |  |  |  | 220

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- Definition The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 31 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8924-108599 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 34 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8981-108599 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8721-108599 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 40 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9031-108599 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 26 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8844-108599 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 41 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9038-108599 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 42 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9054-108599 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8657-108599 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8721-108599 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -URI http://asc.fasb.org/topic&trid=2134510 + Details
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