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Valuation And Qualifying Accounts and Reserves (Details) - Accumulated Provision for Uncollectible Accounts [Member] - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |
Beginning Balance | $ 7.0 | $ 10.0 | $ 12.0
Charged to Expense | 25.0 | 17.0 | 21.0
Charged to Other Accounts | 9.0 | 2.0 | 1.0
Deductions | 23.0 | 22.0 | 24.0
Ending Balance | 18.0 | 7.0 | 10.0
IPL [Member] |  |  |
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |
Beginning Balance | 1.0 | 3.0 | 1.0
Charged to Expense | 18.0 | 16.0 | 21.0
Charged to Other Accounts | 0.0 | 0.0 | 0.0
Deductions | 18.0 | 18.0 | 19.0
Ending Balance | 1.0 | 1.0 | 3.0
WPL [Member] |  |  |
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] |  |  |
Beginning Balance | 6.0 | 7.0 | 11.0
Charged to Expense | 7.0 | 1.0 | 0.0
Charged to Other Accounts | 9.0 | 2.0 | 1.0
Deductions | 5.0 | 4.0 | 5.0
Ending Balance | $ 17.0 | $ 6.0 | $ 7.0

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- Definition Amount of valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column B)) -URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column E)) -URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690 + Details
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- Definition Amount of increase in valuation and qualifying accounts and reserves from charge to cost and expense. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column C)(1)) -URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690 + Details
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- Definition Amount of increase in valuation and qualifying accounts and reserves from charge to accounts other than cost and expense. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column C)(2)) -URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690 + Details
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- Definition Amount of decrease in valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column D)) -URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690 + Details
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