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Leases (Operating Leases) (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020
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Leases [Line Items] |  |
Operating leases assets, Property, plant and equipment, net | $ 14 | $ 15
Operating leases liabilities, Other current liabilities | 2 | 2
Operating leases liabilities, Other liabilities | 12 | 13
Operating leases liabilities, Total | $ 14 | $ 15
Operating leases, Weighted average remaining lease term | 9 years | 10 years
Operating leases, Weighted average discount rate, percent | 4.00% | 4.00%
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List] | Other | Other
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] | Other | Other
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] | Other Assets | Other Assets
IPL [Member] |  |
Leases [Line Items] |  |
Operating leases assets, Property, plant and equipment, net | $ 9 | $ 9
Operating leases liabilities, Other current liabilities | 1 | 1
Operating leases liabilities, Other liabilities | 8 | 8
Operating leases liabilities, Total | $ 9 | $ 9
Operating leases, Weighted average remaining lease term | 11 years | 11 years
Operating leases, Weighted average discount rate, percent | 4.00% | 4.00%
WPL [Member] |  |
Leases [Line Items] |  |
Operating leases assets, Property, plant and equipment, net | $ 5 | $ 6
Operating leases liabilities, Other current liabilities | 1 | 1
Operating leases liabilities, Other liabilities | 4 | 5
Operating leases liabilities, Total | $ 5 | $ 6
Operating leases, Weighted average remaining lease term | 8 years | 9 years
Operating leases, Weighted average discount rate, percent | 4.00% | 4.00%

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- Definition Discount rate used by lessee to determine present value of operating lease payments. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
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- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
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- Definition Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(3) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980 + Details
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