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Leases (Operating Leases) (Details) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2019 USD ($) | Jun. 30, 2019 USD ($)
Leases [Line Items] |  |
Operating leases assets, Property, plant and equipment, net | $ 17 | $ 17
Operating leases liabilities, Other current liabilities | 2 | 2
Operating leases liabilities, Other liabilities | 15 | 15
Operating leases liabilities, Total | $ 17 | $ 17
Operating Lease, Weighted Average Remaining Lease Term | 11 years | 11 years
Operating leases, Weighted average discount rate, percent | 4.00% | 4.00%
Operating leases, Cost | $ 0 | $ 1
IPL [Member] |  |
Leases [Line Items] |  |
Operating leases assets, Property, plant and equipment, net | 10 | 10
Operating leases liabilities, Other current liabilities | 1 | 1
Operating leases liabilities, Other liabilities | 9 | 9
Operating leases liabilities, Total | $ 10 | $ 10
Operating Lease, Weighted Average Remaining Lease Term | 13 years | 13 years
Operating leases, Weighted average discount rate, percent | 4.00% | 4.00%
Operating leases, Cost | $ 0 | $ 0
WPL [Member] |  |
Leases [Line Items] |  |
Operating leases assets, Property, plant and equipment, net | 7 | 7
Operating leases liabilities, Other current liabilities | 1 | 1
Operating leases liabilities, Other liabilities | 6 | 6
Operating leases liabilities, Total | $ 7 | $ 7
Operating Lease, Weighted Average Remaining Lease Term | 10 years | 10 years
Operating leases, Weighted average discount rate, percent | 4.00% | 4.00%
Operating leases, Cost | $ 0 | $ 0

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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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=77888426&loc=SL77918673-209980 + Details
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- Definition Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability. + 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=77888399&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 (b) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980 + 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=77888419&loc=SL77918627-209977 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as current. + 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=77888419&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=77888419&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=77888419&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=77888399&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=77888426&loc=SL77918686-209980 + Details
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