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Summary of Significant Accounting Policies AFUDC (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Allowance for Funds Used During Construction |  |  |
AFUDC - Debt | $ 5.9 | $ 6.9 | $ 4.9
AFUDC – Equity | $ 14.4 | 15.2 | 11.4
WE |  |  |
Allowance for Funds Used During Construction |  |  |
Percentage of retail jurisdictional construction work in progress expenditure subject to public utilities allowance for funds used during construction calculation | 50.00% |  |
AFUDC - Debt | $ 1.5 | 1.5 | 1.2
AFUDC – Equity | $ 3.7 | 3.9 | 3.1
WPS |  |  |
Allowance for Funds Used During Construction |  |  |
Percentage of retail jurisdictional construction work in progress expenditure subject to public utilities allowance for funds used during construction calculation | 50.00% |  |
AFUDC - Debt | $ 2.4 | 1.9 | 1.6
AFUDC – Equity | $ 5.7 | 4.6 | 4.1
WG |  |  |
Allowance for Funds Used During Construction |  |  |
Percentage of retail jurisdictional construction work in progress expenditure subject to public utilities allowance for funds used during construction calculation | 50.00% |  |
AFUDC - Debt | $ 0.5 | 0.2 | 0.3
AFUDC – Equity | $ 1.3 | 0.6 | 0.9
UMERC |  |  |
Allowance for Funds Used During Construction |  |  |
Percentage of retail jurisdictional construction work in progress expenditure subject to public utilities allowance for funds used during construction calculation | 50.00% |  |
AFUDC - Debt | $ 1.3 | 2.4 | 0.1
AFUDC – Equity | $ 3.3 | 5.4 | 0.2
WBS |  |  |
Allowance for Funds Used During Construction |  |  |
Percentage of retail jurisdictional construction work in progress expenditure subject to public utilities allowance for funds used during construction calculation | 50.00% |  |
AFUDC - Debt | $ 0.1 | 0.2 | 1.1
AFUDC – Equity | 0.2 | 0.6 | 3.0
Other |  |  |
Allowance for Funds Used During Construction |  |  |
AFUDC - Debt | 0.1 | 0.7 | 0.6
AFUDC – Equity | $ 0.2 | $ 0.1 | $ 0.1
Retail operations | WE |  |  |
Allowance for Funds Used During Construction |  |  |
Average AFUDC rate (as a percent) | 8.45% |  |
Retail operations | WPS |  |  |
Allowance for Funds Used During Construction |  |  |
Average AFUDC rate (as a percent) | 7.72% |  |
Retail operations | WG |  |  |
Allowance for Funds Used During Construction |  |  |
Average AFUDC rate (as a percent) | 8.33% |  |
Retail operations | UMERC |  |  |
Allowance for Funds Used During Construction |  |  |
Average AFUDC rate (as a percent) | 6.28% |  |
Retail operations | WBS |  |  |
Allowance for Funds Used During Construction |  |  |
Average AFUDC rate (as a percent) | 7.72% |  |
Wholesale operations | WE |  |  |
Allowance for Funds Used During Construction |  |  |
Average AFUDC rate (as a percent) | 5.11% |  |
Wholesale operations | WPS |  |  |
Allowance for Funds Used During Construction |  |  |
Average AFUDC rate (as a percent) | 2.58% |  |

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- Definition The component of the allowance for funds used during construction during the period based on an assumed rate of return on equity funds used in financing the construction of regulated assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 835 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501662&loc=d3e56162-110433 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 835 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501569&loc=d3e55921-110430 + Details
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- Definition Effective rate, including composite rate, of cost of financing additions to qualifying regulated assets, commonly called allowance for funds used during construction. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 835 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501662&loc=d3e56162-110433 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 835 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501569&loc=d3e55921-110430 + Details
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