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Regulatory Matters: Rate Review (Details) $ in Millions | Oct. 08, 2021 USD ($) mi | Oct. 05, 2021 USD ($) mi | Jul. 06, 2021 | Jun. 01, 2021 USD ($) mi | Mar. 01, 2021 USD ($) mi | Sep. 11, 2020
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Settlement agreement reached with CPUC Staff and various intervenors, subject to the review and approval by an Administrative Law Judge and the CPUC. | Colorado Public Utilities Commission (CPUC) | Colorado Gas | Subsequent Event |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments | mi |  | 7,000 |  |  |  |
Public Utilities, Requested Rate Increase (Decrease), Amount |  | $ 6.5 |  |  |  |
Public Utilities, Approved Equity Capital Structure, Percentage |  | 50.30% |  |  |  |
Public Utilities, Approved Debt Capital Structure, Percentage |  | 49.70% |  |  |  |
Public Utilities, Requested Return on Equity, Percentage |  | 9.20% |  |  |  |
Rate Review Filed with the Regulatory Agency | Colorado Public Utilities Commission (CPUC) | Colorado Gas |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Public Utilities, Requested Term Extension of System Safety and Integrity Rider |  |  |  |  |  | 5 years
Rate Review Filed with the Regulatory Agency | Iowa Utilities Board (IUB) | Iowa Gas |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments | mi |  |  |  | 5,000 |  |
Public Utilities, Requested Rate Increase (Decrease), Amount |  |  |  | $ 8.3 |  |
Public Utilities, Requested Equity Capital Structure, Percentage |  |  |  | 50.00% |  |
Public Utilities, Requested Debt Capital Structure, Percentage |  |  |  | 50.00% |  |
Public Utilities, Requested Return on Equity, Percentage |  |  |  | 10.15% |  |
Public Utilities Amount of System Safety and Integrity Rider Moved to Base Rates Requested |  |  |  | $ 2.2 |  |
Public Utilities, Number of Days After Filing a Rate Review the Interim Rates May Be Implemented |  |  |  | 10 days |  |
Rate Review Approved by Regulatory Agency | Colorado Public Utilities Commission (CPUC) | Colorado Gas |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Public Utilities, Term Extension of System Safety and Integrity Rider |  |  | 3 years |  |  |
Rate Review Approved by Regulatory Agency | Nebraska Publc Service Commission (NPSC) | Nebraska Gas |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Public Utilities, Approved Return on Equity, Percentage |  |  |  |  | 9.50% |
Public Utilities, Approved Equity Capital Structure, Percentage |  |  |  |  | 50.00% |
Public Utilities, Approved Debt Capital Structure, Percentage |  |  |  |  | 50.00% |
Public Utilities Amount of System Safety and Integrity Rider Moved to Base Rates Requested |  |  |  |  | $ 4.6 |
Public Utilities, Approved Rate Increase (Decrease), Amount |  |  |  |  | $ 6.5 |
Global Settlement agreement with KCC Staff and various intervenors for a general rate increase and renewal of its safety and integrity rider. | Kansas Corporation Commission (KCC) | Kansas Gas | Subsequent Event |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments | mi | 4,600 |  |  |  |  |
Public Utilities, Term Extension of System Safety and Integrity Rider | 5 years |  |  |  |  |
Public Utilities Amount of System Safety and Integrity Rider Moved to Base Rates Requested | $ 6.6 |  |  |  |  |
Approval Recevied from Regulatory Agency | Nebraska Publc Service Commission (NPSC) | Nebraska Gas |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |
Public Utilities - Length of Natural Gas Pipeline to Receive Infrastructure Investments | mi |  |  |  |  | 13,000 |
Public Utilities, Term Extension of System Safety and Integrity Rider |  |  |  |  | 5 years |

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