0000001 - Document - Cover link:presentationLink link:calculationLink link:definitionLink 9952151 - Statement - CONSOLIDATED STATEMENTS OF INCOME link:presentationLink link:calculationLink link:definitionLink 9952152 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME link:presentationLink link:calculationLink link:definitionLink 9952153 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 9952154 - Statement - CONSOLIDATED BALANCE SHEETS link:presentationLink link:calculationLink link:definitionLink 9952155 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) link:presentationLink link:calculationLink link:definitionLink 9952156 - Statement - CONSOLIDATED STATEMENTS OF COMMON SHAREHOLDER’S EQUITY Statement link:presentationLink link:calculationLink link:definitionLink 9952157 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS link:presentationLink link:calculationLink link:definitionLink 9952158 - Disclosure - Summary of Consolidation and Significant Accounting Policy link:presentationLink link:calculationLink link:definitionLink 9952159 - Disclosure - New Accounting Pronouncements link:presentationLink link:calculationLink link:definitionLink 9952160 - Disclosure - Revenue link:presentationLink link:calculationLink link:definitionLink 9952161 - Disclosure - Accounting for Derivative Instruments and Hedging Activities link:presentationLink link:calculationLink link:definitionLink 9952162 - Disclosure - Fair Value Measurements link:presentationLink link:calculationLink link:definitionLink 9952163 - Disclosure - Retirement Benefits link:presentationLink link:calculationLink link:definitionLink 9952164 - Disclosure - Regulation and Rates link:presentationLink link:calculationLink link:definitionLink 9952165 - Disclosure - Commitments and Contingencies link:presentationLink link:calculationLink link:definitionLink 9952166 - Disclosure - Leases link:presentationLink link:calculationLink link:definitionLink 9952167 - Disclosure - Other link:presentationLink link:calculationLink link:definitionLink 9952168 - Disclosure - Segment Information link:presentationLink link:calculationLink link:definitionLink 9955511 - Disclosure - Summary of Consolidation and Significant Accounting Policy (Policies) link:presentationLink link:calculationLink link:definitionLink 9955512 - Disclosure - Summary of Consolidation and Significant Accounting Policy (Tables) link:presentationLink link:calculationLink link:definitionLink 9955513 - Disclosure - Revenue (Tables) link:presentationLink link:calculationLink link:definitionLink 9955514 - Disclosure - Accounting for Derivative Instruments and Hedging Activities (Tables) link:presentationLink link:calculationLink link:definitionLink 9955515 - Disclosure - Fair Value Measurements (Tables) link:presentationLink link:calculationLink link:definitionLink 9955516 - Disclosure - Retirement Benefits (Tables) link:presentationLink link:calculationLink link:definitionLink 9955517 - Disclosure - Regulation and Rates (Tables) link:presentationLink link:calculationLink link:definitionLink 9955518 - Disclosure - Leases (Tables) link:presentationLink link:calculationLink link:definitionLink 9955519 - Disclosure - Segment Information (Tables) link:presentationLink link:calculationLink link:definitionLink 9955520 - Disclosure - Summary of Consolidation and Significant Accounting Policy - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955521 - Disclosure - Summary of Consolidation and Significant Accounting Policy - Allowance for Credit Loss (Details) link:presentationLink link:calculationLink link:definitionLink 9955522 - Disclosure - Revenue - Disaggregation of Revenue (Details) link:presentationLink link:calculationLink link:definitionLink 9955523 - Disclosure - Revenue - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955524 - Disclosure - Revenue - Performance Obligations (Details) link:presentationLink link:calculationLink link:definitionLink 9955524 - Disclosure - Revenue - Performance Obligations (Details) link:presentationLink link:calculationLink link:definitionLink 9955525 - Disclosure - Accounting for Derivative Instruments and Hedging Activities - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955526 - Disclosure - Accounting for Derivative Instruments and Hedging Activities - Derivative Assets and Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 9955527 - Disclosure - Accounting for Derivative Instruments and Hedging Activities - Net Amount of Derivatives Reported in the Statement of Financial Position (Details) link:presentationLink link:calculationLink link:definitionLink 9955528 - Disclosure - Accounting for Derivative Instruments and Hedging Activities - Contractual Contingent Liability (Details) link:presentationLink link:calculationLink link:definitionLink 9955529 - Disclosure - Fair Value Measurements - Debt at at Carrying and Fair Value (Details) link:presentationLink link:calculationLink link:definitionLink 9955530 - Disclosure - Fair Value Measurements - Assets and Liabilities (Details) link:presentationLink link:calculationLink link:definitionLink 9955531 - Disclosure - Fair Value Measurements - Level 3 Rollforward (Details) link:presentationLink link:calculationLink link:definitionLink 9955532 - Disclosure - Fair Value Measurements - Valuation Techniques for Measurement with Unobservable Inputs (Details) link:presentationLink link:calculationLink link:definitionLink 9955533 - Disclosure - Retirement Benefits - Net Periodic Benefit Cost (Details) link:presentationLink link:calculationLink link:definitionLink 9955534 - Disclosure - Retirement Benefits - Activity (Details) link:presentationLink link:calculationLink link:definitionLink 9955535 - Disclosure - Regulation and Rates - General Rate Case (Details) link:presentationLink link:calculationLink link:definitionLink 9955536 - Disclosure - Regulation and Rates - Colstrip Adjustment Rider (Details) link:presentationLink link:calculationLink link:definitionLink 9955537 - Disclosure - Regulation and Rates - Climate Commitment Act Deferral and Natural Gas (Details) link:presentationLink link:calculationLink link:definitionLink 9955538 - Disclosure - Regulation and Rates - Schedule of Power Cost Adjustment Mechanism (Details) link:presentationLink link:calculationLink link:definitionLink 9955539 - Disclosure - Regulation and Rates - Power Cost Adjustment Mechanism (Details) link:presentationLink link:calculationLink link:definitionLink 9955540 - Disclosure - Regulation and Rates - Purchased Gas Adjustment Mechanism (Details) link:presentationLink link:calculationLink link:definitionLink 9955541 - Disclosure - Regulation and Rates - Schedule of Purchased Gas Adjustment Mechanism (Details) link:presentationLink link:calculationLink link:definitionLink 9955542 - Disclosure - Commitments and Contingencies (Details) link:presentationLink link:calculationLink link:definitionLink 9955543 - Disclosure - Leases (Details) link:presentationLink link:calculationLink link:definitionLink 9955544 - Disclosure - Leases - Supplemental balance sheet information related to leases (Details) link:presentationLink link:calculationLink link:definitionLink 9955545 - Disclosure - Other - Narrative (Details) link:presentationLink link:calculationLink link:definitionLink 9955546 - Disclosure - Segment Information (Details) link:presentationLink link:calculationLink link:definitionLink