3.20.2 html 941 478 1 true 221 0 false 20 false false R1.htm 0001001 - Document - Cover Page Sheet http://www.avangrid.com/role/CoverPage Cover Page Cover 1 false false R2.htm 1001002 - Statement - Condensed Consolidated Statements of Income (unaudited) Sheet http://www.avangrid.com/role/CondensedConsolidatedStatementsofIncomeunaudited Condensed Consolidated Statements of Income (unaudited) Statements 2 false false R3.htm 1002003 - Statement - Condensed Consolidated Statements of Comprehensive Income (unaudited) Sheet http://www.avangrid.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunaudited Condensed Consolidated Statements of Comprehensive Income (unaudited) Statements 3 false false R4.htm 1003004 - Statement - Condensed Consolidated Statements of Comprehensive Income (unaudited) (Parenthetical) Sheet http://www.avangrid.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeunauditedParenthetical Condensed Consolidated Statements of Comprehensive Income (unaudited) (Parenthetical) Statements 4 false false R5.htm 1004005 - Statement - Condensed Consolidated Balance Sheets (unaudited) Sheet http://www.avangrid.com/role/CondensedConsolidatedBalanceSheetsunaudited Condensed Consolidated Balance Sheets (unaudited) Statements 5 false false R6.htm 1005006 - Statement - Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) Sheet http://www.avangrid.com/role/CondensedConsolidatedBalanceSheetsunauditedParenthetical Condensed Consolidated Balance Sheets (unaudited) (Parenthetical) Statements 6 false false R7.htm 1006007 - Statement - Condensed Consolidated Statements of Cash Flows (unaudited) Sheet http://www.avangrid.com/role/CondensedConsolidatedStatementsofCashFlowsunaudited Condensed Consolidated Statements of Cash Flows (unaudited) Statements 7 false false R8.htm 1007008 - Statement - Condensed Consolidated Statements of Changes in Equity (unaudited) Sheet http://www.avangrid.com/role/CondensedConsolidatedStatementsofChangesinEquityunaudited Condensed Consolidated Statements of Changes in Equity (unaudited) Statements 8 false false R9.htm 1008009 - Statement - Condensed Consolidated Statements of Changes in Equity (unaudited) (Parenthetical) Sheet http://www.avangrid.com/role/CondensedConsolidatedStatementsofChangesinEquityunauditedParenthetical Condensed Consolidated Statements of Changes in Equity (unaudited) (Parenthetical) Statements 9 false false R10.htm 2101101 - Disclosure - Background and Nature of Operations Sheet http://www.avangrid.com/role/BackgroundandNatureofOperations Background and Nature of Operations Notes 10 false false R11.htm 2103102 - Disclosure - Basis of Presentation Sheet http://www.avangrid.com/role/BasisofPresentation Basis of Presentation Notes 11 false false R12.htm 2104103 - Disclosure - Significant Accounting Policies and New Accounting Pronouncements Sheet http://www.avangrid.com/role/SignificantAccountingPoliciesandNewAccountingPronouncements Significant Accounting Policies and New Accounting Pronouncements Notes 12 false false R13.htm 2107104 - Disclosure - Revenue Sheet http://www.avangrid.com/role/Revenue Revenue Notes 13 false false R14.htm 2113105 - Disclosure - Regulatory Assets and Liabilities Sheet http://www.avangrid.com/role/RegulatoryAssetsandLiabilities Regulatory Assets and Liabilities Notes 14 false false R15.htm 2119106 - Disclosure - Fair Value of Financial Instruments and Fair Value Measurements Sheet http://www.avangrid.com/role/FairValueofFinancialInstrumentsandFairValueMeasurements Fair Value of Financial Instruments and Fair Value Measurements Notes 15 false false R16.htm 2126107 - Disclosure - Derivative Instruments and Hedging Sheet http://www.avangrid.com/role/DerivativeInstrumentsandHedging Derivative Instruments and Hedging Notes 16 false false R17.htm 2135108 - Disclosure - Contingencies Sheet http://www.avangrid.com/role/Contingencies Contingencies Notes 17 false false R18.htm 2137109 - Disclosure - Environmental Liabilities Sheet http://www.avangrid.com/role/EnvironmentalLiabilities Environmental Liabilities Notes 18 false false R19.htm 2139110 - Disclosure - Post-retirement and Similar Obligations Sheet http://www.avangrid.com/role/PostretirementandSimilarObligations Post-retirement and Similar Obligations Notes 19 false false R20.htm 2143111 - Disclosure - Equity Sheet http://www.avangrid.com/role/Equity Equity Notes 20 false false R21.htm 2147112 - Disclosure - Earnings Per Share Sheet http://www.avangrid.com/role/EarningsPerShare Earnings Per Share Notes 21 false false R22.htm 2150113 - Disclosure - Segment Information Sheet http://www.avangrid.com/role/SegmentInformation Segment Information Notes 22 false false R23.htm 2155114 - Disclosure - Related Party Transactions Sheet http://www.avangrid.com/role/RelatedPartyTransactions Related Party Transactions Notes 23 false false R24.htm 2160115 - Disclosure - Other Financial Statement Items Sheet http://www.avangrid.com/role/OtherFinancialStatementItems Other Financial Statement Items Notes 24 false false R25.htm 2166116 - Disclosure - Income Tax Expense Sheet http://www.avangrid.com/role/IncomeTaxExpense Income Tax Expense Notes 25 false false R26.htm 2168117 - Disclosure - Stock-Based Compensation Expense Sheet http://www.avangrid.com/role/StockBasedCompensationExpense Stock-Based Compensation Expense Notes 26 false false R27.htm 2170118 - Disclosure - Variable Interest Entities Sheet http://www.avangrid.com/role/VariableInterestEntities Variable Interest Entities Notes 27 false false R28.htm 2172119 - Disclosure - Equity Method Investments Sheet http://www.avangrid.com/role/EquityMethodInvestments Equity Method Investments Notes 28 false false R29.htm 2174120 - Disclosure - Restructuring and Severance Related Expenses Sheet http://www.avangrid.com/role/RestructuringandSeveranceRelatedExpenses Restructuring and Severance Related Expenses Notes 29 false false R30.htm 2177121 - Disclosure - Subsequent Event Sheet http://www.avangrid.com/role/SubsequentEvent Subsequent Event Notes 30 false false R31.htm 2205201 - Disclosure - Significant Accounting Policies and New Accounting Pronouncements (Policies) Sheet http://www.avangrid.com/role/SignificantAccountingPoliciesandNewAccountingPronouncementsPolicies Significant Accounting Policies and New Accounting Pronouncements (Policies) Policies http://www.avangrid.com/role/SignificantAccountingPoliciesandNewAccountingPronouncements 31 false false R32.htm 2308301 - Disclosure - Revenue (Tables) Sheet http://www.avangrid.com/role/RevenueTables Revenue (Tables) Tables http://www.avangrid.com/role/Revenue 32 false false R33.htm 2314302 - Disclosure - Regulatory Assets and Liabilities (Tables) Sheet http://www.avangrid.com/role/RegulatoryAssetsandLiabilitiesTables Regulatory Assets and Liabilities (Tables) Tables http://www.avangrid.com/role/RegulatoryAssetsandLiabilities 33 false false R34.htm 2320303 - Disclosure - Fair Value of Financial Instruments and Fair Value Measurements (Tables) Sheet http://www.avangrid.com/role/FairValueofFinancialInstrumentsandFairValueMeasurementsTables Fair Value of Financial Instruments and Fair Value Measurements (Tables) Tables http://www.avangrid.com/role/FairValueofFinancialInstrumentsandFairValueMeasurements 34 false false R35.htm 2327304 - Disclosure - Derivative Instruments and Hedging (Tables) Sheet http://www.avangrid.com/role/DerivativeInstrumentsandHedgingTables Derivative Instruments and Hedging (Tables) Tables http://www.avangrid.com/role/DerivativeInstrumentsandHedging 35 false false R36.htm 2340305 - Disclosure - Post-retirement and Similar Obligations (Tables) Sheet http://www.avangrid.com/role/PostretirementandSimilarObligationsTables Post-retirement and Similar Obligations (Tables) Tables http://www.avangrid.com/role/PostretirementandSimilarObligations 36 false false R37.htm 2344306 - Disclosure - Equity (Tables) Sheet http://www.avangrid.com/role/EquityTables Equity (Tables) Tables http://www.avangrid.com/role/Equity 37 false false R38.htm 2348307 - Disclosure - Earnings Per Share (Tables) Sheet http://www.avangrid.com/role/EarningsPerShareTables Earnings Per Share (Tables) Tables http://www.avangrid.com/role/EarningsPerShare 38 false false R39.htm 2351308 - Disclosure - Segment Information (Tables) Sheet http://www.avangrid.com/role/SegmentInformationTables Segment Information (Tables) Tables http://www.avangrid.com/role/SegmentInformation 39 false false R40.htm 2356309 - Disclosure - Related Party Transactions (Tables) Sheet http://www.avangrid.com/role/RelatedPartyTransactionsTables Related Party Transactions (Tables) Tables http://www.avangrid.com/role/RelatedPartyTransactions 40 false false R41.htm 2361310 - Disclosure - Other Financial Statement Items (Tables) Sheet http://www.avangrid.com/role/OtherFinancialStatementItemsTables Other Financial Statement Items (Tables) Tables http://www.avangrid.com/role/OtherFinancialStatementItems 41 false false R42.htm 2375311 - Disclosure - Restructuring and Severance Related Expenses (Tables) Sheet http://www.avangrid.com/role/RestructuringandSeveranceRelatedExpensesTables Restructuring and Severance Related Expenses (Tables) Tables http://www.avangrid.com/role/RestructuringandSeveranceRelatedExpenses 42 false false R43.htm 2402401 - Disclosure - Background and Nature Of Operations (Detail) Sheet http://www.avangrid.com/role/BackgroundandNatureOfOperationsDetail Background and Nature Of Operations (Detail) Details 43 false false R44.htm 2406402 - Disclosure - Significant Accounting Policies and New Accounting Pronouncements - Narrative (Details) Sheet http://www.avangrid.com/role/SignificantAccountingPoliciesandNewAccountingPronouncementsNarrativeDetails Significant Accounting Policies and New Accounting Pronouncements - Narrative (Details) Details http://www.avangrid.com/role/SignificantAccountingPoliciesandNewAccountingPronouncementsPolicies 44 false false R45.htm 2409403 - Disclosure - Revenue - Narrative (Detail) Sheet http://www.avangrid.com/role/RevenueNarrativeDetail Revenue - Narrative (Detail) Details 45 false false R46.htm 2410404 - Disclosure - Revenue - Narrative Revenue Term (Details) Sheet http://www.avangrid.com/role/RevenueNarrativeRevenueTermDetails Revenue - Narrative Revenue Term (Details) Details 46 false false R47.htm 2411405 - Disclosure - Revenue - Schedule of Revenues Disaggregated by Major Source for Reportable Segments (Detail) Sheet http://www.avangrid.com/role/RevenueScheduleofRevenuesDisaggregatedbyMajorSourceforReportableSegmentsDetail Revenue - Schedule of Revenues Disaggregated by Major Source for Reportable Segments (Detail) Details 47 false false R48.htm 2412406 - Disclosure - Revenue - Schedule of Aggregate Transaction Price Allocated to Unsatisfied Performance Obligations and Expected Time to Recognize Revenue (Detail) Sheet http://www.avangrid.com/role/RevenueScheduleofAggregateTransactionPriceAllocatedtoUnsatisfiedPerformanceObligationsandExpectedTimetoRecognizeRevenueDetail Revenue - Schedule of Aggregate Transaction Price Allocated to Unsatisfied Performance Obligations and Expected Time to Recognize Revenue (Detail) Details 48 false false R49.htm 2415407 - Disclosure - Regulatory Assets and Liabilities - Additional Information (Detail) Sheet http://www.avangrid.com/role/RegulatoryAssetsandLiabilitiesAdditionalInformationDetail Regulatory Assets and Liabilities - Additional Information (Detail) Details 49 false false R50.htm 2416408 - Disclosure - Regulatory Assets and Liabilities - Rate Increases and Delivery Rate Percentages (Details) Sheet http://www.avangrid.com/role/RegulatoryAssetsandLiabilitiesRateIncreasesandDeliveryRatePercentagesDetails Regulatory Assets and Liabilities - Rate Increases and Delivery Rate Percentages (Details) Details 50 false false R51.htm 2417409 - Disclosure - Regulatory Assets and Liabilities - Current and Non-Current Assets (Detail) Sheet http://www.avangrid.com/role/RegulatoryAssetsandLiabilitiesCurrentandNonCurrentAssetsDetail Regulatory Assets and Liabilities - Current and Non-Current Assets (Detail) Details 51 false false R52.htm 2418410 - Disclosure - Regulatory Assets and Liabilities - Current and Non-Current Liabilities (Detail) Sheet http://www.avangrid.com/role/RegulatoryAssetsandLiabilitiesCurrentandNonCurrentLiabilitiesDetail Regulatory Assets and Liabilities - Current and Non-Current Liabilities (Detail) Details 52 false false R53.htm 2421411 - Disclosure - Fair Value of Financial Instruments and Fair Value Measurements - Additional Information (Detail) Sheet http://www.avangrid.com/role/FairValueofFinancialInstrumentsandFairValueMeasurementsAdditionalInformationDetail Fair Value of Financial Instruments and Fair Value Measurements - Additional Information (Detail) Details 53 false false R54.htm 2422412 - Disclosure - Fair Value of Financial Instruments and Fair Value Measurements - Fair Value of Assets and Liabilities (Detail) Sheet http://www.avangrid.com/role/FairValueofFinancialInstrumentsandFairValueMeasurementsFairValueofAssetsandLiabilitiesDetail Fair Value of Financial Instruments and Fair Value Measurements - Fair Value of Assets and Liabilities (Detail) Details 54 false false R55.htm 2423413 - Disclosure - Fair Value of Financial Instruments and Fair Value Measurements - Reconciliation of Changes in Fair Value of Financial Instruments (Detail) Sheet http://www.avangrid.com/role/FairValueofFinancialInstrumentsandFairValueMeasurementsReconciliationofChangesinFairValueofFinancialInstrumentsDetail Fair Value of Financial Instruments and Fair Value Measurements - Reconciliation of Changes in Fair Value of Financial Instruments (Detail) Details 55 false false R56.htm 2424414 - Disclosure - Fair Value of Financial Instruments and Fair Value Measurements - Valuation of Instruments (Detail) Sheet http://www.avangrid.com/role/FairValueofFinancialInstrumentsandFairValueMeasurementsValuationofInstrumentsDetail Fair Value of Financial Instruments and Fair Value Measurements - Valuation of Instruments (Detail) Details 56 false false R57.htm 2425415 - Disclosure - Fair Value of Financial Instruments and Fair Value Measurements - Schedule of Fair Value Measurement (Detail) Sheet http://www.avangrid.com/role/FairValueofFinancialInstrumentsandFairValueMeasurementsScheduleofFairValueMeasurementDetail Fair Value of Financial Instruments and Fair Value Measurements - Schedule of Fair Value Measurement (Detail) Details 57 false false R58.htm 2428416 - Disclosure - Derivative Instruments and Hedging - Offsetting of Derivatives, Locations in Condensed Consolidated Balance Sheet and Amounts of Derivatives (Detail) Sheet http://www.avangrid.com/role/DerivativeInstrumentsandHedgingOffsettingofDerivativesLocationsinCondensedConsolidatedBalanceSheetandAmountsofDerivativesDetail Derivative Instruments and Hedging - Offsetting of Derivatives, Locations in Condensed Consolidated Balance Sheet and Amounts of Derivatives (Detail) Details 58 false false R59.htm 2429417 - Disclosure - Derivative Instruments and Hedging - Net Notional Volume (Detail) Sheet http://www.avangrid.com/role/DerivativeInstrumentsandHedgingNetNotionalVolumeDetail Derivative Instruments and Hedging - Net Notional Volume (Detail) Details 59 false false R60.htm 2430418 - Disclosure - Derivative Instruments and Hedging - Summary of Hedge Contracts Recognized in Regulatory Assets and Liabilities (Detail) Sheet http://www.avangrid.com/role/DerivativeInstrumentsandHedgingSummaryofHedgeContractsRecognizedinRegulatoryAssetsandLiabilitiesDetail Derivative Instruments and Hedging - Summary of Hedge Contracts Recognized in Regulatory Assets and Liabilities (Detail) Details 60 false false R61.htm 2431419 - Disclosure - Derivative Instruments and Hedging - Additional Information (Detail) Sheet http://www.avangrid.com/role/DerivativeInstrumentsandHedgingAdditionalInformationDetail Derivative Instruments and Hedging - Additional Information (Detail) Details 61 false false R62.htm 2432420 - Disclosure - Derivative Instruments and Hedging - Effect of Derivatives in Cash Flow Hedging (Detail) Sheet http://www.avangrid.com/role/DerivativeInstrumentsandHedgingEffectofDerivativesinCashFlowHedgingDetail Derivative Instruments and Hedging - Effect of Derivatives in Cash Flow Hedging (Detail) Details 62 false false R63.htm 2433421 - Disclosure - Derivative Instruments and Hedging - Fair Value of Derivative Contract (Detail) Sheet http://www.avangrid.com/role/DerivativeInstrumentsandHedgingFairValueofDerivativeContractDetail Derivative Instruments and Hedging - Fair Value of Derivative Contract (Detail) Details 63 false false R64.htm 2434422 - Disclosure - Derivative Instruments and Hedging - Effect of Trading and Non-trading Derivatives (Detail) Sheet http://www.avangrid.com/role/DerivativeInstrumentsandHedgingEffectofTradingandNontradingDerivativesDetail Derivative Instruments and Hedging - Effect of Trading and Non-trading Derivatives (Detail) Details 64 false false R65.htm 2436423 - Disclosure - Contingencies (Detail) Sheet http://www.avangrid.com/role/ContingenciesDetail Contingencies (Detail) Details http://www.avangrid.com/role/Contingencies 65 false false R66.htm 2438424 - Disclosure - Environmental Liabilities (Detail) Sheet http://www.avangrid.com/role/EnvironmentalLiabilitiesDetail Environmental Liabilities (Detail) Details http://www.avangrid.com/role/EnvironmentalLiabilities 66 false false R67.htm 2441425 - Disclosure - Post-Retirement and Similar Obligations - Additional Information (Detail) Sheet http://www.avangrid.com/role/PostRetirementandSimilarObligationsAdditionalInformationDetail Post-Retirement and Similar Obligations - Additional Information (Detail) Details 67 false false R68.htm 2442426 - Disclosure - Post-Retirement and Similar Obligations - Periodic Benefit Costs Net (Detail) Sheet http://www.avangrid.com/role/PostRetirementandSimilarObligationsPeriodicBenefitCostsNetDetail Post-Retirement and Similar Obligations - Periodic Benefit Costs Net (Detail) Details 68 false false R69.htm 2445427 - Disclosure - Equity - Additional Information (Detail) Sheet http://www.avangrid.com/role/EquityAdditionalInformationDetail Equity - Additional Information (Detail) Details 69 false false R70.htm 2446428 - Disclosure - Equity - Accumulated Other Comprehensive Gain (Loss) (Detail) Sheet http://www.avangrid.com/role/EquityAccumulatedOtherComprehensiveGainLossDetail Equity - Accumulated Other Comprehensive Gain (Loss) (Detail) Details 70 false false R71.htm 2449429 - Disclosure - Earnings Per Share (Detail) Sheet http://www.avangrid.com/role/EarningsPerShareDetail Earnings Per Share (Detail) Details http://www.avangrid.com/role/EarningsPerShareTables 71 false false R72.htm 2452430 - Disclosure - Segment Information - Additional Information (Detail) Sheet http://www.avangrid.com/role/SegmentInformationAdditionalInformationDetail Segment Information - Additional Information (Detail) Details 72 false false R73.htm 2453431 - Disclosure - Segment Information - Adjusted Net Income (Detail) Sheet http://www.avangrid.com/role/SegmentInformationAdjustedNetIncomeDetail Segment Information - Adjusted Net Income (Detail) Details 73 false false R74.htm 2454432 - Disclosure - Segment Information - Reconciliation of Adjusted Net Income to Net Income (Detail) Sheet http://www.avangrid.com/role/SegmentInformationReconciliationofAdjustedNetIncometoNetIncomeDetail Segment Information - Reconciliation of Adjusted Net Income to Net Income (Detail) Details 74 false false R75.htm 2457433 - Disclosure - Related Party Transactions - Schedule of Related Party Transactions (Detail) Sheet http://www.avangrid.com/role/RelatedPartyTransactionsScheduleofRelatedPartyTransactionsDetail Related Party Transactions - Schedule of Related Party Transactions (Detail) Details 75 false false R76.htm 2458434 - Disclosure - Related Party Transactions - Additional Information (Details) Sheet http://www.avangrid.com/role/RelatedPartyTransactionsAdditionalInformationDetails Related Party Transactions - Additional Information (Details) Details 76 false false R77.htm 2459435 - Disclosure - Related Party Transactions - Schedule of Related Party Balances (Details) Sheet http://www.avangrid.com/role/RelatedPartyTransactionsScheduleofRelatedPartyBalancesDetails Related Party Transactions - Schedule of Related Party Balances (Details) Details 77 false false R78.htm 2462436 - Disclosure - Other Financial Statement Items - Accounts Receivable and Unbilled Revenue (Details) Sheet http://www.avangrid.com/role/OtherFinancialStatementItemsAccountsReceivableandUnbilledRevenueDetails Other Financial Statement Items - Accounts Receivable and Unbilled Revenue (Details) Details 78 false false R79.htm 2463437 - Disclosure - Other Financial Statement Items - Allowance For Credit Losses (Details) Sheet http://www.avangrid.com/role/OtherFinancialStatementItemsAllowanceForCreditLossesDetails Other Financial Statement Items - Allowance For Credit Losses (Details) Details 79 false false R80.htm 2464438 - Disclosure - Other Financial Statement Items - Additional Information (Detail) Sheet http://www.avangrid.com/role/OtherFinancialStatementItemsAdditionalInformationDetail Other Financial Statement Items - Additional Information (Detail) Details 80 false false R81.htm 2465439 - Disclosure - Other Financial Statement Items - Schedule of Accumulated Depreciation and Amortization (Details) Sheet http://www.avangrid.com/role/OtherFinancialStatementItemsScheduleofAccumulatedDepreciationandAmortizationDetails Other Financial Statement Items - Schedule of Accumulated Depreciation and Amortization (Details) Details 81 false false R82.htm 2467440 - Disclosure - Income Tax Expense (Details) Sheet http://www.avangrid.com/role/IncomeTaxExpenseDetails Income Tax Expense (Details) Details http://www.avangrid.com/role/IncomeTaxExpense 82 false false R83.htm 2469441 - Disclosure - Stock-Based Compensation Expense (Detail) Sheet http://www.avangrid.com/role/StockBasedCompensationExpenseDetail Stock-Based Compensation Expense (Detail) Details http://www.avangrid.com/role/StockBasedCompensationExpense 83 false false R84.htm 2471442 - Disclosure - Variable Interest Entities (Detail) Sheet http://www.avangrid.com/role/VariableInterestEntitiesDetail Variable Interest Entities (Detail) Details http://www.avangrid.com/role/VariableInterestEntities 84 false false R85.htm 2473443 - Disclosure - Equity Method Investments (Details) Sheet http://www.avangrid.com/role/EquityMethodInvestmentsDetails Equity Method Investments (Details) Details http://www.avangrid.com/role/EquityMethodInvestments 85 false false R86.htm 2476444 - Disclosure - Restructuring and Severance Related Expenses - Additional Information (Detail) Sheet http://www.avangrid.com/role/RestructuringandSeveranceRelatedExpensesAdditionalInformationDetail Restructuring and Severance Related Expenses - Additional Information (Detail) Details 86 false false R87.htm 2478445 - Disclosure - Subsequent Event (Details) Sheet http://www.avangrid.com/role/SubsequentEventDetails Subsequent Event (Details) Details http://www.avangrid.com/role/SubsequentEvent 87 false false All Reports Book All Reports agr-20200930.htm agr-20200930.xsd agr-20200930_cal.xml agr-20200930_def.xml agr-20200930_lab.xml agr-20200930_pre.xml agr-ex311xq32020.htm agr-ex312xq32020.htm agr-ex32xq32020.htm agr-20200930_g1.jpg http://fasb.org/srt/2020-01-31 http://xbrl.sec.gov/exch/2020-01-31 http://xbrl.sec.gov/stpr/2018-01-31 http://fasb.org/us-gaap/2020-01-31 http://xbrl.sec.gov/dei/2020-01-31 true true