| Component: (Network and Table) | |
|---|---|
| Network | 101300 - Disclosure - Post-Retirement and Similar Obligations - Estimated Future Benefit Payments (Detail) (http://www.avangrid.com/20161231/taxonomy/role/DisclosurePostRetirementAndSimilarObligationsEstimatedFutureBenefitPaymentsDetail) |
| Table | Schedule Of Defined Benefit Plans Disclosures [Table] |
| Reporting Entity [Axis] | 0001634997 (http://www.sec.gov/CIK) |
| Defined Contribution Plan Name | Improvement and Modernization Act of 2003 [Member] |
| Legal Entity | Networks and ARHI [Member] |
| Defined Benefit Plan Disclosure [Line Items] | Period [Axis] | ||
|---|---|---|---|
2016-12-31 | |||
| Defined Benefit Plans and Other Postretirement Benefit Plans | |||
| Pension Plan [Member] | Other Postretirement Benefit Plan [Member] | Defined Benefit Plan and Other Postretirement Benefit Plan | |
| Defined Contribution Plan Type | Defined Contribution Plan Type | Defined Contribution Plan Type | |
| Defined Contribution Plan Type | Defined Contribution Plan Type | Medicare Act Subsidy Receipts [Member] | |
2017 | |||
2018 | |||
2019 | |||
2020 | |||
2021 | |||
2022 - 2026 | |||