XML 86 R60.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Significant Accounting Policies (Depreciation Rates and Estimated Useful Life) (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2016 $ / Mcfe | Dec. 31, 2015 | Dec. 31, 2014 USD ($)
Merchant generation-nuclear |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Estimated Useful Lives | 44 years |  |
Cost of Service Gas and Oil Properties |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Cost of service gas and oil properties rate (per Mcfe) | $ / Mcfe | 2.08 |  |
Virginia Electric and Power Company |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Increase in depreciation |  |  | $ 38
Increase in depreciation, after tax |  |  | $ 23
Generation |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.83% | 2.78% | 2.66%
Generation | Virginia Electric and Power Company |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.83% | 2.78% | 2.66%
Transmission |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.47% | 2.42% | 2.38%
Transmission | Virginia Electric and Power Company |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.36% | 2.33% | 2.34%
Transmission | Dominion Gas Holdings, LLC |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.43% | 2.46% | 2.40%
Distribution |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 3.02% | 3.11% | 3.12%
Distribution | Virginia Electric and Power Company |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 3.32% | 3.33% | 3.34%
Storage |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.29% | 2.42% | 2.39%
Storage | Dominion Gas Holdings, LLC |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.19% | 2.44% | 2.40%
Gas gathering and processing |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.66% | 3.19% | 2.81%
Gas gathering and processing | Dominion Gas Holdings, LLC |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.58% | 3.20% | 2.82%
Distribution | Dominion Gas Holdings, LLC |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 2.55% | 2.45% | 2.47%
General and other |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 4.12% | 3.67% | 3.62%
General and other | Virginia Electric and Power Company |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 3.49% | 3.40% | 3.29%
General and other | Dominion Gas Holdings, LLC |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Average composite depreciation rates on utility property, plant and equipment (percentage) | 4.54% | 4.72% | 5.77%
Minimum | Merchant generation-other |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Estimated Useful Lives | 15 years |  |
Minimum | Gas gathering and processing |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Estimated Useful Lives | 3 years |  |
Minimum | General and other |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Estimated Useful Lives | 5 years |  |
Minimum | Dominion Gas Holdings, LLC | Gas gathering and processing |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Estimated Useful Lives | 10 years |  |
Maximum | Merchant generation-other |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Estimated Useful Lives | 36 years |  |
Maximum | Gas gathering and processing |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Estimated Useful Lives | 50 years |  |
Maximum | General and other |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Estimated Useful Lives | 59 years |  |
Maximum | Dominion Gas Holdings, LLC | Gas gathering and processing |  |  |
Public Utility, Property, Plant and Equipment [Line Items] |  |  |
Estimated Useful Lives | 50 years |  |

X
- Definition Increase in Depreciation + References No definition available. + Details
Name: | d_IncreaseinDepreciation
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Increase in Depreciation, After Tax + References No definition available. + Details
Name: | d_IncreaseinDepreciationAfterTax
Namespace Prefix: | d_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortization computed on the basis of physical units, with oil and gas converted to a common unit of measure on the basis of their approximate relative energy content. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-10.(c)(7)(i)) -URI http://asc.fasb.org/extlink&oid=50486907&loc=d3e511914-122862 + Details
Name: | us-gaap_AmortizationExpensePerPhysicalUnitOfProduction
Namespace Prefix: | us-gaap_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Composite depreciation rate for public utility plants in service. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesPropertyPlantAndEquipmentDisclosureOfCompositeDepreciationRateForPlantsInService
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_PublicUtilityPropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=d_MerchantGenerationNuclearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AmortizationExpensePerUnitOfProductionByCostCenterAxis=d_CostofServiceGasandOilPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=d_VirginiaElectricAndPowerCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=us-gaap_ElectricityGenerationPlantNonNuclearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=us-gaap_GasTransmissionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=d_DominionGasHoldingsLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=us-gaap_ElectricDistributionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=d_StorageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=us-gaap_NaturalGasProcessingPlantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=us-gaap_GasDistributionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=us-gaap_OtherPlantInServiceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=d_MerchantGenerationOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_GasGatheringAndProcessingEquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_OtherPlantInServiceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |