Dominion Energy Midstream Partners 10-Q 3 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 30, 2015shares
Document and Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Trading Symbol	DM
Entity Registrant Name	Dominion Midstream Partners, LP
Entity Central Index Key	1,603,286
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Units Outstanding
Document and Entity Information [Line Items]
Entity Units Outstanding	45,714,610
Entity Subordinated Units Outstanding
Document and Entity Information [Line Items]
Entity Units Outstanding	31,972,789

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Operating revenue	[1]	$ 103.1		$ 286.9
Operating Expenses
Purchased gas	[1]	23.4		52.8
Other operations and maintenance:
Affiliated suppliers		5.2		16.4
Other		8.6		26.7
Depreciation and amortization		9.9		30.4
Other taxes		7.3		20
Total operating expenses		54.4		146.3
Income from operations		48.7		140.6
Other income (expense)		0.2		0.6
Interest and related charges	[1]	0.1		0.3
Income from operations including noncontrolling interest before income taxes		48.8		140.9
Income tax expense		0		2.1
Net income including noncontrolling interest and DCG Predecessor		48.8		138.8
Less: Net income attributable to DCG Predecessor		0		2.3
Net income including noncontrolling interest		48.8		136.5
Less: Net income attributable to noncontrolling interest		30.8		89.1
Net income attributable to partners		18		47.4
Net income attributable to partners' ownership interest
General partner's interest in net income	[2]	0		(0.7)
Common Units
Net income attributable to partners' ownership interest
Net income attributable to limited partners		$ 10.5		$ 26.7
Net income per limited partner unit (basic and diluted)
Net income per limited partner unit (basic and diluted)		$ 0.28		$ 0.75
Subordinated Units
Net income attributable to partners' ownership interest
Net income attributable to limited partners		$ 7.5		$ 21.4
Net income per limited partner unit (basic and diluted)
Net income per limited partner unit (basic and diluted)		$ 0.24		$ 0.67
Predecessor
Operating revenue	[1]		$ 65.7		$ 245.8
Operating Expenses
Purchased gas	[1]		2.4		55.5
Other operations and maintenance:
Affiliated suppliers			2.1		6
Other			4.9		22.2
Depreciation and amortization			7.8		23.5
Other taxes			5.7		16.8
Total operating expenses			22.9		124
Income from operations			42.8		121.8
Other income (expense)			(0.1)		(0.1)
Interest and related charges	[1]		0		0
Income from operations including noncontrolling interest before income taxes			42.7		121.7
Income tax expense			16.3		46.5
Net income including noncontrolling interest and DCG Predecessor			$ 26.4		$ 75.2
[1]	See Note 17 for amounts attributable to related parties.
[2]	See Note 2 for further information.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents		$ 107	$ 175.4
Customer and other receivables		44.9	19.9
Affiliated receivables		6.2	6.1
Prepayments		13.4	9.5
Materials and supplies		12.4	8.7
Regulatory assets		2.2	1.7
Other		2.7	4.7
Total current assets		188.8	226
Investment in Equity Method Affiliate		216.4	0
Property, Plant and Equipment
Property, plant and equipment		3,416.8	2,203.1
Accumulated depreciation and amortization		(344.2)	(231.2)
Total property, plant and equipment, net		3,072.6	1,971.9
Deferred Charges and Other Assets
Goodwill	[1]	295.5	45.9
Intangible assets, net		15.9	12.1
Regulatory assets		2.7	2.5
Other		0.3	0
Total deferred charges and other assets		314.4	60.5
Total assets		3,792.2	2,258.4
Current Liabilities
Accounts payable		43.9	3.3
Payables to affiliates		4.5	2.5
Accrued payroll and taxes		4.8	1.5
Regulatory liabilities		6.8	3.6
Dominion credit facility borrowings		5.9	0
Deferred revenue		7.4	3.9
Natural gas imbalances	[2]	1.1	2.7
CPCN obligation		7.9	7.9
Other		16.1	6.4
Total current liabilities		98.4	31.8
Affiliated Long-Term Debt		300.8	0
Deferred Credits and Other Liabilities
Pension and other postretirement benefit liabilities	[2]	4.9	4.4
Regulatory liabilities		69.6	33.5
CPCN obligation		29	36.2
Asset retirement obligation		12.9	0.3
Other		5.6	1.4
Total deferred credits and other liabilities		122	75.8
Total liabilities		$ 521.2	$ 107.6
Commitments and Contingencies (see Note 15)
Equity and Partners' Capital
Total Dominion Midstream Partners, LP partners' capital		$ 1,493	$ 1,075.3
Noncontrolling interest		1,778	1,075.5
Total equity and partners' capital		3,271	2,150.8
Total liabilities and equity and partners' capital		3,792.2	2,258.4
Common Units
Equity and Partners' Capital
Common unitholders and Subordinated unitholder		615.2	395.4
Dominion
Equity and Partners' Capital
General Partner interest - Dominion (non-economic interest)		(12.6)	0
Dominion | Common Units
Equity and Partners' Capital
Common unitholders and Subordinated unitholder		418.8	213.7
Dominion | Subordinated Units
Equity and Partners' Capital
Common unitholders and Subordinated unitholder		$ 471.6	$ 466.2
[1]	There are no accumulated impairment losses.
[2]	See Note 17 for amounts attributable to related parties.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Sep. 30, 2015	Dec. 31, 2014
Common Units
Common unitholders and Subordinated unitholder - units issued	28,677,286	20,127,322
Common unitholders and Subordinated unitholder- units outstanding	28,677,286	20,127,322
Common Units | Dominion
Common unitholders and Subordinated unitholder - units issued	17,037,324	11,847,789
Common unitholders and Subordinated unitholder- units outstanding	17,037,324	11,847,789
Subordinated Units | Dominion
Common unitholders and Subordinated unitholder - units issued	31,972,789	31,972,789
Common unitholders and Subordinated unitholder- units outstanding	31,972,789	31,972,789

Consolidated Statement of Equit

Consolidated Statement of Equity and Partners' Capital - 9 months ended Sep. 30, 2015 - USD ($) $ in Millions	Total	DCG	DCGDominion	DCG Predecessor Equity	DCG Predecessor EquityDCG	DCG Predecessor EquityDCGDominion	Common Unitholders and Subordinated UnitholderCommon UnitsCommon Unitholders Public	Common Unitholders and Subordinated UnitholderCommon UnitsCommon Unitholder and Subordinated Unitholder- Dominion	Common Unitholders and Subordinated UnitholderCommon UnitsCommon Unitholder and Subordinated Unitholder- DominionDCG	Common Unitholders and Subordinated UnitholderSubordinated UnitsCommon Unitholder and Subordinated Unitholder- Dominion	General Partner Dominion (non-economic interest)General Partner Dominion (non-economic interest)	General Partner Dominion (non-economic interest)General Partner Dominion (non-economic interest)DCG	Total Dominion Midstream Partners, LP Partners' Equity and Capital	Total Dominion Midstream Partners, LP Partners' Equity and CapitalDCG	Total Dominion Midstream Partners, LP Partners' Equity and CapitalDCGDominion	Noncontrolling interest
Balance (Predecessor) at Dec. 31, 2014				$ 0
Balance at Dec. 31, 2014	$ 2,150.8						$ 395.4	$ 213.7		$ 466.2	$ 0		$ 1,075.3			$ 1,075.5
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income including noncontrolling interest	136.5						15.3	11.4		21.4	(0.7)		47.4			89.1
DCG Acquisition:
Record Dominion's net investment in DCG | Predecessor					$ (501.6)	$ 497
Record Dominion's net investment in DCG	216	$ 0	$ 497				216					$ 501.6	216	$ 0	$ 497
Net income attributable to DCG Predecessor | Predecessor						2.3
Net income attributable to DCG Predecessor	(2.3)		2.3												2.3
Contribution from Dominion to DCG prior to DCG Acquisition | Predecessor						2.3
Contribution from Dominion to DCG prior to DCG Acquisition	614		2.3								0.7		0.7		2.3	613.3
Allocation of DCG Predecessor investment | Predecessor					$ (501.6)	497
Allocation of DCG Predecessor investment	216	0	497				216					501.6	216	0	497
Settlement of net current and deferred income tax assets		(13.4)										(13.4)		(13.4)
Consideration provided to Dominion for DCG Acquisition		$ (300.8)							$ 200			$ (500.8)		$ (300.8)
Equity contributions | Predecessor						$ 2.3
Equity contributions	614		$ 2.3								0.7		0.7		$ 2.3	613.3
Purchase of common units by Dominion	0						(1.5)	1.5
Distributions	(33.9)						(10.1)	(7.8)		(16)			(33.9)
Unit awards (net of unearned compensation)	0.1						0.1						0.1
Other	0.1															0.1
Balance (Predecessor) at Sep. 30, 2015				$ 0
Balance at Sep. 30, 2015	$ 3,271						$ 615.2	$ 418.8		$ 471.6	$ (12.6)		$ 1,493			$ 1,778

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating Activities
Net income including noncontrolling interest and DCG Predecessor	$ 138.8
Adjustments to reconcile net income including noncontrolling interest and DCG Predecessor to net cash provided by operating activities:
Depreciation and amortization	30.4
Deferred income taxes	1.5
Other adjustments to income, net	1.5
Changes in:
Customer and other receivables	(18.3)
Affiliated receivables	(0.1)
Prepayments	(3.8)
Accounts payable	34.5
Payables to affiliates	1.8
Accrued payroll and taxes	2.5
Other operating assets and liabilities	6.8
Net cash provided by operating activities	195.6
Investing Activities
Plant construction and other property additions	(850)
Other	(0.4)
Net cash used in investing activities	(850.4)
Financing Activities
Dominion credit facility borrowings	5.9
Contributions from Dominion	614.6
Other	(0.2)
Net cash provided by financing activities	586.4
Decrease in cash and cash equivalents	(68.4)
Cash and cash equivalents at beginning of period	175.4
Cash and cash equivalents at end of period	107
Supplemental Cash Flow Information
Income taxes	0
Significant noncash investing and financing activities:
Accrued capital expenditures	14.8
DCG Acquisition through issuance of debt and equity
Significant noncash investing and financing activities:
DCGT Acquisition through issuance of debt and equity and Settlement of net current and deferred income tax assets	500.8
Acquisition of a noncontrolling partnership interest in Iroquois through issuance of equity
Significant noncash investing and financing activities:
Acquisition of a noncontrolling partnership interest in Iroquois through issuance of equity	216
Settlement of net current and deferred income tax assets
Significant noncash investing and financing activities:
DCGT Acquisition through issuance of debt and equity and Settlement of net current and deferred income tax assets	13.4
Equity contribution from Dominion to relieve payables to affiliates
Significant noncash investing and financing activities:
Equity contribution from Dominion	1.7
Equity contribution from Dominion related to income taxes
Significant noncash investing and financing activities:
Equity contribution from Dominion	0
Common Units
Financing Activities
Distributions to unitholders	(10.1)
Dominion | Common Units
Financing Activities
Distributions to unitholders	(7.8)
Dominion | Subordinated Units
Financing Activities
Distributions to unitholders	$ (16)
Predecessor
Operating Activities
Net income including noncontrolling interest and DCG Predecessor		$ 75.2
Adjustments to reconcile net income including noncontrolling interest and DCG Predecessor to net cash provided by operating activities:
Depreciation and amortization		23.5
Deferred income taxes		11.4
Other adjustments to income, net		0
Changes in:
Customer and other receivables		0.1
Affiliated receivables		(1.5)
Prepayments		(8.1)
Accounts payable		1.5
Payables to affiliates		1.7
Accrued payroll and taxes		1.3
Other operating assets and liabilities		4.4
Net cash provided by operating activities		109.5
Investing Activities
Plant construction and other property additions		(353.9)
Other		(0.4)
Net cash used in investing activities		(354.3)
Financing Activities
Dominion credit facility borrowings		0
Contributions from Dominion		233.6
Other		0
Net cash provided by financing activities		233.6
Decrease in cash and cash equivalents		(11.2)
Cash and cash equivalents at beginning of period		11.2
Cash and cash equivalents at end of period		0
Supplemental Cash Flow Information
Income taxes		38.6
Significant noncash investing and financing activities:
Accrued capital expenditures		7.6
Predecessor | DCG Acquisition through issuance of debt and equity
Significant noncash investing and financing activities:
DCGT Acquisition through issuance of debt and equity and Settlement of net current and deferred income tax assets		0
Predecessor | Acquisition of a noncontrolling partnership interest in Iroquois through issuance of equity
Significant noncash investing and financing activities:
Acquisition of a noncontrolling partnership interest in Iroquois through issuance of equity		0
Predecessor | Settlement of net current and deferred income tax assets
Significant noncash investing and financing activities:
DCGT Acquisition through issuance of debt and equity and Settlement of net current and deferred income tax assets		0
Predecessor | Equity contribution from Dominion to relieve payables to affiliates
Significant noncash investing and financing activities:
Equity contribution from Dominion		20
Predecessor | Equity contribution from Dominion related to income taxes
Significant noncash investing and financing activities:
Equity contribution from Dominion		1.1
Predecessor | Common Units
Financing Activities
Distributions to unitholders		0
Predecessor | Dominion | Common Units
Financing Activities
Distributions to unitholders		$ 0
Predecessor | Dominion | Subordinated Units
Financing Activities
Distributions to unitholders

Description of Business and Bas

Description of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation Description of Business Dominion Midstream is a Delaware limited partnership formed on March 11, 2014 by Dominion MLP Holding Company, LLC and Dominion Midstream GP, LLC, both indirect wholly-owned subsidiaries of Dominion, to grow a portfolio of natural gas terminaling, processing, storage, transportation and related assets. On October 20, 2014, Dominion Midstream completed the Offering of 20,125,000 common units (including 2,625,000 common units issued pursuant to the exercise of the underwriters' over-allotment option) representing limited partner interests. A registration statement on Form S-1, as amended through the time of its effectiveness, was filed by Dominion Midstream with the SEC and was declared effective on October 10, 2014. Dominion Midstream acquired from Dominion the Preferred Equity Interest and non-economic general partner interest in Cove Point, the owner and operator of the Cove Point LNG Facility and the Cove Point Pipeline. The Preferred Equity Interest is a perpetual, non-convertible preferred equity interest entitled to Preferred Return Distributions so long as Cove Point has sufficient cash and undistributed Net Operating Income (determined on a cumulative basis from the closing of the Offering) from which to make Preferred Return Distributions. Preferred Return Distributions are made on a quarterly basis and are not cumulative. The Preferred Equity Interest is also entitled to the Additional Return Distributions. On April 1, 2015, Dominion Midstream acquired from Dominion all issued and outstanding membership interests in DCG as described further in Note 2. DCG owns and operates nearly 1,500 miles of FERC-regulated open access, transportation-only interstate natural gas pipeline in South Carolina and southeastern Georgia. On September 29, 2015, Dominion Midstream acquired a 25.93% noncontrolling partnership interest in Iroquois as described further in Notes 2 and 7. Iroquois, a Delaware limited partnership, owns and operates a 416 -mile FERC-regulated interstate natural gas transmission pipeline that extends from the Canada-U.S. border through the states of New York and Connecticut. Basis of Presentation The contribution by Dominion to Dominion Midstream of the general partner interest in Cove Point and a portion of the Preferred Equity Interest is considered to be a reorganization of entities under common control. As a result, Dominion Midstream’s basis is equal to Dominion’s cost basis in the general partner interest in Cove Point and a portion of the Preferred Equity Interest. Dominion Midstream owns the general partner interest and controls Cove Point and therefore consolidates Cove Point. As such, Dominion Midstream’s investment in the Preferred Equity Interest and Cove Point's preferred equity interest are eliminated in consolidation. Dominion's retained common equity interest in Cove Point is reflected as noncontrolling interest. The DCG Acquisition is considered to be a reorganization of entities under common control. As a result, Dominion Midstream’s basis in DCG is equal to Dominion’s cost basis in the assets and liabilities of DCG. On April 1, 2015, DCG became a wholly-owned subsidiary of Dominion Midstream and is therefore consolidated by Dominion Midstream. The accompanying financial statements and related notes have been retrospectively adjusted to include the historical results and financial position of DCG beginning January 31, 2015, the inception date of common control. For the period prior to the closing of the Offering on October 20, 2014, the financial statements included in this Quarterly Report on Form 10-Q were derived from the financial statements and accounting records of Cove Point, as our predecessor for accounting purposes. The financial statements were prepared using Dominion's historical basis in the assets and liabilities of Cove Point and include all revenues, costs, assets and liabilities attributed to Cove Point. For the period subsequent to the closing of the Offering, the Consolidated Financial Statements represent the consolidated results of operations, financial position and cash flows of Dominion Midstream. The financial statements for all periods presented include costs for certain general, administrative and corporate expenses assigned by DRS or Dominion Payroll to Dominion Midstream and Cove Point on the basis of direct and allocated methods in accordance with Dominion Midstream's services agreements with DRS and Dominion Payroll and Cove Point's services agreement with DRS. Where costs incurred cannot be determined by specific identification, the costs are allocated based on the proportional level of effort devoted by DRS or Dominion Payroll resources that is attributable to the entities, determined by reference to number of employees, salaries and wages and other similar measures for the relevant DRS or Dominion Payroll department. Management believes the assumptions and methodologies underlying the allocation of general corporate overhead expenses are reasonable. Nevertheless, the Consolidated Financial Statements prior to the Offering may not include all of the actual expenses that would have been incurred had we been a stand-alone publicly traded partnership during the periods presented, and may not reflect our actual results of operations, financial position and cash flows had we been a stand-alone publicly traded partnership during the periods prior to the Offering.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Acquisition	Acquisitions DCG On April 1, 2015, Dominion Midstream entered into a Purchase, Sale and Contribution Agreement with Dominion pursuant to which Dominion Midstream purchased from Dominion all of the issued and outstanding membership interests of DCG in exchange for total consideration of approximately $500.8 million , as adjusted for working capital. Total consideration to Dominion consisted of the issuance of a two -year $300.8 million senior unsecured promissory note, as adjusted for working capital, payable to Dominion at an annual interest rate of 0.6% , and 5,112,139 common units, valued at $200.0 million , representing limited partner interests in Dominion Midstream, to Dominion. The number of units was based on the volume weighted average trading price of Dominion Midstream's common units for the 10 trading days prior to April 1, 2015, or $39.12 per unit. Subsequent to the DCG Acquisition, total transaction and transition costs of $1.5 million were expensed as incurred to operations and maintenance expense in the Consolidated Statements of Income, including $0.5 million for the three months ended September 30, 2015. These costs were paid by Dominion. Dominion did not seek reimbursement for $0.7 million of such costs incurred subsequent to the DCG Acquisition, and accordingly Dominion Midstream recognized a capital contribution by the general partner. The DCG Acquisition supports the expansion of Dominion Midstream's portfolio of natural gas terminaling, processing, storage, transportation and related assets. The contribution of DCG by Dominion to Dominion Midstream is considered to be a reorganization of entities under common control. Accordingly, Dominion Midstream's net investment in DCG is recorded at Dominion's historical cost of $501.6 million as of April 1, 2015. Common control began on January 31, 2015, concurrent with Dominion's acquisition of DCG from SCANA, which was accounted for using the acquisition method of accounting. Accordingly, the Consolidated Financial Statements of Dominion Midstream reflect DCG's financial results beginning January 31, 2015. In connection with the DCG Acquisition, Dominion Midstream entered into a registration rights agreement with Dominion pursuant to which Dominion Midstream must register the 5,112,139 common units issued to Dominion at its request, subject to certain terms and conditions. Additionally, at the time of Dominion's acquisition of DCG, DCG entered into services agreements and an intercompany tax sharing agreement with Dominion as described in Note 17. Iroquois On August 14, 2015, Dominion Midstream entered into Contribution Agreements with NG and NJNR. On September 29, 2015, pursuant to the Contribution Agreements, Dominion Midstream acquired a 25.93% noncontrolling partnership interest in Iroquois, consisting of NG’s 20.4% and NJNR’s 5.53% partnership interests in Iroquois and, in exchange, Dominion Midstream issued common units representing limited partnership interests in Dominion Midstream to both NG ( 6,783,373 common units) and NJNR ( 1,838,932 common units). The number of units was based on the volume-weighted average trading price of Dominion Midstream’s common units for the five trading days prior to August 14, 2015, or $33.23 per unit. The acquisition of the 25.93% noncontrolling partnership interest in Iroquois supports the expansion of Dominion Midstream’s portfolio of natural gas terminaling, processing, storage, transportation and related assets. The Iroquois investment, accounted for under the equity method, was recorded at $216.4 million based on the value of Dominion Midstream's common units at closing, including $0.4 million of external transaction costs. NG and NJNR agreed to certain transfer restrictions applicable to the 8,622,305 common units issued to them, including, with limited exceptions, a one -year lockup period following the closing of the transactions described above. In addition, at closing, Dominion Midstream entered into registration rights agreements with NG and NJNR pursuant to which Dominion Midstream is required to register the common units issued to NG and NJNR for resale when Dominion Midstream became eligible to file a registration statement on Form S-3. Such registration statement, filed on November 2, 2015, does not change the lockup periods to which NG and NJNR are subject. No market issuance of the common units is planned in connection with the transactions described above.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Interim Financial Information and Estimates As permitted by the rules and regulations of the SEC, Dominion Midstream's accompanying unaudited Consolidated Financial Statements exclude certain footnote disclosures normally included in annual audited consolidated financial statements prepared in accordance with GAAP. These unaudited Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes in Dominion Midstream’s Annual Report on Form 10-K for the year ended December 31, 2014. In the opinion of management, the accompanying unaudited Consolidated Financial Statements contain all adjustments necessary to present fairly Dominion Midstream's financial position as of September 30, 2015, its results of operations for the three and nine months ended September 30, 2015 and 2014, its cash flows for the nine months ended September 30, 2015 and 2014, and its changes in equity for the nine months ended September 30, 2015. Such adjustments are normal and recurring in nature unless otherwise noted. Dominion Midstream makes certain estimates and assumptions in preparing its Consolidated Financial Statements in accordance with GAAP. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses for the periods presented. Actual results may differ from those estimates. The results of operations for interim periods are not necessarily indicative of the results expected for the full year. Information for quarterly periods is affected by seasonal variations in sales, rate changes, purchased gas expenses and other factors. Asset Retirement Obligations Dominion Midstream recognizes AROs at fair value as incurred or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement activities to be performed. These amounts are generally capitalized as costs of the related tangible long-lived assets. Since relevant market information is not available, fair value is estimated using discounted cash flow analyses. At least annually, Dominion Midstream evaluates the key assumptions underlying its AROs including estimates of the amounts and timing of future cash flows associated with retirement activities. AROs are adjusted when significant changes in these assumptions are identified. Dominion Midstream reports accretion of AROs and depreciation on asset retirement costs associated with its natural gas pipeline assets as an adjustment to the related regulatory liabilities when revenue is recoverable from customers for AROs. Investment in Equity Method Affiliate Investments in affiliates where Dominion Midstream exercises significant influence over the operating activities of the entity, but does not control the entity, are accounted for using the equity method. Such investments are included in investment in equity method affiliate in the Consolidated Balance Sheets. Dominion Midstream records equity method adjustments in earnings from equity method affiliate in the Consolidated Statements of Income, including its proportionate share of investee income or loss and other adjustments required by the equity method. Dominion Midstream periodically evaluates its equity method investment to determine whether a decline in fair value should be considered other-than-temporary. If a decline in fair value of the investment is determined to be other-than-temporary, the investment is written down to its fair value at the end of the reporting period.

Net Income Per Limited Partner

Net Income Per Limited Partner Unit	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Net Income Per Limited Partner Unit	Net Income Per Limited Partner Unit Net income per limited partner unit applicable to common and subordinated units is computed by dividing the respective limited partners’ interest in net income attributable to Dominion Midstream, after deducting any incentive distributions, by the weighted average number of common units and subordinated units outstanding. Because Dominion Midstream has more than one class of participating securities, the two-class method is used when calculating the net income per unit applicable to limited partners. The classes of participating securities include common units, subordinated units and IDRs. Dominion Midstream’s net income is allocated to the limited partners in accordance with their respective partnership interests, after giving effect to priority income allocations for incentive distributions, if any, to Dominion, the holder of the IDRs, pursuant to the partnership agreement. The distributions are declared and paid following the close of each quarter. Earnings in excess of distributions are allocated to the limited partners based on their respective ownership interests. Payments made to Dominion Midstream's unitholders are determined in relation to actual distributions declared and are not based on the net income allocations used in the calculation of earnings per limited partner unit. Net income per limited partner unit is only calculated for the periods subsequent to the Offering as no units were outstanding prior to October 20, 2014. Diluted net income per limited partner unit is the same as basic net income per limited partner unit as there were no potentially dilutive common or subordinated units outstanding as of September 30, 2015. The calculation of earnings per limited partner unit is as follows: Three Months Ended September 30, 2015 Nine Months Ended September 30, 2015 (millions) Net income attributable to partners $ 18.0 $ 47.4 Less: General partner allocation (1) — (0.7 ) Distributions declared on: Incentive distribution holder rights (2) — — Common units (3) 9.1 22.5 Subordinated units (3) 6.4 18.0 Total distributions declared 15.5 40.5 Undistributed earnings $ 2.5 $ 7.6 (1) See Note 2 for further information. (2) Dominion is a non-economic general partner that holds all of the IDRs. (3) On October 23, 2015, the Board of Directors of our general partner declared a quarterly cash distribution of $0.2000 per unit, totaling $15.5 million for the three months ended September 30, 2015. This distribution will be paid on November 13, 2015 to unitholders of record on November 3, 2015. The amount of distributions declared for the three months ended September 30, 2015 is based on the units outstanding at that date. On July 17, 2015, the Board of Directors of our general partner declared a quarterly cash distribution of $0.1875 per unit, totaling $12.9 million , for the three months ended June 30, 2015. This distribution was paid on August 14, 2015 to unitholders of record on August 4, 2015. On April 22, 2015, the Board of Directors of our general partner declared a quarterly cash distribution of $0.1750 per unit, totaling $12.1 million , for the three months ended March 31, 2015. This distribution was paid on May 15, 2015 to unitholders of record on May 5, 2015. Basic and diluted net income per limited partner unit Common Units Subordinated Units General Partner Total (millions, except for weighted average units and per unit data) Three Months Ended September 30, 2015 Distributions declared $ 9.1 $ 6.4 $ — $ 15.5 Undistributed earnings 1.3 1.2 — 2.5 Net income attributable to partners $ 10.4 $ 7.6 $ — $ 18.0 Weighted average units outstanding 37,279,747 31,972,789 Net income per limited partner unit $ 0.28 $ 0.24 Nine Months Ended September 30, 2015 General partner allocation $ — $ — $ (0.7 ) $ (0.7 ) Distributions declared 22.5 18.0 — 40.5 Undistributed earnings 4.0 3.6 — 7.6 Net income attributable to partners $ 26.5 $ 21.6 $ (0.7 ) $ 47.4 Weighted average units outstanding 35,470,133 31,972,789 Net income per limited partner unit $ 0.75 $ 0.67

Unit Activity

Unit Activity	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Unit Activity	Unit Activity Activity in the number of units was as follows: Common Public Dominion Subordinated General Partner Total (non-economic interest) Balance at December 31, 2014 20,127,322 11,847,789 31,972,789 — 63,947,900 Unit-based compensation 5,055 — — — 5,055 Units issued in connection with the DCG Acquisition — 5,112,139 — — 5,112,139 Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois 8,622,305 — — — 8,622,305 Dominion purchase of common units (1) (77,396 ) 77,396 — — — Balance at September 30, 2015 28,677,286 17,037,324 31,972,789 — 77,687,399 (1) These shares were purchased by Dominion as part of Dominion's program initiated in September 2015 to purchase from the market up to $50.0 million common units representing limited partner interests in Dominion Midstream by September 2016 at the discretion of Dominion's management. In October 2015, Dominion purchased approximately 478,000 additional common units.

Operating Revenue

Operating Revenue	9 Months Ended
	Sep. 30, 2015
Revenue Recognition [Abstract]
Operating Revenue	Operating Revenue Dominion Midstream's operating revenue consists of the following: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (millions) Gas transportation and storage $ 78.1 $ 62.5 $ 231.7 $ 193.0 Other 25.0 3.2 55.2 52.8 Total operating revenue $ 103.1 $ 65.7 $ 286.9 $ 245.8

Equity Method Investments

Equity Method Investments	9 Months Ended
	Sep. 30, 2015
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments	Equity Method Investments At September 30, 2015, Dominion Midstream used the equity method to account for its 25.93% noncontrolling partnership interest in Iroquois. At September 30, 2015, the carrying amount of Dominion Midstream’s investment of $216.4 million exceeded its share of underlying equity in net assets by approximately $121.7 million . The difference reflects equity method goodwill and is not being amortized. See further discussion of Iroquois in Notes 1 and 13.

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment Major classes of property, plant and equipment and their respective balances for Dominion Midstream are as follows: September 30, 2015 December 31, 2014 (millions) Storage $ 875.0 $ 882.0 Transmission 669.1 323.9 Plant under construction 1,834.8 972.3 General and other 37.9 24.9 Total property, plant and equipment $ 3,416.8 $ 2,203.1 The increase in property, plant and equipment is primarily related to the DCG Acquisition and capital expenditures for the Liquefaction Project. During the nine months ended September 30, 2015 and 2014, Dominion Midstream capitalized interest costs and AFUDC of $1.4 million and $0.1 million , respectively, to property, plant and equipment. Depreciation rates on utility property, plant and equipment are as follows: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (percent) Storage 2.38 2.38 2.38 2.39 Transmission 2.31 2.82 2.29 2.82 General and other 7.65 4.19 7.65 3.92

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill The changes in Dominion Midstream's carrying amount and segment allocation of goodwill are presented below: Dominion Energy Corporate and Other Total (millions) Nine Months Ended September 30, 2015 Beginning balance (1) $ 45.9 $ — $ 45.9 DCG Acquisition 249.6 — 249.6 Ending balance (1) $ 295.5 $ — $ 295.5 (1) There are no accumulated impairment losses. Other Intangible Assets Dominion Midstream's other intangible assets are subject to amortization over their estimated useful lives. Amortization expense for intangible assets was $0.6 million and $1.5 million for the three and nine months ended September 30, 2015, respectively. Amortization expense was $0.1 million and $0.4 million for the three and nine months ended September 30, 2014, respectively. The increase in intangible assets is primarily due to software acquired in the DCG Acquisition. The acquired intangible assets have an estimated weighted-average amortization period of approximately five years. The components of intangible assets are as follows: September 30, 2015 December 31, 2014 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization (millions) Software and other $ 31.0 $ 22.8 $ 6.5 $ 2.4 Licenses 11.0 3.3 11.0 3.0 Total $ 42.0 $ 26.1 $ 17.5 $ 5.4

Regulatory Assets and Liabiliti

Regulatory Assets and Liabilities	9 Months Ended
	Sep. 30, 2015
Regulated Operations [Abstract]
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities Regulatory assets and liabilities include the following: September 30, 2015 December 31, 2014 (millions) Regulatory assets: Unrecovered gas costs (1) $ 1.9 $ 1.5 Other 0.3 0.2 Regulatory assets-current 2.2 1.7 Income taxes recoverable through future rates (2) 2.7 2.5 Regulatory assets-non-current 2.7 2.5 Total regulatory assets $ 4.9 $ 4.2 Regulatory liabilities: Overrecovered gas costs (1) $ 0.2 $ 0.5 LNG cargo obligations (3) 3.3 3.0 Customer bankruptcy settlement (4) 3.0 — Other 0.3 0.1 Regulatory liabilities-current 6.8 3.6 Provision for future cost of removal (5) 47.9 33.0 Customer bankruptcy settlement (4) 21.1 — Other 0.6 0.5 Regulatory liabilities-non-current 69.6 33.5 Total regulatory liabilities $ 76.4 $ 37.1 (1) Reflects unrecovered/overrecovered gas costs, which are subject to annual filings with FERC. (2) Amounts to be recovered through future rates to pay income taxes that become payable by unitholders when rate revenue is provided to recover AFUDC-equity when such amounts are recovered through book depreciation. (3) Reflects obligations to the Import Shippers for LNG cargo received. See Note 9 to the Consolidated Financial Statements in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014 for further information. (4) Represents the balance of proceeds from the monetization of a bankruptcy claim acquired as part of the DCG Acquisition, which is being amortized into operating revenue through February 2024. (5) Rates charged to customers include a provision for the cost of future activities to remove assets that are expected to be incurred at the time of retirement. At September 30, 2015, approximately $2.2 million of regulatory assets represented past expenditures on which Dominion Midstream does not currently earn a return. These expenditures are expected to be recovered within one year.

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2015
Regulated Operations [Abstract]
Regulatory Matters	Regulatory Matters FERC regulates the transportation and sale for resale of natural gas in interstate commerce under the NGA and the Natural Gas Policy Act of 1978, as amended. Under the NGA, FERC has authority over rates, terms and conditions of services performed by Cove Point and DCG. FERC also has jurisdiction over siting, construction and operation of natural gas import facilities and interstate natural gas pipeline facilities. There have been no significant developments regarding the regulatory matters disclosed in Note 9 to the Consolidated Financial Statements in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014. During the second quarter of 2013, DCG executed binding precedent agreements for the approximately $35 million Edgemoor Project. FERC approved the Edgemoor Project in February 2015 and construction commenced in March 2015. The project is expected to be placed into service in the fourth quarter of 2015. In April 2014, DCG executed a binding precedent agreement for the approximately $35 million Columbia to Eastover Project. In May 2015, DCG filed an application to request FERC authorization to construct and operate the project facilities, which are expected to be in service in the second quarter of 2016. In October 2015, Cove Point received authorization to construct the approximately $30 million St. Charles Transportation Project and the approximately $40 million Keys Energy Project. The St. Charles Transportation project is anticipated to be placed into service in June 2016. The Keys Energy Project is anticipated to be placed into service in March 2017.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2015
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations AROs represent obligations that result from laws, statutes, contracts and regulations related to the eventual retirement of certain of Dominion Midstream's long-lived assets. Dominion Midstream's AROs primarily represent the cost associated with the legal obligation to cap and purge underground transmission pipe and the interim retirement of natural gas transmission pipeline components. The changes to AROs during 2014 and 2015 are as follows: Nine Months Ended Year Ended September 30, 2015 December 31, 2014 (millions) Beginning balance (1) $ 0.4 $ 0.4 DCG Acquisition 12.6 — Obligations settled during the period (0.9 ) — Revisions in estimated cash flows 1.7 — Accretion 0.4 — Ending balance (1) $ 14.2 $ 0.4 (1) Includes $0.1 million and $1.3 million reported in other current liabilities at December 31, 2014, and September 30, 2015, respectively. Under the terms of the 2005 Agreement, Cove Point would be responsible for certain onshore and offshore site restoration activities at the Cove Point site only if it voluntarily tenders title according to the terms of this agreement. As Cove Point is permitted to operate the Cove Point LNG Facility for an indefinite time period and currently has no plans to voluntarily tender title, Cove Point does not have sufficient information to determine a reasonable range of settlement dates for decommissioning and therefore has not recorded an asset retirement obligation.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities The primary beneficiary of a VIE is required to consolidate the VIE and to disclose certain information about its significant variable interests in the VIE. The primary beneficiary of a VIE is the entity that has both 1) the power to direct the activities that most significantly impact the entity’s economic performance and 2) the obligation to absorb losses or receive benefits from the entity that could potentially be significant to the VIE. Iroquois Dominion Midstream owns a 25.93% noncontrolling partnership interest in Iroquois. See Notes 1 and 7 for further detail regarding the nature of this entity. Dominion Midstream concluded that Iroquois is a VIE because a non-affiliated Iroquois equity holder has the ability during a limited period of time to transfer its ownership interests to another Iroquois equity holder or its affiliate. At September 30, 2015, Dominion Midstream concluded that it is not the primary beneficiary of Iroquois as it does not have the power to direct the activities of Iroquois that most significantly impact its economic performance, as the power to direct is shared among multiple unrelated parties. If Iroquois determines capital contributions are required, Dominion Midstream would be obligated to provide the portion of capital contributions based on its ownership percentage. Dominion Midstream’s maximum exposure to loss is limited to its current and future investment. DRS and Dominion Payroll In connection with the Offering, our general partner entered into a services agreement with DRS. DRS provides administrative, management and other services to Dominion and its subsidiaries as a subsidiary service company. From time to time and at the option of our general partner, our general partner will request that DRS provide, and reimburse DRS for the cost of providing, such administrative, management and other services as it deems necessary or appropriate for our operations. We will reimburse our general partner and its affiliates for the associated costs of obtaining these services. Additionally, in connection with Dominion’s acquisition of DCG, DCG entered into services agreements beginning February 1, 2015 with DRS, for similar services as described above, and with Dominion Payroll, which provides human resources and operations services to Dominion and its subsidiaries as a subsidiary service company. Dominion Midstream purchased shared services from DRS and Dominion Payroll of approximately $6.8 million and $20.1 million during the three and nine months ended September 30, 2015. Cove Point purchased shared services from DRS of approximately $3.1 million and $9.2 million for the three and nine months ended September 30, 2014. The Consolidated Balance Sheets at September 30, 2015 and December 31, 2014 include amounts due from Dominion Midstream to DRS and Dominion Payroll of approximately $1.8 million and $1.7 million , respectively. Dominion Midstream determined that neither it nor any of its consolidated entities is the most closely associated entity with either DRS or Dominion Payroll, affiliated variable interest entities, and therefore none is the primary beneficiary. Neither Dominion Midstream nor any of its consolidated entities has any obligation to absorb more than its allocated share of DRS or Dominion Payroll costs.

Affiliated Long-Term Debt

Affiliated Long-Term Debt	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Affiliated Long-Term Debt	Affiliated Long-Term Debt In connection with the DCG Acquisition, Dominion Midstream issued a two -year, $300.8 million senior unsecured promissory note payable to Dominion, as adjusted for working capital, at an annual fixed interest rate of 0.6% . Interest on the note is payable quarterly, and all principal and accrued interest is due and payable at maturity on April 1, 2017, which under certain conditions can be extended at the option of Dominion Midstream to October 1, 2017. Interest charges related to Dominion Midstream's borrowing from Dominion were $0.5 million and $1.0 million for the three and nine months ended September 30, 2015, respectively. At September 30, 2015, accrued interest payable to Dominion of $0.5 million was recorded in payables to affiliates on the Consolidated Balance Sheet. The debt instrument described above is reported at historical cost. At September 30, 2015, the fair value of Dominion Midstream's outstanding debt was $285.4 million . The estimated fair value has been determined using available market information and valuation methodologies considered appropriate by management. The fair value was calculated using market interest rates currently available for issuance of debt with similar terms and remaining maturities. The fair value measurement is classified as Level 2. The key terms of the note payable to Dominion include a prohibition on the incurrence of additional indebtedness (other than under the credit facility with Dominion discussed in Note 17) and a negative pledge applicable to liens on the assets of Dominion Midstream, but which does not apply to the assets of subsidiaries of Dominion Midstream. The note payable does not include any financial covenants. If Dominion Midstream fails to make payments under the note payable or becomes subject to bankruptcy or other insolvency proceedings, Dominion may accelerate Dominion Midstream’s payment obligations under the note payable.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies As a result of issues generated in the ordinary course of business, Dominion Midstream is involved in legal proceedings before various courts and is periodically subject to governmental examinations (including by FERC), inquiries and investigations. Certain legal proceedings and governmental examinations involve demands for unspecified amounts of damages, are in an initial procedural phase, involve uncertainty as to the outcome of pending appeals or motions, or involve significant factual issues that need to be resolved, such that it is not possible for Dominion Midstream to estimate a range of possible loss. For such matters that Dominion Midstream cannot estimate, a statement to this effect is made in the description of the matter. Other matters may have progressed sufficiently through the litigation or investigative processes such that Dominion Midstream is able to estimate a range of possible loss. For legal proceedings and governmental examinations for which Dominion Midstream is able to reasonably estimate a range of possible losses, an estimated range of possible loss is provided, in excess of the accrued liability (if any) for such matters. Estimated ranges of loss are inclusive of legal fees and net of any anticipated insurance recoveries. Any estimated range is based on currently available information and involves elements of judgment and significant uncertainties. Any accrued liability is recorded on a gross basis with a receivable also recorded for any probable insurance recoveries. Any estimated range of possible loss may not represent Dominion Midstream’s maximum possible loss exposure. The circumstances of such legal proceedings and governmental examinations will change from time to time and actual results may vary significantly from the current estimate. Management does not anticipate that the liabilities, if any, arising from such proceedings would have a material effect on Dominion Midstream’s financial position, liquidity or results of operations. Cove Point Natural Heritage Trust Under the terms of the 2005 Agreement, Cove Point is required to make an annual contribution to the Cove Point Natural Heritage Trust, an affiliated non-profit trust focused on the preservation and protection of ecologically sensitive sites at or near Cove Point, of $0.3 million for each year the facility is in operation. These annual payments are recorded in other operations and maintenance expense in the Consolidated Statements of Income. If Cove Point voluntarily tenders title according to the terms of this agreement, no contributions are required. There are no current plans to voluntarily tender title to the Cove Point site. Surety Bonds At September 30, 2015, Cove Point had purchased $10.9 million of surety bonds. Under the terms of surety bonds, Cove Point is obligated to indemnify the respective surety bond company for any amounts paid. Lease Commitments Dominion Midstream leases various facilities, vehicles and equipment under operating lease arrangements, the majority of which include terms of one year or less, require payments on a monthly or annual basis and can be canceled at any time. Rental expense for Dominion Midstream totaled $0.7 million and $2.1 million for the three and nine months ended September 30, 2015, respectively. The majority of rent expense is included within other operations and maintenance expense in the Consolidated Statements of Income.

Credit Risk

Credit Risk	9 Months Ended
	Sep. 30, 2015
Risks and Uncertainties [Abstract]
Credit Risk	Credit Risk Credit risk is the risk of financial loss if counterparties fail to perform their contractual obligations. In order to minimize overall credit risk, credit policies are maintained, including the evaluation of counterparty financial condition. In addition, counterparties may make available collateral, including letters of credit, payment guarantees or cash deposits. Dominion Midstream provides service to approximately seventy customers, including the Storage Customers, marketers or end users and the Import Shippers. The two largest customers comprised approximately 71% of the total transportation and storage revenues for each of the three and nine months ended September 30, 2015, with Dominion Midstream's largest customer representing approximately 56% and 57% of such amounts in each period, respectively. For each of the three and nine months ended September 30, 2014, Cove Point's three largest customers comprised approximately 94% of the total transportation and storage revenues, with Cove Point's largest customer representing approximately 73% of such amounts in each period. Dominion Midstream maintains a provision for credit losses based on factors surrounding the credit risk of its customers, historical trends and other information. At September 30, 2015, the provision for credit losses was less than $0.1 million . Management believes, based on credit policies and the September 30, 2015 provision for credit losses, that it is unlikely that a material adverse effect on financial position, results of operations or cash flows would occur as a result of counterparty nonperformance.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2015
Related Party Transactions [Abstract]
Related Party Transactions	Related-Party Transactions Dominion Midstream engages in related-party transactions primarily with other Dominion subsidiaries (affiliates). Dominion Midstream's receivable and payable balances with affiliates are settled based on contractual terms or on a monthly basis, depending on the nature of the underlying transactions. Participation in certain Dominion benefit plans is described in Note 10 to the Consolidated Financial Statements in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014. At September 30, 2015 and December 31, 2014, amounts due to Dominion associated with these benefit plans were $4.9 million and $4.4 million , respectively, recorded in pension and other postretirement benefit liabilities in the Consolidated Balance Sheets. Transactions related to the DCG Acquisition are described in Notes 2 and 14. A discussion of the remaining significant related party transactions follows. Transactions with Affiliates DRS provides accounting, legal, finance and certain administrative and technical services to Dominion Midstream and Dominion Payroll provides human resources and operations services to Dominion Midstream as a subsidiary service company. Refer to Note 13 for further information. Dominion may seek reimbursement from DCG for costs incurred related to Dominion's transition services agreement with SCANA to provide administrative functions related to DCG. Subsequent to the DCG Acquisition, DCG reimbursed Dominion a total of $2.1 million for such costs, including $1.0 million for the three months ended September 30, 2015. Dominion Midstream provides transportation services to affiliates and affiliates provide goods and services to Dominion Midstream. Affiliated transactions are presented below: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (millions) Sales of natural gas transportation services to affiliates $ 0.6 $ 0.5 $ 1.7 $ 1.9 Purchased gas from affiliates 0.1 0.1 0.4 0.5 Goods and services provided by affiliates to Dominion Midstream (1) 8.6 3.9 25.3 11.5 (1) Includes $3.4 million and $8.9 million of capitalized expenditures for the three and nine months ended September 30, 2015, respectively, and $1.8 million and $5.5 million for the three and nine months ended September 30, 2014, respectively. Advance from Affiliate An outstanding advance of $20.0 million previously received by Cove Point from an affiliate was converted to an equity contribution in March 2014. Dominion Credit Facility In connection with the Offering, Dominion Midstream entered into a credit facility with Dominion with a borrowing capacity of $300 million . A summary of certain key terms of the credit facility with Dominion is included in Note 14 to the Consolidated Financial Statements in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014. At September 30, 2015, $5.9 million was outstanding against the credit facility. No amounts were outstanding at December 31, 2014. Outstanding borrowings are presented within current liabilities as such amounts could become payable on demand after a 90 -day termination notice provided by either party. No such notice has been provided through the date of this filing. Interest charges related to Dominion Midstream's borrowings against the facility were less than $0.1 million for the three and nine months ended September 30, 2015. Income Taxes Prior to the Offering, Cove Point participated in Dominion's intercompany tax sharing agreement as described in Note 15 to the Consolidated Financial Statements in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014. Cove Point's participation in this tax sharing agreement was terminated in 2014 in connection with the Offering. At the time of the Offering, Cove Point settled net income taxes payable and deferred income taxes to Dominion of $147.9 million through equity contributions from Dominion. Prior to the Offering, Cove Point settled net income taxes payable to Dominion of $1.2 million through equity contributions from Dominion during the year ended December 31, 2014. DCG participated in Dominion's intercompany tax sharing agreement from February 1, 2015 through March 31, 2015. DCG's participation in this tax sharing agreement was subsequently terminated in connection with the DCG Acquisition. At the time of the DCG Acquisition, DCG settled income taxes payable and net deferred income taxes of $13.4 million through an equity transaction with Dominion. Natural Gas Imbalances Dominion Midstream maintains natural gas imbalances with affiliates. The imbalances with affiliates are provided below: September 30, 2015 December 31, 2014 (millions) Imbalances payable to affiliates $ 0.9 $ 2.5 Right of First Offer In connection with the Offering, Dominion Midstream entered into a right of first offer agreement with Dominion as described in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014. There have been no changes to this agreement. Contributions from Dominion For the nine months ended September 30, 2015, Dominion contributed $613.3 million to Cove Point to fund capital expenditures related to the Liquefaction Project, including $341.5 million during the third quarter. In October 2015, Dominion contributed $113.2 million to Cove Point to fund capital expenditures related to the Liquefaction Project. In February 2015, Dominion contributed $1.3 million in cash to DCG to fund operations. Transaction and transition costs incurred by the DCG Predecessor were attributed to Dominion Midstream and expensed in operations and maintenance expense in the Consolidated Statements of Income. At the time of the DCG Acquisition, Dominion Midstream settled amounts payable to Dominion of $1.0 million through equity contributions from Dominion. Subsequent to the DCG Acquisition, Dominion allocated transaction and transition costs of $1.5 million to Dominion Midstream, of which Dominion did not seek reimbursement for $0.7 million as described further in Note 2.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Dominion Midstream is organized as an MLP, a pass-through entity for U.S. federal and state income tax purposes. Each unitholder is responsible for taking into account the unitholder’s respective share of Dominion Midstream’s items of taxable income, gain, loss and deduction in the preparation of income tax returns. Upon the closing of the Offering, Cove Point became a pass-through entity for U.S. federal and state income tax purposes. Effective April 1, 2015, the date of the DCG Acquisition, DCG is treated as a component of Dominion Midstream for income tax purposes. Accordingly, for the three months ended September 30, 2015, Dominion Midstream's Consolidated Financial Statements do not include income taxes. Prior to the completion of the Offering, Cove Point was not treated as a partnership for U.S. federal and state income tax purposes. Its business activities were included in the consolidated U.S. federal and certain state income tax returns of Dominion or DCPI. DCG operated as a taxable corporation at the time of Dominion's acquisition of DCG. In March 2015, DCG converted to a single member limited liability company and as a result, became a disregarded entity for income tax purposes and was treated as a taxable division of its corporate parent. Its business activities from January 31, 2015 through March 31, 2015, will be included in the consolidated U.S. federal and certain state income tax returns of Dominion. Cove Point and DCG's current income taxes were based on taxable income or loss, determined on a separate company basis, and, where applicable, settled in accordance with the principles of Dominion’s intercompany tax sharing agreement. The settlement of DCG’s federal and state income taxes payable and net deferred income taxes is reflected as an equity transaction in Dominion Midstream’s Consolidated Financial Statements. For the nine months ended September 30, 2015 and 2014, the statutory U.S. federal income tax rate reconciles to the effective income tax rate as follows: Nine Months Ended September 30, 2015 2014 U.S. statutory rate 35.0 % 35.0 % Partnership income not subject to income taxes (1) (33.6 ) — Increases resulting from: State taxes, net of federal benefit (2) 0.1 3.2 Effective tax rate 1.5 % 38.2 % (1) Reflects the pass-through entity status of Dominion Midstream, including the operations of DCG subsequent to the DCG Acquisition, and Cove Point. (2) 2015 amounts are attributable to the operations of DCG prior to the DCG Acquisition, and 2014 amounts are attributable to Cove Point. See Note 15 to the Consolidated Financial Statements in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014 for additional information.

Operating Segment

Operating Segment	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Operating Segment	Operating Segment Dominion Midstream is organized primarily on the basis of products and services sold in the U.S. Dominion Energy, Dominion Midstream's operating segment, consists of natural gas transportation, storage and regasification services. Dominion Midstream also reports a Corporate and Other segment. The Corporate and Other segment primarily includes specific items attributable to Dominion Midstream's operating segment that are not included in profit measures evaluated by executive management in assessing the segment's performance. The following table presents segment information pertaining to Dominion Midstream's operations: Dominion Energy Corporate and Other Total (millions) Three Months Ended September 30, 2015 Operating revenue $ 103.1 $ — $ 103.1 Net income including noncontrolling interest and DCG Predecessor 48.8 — 48.8 Net income attributable to partners 18.0 — 18.0 Three Months Ended September 30, 2014 Operating revenue $ 65.7 $ — $ 65.7 Net income including noncontrolling interest and DCG Predecessor 26.4 — 26.4 Nine Months Ended September 30, 2015 Operating revenue $ 286.9 $ — $ 286.9 Net income including noncontrolling interest and DCG Predecessor 140.5 (1.7 ) 138.8 Net income including noncontrolling interest 137.2 (0.7 ) 136.5 Net income attributable to partners 48.1 (0.7 ) 47.4 Nine Months Ended September 30, 2014 Operating revenue $ 245.8 $ — $ 245.8 Net income including noncontrolling interest and DCG Predecessor 75.2 — 75.2

Significant Accounting Polici26

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The contribution by Dominion to Dominion Midstream of the general partner interest in Cove Point and a portion of the Preferred Equity Interest is considered to be a reorganization of entities under common control. As a result, Dominion Midstream’s basis is equal to Dominion’s cost basis in the general partner interest in Cove Point and a portion of the Preferred Equity Interest. Dominion Midstream owns the general partner interest and controls Cove Point and therefore consolidates Cove Point. As such, Dominion Midstream’s investment in the Preferred Equity Interest and Cove Point's preferred equity interest are eliminated in consolidation. Dominion's retained common equity interest in Cove Point is reflected as noncontrolling interest. The DCG Acquisition is considered to be a reorganization of entities under common control. As a result, Dominion Midstream’s basis in DCG is equal to Dominion’s cost basis in the assets and liabilities of DCG. On April 1, 2015, DCG became a wholly-owned subsidiary of Dominion Midstream and is therefore consolidated by Dominion Midstream. The accompanying financial statements and related notes have been retrospectively adjusted to include the historical results and financial position of DCG beginning January 31, 2015, the inception date of common control. For the period prior to the closing of the Offering on October 20, 2014, the financial statements included in this Quarterly Report on Form 10-Q were derived from the financial statements and accounting records of Cove Point, as our predecessor for accounting purposes. The financial statements were prepared using Dominion's historical basis in the assets and liabilities of Cove Point and include all revenues, costs, assets and liabilities attributed to Cove Point. For the period subsequent to the closing of the Offering, the Consolidated Financial Statements represent the consolidated results of operations, financial position and cash flows of Dominion Midstream. The financial statements for all periods presented include costs for certain general, administrative and corporate expenses assigned by DRS or Dominion Payroll to Dominion Midstream and Cove Point on the basis of direct and allocated methods in accordance with Dominion Midstream's services agreements with DRS and Dominion Payroll and Cove Point's services agreement with DRS. Where costs incurred cannot be determined by specific identification, the costs are allocated based on the proportional level of effort devoted by DRS or Dominion Payroll resources that is attributable to the entities, determined by reference to number of employees, salaries and wages and other similar measures for the relevant DRS or Dominion Payroll department. Management believes the assumptions and methodologies underlying the allocation of general corporate overhead expenses are reasonable. Nevertheless, the Consolidated Financial Statements prior to the Offering may not include all of the actual expenses that would have been incurred had we been a stand-alone publicly traded partnership during the periods presented, and may not reflect our actual results of operations, financial position and cash flows had we been a stand-alone publicly traded partnership during the periods prior to the Offering.
Basis of Accounting	As permitted by the rules and regulations of the SEC, Dominion Midstream's accompanying unaudited Consolidated Financial Statements exclude certain footnote disclosures normally included in annual audited consolidated financial statements prepared in accordance with GAAP. These unaudited Consolidated Financial Statements should be read in conjunction with the Consolidated Financial Statements and Notes in Dominion Midstream’s Annual Report on Form 10-K for the year ended December 31, 2014.
Estimates	Dominion Midstream makes certain estimates and assumptions in preparing its Consolidated Financial Statements in accordance with GAAP. These estimates and assumptions affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses for the periods presented. Actual results may differ from those estimates.
Asset Retirement Obligations	Asset Retirement Obligations Dominion Midstream recognizes AROs at fair value as incurred or when sufficient information becomes available to determine a reasonable estimate of the fair value of future retirement activities to be performed. These amounts are generally capitalized as costs of the related tangible long-lived assets. Since relevant market information is not available, fair value is estimated using discounted cash flow analyses. At least annually, Dominion Midstream evaluates the key assumptions underlying its AROs including estimates of the amounts and timing of future cash flows associated with retirement activities. AROs are adjusted when significant changes in these assumptions are identified. Dominion Midstream reports accretion of AROs and depreciation on asset retirement costs associated with its natural gas pipeline assets as an adjustment to the related regulatory liabilities when revenue is recoverable from customers for AROs.
Investment in Equity Method Affiliate	Investment in Equity Method Affiliate Investments in affiliates where Dominion Midstream exercises significant influence over the operating activities of the entity, but does not control the entity, are accounted for using the equity method. Such investments are included in investment in equity method affiliate in the Consolidated Balance Sheets. Dominion Midstream records equity method adjustments in earnings from equity method affiliate in the Consolidated Statements of Income, including its proportionate share of investee income or loss and other adjustments required by the equity method. Dominion Midstream periodically evaluates its equity method investment to determine whether a decline in fair value should be considered other-than-temporary. If a decline in fair value of the investment is determined to be other-than-temporary, the investment is written down to its fair value at the end of the reporting period.

Net Income Per Limited Partne27

Net Income Per Limited Partner Unit (Tables)	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Schedule of Calculation of Earnings per Unit	The calculation of earnings per limited partner unit is as follows: Three Months Ended September 30, 2015 Nine Months Ended September 30, 2015 (millions) Net income attributable to partners $ 18.0 $ 47.4 Less: General partner allocation (1) — (0.7 ) Distributions declared on: Incentive distribution holder rights (2) — — Common units (3) 9.1 22.5 Subordinated units (3) 6.4 18.0 Total distributions declared 15.5 40.5 Undistributed earnings $ 2.5 $ 7.6 (1) See Note 2 for further information. (2) Dominion is a non-economic general partner that holds all of the IDRs. (3) On October 23, 2015, the Board of Directors of our general partner declared a quarterly cash distribution of $0.2000 per unit, totaling $15.5 million for the three months ended September 30, 2015. This distribution will be paid on November 13, 2015 to unitholders of record on November 3, 2015. The amount of distributions declared for the three months ended September 30, 2015 is based on the units outstanding at that date. On July 17, 2015, the Board of Directors of our general partner declared a quarterly cash distribution of $0.1875 per unit, totaling $12.9 million , for the three months ended June 30, 2015. This distribution was paid on August 14, 2015 to unitholders of record on August 4, 2015. On April 22, 2015, the Board of Directors of our general partner declared a quarterly cash distribution of $0.1750 per unit, totaling $12.1 million , for the three months ended March 31, 2015. This distribution was paid on May 15, 2015 to unitholders of record on May 5, 2015. Basic and diluted net income per limited partner unit Common Units Subordinated Units General Partner Total (millions, except for weighted average units and per unit data) Three Months Ended September 30, 2015 Distributions declared $ 9.1 $ 6.4 $ — $ 15.5 Undistributed earnings 1.3 1.2 — 2.5 Net income attributable to partners $ 10.4 $ 7.6 $ — $ 18.0 Weighted average units outstanding 37,279,747 31,972,789 Net income per limited partner unit $ 0.28 $ 0.24 Nine Months Ended September 30, 2015 General partner allocation $ — $ — $ (0.7 ) $ (0.7 ) Distributions declared 22.5 18.0 — 40.5 Undistributed earnings 4.0 3.6 — 7.6 Net income attributable to partners $ 26.5 $ 21.6 $ (0.7 ) $ 47.4 Weighted average units outstanding 35,470,133 31,972,789 Net income per limited partner unit $ 0.75 $ 0.67

Unit Activity (Tables)

Unit Activity (Tables)	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Schedule of Capital Units	Activity in the number of units was as follows: Common Public Dominion Subordinated General Partner Total (non-economic interest) Balance at December 31, 2014 20,127,322 11,847,789 31,972,789 — 63,947,900 Unit-based compensation 5,055 — — — 5,055 Units issued in connection with the DCG Acquisition — 5,112,139 — — 5,112,139 Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois 8,622,305 — — — 8,622,305 Dominion purchase of common units (1) (77,396 ) 77,396 — — — Balance at September 30, 2015 28,677,286 17,037,324 31,972,789 — 77,687,399 (1) These shares were purchased by Dominion as part of Dominion's program initiated in September 2015 to purchase from the market up to $50.0 million common units representing limited partner interests in Dominion Midstream by September 2016 at the discretion of Dominion's management. In October 2015, Dominion purchased approximately 478,000 additional common units.

Operating Revenue (Tables)

Operating Revenue (Tables)	9 Months Ended
	Sep. 30, 2015
Revenue Recognition [Abstract]
Operating Revenue	Dominion Midstream's operating revenue consists of the following: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (millions) Gas transportation and storage $ 78.1 $ 62.5 $ 231.7 $ 193.0 Other 25.0 3.2 55.2 52.8 Total operating revenue $ 103.1 $ 65.7 $ 286.9 $ 245.8

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Depreciation rates on utility property, plant and equipment are as follows: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (percent) Storage 2.38 2.38 2.38 2.39 Transmission 2.31 2.82 2.29 2.82 General and other 7.65 4.19 7.65 3.92 Major classes of property, plant and equipment and their respective balances for Dominion Midstream are as follows: September 30, 2015 December 31, 2014 (millions) Storage $ 875.0 $ 882.0 Transmission 669.1 323.9 Plant under construction 1,834.8 972.3 General and other 37.9 24.9 Total property, plant and equipment $ 3,416.8 $ 2,203.1

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in Dominion Midstream's carrying amount and segment allocation of goodwill are presented below: Dominion Energy Corporate and Other Total (millions) Nine Months Ended September 30, 2015 Beginning balance (1) $ 45.9 $ — $ 45.9 DCG Acquisition 249.6 — 249.6 Ending balance (1) $ 295.5 $ — $ 295.5 (1) There are no accumulated impairment losses.
Schedule of Finite-Lived Intangible Assets	The components of intangible assets are as follows: September 30, 2015 December 31, 2014 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization (millions) Software and other $ 31.0 $ 22.8 $ 6.5 $ 2.4 Licenses 11.0 3.3 11.0 3.0 Total $ 42.0 $ 26.1 $ 17.5 $ 5.4

Regulatory Assets and Liabili32

Regulatory Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2015
Regulated Operations [Abstract]
Schedule of Regulatory Assets	Regulatory assets and liabilities include the following: September 30, 2015 December 31, 2014 (millions) Regulatory assets: Unrecovered gas costs (1) $ 1.9 $ 1.5 Other 0.3 0.2 Regulatory assets-current 2.2 1.7 Income taxes recoverable through future rates (2) 2.7 2.5 Regulatory assets-non-current 2.7 2.5 Total regulatory assets $ 4.9 $ 4.2 Regulatory liabilities: Overrecovered gas costs (1) $ 0.2 $ 0.5 LNG cargo obligations (3) 3.3 3.0 Customer bankruptcy settlement (4) 3.0 — Other 0.3 0.1 Regulatory liabilities-current 6.8 3.6 Provision for future cost of removal (5) 47.9 33.0 Customer bankruptcy settlement (4) 21.1 — Other 0.6 0.5 Regulatory liabilities-non-current 69.6 33.5 Total regulatory liabilities $ 76.4 $ 37.1 (1) Reflects unrecovered/overrecovered gas costs, which are subject to annual filings with FERC. (2) Amounts to be recovered through future rates to pay income taxes that become payable by unitholders when rate revenue is provided to recover AFUDC-equity when such amounts are recovered through book depreciation. (3) Reflects obligations to the Import Shippers for LNG cargo received. See Note 9 to the Consolidated Financial Statements in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014 for further information. (4) Represents the balance of proceeds from the monetization of a bankruptcy claim acquired as part of the DCG Acquisition, which is being amortized into operating revenue through February 2024. (5) Rates charged to customers include a provision for the cost of future activities to remove assets that are expected to be incurred at the time of retirement.
Schedule of Regulatory Liabilities	Regulatory assets and liabilities include the following: September 30, 2015 December 31, 2014 (millions) Regulatory assets: Unrecovered gas costs (1) $ 1.9 $ 1.5 Other 0.3 0.2 Regulatory assets-current 2.2 1.7 Income taxes recoverable through future rates (2) 2.7 2.5 Regulatory assets-non-current 2.7 2.5 Total regulatory assets $ 4.9 $ 4.2 Regulatory liabilities: Overrecovered gas costs (1) $ 0.2 $ 0.5 LNG cargo obligations (3) 3.3 3.0 Customer bankruptcy settlement (4) 3.0 — Other 0.3 0.1 Regulatory liabilities-current 6.8 3.6 Provision for future cost of removal (5) 47.9 33.0 Customer bankruptcy settlement (4) 21.1 — Other 0.6 0.5 Regulatory liabilities-non-current 69.6 33.5 Total regulatory liabilities $ 76.4 $ 37.1 (1) Reflects unrecovered/overrecovered gas costs, which are subject to annual filings with FERC. (2) Amounts to be recovered through future rates to pay income taxes that become payable by unitholders when rate revenue is provided to recover AFUDC-equity when such amounts are recovered through book depreciation. (3) Reflects obligations to the Import Shippers for LNG cargo received. See Note 9 to the Consolidated Financial Statements in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014 for further information. (4) Represents the balance of proceeds from the monetization of a bankruptcy claim acquired as part of the DCG Acquisition, which is being amortized into operating revenue through February 2024. (5) Rates charged to customers include a provision for the cost of future activities to remove assets that are expected to be incurred at the time of retirement.

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2015
Asset Retirement Obligation Disclosure [Abstract]
Schedule of Change in Asset Retirement Obligation	The changes to AROs during 2014 and 2015 are as follows: Nine Months Ended Year Ended September 30, 2015 December 31, 2014 (millions) Beginning balance (1) $ 0.4 $ 0.4 DCG Acquisition 12.6 — Obligations settled during the period (0.9 ) — Revisions in estimated cash flows 1.7 — Accretion 0.4 — Ending balance (1) $ 14.2 $ 0.4 (1) Includes $0.1 million and $1.3 million reported in other current liabilities at December 31, 2014, and September 30, 2015, respectively.

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2015
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The imbalances with affiliates are provided below: September 30, 2015 December 31, 2014 (millions) Imbalances payable to affiliates $ 0.9 $ 2.5 Affiliated transactions are presented below: Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 (millions) Sales of natural gas transportation services to affiliates $ 0.6 $ 0.5 $ 1.7 $ 1.9 Purchased gas from affiliates 0.1 0.1 0.4 0.5 Goods and services provided by affiliates to Dominion Midstream (1) 8.6 3.9 25.3 11.5 (1) Includes $3.4 million and $8.9 million of capitalized expenditures for the three and nine months ended September 30, 2015, respectively, and $1.8 million and $5.5 million for the three and nine months ended September 30, 2014, respectively.

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	For the nine months ended September 30, 2015 and 2014, the statutory U.S. federal income tax rate reconciles to the effective income tax rate as follows: Nine Months Ended September 30, 2015 2014 U.S. statutory rate 35.0 % 35.0 % Partnership income not subject to income taxes (1) (33.6 ) — Increases resulting from: State taxes, net of federal benefit (2) 0.1 3.2 Effective tax rate 1.5 % 38.2 % (1) Reflects the pass-through entity status of Dominion Midstream, including the operations of DCG subsequent to the DCG Acquisition, and Cove Point. (2) 2015 amounts are attributable to the operations of DCG prior to the DCG Acquisition, and 2014 amounts are attributable to Cove Point.

Operating Segment (Tables)

Operating Segment (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following table presents segment information pertaining to Dominion Midstream's operations: Dominion Energy Corporate and Other Total (millions) Three Months Ended September 30, 2015 Operating revenue $ 103.1 $ — $ 103.1 Net income including noncontrolling interest and DCG Predecessor 48.8 — 48.8 Net income attributable to partners 18.0 — 18.0 Three Months Ended September 30, 2014 Operating revenue $ 65.7 $ — $ 65.7 Net income including noncontrolling interest and DCG Predecessor 26.4 — 26.4 Nine Months Ended September 30, 2015 Operating revenue $ 286.9 $ — $ 286.9 Net income including noncontrolling interest and DCG Predecessor 140.5 (1.7 ) 138.8 Net income including noncontrolling interest 137.2 (0.7 ) 136.5 Net income attributable to partners 48.1 (0.7 ) 47.4 Nine Months Ended September 30, 2014 Operating revenue $ 245.8 $ — $ 245.8 Net income including noncontrolling interest and DCG Predecessor 75.2 — 75.2

Description of Business and B37

Description of Business and Basis of Presentation (Details)	Sep. 29, 2015mi	Apr. 01, 2015mi	Oct. 20, 2014shares	Sep. 30, 2015
Iroquois Gas Transmission System, LP | Partnership Interest
Subsidiary, Sale of Stock [Line Items]
Length of FERC regulated interstate natural gas pipeline (nearly 1,500 miles) | mi	416
Partnership interest percentage acquired in Iroquois	25.93%			25.93%
DCG | Affiliates | Dominion
Subsidiary, Sale of Stock [Line Items]
Length of FERC regulated interstate natural gas pipeline (nearly 1,500 miles) | mi		1,500
Common Units | IPO
Subsidiary, Sale of Stock [Line Items]
Number of units issued			20,125,000
Common Units | Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Number of units issued			2,625,000

Acquisitions -DCG (Details)

Acquisitions -DCG (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 01, 2015	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2015
Business Acquisition [Line Items]
Equity contributions				$ 614
Dominion | DCG
Business Acquisition [Line Items]
Equity contributions				$ 2.3
Dominion | DCG | Affiliates
Business Acquisition [Line Items]
Total consideration	$ 500.8
Total transaction costs associated with DCG acquisition		$ 1.5
Historical cost of assets and liabilities of DCG	$ 501.6
Dominion | DCG | General Partner | Affiliates
Business Acquisition [Line Items]
Equity contributions		0.7
Dominion | DCG | Other Operations and Maintenance Expense | Affiliates
Business Acquisition [Line Items]
Total transaction costs associated with DCG acquisition		$ 0.5	$ 1.5
Dominion | DCG | Partnership Interest | Affiliates
Business Acquisition [Line Items]
Number of common units issued	5,112,139
Value of common units issued	$ 200
Number of trading days	10 days
Price per unit	$ 39.12
Dominion | DCG | Partnership Interest | General Partner | Affiliates
Business Acquisition [Line Items]
Equity contributions			$ 0.7
Dominion | DCG | Notes Payable | Senior Unsecured Promissory Note Payable | Affiliates
Business Acquisition [Line Items]
Term of senior unsecured promissory note payable	2 years
Senior unsecured promissory note payable	$ 300.8
Annual interest rate (percentage)	0.60%

Acquisitions -Iroquois (Details

Acquisitions -Iroquois (Details) - USD ($)	Sep. 29, 2015	Sep. 28, 2015	Sep. 30, 2015
Schedule of Equity Method Investments [Line Items]
Allocation of DCG Predecessor investment			$ 216,000,000
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			8,622,305
Partnership Interest | Iroquois Gas Transmission System, LP
Schedule of Equity Method Investments [Line Items]
Number of trading days	5 years
Price per unit	$ 33.23
Partnership interest percentage acquired in Iroquois	25.93%		25.93%
Value of Iroquois investment	$ 216,400,000
External transaction costs	$ 400,000
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois	8,622,305
Duration of lockup period	1 year
NG | Partnership Interest | Iroquois Gas Transmission System, LP
Schedule of Equity Method Investments [Line Items]
Partnership interest percentage purchased		20.40%
Allocation of DCG Predecessor investment	$ 6,783,373
NJNR | Partnership Interest | Iroquois Gas Transmission System, LP
Schedule of Equity Method Investments [Line Items]
Partnership interest percentage purchased		5.53%
Allocation of DCG Predecessor investment	$ 1,838,932

Net Income Per Limited Partne40

Net Income Per Limited Partner Unit (Details) - USD ($) $ / shares in Units, $ in Millions		Oct. 23, 2015	Jul. 17, 2015	Apr. 22, 2015	Sep. 30, 2015	Sep. 30, 2015
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Potentially dilutive common or subordinated units outstanding						0
Net income attributable to partners					$ 18	$ 47.4
General partner allocation	[1]				0	(0.7)
Incentive distribution holder rights	[2]				0	0
Distribution declared on Common and Subordinated unitholders			$ 12.9	$ 12.1
Total distributions declared					15.5	40.5
Undistributed earnings					2.5	7.6
Quarterly distribution per unit			$ 0.1875	$ 0.1750
General Partner
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income attributable to partners					0	(0.7)
General partner allocation						(0.7)
Total distributions declared					0	0
Undistributed earnings					0	0
Common Units
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Distribution declared on Common and Subordinated unitholders	[3]				$ 9.1	$ 22.5
Net income per limited partner unit (basic and diluted)					$ 0.28	$ 0.75
Common Units | Limited Partners
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income attributable to partners					$ 10.4	$ 26.5
General partner allocation						0
Total distributions declared					9.1	22.5
Undistributed earnings					$ 1.3	$ 4
Weighted average units outstanding					37,279,747	35,470,133
Net income per limited partner unit (basic and diluted)					$ 0.28	$ 0.75
Subordinated Units
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Distribution declared on Common and Subordinated unitholders	[3]				$ 6.4	$ 18
Net income per limited partner unit (basic and diluted)					$ 0.24	$ 0.67
Subordinated Units | Limited Partners
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income attributable to partners					$ 7.6	$ 21.6
General partner allocation						0
Total distributions declared					6.4	18
Undistributed earnings					$ 1.2	$ 3.6
Weighted average units outstanding					31,972,789	31,972,789
Net income per limited partner unit (basic and diluted)					$ 0.24	$ 0.67
Subsequent Event
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Distribution declared on Common and Subordinated unitholders		$ 15.5
Quarterly distribution per unit		$ 0.2000
[1]	See Note 2 for further information.
[2]	Dominion is a non-economic general partner that holds all of the IDRs.
[3]	On October 23, 2015, the Board of Directors of our general partner declared a quarterly cash distribution of $0.2000 per unit, totaling $15.5 million for the three months ended September 30, 2015. This distribution will be paid on November 13, 2015 to unitholders of record on November 3, 2015. The amount of distributions declared for the three months ended September 30, 2015 is based on the units outstanding at that date.On July 17, 2015, the Board of Directors of our general partner declared a quarterly cash distribution of $0.1875 per unit, totaling $12.9 million, for the three months ended June 30, 2015. This distribution was paid on August 14, 2015 to unitholders of record on August 4, 2015. On April 22, 2015, the Board of Directors of our general partner declared a quarterly cash distribution of $0.1750 per unit, totaling $12.1 million, for the three months ended March 31, 2015. This distribution was paid on May 15, 2015 to unitholders of record on May 5, 2015.

Unit Activity (Details)

Unit Activity (Details) - USD ($)		1 Months Ended	9 Months Ended
		Oct. 31, 2015	Sep. 30, 2015
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at December 31, 2014		77,687,399	63,947,900
Unit-based compensation			5,055
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			8,622,305
Dominion purchase of common units	[1]		0
Balance at September 30, 2015			77,687,399
DCG
Increase (Decrease) in Partners' Capital [Roll Forward]
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			5,112,139
Dominion
Increase (Decrease) in Partners' Capital [Roll Forward]
Value of shares to be repurchased (up to $50.0 million)			$ 50,000,000
Dominion | Subsequent Event
Increase (Decrease) in Partners' Capital [Roll Forward]
Dominion purchase of common units		478,000
General Partner Dominion (non-economic interest) | General Partner Dominion (non-economic interest) | Dominion
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at December 31, 2014		0	0
Unit-based compensation			0
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			0
Dominion purchase of common units	[1]		0
Balance at September 30, 2015			0
General Partner Dominion (non-economic interest) | General Partner Dominion (non-economic interest) | Dominion | DCG
Increase (Decrease) in Partners' Capital [Roll Forward]
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			0
Common Units | Common Unitholders and Subordinated Unitholder | Limited Partners
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at December 31, 2014		28,677,286	20,127,322
Unit-based compensation			5,055
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			8,622,305
Dominion purchase of common units	[1]		(77,396)
Balance at September 30, 2015			28,677,286
Common Units | Common Unitholders and Subordinated Unitholder | Limited Partners | DCG
Increase (Decrease) in Partners' Capital [Roll Forward]
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			0
Common Units | Common Unitholders and Subordinated Unitholder | Limited Partners | Dominion
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at December 31, 2014		17,037,324	11,847,789
Unit-based compensation			0
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			0
Dominion purchase of common units	[1]		77,396
Balance at September 30, 2015			17,037,324
Common Units | Common Unitholders and Subordinated Unitholder | Limited Partners | Dominion | DCG
Increase (Decrease) in Partners' Capital [Roll Forward]
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			5,112,139
Subordinated Units | Common Unitholders and Subordinated Unitholder | Limited Partners | Dominion
Increase (Decrease) in Partners' Capital [Roll Forward]
Balance at December 31, 2014		31,972,789	31,972,789
Unit-based compensation			0
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			0
Dominion purchase of common units	[1]		0
Balance at September 30, 2015			31,972,789
Subordinated Units | Common Unitholders and Subordinated Unitholder | Limited Partners | Dominion | DCG
Increase (Decrease) in Partners' Capital [Roll Forward]
Units issued in connection with the acquisition of a noncontrolling partnership interest in Iroquois			0
[1]	These shares were purchased by Dominion as part of Dominion's program initiated in September 2015 to purchase from the market up to $50.0 million common units representing limited partner interests in Dominion Midstream by September 2016 at the discretion of Dominion's management. In October 2015, Dominion purchased approximately 478,000 additional common units.

Operating Revenue (Details)

Operating Revenue (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Public Utilities, General Disclosures [Line Items]
Gas transportation and storage		$ 78.1		$ 231.7
Other		25		55.2
Total operating revenue	[1]	$ 103.1		$ 286.9
Predecessor
Public Utilities, General Disclosures [Line Items]
Gas transportation and storage			$ 62.5		$ 193
Other			3.2		52.8
Total operating revenue	[1]		$ 65.7		$ 245.8
[1]	See Note 17 for amounts attributable to related parties.

Equity Method Investments (Deta

Equity Method Investments (Details) - USD ($) $ in Millions	Sep. 30, 2015	Sep. 29, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Investment in Equity Method Affiliate	$ 216.4		$ 0
Iroquois Gas Transmission System, LP | Partnership Interest
Schedule of Equity Method Investments [Line Items]
Partnership interest percentage acquired in Iroquois	25.93%	25.93%
Investment in Equity Method Affiliate	$ 216.4
Amount that investment exceeded its share of underlying equity	$ 121.7

Property, Plant and Equipment -

Property, Plant and Equipment -Schedule of Property Plant And Equipment (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 3,416.8		$ 2,203.1
Capitalized interest costs and AFUDC	1.4
Storage
Property, Plant and Equipment [Line Items]
Property, plant and equipment	875		882
Transmission
Property, Plant and Equipment [Line Items]
Property, plant and equipment	669.1		323.9
Plant under construction
Property, Plant and Equipment [Line Items]
Property, plant and equipment	1,834.8		972.3
General and other
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 37.9		$ 24.9
Predecessor
Property, Plant and Equipment [Line Items]
Capitalized interest costs and AFUDC		$ 0.1

Property, Plant and Equipment45

Property, Plant and Equipment -Schedule of Depreciation Rates on Utility Property Plant and Equipment (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Storage
Property, Plant and Equipment [Line Items]
Depreciation rates on utility property, plant and equipment	2.38%		2.38%
Transmission
Property, Plant and Equipment [Line Items]
Depreciation rates on utility property, plant and equipment	2.31%		2.29%
General and other
Property, Plant and Equipment [Line Items]
Depreciation rates on utility property, plant and equipment	7.65%		7.65%
Predecessor | Storage
Property, Plant and Equipment [Line Items]
Depreciation rates on utility property, plant and equipment		2.38%		2.39%
Predecessor | Transmission
Property, Plant and Equipment [Line Items]
Depreciation rates on utility property, plant and equipment		2.82%		2.82%
Predecessor | General and other
Property, Plant and Equipment [Line Items]
Depreciation rates on utility property, plant and equipment		4.19%		3.92%

Goodwill and Intangible Asset46

Goodwill and Intangible Assets -Schedule of Goodwill (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 45.9	[1]
DCG Acquisition	249.6
Ending balance	295.5	[1]
Operating Segments | Dominion Energy
Goodwill [Roll Forward]
Beginning balance	45.9	[1]
DCG Acquisition	249.6
Ending balance	295.5	[1]
Operating Segments | Corporate and Other
Goodwill [Roll Forward]
Beginning balance	0	[1]
DCG Acquisition	0
Ending balance	$ 0	[1]
[1]	There are no accumulated impairment losses.

Goodwill and Intangible Asset47

Goodwill and Intangible Assets -Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 0.6		$ 1.5
Computer Software, Intangible Asset | DCG
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period			5 years
Predecessor
Finite-Lived Intangible Assets [Line Items]
Amortization expense		$ 0.1		$ 0.4

Goodwill and Intangible Asset48

Goodwill and Intangible Assets -Schedule of Components of Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 42	$ 17.5
Accumulated Amortization	26.1	5.4
Software and other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	31	6.5
Accumulated Amortization	22.8	2.4
Licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	11	11
Accumulated Amortization	$ 3.3	$ 3

Regulatory Assets and Liabili49

Regulatory Assets and Liabilities (Regulatory Assets) (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2015	Dec. 31, 2014
Regulatory Assets [Line Items]
Regulatory assets-current		$ 2.2	$ 1.7
Regulatory assets-non-current		2.7	2.5
Total regulatory assets		4.9	4.2
Past expenditures in which no return is expected		$ 2.2
Recovery period of expenditures		1 year
Unrecovered gas costs
Regulatory Assets [Line Items]
Regulatory assets-current	[1]	$ 1.9	1.5
Other
Regulatory Assets [Line Items]
Regulatory assets-current		0.3	0.2
Income taxes recoverable through future rates
Regulatory Assets [Line Items]
Regulatory assets-non-current	[2]	$ 2.7	$ 2.5
[1]	Reflects unrecovered/overrecovered gas costs, which are subject to annual filings with FERC.
[2]	Amounts to be recovered through future rates to pay income taxes that become payable by unitholders when rate revenue is provided to recover AFUDC-equity when such amounts are recovered through book depreciation.

Regulatory Assets and Liabili50

Regulatory Assets and Liabilities (Regulatory Liabilities) (Details) - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Regulatory Liabilities [Line Items]
Regulatory liabilities-current		$ 6.8	$ 3.6
Regulatory liabilities-non-current		69.6	33.5
Total regulatory liabilities		76.4	37.1
Overrecovered gas costs
Regulatory Liabilities [Line Items]
Regulatory liabilities-current	[1]	0.2	0.5
LNG cargo obligations
Regulatory Liabilities [Line Items]
Regulatory liabilities-current	[2]	3.3	3
Customer bankruptcy settlement
Regulatory Liabilities [Line Items]
Regulatory liabilities-current	[3]	3	0
Regulatory liabilities-non-current	[3]	21.1	0
Other
Regulatory Liabilities [Line Items]
Regulatory liabilities-current		0.3	0.1
Regulatory liabilities-non-current		0.6	0.5
Provision for future cost of removal
Regulatory Liabilities [Line Items]
Regulatory liabilities-non-current	[4]	$ 47.9	$ 33
[1]	Reflects unrecovered/overrecovered gas costs, which are subject to annual filings with FERC.
[2]	Reflects obligations to the Import Shippers for LNG cargo received. See Note 9 to the Consolidated Financial Statements in Dominion Midstream's Annual Report on Form 10-K for the year ended December 31, 2014 for further information.
[3]	Represents the balance of proceeds from the monetization of a bankruptcy claim acquired as part of the DCG Acquisition, which is being amortized into operating revenue through February 2024.
[4]	Rates charged to customers include a provision for the cost of future activities to remove assets that are expected to be incurred at the time of retirement.

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) - FERC - USD ($) $ in Millions	1 Months Ended		3 Months Ended
	Oct. 31, 2015	Apr. 30, 2014	Jun. 30, 2013
Edgemoor Project | DCG
Public Utilities, General Disclosures [Line Items]
Amount of project			$ 35
Columbia to Eastover Project | DCG
Public Utilities, General Disclosures [Line Items]
Amount of project		$ 35
St Charles Transportation Project | Subsequent Event | Cove Point
Public Utilities, General Disclosures [Line Items]
Amount of project	$ 30
Keys Energy Project | Subsequent Event | Cove Point
Public Utilities, General Disclosures [Line Items]
Amount of project	$ 40

Asset Retirement Obligations (D

Asset Retirement Obligations (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 0.4
DCG Acquisition	12.6	$ 0
Obligations settled during the period	(0.9)	0
Revisions in estimated cash flows	1.7	0
Accretion	0.4	0
Ending balance	14.2	0.4
Other Current Liabilities
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO reported in other current liabilities	$ 1.3	0.1
Predecessor
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		$ 0.4

Variable Interest Entities -Iro

Variable Interest Entities -Iroquois (Details)	9 Months Ended
	Sep. 30, 2015
Iroquois Gas Transmission System, LP | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Membership interest percentage owned	25.93%

Variable Interest Entities -DRS

Variable Interest Entities -DRS and Dominion Payroll (Details) - Affiliates - Services provided by DRS - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Dominion Midstream
Variable Interest Entity [Line Items]
Services purchased	$ 6.8		$ 20.1
Amounts due from Dominion Midstream to DRS and Dominion Payroll	$ 1.8		$ 1.8		$ 1.7
Cove Point
Variable Interest Entity [Line Items]
Services purchased		$ 3.1		$ 9.2

Affiliated Long-Term Debt (Deta

Affiliated Long-Term Debt (Details) - Senior Unsecured Promissory Note Payable - Notes Payable - Dominion - Affiliates - USD ($)	Apr. 01, 2015	Sep. 30, 2015	Sep. 30, 2015
Debt Instrument [Line Items]
Interest charges related to borrowing from Dominion		$ 500,000	$ 1,000,000
Fair Value, Inputs, Level 2
Debt Instrument [Line Items]
Fair value of outstanding debt		285,400,000	285,400,000
Payables to Affiliates
Debt Instrument [Line Items]
Accrued interest payable to Dominion		$ 500,000	$ 500,000
DCG
Debt Instrument [Line Items]
Term of senior unsecured promissory note payable	2 years
Principal amount	$ 300,800,000
Annual interest rate (percentage)	0.60%

Commitments and Contingencies (

Commitments and Contingencies (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2015USD ($)
Other Operations and Maintenance Expense
Other Commitments [Line Items]
Rental expense	$ 700,000	$ 2,100,000
Surety Bond
Other Commitments [Line Items]
Total amount of commitment	10,900,000	$ 10,900,000
Maximum
Other Commitments [Line Items]
Operating lease arrangements term		1 year
Annual Contributions to Cove Point Natural Heritage Trust
Other Commitments [Line Items]
Total amount of commitment	300,000	$ 300,000
Annual Contributions to Cove Point Natural Heritage Trust | Minimum
Other Commitments [Line Items]
Total amount of commitment	$ 0	$ 0

Credit Risk (Details)

Credit Risk (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)customer	Sep. 30, 2014customer	Sep. 30, 2015USD ($)customer	Sep. 30, 2014customer
Customer Concentration Risk | Sales Revenue, Net
Concentration Risk [Line Items]
Number of customers			70
Customer Concentration Risk | Sales Revenue, Net | Two Largest Customers
Concentration Risk [Line Items]
Number of customers	2		2
Percentage of total transportation and storage revenues	71.00%		71.00%
Customer Concentration Risk | Sales Revenue, Net | Largest Customer
Concentration Risk [Line Items]
Percentage of total transportation and storage revenues	56.00%		57.00%
Credit Concentration Risk | Accounts Receivable
Concentration Risk [Line Items]
Provision for credit losses (less than $0.1 million) | $	$ 0.1		$ 0.1
Predecessor | Customer Concentration Risk | Sales Revenue, Net | Largest Customer
Concentration Risk [Line Items]
Percentage of total transportation and storage revenues		73.00%		73.00%
Predecessor | Customer Concentration Risk | Sales Revenue, Net | Three Largest Customers
Concentration Risk [Line Items]
Number of customers		3		3
Percentage of total transportation and storage revenues		94.00%		94.00%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)

Apr. 01, 2015

Oct. 20, 2014

Oct. 31, 2015

Feb. 28, 2015

Mar. 31, 2014

Sep. 30, 2015

Sep. 30, 2014

Sep. 30, 2015

Sep. 30, 2015

Sep. 30, 2014

Oct. 19, 2014

Dec. 31, 2014

Related Party Transaction [Line Items]

Equity contributions

$ 614,000,000

Imbalances payable to affiliates

[1]

$ 1,100,000

$ 1,100,000

1,100,000

$ 2,700,000

Dominion | DCG

Related Party Transaction [Line Items]

Equity contributions

2,300,000

Affiliates

Related Party Transaction [Line Items]

Sales of natural gas transportation services to affiliates

600,000

1,700,000

Capital expenditures

3,400,000

8,900,000

Imbalances payable to affiliates

900,000

900,000

900,000

2,500,000

Affiliates | Pension and Other Postretirement Benefit Liabilities

Related Party Transaction [Line Items]

Amounts due to Dominion associated with benefit plans

4,900,000

4,900,000

4,900,000

4,400,000

Affiliates | Predecessor

Related Party Transaction [Line Items]

Sales of natural gas transportation services to affiliates

$ 500,000

$ 1,900,000

Capital expenditures

1,800,000

5,500,000

Affiliates | Cove Point | Predecessor

Related Party Transaction [Line Items]

Equity contributions

$ 20,000,000

Affiliates | Dominion | DCG

Related Party Transaction [Line Items]

Total transaction costs associated with DCGT acquisition

1,500,000

Affiliates | Dominion | DCG | General Partner Dominion (non-economic interest)

Related Party Transaction [Line Items]

Equity contributions

700,000

Affiliates | Dominion | DCG | Partnership Interest

Related Party Transaction [Line Items]

Equity contribution from Dominion to relieve payables to affiliates

$ 1,000,000

Affiliates | Dominion | DCG | Partnership Interest | General Partner Dominion (non-economic interest)

Related Party Transaction [Line Items]

Equity contributions

700,000

Affiliates | Reimbursement of transition services costs by affiliate | DCG

Related Party Transaction [Line Items]

Goods and services provided by affiliates

1,000,000

2,100,000

Affiliates | Purchased gas from affiliates

Related Party Transaction [Line Items]

Purchased gas from affiliates

100,000

400,000

Affiliates | Purchased gas from affiliates | Predecessor

Related Party Transaction [Line Items]

Purchased gas from affiliates

100,000

500,000

Affiliates | Goods and services provided by affiliates to Cove Point

Related Party Transaction [Line Items]

Goods and services provided by affiliates

[2]

8,600,000

25,300,000

Affiliates | Goods and services provided by affiliates to Cove Point | Predecessor

Related Party Transaction [Line Items]

Goods and services provided by affiliates

[2]

$ 3,900,000

$ 11,500,000

Affiliates | Credit Facility with Dominion | Line of Credit

Related Party Transaction [Line Items]

Amount outstanding against the credit facility

5,900,000

$ 5,900,000

$ 5,900,000

$ 0

Termination notice period

90 days

Interest charges related to borrowing from Dominion

100,000

$ 100,000

Affiliates | Credit Facility with Dominion | IPO | Line of Credit

Related Party Transaction [Line Items]

Borrowing capacity

$ 300,000,000

Affiliates | Tax Sharing Agreement | DCG | Equity contribution with Dominion related to income taxes

Related Party Transaction [Line Items]

Settlement of income taxes payable and net deferred income taxes through an equity transaction with Dominion

$ 13,400,000

Affiliates | Tax Sharing Agreement | Cove Point | Equity contribution with Dominion related to income taxes

Related Party Transaction [Line Items]

Equity contribution from Dominion to relieve payables to affiliates

$ 147,900,000

Affiliates | Tax Sharing Agreement | Cove Point | Predecessor | Equity contribution with Dominion related to income taxes

Related Party Transaction [Line Items]

Equity contribution from Dominion to relieve payables to affiliates

$ 1,200,000

Affiliates | Capital Expenditures related to Liquefaction Project | Cove Point

Related Party Transaction [Line Items]

Contribution to fund capital expenditures

$ 341,500,000

$ 613,300,000

Affiliates | Capital Expenditures related to Liquefaction Project | Cove Point | Subsequent Event

Related Party Transaction [Line Items]

Contribution to fund capital expenditures

$ 113,200,000

Affiliates | Contribution to Fund Operations | DCG | Predecessor

Related Party Transaction [Line Items]

Contribution to fund capital expenditures

$ 1,300,000

[1]

See Note 17 for amounts attributable to related parties.

[2]

Includes $3.4 million and $8.9 million of capitalized expenditures for the three and nine months ended September 30, 2015, respectively, and $1.8 million and $5.5 million for the three and nine months ended September 30, 2014, respectively.

Income Taxes (Details)

Income Taxes (Details)		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014
Income Taxes [Line Items]
U.S. statutory rate		35.00%
Income not subject to income taxes	[1]	(33.60%)
Increases resulting from:
State taxes, net of federal benefit	[2]	0.10%
Effective tax rate		1.50%
Predecessor
Income Taxes [Line Items]
U.S. statutory rate			35.00%
Income not subject to income taxes	[1]		(0.00%)
Increases resulting from:
State taxes, net of federal benefit	[2]		3.20%
Effective tax rate			38.20%
[1]	Reflects the pass-through entity status of Dominion Midstream, including the operations of DCG subsequent to the DCG Acquisition, and Cove Point.
[2]	2015 amounts are attributable to the operations of DCG prior to the DCG Acquisition, and 2014 amounts are attributable to Cove Point.

Operating Segment (Schedule of

Operating Segment (Schedule of Segment Reporting Information, by Segment) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Operating revenue	[1]	$ 103.1		$ 286.9
Net income including noncontrolling interest and DCG Predecessor		48.8		138.8
Net income including noncontrolling interest		48.8		136.5
Net income attributable to partners		18		47.4
Predecessor
Segment Reporting Information [Line Items]
Operating revenue	[1]		$ 65.7		$ 245.8
Net income including noncontrolling interest and DCG Predecessor			26.4		75.2
Operating Segments | Dominion Energy
Segment Reporting Information [Line Items]
Operating revenue		103.1		286.9
Net income including noncontrolling interest and DCG Predecessor		48.8		140.5
Net income including noncontrolling interest				137.2
Net income attributable to partners		18		48.1
Operating Segments | Dominion Energy | Predecessor
Segment Reporting Information [Line Items]
Operating revenue			65.7		245.8
Net income including noncontrolling interest and DCG Predecessor			26.4		75.2
Operating Segments | Corporate and Other
Segment Reporting Information [Line Items]
Operating revenue		0		0
Net income including noncontrolling interest and DCG Predecessor		0		(1.7)
Net income including noncontrolling interest				(0.7)
Net income attributable to partners		$ 0		$ (0.7)
Operating Segments | Corporate and Other | Predecessor
Segment Reporting Information [Line Items]
Operating revenue			0		0
Net income including noncontrolling interest and DCG Predecessor			$ 0		$ 0
[1]	See Note 17 for amounts attributable to related parties.