Washington Gas Light (WGLCP) 10-Q 31 Oct 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - $ / shares	9 Months Ended
	Sep. 30, 2019	Oct. 30, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	Washington Gas Light Company
Entity Central Index Key	0000104819
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		46,479,536
Par Value Per Share	$ 1

Balance Sheet

Balance Sheet - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment
At original cost	$ 5,997,026	$ 5,702,927
Accumulated depreciation and amortization	(1,580,141)	(1,513,590)
Net property, plant and equipment	4,416,885	4,189,337
Current Assets
Cash and cash equivalents	1	6,082
Receivables
Accounts receivable	175,571	292,871
Gas costs and other regulatory assets	11,100	6,020
Unbilled revenues	66,230	189,497
Allowance for doubtful accounts	(25,739)	(29,461)
Net receivables	227,162	458,927
Materials and supplies—principally at average cost	19,870	19,727
Storage gas	92,450	103,929
Prepaid taxes	30,984	27,193
Other prepayments	22,035	28,232
Receivables from associated companies	8,800	4,819
Derivatives	3,562	19,488
Other	4,378	20,347
Total current assets	409,242	688,744
Deferred Charges and Other Assets
Gas costs	91,913	141,636
Pension and other post-retirement benefits	77,200	86,493
Other	82,116	99,105
Prepaid post-retirement benefits	254,837	249,462
Right of use asset	40,966	0
Derivatives	8,462	11,318
Other	50,098	50,490
Total deferred charges and other assets	605,592	638,504
Total Assets	5,431,719	5,516,585
Capitalization
Common shareholder’s equity	1,539,947	1,562,573
Preferred stock	28,173	28,173
Long-term debt	1,331,116	1,035,033
Total capitalization	2,899,236	2,625,779
Current Liabilities
Current maturities of long-term debt	50,000	50,000
Notes payable and project financing	117,000	311,460
Accounts payable and other accrued liabilities	182,784	288,376
Wages payable	20,947	22,629
Accrued interest	4,193	14,504
Dividends declared	0	24,567
Customer deposits and advance payments	42,859	54,370
Gas costs and other regulatory liabilities	71,978	75,151
Accrued taxes	35,281	28,451
Payables to associated companies	68,066	95,228
Operating lease liability	5,632	0
Derivatives	12,775	20,295
Other	7,266	7,507
Total current liabilities	618,781	992,538
Deferred Credits
Unamortized investment tax credits	2,739	3,233
Deferred income taxes	431,408	454,248
Accrued pensions and benefits	165,365	156,210
Asset retirement obligations	308,470	300,769
Regulatory liabilities
Accrued asset removal costs	245,334	264,556
Other post-retirement benefits	109,934	121,345
Excess deferred taxes and other	400,248	431,913
Operating lease liability	54,686	0
Derivatives	105,101	116,847
Other	90,417	49,147
Total deferred credits	1,913,702	1,898,268
Commitments and Contingencies (Note 10)
Total Capitalization and Liabilities	$ 5,431,719	$ 5,516,585

Statement of Operations

Statement of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
OPERATING REVENUES	$ 122,305	$ 139,041	$ 914,442	$ 870,593
OPERATING EXPENSES
Utility cost of gas	33,433	20,939	331,285	282,298
Operation and maintenance	101,195	282,793	300,433	461,808
Depreciation and amortization	34,383	33,914	106,623	101,425
General taxes and other assessments	26,344	26,857	106,709	108,195
Total Operating Expenses	195,355	364,503	845,050	953,726
OPERATING INCOME	(73,050)	(225,462)	69,392	(83,133)
Other income (expense) —net	3,533	(10,408)	7,298	(8,621)
Interest expense	15,575	14,404	45,092	43,531
INCOME (LOSS) BEFORE INCOME TAXES	(85,092)	(250,274)	31,598	(135,285)
INCOME TAX EXPENSE (BENEFIT)	(19,293)	(69,121)	4,992	(50,717)
NET INCOME (LOSS)	(65,799)	(181,153)	26,606	(84,568)
Dividends on preferred stock	0	330	660	990
NET INCOME (LOSS) APPLICABLE TO COMMON STOCK	$ (65,799)	$ (181,483)	$ 25,946	$ (85,558)

Statement of Comprehensive Inco

Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
NET INCOME (LOSS)	$ (65,799)	$ (181,153)	$ 26,606	$ (84,568)
Pension and other post-retirement benefit plans
Change in prior service cost	(163)	145	(486)	(401)
Change in actuarial net gain (loss)	392	4,737	2,448	5,797
Total pension and other post-retirement benefit plans	229	4,882	1,962	5,396
INCOME TAX EXPENSE RELATED TO OTHER COMPREHENSIVE INCOME	(713)	2,753	534	2,896
OTHER COMPREHENSIVE INCOME (LOSS)	942	2,129	1,428	2,500
COMPREHENSIVE INCOME (LOSS)	$ (64,857)	$ (179,024)	$ 28,034	$ (82,068)

Statements of Cash Flows

Statements of Cash Flows $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)
OPERATING ACTIVITIES
Net income	$ 26,606	$ (84,568)
ADJUSTMENTS TO RECONCILE NET INCOME TO NET CASH PROVIDED BY OPERATING ACTIVITIES
Depreciation and amortization	106,623	101,425
Amortization of:
Other regulatory assets and liabilities—net	5,583	5,283
Debt related costs	1,128	1,179
Deferred income taxes-net	7,087	(33,821)
Accrued/deferred pension and other post-retirement benefit cost	(949)	8,729
Compensation expense related to stock-based awards	2,275	14,549
Provision for doubtful accounts	10,615	16,296
Impairment Charge on Reclassified Assets	0	37,969
Unrealized (gain) loss on derivative contracts	(128)	(11,825)
Accumulated Deferred Investment Tax Credit	2,739
Amortization of investment tax credits	(494)	(523)
Other non-cash charges (credits)—net	1,226	(2,253)
Changes in operating assets and liabilities (Note 15)	94,572	98,314
Net Cash Provided by Operating Activities	254,144	150,754
FINANCING ACTIVITIES
Capital contribution from parent	0	302,728
Proceeds from (Repayments of) Debt	298,482	0
Debt issuance costs	(2,756)	(130)
Notes payable issued (retired)—net	(179,000)	(66,998)
Capital contribution from parent	0	53,018
Dividends on common stock and preferred stock	(75,227)	(66,742)
Net Cash Provided by Financing Activities	41,499	221,876
INVESTING ACTIVITIES
Capital expenditures (excluding AFUDC)	(318,895)	(317,537)
Proceeds from Insurance Settlement, Investing Activities	0	3,238
Net Cash Used in Investing Activities	(318,895)	(314,299)
INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(23,252)	58,331
Cash, Cash Equivalents, and Restricted Cash at Beginning of the Period	71,423	6,652
Cash, Cash equivalents and Restricted Cash at End of the Period	$ 48,171	$ 64,983

Accounting Policies

Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Business Description and Accounting Policies [Text Block]	ACCOUNTING POLICIES Basis of Presentation Washington Gas is an indirect, majority owned subsidiary of, among other entities, AltaGas and WGL. On July 6, 2018, a merger of WGL into AltaGas was consummated (the Merger). In connection with the Merger, WGL, the former parent entity of Washington Gas, formed a wholly owned subsidiary, Wrangler SPE LLC (Wrangler), a bankruptcy remote, special purpose entity to own the common stock of Washington Gas, which survived the Merger as an indirect, wholly owned subsidiary of AltaGas. In addition, WGL owns all of the shares of common stock of Washington Gas Resources Corporation (Washington Gas Resources) and Hampshire Gas Company (Hampshire). Washington Gas Resources owns all of the shares of common stock of four non-utility subsidiaries that include WGL Energy Services, Inc. (WGL Energy Services), WGL Energy Systems, Inc. (WGL Energy Systems), WGL Midstream, Inc. (WGL Midstream) and WGSW, Inc. (WGSW). Additionally, several subsidiaries of WGL own interests in other entities. Except where the content clearly indicates otherwise, any reference in this report to “Washington Gas,” “we,” “our” , or the “Company,” refers to Washington Gas Light Company. References to “WGL” refer to WGL Holdings, Inc. and all of its subsidiaries. The condensed financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Therefore, certain financial information and note disclosures accompanying annual financial statements prepared in accordance with generally accepted accounting principles in the United States of America (GAAP) are omitted in this interim report. The interim condensed financial statements and accompanying notes should be read in conjunction with the Financial Statements on Form 10-K T . Due to the seasonal nature of our business, the results of operations for the periods presented in this report are not necessarily indicative of actual results for the full years ending December 31, 2019 and 2018. The information presented in this report on Form 10-Q are presented solely for the registrant Washington Gas on a stand-alone basis. The accompanying unaudited condensed financial statements for Washington Gas reflect all normal recurring adjustments that are necessary, in our opinion, to present fairly the results of operations in accordance with GAAP. For a complete description of our significant accounting policies, refer to Note 1- Accounting Policies of the Notes to Consolidated Financial Statements o n Form 10-KT . We include herein certain updates to those policies. Leases Lessee We determine if an arrangement is a lease and the lease classification at inception. For the operating leases in which we are the lessee , a right-of-use (ROU) asset and a lease liability is recognized at the commencement date based on the present value of lease payments over the lease term. We use the rate implicit in the lease to determine the present value of the lease payments when the rate is readily determinable or we use our incremental borrowing rate. Our ROU assets are adjusted for lease incentives, any lease payments made in advance, and initial direct costs incurred . Lease expenses are recognized on a straight-line basis over the lease term. The estimated lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. For our lessee building and certain equipment leases, we do not separate the lease and non-lease components. Variable lease payments are recognized as lease expense when the related facts and circumstances occur, and are dependent on various external factors, including real estate taxes, common area maintenance and usage charges. For our multiple office location leases classified as operating leases, the lease term begins on the date when construction of the leasehold improvements can start and the lessor has allowed us to occupy the respective locations. Leasehold improvement costs are classified as “Property, Plant, and Equipment” on the balance sheet, and are being amortized to “Depreciation and amortization” expense on a straight-line basis over the non-cancelable period of the leases. Lessor We determine if an arrangement is a lease and the lease classification at inception. Lease payments under operating leases are recognized on a straight-line basis over the lease term. For our building leases, we do not separate the lease and non-lease components. Accounting Standards Adopted during the Period and Other Newly Issued Accounting Standards The following tables summarize the Accounting Standards Updates (ASUs) adopted by Washington Gas during the nine months ended September 30, 2019 and other newly issued accounting standards that will be adopted by Washington Gas in the future. ACCOUNTING STANDARDS ADOPTED IN CALENDAR YEAR 2019 Standard Description Date of adoption Effect on the financial statements or other significant matters ASU 2016-02, Leases (Topic 842), ASU 2018-01, Land Easement Practical Expedient for Transition to Topic 842, ASU 2018-11, Targeted Improvements, and ASU 2018-20, Narrow-Scope Improvements for Lessors, including other subsequent ASUs clarifying the guidance. ASU 2016-02 requires recognition of a right-to-use asset and lease liability by lessees on the statement of financial position and disclosure of key information about leasing arrangements. Lessor accounting remains substantially unchanged but the standard modifies what qualifies as a sales-type and direct financing lease and eliminated real-estate specific provisions. The standard requires application using a modified retrospective approach. January 1, 2019 Leases, with terms longer than 12 months, for which Washington Gas is the lessee have been reflected on the balance sheet by recording an increase to non- current assets and an increase to deferred credits net of the current portion that is recorded in current liabilities. Upon adoption, Washington Gas recorded lease liabilities of $58.9 million and a right-of-use asset of $43.2 million, net of lease incentives and prepaid or deferred rent balances of $15.7 million. Washington Gas utilized the transition practical expedients which allow entities to not have to reassess whether an arrangement contains a lease and the lease classification under the provisions of ASC Topic 842, land easements, and not separating out the lease and non-lease components for certain classes of assets. As a result of the transition practical expedients, Washington Gas’ operating leases on transition are consistent with its conclusions under ASC 840. Washington Gas has also elected to present prior comparative information under ASC 840. See Note 3 - Leases for further information and the new required lease disclosures. ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted improvements to Accounting for Hedging Activities and ASU 2018-16, Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes ASU 2017-12 amends the hedge accounting and recognition requirements by expanding an entity’s ability to hedge non-financial and financial risk components and reduce the complexity in fair value hedges of interest rate risk. Additionally, this standard eliminates the requirement to separately measure and disclose the ineffective portion of the hedge with the entire change in the fair value of a hedging instrument to be presented in the same statement of operations line as the hedged item. Early adoption is permitted. ASU 2018-16 adds the OIS rate based on SOFR as a fifth U.S. benchmark interest rate for hedge accounting purposes. This standard should be adopted in conjunction with ASU 2017-12 if not early adopted. January 1, 2019 The guidance will only have an impact on new transactions that are entered into and where hedge accounting is elected. ASU 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (a consensus of the FASB Emerging Issues Task Force) The update aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements to capitalize implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). Capitalized implementation costs should be presented in the statement of financial position as a prepaid expense and amortized over the term of the hosting arrangement, presented in the statements of operations in the same line items as prepayment of fees associated with the hosting arrangement. The updates in this standard may be applied on a prospective or retrospective basis. Early adoption is permitted. January 1, 2019 We early adopted this standard on a prospective basis. The adoption of this ASU did not have a material effect on our financial statements. OTHER NEWLY ISSUED ACCOUNTING STANDARDS Standard Description Required date of adoption Effect on the financial statements or other significant matters ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, including other subsequent ASUs clarifying the guidance. For credit losses on financial instruments, this standard changes the current incurred loss impairment methodology to an expected loss methodology and requires consideration of a broader range of reasonable and supportable information to determine credit loss estimates. Early adoption is permitted. January 1, 2020 We are in the process of evaluating the impact the adoption of this standard will have on our financial statements. ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement This update modifies the disclosure requirements on fair value measurements. Early adoption is permitted. January 1, 2020 It is not expected that the adoption of this standard will have a material effect on our financial statements. ASU 2018-17, Consolidation (Topic 810): Targeted Improvements to Related Party Guidance for Variable Interest Entities This standard provides a private-company scope exception to the VIE guidance for certain entities under common control and clarify that indirect interest held through related parties under common control will be considered on a proportional basis when determining whether fees paid to decision makers and service providers are variable interests. Early adoption is permitted. January 1, 2020 We are in the process of evaluating this new accounting standard but it is expected that the adoption of this standard will not have a material effect on our financial statements. ASU 2019-01, Leases (Topic 842) Codification Improvements This update addresses the determination of the fair value of the underlying asset by lessors that are not manufacturers or dealers, provides guidance for the presentation of the statement of cash flows for sales-type and direct financing leases, and clarifies transition disclosures related to Topic 250. January 1, 2020 We do not anticipate that adoption of this standard will have a material effect on our financial statements. ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans This standard modifies the disclosure requirements related to defined benefit pension and other postretirement plans. Early adoption is permitted. December 31, 2020 We do not anticipate that adoption of this standard will have a material effect on our financial statements.

Revenue from Contracts With Cus

Revenue from Contracts With Customers	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS The Company adopted ASU 2014-09, Revenue from Contracts with Customers (Accounting Standard Codification (ASC) 606) and subsequent ASUs clarifying the guidance on October 1, 2018, using the modified retrospective method of adoption. Under this approach, prior year results are not required to be restated. Adoption of this standard did not change the timing or pattern of revenue recognition and a cumulative-effect adjustment was not recorded upon adoption. As a result, comparative disclosures for operating results for the three and nine months ended September 30, 2019 are not applicable because implementing the new standard did not change the timing or pattern of revenue recognition . The Company recognizes revenue from contracts with customers to depict the transfer of goods or services to customers at an amount it expects to be entitled to in exchange for those goods or services. Washington Gas sells natural gas and distribution services to residential, commercial, industrial and governmental customers through regulated tariff rates approved by regulatory commissions in the jurisdictions where it operates (District of Columbia, Maryland, and Virginia) . Customers are billed monthly based on regular meter readings. Customer billings are based on two main components: (i) a fixed service fee and (ii) a variable fee based on usage. For customers who choose to purchase their natural gas from Washington Gas, the bill will include a usage based charge for the cost of the commodity. Revenue is recognized over time as the natural gas is delivered or as the service is performed. As meter readings are performed on a cycle basis, Washington Gas recognizes accrued revenue for any services rendered to its customers but not billed at month-end. The tariff sales are generally considered daily or “at-will” contracts as customers may cancel their service at any time (subject to notification requirements in the tariff), and revenue generally represents the amount Washington Gas is entitled to invoice. There are certain contracts that have terms of one year or longer. For these contracts, revenue is recognized based on the amount Washington Gas is entitled to bill the customer. Customers have the choice to purchase natural gas from competitive service providers. Washington Gas charges the competitive service providers balancing fees to manage the natural gas transportation imbalances. Where regulations require, Washington Gas issues customers a consolidated bill to include the natural gas supplied by the competitive service providers and distribution of natural gas. Washington Gas recognizes revenue only for distribution services that it has provided to the customer, and the balancing fees for the services provided to the competitive service provider. We disaggregate revenue by type of service. The following table disaggregates revenue for the three and nine months ended September 30, 2019 . Disaggregated Revenue by Type of Service (In millions) Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Revenue from contracts with customers Gas and transportation sales Gas sold and delivered $ 70.7 $ 665.1 Gas delivered for others 33.4 186.8 Other 10.9 34.4 Other revenues 1.4 4.2 Total revenue from contracts with customers $ 116.4 $ 890.5 Other sources of revenue Revenue from alternative revenue programs (a) $ 3.6 $ 14.9 Leasing revenue (b) 0.2 0.5 Other 2.1 8.5 Total revenue from other sources 5.9 23.9 Total Operating Revenue $ 122.3 $ 914.4 (a) Washington Gas has determined that its Revenue Normalization Adjustment (RNA), Weather Normalization Adjustment (WNA), and Conservation and Ratemaking Efficiency (CARE) Ratemaking Adjustment (CRA) billing adjustment mechanisms and accelerated pipe replacement programs are alternative revenue programs and accounted for under ASC Topic 980. (b) Revenue generated from Washington Gas lessor operating leases accounted for under ASC Topic 842, Leases. See Note 3-Leases for further information on leases. Washington Gas accrues unbilled revenues for gas delivered, but not yet billed at the end of each accounting period due to our customer billing cycles. “Unbilled revenues” represent performance obligations that have been satisfied and to which Washington Gas has an unconditional right to payment, except for contract assets related to Washington Gas’ area-wide contract, which requires project acceptance by federal government for the right to payment to occur. As of September 30, 2019 , contract assets of $ 40.5 million have been recorded for financed projects within “Unbilled revenues” on the c ondensed b alance s heets. Washington Gas did not have any contract liabilities at September 30, 2019 . The Company does not have transaction price amounts allocated to future performance obligations. The Company applies the practical expedient available under ASC Topic 606 and does not disclose information about the remaining performance obligations for (i) contracts with an original expected length of one year or less, (ii) contracts for which revenue is recognized at the amount to which the Company has the right to invoice for performance completed, and (iii) contracts with variable consideration that is allocated entirely to a wholly unsatisfied performance obligation or to a wholly unsatisfied promise to transfer a distinct good or service that forms part of a single performance obligation.

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Lessee and Lessor, Operating Leases	LEASES On January 1, 2019, t he Company adopted ASU 2016-02, Leases (ASC 842) and the following subsequent ASUs which amended the guidance: ASU 2018-01, Land Easement Practical Expedient for Transition to Topic 842, ASU 2018-10, Codification Improvements, and ASU 2018-11, Leases Targeted Improvements, and ASU 2018-20, Narrow-Scope Improvements for Lessors. The new leasing standard requires lessees to recognize a ROU asset and lease liability for leases classified as an operating lease. The significant effects of adopting this standard and the qualitative and quantitative disclosures required to enable users of the financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases are included in Note 1- Accounting Policies and below. Adoption of the new standard had a material impact to our balance sheet but did not have a material impact to our statement of operations. On January 1, 2019, the Company recorded ROU assets of $ 43.2 million (net of lease incentives and prepaid or deferred rent of $ 15.7 million ), current lease liability of $ 2.8 million and non - current lease liability of $ 56.1 million related to our operating leases. The Company currently does not have finance leases. We elected to implement the new leasing standard retrospectively at the beginning of the period of adoption through a cumulative-effect adjustment. Under this approach, prior year results are not required to be restated and disclosures associated with prior periods are reported under ASC 840. Lessee Leases The Company elected to use the transition practical expedient which allows an entity not to reassess whether any expired or existing contracts are, or contain, leases; the lease classification for any expired or existing leases; and the initial direct costs for any existing leases. The practical expedient also allows an entity not to reassess whether existing or expired land easements that were not previously accounted for as a lease under Topic 840 was also elected. The Company elected not to separate lease and non-lease components for its building leases and has elected not to record a ROU asset and lease liability for short-term leases. Short-term leases are defined as leases with a term of 12 months or less at the commencement date, including extension options that are reasonably certain of being exercised, and do not include an option to purchase the underlying asset. Short-term lease costs for the period were not material. Washington Gas has operating leases for our corporate headquarters and other corporate offices, communication tower space, and certain office equipment. Our leases have remaining lease terms from 1 to 22 years. Some of the leases include options to extend the lease terms for 1 to 5 years with prior written notice or automatically renew if either party does not provide intent to terminate. The leases generally have options to terminate with notice prior to the end of the lease term based on the contract terms. Refer to Note 13 - Related Party Transactions for discussion of leases with associated companies. The following table provides our expected operating lease payments as of September 30, 2019 . Maturity of Operating Lease Liabilities (In millions) September 30, 2019 2019 $ 1.3 2020 5.9 2021 5.5 2022 5.5 2023 5.5 Thereafter 52.1 Total lease payments $ 75.8 Less: Interest (15.5 ) Present Value of Lease Liabilities $ 60.3 The following table provides supplemental cash flow information related to operating leases for the three and nine months ended September 30, 2019 . Supplemental Cash Flow Information Related to Operating Leases ($ in millions) Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Cash paid for amounts included in the lease liabilities in the operating cash flows $ 0.5 $ 1.5 Operating lease cost (including variable lease costs of $0.5 million and $1.5 million for the three and nine months ended September 30, 2019, respectively) $ 1.8 $ 5.4 Right-of-use assets obtained in exchange for new operating lease liabilities $ 0.4 $ 1.5 At September 30, 2019, the weighted average remaining lease term for operating leases was 13.5 years , and the weighted average discount rate was 3.32% . Lessor Leases The Company also has lessor leases for land, office space and communication tower space that are classified as operating leases. The accounting for these operating leases remained unchanged upon the adoption of ASC 842. Washington Gas has elected not to separate the lease and non-lease components for its building leases. Our leases have remaining lease terms ranging from less than a year to 82 years. Some of the leases include options to extend the lease terms for 1 to 5 years with prior written notice or automatically renew if the lessee does not provide intent not to renew. The leases generally have options to terminate the leases with notice prior to the end of the lease term based on the contract terms. The lease agreements do not contain material residual value guarantees. The following table summarizes the future operating lease payments to be received associated with these leases. Maturity of Operating Lease Payments (a) (In millions) September 30, 2019 2019 $ 0.2 2020 0.7 2021 0.6 2022 0.6 2023 0.6 Thereafter 58.3 Total lease payments $ 61.0 (a) The payments are presented on an undiscounted basis The property, plant and equipment associated with these leases are not material. For information on the lease income recognized during the period, see the Disaggregated Revenue by Type of Service table in Note 2 - Revenue f rom Contracts with Customers. During the three and nine months ended September 30, 2019 , Washington Gas did not record any impairments related to our leased assets.

Accounts Payable and Other Accr

Accounts Payable and Other Accrued Liabilities	9 Months Ended
	Sep. 30, 2019
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable and Other Accrued Liabilities	ACCOUNTS PAYABLE AND OTHER ACCRUED LIABILITIES The table below provides details for the amounts included in “Accounts payable and other accrued liabilities” on the condensed balance sheet s . (In millions) September 30, 2019 December 31, 2018 Accounts payable—trade $ 139.4 $ 228.9 Employee benefits and payroll accruals 16.5 28.0 Other accrued liabilities 26.9 31.5 Total $ 182.8 $ 288.4

Short-Term Debt

Short-Term Debt	9 Months Ended
	Sep. 30, 2019
Short-term Debt [Abstract]
Short-Term Debt	SHORT-TER M DEBT Washington Gas satisfies its short-term financing requirements through the sale of commercial paper, financing arrangements with third-party lenders, or bank borrowings. Due to the seasonal nature of our operations, short-term financing requirements can vary significantly during the year. Revolving credit agreements are maintained to support outstanding commercial paper and to permit short-term borrowing flexibility. The policy of Washington Gas is to maintain bank credit facilities in amounts equal to or greater than the expected maximum commercial paper position. The following is a summary of committed credit available at September 30, 2019 and December 31, 2018 . Committed Credit Available ($ in millions) September 30, 2019 December 31, 2018 Committed credit agreements Unsecured revolving credit facility $ 450.0 $ 350.0 Less: Commercial paper outstanding (117.0 ) (296.0 ) Net committed credit available $ 333.0 $ 54.0 Weighted average interest rate 2.31 % 2.93 % At September 30, 2019 and December 31, 2018 , there were no outstanding bank loans from Washington Gas’ revolving credit facilities. On July 19, 2019, Washington Gas entered into a n amended and restated senior unsecured revolving credit facility with a term of five years, plus two one-year extension options, available with the bank group’s approval (Credit Facility). The Credit Facility amended and restated Washington Gas’ prior $ 350 million credit facility and permits Washington Gas to borrow up to $ 450 million with an option to increase the facility by an additional $ 100 million , with the bank group’s approval, for a total potential maximum borrowing of $ 550 million . Washington Gas incurs credit facility fees, which in some cases are based on the long-term debt ratings of Washington Gas. In the event that the long-term debt ratings are downgraded below certain levels, Washington Gas would be required to pay higher fees. There are five different levels of fees. Under the terms of the credit facilities, the lowest level facility fee is 0.06% and the highest is 0.175% . The interest rate of loans made under the credit facilities will be a fluctuating rate per annum that will be set using certain parameters at the time each loan is made. Project Financing Washington Gas previously obtained third-party project financing on behalf of the federal government to provide funds for the construction of certain energy management services projects entered under Washington Gas’ area-wide contract. Washington Gas recorded a project financing obligation in “Notes payable and project financing” on the balance sheet. As the construction work was performed by WGL Energy Systems, Washington Gas established a contract asset in “Unbilled revenue” representing the government’s obligation to remit principal and interest, and recorded a “Payable to associated company” to WGL Energy Systems for the construction work performed for the same amount. WGL Energy Systems now directly obtains third-party project financing for its energy management services projects. As work is performed, Washington Gas establishes a contract asset in “Unbilled revenue” representing the government’s obligation to remit principal and interest and records a “Payable to associated company” to WGL Energy Systems for the construction work performed for the same amount. As of September 30, 2019 , Washington Gas recorded $ 40.5 million of contract assets in “Unbilled revenues” and a $ 40.5 million payable to WGL Energy Systems in “Payables to associated companies,” respectively, for energy management services projects financed by WGL Energy Systems that were not complete. There was no project financing obligation on Washington Gas’ balance sheet as of September 30, 2019 . As of December 31, 2018 , Washington Gas recorded $ 85.3 million of contract assets in “Unbilled revenues,” $ 15.5 million in a corresponding short-term financing to third-party lenders in “Notes payable and project financing,” and $69.7 million accounts payable to WGL Energy Systems in “Payables to associated companies” for energy management services projects that were not complete. In October 2018, WGL Energy Systems repaid $53.0 million drawn by Washington Gas from a third-party lender for a specific project for which the lender demanded repayment due to delays in achieving final acceptance from the federal government agency customer. The $ 53.0 million was included in “Payables to associated companies” on Washington Gas’ balance sheet as of December 31, 2018. On January 16, 2019, the federal government agency customer provided notification of final acceptance as of December 14, 2018. In February 2019, WGL sold the receivables, and accordingly, Washington Gas reversed the associated amount in “Payables to associated companies” and “Unbilled revenue” on its balance sheet. Washington Gas did not record a corresponding reserve for bad debts related to these contract assets at September 30, 2019 and December 31, 2018 , based on our previous collection experience with receivables that have been financed for government agencies with minimal credit risk.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Long-Term Debt	LONG-TERM DEBT Unsecured Notes Washington Gas issues long-term debt in the form of medium-term notes (MTNs), unsecured long-term notes and private placement notes, all of which contain individual terms regarding interest rates, maturities and call or put options. Each of these note types can have maturity dates of one or more years from the date of issuance. The following table shows the outstanding notes as of September 30, 2019 and December 31, 2018 . Long-Term Debt Outstanding ($ in millions) September 30, 2019 December 31, 2018 Total Long-Term Debt (a) $ 1,396.0 $ 1,096.0 Unamortized discount (4.3 ) (2.9 ) Unamortized debt expense (10.6 ) (8.1 ) Less—current maturities 50.0 50.0 Total Long-Term Debt $ 1,331.1 $ 1,035.0 Weighted average interest rate (b) 4.53 % 4.77 % (a) Includes MTNs and private placement notes. The amount represents face value of long-term debt including current maturities. (b) Weighted average interest rate is for the long-term debt including current maturities. On September 13, 2019, Washington Gas issued medium-term notes with an aggregate princip al amount of $ 300 million and 3.65% fixed interest rate that are due in September 2049. The interest will be paid semi-annually in March and September of each year. The notes have a make-whole call provision at a U.S. T reasury rate plus 25 b asis p oint s prior to March 15, 2049, and then are callable at par after March 15, 2049. There w as no issuance of long-term debt for the nine months ended September 30, 2018 . There were no retirements of long-term debt for the nine months ended September 30, 2019 or 2018 .

Components of Total Equity

Components of Total Equity	9 Months Ended
	Sep. 30, 2019
Components of Total Equity [Abstract]
Components of Total Equity	COMPONENTS OF TOTAL EQUITY The tables below reflect the components of “Total equity” for the three and nine months ended September 30, 2019 and 2018 . . Components of Total Equity (In thousands, except shares) Common Stock Paid-In Capital Retained Earnings Accumulated Other Comprehensive Income (Loss), Net of Taxes Total Shares Amount Three Months Ended September 30, 2019 Balance at June 30, 2019 46,479,536 46,479 979,273 585,193 (6,141 ) $ 1,604,804 Net loss — — — (65,799 ) — $ (65,799 ) Other comprehensive income (loss) — — — — 942 $ 942 Dividends declared: Common stock — — — — — $ — Preferred stock — — — — — $ — Balance at September 30, 2019 46,479,536 46,479 979,273 519,394 (5,199 ) 1,539,947 Three Months Ended September 30, 2018 Balance at June 30, 2018 46,479,536 46,479 585,562 723,749 (3,959 ) 1,351,831 Net loss — — — (181,153 ) — $ (181,153 ) Other comprehensive income (loss) — — — — 3,613 $ 3,613 Stock-based compensation (a) — — (9,017 ) — — $ (9,017 ) Capital contribution from parent — 302,728 $ 302,728 ASU 2018-02 adoption impact (b) 1,484 (1,484 ) — Dividends declared: Common stock — — — (24,908 ) — $ (24,908 ) Preferred stock — — — (330 ) — $ (330 ) Balance at September 30, 2018 46,479,536 46,479 879,273 518,842 (1,830 ) 1,442,764 Nine Months Ended September 30, 2019 Balance at December 31, 2018 46,479,536 46,479 979,273 543,448 (6,627 ) 1,562,573 Net income — — — 26,606 — 26,606 Other comprehensive income (loss) — — — — 1,428 1,428 Dividends declared: Common stock — — — (50,000 ) — (50,000 ) Preferred stock — — — (660 ) — (660 ) Balance at September 30, 2019 46,479,536 46,479 979,273 519,394 (5,199 ) 1,539,947 Nine Months Ended September 30, 2018 Balance at December 31, 2017 46,479,536 46,479 583,185 670,580 (4,330 ) $ 1,295,914 Net income — — — (84,568 ) — $ (84,568 ) Other comprehensive income (loss) — — — — 3,984 $ 3,984 Stock-based compensation (a) — — (6,640 ) — — $ (6,640 ) Capital contribution from parent — — 302,728 — — $ 302,728 ASU 2018-02 adoption impact (b) $ 1,484 $ (1,484 ) — Dividends declared: Common stock — — — (67,664 ) — $ (67,664 ) Preferred stock — — — (990 ) — $ (990 ) Balance at September 30, 2018 46,479,536 46,479 879,273 518,842 (1,830 ) 1,442,764 (a) Stock-based compensation is based on the stock awards of WGL that are allocated to Washington Gas Light Company for its pro-rata share and includes implementation of ASU 2016-09. (b) Amount related to the adoption of ASU 2018-02. Washington Gas reclassified a credit of $ 1.5 million from AOCI to retained earnings at September 30, 2018.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Washington Gas is included in the ASUS consolidated income tax returns beginning with the period from July 7, 2018 to December 31, 2018. We have established a new tax sharing policy with ASUS. During the three and nine months ended September 30, 2019 , Washington Gas did not make or receive any payments to or from its associated companies related to the legacy WGL tax sharing agreement or the new tax sharing agreement. Amounts of Interest and Penalties Recognized Washington Gas recognizes any accrued interest associated with uncertain tax positions in interest expense and recognizes any accrued penalties associated with uncertain tax positions in other expenses in the statements of operations. During the three and nine months ended September 30, 2019 and 2018, there were no accrued interest expenses or penalties associated with uncertain tax positions.

Pension and Other Post-Retireme

Pension and Other Post-Retirement Benefit Plans	9 Months Ended
	Sep. 30, 2019
Retirement Benefits [Abstract]
Pension and Other Post-Retirement Benefit Plans	PENSION AND OTHER POST-RETIREMENT BENEFIT PLAN S The following table shows the components of net periodic benefit costs (income) recognized in our financial statements during the three and nine months ended September 30, 2019 and 2018 : Components of Net Periodic Benefit Costs (Income) Three Months Ended September 30, 2019 2018 (In millions) Pension Benefits Health and Life Benefits Pension Benefits Health and Life Benefits Service cost $ 3.0 $ 1.3 $ 3.7 $ 1.3 Interest cost 10.2 3.0 9.9 2.9 Expected return on plan assets (10.7 ) (6.1 ) (10.6 ) (5.9 ) Recognized prior service cost (credit) 0.1 (3.9 ) 0.1 (4.4 ) Recognized actuarial loss 1.3 — 3.9 — Net periodic benefit cost (income) 3.9 (5.7 ) 7.0 (6.1 ) Allocation to affiliates (0.4 ) 0.5 (0.9 ) 0.7 Adjusted net periodic benefit cost (income) 3.5 (5.2 ) 6.1 (5.4 ) Amount allocated to construction projects (b) (0.4 ) (0.2 ) (1.0 ) 0.8 Amount deferred as regulatory asset (liability)-net allocations (c) — — 1.7 — Amount charged (credited) to expense $ 3.1 $ (5.4 ) $ 6.8 $ (4.6 ) Nine Months Ended September 30, 2019 2018 (In millions) Pension Benefits Health and Life Benefits Pension Benefits Health and Life Benefits Service cost $ 9.1 $ 3.8 $ 11.1 $ 3.9 Interest cost 30.7 9.0 29.7 8.7 Expected return on plan assets (32.1 ) (18.3 ) (31.7 ) (17.7 ) Recognized prior service cost (credit) 0.3 (11.7 ) 0.3 (13.2 ) Recognized actuarial loss 4.0 — 11.7 — Settlement charge (a) 4.3 — — — Net periodic benefit cost (income) 16.3 (17.2 ) 21.1 (18.3 ) Allocation to affiliates (1.3 ) 1.8 (2.6 ) 2.1 Adjusted net periodic benefit cost (income) 15.0 (15.4 ) 18.5 (16.2 ) Amount allocated to construction projects (b) (1.2 ) (0.6 ) (3.6 ) 2.9 Amount deferred as regulatory asset (liability)-net allocations (c) 0.7 — 4.7 — Amount charged (credited) to expense $ 14.5 $ (16.0 ) $ 19.6 $ (13.3 ) (a)Amount relates to a one - time partial settlement charge associated with a lump sum payment to Washington Gas’ defined benefit supplemental executive retirement plan (DB SERP) that was paid in the first quarter of 2019. (b)On October 1, 2018, Washington Gas adopted ASU 2017-07. As a result, only the service cost component of net periodic benefit costs (income) is eligible for capitalization. (c)Amount represents the amortization of previously unrecovered costs of the applicable pension benefits or the health and life benefits as approved in the District of Columbia through 2019. At September 30, 2019 and December 31, 2018 , the rabbi trust balance associated with the DB SERP and non-funded defined benefit restoration plan (DB restoration) plans was $ 43.8 million and $ 60.8 million , respectively. $ 4.2 million and $ 20.2 million was recorded in “Current Assets-Other” and $ 39.6 million and $ 40.6 million was recorded in “Deferred Charges and Other Assets - Other” respectively, along with other rabbi trust balances. On October 1, 2018, Washington Gas adopted ASU 2017-07. This standard requires entities to report the service cost component in the same financial statement line item as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are to be presented separately from service cost and outside of operating income. In addition, only the service cost component of net benefit cost is eligible for capitalization. Changes to the presentation of service costs and other components of net benefit cost were applied retrospectively. As a result of the retrospective adoption, we reclassified $ 2.8 million and $ 8.4 million of net periodic benefit income from “Operation and maintenance” expense to “Other income (expense)-net” on the statement of operations for the three and nine months ended September 30, 2018 . Changes in capitalization practices were implemented prospectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Contractual Obligations Washington Gas has certain contractual obligations incurred in the normal course of business that require fixed and determinable payments in the future. These commitments include long-term debt, lease obligations, unconditional purchase obligations for pipeline capacity, transportation and storage services, and our commitments related to the business process outsourcing program. For our contractual obligations, refer to Note 12 - Commitments and Contingencies to the Financial Statements in Form 10-K T for the Transition Period from October 1, 2018 to December 31, 2018. Refer to Note 6- Long-term Debt of the Notes to Condensed Financial Statements for long term debt issued during the current period. There were no other significant changes to contractual obligations that are out of the normal course of business during the nine months ended September 30, 2019 . Silver Spring, Maryland Incident On April 23, 2019, the National Transportation and Safety Board (NTSB) held a hearing during which it found, among other things, that the probable cause of the August 10, 2016, explosion and fire at an apartment complex on Arliss Street in Silver Spring, Maryland “was the failure of an indoor mercury service regulator with an unconnected vent line that allowed natural gas into the meter room where it accumulated and ignited from an unknown ignition source. Contributing to the accident was the location of the mercury service regulators where leak detection by odor was not readily available.” Washington Gas disagrees with the NTSB’s probable cause findings. Following this hearing, on June 10, 2019, the NTSB issued an accident report. In connection with the incident, a total of 37 civil actions related to the incident have been filed and are pending against WGL and Washington Gas in the Circuit Court for Montgomery County, Maryland. All cases have been consolidated for discovery purposes. All of these suits seek unspecified damages for personal injury and/or property damage. A trial date for eight bellwether civil actions has been scheduled for December 2, 2019. In addition, two suits were recently filed related to the incident, one each in the Superior Court for the District of Columbia and one in the Circuit Court of Montgomery County, Maryland. At this stage of the litigation, the outcome is not yet determinable and management is unable to make an estimate of any potential loss or range of potential losses that are reasonably possible of occurring. As a result, management has only recorded a reserve for a few of the actions for which a settlement offer was made. Washington Gas maintains excess liability insurance coverage from highly-rated insurers, subject to a nominal self-insured retention. Washington Gas believes that this coverage will be sufficient to cover any significant liability that may result from this incident. Regulatory Contingencies Certain legal and administrative proceedings incidental to our business, including regulatory contingencies, involve Washington Gas. In our opinion, we have recorded an adequate provision for probable losses or refunds to customers for regulatory contingencies related to these proceedings. Merger Commitments In connection with the Merger, AltaGas and WGL made commitments related to the terms of the Public Service Commission of the District of Columbia (PSC of DC) settlement agreement and the conditions of approval from the Public Service Commission of Maryland (PSC of MD) and the State Corporation Commission of Virginia ( SCC of VA). Among other things, these commitments include rate credits distributable to both residential and non-residential customers, gas expansion and other programs, various public interest commitments, and safety programs. The cumulative amount expensed as of September 30, 2019 was $ 136.6 million , of which $ 118.7 million has been paid, including $ 1.1 million and $7.6 million paid in the three a nd nine months ended September 30, 2019 , respectively. In March 2019, the PSC of MD directed that the $ 3.9 million Most Favored Nation adjustment, originally recorded as a commitment expense, should be used to offset future rates under Washington Gas’ natural gas expansion program in Maryland. As a result, Washington Gas reversed the commitment expense in the first quarter of 2019. Further, there are additional regulatory commitments that will be recorded when the costs are incurred in the future, including the hiring of damage prevention trainers in each jurisdiction for a total amount of $ 2.4 million over 5 years; investing up to $ 70.0 million over a 10 year period to further extend natural gas service; and spending $ 7.5 million for leak mitigation within three years of the Merger close . Application for Approval of Reduction of Distribution Rates On January 12, 2018, Washington Gas filed applications to reduce customer rates in Maryland, Virginia, and the District of Columbia to reflect the impact of the Tax Act, including both the impact of the re-measurement of deferred tax assets and liabilities and reduction of the federal tax rate to 21%. Washington Gas began tracking the impact of the Tax Act on revenue requirements beginning January 1, 2018, recording all impacts to regulatory assets and liabilities. In Maryland and the District of Columbia, rates have been adjusted for the impact of the Tax Act. In Virginia, the SCC of VA dismissed the application on March 15, 2018. Washington Gas filed a new general rate case on July 31, 2018 incorporating the effects of the Tax Act. On September 16, 2019, the Hearing Examiner (HE) issued a report to the SCC of VA recommending the Company increase its liability balance for the Tax Act to $35.4 million and for it t o be refunded to customers in a one - time sur-credit. Accordingly, a t September 30, 2019, Washington G as recorded an $18.9 million adjustment to the liability and will refund the credits after the SCC of VA’s final order is issued. See the discussion below f or a further discussion of the HE ’s r eport. Virginia Jurisdiction Virginia Rate Case. On July 31, 2018, Washington Gas filed an application with the SCC of VA to increase its base rates for natural gas service by $ 37.6 million , which includes $ 14.7 million of revenue associated with natural gas pipeline replacement initiatives previously approved by the SCC of VA and paid by customers through a monthly rider. Additionally, the requested revenue increase incorporated the effects of The Tax Act. Interim rates became effective, subject to refund, for usage in the January 2019 billing cycle. On April 12, 2019, Washington Gas filed rebuttal testimony and revised its original return on equity down from 10.6% to 10.3% and its overall rate of return down from 7.94% to 7.81% . Evidentiary hearings were held on April 30 and May 1, 2019. Post hearing briefs were filed on July 3, 2019. On September 16, 2019, the HE issued a report to the SCC of VA which recommended among other things: (i) no increase in base rate revenue; (ii) a return on equity of 9.2% compared to the current authorized return on equity rate of 9.5% ; (iii) unprotected plant-related and non-plant-related excess deferred income tax should be amortized as a reduction in rates over 5 years compared to amortizing using Average Rate Assumption Method (ARAM) and over 15 years, respectively; (iv) refund $5.6 million to customers for tax savings related to the October 2017 to December 2017 period as part of the Tax Act savings owed to customer, and (v) write off a $7.1 million regulatory asset related to flowthrough income taxes that the company had recovered previously flowed through depreciation income tax deductions via the SAVE rider. For the nine months ended September 30, 2019, Washington Gas made the following pre-tax adjustments based on the HE’s recommendations: (i ) reduced “Operating revenues-Utility” by $7.6 million to accrue additional amounts of liability subject to refund; (ii) reduced “Operating revenues-Utility” by $13.3 million associated with the revised amortization of the Tax Act liability; and (iii) wrote off $2.0 million in “Regulatory Assets - Other” and charged to “Operation and maintenance” expense. Additionally, the Company reduced income tax expense by $11.8 million related to the amortization of excess deferred income tax, and recorded a $5.5 million after-tax impairment of a tax regulatory asset related to flowthrough income taxes. Reply comments on the HE’s report were filed by Washington Gas on October 21, 2019. Washington Gas filed reply comments challenging eleven recommendations contained in the HE’s report, including some of the items highlighted above, where the bases for the findings either disregard or are contrary to the substantial evidentiary record. Maryland Jurisdiction Maryland Show-Cause Order. On September 5, 2019, the PSC of MD ordered the Company, within 30 days, to (i) provide a detailed response to the NTSB’s probable cause findings, and (ii) provide evidence regarding the status of a 2003 mercury regulator replacement program, and if the program was not completed, to show cause why the Commission should not impose a civil penalty on the Company. On September 16, 2019, the PSC of MD granted the Company a 14-day extension to file its Response to the Show-Cause Order. On October 18, 2019, the Company filed its Response to the Show-Cause Order, (i) providing a detailed response to the NTSB’s probable cause findings and (ii) providing evidence regarding the status of a 2003 mercury regulator replacement program and why the Commission should not impose a civil penalty on the Company. The PSC of MD has not adopted a procedural schedule with respect to this matter but has indicated that it will schedule one public hearing near the apartment complex at Arliss Street. Given the early stage of the Show-Cause proceeding, the outcome is not yet determinable and management is unable to predict the likelihood of a civil penalty, or make an estimate of any potential civil penalty or range of potential civil penalty. Financial Guarantees At September 30, 2019 and December 31, 2018, there were no guarantees to external parties. Antero Contract In June 2019, a jury trial was held in the County Court for Denver, Colorado to consider a contractual dispute relating to gas pricing between Washington Gas and WGL Midstream (together, the Companies) and Antero Resources Corporation (Antero). Following the trial, the jury returned a verdict in favor of Antero for $95.9 million , of which $11.2 million was against Washington Gas, and $84.7 million against WGL Midstream. Following the official entry of the judgment, the Company filed an appeal on August 16, 2019. As a result of this verdict, it was determined that a loss contingency is probable and Washington Gas has recorded an estimated liability of $ 11.2 million in “Accounts payable and accrued liabilities” on the balance sheet as of September 30, 2019, of which $ 2.6 million had already been recorded in a prior period. Washington Gas has also recorded a receivable from our trading partner of $ 1.3 million net in “Accounts payable and accrued liabilities” and sharing with customers as the contract relates to asset optimization of $ 4.5 million in “Deferred charges and other assets - Gas costs”. In addition, Washington Gas has recorded an accrual for estimated court fees of $ 0.1 million , and an accrual of interest expense associated with the liability. For the nine months ending September 30, 2019, the net pre-tax loss recorded as a result of the verdict was $ 3.0 million in “Utility cost of gas” on Washington Gas’ statements of operations. Environmental Matters We are subject to federal, state and local laws and regulations related to environmental matters. These laws and regulations may require expenditures over a long time frame to control environmental effects. Almost all of the environmental liabilities we have recorded are for costs expected to be incurred to remediate sites where we or a predecessor affiliate operated manufactured gas plants (MGPs). Washington Gas has identified up to ten sites where it or its predecessors may have operated MGPs. Washington Gas last used any such plant in 1984. In connection with these operations, we are aware that coal tar and certain other by-products of the gas manufacturing process are present at or near some former sites and may be present at others. At September 30, 2019 and December 31, 2018 , Washington Gas reported a liability of $ 10.7 million and $ 11.3 million on an undiscounted basis related to future environmental response costs. These estimates principally include the minimum liabilities associated with a range of environmental response costs expected to be incurred. At September 30, 2019 and December 31, 2018 , Washington Gas estimated the maximum liability associated with all of its sites to be approximately $35.8 million and $ 29.4 million , respectively. The estimates were determined by Washington Gas’ environmental experts, based on experience in remediating MGP sites and advice from legal counsel and environmental consultants. The variation between the recorded and estimated maximum liability primarily results from differences in the number of years that will be required to perform environmental response processes and the extent of remediation that may be required. Washington Gas is currently remediating its East Station property, located in Washington D.C. adjacent to the Anacostia River, including ground water pump and treat, tar recovery, soil encapsulation and other treatment. Under a 2012 consent decree with the District of Columbia and the federal government, Washington Gas is also conducting a remedial investigation and feasibility study on an adjacent property owned by the District of Columbia. Additional remediation may be required at this property. In addition, at another adjoining property known as the “Boat Club Property,” located to the east of the property owned by the District of Columbia, Washington Gas agreed to perform a site investigation and report the findings pursuant to oversight by the District of Columbia Department of Energy and Environment (DOEE). This property was subject to a July 12, 2019, Administrative Order from the DOEE. This Administrative Order has been withdrawn. A consent order is being negotiated. Washington Gas received a letter in February 2016 from the DOEE and National Park Service regarding the Anacostia River Sediment Project, indicating that the District of Columbia is conducting a separate remedial investigation and feasibility study of the river to determine if and what cleanup measures may be required and to prepare a natural resource damage assessment. The sediment project draft remedial investigation report issued on March 30, 2018 identifies East Station as one of seventeen potential environmental cleanup sites. We are not able to estimate the total amount of potential damages or timing associated with the District of Columbia’s environmental investigation on the Anacostia River at this time. While an allocation method has not been established, Washington Gas has accrued an amount for study costs based on a potential range of estimates. Regulatory orders issued by the PSC of MD allow Washington Gas to recover the costs associated with the sites applicable to Maryland over the period ending in 2025. Rate orders issued by the PSC of DC allow Washington Gas a three-year recovery of prudently incurred environmental response costs and allow Washington Gas to defer additional costs incurred between rate cases. Regulatory orders from the SCC of VA have generally allowed the recovery of prudent environmental remediation costs to the extent they were included in the underlying financial data supporting an application for rate change. At September 30, 2019 and December 31, 2018 , Washington Gas reported a regulatory asset of $ 6.3 million and $ 5.8 million for the portion of environmental response costs that are expected to be recoverable in future rates.

Derivative and Weather Related

Derivative and Weather Related Instruments	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative and Weather-Related Instruments	DERIVATIVES Derivative Instruments Washington Gas enters into contracts that qualify as derivative instruments and are accounted for under ASC Topic 815. These derivative instruments are recorded at fair value on our balance sheet and Washington Gas does not currently designate any derivatives as hedges under ASC Topic 815. Washington Gas’ derivative instruments relate to: (i) Washington Gas’ asset optimization program; (ii) managing price risk associated with the purchase of gas to serve utility customers and (iii) managing interest rate risk. Asset Optimization. Washington Gas optimizes the value of its long-term natural gas transportation and storage capacity resources during periods when these resources are not being used to physically serve utility customers. Specifically, Washington Gas utilizes its transportation capacity assets to benefit from favorable natural gas prices between different geographic locations and utilizes its storage capacity assets to benefit from favorable natural gas prices between different time periods. As part of this asset optimization program, Washington Gas enters into physical and financial derivative transactions in the form of forward, futures and option contracts with the primary objective of securing operating margins that Washington Gas will ultimately realize. The derivative transactions entered into under this program are subject to mark-to-market accounting treatment under ASC Topic 820. Regulatory sharing mechanisms provide for the annual realized profit from these transactions to be shared between Washington Gas’ shareholders and customers; therefore, changes in fair value are recorded through earnings, or as regulatory assets or liabilities to the extent that it is probable that realized gains and losses associated with these derivative transactions will be included in the rates charged to customers when they are realized. Unrealized gains and losses recorded to earnings may cause significant period-to-period volatility; this volatility does not change the operating margins that Washington Gas expects to ultimately realize from these transactions through the use of its storage and transportation capacity resources. All physically and financially settled contracts under our asset optimization program are reported on a net basis in the statements of operations in “Utility cost of gas.” Total net margins recorded to “Utility cost of gas” after sharing and management fees associated with all asset optimization transactions for the three months ended September 30, 2019 was a net loss of $1.2 million including an unrealized loss of $6.5 million . During the three months ended September 30, 2018 , we recorded a net gain of $7.7 million including an unrealized gain of $3.3 million . Total net margins recorded to “Utility cost of gas” after sharing and management fees associated with all asset optimization transactions for the nine months ended September 30, 2019 was a net gain of $8.3 million including an unrealized gain of $0.1 million and a $3.0 million loss related to the Antero Contract. During the nine months ended September 30, 2018 , we recorded a net gain of $28.5 million including an unrealized gain of $11.8 million . Refer to Note 10- Commitments and Contingencies for further discussion of the Antero Contract. Managing Price Risk. To manage price risk associated with acquiring natural gas supply for utility customers, Washington Gas enters into physical and financial derivative transactions in the form of forward, option and other contracts, as authorized by its regulators. Any gains and losses associated with these derivatives are recorded as regulatory liabilities or assets, respectively, to reflect the rate treatment for these economic hedging activities. Managing Interest-Rate Risk. Washington Gas may utilize derivative instruments that are designed to minimize the risk of interest-rate volatility associated with planned issuances of debt securities. Any gains and losses associated with these types of derivatives are recorded as regulatory liabilities or assets, respectively, and amortized in accordance with regulatory requirements, typically over the life of the related debt. As of September 30, 2019 and December 31, 2018 , Washington Gas does not have any interest rate swaps in derivatives. Operations The following table presents absolute notional amounts of our derivative instruments as of September 30, 2019 and December 31, 2018 . Absolute Notional Amounts of Open Positions on Derivative Instruments Notional Amounts September 30, 2019 December 31, 2018 Natural Gas (In millions of therms) Asset optimization & trading 11,951.0 13,051.0 Other risk-management activities 950.0 1,072.0 The following table presents the balance sheet classification for all derivative instruments as of September 30, 2019 and December 31, 2018 . Balance Sheet Classification of Derivative Instruments (b) (in millions) Gross Gross Total (a) As of September 30, 2019 Current Assets—Derivatives $ 3.0 $ 0.6 $ 3.6 Deferred Charges and Other Assets—Derivatives 8.5 — 8.5 Current Liabilities—Derivatives 0.1 (12.9 ) (12.8 ) Deferred Credits—Derivatives — (105.1 ) (105.1 ) Total $ 11.6 $ (117.4 ) $ (105.8 ) As of December 31, 2018 Current Assets—Derivatives $ 25.7 $ (6.2 ) $ 19.5 Deferred Charges and Other Assets—Derivatives 11.3 — 11.3 Current Liabilities—Derivatives 1.1 (21.4 ) (20.3 ) Deferred Credits—Derivatives — (116.8 ) (116.8 ) Total $ 38.1 $ (144.4 ) $ (106.3 ) (a) Washington Gas has elected to offset the fair value of recognized derivative instruments against the right to reclaim or the obligation to return collateral for derivative instruments executed under the same master netting arrangement in accordance with ASC Topic 815. All recognized derivative contracts and associated financial collateral subject to a master netting arrangement or similar that is eligible for offset under ASC Topic 815 have been presented net in the balance sheet. (b) Washington Gas did not have derivative instruments outstanding that were designated as hedging instruments at September 30, 2019 or December 31, 2018 . The following table presents all gains and losses associated with derivative instruments for the three and nine months ended September 30, 2019 and 2018 . Gains and (Losses) on Derivative Instruments (In millions) Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Recorded to income Utility cost of gas (5.8 ) 2.0 (0.1 ) 0.5 Recorded to regulatory assets Gas costs (9.6 ) 3.7 4.8 (1.8 ) Total $ (15.4 ) $ 5.7 $ 4.7 $ (1.3 ) Collateral Washington Gas utilizes standardized master netting agreements, which facilitate the netting of cash flows into a single net exposure for a given counterparty. As part of these master netting agreements, cash, letters of credit and parent company guarantees may be required to be posted or obtained from counterparties in order to mitigate credit risk related to both derivatives and non-derivative positions. Under Washington Gas’ offsetting policy, collateral balances are offset against the related counterparties’ derivative positions to the extent the application would not result in the over-collateralization of those derivative positions on the balance sheet. Any collateral posted that is not offset against derivative assets and liabilities is included in “Other prepayments” in the condensed balance sheet. Collateral received and not offset against derivative assets and liabilities is included in “Customer deposits and advance payments” in the accompanying condensed balance sheet. At September 30, 2019 and December 31, 2018 , Washington Gas had $3.3 million and $7.4 million , respectively, in collateral deposits posted with counterparties that are not offset against derivative asset and liabilities. At September 30, 2019 and December 31, 2018 , Washington Gas had $0.1 million and $0.2 million , respectively, cash collateral held representing an obligation, and are not offset against derivative asset and liabilities. Certain derivative instruments of Washington Gas contain contract provisions that require collateral to be posted if the credit rating of Washington Gas falls below certain levels or if counterparty exposure to Washington Gas exceeds a certain level (credit-related contingent features) . At September 30, 2019 and December 31, 2018 , Washington Gas was not required to post collateral related to a derivative liability that contained a credit-related contingent feature. The following table shows the aggregate fair value of all derivative instruments with credit-related contingent features that are in a liability position, as well as the maximum amount of collateral that would be required if the most intrusive credit-risk-related contingent features underlying these agreements were triggered on September 30, 2019 and December 31, 2018 , respectively. Potential Collateral Requirements for Derivative Liabilities with Credit-Risk-Contingent Features (In millions) September 30, 2019 December 31, 2018 Derivative liabilities with credit-risk-contingent features $ — $ 1.1 Maximum potential collateral requirements — 1.0 We do not enter into derivative contracts for speculative purposes. Concentration of Credit Risk We are exposed to credit risk from derivative instruments with wholesale counterparties, which is represented by the fair value of these instruments at the reporting date. We actively monitor and work to minimize counterparty concentration risk through various practices. At September 30, 2019 , two counterparties each represented over 10% of Washington Gas’ credit exposure to wholesale derivative counterparties for a total credit risk of $14.6 million .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS We measure the fair value of our financial assets and liabilities using a combination of the income and market approaches in accordance with ASC Topic 820. These financial assets and liabilities primarily consist of derivatives recorded on our balance sheet under ASC Topic 815 and short-term investments, commercial paper and long-term debt outstanding required to be disclosed at fair value. Under ASC Topic 820, fair value is defined as the exit price, representing the amount that would be received in the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. To value our financial instruments, we use market data or assumptions that market participants would use, including assumptions about credit risk (both our own credit risk and the counterparty’s credit risk) and the risks inherent in the inputs to valuation. We enter into derivative contracts in the futures and over-the-counter (OTC) wholesale and retail markets. These markets are the principal markets for the respective wholesale and retail contracts. Our relevant market participants are our existing counterparties and others who have participated in energy transactions at our delivery points. These participants have access to the same market data as Washington Gas. Valuations are generally based on pricing service data or indicative broker quotes depending on the market location. We measure the net credit exposure at the counterparty level where the right to set-off exists. The net exposure is determined using the mark-to-market exposure adjusted for collateral, letters of credit and parent guarantees. We use published default rates from Standard & Poor’s Ratings Services and Moody’s Investors Service as inputs for determining credit adjustments. ASC Topic 820 establishes a fair value hierarchy that prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The three levels of the fair value hierarchy under ASC Topic 820 are described below: Level 1. Level 1 of the fair value hierarchy consists of assets or liabilities that are valued using observable inputs based upon unadjusted quoted prices in active markets for identical assets or liabilities at the reporting date. Washington Gas did not have any Level 1 derivatives at September 30, 2019 or December 31, 2018 . Level 2. Level 2 of the fair value hierarchy consists of assets or liabilities that are valued using directly or indirectly observable inputs either corroborated with market data or based on exchange traded market data. Level 2 includes fair values based on industry-standard valuation techniques that consider various assumptions: (i) quoted forward prices, including the use of mid-market pricing within a bid/ask spread; (ii) discount rates; (iii) implied volatility and (iv) other economic factors. Substantially all of these assumptions are observable throughout the full term of the instrument, can be derived from observable data or are supported by observable levels at which transactions are executed in the relevant market. At September 30, 2019 and December 31, 2018 , Level 2 financial assets and liabilities included energy-related physical and financial derivative transactions such as forward, option and other contracts for deliveries at active market locations. Level 3. Level 3 of the fair value hierarchy consists of assets or liabilities that are valued using significant unobservable inputs at the reporting date. These unobservable assumptions reflect our assumptions about estimates that market participants would use in pricing the asset or liability, including natural gas basis prices and annualized volatilities of natural gas prices. A significant change to any one of these inputs in isolation could result in a significant upward or downward fluctuation in the fair value measurement. These inputs may be used with industry standard valuation methodologies that result in our best estimate of fair value for the assets or liabilities at the reporting date. Our Commodity and Market Risk (C&MR) Group determines the valuation policies and procedures. The C&MR Group reports to A ltaGas ’ Vice President of Commodity Risk. In accordance with Washington Gas valuation policy, we may utilize a variety of valuation methodologies to determine the fair value of Level 3 derivative contracts, including internally developed valuation inputs and pricing models. The prices used in our valuations are corroborated using multiple pricing sources, and we periodically conduct assessments to determine whether each valuation model is appropriate for its intended purpose. The C&MR Group also evaluates changes in fair value measurements on a daily basis. At September 30, 2019 and December 31, 2018 , Level 3 derivative assets and liabilities included: (i) physical contracts valued at illiquid market locations with no observable market data; (ii) long-dated positions where observable pricing is not available over the majority of the life of the contract; (iii) contracts valued using historical spot price volatility assumptions and (iv) valuations using indicative broker quotes for inactive market locations. The following table sets forth financial instruments recorded at fair value as of September 30, 2019 and December 31, 2018 , respectively. A financial instrument’s classification within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy. Fair Value Measurements Under the Fair Value Hierarchy (In millions) Level 1 Level 2 Level 3 Total At September 30, 2019 Assets Natural gas related derivatives $ — $ 1.6 $ 10.0 $ 11.6 Total Assets $ — $ 1.6 $ 10.0 $ 11.6 Liabilities Natural gas related derivatives $ — $ (1.1 ) $ (116.3 ) $ (117.4 ) Total Liabilities $ — $ (1.1 ) $ (116.3 ) $ (117.4 ) At December 31, 2018 Assets Natural gas related derivatives $ — $ 9.8 $ 28.3 $ 38.1 Total Assets $ — $ 9.8 $ 28.3 $ 38.1 Liabilities Natural gas related derivatives $ — $ (9.5 ) $ (134.9 ) $ (144.4 ) Total Liabilities $ — $ (9.5 ) $ (134.9 ) $ (144.4 ) The following table includes quantitative information about the significant unobservable inputs used in the fair value measurement of our Level 3 financial instruments and the respective fair values of the net derivative asset and liability positions, by contract type, as of September 30, 2019 and December 31, 2018 . Quantitative Information about Level 3 Fair Value Measurements (In millions) Net Fair Value Valuation Techniques Unobservable Inputs Range Natural gas related derivatives ($106.3) Discounted Cash Flow Natural Gas Basis Price (per dekatherm) ($1.095) - $3.473 Net Fair Value Natural gas related derivatives ($106.6) Discounted Cash Flow Natural Gas Basis Price ($1.028)-$5.34 The following table presents a summary of the changes in the fair value of our derivative instruments that are measured at net fair value on a recurring basis in accordance with ASC Topic 820 using significant Level 3 inputs during the three and nine months ended September 30, 2019 and 2018, respectively. Reconciliation of Fair Value Measurements Using Significant Level 3 Inputs (In millions) Total - Natural Gas Three Months Ended September 30, 2019 Balance at July 1, 2019 $ (86.9 ) Realized and unrealized gains (losses) Recorded to income (6.2 ) Recorded to regulatory assets—gas costs (10.1 ) Transfers into Level 3 (2.9 ) Transfers out of Level 3 2.9 Purchases — Sales — Settlements (3.1 ) Balance at September 30, 2019 $ (106.3 ) Three Months Ended September 30, 2018 Balance at July 1, 2018 $ (103.6 ) Realized and unrealized gains (losses) Recorded to income 3.5 Recorded to regulatory assets—gas costs 5.6 Transfers into Level 3 (0.1 ) Transfers out of Level 3 (0.1 ) Purchases — Settlements 0.6 Balance at September 30, 2018 $ (94.1 ) Nine Months Ended September 30, 2019 Balance at January 1, 2019 $ (106.6 ) Realized and unrealized gains (losses) Recorded to income (1.4 ) Recorded to regulatory assets—gas costs 4.3 Transfers into Level 3 (6.7 ) Transfers out of Level 3 7.9 Purchases — Settlements (3.8 ) Balance at September 30, 2019 $ (106.3 ) Nine Months Ended September 30, 2018 Balance at January 1, 2018 $ (125.4 ) Realized and unrealized gains (losses) Recorded to income (0.7 ) Recorded to regulatory assets—gas costs (3.1 ) Transfers into Level 3 (7.1 ) Transfers out of Level 3 8.9 Settlements 33.3 Balance at September 30, 2018 $ (94.1 ) Transfers between different levels of the fair value hierarchy may occur based on fluctuations in the valuation inputs and on the level of observable inputs used to value the instruments from period to period. It is our policy to show both transfers into and out of the different levels of the fair value hierarchy at the fair value as of the beginning of the period. Transfers out of Level 3 during the three and nine months ended September 30, 2019 and 2018 were due to valuations that experienced an increase in observable market inputs. Transfers into Level 3 during the three and nine months ended September 30, 2019 and 2018 were due to an increase in unobservable market inputs, primarily pricing points. The table below sets forth the line items on the statements of operations to which amounts are recorded for the three and nine months ended September 30, 2019 and 2018, respectively, related to fair value measurements using significant Level 3 inputs. Realized and Unrealized Gains (Losses) Recorded to Income for Level 3 Measurements (In millions) Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Utility cost of gas $(6.2) $3.5 $(1.4) $(0.7) Unrealized gains (losses) attributable to derivative assets and liabilities measured using significant Level 3 inputs were recorded as follows for the three and nine months ended September 30, 2019 and 2018, respectively. Unrealized Gains (Losses) Recorded for Level 3 Measurements (In millions) Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Recorded to income Utility cost of gas $ (5.9 ) $ 3.1 $ 1.6 $ 6.9 Recorded to regulatory assets—gas costs (10.2 ) 4.8 7.9 7.7 Total $ (16.1 ) $ 7.9 $ 9.5 $ 14.6 The following table presents the carrying amounts recorded at amortized cost and estimated fair values of our financial instruments at September 30, 2019 and December 31, 2018 . Fair Value of Financial Instruments September 30, 2019 December 31, 2018 (In millions) Carrying Amount Fair Value Carrying Amount Fair Value Money market funds (a) $ 48.7 $ 48.7 $ 69.7 $ 69.7 Commercial paper (b) $ 117.0 $ 117.0 $ 296.0 $ 296.0 Project financing (b) $ — $ — $ 15.5 $ 15.5 Current maturities of long-term debt $ 50.0 $ 50.0 $ 50.0 $ 50.0 Long-term debt (c) $ 1,331.1 $ 1,501.5 $ 1,035.0 $ 1,096.3 (a) The balance as of September 30, 2019 includes $0.6 million money market funds located in “Cash and cash equivalents,” $4.2 million rabbi trust investment located in “Current Assets-Other,” and $43.9 million rabbi trust investments located in “Deferred Charges and Other Assets-Other” of the accompanying balance sheet; The balance as of December 31, 2018 includes $4.4 million money market funds located in “Cash and cash equivalents,” $ 20.2 million rabbi trust investment located in “Current Assets-Other” and $45.1 million rabbi trust investments located in “Deferred Charges and Other Assets-Other.” The amounts in cash and cash equivalent may be offset by outstanding checks. (b) Balance is located in “Notes payable and project financing” in the accompanying balance sheet. (c) Includes adjustments for current maturities and unamortized discounts, as applicable. Our money market funds are Level 1 valuations and their carrying amount approximates fair value. The maturity of our commercial paper outstanding at both September 30, 2019 and December 31, 2018 is under 30 days. Due to the short term nature of these notes, the carrying cost of our commercial paper approximates fair value using Level 2 inputs. Due to the nature of our project financing arrangements, the carrying cost approximates fair value using Level 2 inputs. Due to the short term nature of current maturities of long-term debt, the carrying cost approximates fair value using Level 2 inputs, Washington Gas’ long-term debt is not actively traded. The fair value of long-term debt was estimated based on valuation techniques when observable market data is not available. Our long-term debt fair value measurement is classified as Level 3.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS Corporate Service Allocation As a subsidiary of AltaGas and effective with the close of the Merger on July 6, 2018, Washington Gas is charged a proportionate share of corporate governance and other shared services costs from AltaGas, primarily related to human resources, employee benefits, finance, legal, accounting, tax, information technology services, and office services. AltaGas charges Washington Gas for the total shared service costs attributable to WGL and its affiliates and Washington Gas in turn allocates a portion of the costs to WGL’s other subsidiaries based on methodologies further described below. Washington Gas records a payable of the total shared service costs allocated to all WGL’s subsidiaries in “Payable to associated companies” and a receivable of the shared service costs allocated to WGL’s other subsidiaries in “Receivables from associated companies” on the balance sheet. As of September 30, 2019 , W ashington Gas recorded a $ 15.9 million liability to “Payables to associated companies,” reflecting Washington Gas’ unpaid shared service cost payable to AltaGas, and a receivable of $ 3.4 million to “Receivables from associated companies” on the balance sheet related to the shared service costs allocated to WGL’s subsidiaries. The net expenses of $ 5.0 million and $ 12.5 million were included in “Operation and maintenance” on the statements of operations for the three and nine months ended September 30, 2019 , respectively, reflecting the shared service cost allocated to Washington Gas. As of December 31, 2018 , Washington Gas recorded a receivable of $ 0.6 million to “Receivables from associated companies” on the balance sheet related to the shared service costs allocated to WGL’s subsidiaries. There was no payable balance related to the shared service cost payable to AltaGas as of December 31, 2018 . In addition, Washington Gas provides accounting, treasury, legal and other administrative and general support to WGL’s subsidiaries, and files consolidated tax returns that include affiliated taxable transactions. Effective upon the approvals by the SCC of Virginia and beginning in January 2019 and June 2019, respectively, Washington Gas also provides accounting, legal, tax and other administrative and general support to various AltaGas U.S. entities and AltaGas. Washington Gas bills affiliates to which it provides services in accordance with regulatory requirements for the actual cost of providing these services, which approximates their market value. To the extent such billings are outstanding, they are reflected in “Receivables from associated companies” on Washington Gas’ balance sheet. Washington Gas assigns or allocates these costs directly to its affiliates and, therefore, does not recognize revenues or expenses associated with providing these services. Washington Gas believes that allocations based on broad measures of business activity are appropriate for allocating expenses resulting from common services. Affiliate entities are allocated a portion of common services based on a formula driven by appropriate indicators of activity, as approved by management. Project Financing Washington Gas previously obtained third-party project financing on behalf of the federal government to provide funds during the construction of certain energy management services projects entered into under Washington Gas’ area-wide contract. Washington Gas recorded a contract asset in “Unbilled revenues” representing the government’s obligation and an account payable to WGL Energy Systems in “Payable to associated companies” for the construction work performed for the same amount. Refer to Note 5- Short Term Debt of the Notes to Condensed Financial Statements for further discussions of the project financing. Related Party Transactions with Hampshire Hampshire owns full and partial interests in underground natural gas storage facilities, including pipeline delivery facilities located in and around Hampshire County, West Virginia, and operates those facilities to serve Washington Gas, which purchases all of the storage services of Hampshire. Washington Gas includes the cost of these services in the bills sent to its customers and records the cost of the services in “Operation and maintenance” in its statements of operations. Hampshire operates under a “pass-through” cost of service-based tariff approved by the Federal Energy Regulatory Commission ( FERC) and adjusts its billing rates to Washington Gas on a periodic basis to account for changes in its investment in utility plant and associated expenses. The arrangement between Hampshire and Washington Gas is classified as an operating lease. An ROU asset and lease liability was not recognized upon the adoption of ASC 842 because all the costs associated with the arrangement are variable. Washington Gas recorded expenses related to the cost of services provided by Hampshire in Washington Gas’ statements of operations of $ 1.5 million and $ 5.5 million for the three and nine months ended in September 30, 2019, and $ 1.9 million and $ 5.3 million for the three and nine months ended in September 30, 2018, respectively. The outstanding balance not cleared between Washington Gas and Hampshire at the end of the reporting period was recorded in “Receivables from associated companies” on Washington Gas’ balance sheet. Refer to Note 3- Leases for further discussion of ASC 842. Other Related Party Transactions In connection with billing for unregulated third-party marketers, including WGL Energy Services and with other miscellaneous billing processes, Washington Gas collects cash on behalf of affiliates and transfers the cash in a reasonable time period. Cash collected by Washington Gas on behalf of its affiliates but not yet transferred is recorded in “Payables to associated companies” on Washington Gas’ balance sheet. Washington Gas provides gas balancing services related to storage, injections, withdrawals and deliveries to all energy marketers participating in the sale of natural gas on an unregulated basis through the customer choice programs that operate in its service territory. These balancing services include the sale of natural gas supply commodities related to various peaking arrangements contractually supplied to Washington Gas and then partially allocated and assigned by Washington Gas to the energy marketers, including WGL Energy Services. Washington Gas records revenues for these balancing services pursuant to tariffs approved by the appropriate regulatory bodies. The following table shows the amounts Washington Gas charged WGL Energy Services for balancing services. Gas Balancing Service Charges Three Months Ended Nine Months Ended (In millions) 2019 2018 2019 2018 Gas balancing service charge $ 2.9 $ 3.2 $ 14.9 $ 16.0 As a result of these balancing services, an imbalance is created for volumes of natural gas received by Washington Gas that are not equal to the volumes of natural gas delivered to customers of the energy marketers. Washington Gas recorded a $2.1 million payable to WGL Energy Services at September 30, 2019 and $0.7 million receivable from WGL Energy Services at December 31, 2018 , related to an imbalance in gas volumes. The receivable and payable are recorded in “Account receivable” and “Account payable and other accrued liabilities” on Washington Gas’ balance sheet. Refer to Note 1 - Accounting Policies of the Notes to Financial Statements on Form 10-K T for the three months ended December 31, 2018 for further discussion of these imbalance transactions. Washington Gas participates in a purchase of receivables (POR) program as approved by the PSC of MD and the PSC of DC, whereby it purchases receivables from participating energy marketers, including WGL Energy Services, at approved discount rates. Washington Gas implemented the POR program in the District of Columbia beginning in January 2019. The receivables purchased by Washington Gas are included in “Accounts receivable” in the accompanying balance sheet. At September 30, 2019 and December 31, 2018 , Washington Gas had balances of $3.5 million and $ 6.4 million , respectively, of purchased receivables from WGL Energy Services. Refer to Note 8- Income Taxes of the Notes to Condensed Financial Statements for discussion of related party income taxes.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The following table shows the changes in accumulated other comprehensive income (loss) by component for three and nine months ended September 30, 2019 and 2018 . Changes in Accumulated Other Comprehensive Income (Loss) by Component Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2019 2018 2019 2018 Beginning Balance $ (6,141 ) $ (3,959 ) $ (6,627 ) $ (4,330 ) Amortization of prior service cost (a)(b) (163 ) 145 (486 ) (401 ) Amortization of actuarial gain (loss) (a)(b) 392 112 1,198 1,172 Actuarial gain (loss) arising during the period (a) — 4,625 1,250 4,625 Current-period other comprehensive income (loss) 229 4,882 1,962 5,396 Income tax expense (benefit) related to pension and other post-retirement benefit plans (713 ) 2,753 534 2,896 Ending Balance $ (5,199 ) $ (1,830 ) $ (5,199 ) $ (1,830 ) (a) These accumulated other comprehensive income (loss) components are included in the computation of net periodic benefit cost. Refer to Note 9—Pension and other post-retirement benefit plans for additional details. (b) Amortization of prior service cost and amortization of actuarial gain (loss) represent the amounts reclassified out of AOCI to “Other income (expense)” of Statements of Operations for the reporting periods.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2019
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	SUPPLEMENTAL CASH FLOW INFORMATION The following table details the changes in operating assets and liabilities from operating activities, cash payments that have been included in the determination of earnings and non-cash investing and financing activities. Nine Months Ended September 30, Nine Months Ended September 30, (In thousands) 2019 2018 CHANGES IN OPERATING ASSETS AND LIABILITIES Accounts receivable and unbilled revenues $ 174,986 $ 159,066 Receivables from associated companies (3,981 ) 24,783 Gas costs and other regulatory assets/liabilities—net (8,253 ) (10,509 ) Storage gas 11,479 (16,419 ) Prepaid taxes (3,791 ) 14,167 Accounts payable and other accrued liabilities (109,287 ) 15,722 Payables to associated companies 10,383 (86,049 ) Customer deposits and advance payments (11,511 ) 28,947 Accrued taxes 6,830 (19,527 ) Other current assets 5,077 (4,701 ) Other current liabilities (240 ) 278 Deferred gas costs—net 49,379 17,717 Deferred assets—other 11,807 11,754 Deferred liabilities—other (26,879 ) (22,038 ) Pension and other post-retirement benefits (11,427 ) (14,079 ) Other—net — (798 ) Changes in operating assets and liabilities $ 94,572 $ 98,314 SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION Income taxes paid (refunded)—net $ 5,253 $ (2,025 ) Interest paid $ 54,238 $ 54,059 SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES: Extinguishment of project debt financing $ (15,460 ) $ (28,312 ) Capital expenditure accruals included in accounts payable and other accrued liabilities $ 39,976 $ 53,367 The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within Washington Gas’ balance sheet that sums to the total of such amounts shown on the statements of cash flows. (in thousands) September 30, 2019 September 30, 2018 Cash and cash equivalents $ 1 $ 1 Restricted cash included in Current Assets-Other $ 4,225 $ 20,207 Restricted cash included in Deferred Charges and Other Assets-Other $ 43,945 $ 44,775 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 48,171 $ 64,983 Restricted cash included in “Current assets—Other” and “Deferred charges and other assets—Other” on the balance sheet represents amount of investment in rabbi trusts to fund deferred compensation, pension and other post-retirement benefits for certain management personnel and directors. The rabbi trusts were funded pursuant to the agreement of merger with AltaGas. The funds in the rabbi trusts can only be used to pay for plan participant benefits and other plan expenses such as investment fees or trustee fees. The funds were invested in money market funds a t September 30, 2019 and September 30, 2018 . Refer to Note 9- Pension and Other Post-Retirement Benefit Plans for further discussion of rabbi trusts.

Accounting Policies (Policies)

Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Consolidation	Washington Gas is an indirect, majority owned subsidiary of, among other entities, AltaGas and WGL. On July 6, 2018, a merger of WGL into AltaGas was consummated (the Merger). In connection with the Merger, WGL, the former parent entity of Washington Gas, formed a wholly owned subsidiary, Wrangler SPE LLC (Wrangler), a bankruptcy remote, special purpose entity to own the common stock of Washington Gas, which survived the Merger as an indirect, wholly owned subsidiary of AltaGas. In addition, WGL owns all of the shares of common stock of Washington Gas Resources Corporation (Washington Gas Resources) and Hampshire Gas Company (Hampshire). Washington Gas Resources owns all of the shares of common stock of four non-utility subsidiaries that include WGL Energy Services, Inc. (WGL Energy Services), WGL Energy Systems, Inc. (WGL Energy Systems), WGL Midstream, Inc. (WGL Midstream) and WGSW, Inc. (WGSW). Additionally, several subsidiaries of WGL own interests in other entities.
Basis of Accounting, Policy	The condensed financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Therefore, certain financial information and note disclosures accompanying annual financial statements prepared in accordance with generally accepted accounting principles in the United States of America (GAAP) are omitted in this interim report.
Operating Leases	For our multiple office location leases classified as operating leases, the lease term begins on the date when construction of the leasehold improvements can start and the lessor has allowed us to occupy the respective locations. Leasehold improvement costs are classified as “Property, Plant, and Equipment” on the balance sheet, and are being amortized to “Depreciation and amortization” expense on a straight-line basis over the non-cancelable period of the leases. We determine if an arrangement is a lease and the lease classification at inception. Lease payments under operating leases are recognized on a straight-line basis over the lease term. For our building leases, we do not separate the lease and non-lease components.
Accounting Standards Adopted Current Fiscal Year [Policy Text Block]	ACCOUNTING STANDARDS ADOPTED IN CALENDAR YEAR ASU 2016-02, Leases (Topic 842), ASU 2018-01, Land Easement Practical Expedient for Transition to Topic 842, ASU 2018-11, Targeted Improvements, and ASU 2018-20, Narrow-Scope Improvements for Lessors, including other subsequent ASUs clarifying the guidance. ASU 2016-02 requires recognition of a right-to-use asset and lease liability by lessees on the statement of financial position and disclosure of key information about leasing arrangements. Lessor accounting remains substantially unchanged but the standard modifies what qualifies as a sales-type and direct financing lease and eliminated real-estate specific provisions. The standard requires application using a modified retrospective approach. January 1, 2019 Leases, with terms longer than 12 months, for which Washington Gas is the lessee have been reflected on the balance sheet by recording an increase to non- current assets and an increase to deferred credits net of the current portion that is recorded in current liabilities. Upon adoption, Washington Gas recorded lease liabilities of $58.9 million and a right-of-use asset of $43.2 million, net of lease incentives and prepaid or deferred rent balances of $15.7 million. Washington Gas utilized the transition practical expedients which allow entities to not have to reassess whether an arrangement contains a lease and the lease classification under the provisions of ASC Topic 842, land easements, and not separating out the lease and non-lease components for certain classes of assets. As a result of the transition practical expedients, Washington Gas’ operating leases on transition are consistent with its conclusions under ASC 840. Washington Gas has also elected to present prior comparative information under ASC 840. See Note 3 - Leases for further information and the new required lease disclosures. ______________________________________________________________________________________________________ ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted improvements to Accounting for Hedging Activities and ASU 2018-16, Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes ASU 2017-12 amends the hedge accounting and recognition requirements by expanding an entity’s ability to hedge non-financial and financial risk components and reduce the complexity in fair value hedges of interest rate risk. Additionally, this standard eliminates the requirement to separately measure and disclose the ineffective portion of the hedge with the entire change in the fair value of a hedging instrument to be presented in the same statement of operations line as the hedged item. Early adoption is permitted. January 1, 2019 The guidance will only have an impact on new transactions that are entered into and where hedge accounting is elected. ____________________________________________________________________________________________________ ASU 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (a consensus of the FASB Emerging Issues Task Force) The update aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements to capitalize implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). Capitalized implementation costs should be presented in the statement of financial position as a prepaid expense and amortized over the term of the hosting arrangement, presented in the statements of operations in the same line items as prepayment of fees associated with the hosting arrangement. The updates in this standard may be applied on a prospective or retrospective basis. Early adoption is permitted. January 1, 2019 We early adopted this standard on a prospective basis. The adoption of this ASU did not have a material effect on our financial statements. ______________________________________________________________________________________________________
New Accounting Pronouncements, Policy [Policy Text Block]	OTHER NEWLY ISSUED ACCOUNTING STANDARDS ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, including other subsequent ASUs clarifying the guidance. For credit losses on financial instruments, this standard changes the current incurred loss impairment methodology to an expected loss methodology and requires consideration of a broader range of reasonable and supportable information to determine credit loss estimates. Early adoption is permitted. January 1, 2020 We are in the process of evaluating the impact the adoption of this standard will have on our financial statements. _____________________________________________________________________________________________________ ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement This update modifies the disclosure requirements on fair value measurements. Early adoption is permitted. January 1, 2020 It is not expected that the adoption of this standard will have a material effect on our financial statements. _____________________________________________________________________________________________________ ASU 2018-17, Consolidation (Topic 810): Targeted Improvements to Related Party Guidance for Variable Interest Entities This standard provides a private-company scope exception to the VIE guidance for certain entities under common control and clarify that indirect interest held through related parties under common control will be considered on a proportional basis when determining whether fees paid to decision makers and service providers are variable interests. Early adoption is permitted. January 1, 2020 We are in the process of evaluating this new accounting standard but it is expected that the adoption of this standard will not have a material effect on our financial statements. ______________________________________________________________________________________________________ ASU 2019-01, Leases (Topic 842) Codification Improvements This update addresses the determination of the fair value of the underlying asset by lessors that are not manufacturers or dealers, provides guidance for the presentation of the statement of cash flows for sales-type and direct financing leases, and clarifies transition disclosures related to Topic 250. January 1, 2020 We do not anticipate that adoption of this standard will have a material effect on our financial statements. ______________________________________________________________________________________________________ ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans This standard modifies the disclosure requirements related to defined benefit pension and other postretirement plans. Early adoption is permitted. December 31, 2020 We do not anticipate that adoption of this standard will have a material effect on our financial statements. ______________________________________________________________________________________________________

Revenue from Contracts With C_2

Revenue from Contracts With Customers (Policies)	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Customer billings are based on two main components: (i) a fixed service fee and (ii) a variable fee based on usage. For customers who choose to purchase their natural gas from Washington Gas, the bill will include a usage based charge for the cost of the commodity. Revenue is recognized over time as the natural gas is delivered or as the service is performed. As meter readings are performed on a cycle basis, Washington Gas recognizes accrued revenue for any services rendered to its customers but not billed at month-end. The tariff sales are generally considered daily or “at-will” contracts as customers may cancel their service at any time (subject to notification requirements in the tariff), and revenue generally represents the amount Washington Gas is entitled to invoice. There are certain contracts that have terms of one year or longer. For these contracts, revenue is recognized based on the amount Washington Gas is entitled to bill the customer. Customers have the choice to purchase natural gas from competitive service providers. Washington Gas charges the competitive service providers balancing fees to manage the natural gas transportation imbalances. Where regulations require, Washington Gas issues customers a consolidated bill to include the natural gas supplied by the competitive service providers and distribution of natural gas. Washington Gas recognizes revenue only for distribution services that it has provided to the customer, and the balancing fees for the services provided to the competitive service provider.
Unbilled revenue	Washington Gas accrues unbilled revenues for gas delivered, but not yet billed at the end of each accounting period due to our customer billing cycles. “Unbilled revenues” represent performance obligations that have been satisfied and to which Washington Gas has an unconditional right to payment, except for contract assets related to Washington Gas’ area-wide contract, which requires project acceptance by federal government for the right to payment to occur.

Short-Term Debt (Policies)

Short-Term Debt (Policies)	9 Months Ended
	Sep. 30, 2019
Short-term Debt [Abstract]
Short Term Debt Policy	Washington Gas satisfies its short-term financing requirements through the sale of commercial paper, financing arrangements with third-party lenders, or bank borrowings. Due to the seasonal nature of our operations, short-term financing requirements can vary significantly during the year. Revolving credit agreements are maintained to support outstanding commercial paper and to permit short-term borrowing flexibility. The policy of Washington Gas is to maintain bank credit facilities in amounts equal to or greater than the expected maximum commercial paper position. Washington Gas issues long-term debt in the form of medium-term notes (MTNs), unsecured long-term notes and private placement notes, all of which contain individual terms regarding interest rates, maturities and call or put options. Each of these note types can have maturity dates of one or more years from the date of issuance.

Long-Term Debt Long-Term Debt (

Long-Term Debt Long-Term Debt (Policies)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Long Term Debt Policy	Washington Gas satisfies its short-term financing requirements through the sale of commercial paper, financing arrangements with third-party lenders, or bank borrowings. Due to the seasonal nature of our operations, short-term financing requirements can vary significantly during the year. Revolving credit agreements are maintained to support outstanding commercial paper and to permit short-term borrowing flexibility. The policy of Washington Gas is to maintain bank credit facilities in amounts equal to or greater than the expected maximum commercial paper position. Washington Gas issues long-term debt in the form of medium-term notes (MTNs), unsecured long-term notes and private placement notes, all of which contain individual terms regarding interest rates, maturities and call or put options. Each of these note types can have maturity dates of one or more years from the date of issuance.

Income Taxes Income Taxes (Poli

Income Taxes Income Taxes (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Income Taxes Policy	Washington Gas is included in the ASUS consolidated income tax returns beginning with the period from July 7, 2018 to December 31, 2018. We have established a new tax sharing policy with ASUS.

Derivative and Weather Relate_2

Derivative and Weather Related Instruments (Policies)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives, Policy	Washington Gas enters into contracts that qualify as derivative instruments and are accounted for under ASC Topic 815. These derivative instruments are recorded at fair value on our balance sheet and Washington Gas does not currently designate any derivatives as hedges under ASC Topic 815. Washington Gas’ derivative instruments relate to: (i) Washington Gas’ asset optimization program; (ii) managing price risk associated with the purchase of gas to serve utility customers and (iii) managing interest rate risk. Asset Optimization. Washington Gas optimizes the value of its long-term natural gas transportation and storage capacity resources during periods when these resources are not being used to physically serve utility customers. Specifically, Washington Gas utilizes its transportation capacity assets to benefit from favorable natural gas prices between different geographic locations and utilizes its storage capacity assets to benefit from favorable natural gas prices between different time periods. As part of this asset optimization program, Washington Gas enters into physical and financial derivative transactions in the form of forward, futures and option contracts with the primary objective of securing operating margins that Washington Gas will ultimately realize. The derivative transactions entered into under this program are subject to mark-to-market accounting treatment under ASC Topic 820. Regulatory sharing mechanisms provide for the annual realized profit from these transactions to be shared between Washington Gas’ shareholders and customers; therefore, changes in fair value are recorded through earnings, or as regulatory assets or liabilities to the extent that it is probable that realized gains and losses associated with these derivative transactions will be included in the rates charged to customers when they are realized. Unrealized gains and losses recorded to earnings may cause significant period-to-period volatility; this volatility does not change the operating margins that Washington Gas expects to ultimately realize from these transactions through the use of its storage and transportation capacity resources.
Risk, Policy	Managing Price Risk. To manage price risk associated with acquiring natural gas supply for utility customers, Washington Gas enters into physical and financial derivative transactions in the form of forward, option and other contracts, as authorized by its regulators. Any gains and losses associated with these derivatives are recorded as regulatory liabilities or assets, respectively, to reflect the rate treatment for these economic hedging activities. Managing Interest-Rate Risk. Washington Gas may utilize derivative instruments that are designed to minimize the risk of interest-rate volatility associated with planned issuances of debt securities. Any gains and losses associated with these types of derivatives are recorded as regulatory liabilities or assets, respectively, and amortized in accordance with regulatory requirements, typically over the life of the related debt.
Collateral, Policy	Washington Gas utilizes standardized master netting agreements, which facilitate the netting of cash flows into a single net exposure for a given counterparty. As part of these master netting agreements, cash, letters of credit and parent company guarantees may be required to be posted or obtained from counterparties in order to mitigate credit risk related to both derivatives and non-derivative positions. Under Washington Gas’ offsetting policy, collateral balances are offset against the related counterparties’ derivative positions to the extent the application would not result in the over-collateralization of those derivative positions on the balance sheet. We are exposed to credit risk from derivative instruments with wholesale counterparties, which is represented by the fair value of these instruments at the reporting date. We actively monitor and work to minimize counterparty concentration risk through various practices. Concentration of Credit Risk We are exposed to credit risk from derivative instruments with wholesale counterparties, which is represented by the fair value of these instruments at the reporting date. We actively monitor and work to minimize counterparty concentration risk through various practices. Washington Gas utilizes standardized master netting agreements, which facilitate the netting of cash flows into a single net exposure for a given counterparty. As part of these master netting agreements, cash, letters of credit and parent company guarantees may be required to be posted or obtained from counterparties in order to mitigate credit risk related to both derivatives and non-derivative positions. Under Washington Gas’ offsetting policy, collateral balances are offset against the related counterparties’ derivative positions to the extent the application would not result in the over-collateralization of those derivative positions on the balance sheet. Any collateral posted that is not offset against derivative assets and liabilities is included in “Other prepayments” in the condensed balance sheet. Collateral received and not offset against derivative assets and liabilities is included in “Customer deposits and advance payments” in the accompanying condensed balance sheet.

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Fair Value Measurement Policy	We measure the fair value of our financial assets and liabilities using a combination of the income and market approaches in accordance with ASC Topic 820. These financial assets and liabilities primarily consist of derivatives recorded on our balance sheet under ASC Topic 815 and short-term investments, commercial paper and long-term debt outstanding required to be disclosed at fair value. Under ASC Topic 820, fair value is defined as the exit price, representing the amount that would be received in the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. To value our financial instruments, we use market data or assumptions that market participants would use, including assumptions about credit risk (both our own credit risk and the counterparty’s credit risk) and the risks inherent in the inputs to valuation. We enter into derivative contracts in the futures and over-the-counter (OTC) wholesale and retail markets. These markets are the principal markets for the respective wholesale and retail contracts. Our relevant market participants are our existing counterparties and others who have participated in energy transactions at our delivery points. These participants have access to the same market data as Washington Gas. Valuations are generally based on pricing service data or indicative broker quotes depending on the market location. We measure the net credit exposure at the counterparty level where the right to set-off exists. The net exposure is determined using the mark-to-market exposure adjusted for collateral, letters of credit and parent guarantees. We use published default rates from Standard & Poor’s Ratings Services and Moody’s Investors Service as inputs for determining credit adjustments. A financial instrument’s classification within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy. Washington Gas valuation policy, we may utilize a variety of valuation methodologies to determine the fair value of Level 3 derivative contracts, including internally developed valuation inputs and pricing models. The prices used in our valuations are corroborated using multiple pricing sources, and we periodically conduct assessments to determine whether each valuation model is appropriate for its intended purpose. The C&MR Group also evaluates changes in fair value measurements on a daily basis.
Fair Value Transfer, Policy	Transfers between different levels of the fair value hierarchy may occur based on fluctuations in the valuation inputs and on the level of observable inputs used to value the instruments from period to period. It is our policy to show both transfers into and out of the different levels of the fair value hierarchy at the fair value as of the beginning of the period. Transfers out of Level 3 during the three and nine months ended September 30, 2019 and 2018 were due to valuations that experienced an increase in observable market inputs. Transfers into Level 3 during the three and nine months ended September 30, 2019 and 2018 were due to an increase in unobservable market inputs, primarily pricing points.
Fair Value of Financial Instruments, Policy	Our money market funds are Level 1 valuations and their carrying amount approximates fair value. The maturity of our commercial paper outstanding at both September 30, 2019 and December 31, 2018 is under 30 days. Due to the short term nature of these notes, the carrying cost of our commercial paper approximates fair value using Level 2 inputs. Due to the nature of our project financing arrangements, the carrying cost approximates fair value using Level 2 inputs. Due to the short term nature of current maturities of long-term debt, the carrying cost approximates fair value using Level 2 inputs, Washington Gas’ long-term debt is not actively traded. The fair value of long-term debt was estimated based on valuation techniques when observable market data is not available. Our long-term debt fair value measurement is classified as Level 3.

Accounting Policies (Tables)

Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Accounting standards adopted in the current fiscal year	The following tables summarize the Accounting Standards Updates (ASUs) adopted by Washington Gas during the nine months ended September 30, 2019 and other newly issued accounting standards that will be adopted by Washington Gas in the future. ACCOUNTING STANDARDS ADOPTED IN CALENDAR YEAR 2019 Standard Description Date of adoption Effect on the financial statements or other significant matters ASU 2016-02, Leases (Topic 842), ASU 2018-01, Land Easement Practical Expedient for Transition to Topic 842, ASU 2018-11, Targeted Improvements, and ASU 2018-20, Narrow-Scope Improvements for Lessors, including other subsequent ASUs clarifying the guidance. ASU 2016-02 requires recognition of a right-to-use asset and lease liability by lessees on the statement of financial position and disclosure of key information about leasing arrangements. Lessor accounting remains substantially unchanged but the standard modifies what qualifies as a sales-type and direct financing lease and eliminated real-estate specific provisions. The standard requires application using a modified retrospective approach. January 1, 2019 Leases, with terms longer than 12 months, for which Washington Gas is the lessee have been reflected on the balance sheet by recording an increase to non- current assets and an increase to deferred credits net of the current portion that is recorded in current liabilities. Upon adoption, Washington Gas recorded lease liabilities of $58.9 million and a right-of-use asset of $43.2 million, net of lease incentives and prepaid or deferred rent balances of $15.7 million. Washington Gas utilized the transition practical expedients which allow entities to not have to reassess whether an arrangement contains a lease and the lease classification under the provisions of ASC Topic 842, land easements, and not separating out the lease and non-lease components for certain classes of assets. As a result of the transition practical expedients, Washington Gas’ operating leases on transition are consistent with its conclusions under ASC 840. Washington Gas has also elected to present prior comparative information under ASC 840. See Note 3 - Leases for further information and the new required lease disclosures. ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted improvements to Accounting for Hedging Activities and ASU 2018-16, Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes ASU 2017-12 amends the hedge accounting and recognition requirements by expanding an entity’s ability to hedge non-financial and financial risk components and reduce the complexity in fair value hedges of interest rate risk. Additionally, this standard eliminates the requirement to separately measure and disclose the ineffective portion of the hedge with the entire change in the fair value of a hedging instrument to be presented in the same statement of operations line as the hedged item. Early adoption is permitted. ASU 2018-16 adds the OIS rate based on SOFR as a fifth U.S. benchmark interest rate for hedge accounting purposes. This standard should be adopted in conjunction with ASU 2017-12 if not early adopted. January 1, 2019 The guidance will only have an impact on new transactions that are entered into and where hedge accounting is elected. ASU 2018-15, Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (a consensus of the FASB Emerging Issues Task Force) The update aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements to capitalize implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). Capitalized implementation costs should be presented in the statement of financial position as a prepaid expense and amortized over the term of the hosting arrangement, presented in the statements of operations in the same line items as prepayment of fees associated with the hosting arrangement. The updates in this standard may be applied on a prospective or retrospective basis. Early adoption is permitted. January 1, 2019 We early adopted this standard on a prospective basis. The adoption of this ASU did not have a material effect on our financial statements.
Other newly issued accounting standards	OTHER NEWLY ISSUED ACCOUNTING STANDARDS Standard Description Required date of adoption Effect on the financial statements or other significant matters ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, including other subsequent ASUs clarifying the guidance. For credit losses on financial instruments, this standard changes the current incurred loss impairment methodology to an expected loss methodology and requires consideration of a broader range of reasonable and supportable information to determine credit loss estimates. Early adoption is permitted. January 1, 2020 We are in the process of evaluating the impact the adoption of this standard will have on our financial statements. ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement This update modifies the disclosure requirements on fair value measurements. Early adoption is permitted. January 1, 2020 It is not expected that the adoption of this standard will have a material effect on our financial statements. ASU 2018-17, Consolidation (Topic 810): Targeted Improvements to Related Party Guidance for Variable Interest Entities This standard provides a private-company scope exception to the VIE guidance for certain entities under common control and clarify that indirect interest held through related parties under common control will be considered on a proportional basis when determining whether fees paid to decision makers and service providers are variable interests. Early adoption is permitted. January 1, 2020 We are in the process of evaluating this new accounting standard but it is expected that the adoption of this standard will not have a material effect on our financial statements. ASU 2019-01, Leases (Topic 842) Codification Improvements This update addresses the determination of the fair value of the underlying asset by lessors that are not manufacturers or dealers, provides guidance for the presentation of the statement of cash flows for sales-type and direct financing leases, and clarifies transition disclosures related to Topic 250. January 1, 2020 We do not anticipate that adoption of this standard will have a material effect on our financial statements. ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans This standard modifies the disclosure requirements related to defined benefit pension and other postretirement plans. Early adoption is permitted. December 31, 2020 We do not anticipate that adoption of this standard will have a material effect on our financial statements.

Revenue from Contracts With C_3

Revenue from Contracts With Customers (Tables)	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table disaggregates revenue for the three and nine months ended September 30, 2019 . Disaggregated Revenue by Type of Service (In millions) Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Revenue from contracts with customers Gas and transportation sales Gas sold and delivered $ 70.7 $ 665.1 Gas delivered for others 33.4 186.8 Other 10.9 34.4 Other revenues 1.4 4.2 Total revenue from contracts with customers $ 116.4 $ 890.5 Other sources of revenue Revenue from alternative revenue programs (a) $ 3.6 $ 14.9 Leasing revenue (b) 0.2 0.5 Other 2.1 8.5 Total revenue from other sources 5.9 23.9 Total Operating Revenue $ 122.3 $ 914.4 (a) Washington Gas has determined that its Revenue Normalization Adjustment (RNA), Weather Normalization Adjustment (WNA), and Conservation and Ratemaking Efficiency (CARE) Ratemaking Adjustment (CRA) billing adjustment mechanisms and accelerated pipe replacement programs are alternative revenue programs and accounted for under ASC Topic 980. (b) Revenue generated from Washington Gas lessor operating leases accounted for under ASC Topic 842, Leases. See Note 3-Leases for further information on leases.

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	The following table provides our expected operating lease payments as of September 30, 2019 . Maturity of Operating Lease Liabilities (In millions) September 30, 2019 2019 $ 1.3 2020 5.9 2021 5.5 2022 5.5 2023 5.5 Thereafter 52.1 Total lease payments $ 75.8 Less: Interest (15.5 ) Present Value of Lease Liabilities $ 60.3
Lessee, Operating Lease, Supplemental Information [Table Text Block]	The following table provides supplemental cash flow information related to operating leases for the three and nine months ended September 30, 2019 . Supplemental Cash Flow Information Related to Operating Leases ($ in millions) Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Cash paid for amounts included in the lease liabilities in the operating cash flows $ 0.5 $ 1.5 Operating lease cost (including variable lease costs of $0.5 million and $1.5 million for the three and nine months ended September 30, 2019, respectively) $ 1.8 $ 5.4 Right-of-use assets obtained in exchange for new operating lease liabilities $ 0.4 $ 1.5
Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block]	The following table summarizes the future operating lease payments to be received associated with these leases. Maturity of Operating Lease Payments (a) (In millions) September 30, 2019 2019 $ 0.2 2020 0.7 2021 0.6 2022 0.6 2023 0.6 Thereafter 58.3 Total lease payments $ 61.0 (a) The payments are presented on an undiscounted basis

Accounts Payable and Other Ac_2

Accounts Payable and Other Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2019
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable and Other Accrued Liabilities	The table below provides details for the amounts included in “Accounts payable and other accrued liabilities” on the condensed balance sheet s . (In millions) September 30, 2019 December 31, 2018 Accounts payable—trade $ 139.4 $ 228.9 Employee benefits and payroll accruals 16.5 28.0 Other accrued liabilities 26.9 31.5 Total $ 182.8 $ 288.4

Short-Term Debt (Tables)

Short-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2019
Short-term Debt [Abstract]
Commited Credit Available	The following is a summary of committed credit available at September 30, 2019 and December 31, 2018 . Committed Credit Available ($ in millions) September 30, 2019 December 31, 2018 Committed credit agreements Unsecured revolving credit facility $ 450.0 $ 350.0 Less: Commercial paper outstanding (117.0 ) (296.0 ) Net committed credit available $ 333.0 $ 54.0 Weighted average interest rate 2.31 % 2.93 %

Long Term Debt (Tables)

Long Term Debt (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table Text Block]	The following table shows the outstanding notes as of September 30, 2019 and December 31, 2018 . Long-Term Debt Outstanding ($ in millions) September 30, 2019 December 31, 2018 Total Long-Term Debt (a) $ 1,396.0 $ 1,096.0 Unamortized discount (4.3 ) (2.9 ) Unamortized debt expense (10.6 ) (8.1 ) Less—current maturities 50.0 50.0 Total Long-Term Debt $ 1,331.1 $ 1,035.0 Weighted average interest rate (b) 4.53 % 4.77 % (a) Includes MTNs and private placement notes. The amount represents face value of long-term debt including current maturities. (b) Weighted average interest rate is for the long-term debt including current maturities.

Components of Total Equity (Tab

Components of Total Equity (Tables)	9 Months Ended
	Sep. 30, 2019
Components of Total Equity [Abstract]
Components of Total Equity Table	The tables below reflect the components of “Total equity” for the three and nine months ended September 30, 2019 and 2018 . . Components of Total Equity (In thousands, except shares) Common Stock Paid-In Capital Retained Earnings Accumulated Other Comprehensive Income (Loss), Net of Taxes Total Shares Amount Three Months Ended September 30, 2019 Balance at June 30, 2019 46,479,536 46,479 979,273 585,193 (6,141 ) $ 1,604,804 Net loss — — — (65,799 ) — $ (65,799 ) Other comprehensive income (loss) — — — — 942 $ 942 Dividends declared: Common stock — — — — — $ — Preferred stock — — — — — $ — Balance at September 30, 2019 46,479,536 46,479 979,273 519,394 (5,199 ) 1,539,947 Three Months Ended September 30, 2018 Balance at June 30, 2018 46,479,536 46,479 585,562 723,749 (3,959 ) 1,351,831 Net loss — — — (181,153 ) — $ (181,153 ) Other comprehensive income (loss) — — — — 3,613 $ 3,613 Stock-based compensation (a) — — (9,017 ) — — $ (9,017 ) Capital contribution from parent — 302,728 $ 302,728 ASU 2018-02 adoption impact (b) 1,484 (1,484 ) — Dividends declared: Common stock — — — (24,908 ) — $ (24,908 ) Preferred stock — — — (330 ) — $ (330 ) Balance at September 30, 2018 46,479,536 46,479 879,273 518,842 (1,830 ) 1,442,764 Nine Months Ended September 30, 2019 Balance at December 31, 2018 46,479,536 46,479 979,273 543,448 (6,627 ) 1,562,573 Net income — — — 26,606 — 26,606 Other comprehensive income (loss) — — — — 1,428 1,428 Dividends declared: Common stock — — — (50,000 ) — (50,000 ) Preferred stock — — — (660 ) — (660 ) Balance at September 30, 2019 46,479,536 46,479 979,273 519,394 (5,199 ) 1,539,947 Nine Months Ended September 30, 2018 Balance at December 31, 2017 46,479,536 46,479 583,185 670,580 (4,330 ) $ 1,295,914 Net income — — — (84,568 ) — $ (84,568 ) Other comprehensive income (loss) — — — — 3,984 $ 3,984 Stock-based compensation (a) — — (6,640 ) — — $ (6,640 ) Capital contribution from parent — — 302,728 — — $ 302,728 ASU 2018-02 adoption impact (b) $ 1,484 $ (1,484 ) — Dividends declared: Common stock — — — (67,664 ) — $ (67,664 ) Preferred stock — — — (990 ) — $ (990 ) Balance at September 30, 2018 46,479,536 46,479 879,273 518,842 (1,830 ) 1,442,764 (a) Stock-based compensation is based on the stock awards of WGL that are allocated to Washington Gas Light Company for its pro-rata share and includes implementation of ASU 2016-09. (b) Amount related to the adoption of ASU 2018-02. Washington Gas reclassified a credit of $ 1.5 million from AOCI to retained earnings at September 30, 2018.

Pension and Other Post-Retire_2

Pension and Other Post-Retirement Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2019
Retirement Benefits [Abstract]
Components of Net Periodic Benefit Costs (Income)	The following table shows the components of net periodic benefit costs (income) recognized in our financial statements during the three and nine months ended September 30, 2019 and 2018 : Components of Net Periodic Benefit Costs (Income) Three Months Ended September 30, 2019 2018 (In millions) Pension Benefits Health and Life Benefits Pension Benefits Health and Life Benefits Service cost $ 3.0 $ 1.3 $ 3.7 $ 1.3 Interest cost 10.2 3.0 9.9 2.9 Expected return on plan assets (10.7 ) (6.1 ) (10.6 ) (5.9 ) Recognized prior service cost (credit) 0.1 (3.9 ) 0.1 (4.4 ) Recognized actuarial loss 1.3 — 3.9 — Net periodic benefit cost (income) 3.9 (5.7 ) 7.0 (6.1 ) Allocation to affiliates (0.4 ) 0.5 (0.9 ) 0.7 Adjusted net periodic benefit cost (income) 3.5 (5.2 ) 6.1 (5.4 ) Amount allocated to construction projects (b) (0.4 ) (0.2 ) (1.0 ) 0.8 Amount deferred as regulatory asset (liability)-net allocations (c) — — 1.7 — Amount charged (credited) to expense $ 3.1 $ (5.4 ) $ 6.8 $ (4.6 ) Nine Months Ended September 30, 2019 2018 (In millions) Pension Benefits Health and Life Benefits Pension Benefits Health and Life Benefits Service cost $ 9.1 $ 3.8 $ 11.1 $ 3.9 Interest cost 30.7 9.0 29.7 8.7 Expected return on plan assets (32.1 ) (18.3 ) (31.7 ) (17.7 ) Recognized prior service cost (credit) 0.3 (11.7 ) 0.3 (13.2 ) Recognized actuarial loss 4.0 — 11.7 — Settlement charge (a) 4.3 — — — Net periodic benefit cost (income) 16.3 (17.2 ) 21.1 (18.3 ) Allocation to affiliates (1.3 ) 1.8 (2.6 ) 2.1 Adjusted net periodic benefit cost (income) 15.0 (15.4 ) 18.5 (16.2 ) Amount allocated to construction projects (b) (1.2 ) (0.6 ) (3.6 ) 2.9 Amount deferred as regulatory asset (liability)-net allocations (c) 0.7 — 4.7 — Amount charged (credited) to expense $ 14.5 $ (16.0 ) $ 19.6 $ (13.3 ) (a)Amount relates to a one - time partial settlement charge associated with a lump sum payment to Washington Gas’ defined benefit supplemental executive retirement plan (DB SERP) that was paid in the first quarter of 2019. (b)On October 1, 2018, Washington Gas adopted ASU 2017-07. As a result, only the service cost component of net periodic benefit costs (income) is eligible for capitalization. (c)Amount represents the amortization of previously unrecovered costs of the applicable pension benefits or the health and life benefits as approved in the District of Columbia through 2019.

Derivative and Weather Relate_3

Derivative and Weather Related Instruments (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Absolute Notional Amounts of Open Positions on Derivative Instruments	The following table presents absolute notional amounts of our derivative instruments as of September 30, 2019 and December 31, 2018 . Absolute Notional Amounts of Open Positions on Derivative Instruments Notional Amounts September 30, 2019 December 31, 2018 Natural Gas (In millions of therms) Asset optimization & trading 11,951.0 13,051.0 Other risk-management activities 950.0 1,072.0
Balance Sheet Classification of Derivative Instruments	The following table presents the balance sheet classification for all derivative instruments as of September 30, 2019 and December 31, 2018 . Balance Sheet Classification of Derivative Instruments (b) (in millions) Gross Gross Total (a) As of September 30, 2019 Current Assets—Derivatives $ 3.0 $ 0.6 $ 3.6 Deferred Charges and Other Assets—Derivatives 8.5 — 8.5 Current Liabilities—Derivatives 0.1 (12.9 ) (12.8 ) Deferred Credits—Derivatives — (105.1 ) (105.1 ) Total $ 11.6 $ (117.4 ) $ (105.8 ) As of December 31, 2018 Current Assets—Derivatives $ 25.7 $ (6.2 ) $ 19.5 Deferred Charges and Other Assets—Derivatives 11.3 — 11.3 Current Liabilities—Derivatives 1.1 (21.4 ) (20.3 ) Deferred Credits—Derivatives — (116.8 ) (116.8 ) Total $ 38.1 $ (144.4 ) $ (106.3 ) (a) Washington Gas has elected to offset the fair value of recognized derivative instruments against the right to reclaim or the obligation to return collateral for derivative instruments executed under the same master netting arrangement in accordance with ASC Topic 815. All recognized derivative contracts and associated financial collateral subject to a master netting arrangement or similar that is eligible for offset under ASC Topic 815 have been presented net in the balance sheet. (b) Washington Gas did not have derivative instruments outstanding that were designated as hedging instruments at September 30, 2019 or December 31, 2018 .
Gains and (Losses) on Derivative Instruments	The following table presents all gains and losses associated with derivative instruments for the three and nine months ended September 30, 2019 and 2018 . Gains and (Losses) on Derivative Instruments (In millions) Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Recorded to income Utility cost of gas (5.8 ) 2.0 (0.1 ) 0.5 Recorded to regulatory assets Gas costs (9.6 ) 3.7 4.8 (1.8 ) Total $ (15.4 ) $ 5.7 $ 4.7 $ (1.3 )
Potential Collateral Requirements for Derivative Liabilities with Credit-Risk-Contingent Features	The following table shows the aggregate fair value of all derivative instruments with credit-related contingent features that are in a liability position, as well as the maximum amount of collateral that would be required if the most intrusive credit-risk-related contingent features underlying these agreements were triggered on September 30, 2019 and December 31, 2018 , respectively. Potential Collateral Requirements for Derivative Liabilities with Credit-Risk-Contingent Features (In millions) September 30, 2019 December 31, 2018 Derivative liabilities with credit-risk-contingent features $ — $ 1.1 Maximum potential collateral requirements — 1.0

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements Under the Fair Value Hierarchy	The following table sets forth financial instruments recorded at fair value as of September 30, 2019 and December 31, 2018 , respectively. A financial instrument’s classification within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy. Fair Value Measurements Under the Fair Value Hierarchy (In millions) Level 1 Level 2 Level 3 Total At September 30, 2019 Assets Natural gas related derivatives $ — $ 1.6 $ 10.0 $ 11.6 Total Assets $ — $ 1.6 $ 10.0 $ 11.6 Liabilities Natural gas related derivatives $ — $ (1.1 ) $ (116.3 ) $ (117.4 ) Total Liabilities $ — $ (1.1 ) $ (116.3 ) $ (117.4 ) At December 31, 2018 Assets Natural gas related derivatives $ — $ 9.8 $ 28.3 $ 38.1 Total Assets $ — $ 9.8 $ 28.3 $ 38.1 Liabilities Natural gas related derivatives $ — $ (9.5 ) $ (134.9 ) $ (144.4 ) Total Liabilities $ — $ (9.5 ) $ (134.9 ) $ (144.4 )
Quantitative Information about Level 3 Fair Value Measurements	The following table includes quantitative information about the significant unobservable inputs used in the fair value measurement of our Level 3 financial instruments and the respective fair values of the net derivative asset and liability positions, by contract type, as of September 30, 2019 and December 31, 2018 . Quantitative Information about Level 3 Fair Value Measurements (In millions) Net Fair Value Valuation Techniques Unobservable Inputs Range Natural gas related derivatives ($106.3) Discounted Cash Flow Natural Gas Basis Price (per dekatherm) ($1.095) - $3.473 Net Fair Value Natural gas related derivatives ($106.6) Discounted Cash Flow Natural Gas Basis Price ($1.028)-$5.34
Reconciliation of Fair Value Measurements Using Significant Level 3 Inputs	The following table presents a summary of the changes in the fair value of our derivative instruments that are measured at net fair value on a recurring basis in accordance with ASC Topic 820 using significant Level 3 inputs during the three and nine months ended September 30, 2019 and 2018, respectively. Reconciliation of Fair Value Measurements Using Significant Level 3 Inputs (In millions) Total - Natural Gas Three Months Ended September 30, 2019 Balance at July 1, 2019 $ (86.9 ) Realized and unrealized gains (losses) Recorded to income (6.2 ) Recorded to regulatory assets—gas costs (10.1 ) Transfers into Level 3 (2.9 ) Transfers out of Level 3 2.9 Purchases — Sales — Settlements (3.1 ) Balance at September 30, 2019 $ (106.3 ) Three Months Ended September 30, 2018 Balance at July 1, 2018 $ (103.6 ) Realized and unrealized gains (losses) Recorded to income 3.5 Recorded to regulatory assets—gas costs 5.6 Transfers into Level 3 (0.1 ) Transfers out of Level 3 (0.1 ) Purchases — Settlements 0.6 Balance at September 30, 2018 $ (94.1 ) Nine Months Ended September 30, 2019 Balance at January 1, 2019 $ (106.6 ) Realized and unrealized gains (losses) Recorded to income (1.4 ) Recorded to regulatory assets—gas costs 4.3 Transfers into Level 3 (6.7 ) Transfers out of Level 3 7.9 Purchases — Settlements (3.8 ) Balance at September 30, 2019 $ (106.3 ) Nine Months Ended September 30, 2018 Balance at January 1, 2018 $ (125.4 ) Realized and unrealized gains (losses) Recorded to income (0.7 ) Recorded to regulatory assets—gas costs (3.1 ) Transfers into Level 3 (7.1 ) Transfers out of Level 3 8.9 Settlements 33.3 Balance at September 30, 2018 $ (94.1 )
Realized and Unrealized Gains (Losses) Recorded to Income for Level 3 Measurements	The table below sets forth the line items on the statements of operations to which amounts are recorded for the three and nine months ended September 30, 2019 and 2018, respectively, related to fair value measurements using significant Level 3 inputs. Realized and Unrealized Gains (Losses) Recorded to Income for Level 3 Measurements (In millions) Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Utility cost of gas $(6.2) $3.5 $(1.4) $(0.7)
Unrealized Gains (Losses) Recorded for Level 3 Measurements	Unrealized gains (losses) attributable to derivative assets and liabilities measured using significant Level 3 inputs were recorded as follows for the three and nine months ended September 30, 2019 and 2018, respectively. Unrealized Gains (Losses) Recorded for Level 3 Measurements (In millions) Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Recorded to income Utility cost of gas $ (5.9 ) $ 3.1 $ 1.6 $ 6.9 Recorded to regulatory assets—gas costs (10.2 ) 4.8 7.9 7.7 Total $ (16.1 ) $ 7.9 $ 9.5 $ 14.6
Fair Value of Financial Instruments	The following table presents the carrying amounts recorded at amortized cost and estimated fair values of our financial instruments at September 30, 2019 and December 31, 2018 . Fair Value of Financial Instruments September 30, 2019 December 31, 2018 (In millions) Carrying Amount Fair Value Carrying Amount Fair Value Money market funds (a) $ 48.7 $ 48.7 $ 69.7 $ 69.7 Commercial paper (b) $ 117.0 $ 117.0 $ 296.0 $ 296.0 Project financing (b) $ — $ — $ 15.5 $ 15.5 Current maturities of long-term debt $ 50.0 $ 50.0 $ 50.0 $ 50.0 Long-term debt (c) $ 1,331.1 $ 1,501.5 $ 1,035.0 $ 1,096.3 (a) The balance as of September 30, 2019 includes $0.6 million money market funds located in “Cash and cash equivalents,” $4.2 million rabbi trust investment located in “Current Assets-Other,” and $43.9 million rabbi trust investments located in “Deferred Charges and Other Assets-Other” of the accompanying balance sheet; The balance as of December 31, 2018 includes $4.4 million money market funds located in “Cash and cash equivalents,” $ 20.2 million rabbi trust investment located in “Current Assets-Other” and $45.1 million rabbi trust investments located in “Deferred Charges and Other Assets-Other.” The amounts in cash and cash equivalent may be offset by outstanding checks. (b) Balance is located in “Notes payable and project financing” in the accompanying balance sheet. (c) Includes adjustments for current maturities and unamortized discounts, as applicable.

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Gas Balancing Service Charges	The following table shows the amounts Washington Gas charged WGL Energy Services for balancing services. Gas Balancing Service Charges Three Months Ended Nine Months Ended (In millions) 2019 2018 2019 2018 Gas balancing service charge $ 2.9 $ 3.2 $ 14.9 $ 16.0

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table shows the changes in accumulated other comprehensive income (loss) by component for three and nine months ended September 30, 2019 and 2018 . Changes in Accumulated Other Comprehensive Income (Loss) by Component Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2019 2018 2019 2018 Beginning Balance $ (6,141 ) $ (3,959 ) $ (6,627 ) $ (4,330 ) Amortization of prior service cost (a)(b) (163 ) 145 (486 ) (401 ) Amortization of actuarial gain (loss) (a)(b) 392 112 1,198 1,172 Actuarial gain (loss) arising during the period (a) — 4,625 1,250 4,625 Current-period other comprehensive income (loss) 229 4,882 1,962 5,396 Income tax expense (benefit) related to pension and other post-retirement benefit plans (713 ) 2,753 534 2,896 Ending Balance $ (5,199 ) $ (1,830 ) $ (5,199 ) $ (1,830 ) (a) These accumulated other comprehensive income (loss) components are included in the computation of net periodic benefit cost. Refer to Note 9—Pension and other post-retirement benefit plans for additional details. (b) Amortization of prior service cost and amortization of actuarial gain (loss) represent the amounts reclassified out of AOCI to “Other income (expense)” of Statements of Operations for the reporting periods.

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2019
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information Table	The following table details the changes in operating assets and liabilities from operating activities, cash payments that have been included in the determination of earnings and non-cash investing and financing activities. Nine Months Ended September 30, Nine Months Ended September 30, (In thousands) 2019 2018 CHANGES IN OPERATING ASSETS AND LIABILITIES Accounts receivable and unbilled revenues $ 174,986 $ 159,066 Receivables from associated companies (3,981 ) 24,783 Gas costs and other regulatory assets/liabilities—net (8,253 ) (10,509 ) Storage gas 11,479 (16,419 ) Prepaid taxes (3,791 ) 14,167 Accounts payable and other accrued liabilities (109,287 ) 15,722 Payables to associated companies 10,383 (86,049 ) Customer deposits and advance payments (11,511 ) 28,947 Accrued taxes 6,830 (19,527 ) Other current assets 5,077 (4,701 ) Other current liabilities (240 ) 278 Deferred gas costs—net 49,379 17,717 Deferred assets—other 11,807 11,754 Deferred liabilities—other (26,879 ) (22,038 ) Pension and other post-retirement benefits (11,427 ) (14,079 ) Other—net — (798 ) Changes in operating assets and liabilities $ 94,572 $ 98,314 SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION Income taxes paid (refunded)—net $ 5,253 $ (2,025 ) Interest paid $ 54,238 $ 54,059 SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES: Extinguishment of project debt financing $ (15,460 ) $ (28,312 ) Capital expenditure accruals included in accounts payable and other accrued liabilities $ 39,976 $ 53,367
Reconciliation of cash, cash equivalents and restricted cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within Washington Gas’ balance sheet that sums to the total of such amounts shown on the statements of cash flows. (in thousands) September 30, 2019 September 30, 2018 Cash and cash equivalents $ 1 $ 1 Restricted cash included in Current Assets-Other $ 4,225 $ 20,207 Restricted cash included in Deferred Charges and Other Assets-Other $ 43,945 $ 44,775 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 48,171 $ 64,983

Accounting Policies (Narrative)

Accounting Policies (Narrative) (Details) $ in Millions	Sep. 30, 2019USD ($)subsidiary	Jan. 01, 2019USD ($)
Lease liabilities	$ 60.3	$ 58.9
Right-of-use asset		43.2
Lease incentives and prepaid or deferred rent		$ 15.7
Washington Gas Resources
Number of Subsidiaries | subsidiary	4

Revenue from Contracts With C_4

Revenue from Contracts With Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Contract with Customer, Liability	$ 0		$ 0
Revenue from contracts with customers	116,400		890,500
Other sources of revenue	5,900		23,900
Total Operating Revenue	122,305	$ 139,041	914,442	$ 870,593
Gas and transportation sales | Gas sold and delivered
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	70,700		665,100
Gas and transportation sales | Gas delivered for others
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	33,400		186,800
Gas and transportation sales | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10,900		34,400
Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,400		4,200
Revenue from alternative revenue programs
Disaggregation of Revenue [Line Items]
Other sources of revenue	3,600		14,900
Leasing revenue
Disaggregation of Revenue [Line Items]
Other sources of revenue	200		500
Other
Disaggregation of Revenue [Line Items]
Other sources of revenue	2,100		8,500
Energy management services projects not complete
Disaggregation of Revenue [Line Items]
Receivables, Long-term Contracts or Programs	0		0
Unbilled revenue	$ 40,500		$ 40,500

Leases Narrative (Details)

Leases Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Right-of-use asset			$ 43,200
Lease incentives and prepaid or deferred rent			15,700
Current lease liability	$ 5,632	$ 5,632	2,800	$ 0
Non current lease liability	54,686	$ 54,686	$ 56,100	$ 0
Lessee, Operating Lease, Description		<div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Washington Gas has operating leases for our corporate headquarters and other corporate offices, communication tower space, and certain office equipment.</font></div></div>" id="sjs-C7">&lt;div style="font-family:Times New Roman;font-size:10pt;">&lt;div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;">&lt;font style="font-family:inherit;font-size:10pt;">Washington Gas has operating leases for our corporate headquarters and other corporate offices, communication tower space, and certain office equipment.&lt;/font>&lt;/div>&lt;/div>
Lessee, Operating Lease, Option to Terminate		<div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The leases generally have options to terminate with notice prior to the end of the lease term based on the contract terms.</font></div></div>" id="sjs-C8">&lt;div style="font-family:Times New Roman;font-size:10pt;">&lt;div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;">&lt;font style="font-family:inherit;font-size:10pt;">The leases generally have options to terminate with notice prior to the end of the lease term based on the contract terms.&lt;/font>&lt;/div>&lt;/div>
Lessee, Operating Lease, Option to Extend		<div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Some of the leases include options to extend the lease terms for 1 to 5 years with prior written notice or automatically renew if either party does not provide intent to terminate.</font></div></div><div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Some of the leases include options to extend the lease terms for 1 to 5 years with prior written notice or automatically renew if either party does not provide intent to terminate.</font></div></div>" id="sjs-C9">&lt;div style="font-family:Times New Roman;font-size:10pt;">&lt;div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;">&lt;font style="font-family:inherit;font-size:10pt;">Some of the leases include options to extend the lease terms for 1 to 5 years with prior written notice or automatically renew if either party does not provide intent to terminate.&lt;/font>&lt;/div>&lt;/div>&lt;div style="font-family:Times New Roman;font-size:10pt;">&lt;div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;">&lt;font style="font-family:inherit;font-size:10pt;">Some of the leases include options to extend the lease terms for 1 to 5 years with prior written notice or automatically renew if either party does not provide intent to terminate.&lt;/font>&lt;/div>&lt;/div>
Lessor, Operating Lease, Option to Extend		<div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Some of the leases include options to extend the lease terms for 1 to 5 years with prior written notice or automatically renew if the lessee does not provide intent not to renew.</font></div></div>" id="sjs-C10">&lt;div style="font-family:Times New Roman;font-size:10pt;">&lt;div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;">&lt;font style="font-family:inherit;font-size:10pt;">Some of the leases include options to extend the lease terms for 1 to 5 years with prior written notice or automatically renew if the lessee does not provide intent not to renew.&lt;/font>&lt;/div>&lt;/div>
Lessor, Operating Lease, Option to Terminate		<div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The leases generally have options to terminate the leases with notice prior to the end of the lease term based on the contract terms.</font></div></div>" id="sjs-C11">&lt;div style="font-family:Times New Roman;font-size:10pt;">&lt;div style="line-height:120%;padding-top:6px;text-indent:12px;font-size:10pt;">&lt;font style="font-family:inherit;font-size:10pt;">The leases generally have options to terminate the leases with notice prior to the end of the lease term based on the contract terms.&lt;/font>&lt;/div>&lt;/div>
Operating Lease, Impairment Loss	$ 0	$ 0
Lease, Cost [Abstract]
Weighted average remaining lease term	13 years 6 months	13 years 6 months
Weighted average discount rate	3.32%	3.32%
Minimum
Lessee, Operating Lease, Remaining Lease Term	1 year	1 year
Lessor, Operating Lease, Remaining Lease Term	5 months	5 months
Maximum
Lessee, Operating Lease, Remaining Lease Term	22 years	22 years
Lessor, Operating Lease, Remaining Lease Term	82 years	82 years

Maturity of Operating Lease Lia

Maturity of Operating Lease Liabilities (Lessee) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
Operating Lease Liabilities, Payment Due [Abstract]
2019	$ 1.3
2020	5.9
2021	5.5
2022	5.5
2023	5.5
Thereafter	52.1
Total lease payments	75.8
Less: Interest	(15.5)
Present Value of Lease Liabilities	$ 60.3	$ 58.9

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information Related to Operating Leases (Lessee) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Cash paid for amounts included in the lease liabilities in the operating cash flows	$ 0.5	$ 1.5
Operating lease cost (including variable lease costs of $0.5 million and $1.5 million for the three and nine months ended September 30, 2019, respectively)	1.8	5.4
Variable lease cost	0.5	1.5
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 0.4	$ 1.5

Maturity of Operating Lease Pay

Maturity of Operating Lease Payments (Lessor) (Details) $ in Millions	Sep. 30, 2019USD ($)
Maturity of Operating Lease Payments [Abstract]
2019	$ 0.2
2020	0.7
2021	0.6
2022	0.6
2023	0.6
Thereafter	58.3
Total lease payments	$ 61

Accounts Payable and Other Ac_3

Accounts Payable and Other Accrued Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Accounts Payable and Accrued Liabilities [Abstract]
Accounts payable—trade	$ 139.4	$ 228.9
Employee benefits and payroll accruals	16.5	28
Other accrued liabilities	26.9	31.5
Total	$ 182.8	$ 288.4

Short-Term Debt (Details)

Short-Term Debt (Details) - USD ($)	3 Months Ended
	Sep. 30, 2019	Jul. 19, 2019	Dec. 31, 2018
Short Term Debt [Line Items]
Unsecured revolving credit facility		$ 450,000,000	$ 350,000,000
Revolving credit facility additional borrowings		100,000,000
Revolving credit facility maximum borrowing capacity		$ 550,000,000
Payables to associated companies	$ 68,066,000		95,228,000
Notes payable and project financing	$ 0
Minimum
Short Term Debt [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.06%
Maximum
Short Term Debt [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.175%
WGL Energy Services
Short Term Debt [Line Items]
Payables to associated companies	$ 2,100,000		53,000,000
Energy management services projects not complete
Short Term Debt [Line Items]
Unbilled revenue	40,500,000
Unbilled revenues	0
Energy management services projects not complete | WGL Energy Systems
Short Term Debt [Line Items]
Payables to associated companies	40,500,000		69,700,000
Notes payable and project financing			15,500,000
Unbilled revenues			85,300,000
Government agency with minimal credit risk [Member]
Short Term Debt [Line Items]
Reserve for bad debt	0		0
Committed credit
Short Term Debt [Line Items]
Unsecured revolving credit facility	450,000,000		350,000,000
Less: Commercial paper outstanding	(117,000,000)		(296,000,000)
Net committed credit available	$ 333,000,000		$ 54,000,000
Weighted average interest rate	2.31%		2.93%
Outstanding bank loans	$ 0		$ 0
Revolving credit facility additional borrowings	100,000,000
Revolving credit facility maximum borrowing capacity	$ 450,000,000

Long Term Debt (Details)

Long Term Debt (Details) - USD ($)	Sep. 30, 2019	Sep. 13, 2019	Dec. 31, 2018	Sep. 30, 2018
Long Term Debt [LIne Items]
Long-Term Debt	$ 1,396,000,000		$ 1,096,000,000
Unamortized discount	(4,300,000)		(2,900,000)
Unamortized debt expense	(10,600,000)		(8,100,000)
Less-current maturities	50,000,000		50,000,000
Total Long term debt	$ 1,331,100,000		$ 1,035,000,000
Weighted Average Interest Rate	4.53%		4.77%
Long-term debt principle		$ 300,000,000
Fixed interest rate		3.65%
Issuances
Long Term Debt [LIne Items]
Long-Term Debt	$ 300,000,000			$ 0
Long-term debt principle	0
Retirements
Long Term Debt [LIne Items]
Long-Term Debt	$ 0			$ 0

Components of Total Equity (Det

Components of Total Equity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shareholders' equity, beginning balance			$ 1,562,573
NET INCOME (LOSS)	$ (65,799)	$ (181,153)	26,606	$ (84,568)
OTHER COMPREHENSIVE INCOME (LOSS)	942	$ 2,129	1,428	2,500
Capital contribution from parent			0	$ 302,728
Common shareholders' equity, ending balance	$ 1,539,947		$ 1,539,947
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance, shares	46,479,536	46,479,536	46,479,536	46,479,536
Common shareholders' equity, beginning balance	$ 46,479	$ 46,479	$ 46,479	$ 46,479
Ending Balance, shares	46,479,536	46,479,536	46,479,536	46,479,536
Common shareholders' equity, ending balance	$ 46,479	$ 46,479	$ 46,479	$ 46,479
Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shareholders' equity, beginning balance	979,273	585,562	979,273	583,185
Stock-based compensation		(9,017)		(6,640)
Capital contribution from parent		302,728		302,728
Common shareholders' equity, ending balance	979,273	879,273	979,273	879,273
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shareholders' equity, beginning balance	585,193	723,749	543,448	670,580
NET INCOME (LOSS)	(65,799)	(181,153)	26,606	(84,568)
ASU 2018-02 adoption impact		1,484		1,484
Dividends declared - Common Stock		(24,908)	(50,000)	(67,664)
Dividends declared - Preferred Stock		(330)	(660)	(990)
Common shareholders' equity, ending balance	519,394	518,842	519,394	518,842
Retained Earnings		(1,500)		(1,500)
Accumulated Other Comprehensive Income (Loss), Net of Taxes
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shareholders' equity, beginning balance	(6,141)	(3,959)	(6,627)	(4,330)
OTHER COMPREHENSIVE INCOME (LOSS)	942	3,613	1,428	3,984
ASU 2018-02 adoption impact		(1,484)		(1,484)
Common shareholders' equity, ending balance	(5,199)	(1,830)	(5,199)	(1,830)
Total Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shareholders' equity, beginning balance	1,604,804	1,351,831	1,562,573	1,295,914
NET INCOME (LOSS)	(65,799)	(181,153)	26,606	(84,568)
OTHER COMPREHENSIVE INCOME (LOSS)	942	3,613	1,428	3,984
Stock-based compensation		(9,017)		(6,640)
Capital contribution from parent		302,728		302,728
Dividends declared - Common Stock		(24,908)	(50,000)	(67,664)
Dividends declared - Preferred Stock		(330)	(660)	(990)
Common shareholders' equity, ending balance	$ 1,539,947	$ 1,442,764	$ 1,539,947	$ 1,442,764

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Tax sharing - amount paid to other associated companies	$ 0	$ 0	$ 0	$ 0
Tax sharing - amount received from associated companies	0	0	0	0
Interest or penalties associated with uncertain tax position	$ 0	$ 0	$ 0	$ 0

Pension and Other Post-retire_3

Pension and Other Post-retirement Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Restricted cash included in Current Assets-Other	$ 4,378		$ 4,378		$ 20,347
Restricted cash included in Deferred Charges and Other Assets-Other	50,098		50,098		50,490
Reclass to Other income	3,533	$ (10,408)	7,298	$ (8,621)
ASU 2017-07
Defined Benefit Plan Disclosure [Line Items]
Reclass to Other income		$ 2,800		$ 8,400
Rabbi Trusts
Defined Benefit Plan Disclosure [Line Items]
Restricted Cash - Rabbi Trust Balance	43,800		43,800		60,800
Restricted cash included in Current Assets-Other	4,200		4,200		20,200
Restricted cash included in Deferred Charges and Other Assets-Other	$ 39,600		$ 39,600		$ 40,600

Pension and Other Post-retire_4

Pension and Other Post-retirement Benefit Plans (Components of Net Periodic Benefit Cost Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Recognized prior service cost (credit)	$ 163	$ (145)	$ 486	$ 401
Recognized actuarial loss	(392)	(4,737)	(2,448)	(5,797)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	3,000	3,700	9,100	11,100
Interest cost	10,200	9,900	30,700	29,700
Expected return on plan assets	(10,700)	(10,600)	(32,100)	(31,700)
Recognized prior service cost (credit)	100	100	300	300
Recognized actuarial loss	1,300	3,900	4,000	11,700
Settlement charge			4,300
Net periodic benefit cost (income)	3,900	7,000	16,300	21,100
Allocation to affiliates	(400)	(900)	(1,300)	(2,600)
Adjusted net periodic benefit cost (income)	3,500	6,100	15,000	18,500
Amount allocated to construction projects	(400)	(1,000)	(1,200)	(3,600)
Amount deferred as regulatory asset (liability)-net allocations		1,700	700	4,700
Amount charged (credited) to expense	3,100	6,800	14,500	19,600
Health and Life Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,300	1,300	3,800	3,900
Interest cost	3,000	2,900	9,000	8,700
Expected return on plan assets	(6,100)	(5,900)	(18,300)	(17,700)
Recognized prior service cost (credit)	(3,900)	(4,400)	(11,700)	(13,200)
Net periodic benefit cost (income)	(5,700)	(6,100)	(17,200)	(18,300)
Allocation to affiliates	500	700	1,800	2,100
Adjusted net periodic benefit cost (income)	(5,200)	(5,400)	(15,400)	(16,200)
Amount allocated to construction projects	(200)	800	(600)	2,900
Amount charged (credited) to expense	$ (5,400)	$ (4,600)	$ (16,000)	$ (13,300)

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details) - USD ($)	Sep. 16, 2019	Jun. 21, 2019	Apr. 12, 2019	Jul. 31, 2018	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2017
Commitments and Contingencies [Line Items]
Reduction in Operating Revenue					$ 122,305,000		$ 139,041,000	$ 914,442,000	$ 870,593,000
Reduction in Income Tax Expense (Benefit)					(19,293,000)		(69,121,000)	4,992,000	(50,717,000)
Regulatory Asset					82,116,000	$ 99,105,000		82,116,000		$ 82,116,000
Deferred Gas Cost					91,913,000	141,636,000		91,913,000		91,913,000
Operation and Maintenance Expenses					101,195,000		282,793,000	300,433,000	461,808,000
Utility cost of gas					33,433,000		$ 20,939,000	$ 331,285,000	$ 282,298,000
Virginia rate case
Commitments and Contingencies [Line Items]
Requested base rate increase				$ 37,600,000
Recommended Return on Equity, percentage	9.20%
Public Utilities, Approved Return on Equity, Percentage								9.50%
Reduction in Operating Revenue	$ 7,600,000
Reduction in Income Tax Expense (Benefit)	11,800,000
Public Utilities Recommended Rate Increase Decrease Amount	0
Regulatory Asset	7,100,000
Operation and Maintenance Expenses	2,000,000
Virginia rate case | Asset Impairment for Regulatory Action
Commitments and Contingencies [Line Items]
Regulatory Asset	5,500,000
Virginia rate case | Minimum
Commitments and Contingencies [Line Items]
Requested Return on Equity, Percentage			10.30%
Requested Overall Rate of Return, Percentage			7.81%
Virginia rate case | Maximum
Commitments and Contingencies [Line Items]
Requested Return on Equity, Percentage			10.60%
Requested Overall Rate of Return, Percentage			7.94%
Accelerated pipeline replacement program
Commitments and Contingencies [Line Items]
Requested base rate increase				$ 14,700,000
Tax cuts and jobs act
Commitments and Contingencies [Line Items]
Regulatory liability	35,400,000				18,900,000			$ 18,900,000		18,900,000		$ 5,600,000
Reduction in Operating Revenue	$ 13,300,000
Tax cuts and jobs act | Virginia
Commitments and Contingencies [Line Items]
Regulatory liability					0	35,400,000		0		0
Environmental matters
Commitments and Contingencies [Line Items]
Liability for future environmental response costs					10,700,000	11,300,000		10,700,000		10,700,000
Estimated maximum liability for all environmental sites					35,800,000	29,400,000
Regulatory Asset					6,300,000	5,800,000		6,300,000		6,300,000
Antero contract
Commitments and Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value		$ 95,900,000
Antero contract | Washington Gas
Commitments and Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value		11,200,000
Loss Contingency Accrual					11,200,000			11,200,000		11,200,000	$ 2,600,000
Loss Contingency, Receivable					1,300,000			1,300,000		1,300,000
Loss Contingency, Loss in Period										3,000,000
Deferred Gas Cost					4,500,000			4,500,000		4,500,000
Operation and Maintenance Expenses					100,000
Utility cost of gas					2,800,000
Antero contract | WGL Midstream
Commitments and Contingencies [Line Items]
Loss Contingency, Damages Awarded, Value		$ 84,700,000
Antero contract - court costs
Commitments and Contingencies [Line Items]
Loss Contingency Accrual					100,000			100,000		100,000
Merger commitments
Commitments and Contingencies [Line Items]
Other commitments amounts paid in prior fiscal year					118,700,000
Other commitments amounts paid in current fiscal year					1,100,000			7,600,000
Operation and Maintenance Expenses					136,600,000
Merger commitments | Natural gas extension
Commitments and Contingencies [Line Items]
Operation and Maintenance Expenses					70,000,000
Merger commitments | Natural gas extension | Maryland
Commitments and Contingencies [Line Items]
Operation and Maintenance Expenses					3,900,000
Merger commitments | Future hiring
Commitments and Contingencies [Line Items]
Operation and Maintenance Expenses					2,400,000
Merger commitments | Future leak mitigation
Commitments and Contingencies [Line Items]
Operation and Maintenance Expenses					7,500,000
Other External Partners | Performance Guarantee [Member]
Commitments and Contingencies [Line Items]
Unrecorded Unconditional Purchase Obligation					$ 0	$ 0		$ 0		$ 0

Derivative and Weather Relate_4

Derivative and Weather Related Instruments Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)Counterparties	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)Counterparties	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Liability, Fair Value, Gross Liability	$ (117.4)		$ (117.4)		$ (144.4)
Asset Optimization [Abstract]
Gain (Loss) on Asset Optimization Transactions Net Pretax	1.2	$ (7.7)	(8.3)	$ (28.5)
Unrealized Gains (Loss) On Asset Optimization Derivative Instruments Net Pretax	(6.5)	$ 3.3	0.1	$ 11.8
Asset optimization loss contingency related			3
Derivative, Collateral [Abstract]
Right to Reclaim Cash	3.3		3.3		7.4
Derivative, Collateral, Obligation to Return Cash	$ 0.1		$ 0.1		$ 0.2
Concentration of Credit Risk [Abstract]
Number of Counterparties | Counterparties	2		2
Percentage Of Credit Exposure	10.00%		10.00%
Obligation to counterparties	$ 14.6		$ 14.6

Derivative and Weather Relate_5

Derivative and Weather Related Instruments (Gains and Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Gains and (Losses) on Derivative Instruments
Total	$ (15,400)	$ 5,700	$ 4,700	$ (1,300)
Interest Expense	15,575	14,404	45,092	43,531
Utility cost of gas
Gains and (Losses) on Derivative Instruments
Recorded to income	(5,800)	2,000	(100)	500
Gas costs
Gains and (Losses) on Derivative Instruments
Recorded to regulatory assets	$ (9,600)	$ 3,700	$ 4,800	$ (1,800)

Potential Collateral Requiremen

Potential Collateral Requirements for Derivative Liabilities with Credit-Risk-Contingent Features (Details) - Credit Risk Contract - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative liabilities with credit-risk-contingent features	$ 0	$ 1.1
Maximum potential collateral requirements	$ 0	$ 1

Absolute Notional Amounts of Op

Absolute Notional Amounts of Open Positions on Derivative Instruments (Details) - MMBTU MMBTU in Millions	Sep. 30, 2019	Dec. 31, 2018
Asset Optimization [Member]
Derivative [Line Items]
Natural Gas Derivative Transaction, Volume	1,195,100,000	1,305,100,000
Other risk-management activities
Derivative [Line Items]
Natural Gas Derivative Transaction, Volume	95,000,000	107,200,000

Balance Sheet Classification of

Balance Sheet Classification of Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Gross Derivative Assets	$ 11.6	$ 38.1
Gross Derivative Liabilities	(117.4)	(144.4)
Total	(105.8)	(106.3)
Current Assets—Derivatives
Derivative [Line Items]
Gross Derivative Assets	3	25.7
Gross Derivative Liabilities	(0.6)	(6.2)
Total	3.6	19.5
Deferred Charges and Other Assets—Derivatives
Derivative [Line Items]
Gross Derivative Assets	8.5	11.3
Total	8.5	11.3
Current Liabilities—Derivatives
Derivative [Line Items]
Gross Derivative Assets	0.1	1.1
Gross Derivative Liabilities	12.9	(21.4)
Total	(12.8)	(20.3)
Deferred Credits—Derivatives
Derivative [Line Items]
Gross Derivative Assets	0
Gross Derivative Liabilities	105.1	(116.8)
Total	$ (105.1)	$ (116.8)

Fair Value Measurements Under t

Fair Value Measurements Under the Fair Value Hierarchy (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Assets	$ 11.6	$ 38.1
Liabilities	(117.4)	(144.4)
Natural Gas Related Derivatives
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Assets	11.6	38.1
Liabilities	(117.4)	(144.4)
Level 2
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Assets	1.6	9.8
Liabilities	(1.1)	(9.5)
Level 2 | Natural Gas Related Derivatives
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Assets	1.6	9.8
Liabilities	(1.1)	(9.5)
Level 3
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Assets	10	28.3
Liabilities	(116.3)	(134.9)
Level 3 | Natural Gas Related Derivatives
Fair Value Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Assets	10	28.3
Liabilities	$ (116.3)	$ (134.9)

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative information) (Details) - Natural Gas Related Derivatives $ in Millions	3 Months Ended
	Dec. 31, 2018USD ($)$ / dekatherm	Sep. 30, 2018USD ($)$ / dekatherm	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Fair Value Measurements Details [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs | $	$ (106.6)	$ (94.1)	$ (106.3)	$ (86.9)	$ (103.6)	$ (125.4)
Discounted Cash Flow
Fair Value Measurements Details [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs | $	$ (106.6)		$ (106.3)
Discounted Cash Flow | Maximum | Natural Gas Basis Price
Fair Value Measurements Details [Line Items]
Input price | $ / dekatherm	5.34	3.473
Discounted Cash Flow | Minimum | Natural Gas Basis Price
Fair Value Measurements Details [Line Items]
Input price | $ / dekatherm	1.028	1.095

Fair Value Measurements (Reconc

Fair Value Measurements (Reconciliation with Level 3 Inputs) (Details) - Natural Gas Related Derivatives - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reconciliation of Fair Value Measurements Using Significant Level 3 Inputs
Beginning Balance	$ (86.9)	$ (103.6)	$ (106.6)	$ (125.4)
Recorded to Income	(6.2)	3.5	(1.4)	(0.7)
Recorded to regulatory assets - gas costs	(10.1)	5.6	4.3	(3.1)
Transfers into Level 3	(2.9)	(0.1)	(6.7)	(7.1)
Transfers out of Level 3	2.9	(0.1)	7.9	8.9
Settlements	(3.1)	0.6	(3.8)	33.3
Ending Balance	$ (106.3)	$ (94.1)	$ (106.3)	$ (94.1)

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value of Financial Instruments) (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Project financing	$ 0
Current maturities of long-term debt	50,000,000	$ 50,000,000
Long term debt	1,331,100,000	1,035,000,000
Restricted cash included in Current Assets-Other	4,378,000	20,347,000
Restricted cash included in Deferred Charges and Other Assets-Other	50,098,000	50,490,000
Cash and Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Money Market Funds	600,000	4,400,000
Rabbi Trusts
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Restricted cash included in Current Assets-Other	4,225,000	20,207,000	$ 20,207,000
Restricted cash included in Deferred Charges and Other Assets-Other	43,945,000	45,100,000	$ 44,775,000
Carrying Amount
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Money Market Funds	48,700,000	69,700,000
Commercial Paper	117,000,000	296,000,000
Project financing	0	15,500,000
Current maturities of long-term debt	50,000,000	50,000,000
Long term debt	1,331,100,000	1,035,000,000
Fair Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Money Market Funds	48,700,000	69,700,000
Commercial Paper	117,000,000	296,000,000
Project financing	0	15,500,000
Current maturities of long-term debt	50,000,000	50,000,000
Long-term debt	$ 1,501,500,000	$ 1,096,300,000

Fair Value Measurements (Realiz

Fair Value Measurements (Realized and Unrealized Gains and Losses with Level 3 Measurements) (Details) - Natural Gas Related Derivatives - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Unrealized Gains (Losses) Recorded for Level 3 Measurements
Recorded to regulatory assets - gas costs	$ (10.1)	$ 5.6	$ 4.3	$ (3.1)
Total Unrealized Gains (Losses)	(16.1)	7.9	9.5	14.6
Utility cost of gas
Realized and Unrealized Gains (Losses) Recorded to Income for Level 3 Measurements
Recorded to income	(6.2)	3.5	(1.4)	(0.7)
Unrealized Gains (Losses) Recorded for Level 3 Measurements
Recorded to income	(5.9)	3.1	1.6	6.9
Regulatory asset-gas costs member
Unrealized Gains (Losses) Recorded for Level 3 Measurements
Recorded to regulatory assets - gas costs	$ (10.2)	$ 4.8	$ 7.9	$ 7.7

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Payables to associated companies	$ 68,066		$ 68,066		$ 95,228
Receivables from Associated Companies	8,800		8,800		4,819
Operation and maintenance	101,195	$ 282,793	300,433	$ 461,808
Current liabilities-other	7,266		7,266		7,507
AltaGas | Shared service costs
Related Party Transaction [Line Items]
Payables to associated companies	15,900		15,900		0
Operation and maintenance	5,000		12,500
WGL Energy Services
Related Party Transaction [Line Items]
Payables to associated companies	2,100		2,100		53,000
Receivables from Associated Companies					700
Gas balancing service charge	2,900	3,200	14,900	16,000
Related Party Purchased Receivables	3,500		3,500		6,400
Other associated companies | Shared service costs
Related Party Transaction [Line Items]
Receivables from Associated Companies	3,400		3,400		$ 600
Hampshire Gas Company
Related Party Transaction [Line Items]
Operation and maintenance	$ 1,500	$ 1,900	$ 5,500	$ 5,300

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
AOCI, Net of Tax [Roll Forward]
Beginning Balance	$ (6,141)	$ (3,959)	$ (6,627)	$ (4,330)
Amortization of prior service cost	(163)	145	(486)	(401)
Amortization of actuarial gain (loss)	392	112	1,198	1,172
Actuarial gain (loss) arising during the period	0	4,625	1,250	4,625
Current-period other comprehensive income (loss)	229	4,882	1,962	5,396
Income tax expense (benefit) related to pension and other post-retirement benefit plans	(713)	2,753	534	2,896
Ending Balance	$ (5,199)	$ (1,830)	$ (5,199)	$ (1,830)

Supplemental Cash Flow Inform_4

Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Operating Capital [Abstract]
Accounts receivable and unbilled revenues	$ 174,986	$ 159,066
Receivables from associated companies	(3,981)	24,783
Gas costs and other regulatory assets/liabilities—net	(8,253)	(10,509)
Storage gas	11,479	(16,419)
Prepaid taxes	(3,791)	14,167
Accounts payable and other accrued liabilities	(109,287)	15,722
Payables to associated companies	10,383	(86,049)
Customer deposits and advance payments	(11,511)	28,947
Accrued taxes	6,830	(19,527)
Other current assets	5,077	(4,701)
Other current liabilities	(240)	278
Deferred gas costs—net	49,379	17,717
Deferred assets—other	11,807	11,754
Deferred liabilities—other	(26,879)	(22,038)
Pension and other post-retirement benefits	(11,427)	(14,079)
Other—net		(798)
Changes in operating assets and liabilities	(94,572)	(98,314)
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Income taxes paid (refunded)—net	5,253	(2,025)
Interest paid	54,238	54,059
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Extinguisment of project debt financing	(15,460)	(28,312)
Capital expenditure accruals included in accounts payable and other accrued liabilities	39,976	53,367
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	1	1	$ 6,082
Restricted cash included in Current Assets-Other	4,378		20,347
Restricted cash included in Deferred Charges and Other Assets-Other	50,098		50,490
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	48,171	64,983	71,423	$ 6,652
Rabbi Trusts
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Restricted cash included in Current Assets-Other	4,225	20,207	20,207
Restricted cash included in Deferred Charges and Other Assets-Other	$ 43,945	$ 44,775	$ 45,100