Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Consolidation and Variable Interest Entities DESC has determined that it has a controlling financial interest in each of GENCO and Fuel Company (which are considered to be VIEs) and, accordingly, DESC's Consolidated Financial Statements include, after eliminating intercompany balances and transactions, the accounts of DESC, GENCO and Fuel Company. The equity interests in GENCO and Fuel Company are held solely by SCANA, DESC’s parent. As a result, GENCO and Fuel Company’s equity and results of operations are reflected as noncontrolling interest in the Consolidated Financial Statements. GENCO owns a coal-fired electric generating station with a 605 MW net generating capacity (summer rating). GENCO’s electricity is sold, pursuant to a FERC-approved tariff, solely to DESC under the terms of a power purchase agreement and related operating agreement. The effects of these transactions are eliminated in consolidation. GENCO’s property (carrying value of $501 million) previously served as collateral for its long-term borrowings. In May 2019, GENCO redeemed its 5.49% senior secured notes and was able to release the first mortgage lien in June 2019 that had previously secured these notes. Fuel Company acquires, owns and provides financing for DESC’s nuclear fuel, certain fossil fuels and emission and other environmental allowances. See also Note 5. Additionally, DESC purchases shared services from DESS, an affiliated VIE that provides accounting, legal, finance and certain administrative and technical services to all SCANA subsidiaries, including DESC. DESC has determined that it is not the primary beneficiary of DESS as it does not have either the power to direct the activities that most significantly impact its economic performance or an obligation to absorb losses and benefits which could be significant to it. See Note 14 for amounts attributable to affiliates. Significant Accounting Policies There have been no significant changes from Note 1 to the Consolidated Financial Statements in DESC's Annual Report on Form 10-K for the year ended December 31, 2018, with the exception of the item described below. Leases DESC leases certain assets including vehicles, real estate, office equipment and other assets under both operating and finance leases. For operating leases, rent expense is recognized on a straight-line basis over the term of the lease agreement, subject to regulatory framework. Rent expense associated with operating leases, short-term leases and variable leases is primarily recorded in other operations and maintenance expense in the Consolidated Statements of Comprehensive Income (Loss). Rent expense associated with finance leases results in the separate presentation of interest expense on the lease liability and amortization expense of the related right-of-use asset in the Consolidated Statements of Comprehensive Income (Loss). Amortization expense and interest charges associated with finance leases are recorded in depreciation and amortization and interest charges, respectively, in the Consolidated Statements of Comprehensive Income (Loss) or deferred within regulatory assets in the Consolidated Balance Sheets. Certain leases include one or more options to renew, with renewal terms that can extend the lease from one to 70 years. The exercise of renewal options is solely at DESC's discretion and is included in the lease term if the option is reasonably certain to be exercised. A right-of-use asset and corresponding lease liability for leases with original lease terms of one year or less are not included in the Consolidated Balance Sheets, unless such leases contain renewal options that DESC is reasonably certain will be exercised. The determination of the discount rate utilized has a significant impact on the calculation of the present value of the lease liability included in the Consolidated Balance Sheets. For DESC’s leased assets, the discount rate implicit in the lease is generally unable to be determined from a lessee perspective. As such, DESC uses internally-developed incremental borrowing rates as a discount rate in the calculation of the present value of the lease liability. The incremental borrowing rates are determined based on an analysis of DESC's publicly available secured borrowing rates over various lengths of time that most closely correspond to DESC's lease maturities. Recently Adopted Accounting Standards In February 2016, the Financial Accounting Standards Board issued revised accounting guidance for the recognition, measurement, presentation and disclosure of leasing arrangements. The update requires that a liability and corresponding right-of-use asset are recorded on the balance sheet for all leases, including those leases classified as operating leases, while also refining the definition of a lease. In addition, lessees will be required to disclose key information about the amount, timing, and uncertainty of cash flows arising from leasing arrangements. Lessor accounting remains largely unchanged. The guidance became effective for DESC's interim and annual reporting periods beginning January 1, 2019. DESC adopted this revised accounting guidance using a modified retrospective approach, which requires lessees and lessors to recognize and measure leases at the date of adoption. Under this approach, DESC utilized the transition practical expedient to maintain historical presentation for periods before January 1, 2019. DESC also applied the other practical expedients, which required no reassessment of whether existing contracts are or contain leases, no reassessment of lease classification for existing leases and no evaluation of existing or expired land easements that were not previously accounted for as leases. In connection with the adoption of this revised accounting guidance, DESC recorded $19 million of offsetting right-of-use assets and liabilities for operating leases in effect at the adoption date. See Note 12 for additional information.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2019

Summary of Significant Accounting Policies

1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Consolidation and Variable Interest Entities

DESC has determined that it has a controlling financial interest in each of GENCO and Fuel Company (which are considered to be VIEs) and, accordingly, DESC's Consolidated Financial Statements include, after eliminating intercompany balances and transactions, the accounts of DESC, GENCO and Fuel Company. The equity interests in GENCO and Fuel Company are held solely by SCANA, DESC’s parent. As a result, GENCO and Fuel Company’s equity and results of operations are reflected as noncontrolling interest in the Consolidated Financial Statements.

GENCO owns a coal-fired electric generating station with a 605 MW net generating capacity (summer rating). GENCO’s electricity is sold, pursuant to a FERC-approved tariff, solely to DESC under the terms of a power purchase agreement and related operating agreement. The effects of these transactions are eliminated in consolidation. GENCO’s property (carrying value of $501 million) previously served as collateral for its long-term borrowings. In May 2019, GENCO redeemed its 5.49% senior secured notes and was able to release the first mortgage lien in June 2019 that had previously secured these notes. Fuel Company acquires, owns and provides financing for DESC’s nuclear fuel, certain fossil fuels and emission and other environmental allowances. See also Note 5.

Additionally, DESC purchases shared services from DESS, an affiliated VIE that provides accounting, legal, finance and certain administrative and technical services to all SCANA subsidiaries, including DESC. DESC has determined that it is not the primary beneficiary of DESS as it does not have either the power to direct the activities that most significantly impact its economic performance or an obligation to absorb losses and benefits which could be significant to it. See Note 14 for amounts attributable to affiliates.

Significant Accounting Policies

There have been no significant changes from Note 1 to the Consolidated Financial Statements in DESC's Annual Report on Form 10-K for the year ended December 31, 2018, with the exception of the item described below.

Leases

DESC leases certain assets including vehicles, real estate, office equipment and other assets under both operating and finance leases. For operating leases, rent expense is recognized on a straight-line basis over the term of the lease agreement, subject to regulatory framework. Rent expense associated with operating leases, short-term leases and variable leases is primarily recorded in other operations and maintenance expense in the Consolidated Statements of Comprehensive Income (Loss). Rent expense associated with finance leases results in the separate presentation of interest expense on the lease liability and amortization expense of the related right-of-use asset in the Consolidated Statements of Comprehensive Income (Loss). Amortization expense and interest charges associated with finance leases are recorded in depreciation and amortization and interest charges, respectively, in the Consolidated Statements of Comprehensive Income (Loss) or deferred within regulatory assets in the Consolidated Balance Sheets.

Certain leases include one or more options to renew, with renewal terms that can extend the lease from one to 70 years. The exercise of renewal options is solely at DESC's discretion and is included in the lease term if the option is reasonably certain to be exercised. A right-of-use asset and corresponding lease liability for leases with original lease terms of one year or less are not included in the Consolidated Balance Sheets, unless such leases contain renewal options that DESC is reasonably certain will be exercised.

The determination of the discount rate utilized has a significant impact on the calculation of the present value of the lease liability included in the Consolidated Balance Sheets. For DESC’s leased assets, the discount rate implicit in the lease is generally unable to be determined from a lessee perspective. As such, DESC uses internally-developed incremental borrowing rates as a discount rate in the calculation of the present value of the lease liability. The incremental borrowing rates are determined based on an analysis of DESC's publicly available secured borrowing rates over various lengths of time that most closely correspond to DESC's lease maturities.

Recently Adopted Accounting Standards

In February 2016, the Financial Accounting Standards Board issued revised accounting guidance for the recognition, measurement, presentation and disclosure of leasing arrangements. The update requires that a liability and corresponding right-of-use asset are recorded on the balance sheet for all leases, including those leases classified as operating leases, while also refining the definition of a lease. In addition, lessees will be required to disclose key information about the amount, timing, and uncertainty of cash flows arising from leasing arrangements. Lessor accounting remains largely unchanged.

The guidance became effective for DESC's interim and annual reporting periods beginning January 1, 2019. DESC adopted this revised accounting guidance using a modified retrospective approach, which requires lessees and lessors to recognize and measure leases at the date of adoption. Under this approach, DESC utilized the transition practical expedient to maintain historical presentation for periods before January 1, 2019. DESC also applied the other practical expedients, which required no reassessment of whether existing contracts are or contain leases, no reassessment of lease classification for existing leases and no evaluation of existing or expired land easements that were not previously accounted for as leases. In connection with the adoption of this revised accounting guidance, DESC recorded $19 million of offsetting right-of-use assets and liabilities for operating leases in effect at the adoption date. See Note 12 for additional information.