Regulatory Assets and Liabilities (Schedule of Regulatory Assets) (Detail) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
		Feb. 29, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Regulatory assets-current			$ 1,309.0	$ 1,883.0
Regulatory assets-noncurrent			8,356.0	8,265.0
Total regulatory assets			9,665.0	10,148.0
Impairment of assets and other charges			307.0	1,401.0	$ 194.0
Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-current			868.0	1,140.0
Regulatory assets-noncurrent			4,317.0	4,247.0
Total regulatory assets			$ 5,185.0	5,387.0
Virginia Electric and Power Company | Subsequent Event
Regulatory Assets [Line Items]
Estimated under-recovered balances		$ 1.3
Weighted Average
Regulatory Assets [Line Items]
Weighted average useful life			25 years
Weighted Average | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Weighted average useful life			24 years
SCANA
Regulatory Assets [Line Items]
Electric service customers over period			20 years
Impairment of assets and other charges					$ 100.0
Deferred cost of fuel used in electric generation
Regulatory Assets [Line Items]
Regulatory assets-current	[1]		$ 245.0	603.0
Regulatory assets-noncurrent	[1]		1,221.0	1,551.0
Deferred cost of fuel used in electric generation | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-current	[1]		95.0	133.0
Regulatory assets-noncurrent	[1]		1,221.0	1,551.0
Deferred rider costs for Virginia electric utility
Regulatory Assets [Line Items]
Regulatory assets-current	[2]		270.0	152.0
Regulatory assets-noncurrent	[2]		496.0	363.0
Deferred rider costs for Virginia electric utility | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-current	[2]		270.0	152.0
Regulatory assets-noncurrent	[2]		496.0	363.0
Impairment of assets and other charges after tax			27.0
Impairment of assets and other charges			36.0
Ash pond and landfill closure costs
Regulatory Assets [Line Items]
Regulatory assets-current	[3]		200.0	221.0
Regulatory assets-noncurrent	[3]		$ 2,410.0	2,051.0
Regulatory assets expected collection period commencing year			2021
Ash pond and landfill closure costs | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-current	[3]		$ 200.0	221.0
Regulatory assets-noncurrent	[3]		2,407.0	2,049.0
Deferred nuclear refueling outage costs
Regulatory Assets [Line Items]
Regulatory assets-current	[4]		63.0	83.0
Deferred nuclear refueling outage costs | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-current	[4]		63.0	83.0
NND Project Costs
Regulatory Assets [Line Items]
Regulatory assets-current	[5]		138.0	138.0
Regulatory assets-noncurrent	[5]		1,949.0	2,088.0
Deferred early plant retirement charges
Regulatory Assets [Line Items]
Regulatory assets-current	[6]		0.0	226.0
Deferred early plant retirement charges | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-current	[6]		0.0	226.0
Other
Regulatory Assets [Line Items]
Regulatory assets-current			231.0	204.0
Regulatory assets-noncurrent			590.0	518.0
Other | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-current			80.0	74.0
Regulatory assets-noncurrent			127.0	132.0
Derivatives
Regulatory Assets [Line Items]
Regulatory assets-current	[7]		162.0	256.0
Regulatory assets-noncurrent	[7]		107.0	254.0
Derivatives | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-current	[7]		160.0	251.0
Regulatory assets-noncurrent	[7]		66.0	148.0
Unrecognized Pension and Other Postretirement Benefit Costs
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[8]		1,036.0	891.0
Unrecognized Pension and Other Postretirement Benefit Costs | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[8]		0.0	4.0
Unrecognized Pension and Other Postretirement Benefit Costs | East Ohio, PSNC and Questar Gas
Regulatory Assets [Line Items]
Regulatory assets-noncurrent			$ 215.0	302.0
Ash pond and landfill closure costs | Minimum
Regulatory Assets [Line Items]
Regulatory assets amounts expected collection period			15 years
Ash pond and landfill closure costs | Maximum
Regulatory Assets [Line Items]
Regulatory assets amounts expected collection period			18 years
Interest rate hedges
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[9]		$ 168.0	169.0
Interest rate hedges | Virginia Electric and Power Company
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[9]		0.0	0.0
AROs and related funding
Regulatory Assets [Line Items]
Regulatory assets-noncurrent	[10]		$ 379.0	$ 380.0
Amortization period for deferred costs			105 years
Deferred Project Costs | Maximum
Regulatory Assets [Line Items]
Amortization period for deferred costs			18 months

[1] Reflects deferred fuel expenses for the Virginia and North Carolina jurisdictions of Virginia Power’s electric generation operations. Additionally, Dominion Energy includes deferred fuel expenses for the South Carolina jurisdiction of its electric generation operations. In February 2024, Virginia Power completed a securitization of $1.3 billion of under-recovered fuel costs for its Virginia service territory. See Notes 13 and 18 for additional information.

[2] Reflects deferrals under Virginia Power’s electric transmission FERC formula rate and the deferral of costs associated with certain current and prospective rider projects. In 2023, Virginia Power recorded a charge of $36 million ($27 million after-tax), included in impairment of assets and other charges in its Consolidated Statements of Income (reflected in the Corporate and Other segment), for the write-off of certain previously deferred amounts related to Riders R, S and W in connection with the cessation of such riders effective July 2023. See Note 13 for additional information.

[3] Primarily reflects legislation in Virginia which requires any CCR asset located at certain Virginia Power stations to be closed by removing the CCR to an approved landfill or through beneficial reuse. These deferred costs are expected to be collected over a period between 15 and 18 years commencing December 2021 through Rider CCR. Virginia Power is entitled to collect carrying costs on uncollected expenditures once expenditures have been made.

[4] Legislation in Virginia requires Virginia Power to defer operation and maintenance costs incurred in connection with the refueling of any nuclear-powered generating plant. These deferred costs will be amortized over the refueling cycle, not to exceed 18 months.

[5] Reflects expenditures by DESC associated with the NND Project, which pursuant to the SCANA Merger Approval Order, will be recovered from DESC electric service customers over a 20-year period ending in 2039.

[6] Reflects amounts from the early retirements of certain coal- and oil-fired generating units which were amortized through 2023 in accordance with the settlement of the 2021 Triennial Review. See Note 13 for additional information.

[7] Represents changes in the fair value of derivatives, excluding separately presented interest rate hedges, that following settlement are expected to be recovered from or refunded to customers.

[8] Represents unrecognized pension and other postretirement employee benefit costs expected to be recovered or refunded through future rates generally over the expected remaining service period of plan participants by certain of Dominion Energy’s rate-regulated subsidiaries. Includes regulatory assets of $215 million and $302 million and regulatory liabilities of $12 million and $6 million in aggregate at December 31, 2023 and 2022, respectively, related to retained pension and other postretirement benefit plan assets and obligations for the East Ohio, PSNC and Questar Gas Transactions which will be reclassified to AOCI upon closing of each transaction.

[9] Reflects interest rate hedges recoverable from or refundable to customers. Certain of these instruments are settled and any related payments are being amortized into interest expense over the life of the related debt, which has a weighted-average useful life of approximately 25 years and 24 years for Dominion Energy and Virginia Power, respectively, as of December 31, 2023.

[10] Represents uncollected costs, including deferred depreciation and accretion expense related to legal obligations associated with the future retirement of generation, transmission and distribution properties. The AROs primarily relate to DESC’s electric generating facilities, including Summer, and are expected to be recovered over the related property lives and periods of decommissioning which may range up to approximately 105 years.