Operating Segments - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2025	Jun. 30, 2024		Jun. 30, 2025	Jun. 30, 2024		Dec. 31, 2024
Segment Reporting Information [Line Items]
Operating Revenue	[1]	$ 832	$ 731		$ 1,818	$ 1,506
Fuel used in electric generation	[2]	155	135		359	280
Purchased power	[1],[2]	37	22		59	32
Gas purchased for resale	[2]	49	46		175	125
Other operations and maintenance	[2]	167	172	[3]	341	335	[3]
Depreciation and amortization	[2]	142	136		282	272
Other taxes	[1],[2]	77	76		159	154
Total operating expenses		627	587		1,375	1,198
Other income (expense), net	[4]	3	1		6	2
Interest charges, net of AFUDC	[2]	70	67		141	134
Income tax expense	[2]	31	15		51	33
Comprehensive Income Attributable to Noncontrolling Interest	[4]	6	6		14	12
Comprehensive Income (Loss) Available (Attributable) to Common Shareholder		101	57		243	131
Capital expenditures					561	490
Total assets		17,328			17,328			$ 17,041
Dominion Energy South Carolina, Inc. [Member]
Segment Reporting Information [Line Items]
Operating Revenue		832	731		1,818	1,506
Fuel used in electric generation	[2]	155	135		359	280
Purchased power	[2]	37	22		59	32
Gas purchased for resale	[2]	49	46		175	125
Other operations and maintenance	[2]	167	168	[3]	341	331	[3]
Depreciation and amortization	[2]	142	136		282	272
Other taxes	[2]	77	76		159	154
Total operating expenses		627	583		1,375	1,194
Other income (expense), net	[4]	3	1		6	2
Interest charges, net of AFUDC	[2]	70	67		141	134
Income tax expense	[2]	29	14		47	31
Comprehensive Income Attributable to Noncontrolling Interest	[4]	6	6		14	12
Comprehensive Income (Loss) Available (Attributable) to Common Shareholder		103	62		247	137
Capital expenditures					561	490
Total assets		17,300			17,300
Corporate and Other
Segment Reporting Information [Line Items]
Operating Revenue		0	0		0	0
Fuel used in electric generation	[2]	0	0		0	0
Purchased power	[2]	0	0		0	0
Gas purchased for resale	[2]	0	0		0	0
Other operations and maintenance	[2]	0	4	[3]	0	4	[3]
Depreciation and amortization	[2]	0	0		0	0
Other taxes	[2]	0	0		0
Total operating expenses		0	4		0	4
Other income (expense), net	[4]	0	0		0	0
Interest charges, net of AFUDC	[2]	0	0		0	0
Income tax expense	[2]	2	1		4	2
Comprehensive Income Attributable to Noncontrolling Interest	[4]	0	0		0	0
Comprehensive Income (Loss) Available (Attributable) to Common Shareholder		(2)	$ (5)		(4)	(6)
Capital expenditures					0	$ 0
Total assets		$ 0			$ 0

[1] See Note 12 for amounts attributable to affiliates.

[2] The significant expense categories and amounts in the segment information presented above align with the segment-level information that is regularly provided to DESC’s CODM.

[3] Includes impairment of assets and other charges.

[4] Items designated are other segment items for each reportable segment.