Long-Term Debt (Based on Stated Maturity Dates Rather than Early Redemption Dates that Could be Elected by Instrument Holders) (Detail) $ in Millions	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
2021	$ 2,110
2022	1,553
2023	2,966
2024	1,564
2025	2,019
Thereafter	25,284
Total	$ 35,496
Weighted- average coupon, 2021	2.93%
Weighted- average coupon, 2022	2.96%
Weighted- average coupon, 2023	1.98%
Weighted- average coupon, 2024	3.17%
Weighted- average coupon, 2025	3.01%
Weighted- average coupon, Thereafter	4.45%
Unsecured senior notes
Debt Instrument [Line Items]
2021	$ 550	[1],[2]
2022	1,500	[1],[2]
2023	2,700	[1],[2]
2024	690	[1],[2]
2025	2,000	[1],[2]
Thereafter	19,537	[1],[2]
Total	26,977	[1],[2]
Tax-exempt financings
Debt Instrument [Line Items]
Thereafter	775
Total	775
Supplemental 364-Day Credit Facility
Debt Instrument [Line Items]
2021	225
Total	225
Term loans
Debt Instrument [Line Items]
2021	35	[3]
2022	34	[3]
2023	250	[3]
2024	157	[3]
Total	476	[3]
First mortgage bonds
Debt Instrument [Line Items]
2021	33
Thereafter	3,234
Total	3,267
Secured senior notes
Debt Instrument [Line Items]
2021	17
2022	19
2023	16
2024	17
2025	19
Thereafter	243
Total	331
Unsecured junior subordinated notes payable to affiliated trusts
Debt Instrument [Line Items]
Thereafter	10
Total	10
Unsecured Junior Subordinated Notes
Debt Instrument [Line Items]
2021	1,250	[4]
2024	700	[4]
Total	1,950	[4]
Enhanced Junior Subordinated Notes
Debt Instrument [Line Items]
Thereafter	1,485	[5]
Total	1,485	[5]
Virginia Electric and Power Company
Debt Instrument [Line Items]
2022	750
2023	700
2024	350
2025	350
Thereafter	11,164
Total	$ 13,314
Weighted- average coupon, 2022	3.15%
Weighted- average coupon, 2023	2.75%
Weighted- average coupon, 2024	3.45%
Weighted- average coupon, 2025	3.10%
Weighted- average coupon, Thereafter	4.18%
Virginia Electric and Power Company | Unsecured senior notes
Debt Instrument [Line Items]
2022	$ 750
2023	700
2024	350
2025	350
Thereafter	10,539
Total	12,689
Virginia Electric and Power Company | Tax-exempt financings
Debt Instrument [Line Items]
Thereafter	625
Total	$ 625

[1] In February 2020, SCANA provided notice to redeem the remaining principal outstanding of $183 million of its 4.75% medium-term notes and $155 million of its 4.125% medium-term notes plus accrued interest and make-whole premiums in March 2020. The notes would have otherwise matured in May 2021 and February 2022, respectively.

[2] In January 2020, SCANA provided notice to redeem its floating rate senior notes at the remaining principal outstanding of $66 million plus accrued interest in March 2020. The notes would have otherwise matured in June 2034

[3] Excludes mandatory prepayments associated with SBL Holdco and Dominion Solar Projects III, Inc. based on cash flows in excess of debt service. At December 31, 2020, $22 million of estimated mandatory prepayments due within one year were included in securities due within one year in Dominion Energy’s Consolidated Balance Sheets.

[4] In April 2020, Dominion Energy purchased and canceled $7 million of its 2.579% junior subordinated notes that mature in July 2020. In June 2020, Dominion Energy prepaid the remaining balance of $993 million.

[5] In February 2020, Dominion Energy purchased and cancelled the remaining $111 million and $286 million of its June 2006 hybrids and September 2006 hybrids, respectively, both of which would have otherwise matured in 2066. As such, these borrowings are presented within current liabilities in Dominion Energy’s Consolidated Balance Sheets at December 31, 2019.