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, 2019 USD ($)
Debt Instrument [Line Items]
2020	$ 2,325
2021	2,572
2022	1,712
2023	2,630
2024	2,626
Thereafter	25,253
Total	$ 37,118
Weighted- average coupon, 2020	3.09%
Weighted- average coupon, 2021	3.15%
Weighted- average coupon, 2022	3.10%
Weighted- average coupon, 2023	2.95%
Weighted- average coupon, 2024	3.19%
Weighted- average coupon, Thereafter	4.62%
First mortgage bonds
Debt Instrument [Line Items]
2021	$ 33
Thereafter	3,234
Total	3,267
Unsecured senior notes
Debt Instrument [Line Items]
2020	1,275	[1],[2]
2021	1,237	[1],[2]
2022	1,659	[1],[2]
2023	2,355	[1],[2]
2024	1,745	[1],[2]
Thereafter	19,092	[1],[2]
Total	27,363	[1],[2]
Tax-exempt financings
Debt Instrument [Line Items]
Thereafter	774
Total	774
Term loans
Debt Instrument [Line Items]
2020	35	[3]
2021	35	[3]
2022	34	[3]
2023	259	[3]
2024	164	[3]
Total	527	[3]
Secured senior notes
Debt Instrument [Line Items]
2020	15
2021	17
2022	19
2023	16
2024	17
Thereafter	261
Total	345
Unsecured junior subordinated notes payable to affiliated trusts
Debt Instrument [Line Items]
Thereafter	10
Total	10
Unsecured junior subordinated notes
Debt Instrument [Line Items]
2020	1,000
2021	1,250
2022	0
2024	700
Total	2,950
Enhanced junior subordinated notes
Debt Instrument [Line Items]
Thereafter	1,882	[1]
Total	1,882	[1]
Dominion Energy Gas Holdings, LLC
Debt Instrument [Line Items]
2020	700
2021	500
2023	650
2024	1,050
Thereafter	2,661
Total	$ 5,561
Weighted- average coupon, 2020	2.80%
Weighted- average coupon, 2021	2.49%
Weighted- average coupon, 2023	3.29%
Weighted- average coupon, 2024	2.97%
Weighted- average coupon, Thereafter	3.95%
Virginia Electric and Power Company
Debt Instrument [Line Items]
2022	$ 750
2023	700
2024	350
Thereafter	10,614
Total	$ 12,414
Weighted- average coupon, 2022	3.15%
Weighted- average coupon, 2023	2.75%
Weighted- average coupon, 2024	3.45%
Weighted- average coupon, Thereafter	4.35%
Virginia Electric and Power Company | Unsecured senior notes
Debt Instrument [Line Items]
2022	$ 750
2023	700
2024	350
Thereafter	9,989
Total	11,789
Virginia Electric and Power Company | Tax-exempt financings
Debt Instrument [Line Items]
Thereafter	625
Total	$ 625

[1] 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.

[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, 2019, $20 million of estimated mandatory prepayments due within one year were included in securities due within one year in Dominion Energy’s Consolidated Balance Sheets.