Fair Value Measurements (Fair Value, Option, Quantitative Disclosures) (Detail) $ in Millions | 6 Months Ended | |
Jun. 30, 2023 USD ($) $ / MMBTU $ / MWh | Dec. 31, 2022 USD ($) |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Assets | | $ 1,255 | $ 2,176 |
Fair Value of Derivative Liabilities | | 794 | 1,404 |
Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Assets | | 224 | 882 |
Fair Value of Derivative Liabilities | | 238 | 456 |
Fair Value, Measurements, Recurring | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Total assets | | 7,489 | 7,782 |
Total liabilities | | 794 | 1,404 |
Fair Value, Measurements, Recurring | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Total assets | | 3,574 | 3,902 |
Total liabilities | | 238 | 456 |
Fair Value, Measurements, Recurring | Commodity Contract | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Assets | | 351 | 769 |
Fair Value of Derivative Liabilities | | 354 | 926 |
Fair Value, Measurements, Recurring | Commodity Contract | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Assets | | 89 | 268 |
Fair Value of Derivative Liabilities | | 168 | 348 |
Fair Value, Measurements, Recurring | Level 3 | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Total assets | | 156 | 437 |
Total liabilities | | 22 | 15 |
Fair Value, Measurements, Recurring | Level 3 | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Total assets | | 15 | 236 |
Total liabilities | | 18 | 15 |
Fair Value, Measurements, Recurring | Level 3 | Commodity Contract | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Assets | | 156 | 437 |
Fair Value of Derivative Liabilities | | 22 | 15 |
Fair Value, Measurements, Recurring | Level 3 | Commodity Contract | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Assets | | 15 | 236 |
Fair Value of Derivative Liabilities | | 18 | $ 15 |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Natural Gas | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Liabilities | [1],[2] | $ 18 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Natural Gas | Minimum | Liabilities | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MMBTU | [1],[2] | (2) | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Natural Gas | Minimum | Liabilities | Market Price | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MMBTU | [1],[2] | (2) | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Natural Gas | Maximum | Liabilities | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MMBTU | [1],[2] | 2 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Natural Gas | Maximum | Liabilities | Market Price | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MMBTU | [1],[2] | 2 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Natural Gas | Weighted Average | Assets | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [1],[2] | 4 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Natural Gas | Weighted Average | Assets | Market Price | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [1],[2] | 4 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Natural Gas | Weighted Average | Liabilities | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [1],[2] | (1) | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Natural Gas | Weighted Average | Liabilities | Market Price | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [1],[2] | (1) | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Electricity | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Assets | [2] | $ 141 | |
Fair Value of Derivative Liabilities | [2] | $ 4 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Electricity | Minimum | Assets | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [2] | 25 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Electricity | Minimum | Liabilities | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [2] | 32 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Electricity | Maximum | Assets | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [2] | 138 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Electricity | Maximum | Liabilities | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [2] | 138 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Electricity | Weighted Average | Assets | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [2] | 47 | |
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flow | Commodity Contract | Electricity | Weighted Average | Liabilities | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MWh | [2] | 64 | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Assets | [1],[2] | $ 15 | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Fair Value of Derivative Assets | [1],[2] | 15 | |
Fair Value of Derivative Liabilities | [1],[2] | $ 18 | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Minimum | Assets | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MMBTU | [1],[2] | 1 | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Minimum | Assets | Market Price | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MMBTU | [1],[2] | 1 | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Minimum | Assets | Price Volatility | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Price volatility (percentage) | [3] | 19% | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Minimum | Assets | Price Volatility | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Price volatility (percentage) | [3] | 19% | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Maximum | Assets | Market Price | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MMBTU | [1],[2] | 8 | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Maximum | Assets | Market Price | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Market Price | $ / MMBTU | [1],[2] | 8 | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Maximum | Assets | Price Volatility | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Price volatility (percentage) | [3] | 72% | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Maximum | Assets | Price Volatility | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Price volatility (percentage) | [3] | 72% | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Weighted Average | Liabilities | Price Volatility | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Price volatility (percentage) | [3],[4] | 51% | |
Fair Value, Measurements, Recurring | Level 3 | Option Model | Commodity Contract | Natural Gas | Weighted Average | Liabilities | Price Volatility | Virginia Electric and Power Company | | | |
Fair Value, Option, Quantitative Disclosures [Line Items] | | | |
Price volatility (percentage) | [3],[4] | 51% | |
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[1] Includes basis. Represents market prices beyond defined terms for Levels 1 and 2. Represents volatilities unrepresented in published markets. Averages weighted by volume. | |