Investments (Investments Under Equity Method of Accounting) (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Current assets held for sale	$ 18,529		$ 1,785
Noncurrent assets held for sale			18,831
Other Investment
Schedule of Equity Method Investments [Line Items]
Current assets held for sale	43		43
Noncurrent assets held for sale	43		43
Cove Point
Schedule of Equity Method Investments [Line Items]
Noncurrent assets held for sale			2,700
Cove Point | Limited Partnership Interest
Schedule of Equity Method Investments [Line Items]
Percentage of noncontrolling limited partnership interest retained		50.00%
Atlantic Coast Pipeline | Other Current Liabilities
Schedule of Equity Method Investments [Line Items]
Liability associated with its investment	$ 4		$ 114