Regulatory - Schedule of Regulatory Assets and Regulatory Liabilities (Parenthetical) (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($)
Capital Cost Recovery for Early Retired Assets [Member]
Schedule Of Regulatory Assets And Liabilities [Line Items]
Settlement agreement cost recovery period	15 years
Storm Reserve [Member]
Schedule Of Regulatory Assets And Liabilities [Line Items]
Recovery of cost reserve	$ 56