Property, Plant and Equipment (Narrative) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Line Items]
Impairment of assets and other charges	$ 30	$ 98
Level 3 | Corporate Office Building
Property, Plant and Equipment [Line Items]
Long-lived assets, estimated fair value		35
Impairment of Assets and Other Charges | Corporate Office Building
Property, Plant and Equipment [Line Items]
Impairment of assets and other charges		91
Asset impairment charges after tax		$ 68
Acquisition of Solar Project Foxhound Virginia
Property, Plant and Equipment [Line Items]
Date Agreement Entered	2023-03
Date Agreement Closed	February 2024
Date of Commercial Operations	April 2024