Business Developments And Risks And Uncertainties (Narrative) (Detail) $ / shares in Units, $ in Millions			1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 01, 2024 USD ($)	Dec. 07, 2023 USD ($) $ / shares	Nov. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) Segments	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 26, 2023 USD ($)
Business Acquisition [Line Items]
Number of operating segments | Segments					3
Correction of error income (loss) from discontinued operations, net of tax				$ 18
Dividends paid					$ 409	$ 0	$ 0
Dividend declared per common share | $ / shares		$ 8
Dividend payment date					Dec. 22, 2023
Special Dividend [Member]
Business Acquisition [Line Items]
Dividends paid		$ 550
Right Dividend [Member]
Business Acquisition [Line Items]
Dividends paid			$ 97
Noncontrolling Interest [Member]
Business Acquisition [Line Items]
Correction of error income (loss) from discontinued operations, net of tax				$ 8
Puerto Rico Electric Power Authority [Member]
Business Acquisition [Line Items]
Claims payments					$ 137
Outstanding bonds					$ 808
Subsequent Event | Puerto Rico Electric Power Authority [Member]
Business Acquisition [Line Items]
Claims payments	$ 16
Maximum [Member]
Business Acquisition [Line Items]
Liabilities Subject to Compromise, Provision for Expected and Allowed Claims								$ 7,600
Minimum [Member]
Business Acquisition [Line Items]
Liabilities Subject to Compromise, Provision for Expected and Allowed Claims								$ 2,400