Operating Revenue (Disaggregation of Revenue) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Total Operating Revenues	[1]	$ 3,028	$ 3,783	$ 3,146
Electric Operations
Operating revenue from contracts with customers		2,502	3,079	2,626
Other revenues		27	27	13
Total Operating Revenues		2,529	3,106	2,639
Gas Distribution
Operating revenue from contracts with customers		498	676	506
Other revenues		1	1	1
Total Operating Revenues		499	677	507
Residential | Electric Operations
Operating revenue from contracts with customers		1,160	1,375	1,211
Residential | Gas Distribution
Operating revenue from contracts with customers		268	303	245
Commercial | Electric Operations
Operating revenue from contracts with customers		820	968	834
Commercial | Gas Distribution
Operating revenue from contracts with customers		129	184	133
Industrial | Electric Operations
Operating revenue from contracts with customers		372	533	424
Industrial | Gas Distribution
Operating revenue from contracts with customers		77	166	103
Other | Electric Operations
Operating revenue from contracts with customers		150	203	157
Other | Gas Distribution
Operating revenue from contracts with customers		$ 24	$ 23	$ 25

[1] See Note 16 for amounts attributable to affiliates.