Retirement Benefits and Trusteed Assets (Pension Plan - Other Changes in Plan Assets and Benefit Obligations recognized in Regulatory Assets and OCI) (Details) - Pension plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Other changes in plan assets and benefit obligations recognized in Regulatory assets and Other comprehensive income (loss)
Net actuarial (gain) loss	$ (49)	$ 62
Amortization of net actuarial loss and settlements	(59)	(14)
Amortization of prior service credit	2	2
Total recognized in Regulatory assets and liabilities and Other comprehensive income (loss)	(106)	50
Total recognized in net periodic pension credit, Regulatory assets, and Other comprehensive income (loss)	$ (124)	$ (19)