Fair Value Measurements, Including Derivatives (Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis and Included in Level 3) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Regulatory Assets
Beginning balance	$ 251	$ 148	$ 0
Included in earnings:
Purchased power	6	77	8
Settlements	(6)	(77)	(8)
Ending balance	176	251	148
Other Regulatory Assets Liabilities
Included in earnings:
Included in regulatory assets/liabilities	$ (75)	$ 103	$ 148