Fair Value Measurements - SPPC - Level 3 (Details) - Commodity - SPPC - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Fair Value, Assets (Liabilities), Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (52)	$ 12	$ (33)	$ 7
Changes in fair value recognized in regulatory assets	(7)	(1)	(26)	4
Settlements	5	1	5	1
Ending balance	$ (54)	$ 12	$ (54)	$ 12