Income Taxes - SPPC - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	$ 1,248	$ 1,323
Other	629	632
Total deferred income tax assets	3,400	3,159
Property-related items	(12,596)	(12,244)
Regulatory assets	(1,034)	(898)
Other	(491)	(510)
Total deferred income tax liabilities	(15,695)	(15,650)
Net deferred income tax liability	(12,437)	(12,678)
SPPC
Deferred Tax Assets and Liabilities [Line Items]
Regulatory liabilities	62	63
Operating and finance leases	25	26
Customer advances	16	17
Derivative contracts and unamortized contract values	3	6
Other	5	6
Total deferred income tax assets	111	118
Property-related items	(376)	(387)
Regulatory assets	(100)	(135)
Operating and finance leases	(24)	(25)
Other	(15)	(16)
Total deferred income tax liabilities	(515)	(563)
Net deferred income tax liability	$ (404)	$ (445)