Regulatory Matters - SPPC - Regulatory Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 7,369	$ 7,214
Regulatory liabilities, current	299	254
Regulatory liabilities, noncurrent	$ 7,070	6,960
Cost of removal
Regulatory Liabilities [Line Items]
Regulatory liability, amortization period	27 years
Total regulatory liabilities	$ 2,578	2,424
Other
Regulatory Liabilities [Line Items]
Total regulatory liabilities	446	484
SPPC
Regulatory Liabilities [Line Items]
Total regulatory liabilities	455	463
Regulatory liabilities, current	19	19
Regulatory liabilities, noncurrent	436	444
SPPC | Deferred income taxes
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 223	234
SPPC | Cost of removal
Regulatory Liabilities [Line Items]
Regulatory liability, amortization period	35 years
Total regulatory liabilities	$ 200	201
SPPC | Other
Regulatory Liabilities [Line Items]
Total regulatory liabilities	$ 32	$ 28