Cash and Cash Equivalents and Restricted Cash and Cash Equivalents - SPPC (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	$ 3,744	$ 1,565
Restricted cash and cash equivalents	201	224
Total cash and cash equivalents and restricted cash and cash equivalents	3,959	1,811	$ 1,155	$ 1,817
SPPC
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	96	44
Restricted cash and cash equivalents	8	8
Total cash and cash equivalents and restricted cash and cash equivalents	$ 104	$ 52	$ 17	$ 56