Cash and Cash Equivalents and Restricted Cash and Cash Equivalents - SPPC (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	$ 1,432	$ 1,096
Restricted cash and cash equivalents	129	127
Total cash and cash equivalents and restricted cash and cash equivalents	1,582	1,244	$ 1,406	$ 1,445
SPPC
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	15	10
Restricted cash and cash equivalents	7	6
Total cash and cash equivalents and restricted cash and cash equivalents	$ 22	$ 16	$ 15	$ 26