Consolidated Balance Sheets - SPPC (Parenthetical) - $ / shares	Dec. 31, 2024	Dec. 31, 2023
Common stock, shares authorized (in shares)	100	115,000,000
Common stock, shares issued (in shares)	1	75,627,913
Common stock, shares outstanding (in shares)	1	75,627,913
SPPC
Common stock, par value (in dollars per share)	$ 3.75	$ 3.75
Common stock, shares authorized (in shares)	1,000	1,000
Common stock, shares issued (in shares)	1,000	1,000
Common stock, shares outstanding (in shares)	1,000	1,000