SEMPRA - EQUITY AND EARNINGS PER COMMON SHARE - COMMON STOCK NARRATIVE (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2025	Dec. 31, 2024	Sep. 30, 2025	Sep. 30, 2024	Nov. 30, 2024
SI Partners and ConocoPhillips | Port Arthur LNG I
Equity, Class of Treasury Stock [Line Items]
Funding commitment, aggregate amount			$ 9,000.0
SI Partners | Port Arthur LNG I
Equity, Class of Treasury Stock [Line Items]
Funding commitment paid			$ 2,700.0
Port Arthur LNG I | SI Partners and ConocoPhillips
Equity, Class of Treasury Stock [Line Items]
Funding commitment (in percent)			110.00%
Port Arthur LNG I | SI Partners
Equity, Class of Treasury Stock [Line Items]
Guaranteed funding amount (in percent)			70.00%
Common stock
Equity, Class of Treasury Stock [Line Items]
Shares withheld for tax purposes (in shares)			684,447	565,571
Shares withheld for tax purposes			$ 58.0	$ 41.0
At The Market Program Offering
Equity, Class of Treasury Stock [Line Items]
Aggregate sales price					$ 3,000.0
Underwriting commission, percent					1.00%
Aggregate sales price remaining			$ 2,600.0
Number of shares issued since inception (in shares)			4,996,591
Average price per share since inception (usd per share)			$ 83.175
Q4 2024 Forward Sale Agreement
Equity, Class of Treasury Stock [Line Items]
Number of shares sold (in shares)		2,909,274
Sale of stock, price per share (usd per share)		$ 92.1546
Expected net proceeds		$ 268.0
Sales commissions		$ 2.4
Number of shares that remain to be settled (in shares)			2,909,274
Q1 2025 Forward Sale Agreement
Equity, Class of Treasury Stock [Line Items]
Number of shares sold (in shares)	2,087,317
Sale of stock, price per share (usd per share)	$ 70.6593
Expected net proceeds	$ 147.0
Sales commissions	$ 1.3
Number of shares that remain to be settled (in shares)			2,087,317