SEMPRA ENERGY - SHAREHOLDERS' EQUITY AND EARNINGS PER SHARE - COMMON STOCK ACTIVITY (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Common stock, shares authorized (in shares)	750,000,000	750,000,000
Common stock par value (in dollars per share)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common shares outstanding, January 1	251,358,977	250,152,514	248,298,080
Shares issued under forward sale agreements	21,175,473	0	0
RSUs vesting	509,042	362,022	1,363,555
Stock options exercised	138,861	164,454	167,742
Savings plan issuance	553,036	567,428	653,607
Common stock investment plan	231,242	254,047	266,056
Issuance of RSUs held in our Deferred Compensation Plan	3,357	7,811	0
Shares repurchased	(200,475)	(149,299)	(596,526)
Common shares outstanding, December 31	273,769,513	251,358,977	250,152,514