GENERAL INFORMATION AND OTHER FINANCIAL DATA - SHAREHOLDER'S EQUITY AND NONCONTROLLING INTEREST (Details) $ / shares in Units, $ in Millions				1 Months Ended			3 Months Ended				6 Months Ended
	Jul. 06, 2021 $ / shares	Apr. 04, 2021 USD ($)	Jun. 19, 2020 USD ($) $ / shares shares	Jul. 31, 2021 USD ($)	May 31, 2021 USD ($) shares	Mar. 31, 2020 USD ($)	Sep. 30, 2021 USD ($) shares	Jun. 30, 2021 USD ($) class	Jun. 30, 2020 USD ($) shares	Mar. 31, 2020 USD ($)	Jun. 30, 2021 USD ($) class	Jun. 30, 2020 USD ($)	Jul. 15, 2021 shares	Apr. 30, 2021	Jan. 15, 2021 shares	Mar. 30, 2020	Dec. 31, 2019
Subsidiary, Sale of Stock [Line Items]
Shares issued (in shares) | shares					12,306,777
Repurchases of common stock								$ 1.0	$ 7.0		$ 38.0	$ 64.0
Equitization of long-term debt for deficit held by NCI												$ 22.0
Limited Partnership distributions (as a percent)		85.00%
Number of authorized classes of units | class								2			2
Forecast [Member]
Subsidiary, Sale of Stock [Line Items]
Direct and indirect net debt at closing							$ 8,370.0
KKR [Member]
Subsidiary, Sale of Stock [Line Items]
Termination fee received		$ 134.8
Expenses paid in connection with transaction		150.0
Disbursements to be paid		$ 300.0
Repayment of disbursements, rate (as a percent)		5.00%
Infraestructura Energética Nova [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock acquired (in shares) | shares					381,015,194
Common stock exchange ratio					0.0323
Infraestructura Energética Nova [Member] | Subsequent Event [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock acquired (in shares) | shares							52,227,526
LA Storage [Member] | Liberty Gas Storage, LLC [Member]
Subsidiary, Sale of Stock [Line Items]
Ownership percentage								100.00%			100.00%
IEnova [Member]
Subsidiary, Sale of Stock [Line Items]
Purchase price of equity interests					$ 1,361.0
Transaction costs					$ 12.0
Ownership interest (as a percent)					96.40%			96.40%			96.40%			70.20%
Sempra Global | KKR [Member]
Subsidiary, Sale of Stock [Line Items]
Purchase price of equity interests		$ 3,370.0
Sempra Global | KKR [Member]
Subsidiary, Sale of Stock [Line Items]
Ownership percentage		20.00%
Liberty Gas Storage, LLC [Member] | Sempra LNG [Member]
Subsidiary, Sale of Stock [Line Items]
Payment to acquire remaining interest						$ 7.0
Equitization of long-term debt for deficit held by NCI						22.0
Increase from equity of noncontrolling interest						$ 2.0
Sempra Mexico [Member] | ICM Ventures Holdings B.V. [Member] | Subsequent Event [Member]
Subsidiary, Sale of Stock [Line Items]
Additional ownership percentage	17.50%
Sempra Mexico [Member] | Infraestructura Energética Nova [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock repurchased (in shares) | shares									3,694,156
Repurchases of common stock									$ 10.0
Sempra Mexico [Member] | ICM Ventures Holdings B.V. [Member]
Subsidiary, Sale of Stock [Line Items]
Ownership interest (as a percent)						82.50%				82.50%							53.70%
Payment to acquire remaining interest										$ 9.0
Sempra Mexico [Member] | ICM Ventures Holdings B.V. [Member] | Subsequent Event [Member]
Subsidiary, Sale of Stock [Line Items]
Payment to acquire remaining interest				$ 7.0
Sempra Mexico [Member] | IEnova [Member]
Subsidiary, Sale of Stock [Line Items]
Ownership interest (as a percent)									66.80%			66.80%					66.60%
Sempra LNG [Member] | Liberty Gas Storage, LLC [Member]
Subsidiary, Sale of Stock [Line Items]
Ownership percentage																24.60%
Sempra LNG [Member] | Liberty Gas Storage, LLC [Member] | Liberty Gas Storage, LLC [Member]
Subsidiary, Sale of Stock [Line Items]
Ownership percentage								100.00%			100.00%
Series A Preferred Stock [Member]
Subsidiary, Sale of Stock [Line Items]
Shares converted | shares															17,250,000
Convertible Preferred Stock Series A [Member]
Subsidiary, Sale of Stock [Line Items]
Shares converted | shares															13,781,025
Preferred stock, conversion ratio															0.7989
Series B Preferred Stock [Member] | Subsequent Event [Member]
Subsidiary, Sale of Stock [Line Items]
Shares converted | shares													5,750,000
Series B Preferred Stock [Member] | Sempra Energy [Member]
Subsidiary, Sale of Stock [Line Items]
Percentage of common shares held (as a percent)								1.00%			1.00%
Series B Preferred Stock [Member] | Sempra Energy [Member] | Subsequent Event [Member]
Subsidiary, Sale of Stock [Line Items]
Stock price trigger amount | $ / shares	$ 135.0804
Conversion ratio (in shares)	0.8883
Conversion price | $ / shares	$ 100.00
Series B Preferred Stock [Member] | Sempra Energy [Member] | Subsequent Event [Member] | Minimum [Member]
Subsidiary, Sale of Stock [Line Items]
Stock price trigger amount | $ / shares	$ 112.5746
Conversion ratio (in shares)	0.7403
Series B Preferred Stock [Member] | Sempra Energy [Member] | Subsequent Event [Member] | Maximum [Member]
Subsidiary, Sale of Stock [Line Items]
Stock price trigger amount | $ / shares	$ 112.5746
Conversion ratio (in shares)	0.8883
Convertible Preferred Stock Series B [Member] | Subsequent Event [Member]
Subsidiary, Sale of Stock [Line Items]
Shares converted | shares													4,256,720
Preferred stock, conversion ratio													0.7403
Series C Preferred Stock [Member]
Subsidiary, Sale of Stock [Line Items]
Preferred stock, shares issued (in shares) | shares			900,000
Preferred stock, redemption price per share (in dollars per share) | $ / shares			$ 1,000
Proceeds from issuance of preferred stock			$ 889.0
Preferred stock, discount			$ 11.0
Debt Instrument, Interest Rate, Stated Percentage			4.875%