FAIR VALUE MEASUREMENTS - RECURRING FAIR VALUE MEASURES (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at NAV		$ 5
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	$ 362	509
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	52	57
Nuclear decommissioning trusts - Municipal bonds	343	282
Nuclear decommissioning trusts - Other securities	294	226
Nuclear decommissioning trusts - Total debt securities	689	565
Total nuclear decommissioning trusts	1,051	1,074
Total Assets Measured at Fair Value	1,208	1,285
Total Liabilities Measured at Fair Value	339	245
Recurring [Member] | Interest rate and foreign exchange instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	9	24
Derivative liabilities	253	157
Recurring [Member] | Commodity contracts not subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	9	11
Effect of netting and allocation of collateral	27	43
Derivative liabilities	10	17
Recurring [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	93	108
Effect of netting and allocation of collateral	19	25
Derivative liabilities	87	85
Effect of netting and allocation of collateral	(11)	(14)
Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	356	503
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	26	46
Nuclear decommissioning trusts - Municipal bonds	0	0
Nuclear decommissioning trusts - Other securities	0	0
Nuclear decommissioning trusts - Total debt securities	26	46
Total nuclear decommissioning trusts	382	549
Total Assets Measured at Fair Value	425	608
Total Liabilities Measured at Fair Value	0	0
Recurring [Member] | Level 1 [Member] | Interest rate and foreign exchange instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Recurring [Member] | Level 1 [Member] | Commodity contracts not subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Effect of netting and allocation of collateral	27	43
Derivative liabilities	0	0
Recurring [Member] | Level 1 [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	3	5
Effect of netting and allocation of collateral	13	11
Derivative liabilities	11	14
Effect of netting and allocation of collateral	(11)	(14)
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	6	6
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	26	11
Nuclear decommissioning trusts - Municipal bonds	343	282
Nuclear decommissioning trusts - Other securities	294	226
Nuclear decommissioning trusts - Total debt securities	663	519
Total nuclear decommissioning trusts	669	525
Total Assets Measured at Fair Value	690	576
Total Liabilities Measured at Fair Value	269	178
Recurring [Member] | Level 2 [Member] | Interest rate and foreign exchange instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	9	24
Derivative liabilities	253	157
Recurring [Member] | Level 2 [Member] | Commodity contracts not subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	9	11
Effect of netting and allocation of collateral	0	0
Derivative liabilities	10	17
Recurring [Member] | Level 2 [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	3	8
Effect of netting and allocation of collateral	0	8
Derivative liabilities	6	4
Effect of netting and allocation of collateral	0	0
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	0	0
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	0	0
Nuclear decommissioning trusts - Municipal bonds	0	0
Nuclear decommissioning trusts - Other securities	0	0
Nuclear decommissioning trusts - Total debt securities	0	0
Total nuclear decommissioning trusts	0	0
Total Assets Measured at Fair Value	93	101
Total Liabilities Measured at Fair Value	70	67
Recurring [Member] | Level 3 [Member] | Interest rate and foreign exchange instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Recurring [Member] | Level 3 [Member] | Commodity contracts not subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Effect of netting and allocation of collateral	0	0
Derivative liabilities	0	0
Recurring [Member] | Level 3 [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	87	95
Effect of netting and allocation of collateral	6	6
Derivative liabilities	70	67
Effect of netting and allocation of collateral	0	0
San Diego Gas and Electric Company [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	362	509
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	52	57
Nuclear decommissioning trusts - Municipal bonds	343	282
Nuclear decommissioning trusts - Other securities	294	226
Nuclear decommissioning trusts - Total debt securities	689	565
Total nuclear decommissioning trusts	1,051	1,074
Total Assets Measured at Fair Value	1,155	1,189
Total Liabilities Measured at Fair Value	70	67
San Diego Gas and Electric Company [Member] | Recurring [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	89	99
Effect of netting and allocation of collateral	15	16
Derivative liabilities	81	81
Effect of netting and allocation of collateral	(11)	(14)
San Diego Gas and Electric Company [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	356	503
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	26	46
Nuclear decommissioning trusts - Municipal bonds	0	0
Nuclear decommissioning trusts - Other securities	0	0
Nuclear decommissioning trusts - Total debt securities	26	46
Total nuclear decommissioning trusts	382	549
Total Assets Measured at Fair Value	392	560
Total Liabilities Measured at Fair Value	0	0
San Diego Gas and Electric Company [Member] | Recurring [Member] | Level 1 [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1	1
Effect of netting and allocation of collateral	9	10
Derivative liabilities	11	14
Effect of netting and allocation of collateral	(11)	(14)
San Diego Gas and Electric Company [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	6	6
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	26	11
Nuclear decommissioning trusts - Municipal bonds	343	282
Nuclear decommissioning trusts - Other securities	294	226
Nuclear decommissioning trusts - Total debt securities	663	519
Total nuclear decommissioning trusts	669	525
Total Assets Measured at Fair Value	670	528
Total Liabilities Measured at Fair Value	0	0
San Diego Gas and Electric Company [Member] | Recurring [Member] | Level 2 [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1	3
Effect of netting and allocation of collateral	0	0
Derivative liabilities	0	0
Effect of netting and allocation of collateral	0	0
San Diego Gas and Electric Company [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	0	0
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	0	0
Nuclear decommissioning trusts - Municipal bonds	0	0
Nuclear decommissioning trusts - Other securities	0	0
Nuclear decommissioning trusts - Total debt securities	0	0
Total nuclear decommissioning trusts	0	0
Total Assets Measured at Fair Value	93	101
Total Liabilities Measured at Fair Value	70	67
San Diego Gas and Electric Company [Member] | Recurring [Member] | Level 3 [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	87	95
Effect of netting and allocation of collateral	6	6
Derivative liabilities	70	67
Effect of netting and allocation of collateral	0	0
Southern California Gas Company [Member] | Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets Measured at Fair Value	8	18
Total Liabilities Measured at Fair Value	6	4
Southern California Gas Company [Member] | Recurring [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	4	9
Effect of netting and allocation of collateral	4	9
Derivative liabilities	6	4
Southern California Gas Company [Member] | Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets Measured at Fair Value	6	5
Total Liabilities Measured at Fair Value	0	0
Southern California Gas Company [Member] | Recurring [Member] | Level 1 [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	2	4
Effect of netting and allocation of collateral	4	1
Derivative liabilities	0	0
Southern California Gas Company [Member] | Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets Measured at Fair Value	2	13
Total Liabilities Measured at Fair Value	6	4
Southern California Gas Company [Member] | Recurring [Member] | Level 2 [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	2	5
Effect of netting and allocation of collateral	0	8
Derivative liabilities	6	4
Southern California Gas Company [Member] | Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets Measured at Fair Value	0	0
Total Liabilities Measured at Fair Value	0	0
Southern California Gas Company [Member] | Recurring [Member] | Level 3 [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Effect of netting and allocation of collateral	0	0
Derivative liabilities	$ 0	$ 0