FAIR VALUE MEASUREMENTS - RECURRING FAIR VALUE MEASURES (Details) - Recurring [Member] - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	$ 607,000,000	$ 619,000,000
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	100,000,000	91,000,000
Nuclear decommissioning trusts - Municipal bonds	161,000,000	156,000,000
Nuclear decommissioning trusts - Other securities	188,000,000	182,000,000
Nuclear decommissioning trusts - Total debt securities	449,000,000	429,000,000
Nuclear decommissioning trusts - Netting	0	0
Total nuclear decommissioning trusts	1,056,000,000	1,048,000,000
Derivative asset netting	32,000,000	24,000,000
Total	1,202,000,000	1,188,000,000
Derivative liability netting	(48,000,000)	(58,000,000)
Total	459,000,000	242,000,000
Interest rate and foreign exchange instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	5,000,000	5,000,000
Derivative asset netting	0	0
Derivative liabilities	269,000,000	171,000,000
Derivative liability netting	0	0
Commodity contracts not subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	31,000,000	34,000,000
Derivative asset netting	13,000,000	(4,000,000)
Derivative liabilities	1,000,000	4,000,000
Derivative liability netting	(19,000,000)	(4,000,000)
Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	110,000,000	101,000,000
Derivative asset netting	19,000,000	28,000,000
Derivative liabilities	189,000,000	67,000,000
Derivative liability netting	(29,000,000)	(54,000,000)
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	607,000,000	619,000,000
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	48,000,000	47,000,000
Nuclear decommissioning trusts - Municipal bonds	0	0
Nuclear decommissioning trusts - Other securities	0	0
Nuclear decommissioning trusts - Total debt securities	48,000,000	47,000,000
Total nuclear decommissioning trusts	655,000,000	666,000,000
Total	655,000,000	688,000,000
Total	20,000,000	5,000,000
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
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	22,000,000
Derivative liabilities	19,000,000	5,000,000
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	0	0
Derivative liabilities	1,000,000	0
Level 2 [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	52,000,000	44,000,000
Nuclear decommissioning trusts - Municipal bonds	161,000,000	156,000,000
Nuclear decommissioning trusts - Other securities	188,000,000	182,000,000
Nuclear decommissioning trusts - Total debt securities	401,000,000	382,000,000
Total nuclear decommissioning trusts	401,000,000	382,000,000
Total	425,000,000	404,000,000
Total	310,000,000	242,000,000
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	5,000,000	5,000,000
Derivative liabilities	269,000,000	171,000,000
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	18,000,000	16,000,000
Derivative liabilities	1,000,000	3,000,000
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	1,000,000	1,000,000
Derivative liabilities	40,000,000	68,000,000
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	90,000,000	72,000,000
Total	177,000,000	53,000,000
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
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
Derivative liabilities	0	0
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	90,000,000	72,000,000
Derivative liabilities	177,000,000	53,000,000
San Diego Gas and Electric Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	607,000,000	619,000,000
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	100,000,000	91,000,000
Nuclear decommissioning trusts - Municipal bonds	161,000,000	156,000,000
Nuclear decommissioning trusts - Other securities	188,000,000	182,000,000
Nuclear decommissioning trusts - Total debt securities	449,000,000	429,000,000
Nuclear decommissioning trusts - Netting	0	0
Total nuclear decommissioning trusts	1,056,000,000	1,048,000,000
Derivative asset netting	18,000,000	28,000,000
Total	1,164,000,000	1,148,000,000
Derivative liability netting	(29,000,000)	(55,000,000)
Total	218,000,000	103,000,000
San Diego Gas and Electric Company [Member] | Commodity contracts not subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,000,000	1,000,000
Derivative asset netting	1,000,000	1,000,000
Derivative liabilities		0
Derivative liability netting		(1,000,000)
San Diego Gas and Electric Company [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	107,000,000	99,000,000
Derivative asset netting	17,000,000	27,000,000
Derivative liabilities	187,000,000	66,000,000
Derivative liability netting	(29,000,000)	(54,000,000)
San Diego Gas and Electric Company [Member] | Interest rate instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	31,000,000	37,000,000
Derivative liability netting	0	0
San Diego Gas and Electric Company [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	607,000,000	619,000,000
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	48,000,000	47,000,000
Nuclear decommissioning trusts - Municipal bonds	0	0
Nuclear decommissioning trusts - Other securities	0	0
Nuclear decommissioning trusts - Total debt securities	48,000,000	47,000,000
Total nuclear decommissioning trusts	655,000,000	666,000,000
Total	655,000,000	666,000,000
Total	0	1,000,000
San Diego Gas and Electric Company [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
Derivative liabilities		1,000,000
San Diego Gas and Electric Company [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	0	0
Derivative liabilities	0	0
San Diego Gas and Electric Company [Member] | Level 1 [Member] | Interest rate instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
San Diego Gas and Electric Company [Member] | Level 2 [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	52,000,000	44,000,000
Nuclear decommissioning trusts - Municipal bonds	161,000,000	156,000,000
Nuclear decommissioning trusts - Other securities	188,000,000	182,000,000
Nuclear decommissioning trusts - Total debt securities	401,000,000	382,000,000
Total nuclear decommissioning trusts	401,000,000	382,000,000
Total	401,000,000	382,000,000
Total	70,000,000	104,000,000
San Diego Gas and Electric Company [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	0	0
Derivative liabilities		0
San Diego Gas and Electric Company [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	0	0
Derivative liabilities	39,000,000	67,000,000
San Diego Gas and Electric Company [Member] | Level 2 [Member] | Interest rate instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	31,000,000	37,000,000
San Diego Gas and Electric Company [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	90,000,000	72,000,000
Total	177,000,000	53,000,000
San Diego Gas and Electric Company [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
Derivative liabilities		0
San Diego Gas and Electric Company [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	90,000,000	72,000,000
Derivative liabilities	177,000,000	53,000,000
San Diego Gas and Electric Company [Member] | Level 3 [Member] | Interest rate instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	0	0
Southern California Gas Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset netting	3,000,000	1,000,000
Total	4,000,000	2,000,000
Derivative liability netting	0	(1,000,000)
Total	2,000,000	1,000,000
Southern California Gas Company [Member] | Commodity contracts not subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,000,000
Derivative asset netting	1,000,000
Derivative liabilities		0
Derivative liability netting		(1,000,000)
Southern California Gas Company [Member] | Commodity contracts subject to rate recovery [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	3,000,000	2,000,000
Derivative asset netting	2,000,000	1,000,000
Derivative liabilities	2,000,000	1,000,000
Derivative liability netting	0	0
Southern California Gas Company [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
Total	1,000,000	1,000,000
Southern California Gas Company [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
Derivative liabilities		1,000,000
Southern California Gas Company [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	0	0
Derivative liabilities	1,000,000	0
Southern California Gas Company [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	1,000,000	1,000,000
Total	1,000,000	1,000,000
Southern California Gas Company [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	0
Derivative liabilities		0
Southern California Gas Company [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	1,000,000	1,000,000
Derivative liabilities	1,000,000	1,000,000
Southern California Gas Company [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0	0
Total	0	0
Southern California Gas Company [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
Derivative liabilities		0
Southern California Gas Company [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
Derivative liabilities	$ 0	$ 0