FAIR VALUE MEASUREMENTS 3 (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	$ 529		$ 468
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	146		170
Nuclear decomissioning trusts - Municipal debt securities	66		77
Nuclear decommissioning trusts - Other debt securities	123		78
Nuclear decommissioning trusts - Total debt securities	335		325
Total nuclear decommissioning trusts	864	[1]	793	[1]
Interest rate instruments, assets	73		66
Commodity contracts subject to rate recovery, assets	44		34
Commodity contracts not subject to rate recovery, assets	38		48
Investments	1		5
Total fair value of assets measured on a recurring basis	1,020		946
Interest rate instruments, liabilities	136		125
Commodity contracts subject to rate recovery, liabilities	8		13
Commodity contracts not subject to rate recovery, liabilities	26		49
Total fair value of liabilities measured on a recurring basis	170		187
San Diego Gas and Electric Company and Subsidiary [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	529		468
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	146		170
Nuclear decomissioning trusts - Municipal debt securities	66		77
Nuclear decommissioning trusts - Other debt securities	123		78
Nuclear decommissioning trusts - Total debt securities	335		325
Total nuclear decommissioning trusts	864	[1]	793	[1]
Commodity contracts subject to rate recovery, assets	42		32
Commodity contracts not subject to rate recovery, assets	2		1
Total fair value of assets measured on a recurring basis	908		826
Interest rate instruments, liabilities	85		81
Commodity contracts subject to rate recovery, liabilities	7		12
Total fair value of liabilities measured on a recurring basis	92		93
Southern California Gas Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts subject to rate recovery, assets	2		2
Commodity contracts not subject to rate recovery, assets	2		2
Total fair value of assets measured on a recurring basis	4		4
Commodity contracts subject to rate recovery, liabilities	1		1
Total fair value of liabilities measured on a recurring basis	1		1
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	529		468
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	72		92
Nuclear decommissioning trusts - Total debt securities	72		92
Total nuclear decommissioning trusts	601	[1]	560	[1]
Commodity contracts subject to rate recovery, assets	21		10
Commodity contracts not subject to rate recovery, assets	19		15
Investments	1		5
Total fair value of assets measured on a recurring basis	642		590
Interest rate instruments, liabilities			1
Commodity contracts subject to rate recovery, liabilities	32		61
Commodity contracts not subject to rate recovery, liabilities	9		1
Total fair value of liabilities measured on a recurring basis	41		63
Level 1 | San Diego Gas and Electric Company and Subsidiary [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - equity securities	529		468
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	72		92
Nuclear decommissioning trusts - Total debt securities	72		92
Total nuclear decommissioning trusts	601	[1]	560	[1]
Commodity contracts subject to rate recovery, assets	19		9
Commodity contracts not subject to rate recovery, assets	2		1
Total fair value of assets measured on a recurring basis	622		570
Commodity contracts subject to rate recovery, liabilities	32		61
Total fair value of liabilities measured on a recurring basis	32		61
Level 1 | Southern California Gas Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts subject to rate recovery, assets	2		1
Commodity contracts not subject to rate recovery, assets	2		2
Total fair value of assets measured on a recurring basis	4		3
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	74		78
Nuclear decomissioning trusts - Municipal debt securities	66		77
Nuclear decommissioning trusts - Other debt securities	123		78
Nuclear decommissioning trusts - Total debt securities	263		233
Total nuclear decommissioning trusts	263	[1]	233	[1]
Interest rate instruments, assets	73		66
Commodity contracts subject to rate recovery, assets			1
Commodity contracts not subject to rate recovery, assets	19		35
Total fair value of assets measured on a recurring basis	355		335
Interest rate instruments, liabilities	136		124
Commodity contracts subject to rate recovery, liabilities	8		13
Commodity contracts not subject to rate recovery, liabilities	30		52
Total fair value of liabilities measured on a recurring basis	174		189
Level 2 | San Diego Gas and Electric Company and Subsidiary [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	74		78
Nuclear decomissioning trusts - Municipal debt securities	66		77
Nuclear decommissioning trusts - Other debt securities	123		78
Nuclear decommissioning trusts - Total debt securities	263		233
Total nuclear decommissioning trusts	263	[1]	233	[1]
Total fair value of assets measured on a recurring basis	263		233
Interest rate instruments, liabilities	85		81
Commodity contracts subject to rate recovery, liabilities	7		12
Total fair value of liabilities measured on a recurring basis	92		93
Level 2 | Southern California Gas Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts subject to rate recovery, assets			1
Total fair value of assets measured on a recurring basis			1
Commodity contracts subject to rate recovery, liabilities	1		1
Total fair value of liabilities measured on a recurring basis	1		1
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts subject to rate recovery, assets	23		23
Total fair value of assets measured on a recurring basis	23		23
Level 3 | San Diego Gas and Electric Company and Subsidiary [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts subject to rate recovery, assets	23		23
Total fair value of assets measured on a recurring basis	23		23
Collateral Netted [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts not subject to rate recovery, assets			(2)
Total fair value of assets measured on a recurring basis			(2)
Commodity contracts subject to rate recovery, liabilities	(32)		(61)
Commodity contracts not subject to rate recovery, liabilities	(13)		(4)
Total fair value of liabilities measured on a recurring basis	(45)		(65)
Collateral Netted [Member] | San Diego Gas and Electric Company and Subsidiary [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commodity contracts subject to rate recovery, liabilities	(32)		(61)
Total fair value of liabilities measured on a recurring basis	$ (32)		$ (61)

[1] Excludes cash balances and cash equivalents.