FAIR VALUE MEASUREMENTS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 572			$ 562
Gross unrealized gains	296			248
Gross unrealized losses	(3)			(6)
Estimated fair value	865			804
Proceeds from sales	129		42
Gross realized gains	4		1
Gross realized losses			(1)
Derivative, Fair Value, Gross Amount Not Offset Against Collateral, Net [Line Items]
Fair value of cash collateral receivables not offset against derivatives	25			20
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Nuclear decommissioning trusts - equity securities	515			468
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	171			170
Nuclear decomissioning trusts - Municipal debt securities	70			77
Nuclear decommissioning trusts - Other debt securities	84			78
Nuclear decommissioning trusts - Total debt securities	325			325
Total nuclear decommissioning trusts	840	[1]		793	[1]
Interest rate instruments, assets	65			66
Commodity contracts subject to rate recovery, assets	34			34
Commodity contracts not subject to rate recovery, assets	43			48
Investments	1			5
Total fair value of assets measured on a recurring basis	983			946
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, liabilities	116			125
Commodity contracts subject to rate recovery, liabilities	17			13
Commodity contracts not subject to rate recovery, liabilities	42			49
Total fair value of liabilities measured on a recurring basis	175			187
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	23		2
Realized and unrealized gains (losses)	2		6
Allocated transmission instruments	1		1
Settlements	(5)		(6)
Balance at end of period	21		3
CRR Auction Rate Per MWh, Minimum	(3)
CRR Auction Rate Per MWh, Maximum	5
Level 1
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, liabilities				1
Commodity contracts subject to rate recovery, liabilities	69			61
Commodity contracts not subject to rate recovery, liabilities				1
Total fair value of liabilities measured on a recurring basis	69			63
Level 2
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, liabilities	116			124
Commodity contracts subject to rate recovery, liabilities	17			13
Commodity contracts not subject to rate recovery, liabilities	45			52
Total fair value of liabilities measured on a recurring basis	178			189
Collateral Netted [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, liabilities	(69)			(61)
Commodity contracts not subject to rate recovery, liabilities	(3)			(4)
Total fair value of liabilities measured on a recurring basis	(72)			(65)
Level 1
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Nuclear decommissioning trusts - equity securities	515			468
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	91			92
Nuclear decommissioning trusts - Total debt securities	91			92
Total nuclear decommissioning trusts	606	[1]		560	[1]
Commodity contracts subject to rate recovery, assets	13			10
Commodity contracts not subject to rate recovery, assets	13			15
Investments	1			5
Total fair value of assets measured on a recurring basis	633			590
Level 2
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	80			78
Nuclear decomissioning trusts - Municipal debt securities	70			77
Nuclear decommissioning trusts - Other debt securities	84			78
Nuclear decommissioning trusts - Total debt securities	234			233
Total nuclear decommissioning trusts	234	[1]		233	[1]
Interest rate instruments, assets	65			66
Commodity contracts subject to rate recovery, assets				1
Commodity contracts not subject to rate recovery, assets	30			35
Total fair value of assets measured on a recurring basis	329			335
Level 3
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, assets	21			23
Total fair value of assets measured on a recurring basis	21			23
Collateral Netted [Member]
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts not subject to rate recovery, assets				(2)
Total fair value of assets measured on a recurring basis				(2)
San Diego Gas and Electric Company and Subsidiary [Member]
Derivative, Fair Value, Gross Amount Not Offset Against Collateral, Net [Line Items]
Fair value of cash collateral receivables not offset against derivatives	12			10
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Nuclear decommissioning trusts - equity securities	515			468
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	171			170
Nuclear decomissioning trusts - Municipal debt securities	70			77
Nuclear decommissioning trusts - Other debt securities	84			78
Nuclear decommissioning trusts - Total debt securities	325			325
Total nuclear decommissioning trusts	840	[1]		793	[1]
Commodity contracts subject to rate recovery, assets	32			32
Commodity contracts not subject to rate recovery, assets	1			1
Total fair value of assets measured on a recurring basis	873			826
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, liabilities	77			81
Commodity contracts subject to rate recovery, liabilities	16			12
Total fair value of liabilities measured on a recurring basis	93			93
San Diego Gas and Electric Company and Subsidiary [Member] | Level 1
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, liabilities	69			61
Total fair value of liabilities measured on a recurring basis	69			61
San Diego Gas and Electric Company and Subsidiary [Member] | Level 2
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, liabilities	77			81
Commodity contracts subject to rate recovery, liabilities	16			12
Total fair value of liabilities measured on a recurring basis	93			93
San Diego Gas and Electric Company and Subsidiary [Member] | Collateral Netted [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, liabilities	(69)			(61)
Total fair value of liabilities measured on a recurring basis	(69)			(61)
San Diego Gas and Electric Company and Subsidiary [Member] | Level 1
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Nuclear decommissioning trusts - equity securities	515			468
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	91			92
Nuclear decommissioning trusts - Total debt securities	91			92
Total nuclear decommissioning trusts	606	[1]		560	[1]
Commodity contracts subject to rate recovery, assets	11			9
Commodity contracts not subject to rate recovery, assets	1			1
Total fair value of assets measured on a recurring basis	618			570
San Diego Gas and Electric Company and Subsidiary [Member] | Level 2
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	80			78
Nuclear decomissioning trusts - Municipal debt securities	70			77
Nuclear decommissioning trusts - Other debt securities	84			78
Nuclear decommissioning trusts - Total debt securities	234			233
Total nuclear decommissioning trusts	234	[1]		233	[1]
Total fair value of assets measured on a recurring basis	234			233
San Diego Gas and Electric Company and Subsidiary [Member] | Level 3
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, assets	21			23
Total fair value of assets measured on a recurring basis	21			23
Southern California Gas Company [Member]
Derivative, Fair Value, Gross Amount Not Offset Against Collateral, Net [Line Items]
Fair value of cash collateral receivables not offset against derivatives	3			2
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [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
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, liabilities	1			1
Total fair value of liabilities measured on a recurring basis	1			1
Southern California Gas Company [Member] | Level 2
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, liabilities	1			1
Total fair value of liabilities measured on a recurring basis	1			1
Southern California Gas Company [Member] | Level 1
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [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
Southern California Gas Company [Member] | Level 2
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, assets				1
Total fair value of assets measured on a recurring basis				1
Total Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	308			305
Gross unrealized gains	18			21
Gross unrealized losses	(1)			(1)
Estimated fair value	325			325
Debt Securities Issued By The U.S. Treasury And Other U.S. Government Corporations And Agencies
Schedule of Available-for-sale Securities [Line Items]
Cost	162	[2]		157
Gross unrealized gains	9	[2]		13
Estimated fair value	171	[2]		170
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	66	[3]		72
Gross unrealized gains	5	[3]		5
Gross unrealized losses	(1)	[3]
Estimated fair value	70	[3]		77
Other Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	80	[4]		76
Gross unrealized gains	4	[4]		3
Gross unrealized losses				(1)
Estimated fair value	84	[4]		78
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	239			246
Gross unrealized gains	278			227
Gross unrealized losses	(2)			(5)
Estimated fair value	515			468
Cash And Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Cost	25			11
Estimated fair value	$ 25			$ 11

[1] Excludes cash balances and cash equivalents.

[2] Maturity dates are 2013-2042

[3] Maturity dates are 2012-2057

[4] Maturity dates are 2012-2051