FAIR VALUE MEASUREMENTS (Details) (USD $) In Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010	Sep. 30, 2011		Sep. 30, 2010	Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Unamortized Discount	$ 14			$ 14			$ 22
Capital Lease Obligations	209			209			221
Commercial Paper Noncurrent	200			200			800
Schedule of Available-for-sale Securities [Line Items]
Cost	553			553			514
Gross unrealized gains	218			218			261
Gross unrealized losses	(11)			(11)			(6)
Estimated fair value	760			760			769
Proceeds from sales	294		97	384		247
Gross realized gains	27		4	29		7
Gross realized losses	(8)		(2)	(10)		(9)
Derivative, Fair Value, Gross Amount Not Offset Against Collateral, Net [Line Items]
Fair value of cash collateral receivables not offset against derivatives	19			19			32
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Nuclear decommissioning trusts - equity securities	427			427			460
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	145			145			174
Nuclear decomissioning trusts - Municipal debt securities	121			121			100
Nuclear decommissioning trusts - Other debt securities	42			42			25
Nuclear decommissioning trusts - Total debt securities	308			308			299
Total nuclear decommissioning trusts	735	[1]		735	[1]		759	[1]
Interest rate instruments, assets	69			69			34
Commodity contracts subject to rate recovery, assets	15			15			28
Commodity contracts not subject to rate recovery, assets	56			56			53
Investments	8			8			1
Total fair value of assets measured on a recurring basis	883			883			875
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, liabilities	122			122			82
Commodity contracts subject to rate recovery, liabilities	8			8			8
Commodity contracts not subject to rate recovery, liabilities	53			53			67
Total fair value of liabilities measured on a recurring basis	183			183			157
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	3		7	2		10
Realized and unrealized gains (losses)	5		(1)	17		(5)
Allocated transmission instruments			7	2		7
Settlements	(5)		(1)	(18)
Balance at end of period	3		12	3		12
San Diego Gas and Electric Company and Subsidiary [Member] | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of financial instruments, Total long-term debt	3,648	[2]		3,648	[2]		3,305	[2]
Fair value of financial instruments, Contingently redeemable preferred stock	79			79			79
Southern California Gas Company [Member] | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of financial instruments, Total long-term debt	1,312	[3]		1,312	[3]		1,566	[3]
Fair value of financial instruments, Preferred stock	22			22			22
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of financial instruments, Investments in affordable housing partnerships	24	[4]		24	[4]		28	[4]
Fair value of financial instruments, Total long-term debt	9,775	[5]		9,775	[5]		8,330	[5]
Fair value of financial instruments, Due to unconsolidated affiliate							2	[6]
Fair value of financial instruments, Preferred stock of subsidiaries	99			99			179
San Diego Gas and Electric Company and Subsidiary [Member] | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of financial instruments, Total long-term debt	3,993	[2]		3,993	[2]		3,300	[2]
Fair value of financial instruments, Contingently redeemable preferred stock	83			83			78
Southern California Gas Company [Member] | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of financial instruments, Total long-term debt	1,494	[3]		1,494	[3]		1,638	[3]
Fair value of financial instruments, Preferred stock	22			22			21
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of financial instruments, Investments in affordable housing partnerships	57	[4]		57	[4]		58	[4]
Fair value of financial instruments, Total long-term debt	11,047	[5]		11,047	[5]		8,883	[5]
Fair value of financial instruments, Due to unconsolidated affiliate							2	[6]
Fair value of financial instruments, Preferred stock of subsidiaries	103			103			166
San Diego Gas and Electric Company and Subsidiary [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Unamortized Discount	11			11			9
Capital Lease Obligations	195			195			202
Derivative, Fair Value, Gross Amount Not Offset Against Collateral, Net [Line Items]
Fair value of cash collateral receivables not offset against derivatives	11			11			25
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Nuclear decommissioning trusts - equity securities	427			427			460
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	145			145			174
Nuclear decomissioning trusts - Municipal debt securities	121			121			100
Nuclear decommissioning trusts - Other debt securities	42			42			25
Nuclear decommissioning trusts - Total debt securities	308			308			299
Total nuclear decommissioning trusts	735	[1]		735	[1]		759	[1]
Commodity contracts subject to rate recovery, assets	14			14			26
Commodity contracts not subject to rate recovery, assets	1			1			2
Total fair value of assets measured on a recurring basis	750			750			787
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, liabilities	79			79			58
Commodity contracts subject to rate recovery, liabilities	5			5			2
Total fair value of liabilities measured on a recurring basis	84			84			60
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	427			427			460
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	84			84			144
Nuclear decommissioning trusts - Total debt securities	84			84			144
Total nuclear decommissioning trusts	511	[1]		511	[1]		604	[1]
Commodity contracts subject to rate recovery, assets	11			11			24
Commodity contracts not subject to rate recovery, assets	1			1			2
Total fair value of assets measured on a recurring basis	523			523			630
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	61			61			30
Nuclear decomissioning trusts - Municipal debt securities	121			121			100
Nuclear decommissioning trusts - Other debt securities	42			42			25
Nuclear decommissioning trusts - Total debt securities	224			224			155
Total nuclear decommissioning trusts	224	[1]		224	[1]		155	[1]
Total fair value of assets measured on a recurring basis	224			224			155
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	3			3			2
Total fair value of assets measured on a recurring basis	3			3			2
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	51			51			60
Total fair value of liabilities measured on a recurring basis	51			51			60
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	79			79			58
Commodity contracts subject to rate recovery, liabilities	5			5			2
Total fair value of liabilities measured on a recurring basis	84			84			60
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	(51)			(51)			(60)
Total fair value of liabilities measured on a recurring basis	(51)			(51)			(60)
Southern California Gas Company [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument Unamortized Discount	2			2			3
Capital Lease Obligations	13			13			19
Derivative, Fair Value, Gross Amount Not Offset Against Collateral, Net [Line Items]
Fair value of cash collateral receivables not offset against derivatives	4			4			3
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, assets							3
Commodity contracts subject to rate recovery, assets	1			1			2
Commodity contracts not subject to rate recovery, assets	2			2			3
Total fair value of assets measured on a recurring basis	3			3			8
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, liabilities	3			3
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	1			1			1
Commodity contracts not subject to rate recovery, assets	2			2			3
Total fair value of assets measured on a recurring basis	3			3			4
Southern California Gas Company [Member] | Level 2
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, assets							3
Commodity contracts subject to rate recovery, assets							1
Total fair value of assets measured on a recurring basis							4
Southern California Gas Company [Member] | Level 1
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, liabilities	2			2
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 Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	283			283			285
Gross unrealized gains	26			26			19
Gross unrealized losses	(1)			(1)			(5)
Estimated fair value	308			308			299
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	128	[7]		128	[7]		162
Gross unrealized gains	17	[7]		17	[7]		14
Gross unrealized losses							(2)
Estimated fair value	145	[7]		145	[7]		174
Municipal Bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	115	[8]		115	[8]		101
Gross unrealized gains	7	[8]		7	[8]		2
Gross unrealized losses	(1)	[8]		(1)	[8]		(3)
Estimated fair value	121	[8]		121	[8]		100
Other Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	40	[9]		40	[9]		22
Gross unrealized gains	2	[9]		2	[9]		3
Estimated fair value	42	[9]		42	[9]		25
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost	245			245			219
Gross unrealized gains	192			192			242
Gross unrealized losses	(10)			(10)			(1)
Estimated fair value	427			427			460
Cash And Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Cost	25			25			10
Estimated fair value	25			25			10
Level 1
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Nuclear decommissioning trusts - equity securities	427			427			460
Nuclear decommissioning trusts - Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies	84			84			144
Nuclear decommissioning trusts - Total debt securities	84			84			144
Total nuclear decommissioning trusts	511	[1]		511	[1]		604	[1]
Commodity contracts subject to rate recovery, assets	12			12			25
Commodity contracts not subject to rate recovery, assets	13			13			9
Investments	8			8			1
Total fair value of assets measured on a recurring basis	544			544			639
Level 1
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, liabilities	53			53			60
Commodity contracts not subject to rate recovery, liabilities	2			2
Total fair value of liabilities measured on a recurring basis	55			55			60
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	61			61			30
Nuclear decomissioning trusts - Municipal debt securities	121			121			100
Nuclear decommissioning trusts - Other debt securities	42			42			25
Nuclear decommissioning trusts - Total debt securities	224			224			155
Total nuclear decommissioning trusts	224	[1]		224	[1]		155	[1]
Interest rate instruments, assets	69			69			34
Commodity contracts subject to rate recovery, assets							1
Commodity contracts not subject to rate recovery, assets	46			46			66
Total fair value of assets measured on a recurring basis	339			339			256
Level 2
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Interest rate instruments, liabilities	122			122			82
Commodity contracts subject to rate recovery, liabilities	6			6			8
Commodity contracts not subject to rate recovery, liabilities	55			55			67
Total fair value of liabilities measured on a recurring basis	183			183			157
Level 3
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, assets	3			3			2
Total fair value of assets measured on a recurring basis	3			3			2
Collateral Netted [Member]
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts not subject to rate recovery, assets	(3)			(3)			(22)
Total fair value of assets measured on a recurring basis	(3)			(3)			(22)
Collateral Netted [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Commodity contracts subject to rate recovery, liabilities	(51)			(51)			(60)
Commodity contracts not subject to rate recovery, liabilities	(4)			(4)
Total fair value of liabilities measured on a recurring basis	$ (55)			$ (55)			$ (60)

[1] Excludes cash balances and cash equivalents.

[2] Before reductions for unamortized discount of $11 million at September 30, 2011 and $9 million at December 31, 2010, and excluding capital leases of $195 million at September 30, 2011 and $202 million at December 31, 2010.

[3] Before reductions for unamortized discount of $2 million at September 30, 2011 and $3 million at December 31, 2010, and excluding capital leases of $13 million at September 30, 2011 and $19 million at December 31, 2010.

[4] We discuss our investments in affordable housing partnerships in Note 4 of the Notes to Consolidated Financial Statements in the Annual Report.

[5] Before reductions for net unamortized discount (premium) of $14 million at September 30, 2011 and $22 million at December 31, 2010, and excluding capital leases of $209 million at September 30, 2011 and $221 million at December 31, 2010, and commercial paper classified as long-term debt of $200 million at September 30, 2011 and $800 million at December 31, 2010. We discuss our long-term debt in Note 6 above and in Note 5 of the Notes to Consolidated Financial Statements in the Annual Report.

[6] Note payable was extinguished due to the increase in our ownership of Chilquinta Energía S.A. to 100% in the second quarter of 2011.

[7] Maturity dates are 2012-2041.

[8] Maturity dates are 2012-2057.

[9] Maturity dates are 2012-2111.