OTHER FINANCIAL DATA - OTHER INCOME (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	$ 44		$ 12	[1]	$ 137		$ 86	[1]
San Diego Gas and Electric Company and Subsidiary [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	5		26		59		55
Southern California Gas Company [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	6		3		14		9
Allowance for Cost of Equity Funds Used During Construction [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	13		26		80		67
Allowance for Cost of Equity Funds Used During Construction [Member] | San Diego Gas and Electric Company and Subsidiary [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	6		21		61		54
Allowance for Cost of Equity Funds Used During Construction [Member] | Southern California Gas Company [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	7		5		19		13
Regulatory Interest, Net [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net			0	[2]	1	[2]	1	[2]
Regulatory Interest, Net [Member] | San Diego Gas and Electric Company and Subsidiary [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net			0	[2]	1	[2]	1	[2]
Gains (losses) on interest rate and foreign exchange instruments [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	1		(26)		11		(14)
Gain (Loss) on Investments [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	17	[3]	(6)	[3]	27	[3]	13	[3]
Other Income, Sundry [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	13		18		18		19
Other Income, Sundry [Member] | San Diego Gas and Electric Company and Subsidiary [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	(1)		5		(3)		0
Other Income, Sundry [Member] | Southern California Gas Company [Member]
Component of Other Income, Nonoperating [Line Items]
Other income (expense), net	$ (1)		$ (2)		$ (5)		$ (4)

[1] As adjusted for the retrospective effect of a change in accounting principle as we discuss in Note 1.

[2] Interest on regulatory balancing accounts.

[3] Represents investment gains (losses) on dedicated assets in support of our executive retirement and deferred compensation plans. These amounts are partially offset by corresponding changes in compensation expense related to the plans.