OTHER FINANCIAL DATA - INVENTORY (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Inventory [Line Items]
Energy Related Inventory, Natural Gas in Storage	$ 239	$ 195
Energy Related Inventory, Materials And Supplies	159	151
Inventory, Total	398	346	[1],[2]
S D G E Segment [Member]
Inventory [Line Items]
Energy Related Inventory, Natural Gas in Storage	2	6
Energy Related Inventory, Materials And Supplies	81	76
Inventory, Total	83	82
So Cal Gas Segment [Member]
Inventory [Line Items]
Energy Related Inventory, Natural Gas in Storage	142	128
Energy Related Inventory, Materials And Supplies	24	23
Inventory, Total	166	151
Sempra South American Utilities Segment [Member]
Inventory [Line Items]
Energy Related Inventory, Materials And Supplies	37	36
Inventory, Total	37	36
Sempra Mexico Segment [Member]
Inventory [Line Items]
Energy Related Inventory, Natural Gas in Storage	10	10
Energy Related Inventory, Materials And Supplies	8	7
Inventory, Total	18	17
Sempra Natural Gas Segment [Member]
Inventory [Line Items]
Energy Related Inventory, Natural Gas in Storage	85	51
Energy Related Inventory, Materials And Supplies	9	9
Inventory, Total	$ 94	$ 60

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

[2] Derived from audited financial statements.