CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Current portion of long-term debt and finance leases	$ 2,152	$ 1,644	[1]
Property, plant and equipment, net	34,698	34,439	[1]
Long-term debt and finance leases	$ 19,738	$ 20,903	[1]
Stockholders' Equity Attributable to Parent [Abstract]
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares authorized (in shares)	750,000,000	750,000,000
Common stock, shares outstanding (in shares)	274,000,000	274,000,000
Otay Mesa VIE [Member]
Current portion of long-term debt and finance leases	$ 36	$ 28
Property, plant and equipment, net	287	295
Long-term debt and finance leases	182	190
San Diego Gas and Electric Company [Member]
Current portion of long-term debt and finance leases	89	81	[1]
Property, plant and equipment, net	16,464	16,310	[1]
Long-term debt and finance leases	$ 6,113	$ 6,138	[1]
Stockholders' Equity Attributable to Parent [Abstract]
Preferred stock, shares authorized (in shares)	45,000,000	45,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, shares authorized (in shares)	255,000,000	255,000,000
Common stock, shares outstanding (in shares)	117,000,000	117,000,000
San Diego Gas and Electric Company [Member] | Otay Mesa VIE [Member]
Current portion of long-term debt and finance leases	$ 36	$ 28
Property, plant and equipment, net	287	295
Long-term debt and finance leases	182	190
Southern California Gas Company [Member]
Current portion of long-term debt and finance leases	3	3	[1]
Property, plant and equipment, net	12,581	12,439	[1]
Long-term debt and finance leases	$ 3,429	$ 3,427	[1]
Stockholders' Equity Attributable to Parent [Abstract]
Preferred stock, shares authorized (in shares)	11,000,000	11,000,000
Preferred stock, shares issued (in shares)	1,000,000	1,000,000
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares outstanding (in shares)	91,000,000	91,000,000
Convertible Preferred Stock Series A [Member]
Stockholders' Equity Attributable to Parent [Abstract]
Preferred Stock, Dividend Rate, Percentage	6.00%	6.00%
Preferred stock, shares issued (in shares)	17,250,000	17,250,000
Preferred stock, shares outstanding (in shares)	17,250,000	17,250,000
Convertible Preferred Stock Series B [Member]
Stockholders' Equity Attributable to Parent [Abstract]
Preferred Stock, Dividend Rate, Percentage	6.75%	6.75%
Preferred stock, shares issued (in shares)	5,750,000	5,750,000
Preferred stock, shares outstanding (in shares)	5,750,000	5,750,000

[1] Derived from audited financial statements.