CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Net income	$ 351	$ 1,519	[1]	$ 1,448	[1]
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Total other comprehensive income (loss)	142	52		(334)
Preferred dividends of subsidiary	(1)	(1)		(1)
Pretax amount [Member]
Net income	1,533	1,760		1,691
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments	107	42		(260)
Financial instruments	2	(6)		(80)
Pension and other postretirement benefits	20	(13)		(3)
Total other comprehensive income (loss)	129	23		(343)
Comprehensive income	1,662	1,783		1,348
Preferred dividends of subsidiary	(1)	(1)		(1)
Total comprehensive income, after preferred dividends of subsidiaries	1,661	1,782		1,347
Income tax (expense) benefit [Member]
Net income	(1,276)	(389)		(341)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments	0	0		0
Financial instruments	1	11		33
Pension and other postretirement benefits	(8)	4		1
Total other comprehensive income (loss)	(7)	15		34
Comprehensive income	(1,283)	(374)		(307)
Preferred dividends of subsidiary	0	0		0
Total comprehensive income, after preferred dividends of subsidiaries	(1,283)	(374)		(307)
Net-of-tax amount [Member]
Net income	257	1,371		1,350
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments	107	42		(260)
Financial instruments	3	5		(47)
Pension and other postretirement benefits	12	(9)		(2)
Total other comprehensive income (loss)	122	38		(309)
Comprehensive income	379	1,409		1,041
Preferred dividends of subsidiary	(1)	(1)		(1)
Total comprehensive income, after preferred dividends of subsidiaries	378	1,408		1,040
Noncontrolling interests (after-tax) [Member]
Net income	94	148		98
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments	8	(3)		(30)
Financial instruments	12	17		5
Pension and other postretirement benefits	0	0		0
Total other comprehensive income (loss)	20	14		(25)
Comprehensive income	114	162		73
Preferred dividends of subsidiary	0	0		0
Total comprehensive income, after preferred dividends of subsidiaries	114	162		73
Total [Member]
Net income	351	1,519		1,448
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments	115	39		(290)
Financial instruments	15	22		(42)
Pension and other postretirement benefits	12	(9)		(2)
Total other comprehensive income (loss)	142	52		(334)
Comprehensive income	493	1,571		1,114
Preferred dividends of subsidiary	(1)	(1)		(1)
Total comprehensive income, after preferred dividends of subsidiaries	492	1,570		1,113
San Diego Gas and Electric Company [Member]
Net income	421	565	[1]	606	[1]
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Total other comprehensive income (loss)	11	10		10
San Diego Gas and Electric Company [Member] | Pretax amount [Member]
Net income	562	850		871
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Financial instruments	0	0		0
Pension and other postretirement benefits	(1)			7
Total other comprehensive income (loss)	(1)	0		7
Comprehensive income	561	850		878
San Diego Gas and Electric Company [Member] | Income tax (expense) benefit [Member]
Net income	(155)	(280)		(284)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Financial instruments	0	0		0
Pension and other postretirement benefits	1			(3)
Total other comprehensive income (loss)	1	0		(3)
Comprehensive income	(154)	(280)		(287)
San Diego Gas and Electric Company [Member] | Net-of-tax amount [Member]
Net income	407	570		587
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Financial instruments	0	0		0
Pension and other postretirement benefits	0			4
Total other comprehensive income (loss)	0	0		4
Comprehensive income	407	570		591
San Diego Gas and Electric Company [Member] | Noncontrolling interests (after-tax) [Member]
Net income	14	(5)		19
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Financial instruments	11	10		6
Pension and other postretirement benefits	0			0
Total other comprehensive income (loss)	11	10		6
Comprehensive income	25	5		25
San Diego Gas and Electric Company [Member] | Total [Member]
Net income	421	565		606
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Financial instruments	11	10		6
Pension and other postretirement benefits	0			4
Total other comprehensive income (loss)	11	10		10
Comprehensive income	432	575		616
Southern California Gas Company [Member]
Net income	397	350		420
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Total other comprehensive income (loss)	1	(3)		(1)
Southern California Gas Company [Member] | Pretax amount [Member]
Net income	557	493		558
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Financial instruments		1		1
Pension and other postretirement benefits	1	(6)		(2)
Total other comprehensive income (loss)	1	(5)		(1)
Comprehensive income	558	488		557
Southern California Gas Company [Member] | Income tax (expense) benefit [Member]
Net income	(160)	(143)		(138)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Financial instruments		0		(1)
Pension and other postretirement benefits	0	2		1
Total other comprehensive income (loss)	0	2		0
Comprehensive income	(160)	(141)		(138)
Southern California Gas Company [Member] | Net-of-tax amount [Member]
Net income	397	350		420
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Financial instruments		1		0
Pension and other postretirement benefits	1	(4)		(1)
Total other comprehensive income (loss)	1	(3)		(1)
Comprehensive income	$ 398	$ 347		$ 419

[1] As adjusted for the retrospective adoption of ASU 2016-15 and ASU 2016-18, which we discuss in Note 2.