EMPLOYEE BENEFIT PLANS - EMPLOYEE BENEFIT PLANS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Liability, Defined Benefit Plan [Abstract]
Noncurrent liabilities	$ (1,161,000,000)	$ (1,148,000,000)
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	7.00%
Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	$ 3,857,000,000	3,679,000,000
Service cost	124,000,000	117,000,000	$ 107,000,000
Interest cost	141,000,000	151,000,000	160,000,000
Contributions from plan participants	0	0
Actuarial (gain) loss	(269,000,000)	286,000,000
Plan amendments	12,000,000	1,000,000
Benefit payments	(115,000,000)	(182,000,000)
Special termination benefits	0	0
Acquisition	0	0
Curtailments	0	(1,000,000)
Settlements	(394,000,000)	(194,000,000)	(75,000,000)
Ending balance	3,356,000,000	3,857,000,000	3,679,000,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Actual return on plan assets	(180,000,000)	421,000,000
Employer contributions	190,000,000	155,000,000
Contributions from plan participants	0	0
Benefit payments	(115,000,000)	(182,000,000)
Settlements	(394,000,000)	(194,000,000)
Ending balance	2,160,000,000	2,659,000,000	2,459,000,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	(1,196,000,000)	(1,198,000,000)
Net recorded (liability) asset at December 31	(1,196,000,000)	(1,198,000,000)
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	0	0
Current liabilities	(65,000,000)	(69,000,000)
Noncurrent liabilities	(1,131,000,000)	(1,129,000,000)
Net recorded (liability) asset	(1,196,000,000)	(1,198,000,000)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]
Net actuarial (loss) gain	(114,000,000)	(84,000,000)
Prior service cost	(12,000,000)	(4,000,000)
Total	(126,000,000)	(88,000,000)
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	3,130,000,000	3,623,000,000
Accumulated benefit obligation	2,894,000,000	3,334,000,000
Fair value of plan assets	2,160,000,000	2,659,000,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	124,000,000	117,000,000	107,000,000
Interest cost	141,000,000	151,000,000	160,000,000
Expected return on assets	(157,000,000)	(161,000,000)	(166,000,000)
Amortization of Prior service cost (credit)	11,000,000	11,000,000	11,000,000
Amortization of actuarial loss (gain)	23,000,000	36,000,000	30,000,000
Settlement charges	66,000,000	38,000,000	16,000,000
Special termination benefits	0	0	0
Net periodic benefit cost	208,000,000	192,000,000	158,000,000
Regulatory adjustment	(30,000,000)	(42,000,000)	(57,000,000)
Total expense recognized	178,000,000	150,000,000	101,000,000
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net loss (gain)	56,000,000	0	26,000,000
Prior service cost	12,000,000	1,000,000	0
Amortization of actuarial loss	(12,000,000)	(10,000,000)	(10,000,000)
Amortization of prior service cost	(2,000,000)	(1,000,000)	(1,000,000)
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	(12,000,000)	(8,000,000)	0
Total recognized in OCI	42,000,000	(18,000,000)	15,000,000
Total recognized in net periodic benefit cost and OCI	$ 220,000,000	$ 132,000,000	$ 116,000,000
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.30%	3.65%
Interest crediting rate	3.36%	2.80%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.65%	4.08%	4.46%
Expected return on plan assets	7.00%	7.00%	7.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Interest Crediting Rate	2.80%	2.86%	3.03%
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
Expected employer contributions	$ 228,000,000
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2019	416,000,000
2020	270,000,000
2021	268,000,000
2022	246,000,000
2023	236,000,000
2024-2028	$ 1,097,000,000
Pension Plan [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	10.00%	10.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	10.00%	10.00%	10.00%
Pension Plan [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	2.00%	2.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	2.00%	2.00%	2.00%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	$ 963,000,000	$ 922,000,000
Service cost	21,000,000	21,000,000	$ 20,000,000
Interest cost	36,000,000	39,000,000	42,000,000
Contributions from plan participants	23,000,000	20,000,000
Actuarial (gain) loss	(123,000,000)	6,000,000
Plan amendments	0	0
Benefit payments	(74,000,000)	(63,000,000)
Special termination benefits	5,000,000	18,000,000	26,000,000
Acquisition	21,000,000	0
Curtailments	0	0
Settlements	0	0
Ending balance	872,000,000	963,000,000	922,000,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Actual return on plan assets	(56,000,000)	185,000,000
Employer contributions	6,000,000	10,000,000
Contributions from plan participants	23,000,000	20,000,000
Benefit payments	(74,000,000)	(63,000,000)
Settlements	0	0
Ending balance	1,108,000,000	1,209,000,000	1,057,000,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	236,000,000	246,000,000
Net recorded (liability) asset at December 31	236,000,000	246,000,000
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	272,000,000	266,000,000
Current liabilities	(6,000,000)	(1,000,000)
Noncurrent liabilities	(30,000,000)	(19,000,000)
Net recorded (liability) asset	236,000,000	246,000,000
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]
Net actuarial (loss) gain	8,000,000	4,000,000
Prior service cost	0	0
Total	8,000,000	4,000,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	21,000,000	21,000,000	20,000,000
Interest cost	36,000,000	39,000,000	42,000,000
Expected return on assets	(70,000,000)	(66,000,000)	(69,000,000)
Amortization of Prior service cost (credit)	1,000,000	1,000,000	0
Amortization of actuarial loss (gain)	(6,000,000)	(4,000,000)	(1,000,000)
Settlement charges	0	0	0
Special termination benefits	5,000,000	18,000,000	26,000,000
Net periodic benefit cost	(13,000,000)	9,000,000	18,000,000
Regulatory adjustment	17,000,000	0	(11,000,000)
Total expense recognized	4,000,000	9,000,000	7,000,000
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net loss (gain)	(4,000,000)	(2,000,000)	(2,000,000)
Prior service cost	0	0	0
Amortization of actuarial loss	0	0	0
Amortization of prior service cost	0	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	0	0	0
Total recognized in OCI	(4,000,000)	(2,000,000)	(2,000,000)
Total recognized in net periodic benefit cost and OCI	$ 0	$ 7,000,000	$ 5,000,000
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.30%	3.70%
Interest crediting rate	3.36%	2.80%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.70%	4.19%	4.49%
Expected return on plan assets	6.49%	6.47%	6.98%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Interest Crediting Rate	2.80%	2.86%	3.03%
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
Expected employer contributions	$ 10,000,000
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2019	54,000,000
2020	51,000,000
2021	52,000,000
2022	52,000,000
2023	52,000,000
2024-2028	$ 257,000,000
Other Postretirement Benefits Plan [Member] | Pre-65Retiree [Member]
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health care cost trend rate assumed for next year	6.50%	7.00%	8.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend)	4.75%	5.00%	5.00%
Other Postretirement Benefits Plan [Member] | Retiree Aged 65 or Older [Member]
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health care cost trend rate assumed for next year	4.75%	5.00%	5.50%
Rate to which the cost trend rate is assumed to decline (the ultimate trend)	4.50%	4.50%	4.50%
Other Postretirement Benefits Plan [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	10.00%	10.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	10.00%	10.00%	10.00%
Other Postretirement Benefits Plan [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	2.00%	2.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	2.00%	2.00%	2.00%
Southern California Gas Company [Member] | Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	$ 2,486,000,000	$ 2,343,000,000
Service cost	81,000,000	76,000,000	$ 67,000,000
Interest cost	92,000,000	98,000,000	101,000,000
Contributions from plan participants	0	0
Actuarial (gain) loss	(215,000,000)	216,000,000
Benefit payments	(65,000,000)	(73,000,000)
Special termination benefits	0	0
Settlements	(231,000,000)	(175,000,000)
Transfer of liability from other plans	0	1,000,000
Ending balance	2,148,000,000	2,486,000,000	2,343,000,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Actual return on plan assets	(117,000,000)	269,000,000
Employer contributions	104,000,000	93,000,000
Contributions from plan participants	0	0
Benefit payments	(65,000,000)	(73,000,000)
Settlements	(231,000,000)	(175,000,000)
Transfer of assets from other plans	0	1,000,000
Ending balance	1,385,000,000	1,694,000,000	1,579,000,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	(763,000,000)	(792,000,000)
Net recorded (liability) asset at December 31	(763,000,000)	(792,000,000)
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	0	0
Current liabilities	(3,000,000)	(3,000,000)
Noncurrent liabilities	(760,000,000)	(789,000,000)
Net recorded (liability) asset	(763,000,000)	(792,000,000)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]
Net actuarial (loss) gain	(6,000,000)	(6,000,000)
Prior service cost	(2,000,000)	(2,000,000)
Total	(8,000,000)	(8,000,000)
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	2,123,000,000	2,462,000,000
Accumulated benefit obligation	1,919,000,000	2,220,000,000
Fair value of plan assets	1,385,000,000	1,694,000,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	81,000,000	76,000,000	67,000,000
Interest cost	92,000,000	98,000,000	101,000,000
Expected return on assets	(98,000,000)	(103,000,000)	(103,000,000)
Amortization of Prior service cost (credit)	8,000,000	9,000,000	9,000,000
Amortization of actuarial loss (gain)	13,000,000	19,000,000	11,000,000
Settlement charges	32,000,000	30,000,000	0
Special termination benefits	0	0	0
Net periodic benefit cost	128,000,000	129,000,000	85,000,000
Regulatory adjustment	(22,000,000)	(34,000,000)	(12,000,000)
Total expense recognized	106,000,000	95,000,000	73,000,000
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net loss (gain)	1,000,000	0	4,000,000
Prior service cost	0	0	2,000,000
Amortization of prior service cost	(1,000,000)	(1,000,000)	0
Total recognized in OCI	0	(1,000,000)	6,000,000
Total recognized in net periodic benefit cost and OCI	$ 106,000,000	$ 94,000,000	$ 79,000,000
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.30%	3.65%
Interest crediting rate	3.36%	2.80%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.65%	4.10%	4.50%
Expected return on plan assets	7.00%	7.00%	7.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Interest Crediting Rate	2.80%	2.86%	3.03%
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
Expected employer contributions	$ 118,000,000
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2019	207,000,000
2020	159,000,000
2021	154,000,000
2022	152,000,000
2023	149,000,000
2024-2028	$ 698,000,000
Southern California Gas Company [Member] | Pension Plan [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	10.00%	10.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	10.00%	10.00%	10.00%
Southern California Gas Company [Member] | Pension Plan [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	2.00%	2.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	2.00%	2.00%	2.00%
Southern California Gas Company [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	$ 737,000,000	$ 691,000,000
Service cost	15,000,000	14,000,000	$ 14,000,000
Interest cost	27,000,000	29,000,000	32,000,000
Contributions from plan participants	14,000,000	13,000,000
Actuarial (gain) loss	(100,000,000)	16,000,000
Benefit payments	(49,000,000)	(44,000,000)
Special termination benefits	2,000,000	18,000,000	11,000,000
Settlements	0	0
Transfer of liability from other plans	0	0
Ending balance	646,000,000	737,000,000	691,000,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Actual return on plan assets	(43,000,000)	151,000,000
Employer contributions	1,000,000	3,000,000
Contributions from plan participants	14,000,000	13,000,000
Benefit payments	(49,000,000)	(44,000,000)
Settlements	0	0
Transfer of assets from other plans	0	0
Ending balance	916,000,000	993,000,000	870,000,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	270,000,000	256,000,000
Net recorded (liability) asset at December 31	270,000,000	256,000,000
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	270,000,000	256,000,000
Current liabilities	0	0
Noncurrent liabilities	0	0
Net recorded (liability) asset	270,000,000	256,000,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	15,000,000	14,000,000	14,000,000
Interest cost	27,000,000	29,000,000	32,000,000
Expected return on assets	(56,000,000)	(53,000,000)	(56,000,000)
Amortization of Prior service cost (credit)	(3,000,000)	(3,000,000)	(4,000,000)
Amortization of actuarial loss (gain)	(2,000,000)	(3,000,000)	0
Settlement charges	0	0	0
Special termination benefits	2,000,000	18,000,000	11,000,000
Net periodic benefit cost	(17,000,000)	2,000,000	(3,000,000)
Regulatory adjustment	17,000,000	0	3,000,000
Total expense recognized	0	2,000,000	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net loss (gain)	0	0	0
Prior service cost	0	0	0
Amortization of prior service cost	0	0	0
Total recognized in OCI	0	0	0
Total recognized in net periodic benefit cost and OCI	$ 0	$ 2,000,000	$ 0
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.30%	3.70%
Interest crediting rate	3.36%	2.80%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.70%	4.20%	4.50%
Expected return on plan assets	6.38%	6.37%	7.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Interest Crediting Rate	2.80%	2.86%	3.03%
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
Expected employer contributions	$ 1,000,000
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2019	36,000,000
2020	36,000,000
2021	37,000,000
2022	37,000,000
2023	38,000,000
2024-2028	$ 187,000,000
Southern California Gas Company [Member] | Other Postretirement Benefits Plan [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	10.00%	10.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	10.00%	10.00%	10.00%
Southern California Gas Company [Member] | Other Postretirement Benefits Plan [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	2.00%	2.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	2.00%	2.00%	2.00%
San Diego Gas and Electric Company [Member]
Liability, Defined Benefit Plan [Abstract]
Noncurrent liabilities	$ (212,000,000)	$ (182,000,000)
San Diego Gas and Electric Company [Member] | Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	971,000,000	935,000,000
Service cost	30,000,000	29,000,000	$ 29,000,000
Interest cost	35,000,000	38,000,000	41,000,000
Contributions from plan participants	0	0
Actuarial (gain) loss	(63,000,000)	50,000,000
Plan amendments	8,000,000	0
Benefit payments	(22,000,000)	(83,000,000)
Special termination benefits	0	0
Settlements	(145,000,000)	0	(75,000,000)
Transfer of liability from other plans	0	2,000,000
Ending balance	814,000,000	971,000,000	935,000,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Actual return on plan assets	(56,000,000)	120,000,000
Employer contributions	47,000,000	22,000,000
Contributions from plan participants	0	0
Benefit payments	(22,000,000)	(83,000,000)
Settlements	(145,000,000)	0
Transfer of assets from other plans	0	3,000,000
Ending balance	600,000,000	776,000,000	714,000,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	(214,000,000)	(195,000,000)
Net recorded (liability) asset at December 31	(214,000,000)	(195,000,000)
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	0	0
Current liabilities	(2,000,000)	(13,000,000)
Noncurrent liabilities	(212,000,000)	(182,000,000)
Net recorded (liability) asset	(214,000,000)	(195,000,000)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]
Net actuarial (loss) gain	(4,000,000)	(8,000,000)
Prior service cost	(6,000,000)	0
Total	(10,000,000)	(8,000,000)
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	788,000,000	939,000,000
Accumulated benefit obligation	762,000,000	900,000,000
Fair value of plan assets	600,000,000	776,000,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	30,000,000	29,000,000	29,000,000
Interest cost	35,000,000	38,000,000	41,000,000
Expected return on assets	(47,000,000)	(47,000,000)	(49,000,000)
Amortization of Prior service cost (credit)	2,000,000	1,000,000	1,000,000
Amortization of actuarial loss (gain)	1,000,000	9,000,000	10,000,000
Settlement charges	26,000,000	0	16,000,000
Special termination benefits	0	0	0
Net periodic benefit cost	47,000,000	30,000,000	48,000,000
Regulatory adjustment	(8,000,000)	(8,000,000)	(45,000,000)
Total expense recognized	39,000,000	22,000,000	3,000,000
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net loss (gain)	(1,000,000)	2,000,000	1,000,000
Prior service cost	8,000,000	0	0
Amortization of actuarial loss	(1,000,000)	(1,000,000)	(1,000,000)
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	(4,000,000)	0	0
Total recognized in OCI	2,000,000	1,000,000	0
Total recognized in net periodic benefit cost and OCI	$ 41,000,000	$ 23,000,000	$ 3,000,000
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.29%	3.64%
Interest crediting rate	3.36%	2.80%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.64%	4.08%	4.35%
Expected return on plan assets	7.00%	7.00%	7.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Interest Crediting Rate	2.80%	2.86%	3.03%
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
Expected employer contributions	$ 40,000,000
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2019	109,000,000
2020	69,000,000
2021	64,000,000
2022	61,000,000
2023	62,000,000
2024-2028	$ 282,000,000
San Diego Gas and Electric Company [Member] | Pension Plan [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	10.00%	10.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	10.00%	10.00%	10.00%
San Diego Gas and Electric Company [Member] | Pension Plan [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	2.00%	2.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	2.00%	2.00%	2.00%
San Diego Gas and Electric Company [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	$ 185,000,000	$ 190,000,000
Service cost	5,000,000	5,000,000	$ 5,000,000
Interest cost	7,000,000	8,000,000	7,000,000
Contributions from plan participants	8,000,000	7,000,000
Actuarial (gain) loss	(17,000,000)	(9,000,000)
Plan amendments	0	0
Benefit payments	(21,000,000)	(16,000,000)
Special termination benefits	3,000,000	0	14,000,000
Settlements	0	0
Transfer of liability from other plans	0	0
Ending balance	170,000,000	185,000,000	190,000,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Actual return on plan assets	(12,000,000)	30,000,000
Employer contributions	2,000,000	5,000,000
Contributions from plan participants	8,000,000	7,000,000
Benefit payments	(21,000,000)	(16,000,000)
Settlements	0	0
Transfer of assets from other plans	0	0
Ending balance	172,000,000	195,000,000	169,000,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	2,000,000	10,000,000
Net recorded (liability) asset at December 31	2,000,000	10,000,000
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	2,000,000	10,000,000
Current liabilities	0	0
Noncurrent liabilities	0	0
Net recorded (liability) asset	2,000,000	10,000,000
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	5,000,000	5,000,000	5,000,000
Interest cost	7,000,000	8,000,000	7,000,000
Expected return on assets	(13,000,000)	(11,000,000)	(12,000,000)
Amortization of Prior service cost (credit)	3,000,000	3,000,000	3,000,000
Amortization of actuarial loss (gain)	(3,000,000)	0	(1,000,000)
Settlement charges	0	0	0
Special termination benefits	3,000,000	0	14,000,000
Net periodic benefit cost	2,000,000	5,000,000	16,000,000
Regulatory adjustment	0	0	(14,000,000)
Total expense recognized	2,000,000	5,000,000	2,000,000
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax [Abstract]
Net loss (gain)	0	0	0
Prior service cost	0	0	0
Amortization of actuarial loss	0	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax	0	0	0
Total recognized in OCI	0	0	0
Total recognized in net periodic benefit cost and OCI	$ 2,000,000	$ 5,000,000	$ 2,000,000
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.30%	3.65%
Interest crediting rate	3.36%	2.80%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.65%	4.15%	4.50%
Expected return on plan assets	6.94%	6.91%	6.90%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Interest Crediting Rate	2.80%	2.86%	3.03%
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
Expected employer contributions	$ 0
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2019	10,000,000
2020	10,000,000
2021	10,000,000
2022	11,000,000
2023	11,000,000
2024-2028	$ 51,000,000
San Diego Gas and Electric Company [Member] | Other Postretirement Benefits Plan [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	10.00%	10.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	10.00%	10.00%	10.00%
San Diego Gas and Electric Company [Member] | Other Postretirement Benefits Plan [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Rate of compensation increase	2.00%	2.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Rate of compensation increase	2.00%	2.00%	2.00%
Unfunded Plan [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	$ 226,000,000	$ 234,000,000
Accumulated benefit obligation	201,000,000	215,000,000
Unfunded Plan [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	26,000,000	9,000,000
Unfunded Plan [Member] | Southern California Gas Company [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	25,000,000	24,000,000
Accumulated benefit obligation	21,000,000	21,000,000
Unfunded Plan [Member] | San Diego Gas and Electric Company [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	26,000,000	32,000,000
Accumulated benefit obligation	19,000,000	30,000,000
Funded Plan [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	30,000,000	32,000,000
Fair value of plan assets	$ 20,000,000	$ 21,000,000