EMPLOYEE BENEFIT PLANS - EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Liability, Defined Benefit Plan [Abstract]
Noncurrent liabilities	$ (1,059)	$ (1,067)
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Expected return on plan assets	6.75%
Pension Plan [Member]
CHANGE IN PROJECTED BENEFIT OBLIGATION
Net obligation at January 1	$ 3,768	3,339
Service cost	129	110	$ 124
Interest cost	129	139	140
Contributions from plan participants	0	0
Actuarial loss	351	445
Plan amendments	0	5
Benefit payments	(93)	(93)
Settlements	(207)	(177)
Net obligation at December 31	4,077	3,768	3,339
CHANGE IN PLAN ASSETS
Fair value of plan assets at January 1	2,662	2,160
Actual return on plan assets	350	496
Employer contributions	290	276
Contributions from plan participants	0	0
Benefit payments	(93)	(93)
Settlements	(207)	(177)
Net recorded (liability) asset at December 31	3,002	2,662	2,160
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status at December 31	(1,075)	(1,106)
Net recorded (liability) asset at December 31	(1,075)	(1,106)
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	0	0
Current liabilities	(35)	(59)
Noncurrent liabilities	(1,040)	(1,047)
Net recorded (liability) asset	(1,075)	(1,106)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]
Net actuarial (loss) gain	(102)	(113)
Prior service cost	(11)	(14)
Total	(113)	(127)
NET PERIODIC BENEFIT COST AND AMOUNTS RECOGNIZED IN OCI
Service cost	129	110	124
Interest cost	129	139	140
Expected return on assets	(169)	(144)	(157)
Amortization of prior service cost (credit)	12	12	11
Amortization of actuarial loss (gain)	35	36	22
Settlement charges	22	28	66
Special termination benefits	0	0	0
Net periodic benefit cost	158	181	206
Regulatory adjustment	91	77	(30)
Total expense recognized	249	258	176
CHANGES IN PLAN ASSETS AND BENEFIT OBLIGATIONS RECOGNIZED IN OCI (1)
Net loss (gain)	28	17	56
Prior service cost	0	5	12
Amortization of actuarial loss	(14)	(13)	(12)
Amortization of prior service cost	(4)	(3)	(2)
Settlements	(22)	(28)	(12)
Total recognized in OCI	(12)	(22)	42
Total recognized in net periodic benefit cost and OCI	$ 237	$ 236	$ 218
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Discount rate	2.78%	3.49%
Interest crediting rate	1.62%	2.28%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Discount rate	3.49%	4.29%	3.64%
Expected return on plan assets	7.00%	7.00%	7.00%
Interest crediting rate	2.28%	3.36%	2.80%
EXPECTED CONTRIBUTIONS
Expected employer contributions	$ 246
EXPECTED BENEFIT PAYMENTS
2021	389
2022	268
2023	255
2024	246
2025	239
2026-2030	$ 1,130
Pension Plan [Member] | Minimum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	2.70%	2.70%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	2.70%	2.00%	2.00%
Pension Plan [Member] | Maximum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	10.00%	10.00%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	10.00%	10.00%	10.00%
Other Postretirement Benefits Plan [Member]
CHANGE IN PROJECTED BENEFIT OBLIGATION
Net obligation at January 1	$ 913	$ 868
Service cost	18	17	$ 21
Interest cost	33	36	36
Contributions from plan participants	22	21
Actuarial loss	79	45
Plan amendments	0	0
Benefit payments	(74)	(72)
Settlements	(2)	(2)
Net obligation at December 31	989	913	868
CHANGE IN PLAN ASSETS
Fair value of plan assets at January 1	1,281	1,108
Actual return on plan assets	164	218
Employer contributions	8	8
Contributions from plan participants	22	21
Benefit payments	(74)	(72)
Settlements	(2)	(2)
Net recorded (liability) asset at December 31	1,399	1,281	1,108
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status at December 31	410	368
Net recorded (liability) asset at December 31	410	368
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	430	391
Current liabilities	(1)	(3)
Noncurrent liabilities	(19)	(20)
Net recorded (liability) asset	410	368
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]
Net actuarial (loss) gain	8	10
Prior service cost	0	0
Total	8	10
NET PERIODIC BENEFIT COST AND AMOUNTS RECOGNIZED IN OCI
Service cost	18	17	21
Interest cost	33	36	36
Expected return on assets	(55)	(71)	(70)
Amortization of prior service cost (credit)	(2)	0	1
Amortization of actuarial loss (gain)	(10)	(10)	(6)
Settlement charges	0	0	0
Special termination benefits	0	0	5
Net periodic benefit cost	(16)	(28)	(13)
Regulatory adjustment	16	29	17
Total expense recognized	0	1	4
CHANGES IN PLAN ASSETS AND BENEFIT OBLIGATIONS RECOGNIZED IN OCI (1)
Net loss (gain)	1	(3)	(4)
Prior service cost	0	0	0
Amortization of actuarial loss	0	0	0
Amortization of prior service cost	0	0	0
Settlements	0	0	0
Total recognized in OCI	1	(3)	(4)
Total recognized in net periodic benefit cost and OCI	$ 1	$ (2)	$ 0
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Discount rate	2.88%	3.54%
Interest crediting rate	1.62%	2.28%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Discount rate	3.54%	4.29%	3.68%
Expected return on plan assets	4.64%	6.48%	6.49%
Interest crediting rate	2.28%	3.36%	2.80%
EXPECTED CONTRIBUTIONS
Expected employer contributions	$ 5
EXPECTED BENEFIT PAYMENTS
2021	47
2022	47
2023	48
2024	48
2025	47
2026-2030	$ 235
Other Postretirement Benefits Plan [Member] | Pre-65Retiree [Member]
ASSUMED HEALTH CARE COST TREND RATES
Health care cost trend rate assumed for next year	6.00%	6.25%	6.50%
Rate to which the cost trend rate is assumed to decline (the ultimate trend)	4.75%	4.75%	4.75%
Other Postretirement Benefits Plan [Member] | Retiree Aged 65 or Older [Member]
ASSUMED HEALTH CARE COST TREND RATES
Health care cost trend rate assumed for next year	4.75%	4.75%	4.75%
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] | Minimum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	2.70%	2.70%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	2.70%	2.00%	2.00%
Other Postretirement Benefits Plan [Member] | Maximum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	10.00%	10.00%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	10.00%	10.00%	10.00%
San Diego Gas and Electric Company [Member]
Liability, Defined Benefit Plan [Abstract]
Noncurrent liabilities	$ (92)	$ (153)
San Diego Gas and Electric Company [Member] | Pension Plan [Member]
CHANGE IN PROJECTED BENEFIT OBLIGATION
Net obligation at January 1	895	814
Service cost	31	30	$ 30
Interest cost	30	34	35
Contributions from plan participants	0	0
Actuarial loss	37	61
Plan amendments	0	3
Benefit payments	(18)	(18)
Settlements	(52)	(39)
Transfer of liability from other plans	(10)	10
Net obligation at December 31	913	895	814
CHANGE IN PLAN ASSETS
Fair value of plan assets at January 1	739	600
Actual return on plan assets	94	135
Employer contributions	52	52
Contributions from plan participants	0	0
Benefit payments	(18)	(18)
Settlements	(52)	(39)
Transfer of assets from other plans	4	9
Net recorded (liability) asset at December 31	819	739	600
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status at December 31	(94)	(156)
Net recorded (liability) asset at December 31	(94)	(156)
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	0	0
Current liabilities	(2)	(3)
Noncurrent liabilities	(92)	(153)
Net recorded (liability) asset	(94)	(156)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]
Net actuarial (loss) gain	(8)	(9)
Prior service cost	(2)	(7)
Total	(10)	(16)
NET PERIODIC BENEFIT COST AND AMOUNTS RECOGNIZED IN OCI
Service cost	31	30	30
Interest cost	30	34	35
Expected return on assets	(49)	(38)	(47)
Amortization of prior service cost (credit)	2	3	2
Amortization of actuarial loss (gain)	3	11	1
Settlement charges	0	0	26
Special termination benefits	0	0	0
Net periodic benefit cost	17	40	47
Regulatory adjustment	38	14	(8)
Total expense recognized	55	54	39
CHANGES IN PLAN ASSETS AND BENEFIT OBLIGATIONS RECOGNIZED IN OCI (1)
Net loss (gain)	6	5	(1)
Prior service cost	0	2	8
Transfer of actuarial loss	(7)	0	0
Transfer of prior service cost	(5)	0	0
Amortization of actuarial loss	(1)	0	(1)
Amortization of prior service cost	(1)	(1)	0
Settlements	0	0	(4)
Total recognized in OCI	(8)	6	2
Total recognized in net periodic benefit cost and OCI	$ 47	$ 60	$ 41
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Discount rate	2.73%	3.44%
Interest crediting rate	1.62%	2.28%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Discount rate	3.44%	4.29%	3.64%
Expected return on plan assets	7.00%	7.00%	7.00%
Interest crediting rate	2.28%	3.36%	2.80%
EXPECTED CONTRIBUTIONS
Expected employer contributions	$ 53
EXPECTED BENEFIT PAYMENTS
2021	112
2022	68
2023	65
2024	61
2025	60
2026-2030	$ 263
San Diego Gas and Electric Company [Member] | Pension Plan [Member] | Minimum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	2.70%	2.70%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	2.70%	2.00%	2.00%
San Diego Gas and Electric Company [Member] | Pension Plan [Member] | Maximum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	10.00%	10.00%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	10.00%	10.00%	10.00%
San Diego Gas and Electric Company [Member] | Other Postretirement Benefits Plan [Member]
CHANGE IN PROJECTED BENEFIT OBLIGATION
Net obligation at January 1	$ 177	$ 170
Service cost	4	4	$ 5
Interest cost	6	7	7
Contributions from plan participants	8	7
Actuarial loss	17	7
Plan amendments	0	0
Benefit payments	(20)	(18)
Settlements	0	0
Transfer of liability from other plans	1	0
Net obligation at December 31	193	177	170
CHANGE IN PLAN ASSETS
Fair value of plan assets at January 1	197	172
Actual return on plan assets	26	36
Employer contributions	1	0
Contributions from plan participants	8	7
Benefit payments	(20)	(18)
Settlements	0	0
Transfer of assets from other plans	1	0
Net recorded (liability) asset at December 31	213	197	172
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status at December 31	20	20
Net recorded (liability) asset at December 31	20	20
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	20	20
Current liabilities	0	0
Noncurrent liabilities	0	0
Net recorded (liability) asset	20	20
NET PERIODIC BENEFIT COST AND AMOUNTS RECOGNIZED IN OCI
Service cost	4	4	5
Interest cost	6	7	7
Expected return on assets	(10)	(11)	(13)
Amortization of prior service cost (credit)	0	2	3
Amortization of actuarial loss (gain)	(3)	(2)	(3)
Settlement charges	0	0	0
Special termination benefits	0	0	3
Net periodic benefit cost	(3)	0	2
Regulatory adjustment	3	0	0
Total expense recognized	0	0	2
CHANGES IN PLAN ASSETS AND BENEFIT OBLIGATIONS RECOGNIZED IN OCI (1)
Net loss (gain)	0	0	0
Prior service cost	0	0	0
Transfer of actuarial loss	0	0	0
Transfer of prior service cost	0	0	0
Amortization of actuarial loss	0	0	0
Amortization of prior service cost	0	0	0
Settlements	0	0	0
Total recognized in OCI	0	0	0
Total recognized in net periodic benefit cost and OCI	$ 0	$ 0	$ 2
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Discount rate	2.85%	3.55%
Interest crediting rate	1.62%	2.28%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Discount rate	3.55%	4.30%	3.65%
Expected return on plan assets	5.51%	6.92%	6.94%
Interest crediting rate	2.28%	3.36%	2.80%
EXPECTED CONTRIBUTIONS
Expected employer contributions	$ 1
EXPECTED BENEFIT PAYMENTS
2021	10
2022	10
2023	10
2024	10
2025	10
2026-2030	$ 47
San Diego Gas and Electric Company [Member] | Other Postretirement Benefits Plan [Member] | Minimum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	2.70%	2.70%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	2.70%	2.00%	2.00%
San Diego Gas and Electric Company [Member] | Other Postretirement Benefits Plan [Member] | Maximum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	10.00%	10.00%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	10.00%	10.00%	10.00%
Southern California Gas Company [Member] | Pension Plan [Member]
CHANGE IN PROJECTED BENEFIT OBLIGATION
Net obligation at January 1	$ 2,526	$ 2,148
Service cost	86	68	$ 81
Interest cost	88	91	92
Contributions from plan participants	0	0
Actuarial loss	282	345
Plan amendments	0	2
Benefit payments	(60)	(59)
Settlements	(105)	(65)
Transfer of liability from other plans	12	(4)
Net obligation at December 31	2,829	2,526	2,148
CHANGE IN PLAN ASSETS
Fair value of plan assets at January 1	1,737	1,385
Actual return on plan assets	243	320
Employer contributions	152	152
Contributions from plan participants	0	0
Benefit payments	(60)	(59)
Settlements	(105)	(65)
Transfer of assets from other plans	2	4
Net recorded (liability) asset at December 31	1,969	1,737	1,385
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status at December 31	(860)	(789)
Net recorded (liability) asset at December 31	(860)	(789)
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	0	0
Current liabilities	(7)	(4)
Noncurrent liabilities	(853)	(785)
Net recorded (liability) asset	(860)	(789)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]
Net actuarial (loss) gain	(14)	(7)
Prior service cost	(4)	(3)
Total	(18)	(10)
NET PERIODIC BENEFIT COST AND AMOUNTS RECOGNIZED IN OCI
Service cost	86	68	81
Interest cost	88	91	92
Expected return on assets	(107)	(94)	(98)
Amortization of prior service cost (credit)	8	8	8
Amortization of actuarial loss (gain)	26	16	13
Settlement charges	0	0	32
Special termination benefits	0	0	0
Net periodic benefit cost	101	89	128
Regulatory adjustment	53	63	(22)
Total expense recognized	154	152	106
CHANGES IN PLAN ASSETS AND BENEFIT OBLIGATIONS RECOGNIZED IN OCI (1)
Net loss (gain)	6	2	1
Prior service cost	0	3	0
Transfer of actuarial loss	5	(4)	0
Transfer of prior service cost	3	(1)	0
Amortization of actuarial loss	(1)	(1)	0
Amortization of prior service cost	(1)	0	(1)
Total recognized in OCI	12	(1)	0
Total recognized in net periodic benefit cost and OCI	$ 166	$ 151	$ 106
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Discount rate	2.79%	3.50%
Interest crediting rate	1.62%	2.28%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Discount rate	3.50%	4.30%	3.65%
Expected return on plan assets	7.00%	7.00%	7.00%
Interest crediting rate	2.28%	3.36%	2.80%
EXPECTED CONTRIBUTIONS
Expected employer contributions	$ 157
EXPECTED BENEFIT PAYMENTS
2021	226
2022	172
2023	166
2024	159
2025	157
2026-2030	$ 752
Southern California Gas Company [Member] | Pension Plan [Member] | Minimum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	2.70%	2.70%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	2.70%	2.00%	2.00%
Southern California Gas Company [Member] | Pension Plan [Member] | Maximum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	10.00%	10.00%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	10.00%	10.00%	10.00%
Southern California Gas Company [Member] | Other Postretirement Benefits Plan [Member]
CHANGE IN PROJECTED BENEFIT OBLIGATION
Net obligation at January 1	$ 688	$ 646
Service cost	14	12	$ 15
Interest cost	25	27	27
Contributions from plan participants	14	13
Actuarial loss	57	39
Plan amendments	0	0
Benefit payments	(49)	(49)
Settlements	0	0
Transfer of liability from other plans	0	0
Net obligation at December 31	749	688	646
CHANGE IN PLAN ASSETS
Fair value of plan assets at January 1	1,059	916
Actual return on plan assets	134	178
Employer contributions	1	1
Contributions from plan participants	14	13
Benefit payments	(49)	(49)
Settlements	0	0
Transfer of assets from other plans	0	0
Net recorded (liability) asset at December 31	1,159	1,059	916
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status at December 31	410	371
Net recorded (liability) asset at December 31	410	371
Liability, Defined Benefit Plan [Abstract]
Noncurrent assets	410	371
Current liabilities	0	0
Noncurrent liabilities	0	0
Net recorded (liability) asset	410	371
NET PERIODIC BENEFIT COST AND AMOUNTS RECOGNIZED IN OCI
Service cost	14	12	15
Interest cost	25	27	27
Expected return on assets	(43)	(58)	(56)
Amortization of prior service cost (credit)	(2)	(2)	(3)
Amortization of actuarial loss (gain)	(7)	(8)	(2)
Settlement charges	0	0	0
Special termination benefits	0	0	2
Net periodic benefit cost	(13)	(29)	(17)
Regulatory adjustment	13	29	17
Total expense recognized	0	0	0
CHANGES IN PLAN ASSETS AND BENEFIT OBLIGATIONS RECOGNIZED IN OCI (1)
Net loss (gain)	0	0	0
Prior service cost	0	0	0
Transfer of actuarial loss	0	0	0
Transfer of prior service cost	0	0	0
Amortization of actuarial loss	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	$ 0	$ 0
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Discount rate	2.90%	3.55%
Interest crediting rate	1.62%	2.28%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Discount rate	3.55%	4.30%	3.70%
Expected return on plan assets	4.41%	6.38%	6.38%
Interest crediting rate	2.28%	3.36%	2.80%
EXPECTED CONTRIBUTIONS
Expected employer contributions	$ 1
EXPECTED BENEFIT PAYMENTS
2021	34
2022	34
2023	35
2024	35
2025	35
2026-2030	$ 172
Southern California Gas Company [Member] | Other Postretirement Benefits Plan [Member] | Minimum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	2.70%	2.70%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	2.70%	2.00%	2.00%
Southern California Gas Company [Member] | Other Postretirement Benefits Plan [Member] | Maximum [Member]
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE BENEFIT OBLIGATION
Rate of compensation increase	10.00%	10.00%
WEIGHTED-AVERAGE ASSUMPTIONS USED TO DETERMINE NET PERIODIC BENEFIT COST
Rate of compensation increase	10.00%	10.00%	10.00%
Funded Plan [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	$ 3,679	$ 3,578
Accumulated benefit obligation	3,265	3,229
Fair value of plan assets	2,788	2,662
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	33	32
Fair value of plan assets	27	25
Funded 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	887	861
Accumulated benefit obligation	834	818
Fair value of plan assets	819	739
Funded 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	2,792	2,505
Accumulated benefit obligation	2,431	2,208
Fair value of plan assets	1,969	1,737
Unfunded Plan [Member] | Pension Plan [Member]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	184	190
Accumulated benefit obligation	146	158
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	14	16
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	34
Accumulated benefit obligation	22	27
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	37	21
Accumulated benefit obligation	$ 31	$ 17