QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Selected Quarterly Financial Information [Line Items]
Revenues	$ 3,171	$ 2,644	$ 2,526	$ 3,029	$ 2,943	$ 2,758	$ 2,230	$ 2,898	$ 11,370	$ 10,829	$ 10,102
Expenses and other income	2,743	2,443	2,063	2,632	2,444	2,310	1,944	2,397
Income from continuing operations, net of income tax	432	428	528	867	429	653	357	560
Income from discontinued operations, net of income tax	0	(7)	1,777	80	71	256	78	(42)	1,850	363	188
Operating revenues									10,025	9,448	8,539
Net income/Earnings attributable to common shares	432	421	2,305	947	500	909	435	518	4,105	2,362	1,126
Earnings attributable to noncontrolling interest									(172)	(164)	(76)
Earnings attributable to common shares									$ 3,764	$ 2,055	$ 924
Total reclassifications for the period, net of tax	$ 414	$ 351	$ 2,239	$ 760	$ 447	$ 813	$ 354	$ 441
Earnings from continuing operations - Basic EPS (in dollars per share)	$ 1.43	$ 1.23	$ 1.58	$ 2.35	$ 1.36	$ 2.04	$ 1.03	$ 1.79	$ 6.61	$ 6.22	$ 2.86
Basic earnings per common share attributable to Sempra Energy (in dollars per share)	$ 1.43	$ 1.21	$ 7.64	$ 2.60	$ 1.57	$ 2.93	$ 1.29	$ 1.60
Weighted-average number of shares outstanding, basic (in shares)	289,000	289,500	293,100	292,800	284,600	277,400	275,000	274,700	291,077	277,904	268,072
Earnings from continuing operations - Diluted EPS (in dollars per share)	$ 1.43	$ 1.23	$ 1.58	$ 2.30	$ 1.34	$ 2.00	$ 1.01	$ 1.78	$ 6.58	$ 6.13	$ 2.84
Earnings (losses) from discontinued operations (in dollars per share)	0	(0.02)	6.03	0.23	0.21	0.84	0.25	(0.19)	$ 6.30	$ 1.16	$ 0.58
Diluted earnings per common share attributable to Sempra Energy (in dollars per share)	$ 1.43	$ 1.21	$ 7.61	$ 2.53	$ 1.55	$ 2.84	$ 1.26	$ 1.59
Weighted-average number of shares outstanding, diluted (in shares)	290,200	290,600	294,200	313,900	288,800	295,800	279,600	277,200	292,252	282,033	269,852
Dividends on preferred stock									$ (168)	$ (142)	$ (125)
Earnings (losses) from discontinued operations attributable to common shares	$ 0	$ (0.02)	$ 6.06	$ 0.25	$ 0.21	$ 0.89	$ 0.26	$ (0.19)	$ 6.32	$ 1.18	$ 0.59
San Diego Gas and Electric Company [Member]
Selected Quarterly Financial Information [Line Items]
Operating revenues	$ 1,337	$ 1,472	$ 1,235	$ 1,269	$ 1,259	$ 1,427	$ 1,094	$ 1,145	$ 5,313	$ 4,925	$ 4,568
Operating expenses	1,016	1,157	887	880	894	1,004	831	883	3,940	3,612	3,558
Operating income	321	315	348	389	365	423	263	262	1,373	1,313	1,010
Net income/Earnings attributable to common shares					185	266	146	177	824	774	676
Earnings attributable to noncontrolling interest					0	(3)	(3)	(1)	0	(7)	(7)
Earnings attributable to common shares	191	178	193	262	185	263	143	176	824	767	669
Southern California Gas Company [Member]
Selected Quarterly Financial Information [Line Items]
Operating revenues	1,501	842	1,010	1,395	1,383	975	806	1,361	4,748	4,525	3,962
Operating expenses	1,333	826	773	1,031	1,000	762	747	1,060	3,963	3,569	3,371
Operating income	168	16	237	364	383	213	59	301	785	956	591
Net income/Earnings attributable to common shares	79	(24)	147	303	204	143	31	264	505	642	401
Earnings attributable to common shares	79	(24)	146	303	204	143	30	264	504	641	400
Dividends on preferred stock	$ 0	$ 0	$ (1)	$ 0	$ 0	$ 0	$ (1)	$ 0	$ (1)	$ (1)	$ (1)