CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 960	$ 108
Restricted cash	22	31
Accounts receivable – trade, net	1,578	1,261
Accounts receivable – other, net	403	455
Due from unconsolidated affiliates	20	32
Income taxes receivable	113	112
Inventories	308	277
Regulatory assets	190	222
Greenhouse gas allowances	553	72
Assets held for sale in discontinued operations	0	445
Other current assets	364	324
Total current assets	4,511	3,339
Other assets:
Restricted cash	3	3
Due from unconsolidated affiliates	780	742
Regulatory assets	1,822	1,930
Nuclear decommissioning trusts	1,019	1,082
Investment in Oncor Holdings	12,440	11,519
Other investments	1,388	2,103
Goodwill	1,602	1,602
Other intangible assets	202	213
Dedicated assets in support of certain benefit plans	512	488
Insurance receivable for Aliso Canyon costs	445	339
Deferred income taxes	136	155
Greenhouse gas allowances	101	470
Right-of-use assets	543	591
Wildfire fund	363	392
Assets held for sale in discontinued operations	0	3,513
Other long-term assets	753	732
Total other assets	22,109	25,874
Property, plant and equipment:
Property, plant and equipment	53,928	49,329
Less accumulated depreciation and amortization	(13,925)	(12,877)
Property, plant and equipment, net	40,003	36,452
Total assets	66,623	65,665
Liabilities, Current [Abstract]
Short-term debt	885	3,505
Accounts payable – trade	1,359	1,234
Accounts payable – other	154	179
Due to unconsolidated affiliates	45	5
Dividends and interest payable	551	515
Accrued compensation and benefits	446	476
Regulatory liabilities	140	319
Current portion of long-term debt and finance leases	1,540	1,526
Reserve for Aliso Canyon costs	150	9
Greenhouse gas obligations	553	72
Liabilities held for sale in discontinued operations	0	444
Other current liabilities	1,016	866
Total current liabilities	6,839	9,150
Long-term debt and finance leases	21,781	20,785
Deferred Credits and Other Liabilities [Abstract]
Due to unconsolidated affiliates	234	195
Pension and other postretirement benefit plan obligations, net of plan assets	1,059	1,067
Deferred Income Tax Liabilities, Net	2,871	2,577
Regulatory liabilities	3,372	3,741
Reserve for Aliso Canyon costs	301	7
Asset retirement obligations	3,113	2,923
Greenhouse gas obligations	0	301
Liabilities held for sale in discontinued operations	0	1,052
Deferred credits and other	2,119	2,062
Total deferred credits and other liabilities	13,069	13,925
Commitments and contingencies (Note 16)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Common stock	7,053	7,480
Retained earnings	13,673	11,130
Accumulated other comprehensive income (loss)	(500)	(939)
Total shareholders’ equity	23,373	19,929
Preferred stock of subsidiary	20	20
Other noncontrolling interests	1,541	1,856
Total equity	24,934	21,805
Total liabilities and shareholders’ equity	$ 66,623	$ 65,665
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares outstanding (in shares)	288,470,244	291,712,925
Common stock, shares authorized (in shares)	750,000,000	750,000,000
San Diego Gas and Electric Company [Member]
Current assets:
Cash and cash equivalents	$ 262	$ 10
Accounts receivable – trade, net	573	398
Accounts receivable – other, net	143	119
Income taxes receivable	0	128
Inventories	104	94
Prepaid expenses	153	120
Regulatory assets	174	209
Fixed-price contracts and other derivatives	56	43
Greenhouse gas allowances	113	13
Other current assets	22	24
Total current assets	1,600	1,158
Other assets:
Regulatory assets	534	440
Nuclear decommissioning trusts	1,019	1,082
Greenhouse gas allowances	83	189
Right-of-use assets	102	130
Wildfire fund	363	392
Other long-term assets	189	202
Total other assets	2,290	2,435
Property, plant and equipment:
Property, plant and equipment	24,436	22,504
Less accumulated depreciation and amortization	(6,015)	(5,537)
Property, plant and equipment, net	18,421	16,967
Total assets	22,311	20,560
Liabilities, Current [Abstract]
Short-term debt	0	80
Accounts payable – trade	553	496
Due to unconsolidated affiliates	64	53
Interest payable	46	43
Accrued compensation and benefits	135	138
Regulatory liabilities	61	76
Accrued franchise fees	56	53
Current portion of long-term debt and finance leases	611	56
Customer deposits	56	74
Asset retirement obligations	117	95
Greenhouse gas obligations	113	13
Other current liabilities	199	133
Total current liabilities	2,011	1,310
Long-term debt and finance leases	6,866	6,306
Deferred Credits and Other Liabilities [Abstract]
Pension and other postretirement benefit plan obligations, net of plan assets	92	153
Deferred Income Tax Liabilities, Net	2,019	1,848
Deferred investment tax credits	13	14
Regulatory liabilities	2,195	2,319
Asset retirement obligations	759	771
Greenhouse gas obligations	0	62
Deferred credits and other	626	677
Total deferred credits and other liabilities	5,704	5,844
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Preferred stock	0	0
Common stock	1,660	1,660
Retained earnings	6,080	5,456
Accumulated other comprehensive income (loss)	(10)	(16)
Total shareholders’ equity	7,730	7,100
Total equity	7,730	7,100
Total liabilities and shareholders’ equity	$ 22,311	$ 20,560
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares authorized (in shares)	45,000,000	45,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, shares outstanding (in shares)	117,000,000	117,000,000
Common stock, shares authorized (in shares)	255,000,000	255,000,000
Southern California Gas Company [Member]
Current assets:
Cash and cash equivalents	$ 4	$ 10
Accounts receivable – trade, net	786	710
Accounts receivable – other, net	64	87
Due from unconsolidated affiliates	22	11
Income taxes receivable	0	161
Inventories	153	136
Regulatory assets	16	7
Greenhouse gas allowances	390	52
Other current assets	47	44
Total current assets	1,482	1,218
Other assets:
Regulatory assets	1,208	1,407
Insurance receivable for Aliso Canyon costs	445	339
Greenhouse gas allowances	9	248
Right-of-use assets	74	94
Other long-term assets	499	447
Total other assets	2,235	2,535
Property, plant and equipment:
Property, plant and equipment	21,180	19,362
Less accumulated depreciation and amortization	(6,437)	(6,038)
Property, plant and equipment, net	14,743	13,324
Total assets	18,460	17,077
Liabilities, Current [Abstract]
Short-term debt	113	630
Accounts payable – trade	600	545
Accounts payable – other	122	110
Due to unconsolidated affiliates	31	47
Accrued compensation and benefits	189	182
Regulatory liabilities	79	243
Current portion of long-term debt and finance leases	10	6
Customer deposits	48	71
Asset retirement obligations	59	65
Reserve for Aliso Canyon costs	150	9
Greenhouse gas obligations	390	52
Other current liabilities	291	222
Total current liabilities	2,082	2,182
Long-term debt and finance leases	4,763	3,788
Deferred Credits and Other Liabilities [Abstract]
Pension obligation, net of plan assets	853	785
Deferred Income Tax Liabilities, Net	1,406	1,403
Deferred investment tax credits	8	7
Regulatory liabilities	1,177	1,422
Reserve for Aliso Canyon costs	301	7
Asset retirement obligations	2,309	2,112
Greenhouse gas obligations	0	208
Deferred credits and other	417	415
Total deferred credits and other liabilities	6,471	6,359
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Preferred stock	22	22
Common stock	866	866
Retained earnings	4,287	3,883
Accumulated other comprehensive income (loss)	(31)	(23)
Total shareholders’ equity	5,144	4,748
Total equity	5,144	4,748
Total liabilities and shareholders’ equity	$ 18,460	$ 17,077
Preferred stock, shares authorized (in shares)	11,000,000	11,000,000
Preferred stock, shares outstanding (in shares)	1,000,000	1,000,000
Common stock, shares outstanding (in shares)	91,000,000	91,000,000
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Convertible Preferred Stock Series A [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Preferred stock	$ 1,693	$ 1,693
Preferred stock, shares outstanding (in shares)	17,250,000	17,250,000
Convertible Preferred Stock Series B [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Preferred stock	$ 565	$ 565
Preferred stock, shares outstanding (in shares)	5,750,000	5,750,000
Series C Preferred Stock [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Preferred stock	$ 889	$ 0
Preferred stock, shares outstanding (in shares)	900,000