NEW ACCOUNTING STANDARDS - BALANCE SHEET IMPACT (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets	$ 324		$ 249
Property, plant and equipment, net	36,452		34,439
Right-of-use assets – operating leases	591
Deferred income taxes	2,577		2,321
Other current liabilities	866		935
Deferred credits and other	2,048		1,493
Retained earnings	11,130		10,104
Other noncontrolling interests	1,856		2,090
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Assets held for sale		$ 13
Other long-term assets		(71)
Property, plant and equipment, net		(147)
Right-of-use assets – operating leases		603
Deferred income taxes		(3)
Other current liabilities		80
Long-term debt and finance leases		(138)
Deferred credits and other		436
Retained earnings		17
Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred income taxes	4
Other current liabilities	4
Deferred credits and other	2
Retained earnings	(7)
Other noncontrolling interests	(2)
Accounts receivable – trade, net	(1)
Due from unconsolidated affiliates – noncurrent	(6)
San Diego Gas and Electric Company [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets	24		5
Property, plant and equipment, net	16,967		16,310
Right-of-use assets – operating leases	130
Deferred income taxes	1,848		1,616
Other current liabilities	176		141
Deferred credits and other	677		488
Retained earnings	5,456		4,687
Other noncontrolling interests	0		100
San Diego Gas and Electric Company [Member] | Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Assets held for sale		0
Other long-term assets		0
Property, plant and equipment, net		0
Right-of-use assets – operating leases		130
Deferred income taxes		0
Other current liabilities		20
Long-term debt and finance leases		0
Deferred credits and other		110
Retained earnings		0
Southern California Gas Company [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets	44		29
Property, plant and equipment, net	13,324		12,439
Right-of-use assets – operating leases	94
Deferred income taxes	1,403		1,177
Other current liabilities	222		217
Deferred credits and other	422		330
Retained earnings	$ 3,883		$ 3,390
Southern California Gas Company [Member] | Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Assets held for sale		0
Other long-term assets		0
Property, plant and equipment, net		0
Right-of-use assets – operating leases		116
Deferred income taxes		0
Other current liabilities		23
Long-term debt and finance leases		0
Deferred credits and other		93
Retained earnings		$ 0