GENERAL INFORMATION AND OTHER FINANCIAL DATA - DUE TO DUE FROM AFFILIATES (Details) $ in Billions	3 Months Ended	12 Months Ended
	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)		Mar. 31, 2019 MXN ($)
Related Party Transaction [Line Items]
Due from unconsolidated affiliates - current	$ 50,000,000	$ 37,000,000	[1]
Due from unconsolidated affiliates - noncurrent	668,000,000	644,000,000	[1]
Due to unconsolidated affiliates, current	(10,000,000)	(10,000,000)	[1]
Due to unconsolidated affiliates - noncurrent	$ (38,000,000)	$ (37,000,000)	[1]
ESJ joint venture [Member] | LIBOR [Member]
Related Party Transaction [Line Items]
Spread on variable rate	6.375%	6.375%
Interest rate on due from affiliate, noncurrent		8.89%
TAG Pipeline Norte [Member]
Related Party Transaction [Line Items]
Interest rate on due from affiliate, noncurrent	5.54%
TAG Pipeline Norte [Member] | LIBOR [Member]
Related Party Transaction [Line Items]
Spread on variable rate	2.90%	2.90%
California Utilities Combined [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity	$ 1,000,000,000
San Diego Gas and Electric Company [Member]
Related Party Transaction [Line Items]
Due to unconsolidated affiliates, current	(63,000,000)	$ (61,000,000)	[1]
Maximum borrowing capacity	750,000,000
San Diego Gas and Electric Company [Member] | Due to/from Sempra Energy [Member]
Related Party Transaction [Line Items]
Due to unconsolidated affiliates, current	(37,000,000)	(43,000,000)
Income taxes due (to) from Sempra Energy	(29,000,000)	5,000,000
San Diego Gas and Electric Company [Member] | Due to/from SoCalGas [Member]
Related Party Transaction [Line Items]
Due to unconsolidated affiliates, current	(14,000,000)	(6,000,000)
San Diego Gas and Electric Company [Member] | Due to/from Other affiliates [Member]
Related Party Transaction [Line Items]
Due to unconsolidated affiliates, current	(12,000,000)	(12,000,000)
Southern California Gas Company [Member]
Related Party Transaction [Line Items]
Due from unconsolidated affiliates - current	15,000,000	7,000,000	[1]
Due to unconsolidated affiliates, current	(42,000,000)	(34,000,000)	[1]
Maximum borrowing capacity	750,000,000
Southern California Gas Company [Member] | Due to/from Sempra Energy [Member]
Related Party Transaction [Line Items]
Due to unconsolidated affiliates, current	(39,000,000)	(34,000,000)
Income taxes due (to) from Sempra Energy	(88,000,000)	(4,000,000)
Southern California Gas Company [Member] | Due to/from Other affiliates [Member]
Related Party Transaction [Line Items]
Due from unconsolidated affiliates - current	1,000,000	1,000,000
Due to unconsolidated affiliates, current	(3,000,000)	0
Southern California Gas Company [Member] | Due to/from SDG&E
Related Party Transaction [Line Items]
Due from unconsolidated affiliates - current	14,000,000	6,000,000
Sempra Mexico [Member] | IMG [Member]
Related Party Transaction [Line Items]
Due from unconsolidated affiliates - noncurrent	668,000,000	$ 641,000,000
Maximum borrowing capacity	$ 729,000,000			$ 14.2
Sempra Mexico [Member] | IMG [Member] | Interbank Equilibrium Rate [Member]
Related Party Transaction [Line Items]
Spread on variable rate	2.20%	2.20%
Interest rate on due from affiliate, noncurrent	10.69%
Sempra Mexico [Member] | ESJ joint venture [Member]
Related Party Transaction [Line Items]
Due from unconsolidated affiliates - noncurrent	$ 0	$ 3,000,000
Sempra Mexico [Member] | TAG Pipeline Norte [Member]
Related Party Transaction [Line Items]
Due to unconsolidated affiliates - noncurrent	$ 38,000,000	$ 37,000,000

[1] Derived from audited financial statements.