FAIR VALUE MEASUREMENTS - NONRECURRING FAIR VALUE MEASURES (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	[1]	Jun. 30, 2017	Jun. 30, 2016	[1],[2]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment losses	$ 71	$ 21		$ 71	$ 22
TdM [Member] | Sempra Mexico [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment losses	71			71
Market Approach Valuation Technique [Member] | TdM [Member] | Sempra Mexico [Member] | Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value	$ 62			$ 62
% of fair value measurement	100.00%			100.00%
Range of inputs	100.00%			100.00%

[1] As adjusted for the adoption of ASU 2016-09 as of January 1, 2016.

[2] As adjusted for the adoption of ASU 2016-09 as of January 1, 2016.