OTHER CONTINGENCIES AND COMMITMENTS (Nuclear Insurance) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) nuclear_generating_unit
Long-term Purchase Commitment [Line Items]
Number of nuclear generating units (nuclear generating unit) | nuclear_generating_unit	2
Maximum total payment incurred per event under the loss sharing program	$ 450
Humboldt Bay Unit
Long-term Purchase Commitment [Line Items]
Amount of property damage coverage provided by NEIL	131
Amount of liability insurance for Humboldt Bay Unit 3	53
Diablo Canyon
Long-term Purchase Commitment [Line Items]
Maximum public liability per nuclear incident under Price-Anderson Act	14,100
Maximum available public liability insurance for Diablo Canyon as required by Price-Anderson Act	450
Maximum annual payment incurred per event under the loss sharing program	275
Coverage for purchased public liability insurance, per incident	$ 41
Period for inflation adjustment	5 years
Nuclear Incident
Long-term Purchase Commitment [Line Items]
Amount of property damage and business interruption coverage provided by NEIL for Diablo Canyon	$ 3,200
Nuclear Incident | Humboldt Bay Unit
Long-term Purchase Commitment [Line Items]
Amount of indemnification from the NRC for public liability arising from nuclear incidents	500
Non-Nuclear Incident
Long-term Purchase Commitment [Line Items]
Amount of property damage and business interruption coverage provided by NEIL for Diablo Canyon	2,600
Nuclear Electric Insurance Limited
Long-term Purchase Commitment [Line Items]
Potential premium obligation	47
European Mutual Association for Nuclear Insurance
Long-term Purchase Commitment [Line Items]
Full insurance policy limit	200
Potential premium obligation	$ 3