SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Pipeline replacement costs	$ 237	$ 237
Cash payments arising from operating leases		1,790
ROU assets	2,435	2,435
Lease liabilities	$ 2,427	$ 2,427
Weighted average remaining lease term	6 years 1 month 6 days	6 years 1 month 6 days
Weighted average discount rate	6.10%	6.10%
Period for probable revenue recovery		24 months
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
ROU assets			$ 2,800
Lease liabilities			$ 2,800
Pacific Gas & Electric Co
Lessee, Lease, Description [Line Items]
Pipeline replacement costs	$ 237	$ 237
ROU assets	$ 2,427	$ 2,427