ESTIMATES, SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND BALANCE SHEET DETAIL Estimates, Significant Accounting Policies and Balance Sheet Detail - PPE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 3,281	$ 3,196
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	607	507
Net property, plant and equipment	2,674	2,689
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	4	3
Construction Work-In-Process [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	40	37
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 194	158
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P6Y0M
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P46Y0M
Pipelines [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 2,556	2,556
Pipelines [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P5Y0M
Pipelines [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P46Y0M
Natural Gas, Storage [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 348	282
Natural Gas, Storage [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P26Y0M
Natural Gas, Storage [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P46Y0M
Property, Plant and Equipment, Other Types [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 139	$ 160
Property, Plant and Equipment, Other Types [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P3Y0M
Property, Plant and Equipment, Other Types [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P21Y0M