INCOME TAXES Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Other postretirement benefits	$ 18	$ 3
Debt amortization	11	12
Other	74	65
Total deferred income tax assets	103	80
Deferred Tax Assets, Valuation Allowance	0	(2)
Deferred Tax Assets, Net	103	78
Property, plant and equipment	(497)	(484)
Deferred Tax Liabilities, Investment in Noncontrolled Affiliates	(2)	(5)
Other	(41)	(40)
Deferred Tax Liabilities, Gross	(540)	(529)
Deferred Tax Liabilities, Net	$ (437)	$ (451)