SUPPLEMENTAL FINANCIAL INFORMATION - Net Interest Expense (Detail) - USD ($) $ in Millions	3 Months Ended					6 Months Ended		12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest Income Expense Net
Interest costs								$ 120	$ 105	$ 98
Interest costs capitalized								(9)	(12)	(13)
Interest expense								111	93	85
Interest income								(40)	(48)	(30)
Interest expense, net	$ 20	$ 18	$ 11	$ 11	$ 12	$ 38	$ 23	$ 71	$ 45	$ 55