FAIR VALUE OF FINANCIAL INSTRUMENTS Estimated Fair Values and Carrying Values of Long-Term Debt (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
FAIR VALUE OF FINANCIAL INSTRUMENTS
Long-term debt (including current maturities) and line of credit, carrying value	$ 6,401	$ 6,344
Long-term debt (including current maturities) and line of credit, fair value (Level 2)	7,245	6,995
Fixed interest rate
FAIR VALUE OF FINANCIAL INSTRUMENTS
Long-term debt (including current maturities) and line of credit, carrying value	5,931	5,694
Long-term debt (including current maturities) and line of credit, fair value (Level 2)	6,775	6,345
Variable interest rate
FAIR VALUE OF FINANCIAL INSTRUMENTS
Long-term debt (including current maturities) and line of credit, carrying value	470	650
Long-term debt (including current maturities) and line of credit, fair value (Level 2)	$ 470	$ 650