Derivatives and Other Financial Instruments - Schedule of Carrying Values and Fair Values of Other Financial Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Carrying Value [Member]
Derivative [Line Items]
Cash and cash equivalents	$ 1,113	$ 1,358
Restricted cash	3	7
Long-term debt due within one year	1	16
Long-term debt, less amount due within one year	1,801	1,388
Fair Value [Member]
Derivative [Line Items]
Cash and cash equivalents	1,113	1,358
Restricted cash	3	7
Long-term debt due within one year	1	16
Long-term debt, less amount due within one year	$ 1,863	$ 1,555