Derivatives and Other Financial Instruments - Schedule of Carrying Values and Fair Values of Other Financial Instruments (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Carrying Value [Member]
Derivative [Line Items]
Cash and cash equivalents	$ 1,119	$ 853
Restricted cash	8	6
Long-term debt due within one year	17	21
Long-term debt, less amount due within one year	1,384	1,424
Fair Value [Member]
Derivative [Line Items]
Cash and cash equivalents	1,119	853
Restricted cash	8	6
Long-term debt due within one year	17	21
Long-term debt, less amount due within one year	$ 1,565	$ 1,573