Inventories, Net - Summary of Inventories (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Finished goods and other				$ 630	$ 531	$ 737
Less: inventory reserves	$ (40)	$ (48)	$ (44)	(40)	(48)	(44)
Total				$ 590	$ 483	$ 693
Inventory reserves:
Inventory reserves, Beginning balance	48	44	39
Additions charged to expenses	11	36	54
Inventory reserves, Charge-offs and other	(19)	(32)	(49)
Inventory reserves, Ending balance	$ 40	$ 48	$ 44