Revenue from Contracts with Customers - Contract Liabilities (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2019
Change in Contract with Customer, Liability [Roll Forward]
Balance at December 31, 2018	$ 150
Increase due to cash received, excluding revenues recognized in the period	21
Decrease due to revenue recognized	(18)
Balance at March 31, 2019	153
Contract liabilities at March 31, 2019
Other current liabilities		$ 23
Other long-term liabilities - other		130
Total contract liabilities from contracts with customers	$ 150	$ 153