Revenue from Contracts with Customers - Contract Liabilities (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2018
Change in Contract with Customer, Liability [Roll Forward]
Balance at December 31, 2017	$ 37
Increase due to cumulative effect of adopting Topic 606	98
Increase due to cash received, excluding revenues recognized in the period	40
Decrease due to revenue recognized	(12)
Balance at March 31, 2018	163
Contract liabilities at March 31, 2018
Other current liabilities		$ 39
Other long-term liabilities - other		124
Total contract liabilities from contracts with customers	$ 37	$ 163