Accounts Receivable - Additional Information (Detail) - DPA [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 58		$ 54
Allowance for doubtful accounts, deferred payment arrangement	31		$ 30
Provision for doubtful accounts, accounts receivable	$ 1	$ (1)