Accounts and Notes Receivable and Allowance for Credit Losses - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Aug. 05, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accounts Receivable, Additional Narrative Disclosure		no material changes	no material changes	no material changes	no material changes
Gross lease receivables		$ 164		$ 164		$ 233
Subsequent Event
Financing Receivable, Recorded Investment, Past Due [Line Items]
Sales of leases to third parties without recourse	$ 6