Accounts and Notes Receivable and Allowance for Credit Losses - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Apr. 22, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accounts Receivable, Additional Narrative Disclosure	no material changes	no material changes
Gross lease receivables	$ 158			$ 233
Subsequent Event
Financing Receivable, Recorded Investment, Past Due [Line Items]
Sales of leases to third parties without recourse			$ 6