Accounts Receivable, Net (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net		$ 1,326		$ 1,357
Accounts Receivable Sales Arrangements [Abstract]
Uncollected accounts receivable sold and derecognized		114		161
Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Invoiced		1,033		1,048
Accrued		352		368
Allowance for doubtful accounts		(59)		$ (59)
Accounts receivable sales(1)	[1]	103	$ 511
Deferred proceeds		0	52
Loss on sales of accounts receivable		1	3
Estimated decrease to operating cash flows(2)	[2]	$ (50)	$ (65)

[1] Customers may also enter into structured-payable arrangements that require us to sell our receivables from that customer to a third-party financial institution, which then makes payments to us to settle the customer's receivable. In these instances we ensure the sale of the receivables are bankruptcy remote and the payment made to us is without recourse. The activity associated with these arrangements is not reflected in this disclosure as payments under these arrangements have not been material and these are customer directed arrangements.

[2] Represents the difference between current and prior period receivable sales adjusted for the effects of: (i) the deferred proceeds, (ii) collections prior to the end of the quarter and, (iii) currency.