Accounts Receivable, Net (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net		$ 1,290		$ 1,290		$ 1,357
Accounts Receivable Sales Arrangements [Abstract]
Uncollected accounts receivable sold and derecognized		98		98		161
Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Invoiced		1,013		1,013		1,048
Accrued		334		334		368
Allowance for doubtful accounts		(57)		(57)		$ (59)
Accounts receivable sales(1)	[1]	66	$ 520	297	$ 1,598
Deferred proceeds		0	56	0	164
Loss on sales of accounts receivable		1	3	2	9
Estimated decrease to operating cash flows(2)	[2]	$ (34)	$ (77)	$ (61)	$ (83)

[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. In third quarter 2018, the $34 decrease reflected lower sales consistent with the seasonality of our European operations.