Accounts Receivable, Net (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net		$ 1,276	$ 1,357
Accounts receivable sold, derecognized and uncollected at balance sheet date		131	161
Accounts receivable sales(1)	[1]	405	1,733	$ 2,267
Deferred proceeds (2)	[2]	0	164	233
Loss on sale of accounts receivable		3	10	$ 16
Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Invoiced		999	1,048
Accrued (1)	[3]	333	368
Allowance for doubtful accounts		$ (56)	$ (59)

[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] For sales arrangements terminated in the fourth quarter 2017, a portion of the sales proceeds was normally held back by the purchaser and payment was deferred until collection of the related sold receivables.

[3] Accrued amounts are normally invoiced to customers in the subsequent quarter.