Accounts Receivable, Net (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net		$ 1,234		$ 1,276
Accounts Receivable Sales Arrangements [Abstract]
Uncollected accounts receivable sold and derecognized		124		131
Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Invoiced		965		999
Accrued		323		333
Allowance for doubtful accounts		(54)		$ (56)
Accounts Receivable Sales Arrangements [Abstract]
Accounts receivable sales	[1]	88	$ 103
Loss on sales of accounts receivable		$ 1	$ 1

[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.