Revenue Recognition and Accounts Receivable (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Revenue Recognition And Accounts Receivable [Line Items]
Securitized accounts receivable	$ 320	$ 1,040
Receivables Facility [Member]
Revenue Recognition And Accounts Receivable [Line Items]
Accounts receivable securitization facility maximum borrowing capacity	$ 400

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration