Accounts Receivable (Narrative) (Details) $ in Millions	Jan. 01, 2018 USD ($)
Adjustments For ASC 606 [Member] \| Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for Doubtful Accounts Receivable, Recoveries	$ 32

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.

Name:	us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration