Legal Proceedings (Narrative) (Details) $ in Millions	Mar. 31, 2018 USD ($)
Legal Reserve [Member] \| Maximum [Member]
Loss Contingencies [Line Items]
Loss contingency, range of possible loss not accrued	$ 100

The difference between the maximum amount of estimated loss and the amount recorded as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 05
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6395354&loc=d3e12631-108344

Name:	us-gaap_LossContingencyRangeOfPossibleLossPortionNotAccrued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant