Operations and Significant Accounting Policies - New Accounting Pronouncements (Details) $ in Millions	9 Months Ended
Sep. 30, 2017 USD ($)
Improvements to Employee Share-Based Payment Accounting [Member] \| Income Tax Expense (Benefit) [Member] \| Maximum [Member]
New Accounting Pronouncements [Line Items]
Impact of Adoption Annually	$ 1

Represents the quantification of the effect of adopting the new accounting standard or change in accounting principle expected by the entity to have a significant effect on the entity's financial statements.

No definition available.

Name:	us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfAdoptionQuantification
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration