Pension Pension (Narrative) (Details)	9 Months Ended
Sep. 30, 2017 USD ($)
Pension (Narrative) [Abstract]
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 5,500,000
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	$ 0

Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period.

No definition available.

Name:	us-gaap_DefinedBenefitPlansEstimatedFutureEmployerContributionsInCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration