Pension Benefits Pension (Details) $ in Millions	9 Months Ended
Sep. 30, 2018 USD ($)
Pension Details [Abstract]
Pension Plans, Gain (Loss) Amortization Threshold	10.00%
Pension Contributions	$ 8.1

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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