Revenue from Contract with Customers (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Revenue from Contract with Customer [Abstract]
Deferred Revenue, Revenue Recognized	$ 79.3
Average Delivery Point of Barrels in Pipeline System	50.00%

Amount of revenue recognized that was previously reported as deferred or unearned revenue.

No definition available.

Name:	us-gaap_DeferredRevenueRevenueRecognized1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration