Commercial Commitments (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Guarantor Obligations [Line Items]
Total commercial commitments	$ 10.8	$ 9.3
Standby letters of credit [Member]
Guarantor Obligations [Line Items]
Total commercial commitments	9.3	$ 9.3
RRPF Joint Ventures [Member] \| Derivative [Member]
Guarantor Obligations [Line Items]
Total commercial commitments	$ 1.5

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant