Basis of Presentation and Summary of Significant Accounting Policies (Goodwill, by Reporting Unit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2020
Goodwill [Line Items]
Goodwill	$ 138.6	$ 138.6		$ 218.9
Goodwill Impairments during the Period	0.0	(80.3)	$ 0.0
Arrow
Goodwill [Line Items]
Goodwill	45.9			45.9
Goodwill Impairments during the Period		0.0
Powder River Basin
Goodwill [Line Items]
Goodwill	0.0			80.3
Goodwill Impairments during the Period		(80.3)
NGL Marketing and Logistics
Goodwill [Line Items]
Goodwill	92.7			$ 92.7
Goodwill Impairments during the Period		0.0
CMLP
Goodwill [Line Items]
Goodwill	138.6	138.6
Goodwill Impairments during the Period	$ 0.0	$ (80.3)	$ 0.0