Segments and Related Information (Schedule of Financial Information by Reportable Segment - EBITDA) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
EBITDA:
EBITDA	$ 236.5	$ 188.7	$ 373.0	$ 293.2
Reportable Segments [Member] | Communications [Member]
EBITDA:
EBITDA	52.4	73.7	97.8	155.8
Reportable Segments [Member] | Oil and Gas [Member]
EBITDA:
EBITDA	179.3	122.7	286.7	155.7
Reportable Segments [Member] | Electrical Transmission [Member]
EBITDA:
EBITDA	8.7	(2.7)	12.4	1.9
Reportable Segments [Member] | Power Generation and Industrial [Member]
EBITDA:
EBITDA	8.9	9.8	12.1	14.6
Reportable Segments [Member] | Other [Member]
EBITDA:
EBITDA	6.4	6.8	12.7	12.7
Corporate [Member]
EBITDA:
EBITDA	$ (19.2)	$ (21.6)	$ (48.7)	$ (47.5)