Segments and Related Information (Schedule of Financial Information by Reportable Segment - EBITDA) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
EBITDA:
EBITDA	$ 159.9	$ 236.5	$ 273.8	$ 373.0
Reportable Segments [Member] | Communications [Member]
EBITDA:
EBITDA	76.4	52.4	127.2	97.8
Reportable Segments [Member] | Oil and Gas [Member]
EBITDA:
EBITDA	80.1	179.3	154.5	286.7
Reportable Segments [Member] | Electrical Transmission [Member]
EBITDA:
EBITDA	(3.2)	8.7	5.1	12.4
Reportable Segments [Member] | Power Generation and Industrial [Member]
EBITDA:
EBITDA	30.1	8.9	35.0	12.1
Reportable Segments [Member] | Other [Member]
EBITDA:
EBITDA	7.5	6.4	14.9	12.7
Corporate [Member]
EBITDA:
EBITDA	$ (31.0)	$ (19.2)	$ (62.9)	$ (48.7)