Segments and Related Information (Schedule of Financial Information by Reportable Segment - EBITDA) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
EBITDA:
EBITDA	$ 247.9	$ 222.8	$ 620.8	$ 516.1
Reportable Segments [Member] | Communications [Member]
EBITDA:
EBITDA	57.1	74.8	154.8	230.6
Reportable Segments [Member] | Oil and Gas [Member]
EBITDA:
EBITDA	212.9	155.8	499.6	311.5
Reportable Segments [Member] | Electrical Transmission [Member]
EBITDA:
EBITDA	7.8	3.1	20.3	5.0
Reportable Segments [Member] | Power Generation and Industrial [Member]
EBITDA:
EBITDA	2.3	9.7	14.4	24.3
Reportable Segments [Member] | Other [Member]
EBITDA:
EBITDA	6.7	7.0	19.4	19.7
Corporate [Member]
EBITDA:
EBITDA	$ (38.9)	$ (27.6)	$ (87.7)	$ (75.0)