Segments and Related Information (Schedule of Financial Information by Reportable Segment - EBITDA) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
EBITDA:
EBITDA	$ 198.9	$ 95.3	$ 322.4	$ 141.5
Reportable Segments [Member] | Communications [Member]
EBITDA:
EBITDA	59.5	66.4	107.8	128.1
Reportable Segments [Member] | Oil and Gas [Member]
EBITDA:
EBITDA	154.0	53.6	247.9	69.8
Reportable Segments [Member] | Electrical Transmission [Member]
EBITDA:
EBITDA	3.5	(9.9)	6.7	(33.7)
Reportable Segments [Member] | Power Generation and Industrial [Member]
EBITDA:
EBITDA	4.7	4.8	5.6	7.7
Reportable Segments [Member] | Other [Member]
EBITDA:
EBITDA	6.8	0.3	1.5	0.5
Corporate [Member]
EBITDA:
EBITDA	$ (29.6)	$ (19.9)	$ (47.1)	$ (30.9)