Segments and Related Information (Schedule of Financial Information by Reportable Segment - EBITDA) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
EBITDA:
EBITDA	$ 123.5	$ 46.2
Reportable Segments [Member] | Communications [Member]
EBITDA:
EBITDA	48.4	61.7
Reportable Segments [Member] | Oil and Gas [Member]
EBITDA:
EBITDA	93.9	16.2
Reportable Segments [Member] | Electrical Transmission [Member]
EBITDA:
EBITDA	3.2	(23.8)
Reportable Segments [Member] | Power Generation and Industrial [Member]
EBITDA:
EBITDA	0.8	2.9
Reportable Segments [Member] | Other [Member]
EBITDA:
EBITDA	(5.3)	0.2
Corporate [Member]
EBITDA:
EBITDA	$ (17.5)	$ (11.0)