Segments and Related Information (Schedule of Financial Information by Reportable Segment - Depreciation and Amortization) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Depreciation and Amortization:
Depreciation and amortization	$ 90.5	$ 60.5
Reportable Segments [Member] | Communications [Member]
Depreciation and Amortization:
Depreciation and amortization	21.8	19.7
Reportable Segments [Member] | Clean Energy and Infrastructure [Member]
Depreciation and Amortization:
Depreciation and amortization	7.6	4.0
Reportable Segments [Member] | Oil and Gas [Member]
Depreciation and Amortization:
Depreciation and amortization	52.1	28.1
Reportable Segments [Member] | Electrical Transmission [Member]
Depreciation and Amortization:
Depreciation and amortization	6.1	5.9
Reportable Segments [Member] | Other [Member]
Depreciation and Amortization:
Depreciation and amortization	0.0	0.0
Corporate [Member]
Depreciation and Amortization:
Depreciation and amortization	$ 2.9	$ 2.8