Segments and Related Information - Schedule of Financial Information by Reportable Segment- EBITDA and Depreciation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segments and Related Information [Line Items]
EBITDA	$ 271.8	$ 253.6	$ 694.3	$ 527.4
Depreciation and amortization	118.7	82.6	316.7	210.6
Reportable Segments | Communications
Segments and Related Information [Line Items]
EBITDA	71.6	79.6	193.1	206.8
Depreciation and amortization	26.4	21.1	72.0	62.1
Reportable Segments | Clean Energy and Infrastructure
Segments and Related Information [Line Items]
EBITDA	13.8	34.4	40.2	69.5
Depreciation and amortization	13.0	5.0	31.1	13.7
Reportable Segments | Oil and Gas
Segments and Related Information [Line Items]
EBITDA	170.6	160.4	476.2	315.0
Depreciation and amortization	55.5	47.5	163.8	107.7
Reportable Segments | Electrical Transmission
Segments and Related Information [Line Items]
EBITDA	34.9	9.1	47.8	14.2
Depreciation and amortization	21.1	6.2	41.3	18.6
Reportable Segments | Other
Segments and Related Information [Line Items]
EBITDA	7.5	7.6	23.3	22.5
Depreciation and amortization	0.0	0.0	0.0	0.0
Corporate
Segments and Related Information [Line Items]
EBITDA	(26.6)	(37.5)	(86.3)	(100.6)
Depreciation and amortization	$ 2.7	$ 2.8	$ 8.5	$ 8.5