Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 89.3	$ (67.6)	$ (117.0)
Other comprehensive income (loss), net:
Pension liability adjustment, net of tax (provision) benefit of $(9.8), $0.4, and $(0.1) in 2017, 2016 and 2015, respectively	15.2	(0.6)	(0.4)
Net unrealized gains (losses) on qualifying cash flow hedges, net of tax (provision) benefit of $0.4, $(1.7) and $(0.3) in 2017, 2016 and 2015, respectively	(0.7)	3.3	(0.6)
Foreign currency translation adjustments	0.5	(50.9)	(132.9)
Other comprehensive Income (loss), net	15.0	(48.2)	(133.9)
Total comprehensive income (loss)	104.3	(115.8)	(250.9)
Less: Total comprehensive loss attributable to noncontrolling interests	0.0	(0.4)	(34.3)
Total comprehensive income (loss) attributable to SPX Corporation common shareholders	$ 104.3	$ (115.4)	$ (216.6)