EQUITY AND STOCK-BASED COMPENSATION (Details 6) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended						9 Months Ended
	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Sep. 28, 2013	Sep. 29, 2012
Dividends
Dividends declared, per share (in dollars per share)	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25
Changes in Equity
Balance	$ 2,011.6		$ 2,280.0	$ 2,175.3		$ 2,237.3	$ 2,280.0	$ 2,237.3
Net income (loss)	62.1			60.2			106.5	121.2
Net unrealized gains on qualifying cash flow hedges, net of tax provision	2.3			0.5			1.2	1.1
Net unrealized gains on qualifying cash flow hedges, tax provision	1.0			0.3			0.6	0.6
Net unrealized losses on available-for-sale securities	(0.8)			(2.9)			(1.5)	(1.5)
Pension liability adjustment, net of tax provision	3.2			3.7			18.4	13.2
Pension liability adjustment, tax provision	3.3			2.5			10.9	7.6
Foreign currency translation adjustments	70.8			78.1			(2.8)	0.9
Total comprehensive income (loss), net	137.6			139.6			121.8	134.9
Dividends declared	(11.4)	(11.5)	(11.4)	(12.7)	(12.7)	(12.8)	(34.3)	(38.2)
Exercise of stock options and other incentive plan activity	3.7			4.6			18.1	23.2
Exercise of stock options and other incentive plan activity, tax benefit				0.1			5.8	3.6
Amortization of restricted stock and restricted stock unit grants	3.7			6.0			29.3	34.9
Amortization of restricted stock and stock unit grants relating to discontinued operations				0.4				1.0
Restricted stock and restricted stock unit vesting, net of tax withholdings	(2.0)						(22.3)	(4.3)
Common stock repurchases							(249.0)	(75.0)
Dividends attributable to noncontrolling interests				(0.7)				(0.7)
Other changes in noncontrolling interests	(1.7)						(2.1)
Balance	2,141.5	2,011.6		2,312.1	2,175.3		2,141.5	2,312.1
SPX Corporation Shareholders' Equity
Changes in Equity
Balance	1,998.7		2,268.7	2,165.2		2,227.3	2,268.7	2,227.3
Net income (loss)	62.9			57.8			104.0	118.7
Net unrealized gains on qualifying cash flow hedges, net of tax provision	2.3			0.5			1.2	1.1
Net unrealized losses on available-for-sale securities	(0.8)			(2.9)			(1.5)	(1.5)
Pension liability adjustment, net of tax provision	3.2			3.7			18.4	13.2
Foreign currency translation adjustments	70.1			77.8			(2.2)	0.6
Total comprehensive income (loss), net	137.7			136.9			119.9	132.1
Dividends declared	(11.4)			(12.7)			(34.3)	(38.2)
Exercise of stock options and other incentive plan activity	3.7			4.6			18.1	23.2
Amortization of restricted stock and restricted stock unit grants	3.7			6.0			29.3	34.9
Restricted stock and restricted stock unit vesting, net of tax withholdings	(2.0)						(22.3)	(4.3)
Common stock repurchases							(249.0)	(75.0)
Other changes in noncontrolling interests	(3.0)						(3.0)
Balance	2,127.4			2,300.0			2,127.4	2,300.0
Noncontrolling Interests
Changes in Equity
Balance	12.9		11.3	10.1		10.0	11.3	10.0
Net income (loss)	(0.8)			2.4			2.5	2.5
Foreign currency translation adjustments	0.7			0.3			(0.6)	0.3
Total comprehensive income (loss), net	(0.1)			2.7			1.9	2.8
Dividends attributable to noncontrolling interests				(0.7)				(0.7)
Other changes in noncontrolling interests	1.3						0.9
Balance	$ 14.1			$ 12.1			$ 14.1	$ 12.1