Effect of Accounting Changes (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended											0 Months Ended
	Dec. 31, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 31, 2012	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Domestic Pension Plans	Dec. 31, 2013 Historical method	Dec. 31, 2013 Historical method Domestic Pension Plans	Dec. 31, 2012 As Revised and Restated	Dec. 31, 2011 As Revised and Restated	Dec. 31, 2013 Effect of Change	Dec. 31, 2012 Effect of Change	Dec. 31, 2011 Effect of Change	Jan. 02, 2011 Adoption of new accounting method Effect of Change
Consolidated Statements of Operations:
Cost of products sold									$ 3,359.6	$ 3,517.4	$ 3,066.4		$ 3,388.4		$ 3,511.6	$ 3,065.6	$ (28.8)	$ 5.8	$ 0.8
Selling, general and administrative									956.0	1,112.6	897.4		1,370.5		999.1	882.1	(414.5)	113.5	15.3
Operating income (loss)									329.6	(142.4)	237.0		(113.7)		(23.1)	253.1	443.3	(119.3)	(16.1)
Income (loss) from continuing operations before income taxes									256.1	(197.9)	120.4		(187.2)		(78.6)	136.5	443.3	(119.3)	(16.1)
Income tax (provision) benefit									(54.8)	21.3	12.3		115.8		(21.0)	8.2	(170.6)	42.3	4.1
Income (loss) from continuing operations	84.4	63.1	39.2	14.6	(275.7)	53.8	35.5	9.8	201.3	(176.6)	132.7		(71.4)		(99.6)	144.7	272.7	(77.0)	(12.0)
Income from discontinued operations	2.5	5.4	8.0	(4.6)	321.0	12.0	18.2	8.6	11.3	359.8	43.5		8.2		360.2	51.6	3.1	(0.4)	(8.1)
Net income (loss)	86.9	68.5	47.2	10.0	45.3	65.8	53.7	18.4	212.6	183.2	176.2		(63.2)		260.6	196.3	275.8	(77.4)	(20.1)
Net income (loss) attributable to SPX Corporation common shareholders	87.0	69.3	45.2	8.7	45.0	63.4	52.9	19.1	210.2	180.4	171.2		(65.6)		257.8	191.3	275.8	(77.4)	(20.1)
Amounts attributable to SPX Corporation common shareholders:
Income (loss) from continuing operations, net of tax									199.1	(179.6)	127.7		(73.6)		(102.6)	139.7	272.7	(77.0)	(12.0)
Income from discontinued operations, net of tax									11.1	360.0	43.5		8.0		360.4	51.6	3.1	(0.4)	(8.1)
Net income attributable to SPX Corporation common shareholders	87.0	69.3	45.2	8.7	45.0	63.4	52.9	19.1	210.2	180.4	171.2		(65.6)		257.8	191.3	275.8	(77.4)	(20.1)
Basic income (loss) per share of common stock:
Continuing operations (in dollars per share)	$ 1.89	$ 1.43	$ 0.81	$ 0.29	$ (5.56)	$ 1.03	$ 0.69	$ 0.21	$ 4.39	$ (3.59)	$ 2.53		$ (1.62)		$ (2.05)	$ 2.77	$ 6.01	$ (1.54)	$ (0.24)
Discontinued operations, net of tax (in dollars per share)	$ 0.05	$ 0.12	$ 0.18	$ (0.10)	$ 6.47	$ 0.24	$ 0.37	$ 0.17	$ 0.24	$ 7.20	$ 0.86		$ 0.17		$ 7.20	$ 1.02	$ 0.07		$ (0.16)
Net income per share attributable to SPX Corporation common shareholders (in dollars per share)	$ 1.94	$ 1.55	$ 0.99	$ 0.19	$ 0.91	$ 1.27	$ 1.06	$ 0.38	$ 4.63	$ 3.61	$ 3.39		$ (1.45)		$ 5.15	$ 3.79	$ 6.08	$ (1.54)	$ (0.40)
Diluted income (loss) per share of common stock:
Continuing operations (in dollars per share)	$ 1.85	$ 1.42	$ 0.81	$ 0.28	$ (5.56)	$ 1.03	$ 0.68	$ 0.20	$ 4.33	$ (3.59)	$ 2.51		$ (1.62)		$ (2.05)	$ 2.74	$ 5.95	$ (1.54)	$ (0.23)
Discontinued operations, net of tax (in dollars per share)	$ 0.06	$ 0.12	$ 0.17	$ (0.10)	$ 6.47	$ 0.24	$ 0.36	$ 0.17	$ 0.24	$ 7.20	$ 0.85		$ 0.17		$ 7.20	$ 1.01	$ 0.07		$ (0.16)
Net income per share attributable to SPX Corporation common shareholders (in dollars per share)	$ 1.91	$ 1.54	$ 0.98	$ 0.18	$ 0.91	$ 1.27	$ 1.04	$ 0.37	$ 4.57	$ 3.61	$ 3.36		$ (1.45)		$ 5.15	$ 3.75	$ 6.02	$ (1.54)	$ (0.39)
Consolidated Statements of Comprehensive Income:
Net income (loss)	86.9	68.5	47.2	10.0	45.3	65.8	53.7	18.4	212.6	183.2	176.2		(63.2)		260.6	196.3	275.8	(77.4)	(20.1)
Pension liability adjustment, net of tax									(2.2)	(1.0)	(2.1)		(278.0)		(80.3)	(21.7)	(275.8)	79.3	19.6
Consolidated Balance Sheets / Consolidated Statements of Equity:
Retained earnings	2,303.1				2,138.4				2,303.1	2,138.4	2,008.9		2,541.0		2,652.1	2,445.2	(237.9)	(513.7)	(436.3)
Accumulated other comprehensive income (loss)	287.5				284.8				287.5	284.8	189.8		49.6		(228.9)	(246.5)	237.9	513.7	436.3
Consolidated Statement of Cash Flows:
Net income (loss)	86.9	68.5	47.2	10.0	45.3	65.8	53.7	18.4	212.6	183.2	176.2		(63.2)		260.6	196.3	275.8	(77.4)	(20.1)
Less: Income from discontinued operations, net of tax	2.5	5.4	8.0	(4.6)	321.0	12.0	18.2	8.6	11.3	359.8	43.5		8.2		360.2	51.6	3.1	(0.4)	(8.1)
Income (loss) from continuing operations	84.4	63.1	39.2	14.6	(275.7)	53.8	35.5	9.8	201.3	(176.6)	132.7		(71.4)		(99.6)	144.7	272.7	(77.0)	(12.0)
Deferred and other income taxes									95.0	(43.6)	(39.8)		(75.6)		(1.3)	(35.7)	170.6	(42.3)	(4.1)
Pension and other employee benefits									(0.1)	176.1	72.3		443.2		56.8	56.2	(443.3)	119.3	16.1
Retained earnings																				416.2
Pension and postretirement benefit expense												(17.7)		425.6
Loss that would have been recognized substantially as a result of the settlement														$ 399.4
Percentage of projected benefit obligation														61.00%