Indebtedness (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended																			12 Months Ended															12 Months Ended			12 Months Ended						12 Months Ended												12 Months Ended												12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012 Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Between 2.00 to 1.00 and 3.00 to 1.00 Minimum	Dec. 31, 2012 Between 2.00 to 1.00 and 3.00 to 1.00 Maximum	Dec. 31, 2012 Between 1.50 to 1.00 and 2.00 to 1.00 Minimum	Dec. 31, 2012 Between 1.50 to 1.00 and 2.00 to 1.00 Maximum	Dec. 31, 2012 Between 1.00 to 1.00 and 1.50 to 1.00 Minimum	Dec. 31, 2012 Between 1.00 to 1.00 and 1.50 to 1.00 Maximum	Dec. 31, 2012 Less than 1.00 to 1.00	Dec. 31, 2012 Alternate Base Rate Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Alternate Base Rate Between 2.00 to 1.00 and 3.00 to 1.00	Dec. 31, 2012 Alternate Base Rate Between 1.50 to 1.00 and 2.00 to 1.00	Dec. 31, 2012 Alternate Base Rate Between 1.00 to 1.00 and 1.50 to 1.00	Dec. 31, 2012 Alternate Base Rate Less than 1.00 to 1.00	Dec. 31, 2012 Reserve adjusted LIBOR rate Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Reserve adjusted LIBOR rate Between 2.00 to 1.00 and 3.00 to 1.00	Dec. 31, 2012 Reserve adjusted LIBOR rate Between 1.50 to 1.00 and 2.00 to 1.00	Dec. 31, 2012 Reserve adjusted LIBOR rate Between 1.00 to 1.00 and 1.50 to 1.00	Dec. 31, 2012 Reserve adjusted LIBOR rate Less than 1.00 to 1.00	Dec. 31, 2010 Interest Rate Swaps	Dec. 31, 2012 Letter of credit	Dec. 31, 2012 Letter of credit Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Letter of credit Between 2.00 to 1.00 and 3.00 to 1.00	Dec. 31, 2012 Letter of credit Between 1.50 to 1.00 and 2.00 to 1.00	Dec. 31, 2012 Letter of credit Between 1.00 to 1.00 and 1.50 to 1.00	Dec. 31, 2012 Letter of credit Less than 1.00 to 1.00	Dec. 31, 2012 Senior credit facility quarter D	Dec. 31, 2012 Senior credit facility Minimum	Dec. 31, 2012 Senior credit facility Maximum	Dec. 31, 2012 Senior credit facility Debt Instrument, variable prime rate	Dec. 31, 2012 Senior credit facility Federal funds alternative base rate	Dec. 31, 2012 Senior credit facility LIBOR alternative base rate	Dec. 31, 2012 Senior credit facility Reserve adjusted LIBOR rate	Dec. 31, 2012 Senior credit facility Letter of credit	Dec. 31, 2012 Term loan 2	Dec. 31, 2012 Domestic and global revolving credit facilities	Dec. 31, 2012 Domestic revolving credit facility	Dec. 31, 2012 Domestic revolving credit facility Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Domestic revolving credit facility Between 2.00 to 1.00 and 3.00 to 1.00	Dec. 31, 2012 Domestic revolving credit facility Between 1.50 to 1.00 and 2.00 to 1.00	Dec. 31, 2012 Domestic revolving credit facility Between 1.00 to 1.00 and 1.50 to 1.00	Dec. 31, 2012 Domestic revolving credit facility Less than 1.00 to 1.00	Dec. 31, 2012 Global revolving credit facility	Dec. 31, 2012 Global revolving credit facility Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Global revolving credit facility Between 2.00 to 1.00 and 3.00 to 1.00	Dec. 31, 2012 Global revolving credit facility Between 1.50 to 1.00 and 2.00 to 1.00	Dec. 31, 2012 Global revolving credit facility Between 1.00 to 1.00 and 1.50 to 1.00	Dec. 31, 2012 Global revolving credit facility Less than 1.00 to 1.00	Dec. 31, 2012 Foreign credit instrument facility Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Foreign credit instrument facility Between 2.00 to 1.00 and 3.00 to 1.00	Dec. 31, 2012 Foreign credit instrument facility Between 1.50 to 1.00 and 2.00 to 1.00	Dec. 31, 2012 Foreign credit instrument facility Between 1.00 to 1.00 and 1.50 to 1.00	Dec. 31, 2012 Foreign credit instrument facility Less than 1.00 to 1.00	Dec. 31, 2012 Participation foreign credit instrument facility	Dec. 31, 2012 Letters of credit under separate arrangements in China, South Africa, and India	Dec. 31, 2012 Term loan	Dec. 31, 2012 Term loan LIBOR alternative base rate Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Term loan LIBOR alternative base rate Between 2.00 to 1.00 and 3.00 to 1.00	Dec. 31, 2012 Term loan LIBOR alternative base rate Between 1.50 to 1.00 and 2.00 to 1.00	Dec. 31, 2012 Term loan LIBOR alternative base rate Between 1.00 to 1.00 and 1.50 to 1.00	Dec. 31, 2012 Term loan LIBOR alternative base rate Less than 1.00 to 1.00	Dec. 31, 2012 Term loan Reserve adjusted LIBOR rate Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Term loan Reserve adjusted LIBOR rate Between 2.00 to 1.00 and 3.00 to 1.00	Dec. 31, 2012 Term loan Reserve adjusted LIBOR rate Between 1.50 to 1.00 and 2.00 to 1.00	Dec. 31, 2012 Term loan Reserve adjusted LIBOR rate Between 1.00 to 1.00 and 1.50 to 1.00	Dec. 31, 2012 Term loan Reserve adjusted LIBOR rate Less than 1.00 to 1.00	Dec. 31, 2012 Foreign Credit Commitment	Dec. 31, 2012 Foreign Credit Commitment Greater than or equal to 3.00 to 1.00	Dec. 31, 2012 Foreign Credit Commitment Between 2.00 to 1.00 and 3.00 to 1.00	Dec. 31, 2012 Foreign Credit Commitment Between 1.50 to 1.00 and 2.00 to 1.00	Dec. 31, 2012 Foreign Credit Commitment Between 1.00 to 1.00 and 1.50 to 1.00	Dec. 31, 2012 Foreign Credit Commitment Less than 1.00 to 1.00	Dec. 31, 2012 Foreign Credit Commitment Letter of credit
Credit Facilities
Maximum borrowing capacity under financing arrangement																											$ 2,600.0										$ 300.0						$ 300.0											$ 1,000.0
Percentage of initial principal amount which the entity will repay in 2014																																			15.00%
Percentage of initial principal amount which the entity will repay in 2015																																			20.00%
Percentage of initial principal amount which the entity will repay at the end of the first fiscal quarter of 2016																																			5.00%
Termination costs of swap and term loan under previously existing senior credit facilities																				25.6
Write-off of deferred financing costs																				1.1
Costs associated with early termination of swaps																				24.3
Early termination fee																				0.2
Amount of available borrowing capacity																																				533.6																															414.3
Letters of credit issued, amount outstanding																																		66.4																					7.2																		785.7
Additional commitments SPX may seek to add																											525.0
Maximum amount of the availability resets																											1,000.0
Basis spread on variable rate (as a percent)										1.00%	0.875%	0.75%	0.50%	0.25%	2.00%	1.875%	1.75%	1.50%	1.25%												0.50%	1.00%																									1.25%	1.125%	1.00%	0.75%	0.50%	2.25%	2.125%	2.00%	1.75%	1.50%
Description of variable rate (as a percent)																														prime rate	federal funds effective rate	one-month LIBOR rate	reserve-adjusted LIBOR rate
Interest period which may be elected, shortest (in months)																																	1M
Interest period which may be elected, second shortest (in months)																																	2M
Interest period which may be elected, second longest (in months)																																	3M
Interest period which may be elected, longest (in months)																																	6M
Threshold amount of cash and cash equivalents above which amounts are netted against consolidated net debt for calculation of debt compliance	50.0
Consolidated leverage ratio, range		3.00							1.00
Consolidated leverage ratio			2.00	3.00	1.50	2.00	1.00	1.50
Commitment fee (as a percent)																						2.00%	1.875%	1.75%	1.50%	1.25%												0.40%	0.35%	0.30%	0.275%	0.25%		0.40%	0.35%	0.30%	0.275%	0.25%	1.25%	1.125%	1.00%	0.875%	0.75%			0.50%												0.40%	0.35%	0.30%	0.275%	0.25%
Weighted-average interest rate of senior credit facilities (as a percent)																											2.40%
Commitment fee on daily unused amount (as a percent)																																																								0.275%
Fronting fees (as a percent)																					0.125%																																	0.20%
Maximum period within which net proceeds should be reinvested (in days)																											360
Security interest granted in capital stock of domestic subsidiaries or subsidiary guarantors (as a percent)																											100.00%
Security interest granted in material first tier foreign subsidiaries (as a percent)																											65.00%
Number of trailing fiscal quarters used in calculating the Consolidated Interest Coverage Ratio under senior credit facilities' covenants (in number of quarters)																											4
Number of trailing fiscal quarters used in calculating the Consolidated Leverage Coverage Ratio under senior credit facilities' covenants (in number of quarters)																											4
Prepayment reinvestment exclusion period (in days)																											360
Consolidated Interest Coverage Ratio under senior credit facilities' covenants																												3.50
Consolidated Leverage Ratio under senior credit facilities' covenants																													3.25
Consolidated Leverage Ratio under senior credit facilities' covenants after certain permitted acquisitions																											3.50
Maximum consolidated Leverage Ratio necessary for unlimited amount of capital stock repurchases and dividend payments under senior credit facilities' covenants																													2.50
Consolidated Leverage Ratio restricting amount of capital stock repurchases and dividend payments under senior credit facilities' covenants																												2.50
Maximum amount of capital stock repurchases and dividend declarations allowable (before adjustment) under senior credit facilities' covenants in any fiscal year if Consolidated Leverage Ratio is greater than or equal to 2.50 to 1.00																											100.0
Consolidated leverage ratio greater than 2.50 to 1.00 - capital stock repurchases and dividend declarations used in calculation																											$ 300.0
Percentage of cumulative consolidated net income during the period from July 1, 2011 to the end of the most recent fiscal quarter used																											50.00%
Percentage of consolidated net deficit removed from calculation of amounts available for stock repurchases and dividends																											(100.00%)