Legal Matters and Contingencies (Details)	3 Months Ended
Mar. 31, 2012 sites
Legal Matters and Contingencies
Number of former public waste disposal sites	7
Oil-for-Food Program [Member]
Legal Matters and Contingencies
Number of French companies for investigation	170
Number of participants in U.N Oil-for-Food Program	93
Number of foreign subsidiaries	2

Number of foreign subsidiaries in Oil for Food Program.

No definition available.

Name:	fls_NumberOfForeignSubsidiariesInOilForFoodProgram
Namespace Prefix:	fls_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration