Allowance for Expected Credit Losses - Additional Information (Details)	Dec. 31, 2024
Credit Loss [Abstract]
Contract assets, allowance for credit loss as a percentage of assets	1.00%

Contract With Customer, Asset, Allowance For Credit Loss, Percentage Of Assets

No definition available.

Name:	fls_ContractWithCustomerAssetAllowanceForCreditLossPercentageOfAssets
Namespace Prefix:	fls_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant