Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 M businessunit	Dec. 31, 2010	Dec. 31, 2009
Foreign Currency Translation
Foreign currency transaction gains and losses	$ 41.4	$ 27.5	$ 21.2
Cash Equivalents
Maximum term of original maturity to classify instruments as cash equivalents (in months)	3
Revenue Recognition
Number of business units in which sales incentive programs are significant	1
Costs and estimated earnings on uncompleted contracts
Costs incurred on uncompleted contracts	2,783.5	2,394.7
Estimated earnings to date	750.6	662.9
Aggregate costs incurred on uncompleted contracts and estimated earnings to date	3,534.1	3,057.6
Less: Billings to date	(3,514.4)	(3,203.4)
Net costs and estimated earnings in excess of billings (billings in excess of costs and estimated earnings)	19.7	(145.8)
Net costs and estimated earnings in excess of billings assumed in the acquisition of Clyde Union (Holdings) S.A.R.L. ("Clyde Union")	57.2
"Net costs and estimated earnings in excess of billings after the acquisition of Clyde Union (Holdings) S.A.R.L. (""Clyde Union"")"	76.9	(145.8)
Billings in excess of costs and estimated earnings
Costs and estimated earnings in excess of billings	355.9	228.1
Billings in excess of costs and estimated earnings on uncompleted contracts	(279.0)	(373.9)
Net costs and estimated earnings in excess of billings (billings in excess of costs and estimated earnings)	76.9	(145.8)
Costs and estimated earnings in excess of billings on contracts reported as a component of accounts receivable, net	355.9	226.3
Costs and estimated earnings in excess of billings on contracts reported as a component of other long-term assets	0	1.8
Billings in excess of costs and estimated earnings on uncompleted contracts reported as a component of accrued expenses	275.4	364.5
Billings in excess of costs and estimated earnings on uncompleted contracts reported as a component of other long-term liabilities	3.6	9.4
Research and Development Costs
Research and development expense	53.0	47.2	42.4
Property, plant and equipment
Depreciation expense	64.3	62.4	60.1
Interest capitalized	$ 1.3	$ 3.9
Building
Property, plant and equipment
Useful lives of property, plant and equipment, high end of range (in years)	40
Machinery and equipment
Property, plant and equipment
Useful lives of property, plant and equipment, low end of range (in years)	3
Useful lives of property, plant and equipment, high end of range (in years)	15