Business Consolidation and Other Activities (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Business consolidation and other activities
Business consolidation and other activities	$ 65.6		$ (8.6)		$ 13.6	$ (8.6)
Assets held for sale in connection with facilities closures	5.5				5.5		$ 11.7
Operating Segments | Metal beverage packaging, Americas and Asia
Business consolidation and other activities
Business consolidation and other activities	(0.3)		(3.0)		(2.6)	1.8
Business reorganization activities in the company's metal beverage packaging, Asia, operations, and for ongoing costs					2.6
Compensation received for reimbursement of severance costs incurred in connection with facilities closure and relocation				$ 5.0
Gain on sale of facilities				0.8
Charges related to facilities closure						1.8
Charges related to a fire at company's metal beverage container plants			2.2
Operating Segments | Metal beverage packaging, Europe
Business consolidation and other activities
Business consolidation and other activities	(5.3)		(1.1)		(7.3)	(2.3)
Business reorganization activities in the company's metal beverage packaging, Asia, operations, and for ongoing costs					0.7
Charges incurred in connection with write down of fixed assets held for sale	4.7
Charge incurred in connection with headcount reductions, cost-out initiatives and relocation of the company's European headquarters from Germany to Switzerland	0.6	$ 1.3
Tax expense related to relocation of the company's European headquarters from Germany to Switzerland	1.6	1.7
Operating Segments | Metal food & household products packaging
Business consolidation and other activities
Business consolidation and other activities	(0.7)		(4.0)		(0.9)	(7.1)
Charges related to facilities closure			1.7	2.0
Charges for other insignificant activities			2.3	1.1
Operating Segments | Metal Beverage Packaging, Europe, and Corporate
Business consolidation and other activities
Charges for other insignificant activities						1.0
Charge incurred in connection with headcount reductions, cost-out initiatives and relocation of the company's European headquarters from Germany to Switzerland			1.1	1.2
Tax expense related to relocation of the company's European headquarters from Germany to Switzerland			2.0	$ 2.1
Operating Segments | Aerospace & technologies
Business consolidation and other activities
Business consolidation and other activities					0.7
Corporate and Other Costs
Business consolidation and other activities
Business consolidation and other activities	71.9		$ (0.5)		23.7	$ (1.0)
Charges for other insignificant activities					$ 0.5
Corporate and Other Costs | Rexam PLC
Business consolidation and other activities
Professional Services And Other Costs	23.9	20.2
Recognized Gains (Losses) of associated with its collar and option contracts	$ 96.0	$ (27.7)