XML 44 R62.htm IDEA: XBRL DOCUMENT v2.4.1.9
Employee Incentive Plans, Short Term Incentive Plans (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs      
EVA measurement period 1 year    
Compensation charges associated with STI Plans      
Costs recorded in connection with STI plans $ 12.7kalu_ShortTermIncentiveCompensationExpense $ 15.7kalu_ShortTermIncentiveCompensationExpense $ 14.4kalu_ShortTermIncentiveCompensationExpense
Fabricated Products      
Compensation charges associated with STI Plans      
Costs recorded in connection with STI plans 9.6kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_StatementBusinessSegmentsAxis
= kalu_FabricatedProductsMember		 11.2kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_StatementBusinessSegmentsAxis
= kalu_FabricatedProductsMember		 9.9kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_StatementBusinessSegmentsAxis
= kalu_FabricatedProductsMember
All Other      
Compensation charges associated with STI Plans      
Costs recorded in connection with STI plans 3.1kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_StatementBusinessSegmentsAxis
= kalu_AllOtherMember		 4.5kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_StatementBusinessSegmentsAxis
= kalu_AllOtherMember		 4.5kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_StatementBusinessSegmentsAxis
= kalu_AllOtherMember
Cost of products sold, excluding depreciation and amortization and other items      
Compensation charges associated with STI Plans      
Costs recorded in connection with STI plans 4.7kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember		 4.6kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember		 4.3kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_CostOfSalesMember
Selling, administrative, research and development and general      
Compensation charges associated with STI Plans      
Costs recorded in connection with STI plans $ 8.0kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= kalu_SellingAdministrativeResearchAndDevelopmentAndGeneralExpensesMember		 $ 11.1kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= kalu_SellingAdministrativeResearchAndDevelopmentAndGeneralExpensesMember		 $ 10.1kalu_ShortTermIncentiveCompensationExpense
/ us-gaap_IncomeStatementLocationAxis
= kalu_SellingAdministrativeResearchAndDevelopmentAndGeneralExpensesMember