0000001 - Document - Cover link:presentationLink link:calculationLink link:definitionLink 0000002 - Statement - Statements of Net Assets Available for Benefits link:presentationLink link:calculationLink link:definitionLink 0000003 - Statement - Statements of Changes in Net Assets Available for Benefits link:presentationLink link:calculationLink link:definitionLink 0000004 - Disclosure - Description of Plan and Significant Accounting Policies link:presentationLink link:calculationLink link:definitionLink 0000005 - Disclosure - A. O. Smith Corporation Master Trust link:presentationLink link:calculationLink link:definitionLink 0000006 - Disclosure - Fair value measurements link:presentationLink link:calculationLink link:definitionLink 0000007 - Disclosure - Income Tax Status link:presentationLink link:calculationLink link:definitionLink 0000008 - Disclosure - Plan Termination link:presentationLink link:calculationLink link:definitionLink 0000009 - Disclosure - Risks and Uncertainties link:presentationLink link:calculationLink link:definitionLink 0000010 - Disclosure - Party-in-Interest and Related Party Transactions link:presentationLink link:calculationLink link:definitionLink 0000011 - Disclosure - Schedule H, line 4i - Schedule of Assets Held (at End of Year) link:presentationLink link:calculationLink link:definitionLink 0000012 - Disclosure - Description of Plan and Significant Accounting Policies (Policies) link:presentationLink link:calculationLink link:definitionLink 0000013 - Disclosure - A. O. Smith Corporation Master Trust (Tables) link:presentationLink link:calculationLink link:definitionLink 0000014 - Disclosure - Fair value measurements (Tables) link:presentationLink link:calculationLink link:definitionLink 0000015 - Disclosure - Description of Plan and Significant Accounting Policies (Details) link:presentationLink link:calculationLink link:definitionLink 0000016 - Disclosure - A. O. Smith Corporation Master Trust - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink 0000017 - Disclosure - A. O. Smith Corporation Master Trust - Investments in Master Trust (Details) link:presentationLink link:calculationLink link:definitionLink 0000018 - Disclosure - A. O. Smith Corporation Master Trust - Fair Value of Investments and Investment Income for the Master Trust (Details) link:presentationLink link:calculationLink link:definitionLink 0000019 - Disclosure - A. O. Smith Corporation Master Trust - Investments at Fair Value by Classification (Details) link:presentationLink link:calculationLink link:definitionLink 0000020 - Disclosure - A. O. Smith Corporation Master Trust - Investments Measured at Fair Value Based on NAV Per Share (Details) link:presentationLink link:calculationLink link:definitionLink 0000021 - Disclosure - Fair value measurements (Details) link:presentationLink link:calculationLink link:definitionLink 0000022 - Disclosure - Party-in-Interest and Related Party Transactions (Details) link:presentationLink link:calculationLink link:definitionLink 0000023 - Disclosure - Schedule H, line 4i - Schedule of Assets Held (at End of Year) (Details) link:presentationLink link:calculationLink link:definitionLink