Sale of investment EBP, Investment Sold, Plan Interest in Master Trust, Selling Price EBP 020 EBP 020 [Member] EBP 020 Entity tax identification number Entity Tax Identification Number Total investments at fair value Total investments at fair value EBP, Investment, Fair Value Participant rollovers EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover Maximum Maximum [Member] Legal Entity [Axis] Legal Entity [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] EBP, Description of Plan [Table] EBP, Description of Plan [Table] Registered investment companies Mutual Fund [Member] EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Table] Annual compensation on pre-tax EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage EBP, Fully Benefit-Responsive Investment Contract [Table] EBP, Fully Benefit-Responsive Investment Contract [Table] Fees paid for loan services EBP, Party-In-Interest, Fees Paid, Loan Services EBP, Party-In-Interest, Fees Paid, Loan Services Total deductions EBP, Change in Net Asset Available for Benefit, Decrease Maximum borrowing amount EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount Fair Value Measurements EBP, Investment, Fair Value and NAV [Text Block] Minimum borrowing amount EBP, Note Receivable from Participant, Account, Minimum Borrowing, Amount EBP, Fully Benefit-Responsive Investment Contract [Abstract] Investments, at fair value EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value Short-term investment fund Insight Investment Stable Value Fund Money Market Funds [Member] Plan's Divided Interest EBP, Nonconsolidated, Plan Interest in Master Trust [Member] Level 1 Fair Value, Inputs, Level 1 [Member] Fully Benefit-Responsive Investment Contracts EBP, Fully Benefit-Responsive Investment Contract [Text Block] EBP, Investment, Fair Value and NAV [Abstract] Statistical Measurement [Axis] Statistical Measurement [Axis] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Table] Payment of Benefits EBP, Payment to Participant [Policy Text Block] Transfers in Net transfers out EBP, Change in Net Asset Available for Benefit, Transfer to (from) Plan EBP, Master Trust [Line Items] EBP, Master Trust [Line Items] Amendment Flag Amendment Flag Basis of Accounting EBP, Basis of Accounting [Policy Text Block] EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Table] Investment number of shares EBP, Investment, Number of Shares Net increase in net assets available for benefits EBP, Change in Net Asset Available for Benefit, Increase (Decrease), After Transfer To (From) Plan EBP, Change in Net Asset Available for Benefit, Increase (Decrease), After Transfer To (From) Plan EBP, Description of Plan and Accounting Change [Abstract] EBP, Description of Plan and Accounting Change [Abstract] Share price EBP, Investment Share Price EBP, Investment Share Price Schedule of Plan Assets and Investments at Fair Value EBP, Investment, Fair Value and NAV [Table Text Block] Investments [Domain] Investments [Domain] General loan, borrowing term EBP, Note Receivable From Participant, General Loan, Borrowing Term EBP, Note Receivable From Participant, General Loan, Borrowing Term EBP, Master Trust [Abstract] Interest in Carpenter Technology Master Trust, at contract value EBP, Investment, Plan Interest in Master Trust, Contract Value Use of Estimates EBP, Use of Estimate [Policy Text Block] Schedule of Assets (Held at End of Year) EBP, Schedule of Asset Held for Investment [Text Block] Cover [Abstract] Market capitalization amount EBP, Primary Investments, Minimum Market Capitalization At Time Of Initial Investment, Amount EBP, Primary Investments, Minimum Market Capitalization At Time Of Initial Investment, Amount Risks and Uncertainties EBP, Risk and Uncertainty [Text Block] EBP, Synthetic Investment Contract EBP, Synthetic Investment Contract [Member] Purchase of investments EBP, Investment Acquired, Plan Interest in Master Trust, Purchase Price Involuntary cash-out limit EBP, Involuntary Cash-out Limit EBP, Involuntary Cash-out Limit Minimum Minimum [Member] Fees paid for investment management services EBP, Party-In-Interest, Fees Paid, Investment Management Services EBP, Party-In-Interest, Fees Paid, Investment Management Services Constant duration synthetic GICs EBP, Synthetic Investment Contract, Constant Duration [Member] EBP, Synthetic Investment Contract, Constant Duration Investment Type [Axis] Investment Type [Axis] Interest income on notes receivable from participants EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Total contributions EBP, Change in Net Asset Available for Benefit, Increase from Contribution Primary residence, borrowing term EBP, Note Receivable From Participant, Account, Primary Residence, Borrowing Term EBP, Note Receivable From Participant, Account, Primary Residence, Borrowing Term Participants EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Appreciation in fair value of investments EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment Interest and dividends EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment EBP, Description of Plan [Line Items] EBP, Description of Plan [Line Items] Plan number EBP, Plan Number EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Line Items] Description of the Plan EBP, Description of Plan [Text Block] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Domain] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Domain] EBP, Schedule of Asset Held for Investment [Abstract] EBP, Accounting Policy [Table] EBP, Accounting Policy [Table] Total additions EBP, Change in Net Asset Available for Benefit, Increase Investment income: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] Investment, Identifier [Axis] Investment, Identifier [Axis] Administrative expenses EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Asset held for investment EBP, Asset Held for Investment Total investments at contract value EBP, Investment, Contract Value Document Information [Line Items] Document Information [Line Items] EBP, Risk and Uncertainty [Line Items] EBP, Risk and Uncertainty [Line Items] EBP, Risk and Uncertainty [Table] EBP, Risk and Uncertainty [Table] Investment in the Master Trust EBP, Master Trust [Text Block] EBP, Statement of Change in Net Asset Available for Benefit [Abstract] EBP, Fully Benefit-Responsive Investment Contract [Line Items] EBP, Fully Benefit-Responsive Investment Contract [Line Items] Employer EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash and Noncash Annual fixed rate contribution, percentage EBP, Employer Contribution, Annual Fixed Rate Contribution, Percentage EBP, Employer Contribution, Annual Fixed Rate Contribution, Percentage EBP, Tax Status [Table] EBP, Tax Status [Table] Net increase in net assets available for benefits EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Related Party and Party-in-Interest Transactions EBP, Related Party and Party-in-Interest Transactions [Text Block] EBP, Related Party and Party-in-Interest Transactions [Abstract] Total investments EBP, Investment, Fair and Contract Value EBP, Accounting Policy, Accounting Standard Update, and Change in Accounting Principle [Abstract] Automatic deferral rate EBP, Participant Contribution, Automatic, Deferral Rate Aristotle Value Equity CIT B Fund Common Collective Trust, Aristotle Value Equity CIT B Fund [Member] Common Collective Trust, Aristotle Value Equity CIT B Fund Benefits paid to participants EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Dividends EBP, Change in Net Asset Available for Benefit, Increase from Dividend Income on Investment Interest in Carpenter Technology Master Trust, at fair value EBP, Investment, Plan Interest in Master Trust, Fair Value Current value EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] EBP, Statement of Net Asset Available for Benefit [Abstract] EBP, Accounting Policy [Line Items] EBP, Accounting Policy [Line Items] EBP, Tax Status [Abstract] Carpenter Technology Stock Fund Carpenter Technology Stock Fund EBP, Employer, Common Stock Fund [Member] Interest in Carpenter Technology Master Trust Fund income EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Change in Plan Interest in Master Trust Administrative Expenses EBP, Expense [Policy Text Block] Participant loan, current value EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution Investment Valuation and Income Recognition EBP, Investment [Policy Text Block] EBP, Master Trust [Table] EBP, Master Trust [Table] Document Type Document Type Minimum crediting interest rate EBP, Investment, Wrapper Contracts, Guaranteed Minimum Credit Rate, Percentage EBP, Investment, Wrapper Contracts, Guaranteed Minimum Credit Rate, Percentage Plan Termination EBP, Plan Termination [Text Block] Entity Central Index Key Entity Central Index Key Interest rates EBP, Asset Held for Investment, Participant Loan, Interest Rate Common collective trusts Common Collective Trust [Member] EBP, Risk and Uncertainty [Abstract] EBP, Tax Status [Line Items] EBP, Tax Status [Line Items] Notes receivable from participants EBP, Note Receivable from Participant Master Trust EBP, Nonconsolidated, Master Trust [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Summary of Significant Accounting Policies EBP, Summary of Accounting Policy [Text Block] Entity Registrant Name Entity Registrant Name Prime rate EBP, Participant Loan, Basis Spread On Variable Rate EBP, Participant Loan, Basis Spread On Variable Rate Schedule of Investment in Master Trust EBP, Master Trust [Table Text Block] Tax Status EBP, Tax Status [Text Block] Vested account balance percent EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage Document Information [Table] Document Information [Table] Notes Receivable from Participants EBP, Note Receivable from Participant [Policy Text Block] Fixed maturity synthetic GIC EBP, Synthetic Investment Contract, Fixed Maturity [Member] EBP, Synthetic Investment Contract, Fixed Maturity Total investment income Total investment income EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Axis] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Axis] EBP, Related Party and Party-in-Interest Transactions [Line Items] EBP, Related Party and Party-in-Interest Transactions [Line Items] Net assets available for benefits Net assets available for benefits, beginning of year Net assets available for benefits, end of year EBP, Net Asset Available for Benefit Entity [Domain] Entity [Domain] Contributions: EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] Matching percent EBP, Employer Contribution, Matching Percentage NAV Fair Value Measured at Net Asset Value Per Share [Member] EBP, Investment, Fair Value and NAV [Table] EBP, Investment, Fair Value and NAV [Table] Deferrals automatically increase rate EBP, Participant Contribution, Automatic, Annual Increase Deferral Rate EBP, Participant Contribution, Automatic, Annual Increase Deferral Rate EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Line Items]