Document And Entity Information (USD $)	12 Months Ended
	Jun. 30, 2011	Aug. 12, 2011	Dec. 31, 2010
Document And Entity Information
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jun. 30, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Trading Symbol	crs
Entity Registrant Name	CARPENTER TECHNOLOGY CORP
Entity Central Index Key	0000017843
Current Fiscal Year End Date	--06-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		44,166,401
Entity Public Float			$ 1,758,969,270
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes