Segment Information, Geographic and Product Data (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jun. 30, 2012 item	Jun. 30, 2011 Precision Castparts Corporation item	Jun. 30, 2010 Precision Castparts Corporation item
Segment Information, Geographic and Product Data
Number of reportable segments	3
Major customer disclosure
Number of customers accounted for more than 10% of the sales		1	1
Sales accounted from Precision Castparts as a percentage of total sales		10.00%	10.00%
Sales from major customer accounted for more than 10%		$ 161.7	$ 116.1

Amount of revenue generated from a single external customer that accounts for 10 percent or more of an entity's revenues.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 42

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9054-108599

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 39

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_EntityWideRevenueMajorCustomerAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration