The increase in the fair value of plan assets from contributions made by the employer.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(3)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Retirement Benefits (Narrative) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Sep. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Cash contributions to funded pension plans and benefit payments under unfunded pension plans	$ 238.9	$ 23.4	$ 76.4
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total expected contributions for current fiscal year	280.0
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Total expected contributions for current fiscal year	$ 290.0