Dividends (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	6 Months Ended
Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Dividends [Abstract]
Total dividends per share for the period		$ 0.3540		$ 0.7075
Total dividends paid for the period	$ 70.4	$ 70.1		$ 139.8
Dividends Payable, Date Declared	Oct. 30, 2013
Dividends Payable, Date to be Paid	Dec. 05, 2013
Dividends Payable, Date of Record	Nov. 21, 2013
Common Stock, Dividends, Per Share, Declared	$ 0.3545	$ 0.3540	$ 0.3510	$ 0.7075	$ 0.7010

Aggregate dividends paid during the period for each share of common stock outstanding.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

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Equity impact of common stock cash dividends declared by an entity during the period. This element includes paid and unpaid dividends declared during the period.

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+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 32

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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