Forward starting interest rate swap agreement, fixed rate

No definition available.

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- Definition

The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

+ References

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 21

-Paragraph 16, 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Interest rate stated in the contractual debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	na
Period Type:	instant

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

+ References

No definition available.

+ Details

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

- Definition

For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.

+ References

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

-Publisher SEC

-Name Industry Guide

-Number 3

-Section VII

-Subsection 2

+ Details

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Balance Type:	credit
Period Type:	duration

Debt (Narrative) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		9 Months Ended
	Sep. 30, 2012	Feb. 28, 2010	Sep. 30, 2011 Commercial Paper [Member]	Sep. 30, 2012 Seven Hundred Fifty Million Fixed Rate Notes Due March Two Thousand Twenty Two, Interest Equal To Three Point Zero Percent [Member] [Member]	Sep. 30, 2012 Seven Hundred Fifty Million Fixed Rate Notes Due August Two Thousand Thirteen, Interest Equal To Five Point Four Zero Percent [Member]
Debt Instrument [Line Items]
Forward starting interest rate swap agreement fixed rate	3.32%	4.46%
Debt instrument, face amount				$ 750.0	$ 750.0
Debt Instrument, Interest Rate, Stated Percentage				3.00%	5.40%
Weighted average balance, at par value, of commercial paper outstanding			41.0
Maximum month-end balance for commercial paper			$ 200.0