Face (par) amount of debt instrument at time of issuance.

Reference 1: 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=64930739&loc=d3e28878-108400

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=64930785&loc=d3e28551-108399

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: 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

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12355-112629

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- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

No definition available.

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Debt (Narrative) (Details) - USD ($)			3 Months Ended	9 Months Ended
Debt (Narrative) (Details) - USD ($)	May 21, 2016	Apr. 08, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Gain (loss) on the redemption of debt	$ (86,100,000)		$ (5,600,000)	$ (86,100,000)	$ (24,100,000)
Senior debentures maturing April 15, 2026 [Member]
Debt Instrument [Line Items]
Aggregate principal amount		$ 375,000,000
Debt instrument interest rate		4.50%
Proceeds from Issuance of Debt		$ 370,500,000
Senior debentures maturing March 1, 2020 [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	7.50%
Senior debentures maturing June 15, 2021 [Member]
Debt Instrument [Line Items]
Debt instrument interest rate	6.375%