Increase in percentage points added to the reference rate to compute the variable rate on the debt instrument.

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- Definition

Debt Instrument, Incremental Decrease in Basis Spread on Variable Rate Resulting from Upgrades

+ References

No definition available.

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- Definition

Debt Instrument, Incremental Increase in Basis Spread on Variable Rate Resulting from Downgrades

+ References

No definition available.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM format.

+ References

No definition available.

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- Definition

Purchase Of Note Principal

+ References

No definition available.

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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

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ 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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
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- Definition

Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (g)
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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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- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
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- Definition

Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.

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

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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ 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 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Debt (Senior Notes - Narrative) (Details) - USD ($) $ in Millions	1 Months Ended				3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Jul. 31, 2016	Nov. 30, 2015	Jan. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Net loss on extinguishment of debt	$ 59.0				$ (59.0)	$ (51.0)	$ (11.0)	$ (70.0)	$ (51.0)
Payment of debt extinguishment costs	53.0
Unamortized debt expense	35.0				35.0			35.0		$ 28.0
Repayments of long-term debt								1,139.0	$ 1,175.0
Long-term Debt [Member]
Debt Instrument [Line Items]
Unamortized debt expense	$ 35.0				$ 35.0			$ 35.0		$ 28.0
Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt				$ 2,200.0
Purchase of note principal		$ 700.0
Senior Notes [Member] \| Over LIBOR [Member]
Debt Instrument [Line Items]
Incremental increase in basis points resulting from downgrades								0.25%
Incremental decrease in basis points resulting from upgrades								0.25%
Increase in basis spread		1.75%
3.30% Senior Notes due January 2018 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes				$ 350.0
Stated interest rate		5.05%		3.30%						3.30%
Maturity date, year and month				2018-01						2018-01
Unamortized debt expense
Repayments of long-term debt							$ 38.0	$ 38.0
4.05% Senior Notes due January 2020 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes				$ 850.0
Stated interest rate	4.05%	5.80%		4.05%	4.05%			4.05%		4.05%
Maturity date, year and month				2020-01				2020-01		2020-01
Unamortized debt expense										$ 5.0
Repayments of long-term debt	$ 758.0							$ 758.0
4.95% Senior Notes due January 2025 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes				$ 1,000.0
Stated interest rate	4.95%	6.70%		4.95%	4.95%			4.95%		4.95%
Maturity date, year and month				2025-01				2025-01		2025-01
Unamortized debt expense	$ 6.0				$ 6.0			$ 6.0		$ 7.0
7.50% Senior Notes due February 2018 [Member]
Debt Instrument [Line Items]
Maturity date, year and month								2018-02
7.50% Senior Notes due February 2018 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate							7.50%			7.50%
Maturity date, year and month										2018-02
Unamortized debt expense
Repayments of long-term debt							$ 212.0	$ 212.0
7.15% Senior Notes due June 2018 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate							7.15%			7.15%
Maturity date, year and month								2018-06		2018-06
Unamortized debt expense
Repayments of long-term debt							$ 26.0	$ 26.0
7.50% Senior Notes due April 2026 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes	$ 650.0				$ 650.0			$ 650.0
Stated interest rate	7.50%				7.50%			7.50%
Maturity date, year and month	2026-04							2026-04
Unamortized debt expense	$ 10.0				$ 10.0			$ 10.0
2015 Term Loan due December 2020 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Maturity date, year and month										2020-12
Debt instrument, term			3 years
Unamortized debt expense										$ 2.0
Repayments of long-term debt	327.0	$ 375.0						327.0		$ 423.0
7.75% Senior Notes due October 2027 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Senior notes	$ 500.0				$ 500.0			$ 500.0
Stated interest rate	7.75%				7.75%			7.75%
Maturity date, year and month	2027-10							2027-10
Unamortized debt expense	$ 7.0				$ 7.0			$ 7.0
2026 and 2027 Notes [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 1,100.0
4.10% Senior Notes due March 2022 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate	4.10%				4.10%			4.10%		4.10%
Maturity date, year and month								2022-03		2022-03
Unamortized debt expense	$ 4.0				$ 4.0			$ 4.0		$ 4.0
Maximum [Member] \| 3.30% Senior Notes due January 2018 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate	5.30%				5.30%			5.30%
Maximum [Member] \| 4.05% Senior Notes due January 2020 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate	6.05%				6.05%			6.05%
Maximum [Member] \| 4.95% Senior Notes due January 2025 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Stated interest rate	6.95%				6.95%			6.95%