Derivatives (Schedule of Derivative Assets Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Fair value of derivative assets — current	$ 14.3us-gaap_DerivativeAssetsCurrent	$ 16.7us-gaap_DerivativeAssetsCurrent
Fair value of derivative assets — long term	7.6us-gaap_DerivativeAssetsNoncurrent	10.0us-gaap_DerivativeAssetsNoncurrent
Fair value of derivative liabilities — current	(3.0)us-gaap_DerivativeLiabilitiesCurrent	(3.0)us-gaap_DerivativeLiabilitiesCurrent
Fair value of derivative liabilities — long term	(1.5)us-gaap_DerivativeLiabilitiesNoncurrent	(2.0)us-gaap_DerivativeLiabilitiesNoncurrent
Net fair value of derivatives	17.4	21.7
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Net fair value of derivatives	$ 17.4

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details