Investment in Unconsolidated Affiliates Summarized Income Statement of Equity Method Investment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Schedule of Equity Method Investments [Line Items]
Operating revenues	$ 616.0	$ 1,002.0
Cost of sales	292.0	633.0
Operating income	104.0	162.0
Net income	$ 91.0	$ 149.0

The amount of net income (loss) reported by an equity method investment of the entity.

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