Investment in Unconsolidated Affiliate Investment in Unconsolidated Affiliate (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013	Jun. 30, 2014		Jun. 30, 2013	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Undistributed Earnings, Basic	$ 7.4			$ 15.3
Equity Method Investments	278.6			278.6			61.1
Distribution of earnings from equity investment				0.7		0
Income from equity investments	4.5		3.4	8.7		4.4
Gulf Coast Fractionators
Schedule of Equity Method Investments [Line Items]
Undistributed Earnings, Basic				13.1
Equity Method Investments	56.0	[1]		56.0	[1]		61.1	[1]
Distribution of earnings from equity investment	0			0	[2]
Equity Method Investment, Ownership Percentage	38.75%			38.75%
Income from equity investments	3.9		3.4	8.0	[2]	4.4
Howard Energy Partners
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	222.6			222.6			0
Distribution of earnings from equity investment	3.0			5.7	[2]
Equity Method Investment, Ownership Percentage	30.60%			30.60%
Income from equity investments	0.6		0	0.7	[2]	0
Total
Schedule of Equity Method Investments [Line Items]
Distribution of earnings from equity investment	3.0			5.7	[2]
Income from equity investments	$ 4.5		$ 3.4	$ 8.7	[2]	$ 4.4

[1] Devon retained $13.1 million of the undistributed earnings due from GCF, as of March 7, 2014 when the GCF contractual right allocating the benefits and burdens of the 38.75% ownership interest in GCF to the Partnership became effective. The $13.1 million of the undistributed earnings was reflected as a reduction in the GCF investment on March 7, 2014.

[2] Includes income and distributions for the period March 7, 2014 through June 30, 2014.