Equity and Distributions, Noncontrolling Interests (Details) (USD $) In Billions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Noncontrolling Interest
Noncontrolling interests acquired	$ 1.4
Panola Pipeline Company, LLC [Member]
Noncontrolling Interest
Noncontrolling Interest, Ownership Percentage by Parent (in hundredths)	55.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners (in hundredths)	45.00%
Anadarko Petroleum Corporation [Member] | Panola Pipeline Company, LLC [Member]
Noncontrolling Interest
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners (in hundredths)	15.00%
DCP Midstream Partners, LP [Member] | Panola Pipeline Company, LLC [Member]
Noncontrolling Interest
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners (in hundredths)	15.00%
MarkWest Energy Partners, L.P. [Member] | Panola Pipeline Company, LLC [Member]
Noncontrolling Interest
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners (in hundredths)	15.00%