Commitments - Undiscounted Gathering Processing and Transportation Agreements Commitments Table (Details) (Gas Gathering and Processing Equipment [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2014
Gas Gathering and Processing Equipment [Member]
Other Commitments [Line Items]
Other Commitment, Due in Next Twelve Months	$ 1,546
Other Commitment, Due in Second Year	1,830
Other Commitment, Due in Third Year	1,915
Other Commitment, Due in Fourth Year	1,948
Other Commitment, Due in Fifth Year	1,749
Other Commitment, Due after Fifth Year	7,746
Other Commitment	$ 16,734