Commitments And Contingencies (Narrative) (Details)		1 Months Ended	12 Months Ended
	Nov. 17, 2015 item	Sep. 30, 2015 plaintiff item	Dec. 31, 2016 USD ($) item	Dec. 31, 2010 USD ($)
Commitments And Contingencies [Line Items]
Total future demand transportation charges due			$ 8,400,000,000
Obligation under transportation agreements			8,429,000,000
Guarantee obligations relative to the firms transportation agreements and gathering project and services			$ 862,000,000
Lease expiration date			Dec. 31, 2027
Residual value guarantee liability			$ 4,000,000
Operating leases, future minimum payments, 2017			66,000,000
Operating leases, future minimum payments, 2018			52,000,000
Operating leases, future minimum payments, 2019			45,000,000
Operating leases, future minimum payments, 2020			35,000,000
Operating leases, future minimum payments, 2021			17,000,000
Operating leases, future minimum payments, thereafter			14,000,000
Actual damages recoverable by plaintiff				$ 11,000,000
Disgorgement recoverable by plaintiff				$ 24,000,000
Indemnification liability			0
Purchase Commitment [Member] | Access Capacity on Future Projects Concentration Risk [Member]
Commitments And Contingencies [Line Items]
Obligation under transportation agreements			$ 3,400,000,000
Arkansas Royalty Litigation [Member]
Commitments And Contingencies [Line Items]
Number of cases | item			3
Arkansas Royalty Litigation [Member] | Arkansas State Court 2010 and 2013 [Member]
Commitments And Contingencies [Line Items]
Number of cases | item			2
Arkansas Royalty Litigation [Member] | Federal Court 2014 [Member]
Commitments And Contingencies [Line Items]
Number of cases | item			1
Number of alternative damages theories presented | item	2
Loss contingency, range of possible loss, minimum			$ 100,000,000
Arkansas Royalty Litigation [Member] | Arkansas State Court 2015 [Member]
Commitments And Contingencies [Line Items]
Number of cases | item		3
Number of plaintiffs | plaintiff		248
Pending Regulatory Approval and/or Construction [Member]
Commitments And Contingencies [Line Items]
Obligation under transportation agreements			$ 3,362,000,000
Exploration and Production [Member] | Pressure Pumping Equipment [Member]
Commitments And Contingencies [Line Items]
Number of leases | item			13
Aggregate annual lease payment			$ 8,000,000
Exploration and Production [Member] | Drilling Rigs [Member]
Commitments And Contingencies [Line Items]
Number of leases | item			7
Lease expiration date			Dec. 31, 2021
Aggregate annual lease payment			$ 13,000,000
Exploration and Production [Member] | Maximum [Member] | Pressure Pumping Equipment [Member]
Commitments And Contingencies [Line Items]
Lease expiration date			Jan. 01, 2018
Exploration and Production [Member] | Minimum [Member] | Pressure Pumping Equipment [Member]
Commitments And Contingencies [Line Items]
Lease expiration date			Dec. 01, 2017
Midstream Services and E&P [Member]
Commitments And Contingencies [Line Items]
Operating leases, future minimum payments, 2017			$ 16,000,000
Operating leases, future minimum payments, 2018			7,000,000
Operating leases, future minimum payments, 2019			$ 3,000,000