Organization And Summary Of Significant Accounting Policies (Narrative) (Details) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended			12 Months Ended
	Dec. 19, 2014 USD ($)	Jan. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) $ / shares $ / bbl $ / MMBTU shares	Dec. 31, 2014 USD ($) $ / bbl $ / MMBTU shares	Dec. 31, 2013 $ / bbl $ / MMBTU	Feb. 28, 2015 $ / shares
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Outstanding checks included in accounts payable			$ 29			$ 29	$ 17
Inventory write-down of carrying value			23			$ 23
Natural gas, oil and NGL reserves discount						10.00%	10.00%	10.00%
Period of time needed to calculate ceiling value of reserves						12 months	12 months	12 months
Net capitalized costs exceeding ceiling			$ 1,586	$ 1,746	$ 944
Cash flow hedges impact on ceiling value, net of tax				$ 40	$ 60
Amount recognized is the largest amount of tax benefit, threshold						50.00%
Number of common shares: Effect of issuance of non-vested performance units | shares							273,918
Treasury stock, shares | shares			47,149			47,149	11,055
Net long term deferred income tax liability							$ 1,951
Net current deferred income tax liability							109
Senior Notes [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Proceeds from issuance of debt		$ 2,200				$ 2,200
Bridge Loan [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Bridge loan	$ 4,500						$ 4,500
Debt instrument, term	364 days						364 days
NGL [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Full cost ceiling test, price | $ / bbl						6.82	23.79	43.45
Henry Hub Natural Gas [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Full cost ceiling test, price | $ / MMBTU						2.59	4.35	3.67
West Texas Intermediate Oil [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Full cost ceiling test, price | $ / bbl						46.79	91.48	93.42
Gathering Systems [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Straight-line depreciation period						25 years
Common Stock [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Shares issued | shares		30,000,000
Share price | $ / shares		$ 23.00
Proceeds from issuance of shares		$ 669
Depositary Shares [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Shares issued | shares		34,500,000
Proceeds from issuance of shares		$ 1,700
Depositary shares conversion rate		0.05
Liquidation preference per share | $ / shares		$ 50
Series B Preferred Stock [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Liquidation preference per share | $ / shares			$ 1,000			$ 1,000			$ 1,000
Trading day period						20 days
Minimum [Member] | Depositary Shares [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Shares issued upon conversion | shares			1.85014			1.85014
Minimum [Member] | Series B Preferred Stock [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Shares issued upon conversion | shares			37.0028			37.0028
Maximum [Member] | Depositary Shares [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Shares issued upon conversion | shares			2.17391			2.17391
Maximum [Member] | Series B Preferred Stock [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Shares issued upon conversion | shares			43.4782			43.4782
WPX Property Acquisition [Member]
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Percentage of interest acquired			86.00%			86.00%