Fair Value Measurements (Schedule Of Carrying Value And Fair Value Measurement Information For Financial Assets And Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	$ 1,717	$ 2,004
Derivatives, liabilities	(58)	(57)
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,321	950
Debt	(11,749)	(11,262)
Capital lease obligations	(19)	(20)
Total Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,321	950
Debt	(13,217)	(12,472)
Capital lease obligations	(19)	(20)
Level 1 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	716	340
Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	605	610
Debt	(13,217)	(12,472)
Capital lease obligations	(19)	(20)
Oil, Gas And NGL Commodity Derivatives [Member] | Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	1,670	1,968
Derivatives, liabilities	(52)	(51)
Oil, Gas And NGL Commodity Derivatives [Member] | Total Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	1,670	1,968
Derivatives, liabilities	(52)	(51)
Oil, Gas And NGL Commodity Derivatives [Member] | Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	1,670	1,968
Derivatives, liabilities	(52)	(51)
Midstream Commodity Derivatives [Member] | Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	22	27
Derivatives, liabilities	(5)	(5)
Midstream Commodity Derivatives [Member] | Total Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	22	27
Derivatives, liabilities	(5)	(5)
Midstream Commodity Derivatives [Member] | Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	22	27
Derivatives, liabilities	(5)	(5)
Interest Rate Derivatives [Member] | Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	3	1
Derivatives, liabilities	(1)	(1)
Interest Rate Derivatives [Member] | Total Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	3	1
Derivatives, liabilities	(1)	(1)
Interest Rate Derivatives [Member] | Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	3	1
Derivatives, liabilities	(1)	(1)
Foreign Currency Derivatives [Member] | Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	22	8
Foreign Currency Derivatives [Member] | Total Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	22	8
Foreign Currency Derivatives [Member] | Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, assets	$ 22	$ 8