Derivative Financial Instruments (Schedule Of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivative [Line Items]
Derivative Assets, Current	$ 128	$ 76
Derivative Assets, Noncurrent	57	91
Derivative Liabilities, Current	1	12
Derivative Liabilities, Noncurrent	0	10
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Net	185	167
Derivative Liability, Fair Value, Net	1	22
Not Designated as Hedging Instrument [Member] | Commodity Price Derivatives [Member] | Derivatives - Current [Member]
Derivative [Line Items]
Total derivatives, Asset, Gross	132	73
Total derivatives, Liability. Gross	5	19
Derivative Assets Offset In Balance Sheet	(4)	(7)
Derivative Liabilities Offset In Balance Sheet	(4)	(7)
Derivative Assets, Current	128	66
Derivative Liabilities, Current	1	12
Not Designated as Hedging Instrument [Member] | Commodity Price Derivatives [Member] | Derivatives - Noncurrent [Member]
Derivative [Line Items]
Total derivatives, Asset, Gross	62	95
Total derivatives, Liability. Gross	5	4
Derivative Assets Offset In Balance Sheet	(5)	(4)
Derivative Liabilities Offset In Balance Sheet	(5)	(4)
Derivative Assets, Noncurrent	57	91
Derivative Liabilities, Noncurrent	0	0
Not Designated as Hedging Instrument [Member] | Interest Rate Derivatives [Member] | Derivatives - Current [Member]
Derivative [Line Items]
Total derivatives, Asset, Gross		10
Derivative Assets Offset In Balance Sheet		0
Derivative Assets, Current		10
Not Designated as Hedging Instrument [Member] | Interest Rate Derivatives [Member] | Derivatives - Noncurrent [Member]
Derivative [Line Items]
Total derivatives, Asset, Gross		15
Total derivatives, Liability. Gross		25
Derivative Assets Offset In Balance Sheet		(15)
Derivative Liabilities Offset In Balance Sheet		(15)
Derivative Assets, Noncurrent		0
Derivative Liabilities, Noncurrent		$ 10