Derivative Instruments Schedule Of Derivative Assets And Liabilities (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Derivative Asset, Fair Value, Gross Asset	$ 7	$ 5
Derivative Liability, Fair Value, Gross Liability	28	31
Derivatives Designated as Cash Flow Hedges [Member] | Commodity Derivatives
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	0	5
Current | Derivatives Designated as Cash Flow Hedges [Member] | Commodity Derivatives
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	0	5
Current | Derivatives Not Designated as Cash Flow Hedges [Member] | Commodity Derivatives
Derivative Asset, Fair Value, Gross Asset	6	4
Derivative Liability, Fair Value, Gross Liability	5	1
Long Term | Derivatives Not Designated as Cash Flow Hedges [Member] | Commodity Derivatives
Derivative Asset, Fair Value, Gross Asset	1	1
Derivative Liability, Fair Value, Gross Liability	0	0
Long Term | Derivatives Not Designated as Cash Flow Hedges [Member] | Embedded Derivatives in Series A Preferred Units [Member]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	$ 23	$ 25