Litigation And Other Contingencies (Schedule Of Unconditional Purchase Obligations) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Loss Contingencies [Line Items]
2012	$ 243	[1]
2013-2016	660	[1]
2017 and Beyond	410	[1]
Total	1,313	[1]
Present value of these commitments	1,084
Undiscounted unconditional purchase obligations	1,313
Imputed interest	229
Equity Company Obligations [Member]
Loss Contingencies [Line Items]
Undiscounted unconditional purchase obligations	$ 856

[1] Undiscounted obligations of $1,313 million mainly pertain to pipeline throughput agreements and include $856 million of obligations to equity companies. The present value of these commitments, which excludes imputed interest of $229 million, totaled $1,084 million.