Supplemental Information To Statements Of Cash Flows (Schedule Of Supplemental To Cash Flow Information) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net change in working capital accounts:
Accounts receivable	$ (288)	$ 140	$ (185)
Other current assets	49	(128)	125
Accounts payable	26	(8)	64
Revenues and royalties payable	35	19	144
Other current liabilities	(120)	(73)	32
Net change in working capital	(298)	(50)	180
Interest paid (net of capitalized interest)	406	334	325
Income taxes paid (received)	$ 13	$ 100	$ (383)