Other Expense (Schedule Of Components Of Other Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Expense [Abstract]
Transportation commitment charges	$ 43	$ 25	$ 82	$ 50
Third-party vertical integration services	5	16	11	29
Above market and idle drilling and well services equipment charges	0	11	0	47
Other	11	15	26	28
Total other expense	59	67	119	154
GrossRevenuesIncludedInThirdPartyLossFromVerticalIntegrationServices	23	56	42	124
GrossExpensesIncludedInThirdPartyLossFromVerticalIntegrationServices	$ 28	$ 72	$ 53	$ 153