Segment Information (Condensed Statements Of Comprehensive Earnings And Balance Sheets Of Reportable Segments) (Details) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) segment	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Revenues from external customers		$ 2,249	$ 2,165	$ 4,447	$ 4,565
Depreciation, depletion and amortization		420	369	819	769
Interest expense		69	81	464	166
Asset impairments		154		154
Asset dispositions		23	(22)	11	(30)
Restructuring and transaction costs		94		94
Earnings (loss) from continuing operations before income taxes		(481)	207	(726)	520
Income tax expense (benefit)		(7)	(5)	(41)
Net earnings (loss) from continuing operations		(474)	212	(685)	520
Capital expenditures, including acquisitions		645	456	1,346	884
Property and equipment, net		14,121	14,217	14,121	14,217	$ 14,584
Total continuing assets		29,159		29,159		$ 30,241
Continuing Operations [Member]
Segment Reporting Information [Line Items]
Total continuing assets	[1]	18,395	18,927	$ 18,395	18,927
United States [Member]
Segment Reporting Information [Line Items]
Number of reportable segments | segment				1
United States [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers		1,922	1,891	$ 3,801	3,972
Depreciation, depletion and amortization		342	283	647	585
Interest expense		72	81	319	161
Asset impairments		154		154
Asset dispositions		23	(22)	11	(29)
Restructuring and transaction costs		85		85
Earnings (loss) from continuing operations before income taxes		(471)	213	(587)	523
Income tax expense (benefit)		13	2	14	5
Net earnings (loss) from continuing operations		(484)	211	(601)	518
Capital expenditures, including acquisitions		585	385	1,197	731
Property and equipment, net		10,031	10,051	10,031	10,051
United States [Member] | Operating Segments [Member] | Continuing Operations [Member]
Segment Reporting Information [Line Items]
Total continuing assets	[1]	13,247	13,907	13,247	13,907
Canada [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers		327	274	646	593
Depreciation, depletion and amortization		78	86	172	184
Interest expense		(3)		145	5
Asset dispositions					(1)
Restructuring and transaction costs		9		9
Earnings (loss) from continuing operations before income taxes		(10)	(6)	(139)	(3)
Income tax expense (benefit)		(20)	(7)	(55)	(5)
Net earnings (loss) from continuing operations		10	1	(84)	2
Capital expenditures, including acquisitions		60	71	149	153
Property and equipment, net		4,090	4,166	4,090	4,166
Canada [Member] | Operating Segments [Member] | Continuing Operations [Member]
Segment Reporting Information [Line Items]
Total continuing assets	[1]	$ 5,148	$ 5,020	$ 5,148	$ 5,020

[1] Total assets in the table above do not include assets held for sale related to Devon’s discontinued operations, which totaled $10.8 billion and $10.2 billion on June 30, 2018 and June 30, 2017, respectively.