Discontinued Operations (Consolidated Comprehensive Statement of Earnings as Discontinued Operations) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Discontinued Operations And Disposal Groups [Abstract]
Marketing and midstream revenues	$ 1,595	$ 1,094	$ 3,207	$ 2,245
Marketing and midstream expenses	1,269	865	2,610	1,800
Depreciation, depletion and amortization	106	137	244	265
General and administrative expenses	31	31	58	67
Financing costs, net	45	39	89	84
Other expenses	(5)	(15)	(7)	(20)
Total expenses	1,446	1,057	2,994	2,196
Earnings from discontinued operations before income taxes	149	37	213	49
Income tax expense	10	4	16	7
Net earnings from discontinued operations, net of income tax expense	139	33	197	42
Net earnings attributable to noncontrolling interests	90	26	134	40
Net earnings from discontinued operations attributable to Devon	$ 49	$ 7	$ 63	$ 2