Segment Disclosures and Related Information - Net Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	$ (1,739)	$ 1,833
Assets [Abstract]
Assets	65,033		$ 70,514
Alaska [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	81	384
Assets [Abstract]
Assets	15,603		15,453
Lower 48 [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	(437)	193
Assets [Abstract]
Assets	12,717		14,425
Canada [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	(109)	122
Assets [Abstract]
Assets	5,682		6,350
Europe and North Africa [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	75	207
Assets [Abstract]
Assets	7,056		8,121
Asia Pacific and Middle East [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	398	525
Assets [Abstract]
Assets	14,337		14,716
Other International [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	28	131
Assets [Abstract]
Assets	289		285
Corporate and Other [Member] \| Corporate, Non-Segment [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	(1,775)	$ 271
Assets [Abstract]
Assets	$ 9,349		$ 11,164