Segment Disclosures and Related Information - Net Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	$ 260	$ 1,580	$ (1,479)	$ 3,413
Assets [Abstract]
Assets	63,046		63,046		$ 70,514
Alaska [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	(141)	462	(60)	846
Assets [Abstract]
Assets	16,121		16,121		15,453
Lower 48 [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	(365)	206	(802)	399
Assets [Abstract]
Assets	12,158		12,158		14,425
Canada [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	(86)	100	(195)	222
Assets [Abstract]
Assets	5,909		5,909		6,350
Europe and North Africa [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	11	407	86	614
Assets [Abstract]
Assets	7,204		7,204		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	662	517	1,060	1,042
Assets [Abstract]
Assets	12,404		12,404		14,716
Other International [Member] \| Operating Segments [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	(6)	81	22	212
Assets [Abstract]
Assets	299		299		285
Corporate and Other [Member] \| Corporate, Non-Segment [Member]
Net Income (Loss) Attributable to ConocoPhillips [Abstract]
Consolidated net income (loss) attributable to ConocoPhillips	185	$ (193)	(1,590)	$ 78
Assets [Abstract]
Assets	$ 8,951		$ 8,951		$ 11,164