Segment Disclosures and Related Information - Assets (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Assets [Abstract]
Total Assets	$ 87,304	$ 62,618
Alaska [Member] \| Operating Segments [Member]
Assets [Abstract]
Total Assets	14,617	14,623
Lower 48 [Member] \| Operating Segments [Member]
Assets [Abstract]
Total Assets	33,200	11,932
Canada [Member] \| Operating Segments [Member]
Assets [Abstract]
Total Assets	6,797	6,863
Europe, Middle East and North Africa [Member] \| Operating Segments [Member]
Assets [Abstract]
Total Assets	8,956	8,756
Asia Pacific [Member] \| Operating Segments [Member]
Assets [Abstract]
Total Assets	10,657	11,231
Other International [Member] \| Operating Segments [Member]
Assets [Abstract]
Total Assets	1	226
Corporate and Other [Member] \| Corporate, Non-Segment [Member]
Assets [Abstract]
Total Assets	$ 13,076	$ 8,987

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Name:	us-gaap_Assets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant