(Goodwill) (Details) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($)
Finite-Lived Intangible Assets [Line Items]
Impairment	$ 1,197
Income Approach \| Discount Rate \| Minimum
Finite-Lived Intangible Assets [Line Items]
Fair value inputs	9.00%
Income Approach \| Discount Rate \| Maximum
Finite-Lived Intangible Assets [Line Items]
Fair value inputs	10.00%
Midstream
Finite-Lived Intangible Assets [Line Items]
Impairment	$ 1,197
Midstream \| Prior to change in reporting units
Finite-Lived Intangible Assets [Line Items]
Impairment	1,156
Midstream \| Subsequent to change in reporting units
Finite-Lived Intangible Assets [Line Items]
Impairment	$ 41

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13854-109267

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13777-109266

Name:	us-gaap_GoodwillImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration