Fair Value Measurements (Details) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)
Oil and Gas segment
Liabilities:
Impairment and related charges	$ 285	$ 285
ISSD
Liabilities:
Impairment and related charges	40	41
Qatar ISND and ISSD
Liabilities:
Impairment and related charges			$ 416
Total Fair Value
Liabilities:
Estimated fair value of debt	47,800	47,800	10,300
Total Fair Value | WES Midstream
Liabilities:
Estimated fair value of debt	7,600	7,600
Level 2 | Total Fair Value
Liabilities:
Estimated fair value of debt	12,500	12,500
Recurring | Accrued liabilities
Liabilities:
Netting and Collateral	0	0	0
Recurring | Accrued liabilities | Total Fair Value
Liabilities:
Embedded derivatives	54	54	66
Recurring | Accrued liabilities | Level 1
Liabilities:
Embedded derivatives	0	0	0
Recurring | Accrued liabilities | Level 2
Liabilities:
Embedded derivatives	54	54	66
Recurring | Accrued liabilities | Level 3
Liabilities:
Embedded derivatives	0	0	0
Recurring | Deferred credits and other liabilities - other
Liabilities:
Netting and Collateral	0	0	0
Recurring | Deferred credits and other liabilities - other | Total Fair Value
Liabilities:
Embedded derivatives	73	73	116
Recurring | Deferred credits and other liabilities - other | Level 1
Liabilities:
Embedded derivatives	0	0	0
Recurring | Deferred credits and other liabilities - other | Level 2
Liabilities:
Embedded derivatives	73	73	116
Recurring | Deferred credits and other liabilities - other | Level 3
Liabilities:
Embedded derivatives	$ 0	$ 0	$ 0
Non recurring | Measurement Input, Discount Rate
Liabilities:
Risk adjusted discount rate			0.10