Consolidated Statements of Cash Flows (Unaudited) $ in Millions	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Statement of Cash Flows [Abstract]
Net income	$ 500	$ 706
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	1,781	1,828
Impairments	24	50
Exploratory dry well costs and unproved property impairments	85	144
Net gain on disposal of assets	(56)	(323)
Deferred income taxes	(34)	62
Net loss on derivative instruments	28	324
Net settlements of derivative instruments	41	(255)
Pension and other post retirement benefits, net	(51)	(60)
Stock-based compensation	45	44
Equity method investments, net	26	42
Changes in:
Current receivables	(99)	(389)
Inventories	4	(11)
Current accounts payable and accrued liabilities	(164)	334
Other current assets and liabilities	108	0
All other operating, net	(189)	(117)
Net Cash Provided by (Used in) Operating Activities	2,049	2,379
Investing activities:
Additions to property, plant and equipment	(1,934)	(2,069)
Additions to other assets	41	(135)
Acquisitions, net of cash acquired	0	(25)
Disposal of assets, net of cash transferred to the buyer	(84)	1,249
Equity method investments - return of capital	51	48
All other investing, net	2	11
Net cash used in investing activities	(1,924)	(921)
Financing activities:
Purchases of common stock	(296)	(349)
Dividends paid	(122)	(128)
All other financing, net	(4)	22
Net cash used in financing activities	(422)	(455)
Effect of exchange rate on cash and cash equivalents	0	(2)
Net increase (decrease) in cash and cash equivalents	(297)	1,001
Cash and cash equivalents at beginning of period		$ 563
Cash and cash equivalents at end of period	1,165
Cash and cash equivalents	$ 1,165