v3.21.1
Changes in Equity (Details) - USD ($)
 3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Beginning Balance $ 29,849,000,000 $ 35,050,000,000
Net income (loss) 982,000,000 (1,711,000,000)
Other Comprehensive Income (Loss), Net of Tax 138,000,000 (788,000,000)
Dividends paid (588,000,000) (458,000,000)
Acquisition of Concho 13,125,000,000  
Repurchase of company common stock (375,000,000) (726,000,000)
Distributions to noncontrolling interests   (26,000,000)
Distributed under benefit plans 23,000,000 44,000,000
Other 1,000,000 2,000,000
Ending Balance 43,155,000,000 31,387,000,000
Par Value - Common Stock [Member]    
Beginning Balance 18,000,000 18,000,000
Acquisition of Concho 3,000,000  
Ending Balance 21,000,000 18,000,000
Capital in excess of par [Member]    
Beginning Balance 47,133,000,000 46,983,000,000
Acquisition of Concho 13,122,000,000  
Distributed under benefit plans 23,000,000 44,000,000
Ending Balance 60,278,000,000 47,027,000,000
Treasury Stock [Member]    
Beginning Balance (47,297,000,000) (46,405,000,000)
Repurchase of company common stock (375,000,000) (726,000,000)
Other   1,000,000
Ending Balance (47,672,000,000) (47,130,000,000)
Accumulated Other Comprehensive Income (Loss) [Member]    
Beginning Balance (5,218,000,000) (5,357,000,000)
Other Comprehensive Income (Loss), Net of Tax 138,000,000 (788,000,000)
Ending Balance (5,080,000,000) (6,145,000,000)
Retained Earnings [Member]    
Beginning Balance 35,213,000,000 39,742,000,000
Net income (loss) 982,000,000 (1,739,000,000)
Dividends paid (588,000,000) (458,000,000)
Other 1,000,000  
Ending Balance $ 35,608,000,000 37,545,000,000
Noncontrolling Interest [Member]    
Beginning Balance   69,000,000
Net income (loss)   28,000,000
Distributions to noncontrolling interests   (26,000,000)
Other   1,000,000
Ending Balance   $ 72,000,000