Equity (Changes in Shares of Common Stock) (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Beginning of year	1,798,844,267	1,795,652,203	1,791,637,434
Acquisition of Concho	285,928,872	0	0
Distributed under benefit plans	6,789,608	3,192,064	4,014,769
End of year	2,091,562,747	1,798,844,267	1,795,652,203
Beginning of year	730,802,089	710,783,814	653,288,213
Repurchase of common stock	58,517,786	20,018,275	57,495,601
End of year	789,319,875	730,802,089	710,783,814