Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
PRB plans	$ 4	$ 5
Defined contribution plans	372	311
Liability, Defined Benefit Plan, Current	307		$ 307
Liability, Defined Benefit Pension Plan, Noncurrent	4,676		4,807
Non-service pension income	(444)	(480)
Total net periodic benefit (income) expense	(388)	(360)
Marketable securities held in trusts	703		774
UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plans	0	0
Foreign Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plans	8	12
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	3,527		3,301
Liability, Defined Benefit Pension Plan, Noncurrent	4,004		4,133
Service cost	55	118
Interest cost	626	382
Expected return on plan assets	(937)	(890)
Amortization of prior service credit	(39)	(42)
Recognized actuarial net loss (gain)	(95)	77
Net settlement, curtailment and special termination benefit (gain) loss	2	(6)
Non-service pension income	(443)	(479)
Total net periodic benefit (income) expense	(388)	(361)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Liability, Defined Benefit Pension Plan, Noncurrent	612		611
Service cost	1	2
Interest cost	12	7
Expected return on plan assets	(5)	(5)
Amortization of prior service credit	0	0
Recognized actuarial net loss (gain)	(8)	(3)
Net settlement, curtailment and special termination benefit (gain) loss	0	0
Non-service pension income	(1)	(1)
Total net periodic benefit (income) expense	0	$ 1
Other pension and PRB related items
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Liability, Defined Benefit Pension Plan, Noncurrent	$ 60		$ 63