Employee Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
PRB plans	$ 4	$ 4	$ 9	$ 4
Defined contribution plans	251	238	562	509
Liability, Defined Benefit Plan, Current	309		309		$ 310
Liability, Defined Benefit Pension Plan, Noncurrent	7,543		7,543		7,855
Non-service pension income	(474)	(490)	(954)	(981)
Total net periodic benefit (income) expense			(714)	(715)
Marketable securities held in trusts	788		788		965
Foreign Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plans	18	14	30	21
UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plans	0	0	0	0
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	3,869		3,869		3,214
Liability, Defined Benefit Pension Plan, Noncurrent	6,596		6,596		6,873
Service cost	118	131	236	262
Interest cost	380	313	762	625
Expected return on plan assets	(888)	(871)	(1,778)	(1,739)
Amortization of prior service credit	(41)	(42)	(83)	(84)
Recognized actuarial net loss (gain)	77	109	154	218
Net settlement, curtailment and special termination benefit (gain) loss	0	3	(6)	3
Non-service pension income	(472)	(488)	(951)	(977)
Total net periodic benefit (income) expense	(354)	(357)	(715)	(715)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Liability, Defined Benefit Pension Plan, Noncurrent	876		876		903
Service cost	2	2	4	4
Interest cost	7	6	14	12
Expected return on plan assets	(6)	(5)	(11)	(10)
Amortization of prior service credit	0	(1)	0	(2)
Recognized actuarial net loss (gain)	(3)	(2)	(6)	(4)
Net settlement, curtailment and special termination benefit (gain) loss	0	0	0	0
Non-service pension income	(2)	(2)	(3)	(4)
Total net periodic benefit (income) expense	0	$ 0	1	$ 0
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	$ 71		$ 71		$ 79