Employee Benefit Obligations - Change in benefit accounts (Details) - Defined Benefit Pension Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in projected benefit obligation:
Benefit obligation at prior year end	$ 6,231	$ 6,197
Service cost	96	77	$ 61
Interest cost	86	128	173
Benefits paid	(293)	(426)
Net actuarial (gain) loss	(214)	514
Settlements and other	(362)	(392)
Plan amendments		6
Other	2	2
Effect of exchange rates	(53)	125
Benefit obligation at year end	5,493	6,231	6,197
Change in plan assets:
Fair value of plan assets at prior year end	5,838	5,716
Actual return on plan assets	147	682
Employer contributions	192	79
Contributions to unfunded plans	24	24
Benefits paid	(293)	(426)
Settlements and other	(380)	(359)
Other	2	1
Effect of exchange rates	(40)	121
Fair value of plan assets at end of year	5,490	5,838	5,716
Funded status	(3)	(393)
United States
Change in projected benefit obligation:
Benefit obligation at prior year end	2,752	2,849
Service cost	83	64	50
Interest cost	50	72	101
Benefits paid	(143)	(163)
Net actuarial (gain) loss	(76)	320
Settlements and other	(362)	(392)
Plan amendments		1
Other		1
Benefit obligation at year end	2,304	2,752	2,849
Change in plan assets:
Fair value of plan assets at prior year end	2,085	2,202
Actual return on plan assets	205	322
Employer contributions	187	77
Contributions to unfunded plans	6	6
Benefits paid	(143)	(163)
Settlements and other	(380)	(359)
Fair value of plan assets at end of year	1,960	2,085	2,202
Funded status	(344)	(667)
Accumulated benefit obligation	2,171	2,643
Non U.S.
Change in projected benefit obligation:
Benefit obligation at prior year end	3,479	3,348
Service cost	13	13	11
Interest cost	36	56	72
Benefits paid	(150)	(263)
Net actuarial (gain) loss	(138)	194
Plan amendments		5
Other	2	1
Effect of exchange rates	(53)	125
Benefit obligation at year end	3,189	3,479	3,348
Change in plan assets:
Fair value of plan assets at prior year end	3,753	3,514
Actual return on plan assets	(58)	360
Employer contributions	5	2
Contributions to unfunded plans	18	18
Benefits paid	(150)	(263)
Other	2	1
Effect of exchange rates	(40)	121
Fair value of plan assets at end of year	3,530	3,753	$ 3,514
Funded status	341	274
Accumulated benefit obligation	$ 3,185	$ 3,476