Postemployment benefit plans (Details A2) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
U.S. pensions
Pension plans with projected benefit obligation in excess of plan assets
Projected benefit obligation	$ 14,403	$ 15,300
Fair value of plan assets	13,143	13,302
Pension plans with accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation	14,403	15,300
Fair value of plan assets	13,143	13,302
Non-U.S. pensions
Pension plans with projected benefit obligation in excess of plan assets
Projected benefit obligation	743	2,171
Fair value of plan assets	319	1,499
Pension plans with accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation	603	1,988
Fair value of plan assets	$ 234	$ 1,425