Postemployment benefit plans (Details C) $ in Millions	Dec. 31, 2021 USD ($)
U.S. pensions
Expected contributions and benefit payments for pension and other postretirement benefit plans
Employer contribution expected for 2022	$ 46
Expected benefit payments for 2022	1,035
Expected benefit payments for 2023	1,020
Expected benefit payments for 2024	1,020
Expected benefit payments for 2025	1,020
Expected benefit payments for 2026	1,020
Expected benefit payments from 2027-2031	4,960
Total expected benefit payments	10,075
Non-U.S. pensions
Expected contributions and benefit payments for pension and other postretirement benefit plans
Employer contribution expected for 2022	55
Expected benefit payments for 2022	210
Expected benefit payments for 2023	175
Expected benefit payments for 2024	180
Expected benefit payments for 2025	185
Expected benefit payments for 2026	195
Expected benefit payments from 2027-2031	1,045
Total expected benefit payments	1,990
Other postretirement benefits
Expected contributions and benefit payments for pension and other postretirement benefit plans
Employer contribution expected for 2022	256
Expected benefit payments for 2022	275
Expected benefit payments for 2023	270
Expected benefit payments for 2024	265
Expected benefit payments for 2025	260
Expected benefit payments for 2026	260
Expected benefit payments from 2027-2031	1,250
Total expected benefit payments	2,580
Other postretirement benefits, Medicare Part D subsidy expected
Other postretirement benefits, Medicare Part D subsidy expected in 2022	7
Other postretirement benefits, Medicare Part D subsidy expected in 2023	7
Other postretirement benefits, Medicare Part D subsidy expected in 2024	7
Other postretirement benefits, Medicare Part D subsidy expected in 2025	7
Other postretirement benefits, Medicare Part D subsidy expected in 2026	6
Other postretirement benefits, Medicare Part D subsidy expected from 2027-2031	26
Total expected Medicare D subsidy receipts	$ 60