Supplemental Financial Information - Post-employment obligations and other long-term liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Post-employment Obligations and Other Long-term Liabilities:
Defined benefit pension plans and post-employment medical and dental plans for significant plans	$ 2,738	$ 3,119
Deferred income taxes	1,392	1,406
Operating lease liabilities	956	902
All other	3,685	3,684
Total	8,771	9,111
All other disclosures
Net unrecognized tax benefits	1,908	1,210	$ 1,175
Post-employment Obligations and Other Long-term Liabilities:
All other disclosures
Net unrecognized tax benefits	$ 680	$ 740