Postemployment benefit plans (Details 3) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
U.S. pensions
Pension plans with projected benefit obligations in excess of plan assets
Projected Benefit Obligations	$ 14,037	$ 15,614
Accumulated benefit obligation	14,037	15,541
Fair value of plant assets	12,039	12,349
Pension plans with accumulated benefit obligations in excess of plan assets
Projected benefit obligation	14,037	15,614
Accumulated benefit obligation	14,037	15,541
Fair value of plan assets	12,039	12,349
Non-U.S. pensions
Pension plans with projected benefit obligations in excess of plan assets
Projected Benefit Obligations	2,010	1,821
Accumulated benefit obligation	1,896	1,723
Fair value of plant assets	1,384	1,189
Pension plans with accumulated benefit obligations in excess of plan assets
Projected benefit obligation	1,875	1,655
Accumulated benefit obligation	1,799	1,603
Fair value of plan assets	$ 1,269	$ 1,047

Amount of accumulated benefit obligation for defined benefit pension plan with projected benefit obligation in excess of plan assets.

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Amount of plan asset for defined benefit pension plan with projected benefit obligation in excess of plan assets.

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Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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