Pension, Other Postretirement Benefits and Savings Plans - Selected Pension Plan Information (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
United States
All plans:
Accumulated benefit obligation	$ 4,725	$ 5,320
Plans not fully-funded:
Projected benefit obligation	4,732	5,329
Accumulated benefit obligation	4,723	5,318
Fair value of plan assets	4,443	4,976
Non-U.S.
All plans:
Accumulated benefit obligation	2,688	3,017
Plans not fully-funded:
Projected benefit obligation	908	945
Accumulated benefit obligation	852	887
Fair value of plan assets	$ 281	$ 302

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Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

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

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

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