Postretirement Benefit Plans - Assumed Future Benefits Payments (Details) $ in Millions	Dec. 31, 2018 USD ($)
United States | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
2019 payment	$ 78
2020 payment	105
2021 payment	77
2022 payment	79
2023 payment	85
2024 - 2028 payment	428
United States | Retiree health care plan
Defined Benefit Plan Disclosure [Line Items]
2019 payment	32
2020 payment	31
2021 payment	30
2022 payment	29
2023 payment	28
2024 - 2028 payment	124
Non-U.S. | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
2019 payment	88
2020 payment	90
2021 payment	92
2022 payment	95
2023 payment	95
2024 - 2028 payment	$ 510