Pension and Postretirement Benefit Plans and Defined Contribution Plans - Funded Status Recognized in Consolidated Balance Sheets (Details) - USD ($) $ in Millions |
Dec. 31, 2018 |
Dec. 31, 2017 |
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|---|---|---|---|---|---|---|---|---|---|
| Postretirement Benefits Plan [Member] | |||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||
| Noncurrent assets | [1] | $ 0 | $ 0 | ||||||
| Current liabilities | [2] | (29) | (31) | ||||||
| Noncurrent liabilities | [3] | (1,371) | (1,504) | ||||||
| Funded status | (1,401) | (1,534) | |||||||
| United States [Member] | Pension Plan [Member] | |||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||
| Noncurrent assets | [1] | 0 | 0 | ||||||
| Current liabilities | [2] | (1) | 0 | ||||||
| Noncurrent liabilities | [3] | (2,088) | (2,418) | ||||||
| Funded status | (2,089) | (2,418) | |||||||
| United States [Member] | U.S. Supplemental (Non-Qualified) Pension Plans [Member] | |||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||
| Noncurrent assets | [1] | 0 | 0 | ||||||
| Current liabilities | [2] | (167) | (160) | ||||||
| Noncurrent liabilities | [3] | (1,113) | (1,336) | ||||||
| Funded status | (1,280) | (1,495) | |||||||
| Foreign Plan [Member] | Pension Plan [Member] | |||||||||
| Defined Benefit Plan Disclosure [Line Items] | |||||||||
| Noncurrent assets | [1] | 401 | 454 | ||||||
| Current liabilities | [2] | (28) | (26) | ||||||
| Noncurrent liabilities | [3] | (2,111) | (2,172) | ||||||
| Funded status | $ (1,738) | $ (1,745) | |||||||
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