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Proposed Separation Transaction - Narrative (Details) $ in Millions |  | 3 Months Ended | 9 Months Ended
--- | --- | --- | ---
Feb. 08, 2019 company | Sep. 30, 2019 USD ($) | Sep. 30, 2018 USD ($) | Sep. 30, 2019 USD ($) | Sep. 30, 2018 USD ($)
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Number of independent, publicly-traded companies resulting from proposed separation transaction | company | 2 |  |  |  |
Restructuring and other charges (D) |  | $ 119 | $ (2) | $ 630 | $ 20
Business separation | Proposed Separation Transaction | Selling, General and Administrative Expenses |  |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |  |
Restructuring and other charges (D) |  | $ 25 |  | $ 44 |

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