Restructuring Charges/Other - Components of Restructuring Charges and Other (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
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| Restructuring And Related Activities [Abstract] | |||||||||||||
| Restructuring charges | [1] | $ 25 | $ 14 | $ 20 | |||||||||
| Gains on sales of assets | (40) | (83) | (75) | ||||||||||
| Other | 0 | (2) | 4 | ||||||||||
| Restructuring charges/other | $ (20) | $ 1 | $ 2 | $ 2 | $ (68) | $ 0 | $ (1) | $ (2) | $ (15) | $ (71) | $ (51) | ||
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