Intangible Assets and Goodwill Gross Carrying Amount of Intangibles and Goodwill (Details) - USD ($) $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
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| Gross Carrying Amount [Roll Forward] | ||||
| Balance at January 1 | $ 1,782 | $ 1,516 | ||
| Acquisitions | [1] | 1,701 | 384 | |
| Foreign currency translation and other | (81) | (118) | ||
| Balance at December 31 | $ 3,402 | $ 1,782 | ||
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