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Fair Value Measurements and Financial Instruments Schedule of assets and liabilities that are measured at fair value on a recurring basis (Details) - Recurring [Member] - USD ($) $ in Millions | Jun. 30, 2015 | Dec. 31, 2014
--- | --- | ---
Money market funds and highly liquid debt securities |  |  |  |
Assets: |  |  |  |
Money market funds and highly liquid debt securities | $ 1,895 | [1] | $ 1,850 | [2]
Money market funds [Member] |  |  |  |
Assets: |  |  |  |
Money market funds and highly liquid debt securities | 1,895 |  | 1,850 |
Corporate bonds [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 1 |  | 1 |
Government bonds [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 6 |  | 6 |
Equity investments [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 10 |  | 11 |
Interest rate contracts [Member] |  |  |  |
Assets: |  |  |  |
Derivatives | 0 |  | 0 |
Foreign exchange contracts [Member] |  |  |  |
Assets: |  |  |  |
Derivatives | 54 |  | 46 |
Liabilities: |  |  |  |
Derivatives | 57 |  | 58 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Money market funds and highly liquid debt securities |  |  |  |
Assets: |  |  |  |
Money market funds and highly liquid debt securities | 1,895 | [1] | 1,850 | [2]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate bonds [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 0 |  | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Government bonds [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 0 |  | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity investments [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 6 |  | 6 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Interest rate contracts [Member] |  |  |  |
Assets: |  |  |  |
Derivatives | 0 |  | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Foreign exchange contracts [Member] |  |  |  |
Assets: |  |  |  |
Derivatives | 0 |  | 0 |
Liabilities: |  |  |  |
Derivatives | 0 |  | 0 |
Significant Other Observable Inputs (Level 2) [Member] | Money market funds and highly liquid debt securities |  |  |  |
Assets: |  |  |  |
Money market funds and highly liquid debt securities | 0 | [1] | 0 | [2]
Significant Other Observable Inputs (Level 2) [Member] | Corporate bonds [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 0 |  | 0 |
Significant Other Observable Inputs (Level 2) [Member] | Government bonds [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 6 |  | 6 |
Significant Other Observable Inputs (Level 2) [Member] | Equity investments [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 4 |  | 5 |
Significant Other Observable Inputs (Level 2) [Member] | Interest rate contracts [Member] |  |  |  |
Assets: |  |  |  |
Derivatives | 0 |  | 0 |
Significant Other Observable Inputs (Level 2) [Member] | Foreign exchange contracts [Member] |  |  |  |
Assets: |  |  |  |
Derivatives | 54 |  | 46 |
Liabilities: |  |  |  |
Derivatives | 57 |  | 58 |
Significant Unobservable Inputs (Level 3) [Member] | Money market funds and highly liquid debt securities |  |  |  |
Assets: |  |  |  |
Money market funds and highly liquid debt securities | 0 | [1] | 0 | [2]
Significant Unobservable Inputs (Level 3) [Member] | Corporate bonds [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 1 |  | 1 |
Significant Unobservable Inputs (Level 3) [Member] | Government bonds [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 0 |  | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Equity investments [Member] |  |  |  |
Assets: |  |  |  |
Other investments | 0 |  | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Interest rate contracts [Member] |  |  |  |
Assets: |  |  |  |
Derivatives | 0 |  | 0 |
Significant Unobservable Inputs (Level 3) [Member] | Foreign exchange contracts [Member] |  |  |  |
Assets: |  |  |  |
Derivatives | 0 |  | 0 |
Liabilities: |  |  |  |
Derivatives | $ 0 |  | $ 0 |
[1] | Includes $1,895 million of money market funds that are classified as Fiduciary assets, Short-term investments or Cash and cash equivalents in the Condensed Consolidated Statements of Financial Position, depending on their nature and initial maturity.
[2] | Includes $1,850 million of money market funds that are classified as Fiduciary assets, Short-term investments or Cash and cash equivalents in the Condensed Consolidated Statements of Financial Position, depending on their nature and initial maturity.

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