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Supplemental Disclosures to the Consolidated Statements of Cash Flows (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2017 | Mar. 31, 2016
Supplemental Disclosure to the Consolidate Statements of Cash Flows [Line Items] |  |
Deferred and contingent consideration from prior years acquisition | $ 34 | $ 39
Contingent consideration from prior year's acquisitions | 8 | 14
Net charge for adjustments related to acquisition related accounts | (16) | 5
Payment of contingent consideration | 4 | 4
Non-cash issuance of common stock | 85 | 67
Stock-based compensation expense, equity awards | 28 | 20
Effective income tax rate reconciliation, share-based compensation, excess tax benefit, amount | 44 | 18
Prior Fiscal Periods Acquisitions |  |
Supplemental Disclosure to the Consolidate Statements of Cash Flows [Line Items] |  |
Deferred purchase consideration from prior years' acquisitions | 26 | 25
Contingent consideration from prior year's acquisitions | $ 12 | $ 18

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