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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of liability recognized arising from contingent consideration in a business combination.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Fair value of financial and nonfinancial obligations.

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Amount of noncurrent assets classified as other.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Assets
Investments	$ 6,343	$ 7,261
Investments	636	456
Derivative assets	384	454
Liabilities
Contingent consideration	667	788	$ 919	$ 935
Derivative liabilities	195	160
Corporate notes and bonds
Assets
Investments	4,310	4,920
Asset-backed securities
Assets
Investments	$ 1,094	1,275
Liabilities
Primary weighted average life of collateral	5 years
U.S. government and agency securities
Assets
Investments	$ 832	892
Foreign government bonds
Assets
Investments	99	166
Mortgage-backed securities
Assets
Investments	8	8
Fair Value, Measurements, Recurring
Assets
Investments	6,343	7,132
Other assets	636	585
Derivative assets	384	454
Total assets	7,363	8,171
Liabilities
Contingent consideration	667	788
Derivative liabilities	195	160
Total liabilities	862	948
Fair Value, Measurements, Recurring \| Foreign exchange contracts
Assets
Derivative assets	194	241
Liabilities
Derivative liabilities	144	74
Fair Value, Measurements, Recurring \| Currency options
Assets
Derivative assets	190	213
Liabilities
Derivative liabilities	3	5
Fair Value, Measurements, Recurring \| Interest rate swap contracts
Liabilities
Derivative liabilities	48	81
Fair Value, Measurements, Recurring \| Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets
Investments	209	147
Other assets	483	364
Derivative assets	0	0
Total assets	692	511
Liabilities
Contingent consideration	0	0
Derivative liabilities	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring \| Quoted Prices In Active Markets for Identical Assets (Level 1) \| Foreign exchange contracts
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring \| Quoted Prices In Active Markets for Identical Assets (Level 1) \| Currency options
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring \| Quoted Prices In Active Markets for Identical Assets (Level 1) \| Interest rate swap contracts
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring \| Significant Other Observable Inputs (Level 2)
Assets
Investments	6,134	6,985
Other assets	153	221
Derivative assets	384	454
Total assets	6,671	7,660
Liabilities
Contingent consideration	0	0
Derivative liabilities	195	160
Total liabilities	195	160
Fair Value, Measurements, Recurring \| Significant Other Observable Inputs (Level 2) \| Foreign exchange contracts
Assets
Derivative assets	194	241
Liabilities
Derivative liabilities	144	74
Fair Value, Measurements, Recurring \| Significant Other Observable Inputs (Level 2) \| Currency options
Assets
Derivative assets	190	213
Liabilities
Derivative liabilities	3	5
Fair Value, Measurements, Recurring \| Significant Other Observable Inputs (Level 2) \| Interest rate swap contracts
Liabilities
Derivative liabilities	48	81
Fair Value, Measurements, Recurring \| Significant Unobservable Inputs (Level 3)
Assets
Investments	0	0
Other assets	0	0
Derivative assets	0	0
Total assets	0	0
Liabilities
Contingent consideration	667	788
Derivative liabilities	0	0
Total liabilities	667	788
Fair Value, Measurements, Recurring \| Significant Unobservable Inputs (Level 3) \| Foreign exchange contracts
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring \| Significant Unobservable Inputs (Level 3) \| Currency options
Assets
Derivative assets	0	0
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring \| Significant Unobservable Inputs (Level 3) \| Interest rate swap contracts
Liabilities
Derivative liabilities	0	0
Fair Value, Measurements, Recurring \| Corporate notes and bonds
Assets
Investments	4,231	4,835
Other assets	79	85
Fair Value, Measurements, Recurring \| Corporate notes and bonds \| Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets
Investments	0	0
Other assets	0	0
Fair Value, Measurements, Recurring \| Corporate notes and bonds \| Significant Other Observable Inputs (Level 2)
Assets
Investments	4,231	4,835
Other assets	79	85
Fair Value, Measurements, Recurring \| Corporate notes and bonds \| Significant Unobservable Inputs (Level 3)
Assets
Investments	0	0
Other assets	0	0
Fair Value, Measurements, Recurring \| Asset-backed securities
Assets
Investments	1,069	1,253
Other assets	25	22
Fair Value, Measurements, Recurring \| Asset-backed securities \| Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets
Investments	0	0
Other assets	0	0
Fair Value, Measurements, Recurring \| Asset-backed securities \| Significant Other Observable Inputs (Level 2)
Assets
Investments	1,069	1,253
Other assets	25	22
Fair Value, Measurements, Recurring \| Asset-backed securities \| Significant Unobservable Inputs (Level 3)
Assets
Investments	0	0
Other assets	0	0
Fair Value, Measurements, Recurring \| U.S. government and agency securities
Assets
Investments	735	731
Other assets	97	161
Fair Value, Measurements, Recurring \| U.S. government and agency securities \| Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets
Investments	0	0
Other assets	56	55
Fair Value, Measurements, Recurring \| U.S. government and agency securities \| Significant Other Observable Inputs (Level 2)
Assets
Investments	735	731
Other assets	41	106
Fair Value, Measurements, Recurring \| U.S. government and agency securities \| Significant Unobservable Inputs (Level 3)
Assets
Investments	0	0
Other assets	0	0
Fair Value, Measurements, Recurring \| Foreign government bonds
Assets
Investments	99	166
Fair Value, Measurements, Recurring \| Foreign government bonds \| Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets
Investments	0	0
Fair Value, Measurements, Recurring \| Foreign government bonds \| Significant Other Observable Inputs (Level 2)
Assets
Investments	99	166
Fair Value, Measurements, Recurring \| Foreign government bonds \| Significant Unobservable Inputs (Level 3)
Assets
Investments	0	0
Fair Value, Measurements, Recurring \| Mortgage-backed securities
Assets
Other assets	8	8
Fair Value, Measurements, Recurring \| Mortgage-backed securities \| Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets
Other assets	0	0
Fair Value, Measurements, Recurring \| Mortgage-backed securities \| Significant Other Observable Inputs (Level 2)
Assets
Other assets	8	8
Fair Value, Measurements, Recurring \| Mortgage-backed securities \| Significant Unobservable Inputs (Level 3)
Assets
Other assets	0	0
Fair Value, Measurements, Recurring \| Publicly traded equity securities
Assets
Investments	209	147
Other assets	427	309
Fair Value, Measurements, Recurring \| Publicly traded equity securities \| Quoted Prices In Active Markets for Identical Assets (Level 1)
Assets
Investments	209	147
Other assets	427	309
Fair Value, Measurements, Recurring \| Publicly traded equity securities \| Significant Other Observable Inputs (Level 2)
Assets
Investments	0	0
Other assets	0	0
Fair Value, Measurements, Recurring \| Publicly traded equity securities \| Significant Unobservable Inputs (Level 3)
Assets
Investments	0	0
Other assets	$ 0	$ 0