Financial Instruments and Fair Value Measures - Fair Value Measures (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Assets
Foreign currency contracts	$ 235	$ 53
Liabilities
Foreign currency contracts	57	132
Quoted prices in active markets for identical assets (Level 1)
Liabilities
Total liabilities	69,907	70,384
Fair Value, Recurring [Member]
Assets
Cash and equivalents	41,142	39,924
Debt securities	3	3
Equity securities		24
Interest rate swap contracts	133	31
Total assets	41,380	40,004
Liabilities
Interest rate swap contracts	44	76
Contingent consideration	7,359	7,340
Total liabilities	7,416	7,472
Fair Value, Recurring [Member] \| Foreign currency contracts
Assets
Foreign currency contracts	102	22
Liabilities
Foreign currency contracts	13	56
Fair Value, Recurring [Member] \| Quoted prices in active markets for identical assets (Level 1)
Assets
Cash and equivalents	1,272	1,542
Debt securities	0	0
Equity securities		24
Interest rate swap contracts	0	0
Total assets	1,272	1,566
Liabilities
Interest rate swap contracts	0	0
Contingent consideration	0	0
Total liabilities	0	0
Fair Value, Recurring [Member] \| Quoted prices in active markets for identical assets (Level 1) \| Foreign currency contracts
Assets
Foreign currency contracts	0	0
Liabilities
Foreign currency contracts	0	0
Fair Value, Recurring [Member] \| Significant other observable inputs (Level 2)
Assets
Cash and equivalents	39,870	38,382
Debt securities	3	3
Equity securities		0
Interest rate swap contracts	133	31
Total assets	40,108	38,438
Liabilities
Interest rate swap contracts	44	76
Contingent consideration	0	0
Total liabilities	57	132
Fair Value, Recurring [Member] \| Significant other observable inputs (Level 2) \| Foreign currency contracts
Assets
Foreign currency contracts	102	22
Liabilities
Foreign currency contracts	13	56
Fair Value, Recurring [Member] \| Significant unobservable inputs (Level 3)
Assets
Cash and equivalents	0	0
Debt securities	0	0
Equity securities		0
Interest rate swap contracts	0	0
Total assets	0	0
Liabilities
Interest rate swap contracts	0	0
Contingent consideration	7,359	7,340
Total liabilities	7,359	7,340
Fair Value, Recurring [Member] \| Significant unobservable inputs (Level 3) \| Foreign currency contracts
Assets
Foreign currency contracts	0	0
Liabilities
Foreign currency contracts	$ 0	$ 0

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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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value, before 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 elected not to be offset. Excludes assets not subject to a master netting arrangement.

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