Acquisitions, Divestitures, Equity-Method Investments, Licensing Arrangements and Collaborative Arrangements - Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions (Details) - USD ($) $ in Millions |
12 Months Ended | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|||||||||||||||||
| Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] | |||||||||||||||||||
| Revenues | [1] | $ 41,908 | $ 41,172 | $ 40,825 | |||||||||||||||
| Cost of sales | [2] | (8,692) | (8,251) | (8,987) | |||||||||||||||
| Selling, informational and administrative expenses | [2] | (11,615) | (12,750) | (12,612) | |||||||||||||||
| Research and development expenses | [2] | (9,405) | (8,394) | (7,760) | |||||||||||||||
| Other income/(deductions)—net | (669) | (3,314) | (2,077) | ||||||||||||||||
| Collaborative Arrangement [Member] | |||||||||||||||||||
| Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] | |||||||||||||||||||
| Revenues | 5,703 | 4,953 | 4,107 | ||||||||||||||||
| Cost of sales | [3] | (61) | (52) | (34) | |||||||||||||||
| Selling, informational and administrative expenses | [4] | (194) | (176) | (92) | |||||||||||||||
| Research and development expenses | [5] | (192) | 104 | 162 | |||||||||||||||
| Other income/(deductions)—net | [6] | 567 | 362 | 281 | |||||||||||||||
| Product [Member] | Collaborative Arrangement [Member] | |||||||||||||||||||
| Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] | |||||||||||||||||||
| Revenues | [7] | 284 | 305 | 268 | |||||||||||||||
| Co-promotion [Member] | Collaborative Arrangement [Member] | |||||||||||||||||||
| Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] | |||||||||||||||||||
| Revenues | [8] | $ 5,418 | $ 4,648 | $ 3,838 | |||||||||||||||
| |||||||||||||||||||