| **Basis of Presentation and Significant Accounting Policies (Details) $ in Millions** |         | 3 Months Ended | 12 Months Ended |        |
|---------------------------------------------------------------------------------------|---------|----------------|-----------------|--------|
||
| **Organization, Consolidation and Presentation of Financial Statements [Abstract]**   |    |           |            |   |
| Number of accounting standards adopted | Accounting_standard                          | 4       |           |            | 11     |
| Number of business segments | Operating_Segment                                       |    | 3              | 2               |   |
| **New Accounting Pronouncements or Change in Accounting Principle [Line Items]**      |    |           |            |   |
| ROU assets                                                                            |    | $ 1,280        |            |   |
| Lease liabilities (long-term)                                                         |    | 1,043          |            |   |
| Accrued rebates and other accruals                                                    |    | 5,544          | $ 5,426         |   |
| Variable lease payments                                                               |    | $ 59           |            |   |
| Accounting Standards Update 2016-02 [Member]                                          |    |           |            |   |
| **New Accounting Pronouncements or Change in Accounting Principle [Line Items]**      |    |           |            |   |
| ROU assets                                                                            | $ 1,400 |           |            |   |
| Lease liabilities (long-term)                                                         | 1,400   |           |            |   |
| Cumulative effect adjustment to retained earnings, pre-tax                            | 30      |           |            |   |
| Cumulative effect adjustment to retained earnings, after-tax                          | $ 20    |           |            |   |
| Minimum [Member]                                                                      |    |           |            |   |
| **New Accounting Pronouncements or Change in Accounting Principle [Line Items]**      |    |           |            |   |
| Operating lease term                                                                  |    | 1 year         |            |   |
| Operating lease term, option to extend                                                |    | 5 years        |            |   |
| Maximum [Member]                                                                      |    |           |            |   |
| **New Accounting Pronouncements or Change in Accounting Principle [Line Items]**      |    |           |            |   |
| Operating lease term                                                                  |    | 30 years       |            |   |
| Operating lease term, option to extend                                                |    | 10 years       |            |   |

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Accruals for Medicaid rebates, Medicare rebates, performance-based contract rebates, sales allowances and chargebacks, which are substantially all are included in Other current liabilities in our consolidated balance sheets.
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Amount of the cumulative effect on retained earnings before related income tax effect.
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Amount of the cumulative effect on retained earnings net of related income tax effect.
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| - Definition
Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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| - Definition
Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.
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Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent.
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Amount of lessee's right to use underlying asset under operating lease.
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Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.
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