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Income Taxes (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) county | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) county
Income Tax Contingency [Line Items] |  |  |  |
Income tax expense (benefit) related to continuing operations | $ (1,189,000,000) | $ 47,000,000 | $ (1,011,000,000) | $ (111,000,000)
Reported income tax expense (benefit) rates (percent) | (16.10%) | 16.00% | (16.70%) | (194.70%)
Discrete tax benefit |  | $ 21,000,000 | $ 105,000,000 | $ 21,000,000
Number of counties that filed claims | county |  | 2 |  | 2
Deferred tax asset for the temporary difference arising from buyer's excess tax basis |  |  | 105,000,000 |
Tax benefit recognized for remeasurement of assets and liabilities held-for-sale to fair value |  |  |  | $ 0
Pre-tax impairment charge |  | $ 282,000,000 |  | 282,000,000
Unrecognized tax benefits | $ 1,500,000,000 |  | 1,500,000,000 |
Unrecognized tax benefits that would reduce income tax expense and the effective tax rate | 1,400,000,000 |  | 1,400,000,000 |
Increase in unrecognized tax benefits | 497,000,000 |  |  |
Possible decrease in unrecognized tax benefits during the next twelve months | 93,000,000 |  | 93,000,000 |
National Prescription Opioid Litigation |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |
Pre-tax expenses related to estimated litigation liability | 8,100,000,000 |  | 8,100,000,000 |
After-tax expenses related to estimated litigation liability | $ 6,700,000,000 |  | $ 6,700,000,000 |
Planned divestiture in Medical-Surgical Solutions business |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |
Discrete tax benefit |  | $ 24,000,000 |  | $ 24,000,000

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