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Income Taxes - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2025 | Sep. 30, 2024 | Mar. 31, 2024 | Jun. 30, 2023 | Mar. 31, 2026 | Mar. 31, 2025 | Mar. 31, 2024 | Mar. 31, 2023
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Liquidation of investment |  |  |  |  | $ (158) |  |  |
Valuation allowance release |  |  |  |  |  | $ 0 | $ (157) |
Net tax benefit on intellectual property repatriation and sales |  |  |  |  |  | (258) | (104) |
Tax expense (benefit), intra-entity transfers of assets other than inventory, amount | $ 214 | $ 44 | $ (43) | $ 147 |  |  |  |
Less: valuation allowance | (644) |  |  |  | (769) | (644) |  |
Unrecognized tax benefits | 1,532 |  | $ 1,463 |  | 1,574 | 1,532 | 1,463 | $ 1,399
Unrecognized tax benefits that would impact effective tax rate |  |  |  |  | 1,500 |  |  |
Income tax expense (benefit), before any tax effect, related to accrued interest and penalties |  |  |  |  | 74 | 80 | $ 84 |
Accrued interest and penalties on unrecognized tax benefits | $ 302 |  |  |  | 376 | $ 302 |  |
Undistributed earnings of foreign operations |  |  |  |  | 3,700 |  |  |
Minimum |  |  |  |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Tax liability increase due to proposed adjustment to taxable income |  |  |  |  | 600 |  |  |
Maximum |  |  |  |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Tax liability increase due to proposed adjustment to taxable income |  |  |  |  | 700 |  |  |
Luxembourg |  |  |  |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Valuation allowance release |  |  |  |  | (119) |  |  |
Federal |  |  |  |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Federal, state and foreign net operating loss carryforwards |  |  |  |  | 53 |  |  |
Federal | Capital Loss Carryforward |  |  |  |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Federal, state and foreign net operating loss carryforwards |  |  |  |  | 801 |  |  |
State |  |  |  |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Federal, state and foreign net operating loss carryforwards |  |  |  |  | 4,000 |  |  |
State | Capital Loss Carryforward |  |  |  |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Federal, state and foreign net operating loss carryforwards |  |  |  |  | 1,400 |  |  |
Foreign Tax Jurisdiction |  |  |  |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Federal, state and foreign net operating loss carryforwards |  |  |  |  | 1,200 |  |  |
Foreign Tax Jurisdiction | Capital Loss Carryforward |  |  |  |  |  |  |  |
Income Tax Contingency [Line Items] |  |  |  |  |  |  |  |
Federal, state and foreign net operating loss carryforwards |  |  |  |  | $ 1,200 |  |  |

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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-2 + Details
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