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Segments of Business - Schedule of Segment Information (Details) $ in Millions | 12 Months Ended
--- | ---
Mar. 31, 2026 USD ($) segment | Mar. 31, 2025 USD ($) | Mar. 31, 2024 USD ($)
Segment revenues |  |  |
Revenues | $ 403,430 | $ 359,051 | $ 308,951
Other segment expense, net |  |  |
Total other expense, net | 396,051 | 353,631 | 304,059
Segment operating profit |  |  |
Subtotal | 7,379 | 5,420 | 4,892
Interest expense | (247) | (265) | (252)
Income before income taxes | 6,201 | 4,359 | 3,789
Segment depreciation and amortization |  |  |
Total segment depreciation and amortization | 729 | 636 | 635
Segment expenditures for long-lived assets |  |  |
Total segment expenditures for long-lived assets | $ 745 | 859 | 687
Number of reportable segments | segment | 4 |  |
Provision for bad debts | $ (100) | 130 | (819)
Charge associated with last-in, first-out inventory method | (210) | 82 | (157)
Restructuring, impairment, and related charges, net | 245 | 344 | 115
Income (loss) from equity method investments | (7) | (9) | (4)
Other, net | 44 | (38) | 34
Net gains (losses) on investments in equity securities |  | 101 | (24)
Rx Savings Solutions, LLC |  |  |
Segment expenditures for long-lived assets |  |  |
Fair value adjustment gain |  |  | (78)
North American Pharmaceutical |  |  |
Segment expenditures for long-lived assets |  |  |
Provision for bad debts |  | 206 | (725)
North American Pharmaceutical | Held-for-sale | Canadian Retail Disposal Group |  |  |
Segment expenditures for long-lived assets |  |  |
Canadian businesses held for sale |  | 605 |
Operating Segments | Norway Disposal Group |  |  |
Segment expenditures for long-lived assets |  |  |
Other, net | 503 |  |
Operating Segments | North American Pharmaceutical |  |  |
Segment revenues |  |  |
Revenues | 336,652 | 304,507 | 261,368
Other segment expense, net |  |  |
Total other expense, net | 332,994 | 301,562 | 259,030
Segment operating profit |  |  |
Subtotal | 3,658 | 2,945 | 2,338
Segment depreciation and amortization |  |  |
Total segment depreciation and amortization | 134 | 155 | 197
Segment expenditures for long-lived assets |  |  |
Total segment expenditures for long-lived assets | $ 334 | $ 243 | $ 159
Revenue derived from services (less than) (as a percent) | 1.00% | 1.00% | 1.00%
Provision for bad debts | $ 210 |  | $ 157
Charge associated with last-in, first-out inventory method |  | $ 82 |
Net cash proceeds from settlements | 23 | 444 | 244
Restructuring, impairment, and related charges, net | 24 | 59 | 20
Income (loss) from equity method investments |  | 43 |
Operating Segments | North American Pharmaceutical | National Prescription Opiate Litigation |  |  |
Segment expenditures for long-lived assets |  |  |
Pre-tax charges related to estimated litigation liability |  | 57 | 74
Operating Segments | Oncology & Multispecialty |  |  |
Segment revenues |  |  |
Revenues | 48,423 | 36,862 | 30,490
Other segment expense, net |  |  |
Total other expense, net | 47,274 | 36,095 | 29,783
Segment operating profit |  |  |
Subtotal | 1,149 | 767 | 707
Segment depreciation and amortization |  |  |
Total segment depreciation and amortization | 240 | 148 | 137
Segment expenditures for long-lived assets |  |  |
Total segment expenditures for long-lived assets | $ 78 | $ 88 | $ 96
Revenue derived from services (less than) (as a percent) | 7.00% | 7.00% | 7.00%
Restructuring, impairment, and related charges, net | $ 0 | $ 1 | $ 9
Gain from cost and equity method investments | 51 |  |
Operating Segments | Oncology & Multispecialty | PRISM Vision and Core Ventures |  |  |
Segment expenditures for long-lived assets |  |  |
Integration-related cost, expense | 96 |  |
Operating Segments | Prescription Technology Solutions |  |  |
Segment revenues |  |  |
Revenues | 5,805 | 5,216 | 4,769
Other segment expense, net |  |  |
Total other expense, net | 4,761 | 4,341 | 3,934
Segment operating profit |  |  |
Subtotal | 1,044 | 875 | 835
Segment depreciation and amortization |  |  |
Total segment depreciation and amortization | 82 | 86 | 84
Segment expenditures for long-lived assets |  |  |
Total segment expenditures for long-lived assets | $ 4 | $ 11 | $ 31
Revenue derived from services (less than) (as a percent) | 43.00% | 43.00% | 43.00%
Restructuring, impairment, and related charges, net | $ 20 | $ 12 | $ 11
Operating Segments | Medical-Surgical Solutions |  |  |
Segment revenues |  |  |
Revenues | 11,507 | 11,380 | 11,309
Other segment expense, net |  |  |
Total other expense, net | 10,569 | 10,601 | 10,354
Segment operating profit |  |  |
Subtotal | 938 | 779 | 955
Segment depreciation and amortization |  |  |
Total segment depreciation and amortization | 96 | 91 | 82
Segment expenditures for long-lived assets |  |  |
Total segment expenditures for long-lived assets | $ 94 | $ 163 | $ 159
Revenue derived from services (less than) (as a percent) | 1.00% | 1.00% | 1.00%
Restructuring, impairment, and related charges, net | $ 43 | $ 204 | $ 11
Separation costs | 25 |  |
Other |  |  |
Segment revenues |  |  |
Revenues | 1,043 | 1,086 | 1,015
Other segment expense, net |  |  |
Total other expense, net | 453 | 1,032 | 958
Segment operating profit |  |  |
Subtotal | 590 | 54 | 57
Segment depreciation and amortization |  |  |
Total segment depreciation and amortization | 4 | 18 | 14
Segment expenditures for long-lived assets |  |  |
Total segment expenditures for long-lived assets | 10 | 17 | 13
Corporate & Other |  |  |
Segment operating profit |  |  |
Corporate expenses, net | (931) | (796) | (851)
Interest expense | (247) | (265) | (252)
Segment depreciation and amortization |  |  |
Total segment depreciation and amortization | 173 | 138 | 121
Segment expenditures for long-lived assets |  |  |
Total segment expenditures for long-lived assets | 225 | 337 | 229
Restructuring, impairment, and related charges, net | 158 | 68 | 64
Other, net |  | (87) |
Net gains (losses) on investments in equity securities |  | 101 | (24)
Corporate & Other | National Prescription Opiate Litigation |  |  |
Segment expenditures for long-lived assets |  |  |
Litigation settlement payments | 11 | 14 | 35
Corporate & Other | National Prescription Opiate Litigation |  |  |
Segment expenditures for long-lived assets |  |  |
Pre-tax charges related to estimated litigation liability |  | 51 | $ 73
Corporate & Other | Canadian Retail Disposal Group |  |  |
Segment expenditures for long-lived assets |  |  |
Other comprehensive loss |  | $ 62 |
Corporate & Other | Norway Disposal Group |  |  |
Segment expenditures for long-lived assets |  |  |
Other, net | 23 |  |
Corporate & Other | Medical-Surgical Solutions |  |  |
Segment expenditures for long-lived assets |  |  |
Separation costs | $ 52 |  |

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