Operating Segment and Revenue Information - Schedule of Revenue by Type of Good or Service (Details) - JPY (¥) ¥ in Millions |
12 Months Ended | ||
|---|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
Mar. 31, 2023 |
|
| Disclosure of products and services [line items] | |||
| Revenue from contracts with customers | ¥ 4,581,551 | ¥ 4,263,762 | ¥ 4,027,478 |
| Sales of pharmaceutical products | |||
| Disclosure of products and services [line items] | |||
| Revenue from contracts with customers | 4,495,972 | 4,163,652 | 3,922,280 |
| Out-licensing and service income | |||
| Disclosure of products and services [line items] | |||
| Revenue from contracts with customers | ¥ 85,579 | ¥ 100,110 | ¥ 105,198 |