Investments in subsidiaries - Narrative (Details) - USD ($) $ in Billions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Disclosure of subsidiaries [line items] | ||
| Investments in subsidiaries | $ 157.7 | $ 152.3 |
| Increase (decrease) in investments in subsidiaries | 5.4 | |
| HSBC Asia Holdings Limited | ||
| Disclosure of subsidiaries [line items] | ||
| Increase (decrease) in investments in subsidiaries | 1.9 | |
| HSBC UK Bank plc | ||
| Disclosure of subsidiaries [line items] | ||
| Increase (decrease) in investments in subsidiaries | 0.7 | |
| HSBC Overseas Holdings (UK) Limited | ||
| Disclosure of subsidiaries [line items] | ||
| Investments in subsidiaries | 16.8 | 14.0 |
| Recoveries | 2.8 | |
| HSBC Overseas Holdings (UK) Limited | Accumulated impairment losses | ||
| Disclosure of subsidiaries [line items] | ||
| Investments in subsidiaries | $ 18.8 | $ 21.6 |