Shareholders' Equity and Other Equity instruments - Summary of Issued Share Capital and Reserves Attributable To Shareholders (Detail) - EUR (€) € in Millions |
6 Months Ended | 12 Months Ended |
|---|---|---|
Jun. 30, 2026 |
Dec. 31, 2025 |
|
| Ordinary shares [member] | ||
| Summary of issued share capital and reserves attributable to shareholders [line items] | ||
| Share capital - par value | € 229 | € 229 |
| Beginning balance | 229 | 241 |
| Shares withdrawn | 0 | (12) |
| Ending balance | 229 | 229 |
| Shareholders of Aegon Ltd. [Member] | ||
| Summary of issued share capital and reserves attributable to shareholders [line items] | ||
| Share capital - par value | 229 | 229 |
| Share premium | 6,853 | 6,853 |
| Total share capital | 7,082 | 7,082 |
| Beginning balance | 229 | |
| Ending balance | € 229 | € 229 |