Financial Highlights - Schedule of condensed financial information for an accumulation unit of the account (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |
6 Months Ended | 12 Months Ended | |||||
|---|---|---|---|---|---|---|---|
Jun. 30, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Mar. 31, 2025 |
Jun. 30, 2024 |
Mar. 31, 2024 |
|
| Per Accumulation Unit Data: | |||||||
| Rental income (in dollars per share) | $ 13.404 | $ 28.407 | $ 27.323 | $ 23.751 | |||
| Real estate property level expenses (in dollars per share) | 5.926 | 13.098 | 12.858 | 11.042 | |||
| Real estate income, net (in dollars per share) | 7.478 | 15.309 | 14.465 | 12.709 | |||
| Other income (in dollars per share) | 3.714 | 7.209 | 7.539 | 6.559 | |||
| Total income (in dollars per share) | 11.192 | 22.518 | 22.004 | 19.268 | |||
| Interest expense (in dollars per share) | 0.423 | 1.117 | 1.339 | 0.520 | |||
| Expense charges (in dollars per share) | 2.093 | 4.701 | 4.877 | 4.601 | |||
| Investment income, net (in dollars per share) | 8.676 | 16.700 | 15.788 | 14.147 | |||
| Net realized and unrealized (loss) gain on investments and debt (in dollars per share) | (0.353) | (36.511) | (91.657) | 28.011 | |||
| Net (decrease) increase in Accumulation Unit Value (in dollars per share) | 8.323 | (19.811) | (75.869) | 42.158 | |||
| Accumulation Unit Value: | |||||||
| Beginning of period (in dollars per share) | 461.243 | 481.054 | 556.923 | 514.765 | |||
| End of period (in dollars per share) | $ 469.566 | $ 461.243 | $ 481.054 | $ 556.923 | |||
| Total return | 1.81% | (4.12%) | (13.62%) | 8.19% | |||
| Ratios to Average net assets: | |||||||
| Expense charges | 0.88% | 0.99% | 0.93% | 0.89% | |||
| Investment income, net | 3.65% | 3.52% | 3.00% | 2.45% | |||
| Portfolio turnover rate: | |||||||
| Real estate properties | 3.30% | 2.70% | 1.40% | 5.60% | |||
| Marketable securities | 0.00% | 23.60% | 21.60% | 4.70% | |||
| Accumulation Units outstanding at end of period (millions) (in shares) | 47.3 | 47.8 | 48.0 | 52.1 | |||
| Net assets end of period (millions) | $ 22,675.5 | $ 22,486.9 | $ 23,618.9 | $ 29,658.1 | $ 22,580.6 | $ 22,525.8 | $ 22,969.6 |