v3.26.1
Financial Highlights (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Per Accumulation Unit Data:              
Rental income (in dollars per share) $ 13.383 $ 26.577 $ 28.407 $ 27.323      
Real estate property level expenses (in dollars per share) 5.745 11.694 13.098 12.858      
Real estate income, net (in dollars per share) 7.638 14.883 15.309 14.465      
Other income (in dollars per share) 2.957 6.533 7.209 7.539      
Total income (in dollars per share) 10.595 21.416 22.518 22.004      
Interest expense (in dollars per share) 0.900 1.225 1.117 1.339      
Expense charges (in dollars per share) 2.197 4.217 4.701 4.877      
Investment income, net (in dollars per share) 7.498 15.974 16.700 15.788      
Net realized and unrealized gain (loss) on investments and debt (in dollars per share) 2.579 2.341 (36.511) (91.657)      
Net increase (decrease) in Accumulation Unit Value (in dollars per share) 10.077 18.315 (19.811) (75.869)      
Accumulation Unit Value:              
Beginning of period (in dollars per share) 479.558 461.243 481.054 556.923      
End of period (in dollars per share) $ 489.635 $ 479.558 $ 461.243 $ 481.054      
Total return 2.10% 3.97% (4.12%) (13.62%)      
Ratios to Average net assets:              
Expense charges 0.90% 0.88% 0.99% 0.93%      
Investment income, net 3.07% 3.32% 3.52% 3.00%      
Portfolio turnover rate:              
Real estate properties 2.20% 6.90% 2.70% 1.40%      
Marketable securities 0.00% 0.00% 23.60% 21.60%      
Accumulation Units outstanding at end of period (millions) (in shares) 46.0 46.5 47.8 48.0      
Net assets end of period (millions) $ 22,951.1 $ 22,766.6 $ 22,486.9 $ 23,618.9 $ 22,736.2 $ 22,675.5 $ 22,580.6