v3.25.4
Financial Highlights - Schedule of Capital Transactions and Differing Fee Arrangements (Detail)
 12 Months Ended
Dec. 31, 2025
$ / shares
shares
Per Unit Data  
Net Asset Value, End of Period $ 25
Class I Units [Member]  
Per Unit Data  
Net Asset Value, Beginning of Period 0 [1]
Proceeds from Units Issued 25 [1]
Net Investment Income 0.69 [1]
Net Realized and Unrealized Gain (Loss) on Investments and Translation of Assets and Liabilities in Foreign Currencies 2.57 [1]
Net Change in Unrealized Gain (Loss) on Investment in the Aggregator 2.57 [1]
Net Increase in Net Assets Resulting from Investment Operations 3.26 [1]
Servicing Fees 0 [1]
Distributions (0.71) [1]
Net Increase in Net Assets 2.54 [1]
Net Asset Value, End of Period $ 27.54 [1]
Units Outstanding, End of Period | shares 83,138,103 [1]
Total Return Based on Net Asset Value 13.02% [1],[2]
Ratios to Weighted-Average Net Assets (Non-Annualized)  
Expenses without Waivers 0.93% [1],[3]
Warehousing Fees Waivers (0.83%) [1]
Total Expenses 0.09% [1]
Net Investment Income 4.39% [1]
Class S Units [Member]  
Per Unit Data  
Net Asset Value, Beginning of Period $ 0 [1]
Proceeds from Units Issued 25 [1]
Net Investment Income 0.68 [1]
Net Realized and Unrealized Gain (Loss) on Investments and Translation of Assets and Liabilities in Foreign Currencies 2.55 [1]
Net Change in Unrealized Gain (Loss) on Investment in the Aggregator 2.55 [1]
Net Increase in Net Assets Resulting from Investment Operations 3.24 [1]
Servicing Fees (1.78) [1]
Distributions (0.71) [1]
Net Increase in Net Assets 0.74 [1]
Net Asset Value, End of Period $ 25.74 [1]
Units Outstanding, End of Period | shares 41,962,043 [1]
Total Return Based on Net Asset Value 5.81% [1],[2]
Ratios to Weighted-Average Net Assets (Non-Annualized)  
Expenses without Waivers 0.94% [1],[3]
Warehousing Fees Waivers (0.85%) [1]
Total Expenses 0.10% [1]
Net Investment Income 4.40% [1]
Class D Units [Member]  
Per Unit Data  
Net Asset Value, Beginning of Period $ 0 [1]
Proceeds from Units Issued 25 [1]
Net Investment Income 0.69 [1]
Net Realized and Unrealized Gain (Loss) on Investments and Translation of Assets and Liabilities in Foreign Currencies 2.55 [1]
Net Change in Unrealized Gain (Loss) on Investment in the Aggregator 2.55 [1]
Net Increase in Net Assets Resulting from Investment Operations 3.24 [1]
Servicing Fees (0.54) [1]
Distributions (0.71) [1]
Net Increase in Net Assets 1.99 [1]
Net Asset Value, End of Period $ 26.99 [1]
Units Outstanding, End of Period | shares 4,271,682 [1]
Total Return Based on Net Asset Value 10.82% [1],[2]
Ratios to Weighted-Average Net Assets (Non-Annualized)  
Expenses without Waivers 0.93% [1],[3]
Warehousing Fees Waivers (0.84%) [1]
Total Expenses 0.10% [1]
Net Investment Income 4.47% [1]
BXINFRA Aggregator (CYM) L.P. [Member]  
Per Unit Data  
Net Asset Value, End of Period $ 25
BXINFRA Aggregator (CYM) L.P. [Member] | Class A Units [Member]  
Per Unit Data  
Net Asset Value, Beginning of Period 0 [1]
Proceeds from Units Issued 25 [1]
Net Investment Income 0.16 [1]
Net Realized and Unrealized Gain (Loss) on Investments and Translation of Assets and Liabilities in Foreign Currencies 3.1 [1]
Net Change in Unrealized Gain (Loss) on Investment in the Aggregator 3.1 [1]
Distributions (0.72) [1]
Net Increase in Net Assets 3.27 [1]
Net Asset Value, End of Period $ 27.55 [1]
Units Outstanding, End of Period | shares 138,551,291 [1]
Total Return Based on Net Asset Value 13.06% [1],[4]
Ratios to Weighted-Average Net Assets (Non-Annualized)  
Expenses without Waivers 2.27% [1],[5]
Expenses and Management Fees Waivers (0.47%) [1],[5]
Accrued Performance Participation Allocation 1.98% [1]
Total Expenses 3.78% [1]
Net Investment Income 0.17% [1]
[1] Amounts may not add due to rounding.
[2] Total return is calculated as the change in Net Asset Value per Unit during the period, plus distributions per Unit (assuming dividends and distributions are reinvested in accordance with BXINFRA U.S.’s distribution reinvestment plan) divided by the initial Net Asset Value per Unit of $25.00. Total return does not include upfront transaction fees, if any.
[3] Expense ratio includes Management Fees, Organizational Expenses, Professional Fees, Deferred Offering Costs Amortization, Administration Fees and Other.
[4] Total return is calculated as the change in Net Asset Value per Aggregator Unit during the period, plus distributions per Aggregator Unit (assuming dividends and distributions are reinvested in accordance with the Aggregator’s distribution reinvestment plan) divided by the initial Net Asset Value per Aggregator Unit of $25.00. Total return does not include upfront transaction fees, if any.
[5] Expense ratio includes Management Fees, Organizational Expenses, Professional Fees, Interest Expense, Deferred Offering Costs Amortization, Administration Fees and Other.