v3.25.4
Fair Value Hierarchy - Investments Accounted for at Fair Value (Detail) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value $ 124,182 $ 104,742
Investments in funds at NAV 1,739 2,547
Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 122,443 102,195
Level 1 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 98,462 80,518
Level 2 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 9,570 7,535
Level 3 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 14,411 14,142
U.S. | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 92,049 75,410
U.S. | Level 1 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 90,582 75,410
U.S. | Level 2 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 1,467 0
U.S. | Level 3 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 0 0
Non-U.S. | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 7,199 4,110
Non-U.S. | Level 1 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 7,195 4,048
Non-U.S. | Level 2 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 4 62
Non-U.S. | Level 3 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 0 0
Corporate debt securities | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 7,039 7,276
Corporate debt securities | Level 1 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 139 137
Corporate debt securities | Level 2 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 2,621 2,629
Corporate debt securities | Level 3 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 4,279 4,510
Securities backed by real estate | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 312 569
Securities backed by real estate | Level 1 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 0 0
Securities backed by real estate | Level 2 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 6 7
Securities backed by real estate | Level 3 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 306 562
Money market instruments | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 2,333 1,780
Money market instruments | Level 1 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 78 327
Money market instruments | Level 2 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 2,255 1,453
Money market instruments | Level 3 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 0 0
Other debt obligations | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 354 403
Other debt obligations | Level 1 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 9 22
Other debt obligations | Level 2 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 0 53
Other debt obligations | Level 3 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 345 328
Equity securities | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 13,157 12,647
Equity securities | Level 1 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 459 574
Equity securities | Level 2 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value 3,217 3,331
Equity securities | Level 3 | Investments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments at fair value $ 9,481 $ 8,742