v3.26.3
Fair Value Disclosures - Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Jun. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Assets measured at fair value, beginning balance $ 275   $ 335 $ 367 $ 363
Realized and Unrealized Gains (Losses),Assets 3   2 3 3
Purchases, Assets 14   1 81 21
Sales and Maturities, Assets (7)   (96) (184) (145)
Issuances and other Settlements, Assets (28)   21 (28) 21
Transfers into Level 3, Assets 6   0 29 0
Transfers out of Level 3, Assets (36)   (17) (41) (17)
Assets measured at fair value, ending balance 227 $ 275 246 227 246
Total Net Unrealized Gains (Losses) Included in Earnings 3   1 (1) 11
Liabilities measured at fair value, beginning balance     4,569   4,431
Realized and Unrealized Gains (Losses), Liabilities     92   270
Purchases, Liabilities     0   0
Sales and Maturities, Liabilities     0   0
Issuances and other Settlements, Liabilities     3,398   3,358
Transfers into Level 3, Liabilities     0   0
Transfers out of Level 3, Liabilities     0   0
Liabilities measured at fair value, ending balance     8,059   8,059
Total Net Unrealized Gains (Losses) Included in Earnings     92   270
Contingent Consideration Liabilities [Member]          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Assets measured at fair value, beginning balance 7,875        
Assets measured at fair value, ending balance   7,875      
Liabilities measured at fair value, beginning balance     4,472 8,429 4,302
Realized and Unrealized Gains (Losses), Liabilities $ 563   $ 93 $ 22 $ 274
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Business Combination, Contingent Consideration, Liability, Current   Business Combination, Contingent Consideration, Liability, Current Business Combination, Contingent Consideration, Liability, Current Business Combination, Contingent Consideration, Liability, Current
Purchases, Liabilities $ 0   $ 0 $ 0 $ 0
Sales and Maturities, Liabilities 0   0 0 0
Issuances and other Settlements, Liabilities (2,580)   3,413 (2,593) 3,402
Transfers into Level 3, Liabilities 0   0 0 0
Transfers out of Level 3, Liabilities 0   0 0 0
Liabilities measured at fair value, ending balance 5,858   7,978 5,858 7,978
Total Net Unrealized Gains (Losses) Included in Earnings   563 93 22 274
Other Liabilities [Member]          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Liabilities measured at fair value, beginning balance     97   129
Realized and Unrealized Gains (Losses), Liabilities     (1)   (4)
Purchases, Liabilities     0   0
Sales and Maturities, Liabilities     0   0
Issuances and other Settlements, Liabilities     (15)   (44)
Transfers into Level 3, Liabilities     0   0
Transfers out of Level 3, Liabilities     0   0
Liabilities measured at fair value, ending balance     81   81
Total Net Unrealized Gains (Losses) Included in Earnings     $ (1)   $ (4)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]     Nonoperating Income (Expense)   Nonoperating Income (Expense)
Investments [Member]          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Assets measured at fair value, beginning balance 126   $ 171 216 $ 214
Realized and Unrealized Gains (Losses),Assets 7   0 9 (14)
Purchases, Assets 14   1 81 21
Sales and Maturities, Assets (7)   (96) (184) (145)
Issuances and other Settlements, Assets 0   21 0 21
Transfers into Level 3, Assets 6   0 29 0
Transfers out of Level 3, Assets (36)   (1) (41) (1)
Assets measured at fair value, ending balance 110 126 96 110 96
Total Net Unrealized Gains (Losses) Included in Earnings 7   (1) 5 (6)
Other Assets [Member]          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Assets measured at fair value, beginning balance 149   164 151 149
Realized and Unrealized Gains (Losses),Assets (4)   2 (6) 17
Purchases, Assets 0   0 0 0
Sales and Maturities, Assets 0   0 0 0
Issuances and other Settlements, Assets (28)   0 (28) 0
Transfers into Level 3, Assets 0   0 0 0
Transfers out of Level 3, Assets 0   (16) 0 (16)
Assets measured at fair value, ending balance 117 149 150 117 150
Total Net Unrealized Gains (Losses) Included in Earnings (4)   2 (6) 17
Debt securities [Member] | Trading [Member]          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Assets measured at fair value, beginning balance 46   7 7 7
Realized and Unrealized Gains (Losses),Assets 0   0 0 0
Purchases, Assets 4   0 62 0
Sales and Maturities, Assets 0   0 (26) 0
Issuances and other Settlements, Assets 0   0 0 0
Transfers into Level 3, Assets 0   0 7 0
Transfers out of Level 3, Assets (22)   0 (22) 0
Assets measured at fair value, ending balance 28 46 7 28 7
Total Net Unrealized Gains (Losses) Included in Earnings $ 0   $ 0 $ 0 $ 0
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Nonoperating Income (Expense)   Nonoperating Income (Expense) Nonoperating Income (Expense) Nonoperating Income (Expense)
Mutual Funds [Member] | Equity Securities Mutual Funds [Member]          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Assets measured at fair value, beginning balance $ 24     $ 136  
Realized and Unrealized Gains (Losses),Assets 2     6  
Purchases, Assets 9     15  
Sales and Maturities, Assets 0     (136)  
Issuances and other Settlements, Assets 0     0  
Transfers into Level 3, Assets 0     14  
Transfers out of Level 3, Assets (14)     (14)  
Assets measured at fair value, ending balance 21 24   21  
Total Net Unrealized Gains (Losses) Included in Earnings 2     6  
Loans [Member]          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Assets measured at fair value, beginning balance 56   $ 68 73 $ 72
Realized and Unrealized Gains (Losses),Assets 5   (1) 3 (6)
Purchases, Assets 1   1 4 6
Sales and Maturities, Assets (7)   0 (22) (3)
Issuances and other Settlements, Assets 0   21 0 21
Transfers into Level 3, Assets 6   0 8 0
Transfers out of Level 3, Assets 0   0 (5) (1)
Assets measured at fair value, ending balance 61 $ 56 89 61 89
Total Net Unrealized Gains (Losses) Included in Earnings $ 5   0 $ (1) (6)
Consolidated Variable Interest Entities [Member] | Loans [Member]          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Assets measured at fair value, beginning balance     96   135
Realized and Unrealized Gains (Losses),Assets     1   (8)
Purchases, Assets     0   15
Sales and Maturities, Assets     (96)   (142)
Issuances and other Settlements, Assets     0   0
Transfers into Level 3, Assets     0   0
Transfers out of Level 3, Assets     (1)   0
Assets measured at fair value, ending balance     0   0
Total Net Unrealized Gains (Losses) Included in Earnings     $ (0)   $ 0