Fair Value Disclosures - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities	$ 1,964	$ 1,823
Equity securities	2,208	1,950
Loans held by CIPs	119	145
Separate account assets	53,655	52,811
Separate account collateral liabilities under securities lending agreements	5,803	6,059
Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	2,208	1,950
Investments Measured at NAV [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	108	86
Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	2,494	2,370
Equity securities	2,208	1,950
Total equity method	2,833	2,783
Loans held by CIPs	119	145
Federal Reserve Bank stock	93	93
Carried interest	1,987	1,983
Other investments	791	445
Total investments	10,525	9,769
Other assets	159	156
Separate account assets	53,655	52,811
Total separate account collateral held under securities lending agreements	5,803	6,059
Total	70,142	68,795
Separate account collateral liabilities under securities lending agreements	5,803	6,059
Contingent consideration liabilities	4,390	4,302
Other liabilities	121	175
Total liabilities measured at fair value	10,314	10,536
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	0	0
Equity securities	2,208	1,950
Total equity method	301	347
Loans held by CIPs	0	0
Federal Reserve Bank stock	0	0
Carried interest	0	0
Other investments	105	18
Total investments	2,614	2,315
Other assets	0	0
Separate account assets	33,141	32,933
Total separate account collateral held under securities lending agreements	2,134	2,719
Total	37,889	37,967
Separate account collateral liabilities under securities lending agreements	2,134	2,719
Contingent consideration liabilities	0	0
Other liabilities	0	0
Total liabilities measured at fair value	2,134	2,719
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	1,885	1,744
Equity securities	0	0
Total equity method	133	131
Loans held by CIPs	12	10
Federal Reserve Bank stock	0	0
Carried interest	0	0
Other investments	0	0
Total investments	2,030	1,885
Other assets	7	7
Separate account assets	20,064	19,346
Total separate account collateral held under securities lending agreements	3,669	3,340
Total	25,770	24,578
Separate account collateral liabilities under securities lending agreements	3,669	3,340
Contingent consideration liabilities	0	0
Other liabilities	19	46
Total liabilities measured at fair value	3,688	3,386
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	79	79
Equity securities	0	0
Total equity method	0	0
Loans held by CIPs	107	135
Federal Reserve Bank stock	0	0
Carried interest	0	0
Other investments	0	0
Total investments	186	214
Other assets	152	149
Separate account assets	0	0
Total separate account collateral held under securities lending agreements	0	0
Total	338	363
Separate account collateral liabilities under securities lending agreements	0	0
Contingent consideration liabilities	4,390	4,302
Other liabilities	102	129
Total liabilities measured at fair value	4,492	4,431
Fair Value, Measurements, Recurring [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities	1,964	1,823
Held-to-maturity investments	530	547
Fair Value, Measurements, Recurring [Member] | Debt Securities/ Fixed Income Mutual Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities	0	0
Held-to-maturity investments	0	0
Fair Value, Measurements, Recurring [Member] | Debt Securities/ Fixed Income Mutual Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities	1,885	1,744
Held-to-maturity investments	0	0
Fair Value, Measurements, Recurring [Member] | Debt Securities/ Fixed Income Mutual Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities	79	79
Held-to-maturity investments	0	0
Fair Value, Measurements, Recurring [Member] | Hedge Funds/Funds of Hedge Funds/Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	443	552
Fair Value, Measurements, Recurring [Member] | Hedge Funds/Funds of Hedge Funds/Other [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Hedge Funds/Funds of Hedge Funds/Other [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Hedge Funds/Funds of Hedge Funds/Other [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Equity Fixed Income And Multi Asset Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	434	478
Fair Value, Measurements, Recurring [Member] | Equity Fixed Income And Multi Asset Mutual Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	301	347
Fair Value, Measurements, Recurring [Member] | Equity Fixed Income And Multi Asset Mutual Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	133	131
Fair Value, Measurements, Recurring [Member] | Equity Fixed Income And Multi Asset Mutual Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	1,123	1,060
Fair Value, Measurements, Recurring [Member] | Private/ Public Equity [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Private/ Public Equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Private/ Public Equity [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Real Assets Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	568	520
Fair Value, Measurements, Recurring [Member] | Real Assets Funds [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Real Assets Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Real Assets Funds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Investments Related To Deferred Cash Compensation Plans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	265	173
Fair Value, Measurements, Recurring [Member] | Investments Related To Deferred Cash Compensation Plans [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Investments Related To Deferred Cash Compensation Plans [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Investments Related To Deferred Cash Compensation Plans [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	2,134	2,719
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	2,134	2,719
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	0	0
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	0	0
Fair Value, Measurements, Recurring [Member] | Debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	3,669	3,340
Fair Value, Measurements, Recurring [Member] | Debt securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	0	0
Fair Value, Measurements, Recurring [Member] | Debt securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	3,669	3,340
Fair Value, Measurements, Recurring [Member] | Debt securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	0	0
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt securities	0	0
Equity securities	0	0
Total equity method	2,399	2,305
Loans held by CIPs	0	0
Federal Reserve Bank stock	0	0
Carried interest	0	0
Other investments	528	274
Total investments	2,927	2,579
Other assets	0	0
Separate account assets	0	0
Total separate account collateral held under securities lending agreements	0	0
Total	2,927	2,579
Separate account collateral liabilities under securities lending agreements	0	0
Contingent consideration liabilities	0	0
Other liabilities	0	0
Total liabilities measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Debt Securities/ Fixed Income Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities	0	0
Held-to-maturity investments	0	0
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Hedge Funds/Funds of Hedge Funds/Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	443	552
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Equity Fixed Income And Multi Asset Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	1,123	1,060
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Real Assets Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	568	520
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Investments Related To Deferred Cash Compensation Plans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	265	173
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	0	0
Fair Value, Measurements, Recurring [Member] | Investments Measured at NAV [Member] | Debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	0	0
Fair Value, Measurements, Recurring [Member] | Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities	0	0
Held-to-maturity investments	530	547
Total debt securities	530	547
Equity securities	0	0
Total equity method	0	0
Loans held by CIPs	0	0
Federal Reserve Bank stock	93	93
Carried interest	1,987	1,983
Other investments	158	153
Total investments	2,768	2,776
Other assets	0	0
Separate account assets	450	532
Total separate account collateral held under securities lending agreements	0	0
Total	3,218	3,308
Separate account collateral liabilities under securities lending agreements	0	0
Contingent consideration liabilities	0	0
Other liabilities	0	0
Total liabilities measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Other [Member] | Hedge Funds/Funds of Hedge Funds/Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Other [Member] | Equity Fixed Income And Multi Asset Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Other [Member] | Private/ Public Equity [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Other [Member] | Real Assets Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Other [Member] | Investments Related To Deferred Cash Compensation Plans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total equity method	0	0
Fair Value, Measurements, Recurring [Member] | Other [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	0	0
Fair Value, Measurements, Recurring [Member] | Other [Member] | Debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total separate account collateral held under securities lending agreements	$ 0	$ 0