Fair Value Measurement - Carrying Value and Estimated Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Financial assets
Cash and due from banks	$ 22,896	$ 29,066
Deposits with banks	411,364	595,085
Federal funds sold and securities purchased under resale agreements	390,821	276,152
Investment securities, held-to-maturity	279,641	342,754
Loans, net of allowance for loan losses	42,137	38,851
Financial liabilities
Beneficial interests issued by consolidated VIEs	25,694	23,020
Carrying value
Financial assets
Cash and due from banks	22,900	29,100
Deposits with banks	411,400	595,100
Accrued interest and accounts receivable	122,300	107,100
Federal funds sold and securities purchased under resale agreements	21,900	16,300
Securities borrowed	144,800	130,300
Investment securities, held-to-maturity	300,000	369,800
Loans, net of allowance for loan losses	1,273,900	1,262,500
Other	85,200	76,100
Financial liabilities
Deposits	2,379,500	2,322,300
Federal funds purchased and securities loaned or sold under repurchase agreements	68,900	47,500
Short-term borrowings	22,300	24,700
Accounts payable and other liabilities	268,300	241,800
Beneficial interests issued by consolidated VIEs	25,700	23,000
Long-term debt	308,000	303,900
Wholesale lending-related commitments	2,800	3,000
Carrying value | First Republic
Financial liabilities
Wholesale lending-related commitments	769	1,100
Total estimated fair value
Financial assets
Cash and due from banks	22,900	29,100
Deposits with banks	411,400	595,100
Accrued interest and accounts receivable	122,300	107,100
Federal funds sold and securities purchased under resale agreements	21,900	16,300
Securities borrowed	144,800	130,300
Investment securities, held-to-maturity	279,600	342,800
Loans, net of allowance for loan losses	1,279,600	1,250,200
Other	85,400	76,300
Financial liabilities
Deposits	2,380,000	2,322,600
Federal funds purchased and securities loaned or sold under repurchase agreements	68,900	47,500
Short-term borrowings	22,400	24,700
Accounts payable and other liabilities	267,400	241,400
Beneficial interests issued by consolidated VIEs	25,800	23,000
Long-term debt	311,700	303,500
Wholesale lending-related commitments	4,500	4,800
Total estimated fair value | Level 1
Financial assets
Cash and due from banks	22,900	29,100
Deposits with banks	411,300	594,600
Accrued interest and accounts receivable	0	0
Federal funds sold and securities purchased under resale agreements	0	0
Securities borrowed	0	0
Investment securities, held-to-maturity	114,200	160,600
Loans, net of allowance for loan losses	0	0
Other	0	0
Financial liabilities
Deposits	0	0
Federal funds purchased and securities loaned or sold under repurchase agreements	0	0
Short-term borrowings	0	0
Accounts payable and other liabilities	0	0
Beneficial interests issued by consolidated VIEs	0	0
Long-term debt	0	0
Wholesale lending-related commitments	0	0
Total estimated fair value | Level 2
Financial assets
Cash and due from banks	0	0
Deposits with banks	100	500
Accrued interest and accounts receivable	122,200	107,000
Federal funds sold and securities purchased under resale agreements	21,900	16,300
Securities borrowed	144,800	130,300
Investment securities, held-to-maturity	165,400	182,200
Loans, net of allowance for loan losses	284,400	285,600
Other	83,800	74,900
Financial liabilities
Deposits	2,380,000	2,322,600
Federal funds purchased and securities loaned or sold under repurchase agreements	68,900	47,500
Short-term borrowings	22,400	24,700
Accounts payable and other liabilities	255,000	233,300
Beneficial interests issued by consolidated VIEs	25,800	23,000
Long-term debt	259,800	252,200
Wholesale lending-related commitments	0	0
Total estimated fair value | Level 3
Financial assets
Cash and due from banks	0	0
Deposits with banks	0	0
Accrued interest and accounts receivable	100	100
Federal funds sold and securities purchased under resale agreements	0	0
Securities borrowed	0	0
Investment securities, held-to-maturity	0	0
Loans, net of allowance for loan losses	995,200	964,600
Other	1,600	1,400
Financial liabilities
Deposits	0	0
Federal funds purchased and securities loaned or sold under repurchase agreements	0	0
Short-term borrowings	0	0
Accounts payable and other liabilities	12,400	8,100
Beneficial interests issued by consolidated VIEs	0	0
Long-term debt	51,900	51,300
Wholesale lending-related commitments	$ 4,500	$ 4,800