Fair Value Measurement - Carrying Value and Estimated Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Financial assets
Cash and due from banks	$ 21,742	$ 23,372
Deposits with banks	321,596	445,945
Federal funds sold and securities purchased under resale agreements	336,426	295,001
Investment securities, held-to-maturity	253,344	247,900
Loans, net of allowance for loan losses	70,684	41,350
Financial liabilities
Beneficial interests issued by consolidated VIEs	27,951	27,323
Carrying value
Financial assets
Cash and due from banks	21,700	23,400
Deposits with banks	321,600	445,900
Accrued interest and accounts receivable	111,100	101,100
Federal funds sold and securities purchased under resale agreements	9,400	8,200
Securities borrowed	188,100	135,600
Investment securities, held-to-maturity	270,100	274,500
Loans, net of allowance for loan losses	1,397,000	1,282,300
Other	93,000	82,700
Financial liabilities
Deposits	2,538,400	2,372,300
Federal funds purchased and securities loaned or sold under repurchase agreements	82,200	70,500
Short-term borrowings	32,300	26,400
Accounts payable and other liabilities	262,600	232,800
Beneficial interests issued by consolidated VIEs	27,900	27,300
Long-term debt	300,600	300,600
Wholesale lending-related commitments	3,200	2,700
Fair value
Financial assets
Cash and due from banks	21,700	23,400
Deposits with banks	321,600	445,900
Accrued interest and accounts receivable	111,100	101,100
Federal funds sold and securities purchased under resale agreements	9,400	8,200
Securities borrowed	188,100	135,600
Investment securities, held-to-maturity	253,300	247,900
Loans, net of allowance for loan losses	1,403,800	1,276,500
Other	93,200	82,900
Financial liabilities
Deposits	2,538,800	2,372,500
Federal funds purchased and securities loaned or sold under repurchase agreements	82,200	70,500
Short-term borrowings	32,300	26,300
Accounts payable and other liabilities	261,700	232,200
Beneficial interests issued by consolidated VIEs	28,000	27,400
Long-term debt	305,100	301,900
Wholesale lending-related commitments	4,500	4,400
Fair value | Level 1
Financial assets
Cash and due from banks	21,700	23,400
Deposits with banks	321,600	445,800
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	126,400	97,400
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
Fair value | Level 2
Financial assets
Cash and due from banks	0	0
Deposits with banks	0	100
Accrued interest and accounts receivable	111,000	101,000
Federal funds sold and securities purchased under resale agreements	9,400	8,200
Securities borrowed	188,100	135,600
Investment securities, held-to-maturity	126,900	150,500
Loans, net of allowance for loan losses	314,600	268,700
Other	91,700	81,300
Financial liabilities
Deposits	2,538,800	2,372,500
Federal funds purchased and securities loaned or sold under repurchase agreements	82,200	70,500
Short-term borrowings	32,300	26,300
Accounts payable and other liabilities	248,700	219,600
Beneficial interests issued by consolidated VIEs	28,000	27,400
Long-term debt	253,000	251,200
Wholesale lending-related commitments	0	0
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	1,089,200	1,007,800
Other	1,500	1,600
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	13,000	12,600
Beneficial interests issued by consolidated VIEs	0	0
Long-term debt	52,100	50,700
Wholesale lending-related commitments	$ 4,500	$ 4,400