Fair Value Option - Changes in Fair Value Under the Fair Value Option (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Federal funds sold and securities purchased under resale agreements
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	$ 161	$ 144	$ 300
Federal funds sold and securities purchased under resale agreements | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	161	144	300
Federal funds sold and securities purchased under resale agreements | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0
Securities borrowed
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(3)	347	164
Securities borrowed | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(3)	347	164
Securities borrowed | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0
Trading assets: Debt and equity instruments, excluding loans
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	3,020	7,205	3,656
Trading assets: Debt and equity instruments, excluding loans | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	3,020	7,205	3,656
Trading assets: Debt and equity instruments, excluding loans | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0
Loans reported as trading assets: Changes in instrument-specific credit risk
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(9)	346	248
Loans reported as trading assets: Changes in instrument-specific credit risk | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(9)	346	248
Loans reported as trading assets: Changes in instrument-specific credit risk | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0
Loans reported as trading assets: Other changes in fair value
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	34	19	8
Loans reported as trading assets: Other changes in fair value | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	14	9	3
Loans reported as trading assets: Other changes in fair value | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	20	10	5
Loans: Changes in instrument-specific credit risk
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	541	511	318
Loans: Changes in instrument-specific credit risk | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	541	517	322
Loans: Changes in instrument-specific credit risk | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	(6)	(4)
Loans: Other changes in fair value
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	1,245	446	643
Loans: Other changes in fair value | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	463	75	427
Loans: Other changes in fair value | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	782	371	216
Other assets
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	44	63	278
Other assets | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	47	63	282
Other assets | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(3)	0	(4)
Deposits
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(1,839)	(3,398)	(2,582)
Deposits | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(1,839)	(3,398)	(2,582)
Deposits | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0
Federal funds purchased and securities loaned or sold under repurchase agreements
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(26)	(12)	(121)
Federal funds purchased and securities loaned or sold under repurchase agreements | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(26)	(12)	(121)
Federal funds purchased and securities loaned or sold under repurchase agreements | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0
Short-term borrowings
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(1,405)	(922)	(567)
Short-term borrowings | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(1,405)	(922)	(567)
Short-term borrowings | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0
Trading liabilities
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(31)	(1)	(24)
Trading liabilities | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(31)	(1)	(24)
Trading liabilities | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0
Other liabilities
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(5)	(11)	(16)
Other liabilities | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(5)	(11)	(16)
Other liabilities | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	0	0	0
Long-term debt
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(7,116)	(2,717)	(5,953)
Long-term debt | Principal transactions
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	(7,112)	(2,711)	(5,875)
Long-term debt | All other income
Changes in fair value under the fair value option election
Fair value option, changes in fair value gain (loss)	$ (4)	$ (6)	$ (78)