Borrowings - Narrative (Details)		12 Months Ended
		Dec. 31, 2023 USD ($) debt_instrument	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($)
Line of Credit Facility [Line Items]
Debt outstanding		$ 26,128,000,000		$ 20,828,000,000
Other short-term borrowings	[1]	$ 6,553,000,000		$ 4,650,000,000
Weighted-average interest rate of short-term borrowings		5.57%		4.97%
Capacity of allowable commercial paper note issuance		$ 5,000,000,000
Commercial paper		0		$ 250,000,000
Secured Uncommitted Lines Of Credit
Line of Credit Facility [Line Items]
Other short-term borrowings		1,650,000,000
Senior Notes | TD Ameritrade Holding
Line of Credit Facility [Line Items]
Aggregate principal amount of debt			$ 2,000,000,000
Percentage of debt principal exchanged			90.00%
TD Ameritrade Holding | Senior Notes
Line of Credit Facility [Line Items]
Aggregate principal amount of debt			$ 2,200,000,000
Debt outstanding		$ 213,000,000
Number of debt instruments | debt_instrument		4
Secured Debt | Federal Home Loan Bank Advances
Line of Credit Facility [Line Items]
Borrowings outstanding		$ 26,400,000,000		$ 12,400,000,000
Weighted average interest rate		5.34%		4.88%
Line of credit facility, current borrowing capacity		$ 63,100,000,000		$ 68,600,000,000
Line of Credit | Uncommitted Lines Of Credit With External Banks
Line of Credit Facility [Line Items]
Other short-term borrowings		0		0
Total borrowing capacity		1,800,000,000
Line of Credit | Secured Uncommitted Lines Of Credit
Line of Credit Facility [Line Items]
Other short-term borrowings		950,000,000		0
Line of Credit | TD Ameritrade Clearing Inc
Line of Credit Facility [Line Items]
Other short-term borrowings		$ 700,000,000		0
Commercial paper | Maximum
Line of Credit Facility [Line Items]
Maturity term		270 days
Federal Reserve Bank Advances
Line of Credit Facility [Line Items]
Other short-term borrowings		$ 0		0
Total borrowing capacity		6,200,000,000		7,800,000,000
Federal Reserve Bank Term Funding Program (BTFP)
Line of Credit Facility [Line Items]
Other short-term borrowings		0
Total borrowing capacity		39,200,000,000
Repurchase agreements
Line of Credit Facility [Line Items]
Other short-term borrowings		$ 4,900,000,000		$ 4,400,000,000

[1] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.