Exit and Other Related Liabilities - Summary of Exit and Other Related Costs Recognized in Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		36 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023
TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	$ 16	$ 9	$ 56	$ 29	$ 384
Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	279		279
Compensation and benefits | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	9	6	23	23	307
Compensation and benefits | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	276		276
Occupancy and equipment | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	3	3	8	6	46
Occupancy and equipment | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	2		2
Depreciation and amortization | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					3
Professional services | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					1
Other | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	4		25		27
Other | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	1		1
Investor Services | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	16	7	44	22	303
Investor Services | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	204		204
Investor Services | Compensation and benefits | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	9	5	20	18	243
Investor Services | Compensation and benefits | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	202		202
Investor Services | Occupancy and equipment | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	3	2	6	4	37
Investor Services | Occupancy and equipment | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	1		1
Investor Services | Depreciation and amortization | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					2
Investor Services | Professional services | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					1
Investor Services | Other | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	4		18		20
Investor Services | Other | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	1		1
Investor Services | Employee Severance And Retention | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	9	5	20	18	243
Investor Services | Employee Severance And Retention | Compensation and benefits | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	9	5	20	18	243
Investor Services | Employee Severance And Retention | Occupancy and equipment | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	0	0	0	0
Investor Services | Employee Severance And Retention | Depreciation and amortization | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					0
Investor Services | Employee Severance And Retention | Professional services | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					0
Investor Services | Employee Severance And Retention | Other | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		0		0
Investor Services | Employee Compensation and Benefits | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	202		202
Investor Services | Employee Compensation and Benefits | Compensation and benefits | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	202		202
Investor Services | Employee Compensation and Benefits | Occupancy and equipment | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		0
Investor Services | Employee Compensation and Benefits | Other | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		0
Investor Services | Facility Exit Costs | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	7	2	24	4	60
Investor Services | Facility Exit Costs | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	2		2
Investor Services | Facility Exit Costs | Compensation and benefits | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	0	0	0	0
Investor Services | Facility Exit Costs | Compensation and benefits | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		0
Investor Services | Facility Exit Costs | Occupancy and equipment | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	3	2	6	4	37
Investor Services | Facility Exit Costs | Occupancy and equipment | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	1		1
Investor Services | Facility Exit Costs | Depreciation and amortization | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					2
Investor Services | Facility Exit Costs | Professional services | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					1
Investor Services | Facility Exit Costs | Other | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	4		18		20
Investor Services | Facility Exit Costs | Other | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	1		1
Advisor Services | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	2	12	7	81
Advisor Services | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	75		75
Advisor Services | Compensation and benefits | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	1	3	5	64
Advisor Services | Compensation and benefits | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	74		74
Advisor Services | Occupancy and equipment | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	1	2	2	9
Advisor Services | Occupancy and equipment | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	1		1
Advisor Services | Depreciation and amortization | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					1
Advisor Services | Professional services | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					0
Advisor Services | Other | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		7		7
Advisor Services | Other | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		0
Advisor Services | Employee Severance And Retention | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	1	3	5	64
Advisor Services | Employee Severance And Retention | Compensation and benefits | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	1	3	5	64
Advisor Services | Employee Severance And Retention | Occupancy and equipment | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	0	0	0	0
Advisor Services | Employee Severance And Retention | Depreciation and amortization | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					0
Advisor Services | Employee Severance And Retention | Professional services | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					0
Advisor Services | Employee Severance And Retention | Other | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		0		0
Advisor Services | Employee Compensation and Benefits | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	74		74
Advisor Services | Employee Compensation and Benefits | Compensation and benefits | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	74		74
Advisor Services | Employee Compensation and Benefits | Occupancy and equipment | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		0
Advisor Services | Employee Compensation and Benefits | Other | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		0
Advisor Services | Facility Exit Costs | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	1	9	2	17
Advisor Services | Facility Exit Costs | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	1		1
Advisor Services | Facility Exit Costs | Compensation and benefits | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	0	0	0	0
Advisor Services | Facility Exit Costs | Compensation and benefits | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		0
Advisor Services | Facility Exit Costs | Occupancy and equipment | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0	$ 1	2	$ 2	9
Advisor Services | Facility Exit Costs | Occupancy and equipment | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	1		1
Advisor Services | Facility Exit Costs | Depreciation and amortization | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					1
Advisor Services | Facility Exit Costs | Professional services | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense					0
Advisor Services | Facility Exit Costs | Other | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	0		7		$ 7
Advisor Services | Facility Exit Costs | Other | Other
Restructuring Cost and Reserve [Line Items]
Amounts recognized in expense	$ 0		$ 0