Exit and Other Related Liabilities - Narrative (Details) $ in Millions	12 Months Ended			39 Months Ended
	Dec. 31, 2023 USD ($) clientTransitionGroup	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2023 USD ($)
TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Acquisition-related exit costs	$ 60	$ 34	$ 108	$ 388
Other Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Expected integration exit and other related costs	500			500
Acquisition-related exit costs	$ 495
TD Ameritrade, Inc
Restructuring Cost and Reserve [Line Items]
Number of integration client transition groups | clientTransitionGroup	4
Minimum | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Expected integration exit and other related costs	$ 500			500
Maximum | TD Ameritrade Integration
Restructuring Cost and Reserve [Line Items]
Expected integration exit and other related costs	$ 600			$ 600
Expected period of remaining costs to be incurred	12 months