Exit and Other Related Liabilities (Summary of the Cumulative Acquisition-Related Exit Costs) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	$ 186
Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	176
Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	7
Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	3
Investor Services [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	146
Investor Services [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	138
Investor Services [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	6
Investor Services [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	2
Investor Services [Member] | Employee Compensation and Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	138
Investor Services [Member] | Employee Compensation and Benefits [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	138
Investor Services [Member] | Employee Compensation and Benefits [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	0
Investor Services [Member] | Employee Compensation and Benefits [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	0
Investor Services [Member] | Facility Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	8
Investor Services [Member] | Facility Exit Costs [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	0
Investor Services [Member] | Facility Exit Costs [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	6
Investor Services [Member] | Facility Exit Costs [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	2
Advisor Services [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	40
Advisor Services [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	38
Advisor Services [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	1
Advisor Services [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	1
Advisor Services [Member] | Employee Compensation and Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	38
Advisor Services [Member] | Employee Compensation and Benefits [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	38
Advisor Services [Member] | Employee Compensation and Benefits [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	0
Advisor Services [Member] | Employee Compensation and Benefits [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	0
Advisor Services [Member] | Facility Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	2
Advisor Services [Member] | Facility Exit Costs [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	0
Advisor Services [Member] | Facility Exit Costs [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	1
Advisor Services [Member] | Facility Exit Costs [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative amount of acquisition-related exit costs incurred	$ 1