Exit and Other Related Liabilities (Summary of the Cumulative Acquisition-Related Exit Costs) (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	$ 9	$ 99
Cumulative exit and other related costs incurred to date	285	285
Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	7	79
Cumulative exit and other related costs incurred to date	255	255
Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	2	18
Cumulative exit and other related costs incurred to date	25	25
Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative exit and other related costs incurred to date	3	3
Professional services [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		1
Cumulative exit and other related costs incurred to date	1	1
Other [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		1
Cumulative exit and other related costs incurred to date	1	1
Investor Services [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	8	80
Cumulative exit and other related costs incurred to date	226	226
Investor Services [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	6	63
Cumulative exit and other related costs incurred to date	201	201
Investor Services [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	2	15
Cumulative exit and other related costs incurred to date	21	21
Investor Services [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative exit and other related costs incurred to date	2	2
Investor Services [Member] | Professional services [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		1
Cumulative exit and other related costs incurred to date	1	1
Investor Services [Member] | Other [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		1
Cumulative exit and other related costs incurred to date	1	1
Investor Services [Member] | Employee Compensation and Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	6	63
Cumulative exit and other related costs incurred to date	201	201
Investor Services [Member] | Employee Compensation and Benefits [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	6	63
Cumulative exit and other related costs incurred to date	201	201
Investor Services [Member] | Employee Compensation and Benefits [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	0	0
Cumulative exit and other related costs incurred to date	0	0
Investor Services [Member] | Employee Compensation and Benefits [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative exit and other related costs incurred to date	0	0
Investor Services [Member] | Employee Compensation and Benefits [Member] | Professional services [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		0
Cumulative exit and other related costs incurred to date	0	0
Investor Services [Member] | Employee Compensation and Benefits [Member] | Other [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		0
Cumulative exit and other related costs incurred to date	0	0
Investor Services [Member] | Facility Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	2	17
Cumulative exit and other related costs incurred to date	25	25
Investor Services [Member] | Facility Exit Costs [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	0	0
Cumulative exit and other related costs incurred to date	0	0
Investor Services [Member] | Facility Exit Costs [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	2	15
Cumulative exit and other related costs incurred to date	21	21
Investor Services [Member] | Facility Exit Costs [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative exit and other related costs incurred to date	2	2
Investor Services [Member] | Facility Exit Costs [Member] | Professional services [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		1
Cumulative exit and other related costs incurred to date	1	1
Investor Services [Member] | Facility Exit Costs [Member] | Other [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		1
Cumulative exit and other related costs incurred to date	1	1
Advisor Services [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	1	19
Cumulative exit and other related costs incurred to date	59	59
Advisor Services [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	1	16
Cumulative exit and other related costs incurred to date	54	54
Advisor Services [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	0	3
Cumulative exit and other related costs incurred to date	4	4
Advisor Services [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative exit and other related costs incurred to date	1	1
Advisor Services [Member] | Professional services [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		0
Cumulative exit and other related costs incurred to date	0	0
Advisor Services [Member] | Other [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		0
Cumulative exit and other related costs incurred to date	0	0
Advisor Services [Member] | Employee Compensation and Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	1	16
Cumulative exit and other related costs incurred to date	54	54
Advisor Services [Member] | Employee Compensation and Benefits [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	1	16
Cumulative exit and other related costs incurred to date	54	54
Advisor Services [Member] | Employee Compensation and Benefits [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	0	0
Cumulative exit and other related costs incurred to date	0	0
Advisor Services [Member] | Employee Compensation and Benefits [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative exit and other related costs incurred to date	0	0
Advisor Services [Member] | Employee Compensation and Benefits [Member] | Professional services [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		0
Cumulative exit and other related costs incurred to date	0	0
Advisor Services [Member] | Employee Compensation and Benefits [Member] | Other [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		0
Cumulative exit and other related costs incurred to date	0	0
Advisor Services [Member] | Facility Exit Costs [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	0	3
Cumulative exit and other related costs incurred to date	5	5
Advisor Services [Member] | Facility Exit Costs [Member] | Compensation and benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	0	0
Cumulative exit and other related costs incurred to date	0	0
Advisor Services [Member] | Facility Exit Costs [Member] | Occupancy and equipment [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period	0	3
Cumulative exit and other related costs incurred to date	4	4
Advisor Services [Member] | Facility Exit Costs [Member] | Depreciation and amortization [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative exit and other related costs incurred to date	1	1
Advisor Services [Member] | Facility Exit Costs [Member] | Professional services [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		0
Cumulative exit and other related costs incurred to date	0	0
Advisor Services [Member] | Facility Exit Costs [Member] | Other [Member]
Restructuring Cost and Reserve [Line Items]
Exit and other related costs incurred in period		0
Cumulative exit and other related costs incurred to date	$ 0	$ 0