Segment Information (Financial Information for Reportable Segments) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Net Revenues
Net interest revenue	[1]									$ 6,113		$ 6,516		$ 5,823
Other revenue	[1]									332		242		178
Total net revenues		$ 4,176	$ 2,448	$ 2,450	$ 2,617	$ 2,606	$ 2,711	$ 2,681	$ 2,723	11,691	[1]	10,721	[1]	10,132	[1]
Total expenses excluding interest		$ 2,700	$ 1,559	$ 1,562	$ 1,570	$ 1,494	$ 1,475	$ 1,445	$ 1,459	7,391	[1]	5,873	[1]	5,570	[1]
Income before taxes on income	[1]									4,300		4,848		4,562
Capital expenditures										741		753		576
Depreciation and amortization										414		322		277
Amortization of acquired intangible assets	[1]									190		27		29
Investor Services [Member]
Net Revenues
Net interest revenue										4,391		4,685		4,341
Other revenue										262		146		116
Total net revenues										8,608		7,623		7,321
Total expenses excluding interest										5,529		4,284		4,145
Income before taxes on income										3,079		3,339		3,176
Capital expenditures										535		507		390
Depreciation and amortization										288		216		158
Amortization of acquired intangible assets										149		26		28
Advisor Services [Member]
Net Revenues
Net interest revenue										1,722		1,831		1,482
Other revenue										70		96		62
Total net revenues										3,083		3,098		2,811
Total expenses excluding interest										1,862		1,589		1,425
Income before taxes on income										1,221		1,509		1,386
Capital expenditures										206		246		186
Depreciation and amortization										126		106		119
Amortization of acquired intangible assets										41		1		1
Asset Management and administration fees [Member]
Net Revenues
Revenues from contracts with customers	[1],[2]									3,475		3,211		3,229
Asset Management and administration fees [Member] | Investor Services [Member]
Net Revenues
Revenues from contracts with customers										2,544		2,289		2,260
Asset Management and administration fees [Member] | Advisor Services [Member]
Net Revenues
Revenues from contracts with customers										931		922		969
Trading revenue [Member]
Net Revenues
Revenues from contracts with customers	[1]									1,416		752		902
Trading revenue [Member] | Investor Services [Member]
Net Revenues
Revenues from contracts with customers										1,156		503		604
Trading revenue [Member] | Advisor Services [Member]
Net Revenues
Revenues from contracts with customers										260		249		298
Bank Deposit Account Fees [Member]
Net Revenues
Revenues from contracts with customers	[1]									355		0		0
Bank Deposit Account Fees [Member] | Investor Services [Member]
Net Revenues
Revenues from contracts with customers										255		0		0
Bank Deposit Account Fees [Member] | Advisor Services [Member]
Net Revenues
Revenues from contracts with customers										$ 100		$ 0		$ 0

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

[2] Includes fee waivers of $127 million for the year ended December 31, 2020.