Segment Information (Financial Information for Reportable Segments) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Net Revenues
Net interest revenue		$ 1,911	$ 1,572
Other		221	30
Total net revenues		4,715	2,617
Expenses Excluding Interest		2,755	1,570
Income before taxes on income		1,960	1,047
Asset management and administration fees [Member]
Net Revenues
Revenues from contracts with customers	[1]	1,016	827
Trading revenue [Member]
Net Revenues
Revenues from contracts with customers		1,216	188
Bank Deposit Account Fees [Member]
Net Revenues
Revenues from contracts with customers		351	0
Investor Services [Member]
Net Revenues
Net interest revenue		1,454	1,128
Other		178	20
Total net revenues		3,725	1,867
Expenses Excluding Interest		2,109	1,154
Income before taxes on income		1,616	713
Investor Services [Member] | Asset management and administration fees [Member]
Net Revenues
Revenues from contracts with customers		742	600
Investor Services [Member] | Trading revenue [Member]
Net Revenues
Revenues from contracts with customers		1,097	119
Investor Services [Member] | Bank Deposit Account Fees [Member]
Net Revenues
Revenues from contracts with customers		254	0
Advisor Services [Member]
Net Revenues
Net interest revenue		457	444
Other		43	10
Total net revenues		990	750
Expenses Excluding Interest		646	416
Income before taxes on income		344	334
Advisor Services [Member] | Asset management and administration fees [Member]
Net Revenues
Revenues from contracts with customers		274	227
Advisor Services [Member] | Trading revenue [Member]
Net Revenues
Revenues from contracts with customers		119	69
Advisor Services [Member] | Bank Deposit Account Fees [Member]
Net Revenues
Revenues from contracts with customers		$ 97	$ 0

[1] Includes fee waivers of $78 million for the first quarter of 2021. No fee waivers were recognized for the first quarter of 2020.