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Significant Accounting Policies (Schedule Of Securities Segregated For Regulatory Purposes) (Details) - USD ($) $ in Millions		Jun. 30, 2024	Dec. 31, 2023
Marketable Securities [Line Items]
Securities - segregated for regulatory purposes		$ 28,318	$ 35,386
US Government Securities [Member]
Marketable Securities [Line Items]
Securities - segregated for regulatory purposes		6,439	5,684
Municipal Securities [Member]
Marketable Securities [Line Items]
Securities - segregated for regulatory purposes		57	70
Securities Purchased Under Agreement To Resell [Member]
Marketable Securities [Line Items]
Securities - segregated for regulatory purposes	[1]	$ 21,822	$ 29,632
[1] These balances are collateralized by U.S. government securities.

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Securities deposited in a special reserve account for the exclusive benefit of customers pursuant to SEC Regulations.

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