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Significant Accounting Policies (Schedule Of Securities Segregated For Regulatory Purposes) (Details) - USD ($) $ in Millions | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Marketable Securities [Line Items] |  |  |
Securities - segregated for regulatory purposes |  | $ 29,394 | $ 27,846
US And Foreign Government Securities [Member] |  |  |
Marketable Securities [Line Items] |  |  |
Securities - segregated for regulatory purposes |  | 6,361 | 6,460
Municipal Securities [Member] |  |  |
Marketable Securities [Line Items] |  |  |
Securities - segregated for regulatory purposes |  | 33 | 33
Securities Purchased Under Agreement To Resell [Member] |  |  |
Marketable Securities [Line Items] |  |  |
Securities - segregated for regulatory purposes | [1] | 22,860 | $ 21,353
Securities Borrowed [Member] |  |  |
Marketable Securities [Line Items] |  |  |
Securities - segregated for regulatory purposes | [1] | $ 140 |
[1] | These balances are collateralized by U.S. government securities.

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