Clearing Operations (Schedule of Clearing Member Default Fund Contributions And Margin Deposits) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Clearing Operations [Line Items]
Default fund contributions	$ 869
Margin deposits	13,033
Total	13,902
Cash Contributions
Clearing Operations [Line Items]
Default fund contributions	736
Margin deposits	5,834
Total	6,570	$ 5,911
Non-Cash Contributions
Clearing Operations [Line Items]
Default fund contributions	133
Margin deposits	7,199
Total	$ 7,332