Short-Term Borrowings (Summary of Short-Term Borrowings) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Short-term Debt [Line Items]
Year-end balance	$ 903	$ 1,572
Securities sold, not yet purchased	254	61
Federal funds purchased and other short-term borrowings	903	1,572
Federal Home Loan Bank advances
Short-term Debt [Line Items]
Average amount outstanding	$ 0	$ 206
Average rate	0.00%	1.11%
Highest month-end balance	$ 0	$ 2,200
Year-end balance	$ 0	$ 0
Average rate on outstanding advances at year-end	0.00%	0.00%
Federal funds purchased and other short-term borrowings	$ 0	$ 0
Federal funds purchased
Short-term Debt [Line Items]
Other short-term borrowings, year-end balances	421	1,105
Security repurchase agreements
Short-term Debt [Line Items]
Other short-term borrowings, year-end balances	$ 228	$ 406

Amount of borrowings classified as other, maturing within one year or the normal operating cycle, if longer.

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Fair value of financial instruments sold short by a broker-dealer for their own account (proprietary securities) for trading or investment purposes determined by management based upon quoted prices of a financial instrument with similar characteristics or on a valuation technique or model.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.

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Short term debt weighted average rate.

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