Investment Securities - Investment Securities, Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Unrealized credit losses on AFS securities	$ 0	$ 0	$ 0
Accrued interest on investment securities	4	5
Collateral pledged
Schedule of Investments [Line Items]
Pledged investment securities	$ 1,500	$ 200
Investments Benchmark \| Securities Concentration Risk \| U.S. Treasury and Government Agencies
Schedule of Investments [Line Items]
Concentration risk, percentage	82.00%

Debt Securities, Accrued Interest

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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Amount excluding accrued interest, of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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Amount of restricted investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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