Investment Securities - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Accrued interest receivables on investment securities	$ 85		$ 85		$ 87
Impairment losses	12	$ 0	19	$ 0
Securities with a fair value, pledged as collateral	11,400		11,400		11,000
Investment Holdings [Line Items]
Unrealized losses	103		103		37
Non-rated Securities
Investment Holdings [Line Items]
Unrealized losses	$ 1		$ 1		$ 1

Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

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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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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of other-than-temporary impairment (OTTI) on investment in debt security, recognized in earnings.

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