Investment Securities (Details 1) $ in Millions	Dec. 31, 2020 security	Dec. 31, 2019 USD ($) security
Investments, Debt and Equity Securities [Abstract]
Number of available-for-sale debt securities with gross unrealized losses \| security	0	5
Available-for-sale investment securities with gross unrealized losses and length of time
Estimated Fair Value, Less than 12 months		$ 18
Estimated Fair Value, 12 months or more		324
Available-for-sale investment securities with gross unrealized losses
Gross Unrealized Losses, Less than 12 months		(1)
Gross Unrealized Losses, 12 months or more		(1)
State and municipal obligations [Member]
Available-for-sale investment securities with gross unrealized losses and length of time
Estimated Fair Value, Less than 12 months		18
Estimated Fair Value, 12 months or more		0
Available-for-sale investment securities with gross unrealized losses
Gross Unrealized Losses, Less than 12 months		(1)
Gross Unrealized Losses, 12 months or more		0
US government treasury obligations [Member]
Available-for-sale investment securities with gross unrealized losses and length of time
Estimated Fair Value, Less than 12 months		0
Estimated Fair Value, 12 months or more		324
Available-for-sale investment securities with gross unrealized losses
Gross Unrealized Losses, Less than 12 months		0
Gross Unrealized Losses, 12 months or more		$ (1)

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Debt Securities, Available-for-sale, Unrealized Loss Position1

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
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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 continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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 continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Number of investments in debt securities 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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