Investment Securities (Investment Income) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Interest and dividends on investment securities	$ 238	$ 188
Excludes other earning assets
Taxable interest	217	174
Taxable dividends	3	4
Interest and dividends exempt from U.S. federal income tax	6	5
Interest and dividends on investment securities	$ 226	$ 183

Amount of operating dividend income on securities subject to state, federal and other income tax.

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Amount of operating dividend and interest income, including amortization and accretion of premiums and discounts, on securities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
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Interest income, including any amortization and accretion (as applicable) of discounts and premiums, derived from debt securities issued by municipal governments, local taxing districts and US state government agencies.

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Amount of operating interest income, including amortization and accretion of premiums and discounts, on securities subject to state, federal and other income tax.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
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