Investment Securities (Investment Income) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Interest and dividends on investment securities	$ 267	$ 218	$ 752	$ 609
Excludes other earning assets
Taxable interest	246	196	692	556
Taxable dividends	5	4	12	12
Interest and dividends exempt from U.S. federal income tax	5	6	16	16
Interest and dividends on investment securities	$ 256	$ 206	$ 720	$ 584

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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