Investment Securities (Investment Income) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Taxable interest	$ 858	$ 690	$ 534
Taxable dividends	14	14	12
Interest and dividends exempt from U.S. federal income tax	15	25	22
Interest and dividends on investment securities and other earning assets	955	788	599
Excludes other earning assets
Interest and dividends on investment securities and other earning assets	$ 887	$ 729	$ 568

Amount of operating dividend income on securities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.2)
-URI http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260

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

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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.

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