Investment Securities (Investment Income) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Taxable interest	$ 172	$ 141	$ 490	$ 390
Taxable dividends	4	3	10	8
Interest and dividends exempt from U.S. federal income tax	6	6	18	17
Interest and dividends on investment securities	198	157	562	437
Excludes other earning assets
Interest and dividends on investment securities	$ 182	$ 150	$ 518	$ 415

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

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=114873765&loc=SL114874048-224260

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