Investment Securities (Contractual Maturity Distribution Of Debt Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Amortized Cost	$ 21,019	$ 22,045
Fair Value	18,295	$ 19,012
Debt securities
Available-for-sale, Within one year, Amortized Cost	504
Available-for-sale, After one year through five years, Amortized Cost	1,836
Available-for-sale, After five years through ten years, Amortized Cost	5,482
Available-for-sale, After ten years, Amortized Cost	13,197
Amortized Cost	21,019
Available-for-sale, Within one year, Fair Value	496
Available-for-sale, After one year through five years, Fair Value	1,717
Available-for-sale, After five years through ten years, Fair Value	5,001
Available-for-sale, After ten years, Fair Value	11,081
Fair Value	$ 18,295

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 320
-Section 50
-Paragraph 3A
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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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