Fair Value - Net Losses and Gains Recognized for Investments in Equity Securities (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Trading Securities And Other Trading Assets [Line Items]
Net gains and (losses) recognized during the year on equity securities	$ 11	$ (28)	$ 20
Available-for-sale Securities
Schedule Of Trading Securities And Other Trading Assets [Line Items]
Net gains and (losses) recognized during the year on equity securities	(5)	(2)	13
Held-to-maturity Securities
Schedule Of Trading Securities And Other Trading Assets [Line Items]
Unrealized gains and (losses) recognized during the year on equity securities held at the end of year	$ 16	$ (26)	$ 7

Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(3)(d)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 321
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479536/321-10-50-4

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Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(3)(d)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 321
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479536/321-10-50-4

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+ References

No definition available.

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