Investments - Unrealized gains (losses) recognized in income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Gain (Loss) on Securities [Line Items]
Proceeds from Sale of Debt Securities, Available-for-sale	$ 7,048	$ 2,054	$ 10,766	$ 3,194
Consolidated Entity, excluding Affiliated Entity
Gain (Loss) on Securities [Line Items]
Debt Securities, Trading, Unrealized Gain (Loss)	(20)	(23)	(40)	40
Equity Securities, FV-NI, Unrealized Gain (Loss)	(7)	(7)	28	3
Related Party
Gain (Loss) on Securities [Line Items]
Debt Securities, Trading, Unrealized Gain (Loss)	(1)	(4)	(1)	(1)
Equity Securities, FV-NI, Unrealized Gain (Loss)	$ (1)	$ 4	$ (4)	$ (7)

Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-14

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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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
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Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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