Other assets - Non-Readily Marketable Equity Securities (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Other Assets [Abstract]
Equity securities without readily determinable fair value, amount	$ 531		$ 531		$ 438
Equity securities without readily determinable fair value, upward price adjustment, annual amount	9	$ 18	35	$ 30
Equity securities without readily determinable fair value, downward price adjustment, annual amount	0	(1)	0	(1)
Equity securities without readily determinable fair value, net adjustment, annual amount	9	$ 17	35	$ 29
Equity securities without readily determinable fair value, upward price adjustment, cumulative amount	403		403
Equity securities without readily determinable fair value, downward price adjustment, cumulative amount	(102)		(102)
Equity securities without readily determinable fair value, net price adjustment, cumulative amount	$ 301		$ 301

Equity Securities without Readily Determinable Fair Value, Net Adjustment, Annual Amount

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Equity Securities without Readily Determinable Fair Value, Net Adjustment, Cumulative Amount

+ References

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- Definition

Amount of investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
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-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 320
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477268/942-320-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
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-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477268/942-320-50-2

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 321
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-Name Accounting Standards Codification
-Section 50
-Paragraph 3
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479536/321-10-50-3

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- Definition

Amount of loss from downward price adjustment on investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 321
-SubTopic 10
-Name Accounting Standards Codification
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-Paragraph 3
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-URI https://asc.fasb.org/1943274/2147479536/321-10-50-3

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- Definition

Amount of gain from upward price adjustment on investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 321
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-URI https://asc.fasb.org/1943274/2147479536/321-10-50-3

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Amount of cumulative gain from upward price adjustment on investment in equity security without readily determinable fair value.

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