Investments - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2025	Sep. 30, 2025
Investments, Debt and Equity Securities [Abstract]
Equity securities without readily determinable fair value, upward price adjustment, cumulative amount	$ 23	$ 23
Equity securities without readily determinable fair value, downward price adjustment, cumulative amount	$ 10	$ 10

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

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

Name:	us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant