Commitments, Guarantees and Contingencies - Narrative (Details) € in Millions, kr in Millions, $ in Millions					1 Months Ended
	Nov. 29, 2017 USD ($)	Nov. 29, 2017 DKK (kr)	Oct. 05, 2017 USD ($)	Oct. 05, 2017 DKK (kr)	Mar. 31, 2021 USD ($)	Jun. 30, 2024 EUR (€)	Jun. 30, 2024 USD ($)	Oct. 29, 2014 USD ($)	May 17, 2013 USD ($)
Common Class B | Viacom
Loss Contingencies
Amount of stock offered					$ 1,700
Convertible Preferred Stock Subject to Mandatory Redemption | Viacom
Loss Contingencies
Amount of stock offered					$ 1,000
Dividend rate					5.75%
Case Number 15/3637 and Case Number 15/4353 | Pending Litigation
Loss Contingencies
Withholding tax credit set-off						€ 124	$ 133
Case number B-803-18 (previously BS 99-6998/2017 | Pending Litigation
Loss Contingencies
Damages sought			$ 76	kr 529
Case number B-2073-16 | Pending Litigation
Loss Contingencies
Damages sought	$ 110	kr 767
IKB International S.A. in Liquidation, et al. v. Morgan Stanley, et al. | Pending Litigation
Loss Contingencies
Value of mortgage pass-through certificates								$ 116	$ 133