Expenses - Restructuring Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restructuring Reserve [Roll Forward]
Beginning balance	$ 88	$ 74	$ 196
Net repositioning benefit	203	78	(3)
Payments and Other Adjustments	(83)	(64)	(118)
Ending balance	208	88	74
Employee Related Costs
Restructuring Reserve [Roll Forward]
Beginning balance	83	68	190
Net repositioning benefit	182	58	(32)
Payments and Other Adjustments	(58)	(43)	(89)
Ending balance	207	83	68
Real Estate Actions
Restructuring Reserve [Roll Forward]
Beginning balance	5	6	6
Net repositioning benefit	21	20	29
Payments and Other Adjustments	(25)	(21)	(29)
Ending balance	$ 1	$ 5	6
State Street Beacon
Restructuring Reserve [Roll Forward]
Net repositioning benefit			(1)
State Street Beacon | Employee Related Costs
Restructuring Reserve [Roll Forward]
Net repositioning benefit			(1)
State Street Beacon | Real Estate Actions
Restructuring Reserve [Roll Forward]
Net repositioning benefit			$ 0