Expenses - Restructuring Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Reserve [Roll Forward]
Beginning balance	$ 196	$ 198	$ 341
Accruals	(3)	133	110
Payments and Other Adjustments	(118)	(131)	(251)
Ending balance	74	196	198
Employee Related Costs
Restructuring Reserve [Roll Forward]
Beginning balance	190	190	303
Accruals	(32)	82	98
Payments and Other Adjustments	(89)	(78)	(209)
Ending balance	68	190	190
Real Estate Actions
Restructuring Reserve [Roll Forward]
Beginning balance	6	7	37
Accruals	29	51	12
Payments and Other Adjustments	(29)	(52)	(42)
Ending balance	6	6	7
Asset and Other Write-offs
Restructuring Reserve [Roll Forward]
Beginning balance	0	1	1
Accruals	0	0	0
Payments and Other Adjustments	0	(1)	0
Ending balance	0	0	1
State Street Beacon
Restructuring Reserve [Roll Forward]
Accruals	(1)	(4)	(2)
State Street Beacon | Employee Related Costs
Restructuring Reserve [Roll Forward]
Accruals	(1)	(4)	(2)
State Street Beacon | Real Estate Actions
Restructuring Reserve [Roll Forward]
Accruals	0	0	0
State Street Beacon | Asset and Other Write-offs
Restructuring Reserve [Roll Forward]
Accruals	$ 0	$ 0	$ 0