Expenses - Restructuring Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Beginning balance	$ 23	$ 69	$ 106
Accruals for State Street Beacon	142
Payments and Other Adjustments	(107)	(51)	(112)
Ending balance	56	23	69
Employee Related Costs
Restructuring Reserve [Roll Forward]
Beginning balance	9	39	52
Payments and Other Adjustments	(64)	(25)	(45)
Ending balance	37	9	39
Real Estate Consolidation
Restructuring Reserve [Roll Forward]
Beginning balance	11	23	47
Payments and Other Adjustments	(12)	(9)	(46)
Ending balance	17	11	23
Asset and Other Write-offs
Restructuring Reserve [Roll Forward]
Beginning balance	3	7	7
Payments and Other Adjustments	(31)	(17)	(21)
Ending balance	2	3	7
State Street Beacon | Employee Related Costs
Restructuring Reserve [Roll Forward]
Accruals for State Street Beacon	94
State Street Beacon | Real Estate Consolidation
Restructuring Reserve [Roll Forward]
Accruals for State Street Beacon	18
State Street Beacon | Asset and Other Write-offs
Restructuring Reserve [Roll Forward]
Accruals for State Street Beacon	30
Ops and IT
Restructuring Reserve [Roll Forward]
Accruals for State Street Beacon	(2)	5	75
Ops and IT | Employee Related Costs
Restructuring Reserve [Roll Forward]
Accruals for State Street Beacon	(2)	(5)	32
Ops and IT | Real Estate Consolidation
Restructuring Reserve [Roll Forward]
Accruals for State Street Beacon	0	(3)	22
Ops and IT | Asset and Other Write-offs
Restructuring Reserve [Roll Forward]
Accruals for State Street Beacon	$ 0	$ 13	$ 21