Regulatory Capital (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	$ 26,115	$ 25,238
Capital ratio: required common equity tier 1 capital	8.00%	8.00%
Capital ratio: required tier 1 capital	0.095	0.095
Capital ratio: required total capital	0.115	0.115
Tier 1 leverage capital ratio, minimum	0.040	0.040
Capital conservation buffer	0.025
Stress capital buffer	2.50%
Global systemically important bank	0.010
Countercyclical capital buffer	0
Basel III Advanced Approaches
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 11,261	$ 11,291
Retained earnings	26,115	25,238
Accumulated other comprehensive income (loss)	(3,687)	(1,133)
Treasury stock, at cost	(9,898)	(10,009)
Total	23,791	25,387
Goodwill and other intangible assets, net of associated deferred tax liabilities	(8,628)	(8,935)
Other adjustments	(281)	(505)
Common equity tier 1 capital	14,882	15,947
Preferred stock	1,976	1,976
Tier 1 capital	16,858	17,923
Qualifying subordinated long-term debt	1,381	1,588
Allowance for credit losses	0	0
Total capital	18,239	19,511
Credit risk	63,259	63,735
Operational risk	45,350	45,550
Market risk	1,838	2,113
Total risk-weighted assets	110,447	111,398
Adjusted quarterly average assets	$ 282,526	$ 293,567
Common equity tier 1 capital	13.50%	14.30%
Tier 1 capital	0.153	0.161
Total capital	0.165	0.175
Tier 1 leverage capital ratio, actual	0.060	0.061
Basel III Standardized Approach
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 11,261	$ 11,291
Retained earnings	26,115	25,238
Accumulated other comprehensive income (loss)	(3,687)	(1,133)
Treasury stock, at cost	(9,898)	(10,009)
Total	23,791	25,387
Goodwill and other intangible assets, net of associated deferred tax liabilities	(8,628)	(8,935)
Other adjustments	(281)	(505)
Common equity tier 1 capital	14,882	15,947
Preferred stock	1,976	1,976
Tier 1 capital	16,858	17,923
Qualifying subordinated long-term debt	1,381	1,588
Allowance for credit losses	113	108
Total capital	18,352	19,619
Credit risk	113,566	109,554
Market risk	1,838	2,113
Total risk-weighted assets	115,404	111,667
Adjusted quarterly average assets	$ 282,526	$ 293,567
Common equity tier 1 capital	12.90%	14.30%
Tier 1 capital	0.146	0.161
Total capital	0.159	0.176
Tier 1 leverage capital ratio, actual	0.060	0.061
State Street Bank | Basel III Advanced Approaches
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 13,033	$ 13,047
Retained earnings	17,025	15,700
Accumulated other comprehensive income (loss)	(3,410)	(926)
Treasury stock, at cost	0	0
Total	26,648	27,821
Goodwill and other intangible assets, net of associated deferred tax liabilities	(8,370)	(8,667)
Other adjustments	(104)	(309)
Common equity tier 1 capital	18,174	18,845
Preferred stock	0	0
Tier 1 capital	18,174	18,845
Qualifying subordinated long-term debt	545	752
Allowance for credit losses	0	0
Total capital	18,719	19,597
Credit risk	56,041	57,405
Operational risk	42,700	42,813
Market risk	1,838	2,113
Total risk-weighted assets	100,579	102,331
Adjusted quarterly average assets	$ 279,665	$ 290,403
Common equity tier 1 capital	18.10%	18.40%
Tier 1 capital	0.181	0.184
Total capital	0.186	0.192
Tier 1 leverage capital ratio, actual	0.065	0.065
State Street Bank | Basel III Standardized Approach
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 13,033	$ 13,047
Retained earnings	17,025	15,700
Accumulated other comprehensive income (loss)	(3,410)	(926)
Treasury stock, at cost	0	0
Total	26,648	27,821
Goodwill and other intangible assets, net of associated deferred tax liabilities	(8,370)	(8,667)
Other adjustments	(104)	(309)
Common equity tier 1 capital	18,174	18,845
Preferred stock	0	0
Tier 1 capital	18,174	18,845
Qualifying subordinated long-term debt	545	752
Allowance for credit losses	113	108
Total capital	18,832	19,705
Credit risk	110,950	106,405
Market risk	1,838	2,113
Total risk-weighted assets	112,788	108,518
Adjusted quarterly average assets	$ 279,665	$ 290,403
Common equity tier 1 capital	16.10%	17.40%
Tier 1 capital	0.161	0.174
Total capital	0.167	0.182
Tier 1 leverage capital ratio, actual	0.065	0.065