Regulatory Capital (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	$ 27,957	$ 27,028
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
Leverage ratio minimum	0.05
Capital conservation buffer, capital conserved, minimum	0.025
Stress capital buffer, minimum	2.50%
Banking regulation, global systemically important bank (G-SIB) surcharge	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	$ 11,245	$ 11,234
Retained earnings	27,957	27,028
Accumulated other comprehensive income (loss)	(2,354)	(3,711)
Treasury stock, at cost		(11,336)
Total	21,823	23,215
Goodwill and other intangible assets, net of associated deferred tax liabilities	(8,470)	(8,545)
Other adjustments	(382)	(123)
Common equity tier 1 capital	12,971	14,547
Preferred stock	1,976	1,976
Tier 1 capital	14,947	16,523
Qualifying subordinated long-term debt	1,870	1,376
Adjusted allowance for credit losses	0	0
Total capital	16,817	17,899
Credit risk	61,210	61,108
Operational risk	43,768	42,763
Market risk	2,475	1,488
Total risk-weighted assets	107,453	105,359
Adjusted quarterly average assets	$ 269,807	$ 275,678
Common equity tier 1 capital	12.10%	13.80%
Tier 1 capital	0.139	0.157
Total capital	0.157	0.170
Tier 1 leverage capital ratio, actual	0.055	0.060
Basel III Standardized Approach
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 11,245	$ 11,234
Retained earnings	27,957	27,028
Accumulated other comprehensive income (loss)	(2,354)	(3,711)
Total	21,823	23,215
Goodwill and other intangible assets, net of associated deferred tax liabilities	(8,470)	(8,545)
Other adjustments	(382)	(123)
Common equity tier 1 capital	12,971	14,547
Preferred stock	1,976	1,976
Tier 1 capital	14,947	16,523
Qualifying subordinated long-term debt	1,870	1,376
Adjusted allowance for credit losses	150	120
Total capital	16,967	18,019
Credit risk	109,228	105,739
Market risk	2,475	1,488
Total risk-weighted assets	111,703	107,227
Adjusted quarterly average assets	$ 269,807	$ 275,678
Common equity tier 1 capital	11.60%	13.60%
Tier 1 capital	0.134	0.154
Total capital	0.152	0.168
Tier 1 leverage capital ratio, actual	0.055	0.060
State Street Bank | Basel III Advanced Approaches
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 13,033	$ 13,033
Retained earnings	14,454	16,975
Accumulated other comprehensive income (loss)	(2,097)	(3,428)
Treasury stock, at cost	0	0
Total	25,390	26,580
Goodwill and other intangible assets, net of associated deferred tax liabilities	(8,208)	(8,288)
Other adjustments	(298)	(19)
Common equity tier 1 capital	16,884	18,273
Preferred stock	0	0
Tier 1 capital	16,884	18,273
Qualifying subordinated long-term debt	536	542
Adjusted allowance for credit losses	0	0
Total capital	17,420	18,815
Credit risk	54,942	54,675
Operational risk	42,297	42,325
Market risk	2,475	1,488
Total risk-weighted assets	99,714	98,488
Adjusted quarterly average assets	$ 266,818	$ 273,220
Common equity tier 1 capital	16.90%	18.60%
Tier 1 capital	0.169	0.186
Total capital	0.175	0.191
Tier 1 leverage capital ratio, actual	0.063	0.067
State Street Bank | Basel III Standardized Approach
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common stock and related surplus	$ 13,033	$ 13,033
Retained earnings	14,454	16,975
Accumulated other comprehensive income (loss)	(2,097)	(3,428)
Treasury stock, at cost	0	0
Total	25,390	26,580
Goodwill and other intangible assets, net of associated deferred tax liabilities	(8,208)	(8,288)
Other adjustments	(298)	(19)
Common equity tier 1 capital	16,884	18,273
Preferred stock	0	0
Tier 1 capital	16,884	18,273
Qualifying subordinated long-term debt	536	542
Adjusted allowance for credit losses	150	120
Total capital	17,570	18,935
Credit risk	107,067	104,184
Market risk	2,475	1,488
Total risk-weighted assets	109,542	105,672
Adjusted quarterly average assets	$ 266,818	$ 273,220
Common equity tier 1 capital	15.40%	17.30%
Tier 1 capital	0.154	0.173
Total capital	0.160	0.179
Tier 1 leverage capital ratio, actual	0.063	0.067