Regulatory Matters (Regulatory Capital Ratios And Related Amounts) (Details) (USD $) In Millions, unless otherwise specified									12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 Statutory Minimum Requirement		Dec. 31, 2013 Standard Requirement Well Capitalized		Dec. 31, 2013 State Street	Dec. 31, 2012 State Street	Dec. 31, 2013 State Street Bank	Dec. 31, 2012 State Street Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 capital, ratio					4.00%	[1]	6.00%	[1]	17.30%	19.10%	16.40%	17.30%
Total capital, ratio					8.00%	[1]	10.00%	[1]	19.70%	20.60%	19.00%	19.10%
Tier 1 leverage ratio					4.00%	[1]	5.00%	[1]	6.90%	7.10%	6.40%	6.30%
Total shareholders’ equity	$ 20,378	$ 20,869	$ 19,398	$ 17,787					$ 20,378	$ 20,869	$ 19,755	$ 19,681
Trust preferred capital securities									950	950	0	0
Net unrealized loss on available-for-sale securities and cash flow hedges									107	(525)	112	(523)
Deferred tax liability, associated with acquisitions									653	699	638	680
Recognition of pension plan funded status									203	283	192	277
Goodwill	(6,036)	(5,977)	(5,645)						(6,036)	(5,977)	(5,740)	(5,679)
Other intangible assets									(2,360)	(2,539)	(2,239)	(2,392)
Tier 1 capital									13,895	13,760	12,718	12,044
Qualifying subordinated debt									1,918	1,219	1,936	1,223
Allowances for on- and off-balance sheet credit exposures									45	39	45	39
Unrealized gain on available-for-sale equity securities									(3)	(2)	0	0
Tier 2 capital									1,966	1,260	1,981	1,262
Deductions for investments in finance subsidiaries									(74)	(191)	0	0
Total capital									15,787	14,829	14,699	13,306
On-balance sheet									60,277	58,238	57,599	55,949
Off-balance sheet									18,587	13,155	18,598	13,144
Market-risk equivalents									1,262	519	1,262	445
Total									80,126	71,912	77,459	69,538
Adjusted quarterly average assets									$ 202,801	$ 192,817	$ 199,301	$ 189,780

[1] State Street Bank must comply with the regulatory guideline for “well capitalized” in order for the parent company to maintain its status as a financial holding company, including maintaining a minimum tier 1 risk-based capital ratio of 6%, a minimum total risk-based capital ratio of 10%, and a minimum tier 1 leverage ratio of 5%. The “well capitalized” guideline requires us to maintain a minimum tier 1 risk-based capital ratio of 6% and a minimum total risk-based capital ratio of 10%.