Long-Term Debt - Schedule of Long Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total long-term debt	$ 11,430	$ 11,497
Fair Value Hedges
Debt Instrument [Line Items]
Increase (decrease) in carrying value of long-term debt	$ (15)	105
Subordinated note | 3.10% subordinated notes due 2023
Debt Instrument [Line Items]
Interest rate on debt	3.10%
Subordinated note | 5.25% subordinated notes due 2018
Debt Instrument [Line Items]
Interest rate on debt	5.25%
Subordinated note | 5.30% subordinated notes due 2016
Debt Instrument [Line Items]
Interest rate on debt	5.30%
Senior notes | 3.55% notes due 2025
Debt Instrument [Line Items]
Interest rate on debt	3.55%
Senior notes | 2.55% notes due 2020
Debt Instrument [Line Items]
Interest rate on debt	2.55%
Senior notes | 3.70% notes due in 2023
Debt Instrument [Line Items]
Interest rate on debt	3.70%
Senior notes | 3.30% notes due 2024
Debt Instrument [Line Items]
Interest rate on debt	3.30%
Senior notes | 4.375% notes due 2021
Debt Instrument [Line Items]
Interest rate on debt	4.375%
Senior notes | 1.95% Notes Due 2021
Debt Instrument [Line Items]
Interest rate on debt	1.95%
Senior notes | 2.65% notes due 2026
Debt Instrument [Line Items]
Interest rate on debt	2.65%
Senior notes | 1.35% notes due 2018
Debt Instrument [Line Items]
Interest rate on debt	1.35%
Senior notes | 5.375% notes due 2017
Debt Instrument [Line Items]
Interest rate on debt	5.375%
Senior notes | 7.35% notes due 2026
Debt Instrument [Line Items]
Interest rate on debt	7.35%
Senior notes | 2.875% notes due 2016
Debt Instrument [Line Items]
Interest rate on debt	2.875%
Junior Subordinated Debt | 4.956% junior subordinated debentures due 2018
Debt Instrument [Line Items]
Interest rate on debt	4.956%
Statutory Business Trusts | Subordinated note | Floating-rate subordinated notes due to State Street Capital Trust IV in 2037
Debt Instrument [Line Items]
Long-term debt	$ 0	793
Statutory Business Trusts | Subordinated note | Floating-rate subordinated notes due to State Street Capital Trust I in 2028
Debt Instrument [Line Items]
Long-term debt	0	155
Parent Company and Non-banking Subsidiaries | Floating-rate notes due 2020
Debt Instrument [Line Items]
Long-term debt	499	498
Parent Company and Non-banking Subsidiaries | Subordinated note | Floating-rate subordinated notes due to State Street Capital Trust IV in 2037
Debt Instrument [Line Items]
Long-term debt	793	0
Parent Company and Non-banking Subsidiaries | Subordinated note | Floating-rate subordinated notes due to State Street Capital Trust I in 2028
Debt Instrument [Line Items]
Long-term debt	150	0
Parent Company and Non-banking Subsidiaries | Subordinated note | 3.10% subordinated notes due 2023
Debt Instrument [Line Items]
Long-term debt	987	993
Parent Company and Non-banking Subsidiaries | Senior notes | 3.55% notes due 2025
Debt Instrument [Line Items]
Long-term debt	1,293	1,301
Parent Company and Non-banking Subsidiaries | Senior notes | 2.55% notes due 2020
Debt Instrument [Line Items]
Long-term debt	1,192	1,194
Parent Company and Non-banking Subsidiaries | Senior notes | 3.70% notes due in 2023
Debt Instrument [Line Items]
Long-term debt	1,033	1,046
Parent Company and Non-banking Subsidiaries | Senior notes | 3.30% notes due 2024
Debt Instrument [Line Items]
Long-term debt	999	1,007
Parent Company and Non-banking Subsidiaries | Senior notes | 4.375% notes due 2021
Debt Instrument [Line Items]
Long-term debt	738	738
Parent Company and Non-banking Subsidiaries | Senior notes | 1.95% Notes Due 2021
Debt Instrument [Line Items]
Long-term debt	726	0
Parent Company and Non-banking Subsidiaries | Senior notes | 2.65% notes due 2026
Debt Instrument [Line Items]
Long-term debt	704	0
Parent Company and Non-banking Subsidiaries | Senior notes | 1.35% notes due 2018
Debt Instrument [Line Items]
Long-term debt	497	495
Parent Company and Non-banking Subsidiaries | Senior notes | 5.375% notes due 2017
Debt Instrument [Line Items]
Long-term debt	450	449
Parent Company and Non-banking Subsidiaries | Senior notes | 7.35% notes due 2026
Debt Instrument [Line Items]
Long-term debt	150	150
Parent Company and Non-banking Subsidiaries | Senior notes | 2.875% notes due 2016
Debt Instrument [Line Items]
Long-term debt	0	1,001
Parent Company and Non-banking Subsidiaries | Junior Subordinated Debt | 4.956% junior subordinated debentures due 2018
Debt Instrument [Line Items]
Long-term debt	511	519
Parent Company
Debt Instrument [Line Items]
Long-term debt	10,727	10,326
Parent Company | Capital Lease Obligations
Debt Instrument [Line Items]
Long-term capital leases	293	334
State Street Bank | Subordinated note | 5.25% subordinated notes due 2018
Debt Instrument [Line Items]
Long-term debt	415	424
State Street Bank | Subordinated note | 5.30% subordinated notes due 2016
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 400