Goodwill and intangible assets - Intangible Assets by Type (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Intangible Assets by Major Class [Line Items]
Gross carrying amount	$ 4,208	$ 4,329
Accumulated amortization	(1,306)	(1,338)
Net carrying amount	2,902	2,991	$ 2,941	$ 3,012
Securities Services
Intangible Assets by Major Class [Line Items]
Net carrying amount	197	230	170	194
Market and Wealth Services
Intangible Assets by Major Class [Line Items]
Net carrying amount	386	392	$ 397	$ 414
Finite-lived Intangible Assets
Intangible Assets by Major Class [Line Items]
Gross carrying amount	1,647	1,740
Accumulated amortization	(1,306)	(1,338)
Net carrying amount	$ 341	402
Finite-lived Intangible Assets | Weighted Average
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	10 years
Finite-lived Intangible Assets | Customer contracts—Investment Services | Securities Services
Intangible Assets by Major Class [Line Items]
Gross carrying amount	$ 733	747
Accumulated amortization	(538)	(518)
Net carrying amount	195	229
Finite-lived Intangible Assets | Customer contracts—Investment Services | Market and Wealth Services
Intangible Assets by Major Class [Line Items]
Gross carrying amount	314	378
Accumulated amortization	(299)	(356)
Net carrying amount	$ 15	22
Finite-lived Intangible Assets | Customer contracts—Investment Services | Weighted Average | Securities Services
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	11 years
Finite-lived Intangible Assets | Customer contracts—Investment Services | Weighted Average | Market and Wealth Services
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	4 years
Finite-lived Intangible Assets | Customer relationships
Intangible Assets by Major Class [Line Items]
Gross carrying amount	$ 553	568
Accumulated amortization	(456)	(456)
Net carrying amount	$ 97	112
Finite-lived Intangible Assets | Customer relationships | Weighted Average
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	9 years
Finite-lived Intangible Assets | Other
Intangible Assets by Major Class [Line Items]
Gross carrying amount	$ 47	47
Accumulated amortization	(13)	(8)
Net carrying amount	$ 34	39
Finite-lived Intangible Assets | Other | Weighted Average
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	14 years
Indefinite-lived Intangible Assets
Intangible Assets by Major Class [Line Items]
Gross carrying amount	$ 2,561	2,589
Net carrying amount	2,561	2,589
Indefinite-lived Intangible Assets | Tradenames
Intangible Assets by Major Class [Line Items]
Gross carrying amount	1,288	1,294
Net carrying amount	1,288	1,294
Indefinite-lived Intangible Assets | Customer relationships
Intangible Assets by Major Class [Line Items]
Gross carrying amount	1,273	1,295
Net carrying amount	$ 1,273	$ 1,295