Goodwill and intangible assets - Intangible Assets by Type (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Intangible Assets by Major Class [Line Items]
Gross carrying amount	$ 4,225	$ 4,329
Accumulated amortization	(1,291)	(1,338)
Net carrying amount	2,934	2,991	$ 2,964	$ 3,012
Securities Services
Intangible Assets by Major Class [Line Items]
Net carrying amount	207	230	179	194
Market and Wealth Services
Intangible Assets by Major Class [Line Items]
Net carrying amount	388	392	$ 400	$ 414
Finite-lived Intangible Assets
Intangible Assets by Major Class [Line Items]
Gross carrying amount	1,653	1,740
Accumulated amortization	(1,291)	(1,338)
Net carrying amount	$ 362	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	$ 739	747
Accumulated amortization	(532)	(518)
Net carrying amount	207	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	(297)	(356)
Net carrying amount	$ 17	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	(451)	(456)
Net carrying amount	$ 102	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	(11)	(8)
Net carrying amount	$ 36	39
Finite-lived Intangible Assets | Other | Weighted Average
Intangible Assets by Major Class [Line Items]
Remaining weighted- average amortization period	13 years
Indefinite-lived Intangible Assets
Intangible Assets by Major Class [Line Items]
Gross carrying amount	$ 2,572	2,589
Net carrying amount	2,572	2,589
Indefinite-lived Intangible Assets | Tradenames
Intangible Assets by Major Class [Line Items]
Gross carrying amount	1,290	1,294
Net carrying amount	1,290	1,294
Indefinite-lived Intangible Assets | Customer relationships
Intangible Assets by Major Class [Line Items]
Gross carrying amount	1,282	1,295
Net carrying amount	$ 1,282	$ 1,295