Goodwill and intangible assets - Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Goodwill [Roll Forward]
Beginning balance	$ 17,386	$ 17,350
Foreign currency translation	(146)	17
Other	0
Ending balance	17,240	17,367
Investment Services
Goodwill [Roll Forward]
Beginning balance	8,332	8,333
Foreign currency translation	(43)	(5)
Other	47
Ending balance	8,336	8,328
Investment Management
Goodwill [Roll Forward]
Beginning balance	9,007	8,970
Foreign currency translation	(103)	22
Other	0
Ending balance	8,904	8,992
Other
Goodwill [Roll Forward]
Beginning balance	47	47
Foreign currency translation	0	0
Other	(47)
Ending balance	$ 0	$ 47