Sale of Certain Private Banking Client Relationships (Details) - USD ($) $ in Millions	12 Months Ended		25 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Dec. 31, 2019	Aug. 31, 2017
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Client deposit	$ 110,955	$ 118,702		$ 119,693
Client investments transferred			$ 1,500
Client deposits transferred			800
Contingent consideration received			$ 12
Portion of Latin America Portfolio [Member] | PB [Member]
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Client investments					$ 3,500
Client deposit					1,700
Fee, as percent of assets transferred during first 2 years of agreement (percent)			0.50%
Other assets [Member]
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Contingent consideration receivable	12				$ 15
Other Income (Loss) [Member]
Risks Inherent in Servicing Assets and Servicing Liabilities [Line Items]
Pre-tax gain (loss) on sale	$ (3)	$ 8