Business Segments - Narrative (Details) $ in Trillions	6 Months Ended	12 Months Ended
	Sep. 30, 2020 employee	Dec. 31, 2020 USD ($) segment
Segment Reporting Information [Line Items]
Number of major reportable business segments | segment		4
Commercial Banking
Segment Reporting Information [Line Items]
Number of primary client segments | segment		3
Asset & Wealth Management
Segment Reporting Information [Line Items]
AWM client assets | $		$ 3.7
Business Unit, Support Staff, Number Of Employees | employee	(1,650)
Consumer & Community Banking
Segment Reporting Information [Line Items]
Business Unit, Support Staff, Number Of Employees | employee	1,650