Goodwill and Other Intangible Assets - Summary Of Gross Goodwill And Accumulated Impairment Losses And Write-Offs Detailed By Reportable Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, Beginning balance	$ 1,511	$ 1,433	$ 1,433
Additions	0	78	0
Goodwill, Ending balance	1,511	1,511	1,433
Regional Banking
Goodwill [Roll Forward]
Goodwill, Beginning balance	880	802	802
Additions	0	78	0
Goodwill, Ending balance	880	880	802
Specialty Banking
Goodwill [Roll Forward]
Goodwill, Beginning balance	631	631	631
Additions	0	0	0
Goodwill, Ending balance	$ 631	$ 631	$ 631