Acquisitions and Divestitures - Narrative (Details)		12 Months Ended
	Jul. 01, 2020 USD ($) office state newPreferredStockSeries shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($)	Jul. 17, 2020 USD ($) branch	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Common stock, shares issued (in shares) | shares	243,000,000	533,576,766	555,030,652
Number of new series of preferred stock | newPreferredStockSeries	3
Number of states | state	12
Purchase accounting gain		$ (1,000,000)	$ 533,000,000	$ 0
Goodwill		1,511,000,000	1,511,000,000	$ 1,433,000,000		$ 1,433,000,000
IBERIABANK (IBKC)
Business Acquisition [Line Items]
Number of offices | office	319
IBERIABANK (IBKC)
Business Acquisition [Line Items]
Purchase accounting gain	$ 531,000,000		533,000,000
Merger and integration expense		187,000,000	$ 155,000,000
IBERIABANK (IBKC) | IBERIABANK (IBKC)
Business Acquisition [Line Items]
Equity interest issued, value assigned	$ 2,500,000,000
Truist Bank Branches
Business Acquisition [Line Items]
Number of bank branches | branch					30
Goodwill		78,000,000			$ 78,000,000
TD Merger Agreement
Business Acquisition [Line Items]
Merger and integration expense		$ 0