Benefit Plans - Schedule of Pre-tax Amounts Recognized in AOCI (Inactive Plan) - (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Heritage BBT | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 45
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	1,360	$ 1,489
Net actuarial loss	(1,246)	(1,349)
Heritage BBT | Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	25
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	121	41
Net actuarial loss	(217)	$ (156)
SunTrust Banks Inc. | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	28
Net actuarial loss	28
SunTrust Banks Inc. | Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	0
Net actuarial loss	$ 0