Benefit Plans - Schedule of Amounts Expected to be Amortized from AOCI into Net Periodic Pension Cost During Next Fiscal Year (Details) - Heritage BBT $ in Millions	Dec. 31, 2019 USD ($)
Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 45
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year	(25)
Net amount expected to be amortized	70
Nonqualified Plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	25
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year	19
Net amount expected to be amortized	$ 6