Benefit Plans - Summary of the Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Net periodic pension cost:
Service cost(1)	[1]	$ 96	$ 93
Interest cost		108	111
Estimated return on plan assets		(244)	(228)
Net amortization and other		1	20
Net periodic benefit cost (income)		(39)	(4)
IH
Net periodic pension cost:
Service cost(1)		$ 7	$ 7

[1] Includes $7 million for the three months ended March 31, 2024 and 2023 of service cost reported in net income from discontinued operations for the qualified defined benefit pension plan for employees of TIH. Following the sale of TIH, Truist will (i) no longer recognize the service costs for TIH employees, (ii) retain the related postretirement benefit obligation for TIH employees, and (iii) remeasure the postretirement benefit obligation of the plan.