Defined Severance Benefits - Schedule of components of net periodic benefit costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Retirement Benefits [Abstract]
Current service costs	$ 40	$ 35
Interest cost	4	3
Amortization of:
Prior service credit	0	1
Net actuarial loss	1	0
Net periodic benefit cost	$ 45	$ 39