Employee Benefit Plans - Postemployment Plan (Details) - Postemployment Retirement Benefits - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Net service cost	$ 21	$ 5	$ 34	$ 24
Interest cost	0	0	1	2
Amortization of prior service benefit	0	0	(1)	(2)
Amortization of actuarial gain	(1)	(1)	(3)	(2)
Net benefit cost	$ 20	$ 4	$ 31	$ 22