Employee Benefit Plans - Postemployment Plan (Details) - Postemployment Retirement Benefits - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Net service cost	$ 7	$ 5	$ 13	$ 19
Interest cost	1	1	1	2
Amortization of prior service benefit	(1)	(1)	(1)	(2)
Amortization of actuarial gain	(1)	0	(2)	(1)
Net Benefit Cost	$ 6	$ 5	$ 11	$ 18