Employee Benefit Plans - Postemployment Plan (Details) - Postemployment Retirement Benefits [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Net service cost	$ 5	$ 9	$ 19	$ 19
Interest cost	1	1	2	2
Amortization of prior service benefit	(1)	(1)	(2)	(2)
Amortization of actuarial gain	0	0	(1)	0
Net benefit cost	$ 5	$ 9	$ 18	$ 19