Employee Benefit Plans - Postemployment Plan (Details) - Postemployment Retirement Benefits [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Net service cost	$ 5	$ 4	$ 24	$ 23
Interest cost	0	0	2	2
Amortization of prior service benefit	0	(2)	(2)	(4)
Amortization of actuarial gain	(1)	0	(2)	0
Net benefit cost	$ 4	$ 2	$ 22	$ 21