Employee Benefit Plans - Schedule of Amounts Recognized in Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Defined Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Other assets	$ 71	$ 80
Other liabilities	(10)	(12)
Net amount recognized as of December 31,	61	68
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Other assets	0	0
Other liabilities	(23)	(29)
Net amount recognized as of December 31,	$ (23)	$ (29)