Employee Benefits (Details) - USD ($) $ in Millions	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2018	Jul. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Matching contributions amount	$ 7	$ 10		$ 15	$ 16
Tranche One
Defined Benefit Plan Disclosure [Line Items]
Employer percent match of contribution			100.00%
Percent match of gross pay			2.00%
Tranche Two
Defined Benefit Plan Disclosure [Line Items]
Employer percent match of contribution			50.00%
Percent match of gross pay			4.00%