Employment Benefit Plans Savings Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	3.00%
Defined Contribution Plan, Cost	$ 1	$ 1	$ 1
Minimum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	100.00%
Maximum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	50.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	2.00%