Intangible Assets (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization expense associated with finite lived intangible assets	$ 6	$ 6	$ 7
Minimum
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2018	0
2019	3
2020	3
2021	3
2022	3
Maximum
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2018	5
2019	5
2020	5
2021	5
2022	$ 5
Customer relationship intangibles | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives	7 years
Customer relationship intangibles | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives	19 years