Loans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, Unpaid principal balance	$ 19	$ 19
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest Rate On Term Loan		6.51%
Loan Maturity Date	Jun. 30, 2026
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest Rate On Term Loan	7.35%	8.60%
Loan Maturity Date	Dec. 15, 2046