Summary of Significant Accounting Policies and Basis of Presentation - Accounting Standards Not Yet Adopted (Details) - Scenario, Forecast - ASU 2016-02 $ in Millions	Jan. 01, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use assets expected to be recognized	$ 13
Subsequent Event
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities expected to be recognized	$ 13