Unaudited Consolidated Statements of Cash Flows - Supplemental Information - USD ($) $ in Millions	Jun. 30, 2019		Dec. 31, 2018	Jun. 30, 2018		Dec. 31, 2017
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 245		$ 242	$ 185
Restricted cash	304		319	310
Total cash, cash equivalents, and restricted cash	$ 549	[1]	$ 561	$ 495	[1]	$ 575

[1] The following table provides a reconciliation of cash, cash equivalents and restricted cash to amount reported within the consolidated balance sheets. Cash and cash equivalents of $245 and $185, Restricted cash of $304 and $310, and Total cash, cash equivalents, and restricted cash of $549 and $495, as of June 30, 2019 and June 30, 2018, respectively