Summary of Significant Accounting Policies (Schedule of Cash and Cash equivalents) (Details) - USD ($) $ in Millions		Dec. 31, 2021		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents		$ 30		$ 5	$ 4	$ 377
Restricted cash and equivalents		24	[1]	0	0	0
Cash, restricted cash and equivalents shown in the Consolidated Statements of Cash Flows	[2]	$ 54		$ 5	$ 4	$ 377

[1] At December 31 2020, 2019 and 2018 there were no restricted cash and equivalent balances.

[2] Includes $24 million of restricted cash for the year ended December 31, 2021. For the years ended December 31, 2020 and 2019 there were no restricted cash and equivalent balances.