Income Taxes Income Taxes (Schedule of Unrecognized Tax Benefits Roll Forward) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits	$ 44	$ 15	$ 14
Unrecognized tax benefits, additions based on current period tax positions	0	0	0
Unrecognized tax benefits, additions for prior period tax positions	11	29	3
Unrecognized tax benefits, reductions for prior period tax positions	(5)	0	(1)
Unrecognized tax benefits, reductions resulting from settlements	(2)	0	0
Unrecognized tax benefits, reduction resulting from expiration of statue of limitations	0	0	(1)
Unrecognized tax benefits	$ 48	$ 44	$ 15