Goodwill And Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets [Abstract]
Amortization expense	$ 29	$ 18	$ 18
Amortization expense, 2019	34
Amortization expense, 2020	34
Amortization expense, 2021	31
Amortization expense, 2022	28
Amortization expense, 2023	$ 20