Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income tax expense	$ 28	$ 8	$ 66	$ 64
Loss before income taxes	61	$ 159	206	$ 1,640
Unrecognized Tax Benefits	241		241
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 13		$ 13