Income Taxes (Benefit (Provision) for Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended															6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	[1]	Sep. 30, 2019	Jun. 30, 2019	[1]	Mar. 31, 2019		Dec. 31, 2018	[1]	Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018		Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)																				$ (6)	$ (5)	$ (3)
Current Foreign																				(8)	(7)	(6)
Current State																				(5)	(5)	(2)
Total current																				(19)	(17)	(11)
Deferred Federal																				0	0	(18)
Deferred Foreign																				(2)	(2)	3
Total deferred						$ (1)								$ (1)		$ (1)	$ (1)	$ (2)	$ (2)	(2)	(2)	(15)
Benefit (provision) for income taxes	$ (6)		$ (5)	$ (4)		$ (6)	[1]	$ (5)		$ (5)		$ (5)		$ (4)	[1]	$ (10)	$ (9)	$ (15)	$ (13)	$ (21)	$ (19)	$ (26)

[1] The sum of quarterly information may not agree to year-to-date information due to rounding.