Income Taxes (Components of Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal
Current	$ (4)	$ (1)	$ (6)
Deferred	15	(6)	230
Total	11	(7)	224
Foreign
Current	(67)	(56)	(122)
Deferred	1	(20)	92
Total	(66)	(76)	(30)
State and other
Current	(2)	(2)	(2)
Deferred	(2)	(1)	1
Total	(4)	(3)	(1)
Current income tax (provision) benefit	(73)	(59)	(130)
Deferred income tax (provision) benefit	14	(27)	323
Total income tax (provision) benefit	$ (59)	$ (86)	$ 193