Income Taxes Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income tax (benefit) expense	$ (26)	$ (78)	$ (12)	$ (77)
Income (loss) from continuing operations before income tax benefit (expense)	$ (399)	$ (412)	$ (1,622)	$ 366
Effective income tax rate	6.50%	18.90%	0.70%	(21.00%)
Statutory federal income tax rate	21.00%	21.00%	21.00%	21.00%