Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets
Deferred revenue	$ 256
Net operating loss carry forwards	3,633
Property, plant and equipment	63
Other	282
Gross deferred tax assets	4,234
Less valuation allowance	(942)
Net deferred tax assets	3,292
Deferred tax liabilities
Deferred revenue	(44)
Property, plant and equipment	(689)
Intangible assets	(2,329)
Other	(16)
Gross deferred tax liabilities	(3,078)
Net deferred tax assets	$ 214
Predecessor
Deferred tax assets
Deferred revenue		$ 364
Net operating loss carry forwards		4,550
Property, plant and equipment		95
Other		471
Gross deferred tax assets		5,480
Less valuation allowance		(862)
Net deferred tax assets		4,618
Deferred tax liabilities
Deferred revenue		(57)
Property, plant and equipment		(962)
Intangible assets		(357)
Other		(120)
Gross deferred tax liabilities		(1,496)
Net deferred tax assets		$ 3,122