Annual report pursuant to Section 13 and 15(d)

Income Taxes - Components of Deferred Tax Assets and Liabilities (Details)

v3.8.0.1
Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 22, 2017
Dec. 21, 2017
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Operating Loss Carryforwards [Line Items]            
Valuation Allowance, Deferred Tax Asset, Decrease       $ 446,000,000    
Deferred tax assets            
Federal and foreign NOL carryforwards and credits $ 960,000,000     960,000,000 $ 1,060,000,000  
State NOL carryforwards and credits 188,000,000     188,000,000 183,000,000  
Deferred gain 46,000,000     46,000,000 77,000,000  
Share-based compensation expense 16,000,000     16,000,000 53,000,000  
Derivative instruments 15,000,000     15,000,000 47,000,000  
Long-term debt 16,000,000     16,000,000 18,000,000  
Other 30,000,000     30,000,000 13,000,000  
Less: valuation allowance (806,000,000)     (806,000,000) (1,252,000,000)  
Total deferred tax assets 465,000,000     465,000,000 199,000,000  
Deferred tax liabilities            
Investment in limited partnership (391,000,000)     (391,000,000) (76,000,000)  
Convertible debt (65,000,000)     (65,000,000) (118,000,000)  
Property, plant and equipment (6,000,000)     (6,000,000) (5,000,000)  
Total deferred tax liabilities (462,000,000)     (462,000,000) (199,000,000)  
Net deferred tax assets $ 3,000,000     $ 3,000,000 $ 0  
Decrease in effective tax rate due to adoption of ASU 2016-09       6.20% (0.00%) (0.00%)
U.S. corporate income tax rate 21.00% 21.00% 35.00% 35.00% 35.00% 35.00%
Reduction to U.S. net deferred tax assets due to U.S. tax reform rate change       $ 404,000,000    
Increase in effective tax rate due to U.S. tax reform rate change       71.40% 0.00% 0.00%
Income tax expense, impact due to U.S. tax reform rate change       $ 0    
Federal Tax [Member]            
Operating Loss Carryforwards [Line Items]            
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration $ 4,700,000,000     4,700,000,000    
Deferred Tax Assets, Tax Credit Carryforwards 18,000,000     18,000,000    
State Tax [Member]            
Operating Loss Carryforwards [Line Items]            
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration 2,300,000,000     2,300,000,000    
Deferred Tax Assets, Tax Credit Carryforwards $ 4,000,000     4,000,000    
U.K Tax [Member]            
Operating Loss Carryforwards [Line Items]            
Valuation Allowance, Deferred Tax Asset, Decrease       $ 9,000,000