v3.3.1.900
Variable Interest Entities and Unconsolidated Investments (Equity Method Investment Summarized Financial Information) (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Equity Method Investment, Summarized Financial Information, Assets [Abstract]                        
Cash and cash equivalents $ 906       $ 717       $ 906 $ 717 $ 941 $ 1,284
Assets, Current 4,095       4,220       4,095 4,220    
Property, plant and equipment, net 13,012       13,190       13,012 13,190    
Other assets 1,192       385       1,192 385    
Total assets 18,833       18,378       18,833 18,378    
Equity Method Investment, Summarized Financial Information, Liabilities [Abstract]                        
Debt, current portion 221       199       221 199    
Liabilities, Current 3,048       3,199       3,048 3,199    
Debt, net of current portion 11,868       11,083       11,868 11,083    
Long-term derivative liabilities 473       444       473 444    
Total liabilities 15,666       14,947       15,666 14,947    
Equity Method Investment Summarized Financial Information, Equity [Abstract]                        
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest 3,167       3,431       3,167 3,431 3,568 $ 4,056
Total liabilities and stockholders’ equity 18,833       18,378       18,833 18,378    
Equity Method Investment, Summarized Financial Information, Gross Profit (Loss) [Abstract]                        
Operating revenues 1,436 $ 1,948 $ 1,442 $ 1,646 1,939 $ 2,187 $ 1,939 $ 1,965 6,472 8,030 6,301  
Costs and Expenses                 5,641 6,696 5,441  
Income from operations 22 $ 466 $ 201 $ 166 390 $ 1,126 $ 329 $ 144 855 1,989 874  
Interest Revenue (Expense), Net                 624 639 690  
Other (income) expense, net                 18 21 20  
Net income                 249 961 18  
Greenfield and Whitby [Member]                        
Equity Method Investment, Summarized Financial Information, Assets [Abstract]                        
Cash and cash equivalents 50       58       50 58    
Assets, Current 14       28       14 28    
Property, plant and equipment, net 431       532       431 532    
Other assets 1       2       1 2    
Total assets 496       620       496 620    
Equity Method Investment, Summarized Financial Information, Liabilities [Abstract]                        
Debt, current portion 18       21       18 21    
Liabilities, Current 21       28       21 28    
Debt, net of current portion 251       321       251 321    
Long-term derivative liabilities 43       51       43 51    
Total liabilities 333       421       333 421    
Equity Method Investment Summarized Financial Information, Equity [Abstract]                        
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest 163       199       163 199    
Total liabilities and stockholders’ equity $ 496       $ 620       496 620    
Equity Method Investment, Summarized Financial Information, Gross Profit (Loss) [Abstract]                        
Operating revenues                 191 239 207  
Costs and Expenses                 127 168 128  
Income from operations                 64 71 79  
Interest Revenue (Expense), Net                 18 23 24  
Other (income) expense, net                 0 0 (3)  
Net income                 $ 46 $ 48 $ 58