v3.6.0.2
Derivative Instruments (Details 2) (Details) - USD ($)
$ in Millions
Dec. 31, 2016
Dec. 31, 2015
Derivatives, Fair Value [Line Items]    
Derivative Assets, Current $ 1,725 $ 1,698
Long-term derivative assets 543 313
Total derivative assets 2,268 2,011
Derivative Liabilities, current 1,630 1,734
Long-term derivative liabilities 476 473
Derivative Liability, Fair Value, Gross Liability 2,106 2,207
Net derivative assets (liabilities) 162 (196)
Designated as Hedging Instrument [Member]    
Derivatives, Fair Value [Line Items]    
Total derivative assets 29 1
Derivative Liability, Fair Value, Gross Liability 58 90
Not Designated as Hedging Instrument [Member]    
Derivatives, Fair Value [Line Items]    
Total derivative assets 2,239 2,010
Derivative Liability, Fair Value, Gross Liability 2,048 2,117
Energy Related Derivative [Member]    
Derivatives, Fair Value [Line Items]    
Derivative assets, current 1,724 1,698
Derivative Asset, Noncurrent 515 312
Total derivative assets 2,239 2,010
Derivative Liability, Current 1,602 1,697
Derivative Liability, Noncurrent 446 420
Derivative Liability, Fair Value, Gross Liability 2,048 2,117
Net derivative assets (liabilities) 191 (107)
Energy Related Derivative [Member] | Not Designated as Hedging Instrument [Member]    
Derivatives, Fair Value [Line Items]    
Total derivative assets 2,239 2,010
Derivative Liability, Fair Value, Gross Liability 2,048 2,117
Interest Rate Contract [Member]    
Derivatives, Fair Value [Line Items]    
Derivative assets, current 1 0
Derivative Asset, Noncurrent 28 1
Total derivative assets 29 1
Derivative Liability, Current 28 37
Derivative Liability, Noncurrent 30 53
Derivative Liability, Fair Value, Gross Liability 58 90
Net derivative assets (liabilities) (29) (89)
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]    
Derivatives, Fair Value [Line Items]    
Total derivative assets 29 1
Derivative Liability, Fair Value, Gross Liability $ 58 $ 90