Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Fair Value of Derivative Contracts (Details)

v3.5.0.2
Summary of Significant Accounting Policies - Fair Value of Derivative Contracts (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Jun. 30, 2016
Derivative Financial Instruments      
Fair value of commodity derivative contracts     $ 2,100
Basis of Presentation      
Other comprehensive income (loss) $ 0 $ 0  
Morgan Stanley      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     568
Barclays      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     461
JP Morgan      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     388
Citigroup      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     126
Wells Fargo      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     204
Scotiabank      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     148
BNP Paribas      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     81
Toronto Dominion Bank      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     51
Canadian Imperial Bank of Commerce      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     30
Fifth Third Bank      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     24
Bank of Montreal      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     13
SunTrust      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     6
Capital One      
Derivative Financial Instruments      
Fair value of commodity derivative contracts     $ 4