Derivatives and Risk Management Activities (Details 6) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivative Asset Positions
Gross Position - Asset	$ 244	$ 493
Netting Adjustment	(39)	(262)
Cash collateral received	(121)	(133)
Net Position - Asset	84	98
Derivative Liability Positions
Gross Position - Liability	(127)	(384)
Netting Adjustment	39	262
Net Position - Liability	(88)	(122)
Other current assets
Derivative Asset Positions
Net Position - Asset	72	71
Other long-term assets, net
Derivative Asset Positions
Net Position - Asset	12	27
Other current liabilities
Derivative Liability Positions
Net Position - Liability	(47)	(91)
Other long-term liabilities and deferred credits
Derivative Liability Positions
Net Position - Liability	$ (41)	$ (31)