Derivative Instrument and Hedging Activities (Details) (Interest Rate Contract [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 0	$ 0
Derivative Liability, Fair Value, Gross Liability	32	25
Price risk management liabilities [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	10	10
Non-current price risk management liabilities [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	$ 22	$ 15