Financial and Other Derivative Instruments (Netting Offsets Reconciliation to Balance Sheet) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Derivative Asset, Current	$ 99	$ 108
Derivative Assets, Noncurrent	27	39
Derivative Liabilities, Current	(195)	(125)
Derivative Liabilities, Noncurrent	(43)	(26)
Derivative Asset [Member]
Derivative [Line Items]
Derivative Asset, Current	691	862
Derivative Assets, Noncurrent	142	154
Derivative Liabilities [Member]
Derivative [Line Items]
Derivative Liabilities, Current	(773)	(879)
Derivative Liabilities, Noncurrent	(163)	(141)
Counterparty Netting [Member]
Derivative [Line Items]
Derivative Asset, Current	(566)	(754)
Derivative Assets, Noncurrent	(115)	(115)
Derivative Liabilities, Current	566	754
Derivative Liabilities, Noncurrent	115	115
Collateral Adjustment [Member]
Derivative [Line Items]
Derivative Asset, Current	(26)	0
Derivative Assets, Noncurrent	0	0
Derivative Liabilities, Current	12	0
Derivative Liabilities, Noncurrent	$ 5	$ 0

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References+ Details