Fair Value of Financial Instruments, Balance Sheet Classification (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Assets	$ 23	$ 37
Liabilities	18	18
Derivatives Designated as Hedges Instruments [Member]
Derivatives, Fair Value [Line Items]
Assets	21	31
Liabilities	15	12
Derivatives Designated as Hedges Instruments [Member] | Current Assets [Member]
Derivatives, Fair Value [Line Items]
Assets	18	28
Derivatives Designated as Hedges Instruments [Member] | Non-Current Assets [Member]
Derivatives, Fair Value [Line Items]
Assets	3	3
Derivatives Designated as Hedges Instruments [Member] | Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liabilities	13	10
Derivatives Designated as Hedges Instruments [Member] | Non-Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liabilities	2	2
Derivatives not Designated as Hedges Instruments [Member]
Derivatives, Fair Value [Line Items]
Assets	2	6
Liabilities	3	6
Derivatives not Designated as Hedges Instruments [Member] | Current Assets [Member]
Derivatives, Fair Value [Line Items]
Assets	2	6
Derivatives not Designated as Hedges Instruments [Member] | Non-Current Assets [Member]
Derivatives, Fair Value [Line Items]
Assets	0	0
Derivatives not Designated as Hedges Instruments [Member] | Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liabilities	3	6
Derivatives not Designated as Hedges Instruments [Member] | Non-Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liabilities	$ 0	$ 0