Fair Value of Financial Instruments, Balance Sheet Classification (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Assets	$ 14	$ 10
Liabilities	72	109
Derivatives Designated as Hedges Instruments
Derivatives, Fair Value [Line Items]
Assets	14	9
Liabilities	66	95
Derivatives Designated as Hedges Instruments | Current Assets
Derivatives, Fair Value [Line Items]
Assets	10	8
Derivatives Designated as Hedges Instruments | Non-Current Assets
Derivatives, Fair Value [Line Items]
Assets	4	1
Derivatives Designated as Hedges Instruments | Current Liabilities
Derivatives, Fair Value [Line Items]
Liabilities	62	83
Derivatives Designated as Hedges Instruments | Non-Current Liabilities
Derivatives, Fair Value [Line Items]
Liabilities	4	12
Derivatives not Designated as Hedges Instruments
Derivatives, Fair Value [Line Items]
Assets	0	1
Liabilities	6	14
Derivatives not Designated as Hedges Instruments | Current Assets
Derivatives, Fair Value [Line Items]
Assets	0	1
Derivatives not Designated as Hedges Instruments | Non-Current Assets
Derivatives, Fair Value [Line Items]
Assets	0	0
Derivatives not Designated as Hedges Instruments | Current Liabilities
Derivatives, Fair Value [Line Items]
Liabilities	6	14
Derivatives not Designated as Hedges Instruments | Non-Current Liabilities
Derivatives, Fair Value [Line Items]
Liabilities	$ 0	$ 0