Fair Value of Derivative Financial Instruments, Balance Sheet Classification (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Assets	$ 10	$ 37
Liabilities	109	18
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
After-tax loss on cash flow hedges included in accumulated other elements of comprehensive income and in noncontrolling interests	47
Recognized as a reduction in earnings in 2015	38
Derivatives not Designated as Hedges [Member]
Derivatives, Fair Value [Line Items]
Assets	1	6
Liabilities	14	6
Derivatives not Designated as Hedges [Member] | Foreign Exchange Contracts [Member] | Current Assets [Member]
Derivatives, Fair Value [Line Items]
Assets	1	6
Derivatives not Designated as Hedges [Member] | Foreign Exchange Contracts [Member] | Non-Current Assets [Member]
Derivatives, Fair Value [Line Items]
Assets	0	0
Derivatives not Designated as Hedges [Member] | Foreign Exchange Contracts [Member] | Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liabilities	14	6
Derivatives not Designated as Hedges [Member] | Foreign Exchange Contracts [Member] | Non-Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liabilities	0	0
Derivatives Designated as Hedges [Member] | Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Assets	9	31
Liabilities	95	12
Derivatives Designated as Hedges [Member] | Foreign Exchange Contracts [Member] | Current Assets [Member]
Derivatives, Fair Value [Line Items]
Assets	8	28
Derivatives Designated as Hedges [Member] | Foreign Exchange Contracts [Member] | Non-Current Assets [Member]
Derivatives, Fair Value [Line Items]
Assets	1	3
Derivatives Designated as Hedges [Member] | Foreign Exchange Contracts [Member] | Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liabilities	83	10
Derivatives Designated as Hedges [Member] | Foreign Exchange Contracts [Member] | Non-Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liabilities	$ 12	$ 2