Fair Value Measurements Fair Value, Assets Measured on Nonrecurring Basis Using Unobservable Inputs (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	$ (229)	$ (96)	$ (84)
Fair Value Measurements Nonrecurring [Member] | Operating Lease Equipment [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	(170)	(81)
Fair Value Measurements Nonrecurring [Member] | Property, Plant and Equipment [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	(15)	(15)
Fair Value Measurements Nonrecurring [Member] | Other assets and Acquired intangible assets [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	(17)
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Total Fair Value	206	256
Nonrecurring fair value losses	(202)	(96)
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Market Approach Valuation Technique [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Operating Lease Equipment, Fair Value	187	216
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Income Approach Valuation Technique [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value	19	40
Other assets and Acquired intangible assets, Fair Value