Fair Value Measurements Fair Value, Assets Measured on Nonrecurring Basis Using Unobservable Inputs (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	$ (38)	$ (59)
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fair Value	67	44
Nonrecurring fair value losses	(33)	(52)
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Market Approach Valuation Technique [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Operating Lease Equipment	28	25
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Income Approach Valuation Technique [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value	39	19
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Operating Lease Equipment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	(21)	(31)
Fair Value Measurements Nonrecurring [Member] | Level 3 [Member] | Property, Plant and Equipment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonrecurring fair value losses	$ (12)	$ (21)