Financial Instruments (Fair Value Hierarchy Classification) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Fair Value, Measurements, Recurring [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member]	Sep. 30, 2013 Fair Value, Measurements, Recurring [Member] Quoted price in active markets (Level 1) [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Quoted price in active markets (Level 1) [Member]	Sep. 30, 2013 Fair Value, Measurements, Recurring [Member] Significant other observable inputs (Level 2) [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Significant other observable inputs (Level 2) [Member]	Sep. 30, 2013 Fair Value, Measurements, Recurring [Member] Unobservable inputs (Level 3) [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Unobservable inputs (Level 3) [Member]	Sep. 30, 2013 Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2013 Fair Value, Measurements, Nonrecurring [Member] Quoted price in active markets (Level 1) [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Quoted price in active markets (Level 1) [Member]	Sep. 30, 2013 Fair Value, Measurements, Nonrecurring [Member] Significant other observable inputs (Level 2) [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Significant other observable inputs (Level 2) [Member]	Sep. 30, 2013 Fair Value, Measurements, Nonrecurring [Member] Unobservable inputs (Level 3) [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Unobservable inputs (Level 3) [Member]	Sep. 30, 2013 Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure [Member]	Sep. 30, 2013 Estimate of Fair Value, Fair Value Disclosure [Member] Quoted price in active markets (Level 1) [Member]	Sep. 30, 2013 Estimate of Fair Value, Fair Value Disclosure [Member] Significant other observable inputs (Level 2) [Member]	Sep. 30, 2013 Estimate of Fair Value, Fair Value Disclosure [Member] Unobservable inputs (Level 3) [Member]	Sep. 30, 2013 Portion at Other than Fair Value Measurement [Member]	Dec. 31, 2012 Portion at Other than Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure			$ 882	$ 781	$ 882	$ 781	$ 0	$ 0	$ 0	$ 0
Derivative Assets			86	128	0	0	86	128	0	0
Derivative Financial Instruments, Liabilities, Fair Value Disclosure			(88)	(149)	0	0	(88)	(149)	0	0
Equity Method Investments, Fair Value Disclosure												432		0		432		0
Business Dispositions, Fair Value Disclosure											40	84	0	0	40	84	0	0
Net Gains on Non-recurring Fair Value Measurement	38	220
Net Gains of Sale of Controlling Interest		357
Non Cash Net Gain		272
Long-term receivables Fair Value Disclosure																			642	464	0	642	0	651	499
Customer Financing Notes Receivable Fair Value Disclosure																			388	371	0	388	0	438	375
Short Term borrowings																			(303)	(503)	0	(100)	(203)	(303)	(503)
Long-term debt (excluding capitalized leases) Fair Value Disclosure																			(20,937)	(25,606)	0	(20,830)	(107)	(20,837)	(22,665)
Other long-term liabilities, Fair Value Disclosure																			(257)	(167)	0	(257)	0	(284)	(182)
Equity Method Investment Other Than Temporary Impairment	(25)	103
Gain (Loss) on Disposition of Business	193
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal		32
Net Gains on Previously Held Interests		$ 34