Financial Instruments (Fair Value Hierarchy Classification) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Fair Value, Measurements, Recurring [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member]	Jun. 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]	Jun. 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]	Jun. 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]	Jun. 30, 2013 Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member]	Jun. 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]	Jun. 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]	Jun. 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]	Jun. 30, 2013 Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure [Member]	Jun. 30, 2013 Estimate of Fair Value, Fair Value Disclosure [Member] Quoted price in active markets (Level 1) [Member]	Jun. 30, 2013 Estimate of Fair Value, Fair Value Disclosure [Member] Significant other observable inputs (Level 2) [Member]	Jun. 30, 2013 Estimate of Fair Value, Fair Value Disclosure [Member] Unobservable inputs (Level 3) [Member]	Jun. 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			$ 827	$ 781	$ 827	$ 781	$ 0	$ 0	$ 0	$ 0
Derivative Assets			98	128	0	0	98	128	0	0
Derivative Financial Instruments, Liabilities, Fair Value Disclosure			(205)	(149)	0	0	(205)	(149)	0	0
Equity Method Investments, Fair Value Disclosure												432		0		432		0
Business Dispositions, Fair Value Disclosure											13	84	0	0	13	84	0	0
Net Gains on Non-recurring Fair Value Measurement	38	222
Net Gains of Sale of Controlling Interest		357
Non Cash Net Gain		272
Long-term receivables Fair Value Disclosure																			586	464	0	586	0	646	499
Customer Financing Notes Receivable Fair Value Disclosure																			354	371	0	354	0	408	375
Short Term borrowings																			(196)	(503)	0	(50)	(146)	(196)	(503)
Long-term debt (excluding capitalized leases) Fair Value Disclosure																			(21,890)	(25,606)	0	(21,787)	(103)	(21,412)	(22,665)
Other long-term liabilities, Fair Value Disclosure																			(250)	(167)	0	(250)	0	(279)	(182)
Equity Method Investment Other Than Temporary Impairment		103
Gain (Loss) on Disposition of Business	193
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal		$ 32