Fair Value (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases	$ 6	$ 5
Short-term borrowings - affiliates	59	80
Other Short-term Borrowings	96	130
Long-term debt	5,185	4,963
Fair Value, Inputs, Level 1 [Member]
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases	0	0
Short-term borrowings affiliates	0	0
Short-term Debt, Fair Value	0	0
Long-term debt	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases	0	0
Short-term borrowings affiliates	59	0
Short-term Debt, Fair Value	96	130
Long-term debt	4,636	5,021
Fair Value, Inputs, Level 3 [Member]
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases	6	5
Short-term borrowings affiliates	0	80
Short-term Debt, Fair Value	0	0
Long-term debt	$ 688	$ 620