Fair Value (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases	$ 6	$ 6
Notes receivable, excluding capital leases		6
Notes receivable - affiliates	192	26
Notes receivable - affiliates		26
Short-term borrowings - affiliates	81	64
Short term borrowing - affiliates		64
Long-term Debt	5,453	5,051
Long-term debt		5,740
Fair Value, Inputs, Level 1 [Member]
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases	0
Notes receivable - affiliates	0
Short term borrowing - affiliates	0
Long-term debt	0
Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases	0
Notes receivable - affiliates	0
Short term borrowing - affiliates	0
Long-term debt	6,128
Fair Value, Inputs, Level 3 [Member]
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases	6
Notes receivable - affiliates	192
Short term borrowing - affiliates	81
Long-term debt	$ 43