Fair Value (Fair Value of Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases Carrying Amount	$ 13	$ 10
Notes receivable - affiliates Current	0	200
Long-term debt Carrying Amount	5,032	5,146
Fair Value, Inputs, Level 1 [Member]
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases Fair Value	0	0
Notes receivable - affiliates, fair value	0	0
Long-term debt Fair Value	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases Fair Value	0	0
Notes receivable - affiliates, fair value	0	0
Long-term debt Fair Value	5,125	5,253
Fair Value, Inputs, Level 3 [Member]
Fair Value of Financial Instruments [Line Items]
Notes receivable, excluding capital leases Fair Value	13	10
Notes receivable - affiliates, fair value	0	200
Long-term debt Fair Value	304	136
Affiliates [Member]
Fair Value of Financial Instruments [Line Items]
Short-term borrowings - affiliates Carrying Amount	63	58
Affiliates [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value of Financial Instruments [Line Items]
Short-term Debt, Fair Value	0	0
Affiliates [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value of Financial Instruments [Line Items]
Short-term Debt, Fair Value	0	0
Affiliates [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value of Financial Instruments [Line Items]
Short-term Debt, Fair Value	$ 63	$ 58