Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Level 3
Liabilities
Guarantees	$ 1	$ 2	$ 2
Fair Value, Measurements, Recurring
Assets
Derivative financial instruments, net	128	223	232
Total Assets	128	223	232
Liabilities
Guarantees	1	2	2
Total liabilities	1	2	2
Fair Value, Measurements, Recurring | Level 1
Assets
Derivative financial instruments, net	0	0	0
Total Assets	0	0	0
Liabilities
Guarantees	0	0	0
Total liabilities	0	0	0
Fair Value, Measurements, Recurring | Level 2
Assets
Derivative financial instruments, net	128	223	232
Total Assets	128	223	232
Liabilities
Guarantees	0	0	0
Total liabilities	0	0	0
Fair Value, Measurements, Recurring | Level 3
Assets
Derivative financial instruments, net	0	0	0
Total Assets	0	0	0
Liabilities
Guarantees	1	2	2
Total liabilities	$ 1	$ 2	$ 2