Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives	$ 28	$ 86
Derivatives	89	149
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	263	266
Derivatives	28	86
Total Assets at Fair Value	291	352
Derivatives	89	149
Total Liabilities at Fair Value	89	149
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	263	266
Derivatives	0	21
Total Assets at Fair Value	263	287
Derivatives	80	148
Total Liabilities at Fair Value	80	148
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Derivatives	28	65
Total Assets at Fair Value	28	65
Derivatives	9	1
Total Liabilities at Fair Value	9	1
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	0	0
Derivatives	0	0
Total Assets at Fair Value	0	0
Derivatives	0	0
Total Liabilities at Fair Value	$ 0	$ 0