Fair Value Measurements (Details 2) In Millions, unless otherwise specified	Dec. 31, 2014 Eurobond repaid July 2014 EUR (€)	Dec. 31, 2014 Carrying Amount USD ($)	Dec. 31, 2013 Carrying Amount USD ($)	Dec. 31, 2014 Carrying Amount Eurobond repaid July 2014 USD ($)	Dec. 31, 2013 Carrying Amount Eurobond repaid July 2014 USD ($)	Dec. 31, 2014 Fair Value USD ($)	Dec. 31, 2013 Fair Value USD ($)	Dec. 31, 2014 Fair Value Eurobond repaid July 2014 USD ($)	Dec. 31, 2013 Fair Value Eurobond repaid July 2014 USD ($)
Financial Instruments
Eurobond securities repaid July 2014				$ 0	$ 1,424			$ 0	$ 1,447
Long-term debt, excluding current portion		6,731	4,326			7,203	4,463
Principal amount	€ 1,025