Off-Balance Sheet Risk and Guarantees, Concentrations of Credit Risk and Fair Value of Financial Instruments - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Contingently liable for bank guarantees and standby letters of credit issued on the company's behalf	$ 1,100
Liability to financial institutions for financial letters of credit and other guarantees issued on the Company's behalf	36
Liability for insurance bonds issued on the company's behalf	36
Fair value of long term debt	2,900	$ 2,900
Face value of long term debt, excluding original issuance cost	$ 2,700	$ 2,700