Commitments and Contingent Liabilities - Additional information (Details) - USD ($) $ in Millions		1 Months Ended		3 Months Ended	12 Months Ended
	Oct. 17, 2013	Nov. 30, 2013	Oct. 31, 2013	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Line of Credit Facility [Line Items]
Litigation judgment claims	$ 2,500
Surety bond, annual fee					$ 5	$ 7
Surety bond fees recovered during the period				$ 13
Maximum lease period					25 years
Net rental expense under operating leases					$ 8	10	$ 11
HSBC North America [Member]
Line of Credit Facility [Line Items]
Annual fee to guarantor					$ 4	$ 6
Securities Litigation [Member]
Line of Credit Facility [Line Items]
Litigation judgment claims		$ 2,500	$ 2,500