Income Taxes - Deferred income taxes (assets and liabilities netted by jurisdiction) as classified in the Consolidated Statements of Financial Position (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred income taxes
Deferred tax assets - current	$ 232	$ 212
Deferred tax assets — non-current	141	144
Deferred tax liabilities - current	(1)	(2)
Deferred tax liabilities — non-current	(176)	(313)
Net deferred tax asset	$ 196	$ 41