Equipment, Office Facilities, and Property (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equipment, Office Facilities, and Property [Abstract]
Depreciation and amortization expense for equipment, office facilities, and property	$ 179	$ 155	$ 154